An update on the nutrition of dairy sheep grazing Mediterranean pastures

Small Ruminant Research 77 (2008) 93112

Available online at www.sciencedirect.com

An update on the nutrition of daiMediterranean pastu

G. Molle a,, M. Decandia a, A.nna

duzionite of Plssari, 02008

Abstract

In the light of recent findings in sheep nutrition and feeding behaviour, the diets of grazing dairy sheep should be based on foragesencompassing a variety of complementary nutritional values and containing moderate levels of diverse plant secondary metabo-lites, until recently regarded as anti-nutritional. In lactating sheep, pastures of tannin-containing legumes like sulla (Hedysarumcoronarium)conditions. Dof grazing s(complemenof lactatingmid-lactatiotool to balanon dairy sheestimation oand establis 2008 Else

Keywords: G

1. Introdu

Dairy shMediterranleading couduction (Taeast and sou

This papeFarming: grazby P. Morand

CorresponE-mail ad

0921-4488/$doi:10.1016/jand chicory (Cichorium intybus) can be integrated with annual grasses for establishing artificial pastures under rainfediets based on these forages, while ensuring high milking performance, can mitigate the unbalance of CP to energy ratio

heep. By grazing sulla and Italian ryegrass (50:50 by area) as spatially adjacent monocultures or in timely sequencetary grazing) sheep eat more and perform better than by grazing the ryegrass pasture only. Concentrate supplementationsheep should be preferably based on sources rich in digestible plant fiber (soyhulls or beet pulps), particularly fromn onwards and when supplementation levels are high. Milk urea concentration is confirmed as a useful monitoringce protein nutrition and curb the waste of N at animal and system level. Finally, challenging tasks for future researchep grazing management and nutrition are on-farm application of recent technological advances, such as image-basedf pasture biomass and quality, evaluation of sheep dietary quality by faecal Near Infrared Reflectance Spectrometry,

hment of remote control systems.vier B.V. All rights reserved.

razing; Dairy sheep; Milk; Nutrition; Behaviour; Mediterranean pastures

ction

eep production is mainly located in the EUean countries, with Italy and Greece beingntries for sheep stock, milk and cheese pro-ble 1). Other Mediterranean countries of thethern shores and Eastern European countries,

r is part of the special issue entitled Sheep and Goating systems of production and development guest edited-Fehr.ding author. Tel.: +39 079 387233; fax: +39 079 389450.dress: [email protected] (G. Molle).

such as Romania (Table 1), also play a role in the sheepmilk production sector. In most of these regions, dairysheep feeding is based on pasture grazing, although pro-duction systems range from highly extensive (based onnatural grassland or rangeland) to very intensive, basedon forage crops, agriculture by-products and concen-trates, as in the case of complete-diet based productionsystems (Landau and Molle, 2004).

This review focuses primarily on dairy sheep nutri-tion in Mediterranean grazing systems. Basic principleswill be updated and feeding and management strategieswill be derived keeping the following as basic target:production of quality foods modulated by agronomic,

see front matter 2008 Elsevier B.V. All rights reserved..smallrumres.2008.03.003S.Y. Landau b, A. Caa AGRIS Sardegna, Dipartimento per la Ricerca nelle Pro

b A.R.O., Department of Natural Resources and Agronomy, Instituc Dipartimento di Scienze Zootecniche, University of Sa

Available online 7 Mayry sheep grazingres

Cabiddu a,s cAnimali, 07040 Olmedo, Italyant Sciences, Bet Dagan 50250, Israel7100 Sassari, Sardinia, Italy

94 G. Molle et al. / Small Ruminant Research 77 (2008) 93112

Table 1Dairy sheep census and production in Europe (FAO, 2005)

Heads Milk production Cheese production

NPortugalSpain 2France 1Italy 7Albania 1Greece 7Bulgaria 1CyprusRomania 5HungaryEurope 27

N = number o

economic,ronmentalallow the fdairy sheepof Mediteral., 2007).detailed insheep milkPulina et a

Great eclarify thetems, withtheir two ming of fora(semi-extemal. In thiis updatedfocused esbased on mnutrition. Aenvironmealso briefly

Pasturesand not assheep areimportantanimals, wserved. Thwildlife proconservatiotive 92/43 Egrazing theto achieve tWallis Detoral system

managed with high stocking rates may result in environ-mental hazards such as soil erosion, nutrients runoffand leaching as well as emission of green-house gases.

e environmental aspects are to be taken into accountptimap as w

elabylthougf it w

, whicctivityaged,whichmulti-of thisbodyinto cng anfeedintationptima).airy scial ancognirelativare u

ort motersp, basea majos as want e

t of viotatedof theized ad com1000 (%) T 1000 (%) T (%)530 2.0 98 3.4 16,400 4.5

,050 7.6 400 13.9 47,500 13.0,345 5.0 264 9.2 50,000 13.6,000 25.8 820 28.6 94,350 25.7,470 2.4 76 2.6 1,200 0.3,000 25.8 700 24.4 130,000 35.5,351 5.0 116 4.0 13,000 3.5175 0.6 22 0.8 3,500 1.0,446 20.1 344 12.0 9,900 2.7750 2.8 32 1.1 780 0.2

,117 100.0 2,872 100.0 366,630 100.0

f heads; T = metric tons.

ethical (e.g. animal well-being) and envi-considerations. The ultimate objective is toarmers to make a living from locally adaptedproduction systems, which represent the core

ranean dairy sheep industry (Morand-Fehr etThe reader should refer to other sources forformation on the effect of grazed forages on

and cheese quality (Cabiddu et al., 2005;l., 2006).fforts have been made in the last decade tofunctioning of Mediterranean grazing sys-particular focus on the interactions betweenain components, i.e. the pasture consist-

ge crops or improved semi-natural pasturesnsive farming systems) and the grazing ani-s review the body of knowledge in this areaon the basis of: (i) recent applied researchpecially on dairy sheep; and (ii) evidenceore fundamental research on sheep and cattlespects such as agronomic performance and

ntal impact of grazing management will be

Thesfor osheeand D

Apart oence

seleenvismal,in anentthe ence

grazithatadapfor o2001

Dartifibe retheirmeatsupp(winturesplaylambpregnpoinand rtionfertilswardiscussed.are nowadays regarded as multi-use areas,

a simple feeding resource. Areas where dairyextensively managed are often consideredhabitats for many wild species, plants andhose biodiversity should be adequately pre-is is particularly the case for natural parks,tected areas or any areas subjected to naturen schemes (e.g. Natura 2000 Network, Direc-EC). When adequate management is applied,se areas represents a valuable economic wayhe conservation targets (Scimone et al., 2007;Vries et al., 2007). On the other hand, pas-s using forage crops intensively cropped and

plots and ndairy sheep

The folnutritive vcrops (Secestablishedtures or m(Section 4)plementatimethods fonants, with(Section 6)resuming tand envisal management of grazing resources for dairyell as for other herbivore species (e.g. Peyraud, 2006).h this review is mainly devoted to nutrition,ill address behavioural aspects such as prefer-h is the unconstrained expression of feeding. An animal-friendly approach is in factentailing a dialogue between man and ani-keeps in mind the grazing system as a whole

disciplinary perspective. The animal compo-dialogue is based on animal behaviour, i.e.

language. The importance of taking prefer-onsideration while managing the nutrition ofimals stands on the widely accepted conceptg selectivity originates in long-term animalto its environment, which is a pre-requisite

l life-long performance (Prache and Peyraud,

heep grazing systems are usually based ond natural or semi-natural pastures. It must

zed that both play an important role althoughe weights on annual production of milk andsually quite different: forage crops usuallyst of the productive stock during lactation

ring), while the natural and semi-natural pas-d on annual self-regenerating forage species,r role for the grazing nutrition of replacementell as for the maintenance of non-lactating,

wes (summerautumn). From an agronomicew, forage crops are established, cultivatedfrom year-to-year across the arable propor-farm, whereas the natural pasture is only

nd re-established on occasions, usually whenposition deteriorates. This mosaic of croppedatural grassland is typical of Mediterraneanfarm landscape.

lowing sections will primarily address: thealue of Mediterranean pastures and foragetion 2); the choice of forage species to be(Section 3); their spatial distribution (as mix-

onocultures); and their grazing management. Then the focus will be directed on the sup-on of grazing sheep (Section 5). Afterwards,r monitoring the nutrition of grazing rumi-particular focus on sheep, will be envisaged. A final section (Section 7) is aimed at bothhe main concepts from a practical standpoint,ging future research needs.

G. Molle et al. / Small Ruminant Research 77 (2008) 93112 95

Table 2Dry matter percentage, chemical composition (%DM) and nutritive value of some Mediterranean forages as selected by lactating sheep (hand-pluckedsamples)Forage N DM CP NDF NSC Tannic phenols NEL (Mcal/kg DM) CP/NEL (g/Mcal)Annual ryegrassa 72 19.4 (3.2) 20.1 (1.8) 39.3 (5.0) 22.7 (8.8) 0.3 (Sullaa 24 16.4 (1.8) 23.2 (4.0) 29.8 (3.7) 33.4 (10.2) 2.1 (Burr medica 24 19.1 (2.8) 28.1 (1.2) 29.6 (3.9) 30.1 (5.1) 0.2 (Subclovera 24 19.6 (1.9) 21.6 (2.0) 31.7 (5.3) 31.5 (6.3) 1.0 (Sullab 3 15.7 (2.4) 23.4 (2.7) 37.7 (2.5) 25.4 (5.7) 2.6 (Burr medicb 3 18.1 (3.9) 24.1 (2.8) 35.9 (6.1) 27.3 (3.5) 0.6 (Chicoryb 3 12.0 (2.9) 14.5 (0.9) 35.0 (0.7) 33.7 (1.6) 1.0 (Safflowerb 3 15.0 (1.5) 18.6 (7.6) 37.9 (8.3) 30.2 (4.2) 2.4 (Means and (S.D.) N = number of samples; DM = dry matter; CP = crude protein; NDF = ncarbohydrates; NEL = net energy for lactation.

a Forages at growing phase (JanuaryApril) (unpublished data).b Forages at early reproductive phase (May) (Landau et al., 2005b).

2. Nutritive value and nutritional unbalances ofMediterranean pasture and forage crops

Mediterannual foranutritive vaSheep usuaTherefore,than that o

As showgrass and lehigh nutritithey also hwhich, in eby a highfraction A)al., 1996).tions occasherbage CPcally exper

Fig. 1. CrudeMediterraneaburr medic; Rare: A: NPN;neutral detergC: acid deterg

to energy raproductionmilk yield

instaluble Non in tea inentratihe perinia thten higg, whue th

he exased eost of); (ii) ienviroency fN (Caased cble heonia eranean grazed forages consist primarily ofges, which undergo abrupt changes in theirlue during the course of the growing cycle.lly graze from the top leafy layer downwards.the quality of the ingested forage is higher

n offer.n in Table 2, the selected components of bothgume forages (hand-plucked samples) have ave value during growth period. Unfortunately,ave very high levels of crude protein (CP),arly stages of growth, is often characterizedproportion of non-protein nitrogen (NPN orand soluble protein N (fraction B1, Licitra et

In grasses such as Italian ryegrass these frac-ionally make more than 40% of total selected

(Fig. 1). In this nutritional scenario, typi-ienced by early to mid lactation ewes, the CP

manyof soductito urconc

ing tSardis ofsprindiet d

Tincrethe c1970withefficiurea-

decrepossiammprotein fractions in selected plant components of fourn forages, grazed by sheep during growing phase. BM:Y: annual ryegrass; SC: subclover; SU: sulla. FractionsB1: buffer soluble protein; B2: buffer insoluble protein ent soluble protein; B3: neutral detergent soluble protein;ent insoluble protein (Licitra et al., 1996).

stated by BAt large

cope with tany Meditefor CP/eneseason. Nemitigate th over ener

et al., 2007

1. Decreasfertiliza0.1) 1.85 (0.1) 119 (24)0.6) 1.78 (0.2) 133 (33)0.1) 1.86 (0.1) 152 (9)0.3) 1.70 (0.1) 128 (16)0.1) 1.55 (0.1) 151 (23)0.1) 1.74 (0.1) 141 (6)0.4) 1.73 (0.0) 86 (5)1.0) 1.75 (0.0) 100 (6)eutral detergent fiber; NSC = calculated non-structural

tio is often above the required levels for milk(approximately 110120 g CP/Mcal NEL forranging between 1000 and 2000 g/day). Innces, this high ratio and the high proportioninduce very fast and excessive ammonia pro-

he rumen, which is converted in large amountthe liver. As a result, blood and milk ureaons in grazing sheep are often very high dur-iod of active pasture growth. For example, ine concentration of milk urea of bulk samplesher than 60 mg/100 ml during winterearly

ich is a clear sign of nitrogen excess in thee nutritional unbalance of pasture.cess of CP over energy brings about: (i)nergy requirements of the animals, due toammonia conversion into urea (Tyrrell et al.,ncreased N excretion, mostly as urinary urea,nmental impact; (iii) low nitrogen utilizationor milk, with dietary N being wasted as milknnas et al., 1998; Landau et al., 2005a); (iv)onception rates (Branca et al., 2000); and (v)alth problems, such as laminitis, triggered byxcesses and subsequent rumen alkalosis, as

ertoni (1995) for dairy cattle., no unique solution can be put forward tohis nutritional unbalance. No monoculture ofrranean pasture species exists that is balancedrgy for more than a short part of the grazingvertheless, the following ways can at leaste excess of CP mainly degradable proteingy (e.g. Peyraud and Delaby, 2006; Hoekstra):

ing the herbage CP content by reducing Ntion levels, increasing the length of grazing


rotation, restricting access to pasture to afternoonhours, or other means;

2. Increasing the herbage energy content through a raiseof non-structural carbohydrates (NSC) and in partic-ular wa

3. Lowerinreducefor insta

4. Using sexcess

trates) o(Section

Points 1negative coand Astiarbetween disynchronizand N com

Manageenergy rati

3. Choicesheep graz

Benefitslow proteias grass vagrazed pla(for legumphenologicing or heaconditions)nutrition (ling managcontinuousvars of perselected re2040% (Dgrowing sethat lambshad higherwhich resuthe controexclosure-cresults. Hoduction meabove studmentationreduced amgeneral, inadvisable f

preference in sheep (Dove et al., 1999) and cattle (Smit etal., 2006), but the effects of WSC genetically enrichedforages on intake and performance are not conclusiveyet. Although the technique of spray-topping low doses

yphosSC i

attracrdoushe usenninsestedever, o

ir protp perfoctually

es co(CT),narium-livedhas rew by Mg pos

e (in s003),Burket levetion ahan usion o), impidoularmanc). Amerate c

(Table of999).he respre orm rigum) ares ono highlemenonocu

p duriigherspp.heep

uce mal grasmporater soluble carbohydrates (WSC);g the degradability of herbage N in a way to

the ammonia loss at rumen level, by grazingnce forages inclusive of condensed tannins;upplements aimed at counterbalancing the

of CP (e.g. high starch-low protein concen-r additives such as NH3-binding components5).

and 2 are related to each other since there is arrelation between WSC and CP (e.g. Peyraudraga, 1998). Points 14 refer to the balanceetary nutrients (energy and protein) and theation of rumen degradation of carbohydrateponents.ment techniques used to mitigate the CP too (point 1) will be described in Section 4.

of Mediterranean forages for dairying systems

could be obtained from grazing high energy-n forages (e.g. Rearte et al., 2003), suchrieties rich in WSC. The WSC content of

nts is usually 520% (for grass) or 312%es) depending on forage species and variety,al stage (higher at the beginning of flower-ding), weather pattern (higher under sunny, time of day (higher in the afternoon), soilower with abundant N fertilization) and graz-ement (higher under rotational grazing than

stocking; Jarrige et al., 1995). New culti-ennial ryegrass (Lolium perenne) have beencently whose WSC contents overpass byM basis) that of a standard cultivar across allason (Lee et al., 2001). These authors foundgrazing a WSC-rich cultivar (cv. Ba11353)average daily gain and carrying capacity,

lted in 23% higher gain per hectare thanl. The off-take of pasture measured by theage method did not help to explain thesewever, in a parallel test of in vitro gas pro-asurement of herbage samples taken in they, the WSC-rich ryegrass had increased fer-rate and glucogenic/lipogenic ratio as well as

monia concentration (Lee et al., 2003). Increasing the WSC in grazed herbage can beor many reasons, such as the enhancement of

of glthe Wis unhaza

Tas tasuggHowimpashee

Alegumninscoro

longtus),revielowinintakal., 2(e.g.at guexcre

ces temis2002(Spirperfo2005modlevelmanc

al., 1T

cultuLoliutiorstudiate tsuppas m

sheethe hgrassthat sprodannu

or teate (Siever-Kelly et al., 1999) for enhancingn annual grass-based pastures is effective, ittive because it gives the perception of beingfor the environment.of forages which contain components such

able to limit N degradation in the rumen (aspreviously in point 3) is prone to success.ne must remember that excess dietary tanninsein metabolism, enzyme activity, and overallrmance (Silanikove et al., 1994)., the inclusion in sheep diet of pasturentaining moderate levels of condensed tan-such as the short-lived sulla (Hedysarum) and sainfoin (Onobrychis sativa) and the

perennial birdsfoot trefoil (Lotus cornicula-cently gained consensus among scientists (see

ueller-Harvey, 2006). This is due to the fol-itive effects of such species on sheep: higherome circumstances, as reported by Molle etlower ammonia concentration in the rumenet al., 2002a), higher uptake of amino acidsl (Waghorn et al., 1987), overall lower Nnd higher proportion of excreted N in fae-

rine (in sulla: Dentinho et al., 2006), lowerf N and CH4 to atmosphere (Waghorn et al.,roved resilience to gastro-intestinal parasites

and Kyriazakis, 2004), and better animales (review by Ramirez-Restrepo and Berry,ong these forage species, sulla, besides theontent of CT, displays a relatively high NSCe 2), which also explains the good perfor-meat sheep grazing this forage (Douglas et

onses of dairy sheep grazing sulla as mono-in association with grasses (annual ryegrass,idum Gaudin, or Italian ryegrass, Lolium mul-e summarized in Fig. 2. These are results fromSarda and Comisana ewes grazing at moder-stocking densities (2080 ewes/ha) without

tation. They highlight the potential of sullalture to improve milk performance in dairyng spring (mid-late lactation phase), due tointake of this forage as compared with rye-(on average +20%). Moreover, Fig. 2 showsingest more herbage (on average + 10%) andore milk when grazing sulla, associated withses either spatially, as adjacent monoculture,lly, as grazing sequence, than when graz-


Fig. 2. Indexing either Italsulla pasturesarea) grazed iwith 3 or 6 hpaddocks, ii)grass (50:50 biii) sulla mon(Sources: MoBonanno et a

ing grass mlambs fed fwith eitherand feedinggain ratio, tfound that tgrass pastuwith the coet al., 2002preferenceannual ryegwith accesmilkings atpreferencegrazing hotime spentpreferencegrazing timusually fouryegrass asbehaviour hin sheep ruin lambs suand Proventannins, theexploitingfeeds were

In a mfocused onture at flowsheep were

of polyethylene glycol (MW 4000), which specificallybinds to tannins. Interestingly, the latter group exhibitedlonger grazing time (P < 0.07) than that exposed to CT

t.lthougporatet welle legufor da

yegrasr (Trim resuicagooin to

prov(see renergwastecultu

ure (Mconce

lternatraceaairy shg shorm, whto the

lly spas inur CP c

it coed conry metesquitof intake (bars) and milk responses (dots) of ewes graz-ian ryegrass pastures only (baseline, index = 100), or i)in conterminal association with Italian ryegrass (50:50 byn succession (rationed complementary grazing, SURG)access on sulla in the morning and the rest on ryegrasssulla pastures in conterminal association with Italian rye-y area) with free access during the daytime (COMO), andoculture pastures (SUMO). Error bars indicate S.E.M.lle et al., 1998, 2000, 2003; Di Miceli et al., 2005;

l., 2007). Means and S.E.M.

onoculture. Burke et al. (2002b) found thatresh sulla or its mixture (50:50 on DM basis)white clover or lucerne had higher daily gainefficiency, measured as intake to liveweight

han those fed grass-based pastures. They alsohe adjacent monoculture (50:50) of sulla withre gave intermediate results in comparisonrresponding monoculture-based diets (Burkea). Rutter et al. (2005) recently assessed thefor sulla by using adjacent monocultures ofrass and sulla grazed by Sarda lactating sheep

s to the pasture for 22 h daily (except for the8:00 and 16:00). These authors showed that

effecA

incoradapforagturesthe rclovefoliu(MedsainfwhileturesCP tolargemono

mixturea

A(Astefor destinsystecycletionasuchlowewhenrainfondaand sfor sulla was almost complete in the first twours in the morning, but decreased rapidly ason the pasture progressed. On average, thefor sulla, expressed as percentage of totale, was 74%, which is close to the value of 70%nd in sheep grazing white clover-perennialadjacent monocultures (Rutter, 2006). Thisas been attributed to the accumulation of CT

men during the grazing process. For example,bmitted to preference trials indoors, Villalbaza (2002) found that, after the ingestion ofanimals reacted to post-ingestive malaise by

alternative feeding stations where tannin-richless frequent.ore recent study, Giovanetti et al. (2006)

lactating sheep grazing a sulla monocul-ering when CT concentration peaks. Theeither drenched with water or with 100 g/day

positive efftion (e.g. Arotationallymuch milkgrazing sealate-lactatichicory, thdaisy plantal., 2005b)fat-correctegain than tlower milkthe lower Cwith a lowanother dainarium), crumen funvery limiteh sulla is an outstanding legume forage to bed in a grass-based grazing system, it does notto acidic and sandy soils. Thus, alternativemes can be envisaged for inclusion in pas-iry sheep in association with grasses such ass spp. However, species such as the berseemfolium alexandrinum), Persian clover (Tri-pinatum) or the self-regenerating burr medicpolymorpha) are less suitable than sulla orcounter the N excess in lactating sheep diet,iding good herbage production as monocul-eview by Rochon et al., 2004). The very highy ratio of burr medic (Table 2) can bring abouts of N when this species is grazed either as

re (Molle et al., 2002) or grasslegume binaryolle et al., 2007), as revealed by high milk

ntration (often >60 mg/100 ml).ive forage species belonging to the daisye) family can be usefully included in pastureseep. Chicory (Cichorium intybus) is an inter-t-lived perennial forage with a tap rootingich allows this species to extend its growthend of spring, even without irrigation. Nutri-

eaking, this forage is a good source of NSC,lin; it has a relatively low fiber content andontent than legumes in late-spring (Table 2),uld be the only green forage available underditions. Moreover, chicory contains plant sec-abolites (PSM), such as phenolic compoundserpene lactones, which are thought to elicit aect against gastro-intestinal parasite infesta-thanasiadou et al., 2006). Sarda dairy sheepgrazing chicory monocultures yielded as

as those grazing sulla monocultures for threesons (Sitzia et al., 2006). In another study,

on sheep grazed three pasture types based one annual safflower (Carthamus tinctoriusa), and burr medic in MayJune (Landau et. Chicory-grazing sheep produced more 6.5%d milk (P < 0.10) and had higher body weight

he other groups. They also had significantlyurea concentration (MUC), probably due toP content (Table 2). Safflower was associated

er milk protein content. Safflower, as well assy plant, the garland (Chrysanthemum coro-ontains terpenes, which can partially impairction. Terpenes were evoked to explain thed intake and poor performance of sheep fed


fresh garland at flowering stage as sole feed (Addis et al.,2005). In contrast, when this forage species was grazedby late-lactation sheep as a mixture with annual ryegrassand burr medic, garland represented around 30% (DMbasis) of the diet and the resulting milk performance wasas good as that obtained with the binary mixture withoutgarland (Cabiddu et al., 2006a). Results of recent pref-erence trials have clarified that acclimatized sheep cancounteract the effect of a toxic metabolite with that ofanother toxin ingested, provided the detoxifying mech-anism is not the same for both toxins (Iason and Villaba,2006). Examples of complementary toxic PSM are tan-nins and saponins, which explain the bloat curbing effectof tannin-containing legumes. Other classes of comple-mentary toxins are nitrates and oxalates from one hand,tannins, terpenes and oxalates to the other, as reviewedby Provenza et al. (2007).

4. Grazing management of Mediterraneanpastures

The spatial distribution of different forages in a culti-vated pasture (e.g. a grass (G) and a legume (L) in Fig. 3)can rangetures in dicase is a pthe same pwhich animbility is to hfences) behaving accpasture canThis is the

et al., 2001). Each option has its own costs and bene-fits. Scientific evidence has been recently accumulatedsuggesting that, probably due to higher cost of selec-tion, intimate mixtures (case a) tend to reduce intakeand performance of sheep compared with a patchy dis-tribution of the different forages, as found in meat sheepgrazing white clover and perennial ryegrass or subcloverand perennial ryegrass conterminal monocultures (seeChampion et al., 2004 and review by Chapman et al.,2007). Intimate mixtures have complex dynamics thatare often conducive to dominance of one species overthe others and often to weed spreading. Adequate fertil-ization, weed control and alternative uses, such as hayproduction at a specific phenological phase, are all moredifficult to perform under these conditions. Under freechoice of adjacent strips of different species (case b)sheep express their preference until the availability ofthe preferred forage goes down to a switch point, belowwhich the previously less preferred forage begins to con-tribute more to sheep diet, often at the same proportionof the preferred forage (Harvey et al., 2000; Rook etal., 2002; Prache and Damasceno, 2006; Prache et al.,2006). This preferential pasture depletion, although mit-

d alonder-golle e

he andperenntrasttionalup tor-grazss to e

age spefrom intimate mixture (case a) to monocul-fferent paddocks (case d). An intermediateatchy distribution of the two species withinaddock, such as adjacent monocultures toals have free access (case b). Another possi-ave temporary fencing (e.g. electric movable

tween adjacent monocultures, with grazersess to them in succession (case c). Time onbe then split in two or more meal blocks.simplest possible grazing circuit (Dumont

igateto unby MPracwithIn cotradionlyundeacce

Fig. 3. Examples of spatial distribution of two complementary forg the defoliation process, can be conduciverazing of the less preferred forage, as foundt al. (2000) with sulla-annual ryegrass and byDamasceno (2006) and Prache et al. (2006)

nial ryegrass-fescue as paired monocultures., in the grazing circuit (which is the basis ofshepherding), sheep express their preferencean extent, which does not result in marked

ing of the less preferred forage if the time ofach species is adequately tuned. In this case,

cies, e.g. a grass (G) and a legume (L).


the best option is to offer the more preferred forage (e.g.the legume) in the morning and the less preferred for-age (e.g. the grass) in the afternoon (Rutter, 2006). Itis likely that the intake of grass is boosted in the mainevening meprobable acas well asfiber in orduptake of nness and prin simple gPSM-enricwhen PSMare offeredrecent studfoods (incl20% highe(Papachrist

Althougestablishedperiod-to-pthan the otadvantagecific diets(2004) in smixtures, cwas confirdifferent sptwo grassetheir monolonger grazbispecific dferred mon

From anspatial distregarding tcultures (caswards cangrass crop.ever, a mor

of N from tWhatev

grazing memittent appper seasonand all pavariable stadequate stin animal pdue to rotatstocking (sline with re

performance per cow and per unit land were compared(Peyraud and Delaby, 2006).

Rationed grazing (limiting the time for access to thepasture) can also be taken into consideration, to provide

equatay grat on vens. Tr

abouerbag

ents rratione, partance,

hen htricteded neghe incestrictase in

kept aed Coeir 50:

acces

ge Dps witectiveockedntly,

ree ous thegive

in thosimilaria-Rod, 2005re is mlso byby th

ocks.ar miyegrastion al walk

not cosubmior 130996)

effectand mmilk

.al by the post-ingestive effect of legumes (viacretion of volatile fatty acids in rumen pool)

by the need to increase the intake of dietaryer to ruminate it at night, thus postponing theutrients when grazing is impaired by dark-

edator hazard. Interestingly, likewise legumesrasslegume grazing circuits, the intake of

hed foods and total diet are usually higherare offered in the morning than when theyin the afternoon. This has been shown in a

y on sheep where the intake of PSM-enrichedusive of tannins, terpenes or oxalates) wasr in the morning than in the afternoon mealou et al., 2007).h it is possible to alternate monoculturesin permanent paddocks from day-to-day or

eriod (case d), this practice is less preferablehers, due to nutritional reasons. Indeed, theof diverse diets in comparison with monospe-has been recently found by Champion et al.heep grazing grass and legumes as intimateonterminal or separate monocultures. This

med by Cortes et al. (2006) who comparedatial combinations (cases ac in Fig. 3) of

s (L. perenne and Festuca arundinacea) withcultures (case d, in Fig. 3). The authors founding time and higher intake in the sheep offerediets compared with those offered their pre-

oculture (L. perenne).environmental point of view, the proposed

ribution of forages is in general sustainablehe N leaching hazard. By rotating the mono-ses bd), N accumulated underneath legumebe efficiently up-taken by the subsequent

In the case of intimate mixture (case a), how-e immediate and possibly efficient transferhe legume to the grass component is expected.er the spatial distribution of forages, thethod can range from a continuous to an inter-roach. Utmost limits are one day grazing

, under extreme strip-grazing management,sture all season grazing (continuous set orocking). Studies conducted on sheep underocking rates have shown minor improvementerformance (e.g. Marley et al., 2007), if any,ional grazing in comparison with continuousee review by Molle et al., 2004). This is insults from grazing cattle, in which the milk

an adall-deffecditiobringand hnutrithatsheepallowthat wa res

marking tthe rdecrewas

mentor thdailyherbagrouirrespset stnificain thacces

sheepthanwas s

Garcet al.pastubut adailypaddsimilian rlactazontawas

and650al. (1over

gaintrast,damse feeding transition (e.g. from stall-feeding tozing regimens) and to mitigate the tramplinggetation, particularly during wet climate con-ampling and mudding the pasture biomasst soil compaction, impaired water utilizatione growth, and enhancement of water and soilunoff. However, it must also be recognizedd grazing may limit the herbage intake byicularly if herbage sward height or herbageor both, are low. Iason et al. (1999) showederbage sward height was kept as low as 3 cm,time for access to pasture of 9 h/day had aative effect on herbage intake, notwithstand-

rease in intake rate in the sheep submitted toed access regimen. On the other hand, this

intake did not occur when sward heightt 6 cm. Bonanno et al. (2007) fed unsupple-misana dairy sheep on Italian ryegrass, sulla,50 (by area) conterminal monocultures, withs of either 8 or 24 h/day. They found that

MI and milk yield were both higher in theh unconstrained daily access to the pasture,ly of pasture type. Also Latxa milked eweson a natural pasture for 7 h/day showed sig-

although limitedly, higher milk performancet of four years than counterparts allowed topasture for 4 h/day. Since the intake rate inn shorter access time to pasture was highere with longer access time, the herbage intakebetween the two groups (Perojo et al., 2003;riguez and Oregui, 2003; Garcia-Rodriguez). The effect of restricted access time to theodulated not only by herbage accessibilitythe horizontal and vertical distance walkede flock between sheep house and pasture

In milked sheep, Ligios et al. (1997) foundlk performance of Sarda ewes grazing Ital-s with high herbage mass on offer during

nd submitted to 0, 4.5 or 9 km/day of hori-ing. However, in this experiment access timenstrained. Also in sheep stall-fed ad libitumtted for the last 40 days of pregnancy to 0,0 m/day of horizontal walking, Decandia etwere unable to detect any negative carry-of exercise on lamb birth weight, lamb dailyilk yield during the suckling period. In con-yield tended to be higher in the exercized


Stocking rate and density usually have an overwhelm-ing influence on pasture and animal responses as well onthe environmental impact of the whole grazing system.For example, short- to medium-term grazing intensity iscrucial forand, consefor a sensirates for diticularly foal. (2004).agement oor brushlangrazing menutrition, cyear, and mreach theseunder condvegetationsheep grazsate for dec(Agreil et aally heteroby adequalevels muclow-digestsuggestedrotational gcessful inpreservatiostatement ting) are unclassical astocking),of less prethe best anexpensive aherbicide sfeatured byhave sometion aboutresearch an2007) indicstocking deforced to fatrain theisure in sheduring thesuitable fosome adulttures contaThis intens(Provenza

use of electric fences or close shepherding control. Itis important to highlight that specific studies on milkedewes are required before suggesting the field applicationof this technique.

notherng ate obtae, is

ed graultanhas

ing oeterogSpaintain dwith

rmancrobabltypesuate sr diffiry ovenimuthatevre) isiry shis parre grorowthtive toitions,-basedlance.asingively dttle-baizationly rednd DMby (20f the h(Peyration issionspasturfertilire thabala

put froectareced byhe recmodulating herbage allowance, sheep intakequently, milk performance. The basic criteriable choice of grazing methods and stockingfferent types of Mediterranean pastures, par-rage crops, have been discussed by Molle etLess is known about the optimal grazing man-f Mediterranean natural pastures, woodlandd. This would imply the implementation ofthods and pressures, which warrant adequateonservation of pasture resource from year-to-aintenance of pasture biodiversity. Aiming togoals, a method has been recently proposeditions of heterogeneous pasture with woody(Agreil et al., 2004), based on the finding thating shrubby rangeland are able to compen-reased herbaceous biomass by browsing morel., 2005). Providing sheep access to function-geneous plants (inclusive of woody species)te sheperding allowed them to reach intakeh higher than those predicted for such kind ofibility dietary components. Overall, this studythat the implementation of an intermittent orrazing of heterogeneous pastures can be suc-

terms of both sheep nutrition and landscapen. This is in contrast with the widely acceptedhat low-production grazing lands (rough graz-suitable for intensive grazing methods. Thepproach (lenient grazing under continuoushowever, tends to promote higher frequencyferred, so-called unpalatable species eatd leave the rest , which requires the use ofnd/or unsustainable weeding techniques (e.g.preading, mechanical control). Weed species

low palatability often contain PSM thatanti-nutritional effects. Although informa-

this subject is scarce, results of fundamentald some grazing experiments (Provenza et al.,ate that in order to curb this process the instantnsity should be increased, so that sheep aremiliarize with the less palatable forages and

r detoxification systems. The earlier the expo-ep life-time is, the longer the benefits last

ir productive career. Such approach can ber adapting replacement lambs maybe withsheep acting as guide to biodiverse pas-

ining potentially noxious plants or plant parts.ive (short duration) rotational managementet al., 2006) could be realized through the

Aaimiwhilmanc

(mixof simcattleworkon hNWa cer

plingperfobe ptionadeqrathedietaby A

Wpastuof daThispastuthe gsensicondgrassunbaincrepositIn cafertilsharpCP aDelaCP oDMtilizaemisnentof Nis mothe NN inper hreduing tapproach for grazing heterogeneous pasturesmaintaining or improving species diversity,ining economically viable animal perfor-the use of more than one herbivore specieszing or co-grazing). A successful exampleeous and sequential co-grazing of sheep andbeen recently given by Fraser et al. (2007)n temperate herbaceous swards. Differently,eneous pastures including heather brush, in, Celaya et al. (2007) found that, in spite ofietary overlap, sheep showed a better cou-goats than with cattle, in terms of animale. The discrepancy between these studies cany explained by differences in both vegeta-and grazing species or breeds. Defining antocking rate for each co-grazing species iscult and should take into consideration bothrlap and pasture composition, as suggestedand Goetsch (2008, this issue).

er the pasture type (forage crops or natural, grasses usually are the primary componenteep diet under most of grazing conditions.ticularly the case during the early phase ofwth (winter), when grasses overcome by far

rate of legumes and forbs, usually morelow temperature constraints. Under these

applying proper management techniques topastures can mitigate the CP to energy ratioLimiting the level of N fertilization and

the frequency of N applications can influenceairy sheep nutrition and N farm-gate balance.sed grazing systems, a sensible reduction ofrate on a perennial-ryegrass based pasture

uces herbage CP and mildly reduces herbagedigestibilities as reviewed by Peyraud and

06). Milk performance is little affected if theerbage on offer is above or equal to 150 g/kgud and Delaby, 2006). The reduction of N fer-probably the most powerful tool to curb N

in cattle systems based on temperate perma-es. Indeed, the negative effect of a reductionzation level on milk production per unit arean counterbalanced by its positive effects on

nce per unit of area. For example, reducingm 300 to 100 kg/ha lowered the milk yieldby 20%, while the N surplus per hectare was66% (Peyraud and Delaby, 2006). Lengthen-

overy period in a rotationally grazed pasture,


particularly if based on grasses, can cause a mild butsignificant reduction of herbage CP content. Unfortu-nately, data on the implementation of these techniqueson Mediterranean pastures grazed by dairy sheep arelacking. However, it can be argued that there is prob-ably limited scope for reducing N fertilization input tonon-irrigated forage crops or pastures under Mediter-ranean climate. In fact, N fertilization levels usuallyrange between 50 and 100 kg N/ha, because water is themain limiting factor for pasture production. Hence, insheep farming systems, the product of stocking rate bythe length of grazing season, which has a high impact onN surplus per land unit (Peyraud and Delaby, 2006), isexpected to be more associated with cropping intensity,proportion of irrigated land and supplementation levelthan to N supply as fertilizer.

5. Supplementation of grazing sheep

Concenenergy intaing lactatiois concentrtion and peexperimenttrate supplemodest inature focuresponsesmilk net ewere 0.45 (kg concentresponse ofthe manythere are dand geneticsupplemen

Fig. 4. Milk rstall-fed fresh2448%) ordifferent levelet al., 2006b;Belo, 2001).

ferences in herbage mass and allowance as well as thedifferences in the quality of the herbage actually con-sumed by the two species in the reviewed studies.

5.1. Effects of pasture condition on substitutionrates and animal performance

In cattle grazing high quality pastures, the supply ofconcentrates often results in high substitution rates, espe-cially when sward height is high (Bargo et al., 2003;Delaby et al., 2003). As a consequence, the total increasein DMI and energy intake, and the milk response can besmall.

Similarly, in sheep the substitution rate between highquality pastures and concentrate is often high (Bocquieret al., 1988). For example, in a study with Sarda ewes inearly and mid lactation, continuously stocked on Ital-ian ryegrass paddocks maintained at different sward

ts (30, 60 and 90 mm compressed sward height)supplemented with 500 g/day of whole corn perthe substitution rate increased as sward height

ased,5, Mo

decreaased at washerefo

ain residesprote

e dietal mi

age ath statu

. Substicontinuheights

meter (Mtrates often represent a high proportion ofke in grazing dairy ewes, particularly dur-n, but the main question is: how importantate supplementation for grazing sheep nutri-rformance? By pooling the results of differents on dairy sheep, the milk response to concen-mentation was evident (Fig. 4) but relativelycomparison with estimates based on liter-

sed on dairy cattle. For example, the milkof dairy cattle and dairy sheep, in terms ofnergy (Mcal) output per kg of concentrate,Delaby et al., 2003) and 0.30 Mcal of milk perrate (this review), respectively, being the milkcattle 20% higher than that of sheep. Among

reasons that could explain this difference,ifferences in size, morphology, physiologymerit between these species, differences in

tation level and quality of concentrates, dif-

esponse (g milk/kg concentrate) of dairy ewes grazing orforages, supplemented with fibrous (NDF 2852%, NSC

starchy (NDF 2128%, NSC 4860%) concentrates ats (From Addis et al., 2005; Avondo et al., 1995; CabidduDecandia et al., 2007a; DUrso et al., 1993; Marques and

heighandewe,

incre(Fig.to aincreeffec

Tthe mbe, bmilkin thoptimwasthealt

Fig. 5ewes

swardgrassunder some circumstances exceeding 100%lle et al., 1997). This effect was associatedse of the milk response as the sward heightnd lactation progressed, although the latter

confounded with pasture maturity.re, for ewes grazing good-quality pastures,ole of concentrate supplementation shouldthat of increasing milk yield and sometimes

in, to improve the balance among nutrientsand to synchronize energy and N supply forcrobial growth. This would in turn reduce Nanimal scale and improve or maintain thes of the ewe. Substitution of herbage with

tution rate of grazed herbage by corn grain (%) in dairyously stocked on Italian ryegrass pastures at different. The sward height was measured by a weighed squareolle et al., 1997).


concentrate can also be used to increase stocking ratesor lengthen the grazing season where pasture availabilityis limited. These goals can be achieved by defining theappropriate dose, quality and distribution techniques ofconcentrate

5.2. Interaconcentrat

The abscentrates cgenetic meis a generagrazing shecentrate suby the stagmerit of thand Delabylactation thlactation prhormonal stioning ofconcentratethan milkmechanismmerit cowsSimilarly, Ktution rateslow geneticsubjected tdairy cowsof sheep codue to diffe

5.3. Effectsupplemen

The defican be comconcentratethe datasetconcentrate400 g/day,while as ththe milk resconcentrateBargo etmilk yield.pulp and splements (ryegrass, shardly fou

although milk yield tended to be higher in the fibrousconcentrates than in the starchy ones (Decandia et al.,2007a).

A negative role of starchy concentrates in diets offereditum

nas etsheepdy fa

gluconin star, in coin actiuct. Inlatedin mira et arly-lacates is; Bovebecaulevelsof per).he use

in grtion),e asnt of

is avaifiber

p supps menide Ncase, turtheralso bs and,icrobiage intivelylemennitrognitrog

lement easyastureignifiates rilemenproteigradabwas es.

ction between animal characteristics ande supplementation

olute response to supplementation with con-an vary depending, among others, on therit and lactation stage of the sheep. Therel shortage of data on these relationships inep. In dairy cattle, the milk response to con-

pplementation seems to be affected negativelye of lactation and positively by the genetic

e animals, as reviewed by Bargo et al. (2003)et al. (2003). The lower milk response in late-an in early-lactation is probably because asogresses there is a homeorhetic change in thetatus of the animals, which favors the parti-dietary energy, especially that from starchys, towards body reserves deposition ratherproduction (Peel and Bauman, 1987). This

seems to be more evident in low genetic(Peel and Bauman, 1987; Bargo et al., 2003).ennedy et al. (2003) observed lower substi-and higher milk responses in high than inmerit cows. Since dairy sheep have not been

o the same intense genetic selection applied to, it is likely that the 20% lower milk responsempared to cattle previously reported is mainlyrences in genetic merit.

s of quantity and quality of concentratetation on sheep performance

nition of the optimal dose of concentratesplicated by the possible interaction betweendose and concentrate quality. According to

summarized in Fig. 4, as the supply of starchys increased from less than 300 g/day to above

the milk response of ewes actually decreased,e supply of fibrous concentrates increased,ponse increased. In dairy cows, when starchys were compared with fibrous concentrates,

al. (2003) reported inconsistent effects onSimilarly, when comparing barley, corn, beetoybean hulls-based concentrates fed as sup-600 g/day) to lactating sheep grazing Italianignificant differences among treatments werend for herbage intake and milk production,

ad lib(Canthatto bolaterichfiberinsulprodstimuewes

Bovein eacentr2003ablyhighness

1987T

riskylactacan bamou

turetheirshee

Aprovthiscan fmaythesiof mherbnegasuppown

theirsuppis noing pwas s

centrsuppableundeThisto stall-fed mid- and late-lactation dairy sheepal., 2002, 2003) was explained by the fact

are proner than dairy cows to divert energyt deposition when concentrates that stimu-eogenesis and insulin response (e.g. thosech) are used. Concentrates rich in digestiblentrast, do not stimulate gluconeogenesis andon, because acetate is their main fermentationfact, in many experiments such concentratesmilk yield more than starchy concentrates ind- or late-lactation (Cannas et al., 2002, 2003;l., 2004; Zenou and Miron, 2005). Differently,tation ewes, the positive effect of fibrous con-absent or less evident (Cannas et al., 2002,

ra et al., 2004; Zenou and Miron, 2005), prob-se in periods of negative energy balance theof growth hormone reduce the responsive-

ipheral tissues to insulin (Peel and Bauman,

of high levels of starch supplement can beazing sheep in late-winter or spring (mid-since grass NDF can still be low, while WSChigh as 20% DM. The provision of a smallhay (ca. 300 g DM per ewe), even when pas-lable, is considered a way to let animal meetrequirements and to prevent sub-acidosis inlemented with starchy concentrates.tioned before, high-quality pastures generallyintake in excess to ruminal requirements. Inhe utilization of concentrate rich in proteinincrease this unbalance. Excessive N intakee associated with inefficient microbial syn-sometimes, with insufficient intestinal supplyal protein. Avondo et al. (2002) reported thattake in ewes grazing pastures rich in CP wascorrelated with the concentration of CP in thets, suggesting that ewes are able to sense theiren status and self-regulate, when allowed,en intake. Unfortunately, the effect of CP

tation on sheep grazing good-quality pastureto predict. Indeed, in lactating ewes graz-

s fairly rich in CP (up to 19% CP), milk yieldcantly higher in ewes supplemented with con-ch in rumen degradable protein than in thoseted with concentrates having lower degrad-n content, while there were no effects of thele protein supply (Wilkinson et al., 2000).xplained by the fact that the ratio between


rumen degradable protein and fermentable energy ofthe pasture was too low to maximize microbial activ-ity. However, even the estimation of this ratio mightnot always be sufficient to explain the complex inter-action betwproductionconcentratiquadratic rmatter (andegradableal., 2005a)

In orderCP in sheesupplemencontainingNH3-releasoils). Howscanty forDM of queplementarymilk yieldtrol dairytannin-fedSimilarly,supplemeneffects on awere obser

In contrthe rumen,rich concenexample, wments of spastures ofthe soybeasupplemen

5.4. Groupanimal var

Mediumby high vaity in lactavary markebased systereceive theThe mostthat the mthe least pthe milk iduction levflock (Bocmals reduc

consequences for the farm. In addition, animals whichare too fat or too thin at mating display a lower fertilityand prolificacy than those with adequate body condition(Rassu et al., 2004). For these reasons, a subdivision

e flocinto

een caariabbeen

ns (e.grelev

ncentn themoun

t, com, whie to c

p.our

ng ewia to bore gr(199

p prefwes w

ts usinduringked ane body995).ps migamongilk proeate suof lactive ore apvariatia are

ctationpract

ved inthe f

ividedfferenng onh diffeetimesd, beip (leadld be mpplemeen rumen N and energy supply and milk. For example, in Assaf ewes milk proteinon, but not milk or casein yield showed aesponse to ratios of rumen degradable organicestimate of rumen fermentable energy) toprotein ranging from 4.5 to 5.3 (Landau et

.to mitigate the unbalance between energy andp grazing lush pasture, one could think aboutting them with small amounts of concentratestannins (e.g. chestnut tannins) or other rumene modulating agents (e.g. terpenes, essentialever, information about this subject is stillgrazing sheep. For example, when 90 g/kgbracho soluble tannins were added to a sup-concentrate fed at a level of 450 g DM/day,did not differ between tannin-fed and con-

ewes, while milk fat content was lower inewes (Garcia-Rodriguez and Oregui, 2003).when Merino lambs fed pelleted diets wereted with 20 g/kg DM of chestnut tannins, noverage daily gain and carcass characteristicsved (Frutos et al., 2004).ast, when there is a clear rumen N shortage inthe supplementation of the diet with protein-trates generally induces positive effects. Forhen Sarda ewes fed iso-energetic supple-

oybean meal or corn grain grazed maturelow N content, pasture intake was higher withn meal supplement than with the corn graint (Molle et al., 1995).

feeding and strategies to account foriability

-large flocks of dairy sheep are characterizedriability in milk yield and a certain variabil-tion stage. Thus nutrient requirements candly within the flock. However, in pasture-ms usually all the animals of the same flocksame amounts of concentrate at milkings.

frequent result of this feeding technique isost productive animals are under fed, whileroductive ones are over fed. Since most ofs produced by the ewes which have pro-els higher than the mean production of thequier et al., 1995), underfeeding these ani-es their milk yield, with serious economic

of thtakenhas bmal vhaveratiomuchto cowithithe aextensheepforaggrou

Tograzicriteror m

et al.set uthe etriplethatchecor thal., 1groution

Mto crstageobjeca mo

largecriterof la

Ininvolwhensubdin digraziwhicSomaheagroushouof suk in two or more feeding groups should beconsideration. However, very little researchrried out on the strategies to account for ani-

ility in grazing sheep. Even if several studiescarried out on dairy cattle fed total mixed. Sniffen et al., 1993), this research is notant for grazing sheep, for which the forage

rate ratio varies from one animal to anothersame flock. This is because variations in

t of concentrate supplied can be, to a certainpensated by variations in pasture intake in

le in dairy cows fed total mixed rations theoncentrate ratio is fixed within each feeding

knowledge, supplementation strategies fores which account for animal variability ande used for the division of the flock into two

oups have been addressed only by Bocquier5). They reported that the groups should beerably during late pregnancy, by separatingith single birth from those with twin andg ecographic diagnosis. They also suggestedlactation the groups should be periodically

d reorganized considering the milk producedcondition score of the animals (Bocquier et

However, the frequent reorganization of theht pose problems of competition and adapta-sheep, with possible losses of milk.duction is probably the easiest criteria to usebgroups in flocks with animals in the sametation. It also represents the main economicf the farm. Body condition score could be

propriate criteria in flocks characterized byion in the stage of lactation. Anyhow, the twocorrelated, especially after the first months.ical terms, there are no particular problems

dividing the flock in two or more groups,arm is well organized and the pastures arein paddocks. Different groups can be kept

t paddocks, with the most productive ewesthe best pastures, for the whole period forrent feeding regimes are deemed necessary.the high yielding group grazes the paddocks

ng followed by the less productive or dryers-followers grazing technique). The groupsilked separately and different doses or types

ents should be supplied to each group.


This is not the case if sheep graze open lands andpasture partitioning is not feasible. In this situation, onepossible technique is to graze sheep as a single flockand to subdivide it in two or more productive groups,identified bbefore eacwith exitsdependingdifferent grappropriatefies grazingbefore eachis increasiwill probab

A thirdmilking pacan supplythe milk prreported thnot affect mgroup, butper lactatio

5.5. Choicoptimal nu

While theffects of dof concentmuch lessof feedingresponses.

In sheepbial yield aof energynutrients wmarkedly ienergy andthat the synof stall-fedcantly reduday. A marreduction ifed male shor 2 h befotation 4 orconclusionof energy ainfluence mfeeding schthe N excesmilk urea c

Even though in literature milk yield and the health sta-tus of the animals are not often affected by N excesses,it should be noticed that results of short-term experi-ments might not fully represent what happens in sheep

cted tany fas in thence o, withates w, with

beforeorma

t fieldng timazingystemased opredicished aof cong ewictionsracy thion raptimas.

Effecttion a

s prevncentrreals,ances

eep. Gp fed pentratiencythan

ndia ets in gn leveible restudi

n the gicit thobserlthougSC gethis ef

levels,y marks of different colours on the fleece,h milking. This requires the use of a corralleading the ewes into different sheepfoldson the colours marked on their fleece. Theoups should be milked separately and fed thedietary supplements. This technique simpli-management but requires additional labour

milking. As electronic identification of sheepng, automatic barrier management systemsly appear in the next years.option, valid for all types of farms, is to userlours equipped with electronic feeders thatindividual doses of concentrate, according tooduction of each ewe. Bocquier et al. (1995)at the utilization of this type of equipment did

ilk yield, compared to ewes kept in a singleallowed to save 50 kg of concentrate per ewen.

e of the concentrate feeding time fortrient synchronization

e literature is rich in experiments testing theifferent doses and, to a lesser extent, types

rates on the performance of grazing animals,research has been carried out on the effectstime and nutrient synchronization on such

, Henning et al. (1993) showed that micro-nd efficiency were not affected by the degreeand N synchronization when pulse doses ofere supplied, while microbial activity was

mproved when there was a steady supply ofN in the rumen. Witt et al. (2000) observedchronization of dietary energy and N supplyewes did not improve milk yield but signifi-ced plasma urea concentration throughout theked improvement in microbial efficiency andn rumen ammonia was observed in pasture-eep when barley grains were fed just before

re grazing compared with barley supplemen-6 h before grazing (Trevaskis et al., 2001). In, it seems that improving the synchronizationnd N availability is not expected to stronglyilk yield. Nevertheless, adequate concentrateedules are beneficial because they can reduceses, and thus rumen ammonia, and blood andoncentrations.

subjein mmentincidcases

centra dayjusttwo n

Afeediin gring sare bsuchpubllevelgrazipredaccu

stitutthe omeal

5.6.pollu

Aof coon ce

allowby shsheeconc

efficidietsDecaresultatiopossthesetion ito ellevel

Aof Nleveltiono N overload for months, as it often occursrms. In such conditions, marked improve-

e nutritional status of dairy sheep (with lowerf diarrhea induced by N-excess and, in somehigher milk yield) were observed when con-ere distributed three times instead of twiceone distribution of concentrate being givengrazing on lush pastures in addition to the

lly given at milking time (Cannas, 2004).level, it is hard to achieve the appropriatee and level of concentrate supplementation

ruminants on an empirical basis. Most feed-s and diet-balancing systems for ruminantsn static models and thus are not able to maketions. Recently, Imamidoost and Cant (2005)dynamic model to estimate feeding time and

ncentrate supplementation in high-producinges. Despite the low accuracy of some of its, this model was able to predict with goode variation of the pasture to concentrate sub-

te, as the supply of concentrate increased, andl number and time of supply of concentrate

of concentrate supplementation on Nt farm scale

iously mentioned, increasing the proportionates in sheep diets, particularly in those basedis an effective way to balance energy and Nand thus curb the release of N in the excretaiovanetti et al. (2007a) found that lactatingelleted diets ad libitum had lower milk ureaon and N excretion and higher N utilization(i.e. N in milk/N intake) with starch-basedwith digestible fiber-based diets. However,t al. (2007a) were unable to confirm theserazing sheep offered a moderate supplemen-l (600 g/day) of the same pellets. One of theasons for the apparent contradiction betweenes was that although the level of supplementa-razing study was relevant, it was not sufficient

e effects of dietary carbohydrate source andved in the previous study.h at animal scale the use of concentrates rich

nerally limits N release, at paddock and farmfect can be smoothed or, at high supplementa-sometimes counterbalanced by the probable


increase of the stocking rate allowed by the herbage-saving effect of the supplement. This could result inhigher N surplus per land unit (Peyraud and Delaby,2006). Concentrates are usually extra-farm inputs, buteven whenadvantagebased on ir

On thethat improvavailabilitysystem leve

As mensupplemenat animal bnut tannin,benefit of thtion, even ta slight reda limited ineffect mighconcentrati

The antseveral pathstrated (Wamuch reseatest the abilproductionwhile in shto reduce adeaminatioobserved inably as a rthe adaptatal., 2007).

The actcompared tprotozoal asome bactetion of Yuccto the diet onia concenincreased mal., 2006).of Y. schidito diets basand volatilfiber digestion of saprumen amm

(Santoso ements the aconcentrati

microbial protein synthesis and efficiency and sheep per-formance, in some cases it reduced microbial proteinsynthesis and efficiency (Wallace, 2004). As stated byWallace (2004), the effects of saponins on ruminants are

lex anhesetheir

onitop

effecgraz

veme

g a sted byehavire varlowanconsu

pectedists ofor simas gl

S, 19ld bespecierent s). Undof woe avaiicularltake dng tacass avbasedologielimin, 2007deed,m focnas etng shen sysssionharacweig

bles rtion (A, for gheep iromisproduced on the farm the environmentalof their use is questionable, particularly whenrigated highly fertilized maize.contrary, the concentrate supply techniquese the synchronization of energy and proteinmight reduce N waste at both animal andl.

tioned above, small amounts of tannins viat could be utilized to decrease the N wastageut also system scale. Dosing lambs with chest-Sliwinski et al. (2002) confirmed the possibleis approach to reduce rumen NH3 concentra-

hough this reduction was associated with onlyuction of urine N losses (as % of N intake) andcrease of N utilization efficiency. This uncleart have been due to the very low tannin dietaryons used in the experiment (12 g/kg DM).imicrobial activity of essential oils againstogenic bacteria has been extensively demon-llace, 2004). For this reason, in the last yearsrch has been carried out in vitro and in vivo toity of essential oils to reduce rumen ammoniain protein-rich diets. In general, it seems that

ort-term studies many essential oils were ablemmonia production in vitro, by inhibiting then of amino acids, the same effects were notin vitro long-term studies or in vivo, prob-

esult of shifts of microbial populations or ofion of microbes to essential oils (Benchaar et

ion of saponins seems to be more effective,o that of essential oils, mainly for their anti-ctivity and for their selective action againstrial species (Wallace, 2004). Indeed, the addi-a schidigera, a plant species rich in saponins,f wethers significantly reduced rumen ammo-tration and urinary N excretion, while iticrobial N supply and efficiency (Santoso et

Similarly, in wethers the addition of extractsgera or Q. saponaria, both rich in saponins,ed on ryegrass hay reduced rumen ammonia

e fatty acids concentrations without affectingtibility (Pen et al., 2007). In goats, the addi-onins from Biophytum petersianum reducedonia concentration and urinary N excretion

t al., 2007). However, while in most experi-ddition of saponins reduced rumen ammoniaon and urinary N excretion and improved

compFor twhen

6. Mshee

Tosheepachielectiningestive bpastuor altimeof excons

turesusedNRCshouvore

diffe2002siveof th(partof ingrazibiomalsotechnby pret al.

Insyste(Cangrazidictioregretion cbodyvariadirec2005ing sare pd depend on the diet and the saponins used.reasons, more research is needed to clarifyuse in the field is advantageous.

ring nutritional unbalance in grazing

tively manage the complexity of the dairying systems in the light of new scientificnts, decision support tools are required. Col-ample which is representative of the dietsheep is a challenge because of their selec-

our. Measurements or subjective estimates ofiables, such as the sward height, herbage massce, and pasture botanical composition, areming and do not provide an accurate picture

grazing system response unless the pasturehomogeneous, actively growing monocul-ple mixtures. Residual sward height is oftenobal indicator of pasture availability (e.g.97), but its accuracy for a specific pastureadjusted to the animal genotype, as herbi-s, and breeds with different sizes often haveward height optimal profile (Osoro et al.,er heterogeneous pasture conditions inclu-

ody vegetation subjective visual assessmentlability of different putative feeding sourcesy the parts of plants which make the mosturing paddock depletion) is pivotal to thetic (Agreil et al., 2004). Evaluation of theailable in paddocks and its quality could bein the future on on-farm or remote-imaging

es (e.g. Shut et al., 2005), as suggested alsoary results on Mediterranean pastures (Fava).although a well-based mechanistic feeding

used on dairy sheep has been recently releasedal., 2004), its ability to predict intake of

ep has to be improved. Novel empirical pre-tems of small ruminant intakes based onanalysis, using pasture and animal produc-teristics, such as milk yield and composition,ht and body condition score, as independentepresent an important step forward in thisvondo et al., 2002, for sheep; Decandia et al.,

oats). Mechanistic prediction systems of graz-ntake such as that by Baumont et al. (2004)ing for a more significant and long-lasting


scientific advancement but, in order to become practi-cal for dairy sheep in Mediterranean environment, theyneed to integrate appropriate key relationships, whichare currently lacking.

Milk urea concentration (MUC) is an effective gaugeof protein nutrition in grazing sheep, as previouslyfound by Cannas et al. (1998) under confinement con-ditions. In a 3-year study, lactating sheep grazed threebinary mixtures consisting of annual ryegrass, and eitherburr medic, subclover (Trifolium subterraneum) or sulla.Pooling data (N = 72) of the average group dietary CPpercentage and plotting them against the average MUC,a linear relationship which explained 0.55 of total vari-ation was found (Molle et al., 2007). According to thisequation, for CP dietary levels ranging between 15 and20% DM, MUC varies from 32 to 43 mg/100 ml. Inthe same sbetween C

CPNEL

(g/M

R2 = 0.55

A moreMUC is thCP and NECP concenlevel (Giovthere is aregressiongests that rehave similaGiovanettiis well relaefficiency.will makeing, besidesheep indube risky o

Fig. 6. Relatisheep (Giova

age) and environmental conditions wherein they werebuilt.

While the above results are promising, monitor-ing pasture intake and quality by analyzing chemicalattributessamples arsentative oThe organhas been shnitrogen comation encexploited wtrometry (Fand Stuth (FNIRS mepredict a w

cteris., 200nfined(R2 > 0andiamodeand a

, in paccura

CP, i.eicted (mine998) sge ofdiffere

andneral,polateon samlishedentratens in w

thanies useoats Lon oftibilitlationIn oth

razingmpassompolatedandauS equin gtudy a moderately strict linear relationshipP/NEL and milk urea was found:

cal NEL)=1.62 MUC(mg/100 ml) + 68.44;

.

fundamental research has confirmed thate best single predictor of the ratio betweenL, since the relationship between MUC andtration is modulated by the dietary energyanetti et al., 2007b, Fig. 6). Interestingly,good agreement between the slope of theabove reported and that of Fig. 6, which sug-lationships across different feeding regimensr trends. A side-achievement of the study byet al. (2007a) has been the finding that MUCted with N excretion as urine and N utilizationValidating this relationship in grazing sheepMUC an outstanding variable for monitor-s nutrition, the environmental impact of dairystry. However, its practical application couldutside the specific genetic (animal and for-

onship between CP/NEL and milk urea in stall fed dairynetti et al., 2007b).

charaet alin cosion(Decwith0.90)tionsand aublepreddeteral., 1centafourof 5%in geextrabratiestabconc

ditiomore

specon gidatidigespopution.for genco

diet ccalcuby LFNIRcomeof faeces holds potential because faecale easily obtained, and they are always repre-f the animal and the diet selected on pasture.ic matter digestibility of a tropical pastureown to be correlated (R2 = 0.74) with faecalncentration (Boval et al., 2003). The infor-ompassed in faecal samples has been furtherhen faecal Near Infrared Reflectance Spec-NIRS) pioneered at Texas A&M by Lyons1992) for cattle was applied to sheep. In thethodology, chemometric analysis enables toide array of dietary attributes, relying on thetics of faecal spectra (see review by Landau6). The technology has allowed to predict

sheep: dietary CP content with high preci-.95) and accuracy in a range between 0.24%

et al., 2007b) and 1.1% (Li et al., 2007); OMDrate precision (R2 in a range between 0.80 andccuracy between 1.5% and 3.4%; fiber frac-rticular lignin with good precision (R2 = 0.96)cy (0.27%). In addition, ADF and NDF insol-. dietary CP of low availability, could also beDecandia et al., 2007b). The first attempt tobotanical composition by FNIRS (Walker ethowed potential to estimate the dietary per-Euphorbia esula L. in sheep fed diets withnt forage ingredients, featuring an accuracy

a R2 value of 0.96. However, NIRS equationsand FNIRS equations in particular, cannot bed beyond the conditions represented in cali-ples (Coleman et al., 1995). FNIRS equationsfor goats fed three species of browse and(Landau et al., 2004) were not robust to con-hich free-ranging goats ingested diets with

ten ingredients, including the three browsed for calibrations. However, in a further studyandau et al. (2005b) found that external val-FNIRS equations of dietary CP and in vitroy was successful if the structure of predictedwas similar to that of calibrating popula-er words, FNIRS can be successfully usedunder farm conditions only if a wide dataset

ing a wide array of botanical and chemicalsition is available, from which calibrations aread hoc to assess dietary attributes (see reviewet al., 2008). The complexity of establishingations under grazing situations has been over-razing goats by using feeding observational


data (e.g. qualitative and quantitative bite counting) asreference values to calibrate equations (Glasser et al., inpress) and similar work needs to be done for dairy sheep.To summarize, the FNIRS method is non-invasive andenvironmental friendly, and provides quickly accurateinformation as long as calibrations are judiciously used.

7. Practical application and future researchneeds

A general strategy for feeding dairy sheep on pastureentails an adequate choice of forages as well as effectivegrazing and supplementation management. A detaileddescription of year-long feeding models under differ-ent scenarios is beyond the scope of this review, sinceaspects such as the effect of nutrition on reproductiveperformance were deliberately overlooked here and arediscussed elsewhere (e.g. review by Rassu et al., 2004).However, for practical purposes, an outline of a generalfeeding strategy to be implemented on field is sketchedin Fig. 7. It depicts the management of autumn-lambingdairy sheep in a semi-intensive grazing system based onnon-irrigated Mediterranean forages. For simplification

reasons, the pasture growth curve shown in the bodyof Fig. 7 encompasses both natural pasture and foragecrops, although the specific growth profile of these pas-tures does not usually overlap (e.g. Guerin and Gautier,2004). Pasture growth refers to two main classes, i.e.grass and other species (legumes and forbs such asAsteraceae), highlighting the need for a diverse dietthroughout the production cycle. These classes representforage species, which have complementary nutritionalvalues and contain moderate levels of a variety of sec-ondary compounds, referred to as antinutritional untilrecently. In practice, a high-quality grass such as Ital-ian ryegrass could be complemented by legumes likesulla or sainfoin and Asteraceae like chicory. Establish-ing these forage crops can be of interest for non-irrigatedfarms aimed at medium to high production per unit ofland (about 7501500 kg/ha of milk). A prerequisite forchoosing forage species is that under local conditionsthey show adequate agronomic performance, namelybiomass production and its distribution within and acrossgrazing seasons (persistency). Attention should also bedirected to the economic viability of forages at farm scaleand their effect on food quality, inclusive of nutracines

Fig. 7. Outlin p graziData and curv ed on dpulps.e of a general strategy for the feeding of autumn-lambing dairy sheees are only indicative. Fibrous concentrates refer to concentrates basng semi-intensive, non-irrigated Mediterranean forages.igestible fiber sources such as soy hulls and sugar beet


(i.e. food components having putative beneficial effectson consumers health, such as CLA and polyunsaturatedfatty acids) and sensory properties. The use of forageswith double purpose such as those adequate for bothgrazing anter cerealsthe importabove comor grazinglactating shspecies. Ingiven to sh

The grafor guidancpresence ofarm area).with hay amilk yieldthe stockinpasture duFig. 7). Digter milk rsheep, whibased on ldrated lucestanding-h

Tacticsegy to the eshould betools descrcondition s

Althouggrazing maareas are stbetween swsheep has ba narrow se

et al., 2004grazing ciring and shebeen suggevirtual fencdistant scieization inmanagemeto lead flocing circuit bthe acoustiand Rutter,direction. SN availabition time o

also warranted, since data on sheep are scanty. The sameapplies to the use of supplementary tannins, essential oilsor other NH3-binding agents. All these areas urge newresearch efforts if the release of N to the environment

o be eesidesso reqbility.ase anroadegemenolog

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, M., Caolle, G.d differ

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., 2002.es in se, 2752, F., Mview: psture. Jont, R.,echanisating swchnol. 1aar, C.,

., McAlrived esed Sci.d hay or silage making and, possibly, win-should be kept in mind in order to decreaseof extra-farm feed resources. The offer of theplementary forages, as adjacent monoculturescircuits, is more beneficial for the nutrition ofeep than that intimate mixtures of the sameany case, some degree of freedom should beeep in order to let them adjust their diets.zing methods described in Fig. 7, which aree only, basically refer to systems where the

f forage crops is relevant (at least 30% of theEven when supplementation of grazing sheepnd concentrates based on cereals increasesonly slightly, it is often helpful for keepingg rate above the carrying capacity allowed byring slow growing periods (autumnwinter,estible fiber-based concentrates provide bet-

esponses, particularly in mid-late lactationle high to medium protein-rich concentratesegumes such as soybean or peas or dehy-rne can compensate for the CP shortage in

ay and stubbles during summer (Fig. 7).aimed at adapting the above general strat-ver-changing climate and pasture conditionsbased on a sensible use of the monitoringibed in Section 6, such as sward height, bodycore and milk urea.h progress has been made in the feeding andnagement of dairy sheep, relevant researchill undermined. For example, the relationshipard height and intake or performance of dairyeen explored only for a few forages and undert of grazing conditions (see review by Molle). There is also urgent need of research on

cuits for dairy sheep and automated monitor-pherding of flocks. Remote shepherding hassted by the use of remote-controlled gates oring (Anderson, 2007). An intriguing but alsontific target is the decoding of sheep vocal-

order to monitor and possibly control flocknt. For example, in the future we might be ableks from milk-shed and back along the graz-y the re-play of key-bees. Advancements in

c monitoring of feeding behaviour (e.g. Ungar2006) could be regarded as a first step in thattudies on the synchronization of energy and

lity in the rumen by tuning the administra-f the concentrate relative to grazing time are

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hors gratefully acknowledge the skilful assis-. Ana Helena Dias Francesconi for editing the.

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biddu, A., Pinna, G., Decandia, M., Piredda, G., Pirisi, A.,, 2005. Milk and cheese fatty acid composition of sheepent Mediterranean forages with particular reference totrans11. J. Dairy Sci. 88, 34433454.euret, M., Vincent, M., 2004. Grenouille: une methoder les ressources alimentaires pour des ovins sur milieuxailles. Fourrages 180, 467481.itz, H., Meuret, M., 2005. Maintenance of daily intakeite mass diversity adjustment in sheep grazing on het-s and variable vegetation. Appl. Anim. Behav. Sci. 91,

N., 2007. Virtual fencing past, present and future. Thed Journal 29, 6578.Goetsch, A.L., 2008. Co-grazing of sheep and goats:nd constraints. Small Rumin. Res. 77, 127145., S., Gray, D., Younie, D., Tzamoloukas, O., Jackson,akis, I., 2006. The use of chicory for parasite control ines and their lambs. Parasitology 134, 299307.icitra, G., Bognanno, M., Keshtkaran, A.N., Marletta, D.,., 1995. Effects of the type and level of supplementation

g behaviour of lactating ewes in a Mediterranean naturalivest. Prod. Sci. 44, 237244.Bordonaro, S., Marletta, D., Guastalla, A.M., DUrso,A simple model to predict the herbage intake of grazingmi-extensive Mediterranean systems. Livest. Prod. Sci.83.uller, L.D., Kolver, E.S., Delahoy, J.E., 2003. Invitedroduction and digestion of supplemented dairy cows on. Dairy Sci. 86, 142.

Cohen-Salmon, D., Prache, S., Sauvant, D., 2004. Atic model of intake and grazing behaviour in sheep inte-ard architecture and animal decisions. Anim. Feed Sci.12, 528.Calsamiglia, S., Chaves, A.V., Fraser, G.R., Colombatto,lister, T.A., Beauchemin, K.A., 2007. A review of plant-sential oils in ruminant nutrition and production. Anim.Technol., doi:10.1016/j.anifeedsci.2007.04.014.


Bertoni, G., 1995. Principali conseguenze negative degli inadeguatiapporti proteici e relazioni con lurea. In: Bertoni, G. (Ed.), LUreanel Latte: Cause di Variazione, Conseguenze per lAnimale eMezzi Correttivi. Associazione Italiana Allevatori, Rome, Italy,pp. 1131

Bocquier, F., Tdes ovins.Caprins. I

Bocquier, F.,des brebis1928.

Bonanno, A.,G., Giamb8 or 24 hSci. Eur. 1

Boval, M., Arfaecal nitrtropical h

Bovera, F., CR., Zicarnon-strucperforman6170.

Branca, A., MShort-termovulationewes. Ani

Burke, J.L.,of sulla (Hlucerne fo

Burke, J.L., Wpotential o25, 2528

Cabiddu, A.,G., 2005.of benefic169180.

Cabiddu, A.,Pirisi, A.,plant (Cheffect onreference

Cabiddu, A.,G., Pirisi,concentrafed Meditgated lino292311.

Cannas, A., 20Sheep Nu79108.

Cannas, A., Pof dietaryin dairy ew

Cannas, A.,improve lthe 8th Gpp. 1759

Cannas, A., CEffects ofin vivo dAbstracts

Cannas, A., Tedeschi, L.O., Fox, D.G., Pell, A.N., Van Soest, P.J., 2004.A mechanistic model for predicting the nutrient requirements andfeed biological values for sheep. J. Anim. Sci. 82, 149169.

Celaya, R., Olivan, M., Ferreira, L.M.M., Martinez, A., Gracia, U.,oro, K.d perfoarginalpion, Rect of s

g behav76.an, D.

M., Venpacts o

take, anan, S.W

take by: Owenstake in F, C., Da

eir intakim. Scdia, M.las, G.,elques prmanceminantdia, M.ing goathe 20tdia, M.., Mollentrate oazing ewthe 14td, Planbstract)dia, M., Landaion andthe 12tessalony, L., Pvachesho, M.

fect ofedysaru21st Gasslandceli, G05. Thee: the e: OMarassland511 (Aas, G.BW., 199rnicularcass faric. ReH., Wtford, K24.heriez, M., Prache, S., Brelurut, A., 1988. AlimentationIn: Jarrige, R. (Ed.), Alimentation des Bovins, Ovins &

NRA Pub., pp. 249279.Guillouet, P., Barillet, F., 1995. Alimentation hivernalelaitie`res: interet de la mise en lots. Prod. Anim. 8 (1),

Di Grigoli, A., Vergetto, D., Tornambe`, G., Di Miceli,alvo, D., 2007. Grazing sulla and/or ryegrass forage fordaily. 1. Effects on ewes feeding behaviour. Grassland2, 208211.chime`de, H., Fleury, J., Xande, A., 2003. The ability ofogen to predict digestibility for goats and sheep fed witherbage. J. Agric. Sci. (Camb.) 140, 443450.

utrignelli, M.I., Calabro`, S., Piccolo, G., Tudisco,elli, F., Piccolo, V., Infascelli, F., 2004. Effects oftural carbohydrate dietary content on the productiveces of Sarda primiparous ewes. Ital. J. Anim. Sci. 3,

olle, G., Sitzia, M., Decandia, M., Landau, S., 2000.dietary effects on reproductive wastage after induced

and artificial insemination in primiparous lactating Sardam. Reprod. Sci. 58, 5971.Waghorn, G.C., Brookes, I.M., 2002a. An evaluationedysarum coronarium) with pasture, white clover and

r lambs. Proc. N Z Soc. Anim. Prod. 62, 152156.aghorn, G.C., McNabb, W.C., Brookes, I.M., 2002b. Thef sulla in pasture-based systems. Anim. Product. Austr.

.Decandia, M., Addis, M., Piredda, G., Pirisi, A., Molle,Managing Mediterranean pastures to enhance the levelial fatty acids in sheep milk. Small Rumin. Res. 59,

Addis, M., Pinna, G., Spada, S., Fiori, M., Sitzia, M.,Piredda, G., Molle, G., 2006a. The inclusion of a daisyrysanthemum coronarium) in dairy sheep diet. Part 1:milk and cheese fatty acid composition with particularto C18:2 cis-9, trans-11. Livest. Sci. 101, 5767.Addis, M., Pinna, G., Decandia, M., Sitzia, M., Piredda,A., Molle, G., 2006b. Effect of corn and beet pulp basedtes on sheep milk and cheese fatty acid composition whenerranean fresh forages with particular reference to conju-leic acid cis-9, trans-11. Anim. Feed Sci. Technol. 131,

04. Feeding of lactating ewes. In: Pulina, G. (Ed.), Dairytrition. CAB International, Wallingford, Oxon, UK, pp.

es, A., Mancuso, R., Vodret, B., Nudda, A., 1998. Effectenergy and protein concentration of milk urea nitrogenes. J. Dairy Sci. 81, 499508.

Nudda, A., Pulina, G., 2002. Nutritional strategies toactation persistency in dairy ewes. In: Proceedings ofreat Lakes Dairy Sheep Symposium, Ithaca, NY, USA,.abiddu, A., Bomboi, G., Ligios, S., Molle, G., 2003.

dietary non-fiber carbohydrates concentration on intake,igestibility and milk yield in Sarda ewes. In: Book ofof the 54th Annual Meeting of EAAP, p. 344.

Osan

m

Chameffin61

ChapmD.Imin

ColeminInIn

CortesthAn

DecanSuqufoRu

Decantatof

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groflan(A

DecanA.sitofTh

Delables

DentinEf(HofGr

Di Mi20agInGrp.

DouglR.co

ca

AgDove,

Ga, 2007. Comparison of grazing behaviour, dietary overlaprmance in non-lactating domestic ruminants grazing onheathland areas. Livest. Sci. 106, 271281..A., Orr, R.J., Penning, P.D., Rutter, S.M., 2004. Thepatial heterogeneity of two herbage species on the graz-iour of lactating sheep. Appl. Anim. Behav. Sci. 88,

F., Parsons, A.J., Cosgrove, G.P., Barker, D.J., Marotti,ning, K.J., Rutter, S.M., Hill, J., Thompson, A.N., 2007.f spatial patterns in pasture on animal grazing behaviour,d performance. Crop Sci. 47, 399415.

., Stuth, J.W., Holloway, J.W., 1995. Prediction ofnear-infrared spectroscopic analysis of fecal samples., F.N., Gill, D., Lusby, K., McCollum, T. (Eds.), Symp.eedlot Cattle, Oklahoma Exp. Sta. P-942, pp. 145155.

masceno, J.C., Jamot, J., Prache, S., 2006. Ewes increasee when offered a choice of herbage species at pasture.

i. 82, 183191., Molle, G., Ligios, S., Fois, N., Casu, S., Bomboi, G.,1996. Effets des differents niveaux de deplacement surarame`tres physiologiques et metaboliques et sur les per-

s des brebis Sardes en gestation. In: 3e`mes Renc. Rech.s 3, pp. 301304., Pinna, G., Cabiddu, A., Molle, G., 2005. Intake by lac-ts browsing on Mediterranean shrubland. In: Proceedingsh International Grassland Congress, p. 540 (Abstract)., Cannas, A., Cabiddu, A., Giovanetti, V., Fois, N., Sitzia,, G., 2007a. Effects of carbohydrate composition of con-n performance and nutrients utilisation efficiency ofes. In: De Vliegher, A., Carlier, L. (Eds.), Proceedings

h Symposium of EGF Permanent and Temporary Grass-t, Environment and Economy, Book of Abstracts, p. 35,., Giovanetti, V., Boe, F., Scanu, G., Cabiddu, A., Cannas,u, S., 2007b. Faecal NIRS to assess the chemical compo-the nutritive value of dairy sheep diet. In: Proceedings

h FAO-CIHEAM Meeting on Sheep and Goat Nutrition,iki, Greece, October1113, 2007, (accepted).

eyraud, J.L., Delagarde, R., 2003. Faut-il complementerlaitie`res au paturage? Prod. Anim. 16 (3), 183195.

T.P., Bessa, R.J.B., Belo, C.A.C., Ribeiro, J.M.R., 2006.preservation method on the nutritive value of sullamcoronarium), In: Lloveras, J. et al. (Eds.). Proceedings

eneral Meeting of the European Grassland Federation,Science in Europe, 11, pp. 252254.

., Stringi, L., Scarpello, C., Iudicello, P., Bonanno, A.,timing of daily grazing on annual ryegrass or sulla for-

ffects on milk yield and composition of Comisana Ewes.a, F.P. et al. (Eds.). Proceedings of the 20th InternationalCongress, Dublin, 26 June1 July 2005, Offered papers,

bstract).., Stienezen, M., Wagorn, G.C., Foote, A.G., Purchas,9. Effect of condensed tannins in birdsfoot trefoil (Lotustus) and sulla (Hedysarum coronarium) on body weight,t, and wool growth of lambs in New Zealand. N. Z. J.s. 42, 5564.ood, J.T., Simpson, R.J., Leury, B.J., Ciavarella, T.A.,

.L., Siever-Kelly, C., 1999. Spray-topping annual grass


pasture with glyphosate to delay loss of feeding value during sum-mer. III. Quantitative basis of the alkane-based procedures forestimating diet selection and herbage intake by grazing sheep. Aust.J. Agric. Res. 50, 475485.

Dumont, B.,vu par laelevage. F

DUrso, G., Afeeding onsemi-exte259272.

Fava, F., Boc2007. Monomiche eS.I.A., Ca

FAO, 2005. wFraser, M.D.,

Effects onand sequeLivest. Sc

Frutos, P., Ras2004. Is thtannin ext53, 1271

Garcia-Rodripasture ancompositiSociety oUK, Marc

Garcia-Rodritime spendairy sheeCongress,(Abstract)

Giovanetti, VMolle, G.ing behav(HedysaruQuality Lments, CO30Septem

Giovanetti, VNitrogen ewith diffe685 (Abst

Giovanetti, VG., 2007bconcentraMeeting oNutrition,

Glasser, T., Lalada, H.,methodolranean sh

Guerin, G., Gdes syste`m

Harvey, A., PDietary pclover at c242252.

Henning, P.Hsynchroni

characteristics and microbial growth. J. Anim. Sci. 71, 25162528.

Hoekstra, N.J., Schulte, R.P.O., Struik, P.C., Lantinga, E.A., 2007.Pathways to improving the N efficiency of grazing bovines. Eur. J.

gron. 26G.R., Vres againtinuumG.R., Mrmudeznsate fo93.idoost, Rtimingd forag, 1102e, R., R95. Nun, INRdy, J.,., 2003.grass i

ws. J. Du, S., Meding. Iture of30, 2001/Partu, S., Gmonito), 7680u, S.,ram, H

men deilk yiel, 1151u, S., Mbiddu,ctoriusediterras. 59, 2u, S., GminantsIRS) teu, S., G

ngar, E.nal moectrome.R.F., J

.K., Mam lamted wat1449.M.R.F.eodoro

vestigatevated cfect of sawed. A., Tollesecal near sheep.Meuret, M., Boissy, A., Petit, M., 2001. Le paturagenimal: mecanismes comportementaux et applications enourrages 166, 213228.vondo, M., Biondi, L., 1993. Effect of supplementarygrazing behaviour of Comisana ewes in a Mediterranean

nsive production system. Anim. Feed Sci. Technol. 42,

chi, S., Colombo, R., Musinu, S., Sitzia, M., Fois, N.,nitoraggio dei pascoli

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An update on the nutrition of dairy sheep grazing Mediterranean pastures