Abortions in Sheep

What causes them and what can we do about it?

Dr. Jocelyn JansenDisease Prevention Veterinarian – Small Ruminants

Veterinary Science & Policy, OMAF

Grey Bruce Farmer’s Week – Sheep Day, January 11, 2014

Sheep Abortions

• The Issue:– industry expansion has led to

poor biosecurity implementation• buying animals from multiple sources• both new & veteran producers

– increased incidence of flock abortions and/or abortion storms

Buyer Beware• Sources of replacement animals

– salesbarn• animals mixed together from multiple farms

– leads to multiple problems

• good chance that animals are someone else's culls• if the price is too good to be true, don’t buy

– private sales• animals from 1 source minimizes disease risk• discuss flock history & look at management

– management should be the same or better than yours

– home grown replacements• maintain a closed flock

Working with a Veterinarian

• Benefits of a vet-client-patient relationship– help you develop a flock specific health program

focus is on prevention !!• establish goals for the flock• keep good records that can be reviewed

– know when to call the vet versus waiting and seeing

• perform post-mortems and diagnostics• source of vaccines and antibiotics and

the knowledge of how best to use them

How Many Abortions Are Too Much?• In most flocks the visible abortion rate is

<2%

• The accepted rate of abortion is <5%– concern if >5%– concern if clustering of abortions in time/group– chronic abortion rates of 2 – 5% yearly suggest

an endemic problem

INVESTIGATE

Record Keeping

Abortion Rate

= number of ewes aborting

number of ewes pregnant or exposed to ram

Lamb Mortality Rate (1st 7 days)

= number of lambs born alive but dying in 1st 7 days

number of lambs born alive

Causes of Abortion• Infectious Causes

– Coxiella burnetii (Q Fever)– Chlamydia abortus– Campylobacter– Toxoplasma– Listeriosis– Salmonella– Border disease– Leptospirosis– Cache Valley

• Non-infectious Causes– Iodine deficiency– Stress & trauma– Selenium deficiency– Starvation

• energy/protein deficiency

– Overnourishment• ewe lambs

– Toxic plants

Warning:

all 4 are ZOONOTIC !!

CCCT – Zoonotic Risks• Coxiella (Q fever)

– flu-like symptoms, repeated fevers, pneumonia, heart & liver problems (inhalation, raw milk, indirect contact)

• very few bacteria are required to cause infection in a human

• Chlamydia– miscarriages / stillbirth in pregnant women (ingestion)

• Campylobacter– vomiting, diarrhea, fever with C. jejuni (ingestion)

• Toxoplasma– birth defects in human fetuses, inflammation of the brain

in immunocompromised adults (undercooked meat, cleaning litter box, raw milk)

What do we See in Ontario? AHL Project (Hazlett et al, 2013)Final Diagnosis Sheep (cases,%)

n=163

Goats (cases,%)

n=96

Toxoplasma gondii 31 (19%) 16 (17%)

Coxiella burnetii 12 (7%) 15 (16%)

Chlamydia abortus 19 (12%) 36 (37%)

Campylobacter spp 21 (13%) 0

Salmonella spp 3 (2%) 0

Listeria monocytogenes 1 (1%) 1 (1%)

Other infectious bacteria 7 (4%) 5 (5%)

Unknown cause 73 (45%) 30 (31%)

• Coxiella was detected in 69% (113/163) of sheep abortions and 75% (72/96) of goat abortions– cause of abortion in 7% (s) and 16% (g)

• Chlamydia was detected in 26% (42/163) of sheep abortions and 56% (54/96) of goat abortions– cause of abortion in 12% (s) and 37% (g)

AHL Project

COMMON

Q Fever in Ontario

• “Prevalence of Q fever (Coxiella burnetii) in Ontario sheep flocks and goat herds and their farm workers”– collaborative effort – OVC, OMAFRA,

MOHLTC, PHO • 148 farms randomly selected (meat/dairy)

– 35 animals per farm randomly selected– at least one lambing/kidding – blood test (antibodies)

• farm management survey

Q Fever in Ontario -- Results• Meat sheep

– farm-level: 42% positive flocks (21/50) • flock with at least one animal testing positive

– animal-level: 10% positive sheep (166/1619)

• Dairy sheep– farm-level: 64% positive flocks (14/22) – animal-level: 24% positive sheep (181/744)

• Within-herd prevalence ranged from 0% - 74% for sheep farms

Q Fever in Ontario – Human Results

• Farm workers tested if they wanted– 1-3 people/farm, >14 years of age– blood test (antibodies)– results for sheep and goat farm

workers not separated– 79% of farms (59/75) had at least 1

person with antibodies to Coxiella– 67% of farm workers (116/172) had

evidence of past infection/exposure

What You Might See in Your Animals

• Return open– losses in early to mid gestation are often

undetected• animals are rebred

• Mummified fetuses– not common

• Abortion– most commonly seen during last 2 months

• Stillbirths • Weak lambs

– often don’t survive past first week

Ewes rarely become ill

Diagnosing the Cause of Abortions

• Testing– very important to submit both the fetus AND

placenta to a diagnostic lab• submit more than one fetus/placenta if possible• as clean as possible & not frozen (keep chilled)• cause of abortion can vary from year to year

– blood samples taken from ewes not as useful• exposed versus cause of abortion• spend your money on placenta/fetal samples

Diagnosing the Cause of Abortions

Management of the Aborting Flock – Things to Consider• Separate females still to lamb from those that have aborted– move to a clean area

• keep aborted ewes in the contaminated pen or pasture

– deal with females still to lamb first• prior to aborted females and new moms

• Remove bedding & fetal materials (bury, compost) decrease environmental load– wear masks to prevent inhalation of organisms– don’t spread manure when windy

Management of the Aborting Flock – Things to Consider• Remember the ZOONOTIC risks

– wear gloves for all lambings• wash hands frequently

– wear coveralls and boots• change and clean frequently during lambing• don’t wear the same ones to manage the rest of the

flock

– pregnant women should not assist at lambing• in addition to aborted, newly lambed

– children & elderly also at risk– drinking raw milk is a risk factor

Coxiella burnetii (Q fever)

• Common cause of abortion in sheep & goats– organism can survive in dust for years

• Sources of the organism– aborted fetus, placenta, uterine fluids

• cattle, cats, rodents, birds & insects can also be a source of the organism

– vaginal discharge, milk, manure, urine– venereal spread by males – “carrier females”

• immunity is not complete large proportion of flock may be shedding with few abortions

• shed organism but deliver normal lambs

Coxiella burnetii• Infected by inhaling contaminated air/dust or

mucous membrane contact with aborted materials or birthing fluids– localizes in placenta

• abortions, stillbirths and/or weak lambs

• Treatment– antibiotics?

• may or may not stop further abortions• carrier females will still shed the organism• effectiveness of feed vs injections• drug residues in dairy animals

TALK TO YOUR VET

Menzies

Coxiella burnetii• Prevention

– separate pregnant ewes from aborting flock• management of environment & contaminated materials

• don’t spread manure when windy

– good management avoid overcrowding, good nutrition

– biosecurity “buyer beware”– Coxevac® vaccine

• veterinary application to CFIA

• decreases number of abortions

• decreases shedding into the environment

• vaccinate unexposed replacements twice before breeding, booster yearly

TALK TO YOUR VET

Chlamydia abortus• Common cause of abortion in sheep & goats

• Sources of the organism– aborted fetus, placenta, uterine fluids

• after aborting, immunity lasts about 3 years• birds and insects may play a role in spreading disease

– “carrier females”• vaginal secretions at time of heat

– rams can be temporarily infected• venereal spread

– infected through mucous membranes or eating contaminated materials or feeds

Chlamydia abortus• Incubation period = 50 to 90 days• Individual Scenario

– infected in early to mid gestation• abortion• stillbirths and/or weak lambs

– infected in late gestation or when not pregnant• abort during next pregnancy

• Naive Flock Scenario– 1st year replacements abort– 2nd year abortion storm– 3rd year ewe lambs abort

Chlamydia abortus

• Treatment– antibiotics?

• during an outbreak– multiple injections– effectiveness of feed vs injections– often poor results due to long incubation period

& damage done to placenta– drug residues in dairy animals

Fos

ter,

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TALK TO YOUR VET

Chlamydia abortus• Prevention

– separate pregnant ewes from aborting flock

• manage ewe lambs separately• management of environment & contaminated materials

– vaccinate (Chlamydia psittaci Bacterin)• twice before breeding & booster yearly• vaccine does not prevent shedding but will decrease

abortions• NOTE cat vaccine does not work (different strain)

– good management avoid overcrowding– biosecurity “buyer beware”

TALK TO YOUR VET

Campylobacter

• Common cause of abortion in sheep

• Campylobacter jejuni– sporadic abortions

• more so in Ontario

• Campylobacter fetus subspecies fetus– large abortion storms

• more so in western flocks

• Incubation period = 7 to 60 days

Campylobacter• Sources of the organism

– “carrier sheep” have the organism in their intestines

• environmental contamination via manure

– aborted fetus, placenta, uterine fluids from aborted females

– birds (crows) can spread organism between flocks

– others infected by eating contaminated materials or feeds

Campylobacter• Most abortions occur during the 3rd

trimester– lesions seen on placenta & in fetus – ewes are not ill

• some become immune (at least 3 years)• while others become carriers

– if infected 2 weeks before lambing may see stillbirths and weak lambs

Campylobacter• Treatment & Prevention

– antibiotics• stop the outbreak• effectiveness of feed vs injections

– separate pregnant ewes from aborting flock• management of environment & contaminated materials

– vaccinate (Campylobacter fetus-jejuni Bacterin-Ovine)• twice before breeding & booster yearly• effectiveness questioned due to strain differences?

– good management avoid overcrowding– biosecurity “buyer beware”

TALK TO YOUR VET

Toxoplasma• Common cause of abortion in

sheep & goats– parasite infection

• cat rodent lifecycle

• Source of the organism– nonimmune kittens are infected by eating rodents

• shed large numbers of toxo eggs in their manure• kittens defecate & bury manure in hay & feeds

– adult cats are immune, don’t shed eggs

– sheep infected by eating contaminated feed and/or water

Toxoplasma• Individual Scenario

– if ewe not pregnant but exposed to eggs• become immune and do not abort

– if infected before 40 days post breeding• return open

– if infected between 40 and 120 days• mummified fetuses, abortion

– if infected after 120 days• stillbirths, weak and/or normal immune lambs• normal & affected can be delivered at one time

Toxoplasma• Immunity

– life-long for sheep

• No treatment for current abortions• Prevention

– keep cat feces out of feed & water• provide litter box, don’t feed top bales, feed bins • stray cat & pasture control difficult

– neuter kittens and control rodents• exposing youngstock to kittens works poorly

– coccidiostat fed throughout gestation• no evidence that it treats existing infections

Conclusions• Abortions are costly to your bottom line• Visible abortion rate <5%• Investigate submit placenta (and fetus)• CCCT most common causes

– ZOONOTIC!!

• Separate pregnant females from aborting flock

• Use of vaccines and antibiotics• Biosecurity “Buyer Beware”, clean

coveralls, gloves, hand washing, masks, etc

Questions ?