May 2019

Pasture based pig systems

Forage in a pig’s dietAccounting for around 60% of total production costs, feed can have a substantial impact on herd and financial performance. On some farms, forage-based systems can provide economic and animal welfare benefits.

As pigs are not ruminants, they cannot be sustained on an all forage diet. However, forage can still contribute a valuable part of their energy, protein and mineral requirements and provide added enrichment.

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Sows

• A lactating sow requires around 80MJ of energy a day from her diet;

• In a grazing situation she may consume 2kgDM a day of forage – supplying nearly a third of the energy demand;

• To achieve this the forage must be high quality and accessible; • Grazing trials using dry sows on restricted concentrate diets recorded forage intake of 2kgDM/day which is around 50% of their dietary requirement.

Growing pigs

• Growing pigs’ nutritional demands are less likely to be met by a predominantly foraged based diet. They require a higher concentration of nutrients during this stage of development;

• Grazing studies have found that outdoor growing pigs offered ad lib concentrates will consume around 4% of their diet from forage;

• Energy demands of a foraging pig are higher, meaning growth rates may be compromised unless diets are supplemented accordingly. Take this into account and adjust live weight gain targets accordingly;

• Growing pigs can be fed conserved forages such as silage – especially if short chopped. Feeding trials with ad lib silage supply saw around 1kgDM silage in the diet of growing pigs. Although silage wastage was around 25%.

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• Enrichment and behavioural benefits;

• Diet variation;

• Source of vitamins and minerals;

• Silage may be a more viable crop to grow on-farm rather than growing arable crops for pig feed;

• Cost savings;

• Support gut health;

• Potential market premium dependant on production system and market.

Tips on how to assess your soil

• Test the pH of your soil. Maintaining soil pH between 6 and 6.5 is crucial to soil health and ensuring the availability of nutrients to the growing plants. Low pH soils will be more prone to weed ingress and less likely to recover quickly from poaching and trafficking damage;

• Dig a hole! Check the soil profile, texture and structure of the top 30cm and also of the subsoil below;

• Soil type can change from field to field or even within fields so check the soil in a number of locations;

• A healthy, fertile and well manged soil is one that shows high levels of biological activity (i.e. soil organisms such as earthworms will be present), is well structured and free draining. Keep an eye out for compacted and poorly drained soil as it will be prone to erosion and potential nutrient losses.

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Forage options There are several options that could be considered for establishing pasture suitable for pig grazing.

1) Late summer establishment of multispecies ley which could include ryegrass, timothy, meadow fescue, chicory, plantain, red and white clover plus herbs. Grazing by sheep in autumn would increase the sward density ready for the introduction of pigs in the spring;

2) Spring establishment of Italian ryegrass/westerwold offers a less expensive option to a multispecies ley but there may be a loss of forage quality in the summer;

3) As part of an arable rotation after cereals a cover crop such as mustard or radish could be established in autumn to provide pig grazing in early spring before moving them onto grass;

4) Stubble turnips sown in late spring or summer for grazing through summer/autumn can be useful to fill any summer drought forage gap;

5) Rape, with or without grass, or spring oats sown in spring can provide a restricted grazing period for a few months and act as a pioneer crop ahead of establishing a long-term grass ley. Annual legumes such as crimson clover can also be included to build fertility and provide flowers for pollinating insects.

• Sward heights between 7cm – 20cm are recommended. Swards below 7cm can limit animal intake and above 20cm will tend to be of lower quality with more stem and dead material. As such wastage will be greater;

• To provide high quality swards the soil pH should be between 6-6.5 and PK indexes of 2;

• Any soil structural issues need to be addressed before the sward is established;

• Suitable pasture may not be available during the entire year. As such feeding programmes may have to be modified from one season to the next.

Clover Herbal Ley

RadishItalian rye grass and plantain

Forage quality and animal intakesEnergy and protein levels will be greatest with ryegrass and clover dominant swards although they can also include species such as chicory and plantain to boost protein levels and summer production.

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Pigs will root and damage pasture meaning that most grazing swards will be short term, although rotational grazing can allow subsequent grazing through the season.

Field selection and managementAs soil damage is inevitable care should be taken to avoid any potential soil erosion and run-off. Select fields for grazing that are low risk i.e. sighted away from water courses with no severe slopes and that are freely drained.

• Earthworms can contribute significantly to the diet of pigs so healthy soils with the correct pH and high in organic matter can boost animal performance;

• Moving shelters, feeding areas and water troughs can help to reduce localised soil damage;

• Introducing a fresh strip of grazing tends to result in more soil damage than introducing a larger fresh block less frequently;

• High stocking rates will increase the potential for soil damage. Rates of around 5 sows/ acre should limit damage and allow scope for rotation to fresh pasture through the season.

• Avoid pig grazing in any field that already has a high phosphate status (Index 3 and above) to avoid risks of phosphate loss and further build-up of soil P reserves;

• Consider buffer strips to protect any ditches and reduce run-off risks;

• Avoid machinery traffic if possible – low stocking rates should mean that all feed can be brought in by hand rather than vehicle;

• Have contingency plans to relocate pigs if weather and soil conditions deteriorate.

© Menter Moch Cymru 2019. No part of this publication may be reproduced without the prior permission in writing of Menter Moch Cymru, other than by reproduction in an unmodified form for the sole purpose of use as an information resource when Menter Moch Cymru is clearly acknowledged as the source, or in accordance with the provisions of the Copyright, Designs and Patents Act 1988. All rights reserved. While Menter Moch Cymru seeks to ensure that the information contained within this document is accurate at the time of printing, no warranty is given in respect thereof and, to the maximum extent permitted by law, Menter Moch Cymru accepts no liability for loss, damage or injury howsoever caused (including that caused by negligence) or suffered directly or indirectly in relation to information and opinions contained in or omitted from this document.