Feeding the in-lamb ewe

When planning a feeding strategy for ewes in late pregnancy it is important to know the quality of the forage. The Hillsborough Feeding Information System (HFIS) provides sheep farmers with a prediction of grass silage quality, and provides guidance on the level of concentrate required to supplement the silage in late pregnancy. For sampling packs and pre-paid postage bags please contact phone (028) 9268 583 or e-mail:info@afbini.gov.uk

The effects of grass silage quality on concentrate inputs are also shown in Table 1. Baled silage can provide a practical feeding option, when well-preserved and suitably stored. However, unchopped big bale silage will have lower intake characteristics than precision chopped silage and will thus require extra supplementation. Also be wary of poorly fermented silages, especially big bales as due to the higher silage ph, there is the potential for listeriosis in sheep if soil, faeces or rotten vegetation is present.

Table 1. Concentrate feed level required for twin-bearing ewes (KG/ewe/day)

^†  (ME 11.7 MJ/KG DM ; CP 14.6% DM)

^‡  (ME 9.6 MJ/KG DM ; CP 10.5% DM)

If more than 400g of concentrates are to be offered daily, the feed should be equally split into two feeds. The timing of feeding should be consistent to maintain rumen function, which is thought to reduce the risk of prolapse.

An alternative to increasing the concentrate allowance in a step-wise pattern is to feed at a flat rate.  For example, the excellent quality silage from the unchopped big bale  in Table 1 could be supplemented with 300g concentrate/ day for the last 6 weeks of pregnancy. This means there is initially an over-supply of nutrients, but this compensates for an under-supply during the last few weeks.

Concentrates should have an energy content of at least 12.5 MJ/KG dry matter (DM) and a protein content of at least 16-18% on a fresh basis.  Examples of suitable rations for pregnant ewes include:

Information from the industry would suggest that where a flock has a history of prolapse, energy should be supplied in the form of fibre such as sugar beet pulp, rather than as starch from cereals, as in ration 3. It is also important to discuss vitamin and mineral requirements with your local veterinary practitioner. The benefits to sheep and lamb health from Selenium and Vitamin E supplementation have been well documented on farms where deficiencies are present and the target should be to ensure the ewe gets 100mg Vitamin E/day prior to lambing.

Ewes offered all-grain diets perform equally as well as those offered grass silage-based diets.  All grain diets should include a high proportion (around 30%) of fibrous by-products, such as sugar-beet pulp or soya hulls, to avoid acidosis and should supply no more than 14% crude protein. Small amounts of straw (0.1 KG/d) are needed to maintain a healthy rumen.

Table 2. Concentrate requirements of a crossbred ewe offered straw (KG/day)

Silage analysis key to planning ewe supplementation