11 March 2023

Scanning of ewes and ensuring lambs receive adequate colostrum

Frank Campion, Animal & Grassland Research and Innovation Centre, Athenry, Co. Galway, reports on scanning of yearling ewes and the hill flocks, and we learn more about why making sure lambs receive adequate colostrum is so vital.

Scanning

The flocks lambing yearling ewes pregnancy scanned these in February and the results are presented in Table 2, with good results overall. These yearling ewes are currently being managed separately in the run-up to lambing. This will remain the case after lambing also, right up until weaning time.

All of the lowland flocks have been aiming to spread fertiliser once weather and ground conditions are suitable pre-lambing, with the target being 15-20 units of nitrogen per acre in the form of protected urea. Fertiliser usage will be monitored carefully throughout the year and the first application before lambing commences is an essential one for spring grass supplies.

The Teagasc BETTER hill sheep flocks pregnancy scanned their ewes during February, with the results from three of the flocks presented in Table 3. Pregnancy rates across the flocks are on target (>90%) this year, with litter sizes also within the targets for the three flocks presented. Some of the flocks with harsher hills and more restricted green ground are targeting a scanned litter size of 1.2 to maximise the amount of singles available to go to the hill early in the summer. Others with more green ground are happy to scan around 1.4, as there is more land available for twins after lambing.

Table 2: Pregnancy scanning results from yearling ewes on the BETTER farm sheep flocks.

Table 3: Pregnancy scanning results from the BETTER farm hill sheep flocks.

Colostrum

Making sure lambs receive adequate colostrum is vital. It serves three main functions.

1. Provides a dense source of energy and nutrients.
2. Source of maternally derived antibodies that provide the lambs with passive immunity.
3. Acts as a laxative to help clean the digestive

Lambs should receive 50ml per kg within the first six hours of life, increasing to 200ml per kg within the first 24 hours of life. A guideline amount for lambs is summarised in Table 1. The birth weights are a guide to what the average might be for singles, twins and triplets.

Where ewes have insufficient colostrum an alternative needs to be sought. Ideally this would be surplus from another freshly-lambed ewe or number of ewes. Cow colostrum is another alternative; however, it is recommended to mix it from a number of cows to avoid anaemia and it should be supplemented at a higher rate (30% more) than recommended sheep levels. There are a number of artificial colostrum products on the market; these should be used according to manufacturer’s instructions. Even when doing this, always try to ensure that each lamb receives some of its own mother’s colostrum to facilitate transfer of passive immunity.

Table 1: Colostrum feeding rates for newborn lambs.

These articles were first published in the Teagasc Sheep Newsletter – March 2023