Lamb mortality is a major cost to Irish sheep farmers with each 1% change in lamb mortality nationally costing €2.5m annually. This stark figure was highlighted by Tim Keady, Teagasc, at the recent Teagasc lowland sheep conferences.

Tim added that the greatest percentage of lamb mortality occurs within 24 hours of birth with the two main causes outlined as dystocia (hard lambing) and infection. Both of these are potentially preventable and improvement in these areas has the scope to greatly improve the profitability of sheep enterprises.

The presentation delivered was focused on improving ewe productivity through lessons learned from the EU SheepNet project. When it comes to reducing lamb mortality, the main issues identified by farmers in Ireland and across the participating project partners, namely France, Italy, Romania, Spain and the UK, along with Turkey, are detailed in Table 1.

The rankings of issues varied slightly but it is clear that having preparations put in place for lambing well in advance is one of the main areas where improvements can be made.

The main animal issues highlighted as having the potential to reduce lamb mortality are listed in Table 2 with full agreement between all stakeholders that colostrum, lamb vigour at birth and lamb birth weight/dystocia are the most important factors.

Colostrum is covered in depth on page 58, while lamb vigour at birth and lamb weight is directly influenced by the late pregnancy feeding programme. Ewe and ram genotype also has a role to play.

Targeted feeding

Tim says that one of the most significant factors underpinning a successful lambing is feeding according to litter size and predicted lambing date.

This is because there is a major increase in the energy requirement of ewes in late pregnancy, rising by 40% in single-bearing ewes, 60% in twin-bearing ewes and 70% in triplet-bearing ewes in the final six weeks of pregnancy.

Targeting concentrate supplementation to ewes carrying multiple litters will address many of the issues outlined in Table 1 and Table 2.

Lamb liveweight has a particularly strong correlation with lamb mortality, as detailed in Figure 1.

The optimum birthweight outlined by Tim is 6kg for singles, 5.6kg for twins and 4.7kg for triplet lambs.

The majority of mortality with single-born lambs is linked with large lambs weighing greater than 7kg, while mortality with triplets and quadruplets is identified as stemming from a combination of lighter weaker lambs standing a lower chance of survival and issues with delivery.

Highlighting the effect of litter size on mortality, Tim says that approximately 6%, 7% and 21% of lambs born as singles, twins and triplets die. Along with reducing mortality, achieving optimum liveweight reduces labour requirements.

In terms of concentrates, there is a much greater awareness among farmers as to the importance of selecting feeds with high-energy ingredients.

Maize meal is likely to be the primary ingredient in many formulations this winter

According to Tim, the main ingredients in a late-pregnancy concentrate should comprise soya bean meal, maize meal and barley followed by rapeseed, soya hulls, beet pulp, maize distillers and maize gluten.

Maize meal is likely to be the primary ingredient in many formulations this winter, a fact Tim says it is not surprising given it has a superior feeding value and is costing €30/t to €40/t less than barley. The recommended crude protein content is at least 19% with soya bean meal the main protein source.

The concentrate formulation used for this season’s lambing in Teagasc Athenry is as follows: 28.5% maize, 18% soya bean meal, 15% soya hulls, 8% barley, 8% rapeseed, 5% distillers, 5% maize gluten, 5% beet pulp, 5% molasses and 2.5% minerals and vitamin E.

Reducing infection

The environment in which lambs are born into has a massive influence on their health and well-being.

There are two immediate avenues for bacteria to gain entry – through the navel and ingested. Therefore, it is critical that the environment into which lambs are born is clean.

Tim highlighted results of a survey, which showed that 23% of farmers do not clean or disinfect lambing pens once lambing commences

Again, advance preparations in this regard are important with an inadequate environment increasing the risk of the udder, teats and wool on the underside of animals being dirty and increasing the risk of bacteria being ingested when the lamb first tries to suckle.

Maintaining a hygienic environment and taking steps to reduce bacterial buildup in the environment is also important with the risk increasing as lambing progresses.

Tim highlighted results of a survey, which showed that 23% of farmers do not clean or disinfect lambing pens once lambing commences.

Cleaning individual lambing pens and disinfecting via spreading lime was recommended after each ewe and lamb passes through while where no cleaning is done and labour availability is tight then any change that brings about more regularly cleaning will deliver benefits.

In terms of the number of lambing pens available, the recommendation is one lambing pen to every seven to eight ewes with this rising to one pen to every five to six ewes in high-prolificacy flocks.

Lime can also be used to good effect in group lambing pens by spreading on bedding before topping up straw or spreading in high-risk areas such as along the feeding passage or around drinkers.