Optimising Ewe Performance
Increasing the number and weight of lambs weaned next season means prioritising your ewe flock management before tupping. The average Body Condition Score (BCS) of the ewe flock can slip during dry summer periods, with tail end ewes most affected.
The maintenance cost of feeding an ewe is constant with late pregnancy and lactation demands requiring feeding at levels two to three times maintenance. On many farms though, the opportunity is overlooked, and production is lost from those ewes with low BCS at tupping.
Ewes, at least BCS 3 at tupping, wean heavier lambs at the end of the year than ewes at BCS 2. Not only is the ewe’s own survival improved with lower death rates, but it is also less likely to be culled. Lamb birthweights will be higher with greater brown fat content to help them survive inclement weather at lambing.
However, having ewes at BCS 4 or greater, does not equal higher production. It is worth managing these well-conditioned ewes separately, as they have the tendency to get even fatter due to their dominance in the mob. In late pregnancy, they have a higher risk of metabolic disease and increased death rates.
A BCS 2 ewe is eight to 10 kg lighter than a BCS 3. Putting your hands on your ewes is the only way to identify those with low BCS. Visual assessment can miss ewes that could benefit from gaining half a BCS or about four kg.
Low BCS ewes need to gain weight before tupping, so preferential feeding is the most important factor. For every increase in BCS at mating, up to BCS 3, you will see a corresponding increase of six to 10 percent in lambing.
Changes in BCS in the three weeks leading up to, and during mating, are the key drivers of ovulation and conception rates in ewes. If feed conditions are tight, before and during mating, then strategic feeding of light BCS ewes (<3) through a higher pasture intake, grain/sheep nuts or conserved crops is most effective. While highly fecund flocks can achieve good scanning percentages at lower body condition scores, this does not always result in more lambs weaned.
In most cases, low conditioned ewes will respond to preferential feeding alone during summer and are not necessarily more impacted by worms than others. A faecal egg count and larval culture gives you a good indication of the severity of any worm burden. Underweight ewes can indicate other underlying diseases like facial eczema damaged livers, pneumonia, or missing teeth.
These ewes need to be culled prior to mating as they are likely to be dry or have high death rates during winter. Conditioned ewes are easier to manage and do not require costly additional feeding. You will be rewarded by constant management of the mob throughout late summer and early autumn with the more kilograms of lamb weaned per ewe.
For assistance in optimising ewe performance, contact your PGG Wrightson Technical Field Representative today.
