Sheep farmers could boost ewe immunity and improve lamb growth and performance by placing greater emphasis on quality protein feeding around lambing.
Around two to four weeks before lambing there is a natural lowering of immunity in adult ewes, which results in an increase in worm egg output for around six to eight weeks.
This peri parturient relaxation of immunity (PPRI), raises pasture contamination risk which can pose an infection challenge to young lambs, reducing their growth and performance at turnout.
Ewe nutrition has a significant impact on PPRI and particularly the supply of protein. However, a recent Mole Valley Farmers’ survey of 754 sheep producers, found that only 28% were aware that protein levels in their pregnant ewe feed could affect the worm output of ewes after lambing.
Mole Valley Farmers’ Nutritionist, Rebecca Moore said focusing on the level of Digestible Undegradable Protein (DUP) from four weeks pre-lambing to six weeks post-lambing can boost the ewe’s immunity and help combat PPRI.
Ms Moore said soya was a particularly good source of DUP, adding: “We’re potentially reducing wormer use and helping to achieve faster lamb growth rates by helping colostrum quality and quantity.
“DUP is particularly useful in the last three weeks of pregnancy when most of the lamb growth happens, which are both heavy on protein requirements. Plus, the udder is developing so you have a big demand on protein for that.”
Vet Andy Adler of Molecare Farm Vets said DUP will also help to improve lamb birth weights, which in turn will lower the likelihood of lamb losses.
He added: “If you can decrease worm eggs onto pasture in the spring, it supports lamb growth through the season. It also means you don’t need to use as much wormer, avoiding the build-up of resistance and preserving their use in the future.”
Mr Adler said it was also important to group ewes and feed according to body condition score and the number of lambs carried. However, results from the survey showed that only 42% of farmers had a targeted nutrition plan for their ewes, despite 62% going to the trouble of scanning.
“If you over-feed ewes you’ll have lambing issues and larger lambs are more likely to die due to lambing complications. On the other hand, thin ewes will produce smaller lambs and less colostrum which will compromise lamb growth and profitability,” he said.
He also stressed the importance of balancing diets according to forage stocks, adding: “Access to good quality forage is the biggest determinant of success. That’s why it’s so important to get forage tested. If forage quality is poor, you need to adjust the diet accordingly. You may even need to feed less concentrate.”