Nutrition warning: Farmers advised to delay weaning

Beef farmers are being advised to consider delaying weaning over the winter months to make sure cows achieve optimal condition for spring calving.

Experts at SAC Consulting say that if cows are milking for longer, fit mothers will lose excess condition, which comes with the added benefit of reducing pneumonia risk for calves.

The advice follows a summer of exceptional grass growth, resulting in many cows carrying a condition score of 3 or more. As a result, autumn calving herds experienced severe calving difficulties and increased levels of forced Caesareans.

While energy levels of silage this year are very high – over 65 per cent of all silages have analysed at 11MJ of ME/kg dry matter – protein levels have not seen similar improvement, according to SAC. Many are still below 10 per cent CP in the dry matter.

Farmers may be looking to restrict silage intakes and make up the rest of the ration with straw, but nutritionist Mary Young said this will fail to meet protein requirements of the microbes in the cows’ rumen.

“As a result, they become less active and take much longer to break down forage so the rumen becomes impacted” she explains. “The silage and straw remain undigested so the cows can no longer eat.

“Adding a protein supplement, such as rapeseed meal, to the ration also supplies more energy so less silage can be fed, meaning that the cycle continues.

“It is therefore impossible to use these high-energy, low-protein silages for feeding dry spring calves and make them lose condition.”

Fortunately, she continues, the solution is simple. Delaying weaning means that more protein can be fed to meet the cows’ requirement, along with restricted energy, which forces the cow to milk off her back.

SAC is advising farmers to get silage analysed as soon as possible. If it has an ME value of 11 or more and protein content of 10 per cent CP or less, calves should not be weaned. Professional nutritional help in drawing up suitable rations is also advisable.