Beef farmers should consider delaying weaning over the winter months to ensure cows achieve optimal condition for spring calving after a summer of exceptional grass growth.

According to Mary Young, nutritionist at SAC Consulting, beef cows across the country are generally in very good condition, and by ensuring they milk their calves for longer will help them lose the excess condition. Delaying weaning also has the added benefit of reducing the risk of pneumonia in calves.

The advice comes after excellent summer of grass growth led to many cows carrying a condition score of 3 or above. This, in turn, resulted in severe calving difficulties and increased levels of forced caesareans in autumn-calving herds.

Farmers may be looking to restrict silage intakes and make up the rest of the ration with straw. But although energy levels of silage this year are extremely high – more than 65% of all silages have analysed at 11MJ of ME/kg dry matter – protein levels have not shown a similar improvement, with many still below 10% CP in the dry matter.

“Restricting the intake of these silages and topping them up with straw will fail to meet the protein requirements of the microbes in the cows’ rumen," said Ms Young.

"As a result, they become less active and take much longer to break down forage so the rumen becomes impacted. The silage and straw remains 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 the solution is simple – weaning should be delayed. Leaving calves on their mothers means that cows keep lactating so more protein can be fed to meet the cows’ requirement along with restricted energy, forcing the cow to milk off her back.”

Farmers are advised to get their silage analysed as soon as possible. If it has an ME value of 11 or more and protein content of 10% CP or less, then calves should not be weaned. They should also get professional nutritional help in drawing up suitable rations.