Calf growth rates must be maximised

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Many Irish dairy farmers are not maximising the growth rates that can be achieved by their calves, according to Tipperary-based veterinarian Martin Kavanagh.

“Cattle are most efficient, when it comes to converting feed into daily liveweight gain, during the first two months of life,” he said.

“So it makes sense that farmers should strive to maximise this potential. But the reality is that many are not achieving this level of calf performance. And this is a reflection of the feeding strategies they implement.”

Speaking at a recent Cargill-hosted seminar for nutritionists in Armagh, Kavanagh said that farmers must “re-calibrate their thinking’ when it comes to feeding calves milk.

“Volume is really irrelevant in this context,” he said.

“The key determinant is the amount of milk solids offered to the calf.”

Kavanagh said that 350g of milk solids represents a daily maintenance requirement for a 40kg calf.

“And it will require double this amount to ensure that the calf is achieving an optimal level of growth. It is feasible to have calves achieving well in excess of 500g of daily liveweight gain pre weaning.

“This level of feeding equates approximately to a standard milk volume of 6L per day, based on cow’s milk containing 125g of solids per litre.”

He confirmed the absolute necessity of getting 3L of colostrum into the newborn calf within two hours of first milking.

“But colostrum quality reduces by a factor of up to 4% for every hour that passes after the calf is born. So it makes sense to have the cow milked as quickly after calving as possible.

“I know that it can be a bind to take a cow from a calving box up to the milking parlour in the middle of the night.

“But most cows will stand quietly for at last an hour after calving, due to the high levels of the hormone oxytocin 
that are circulating in her system.

“This should make hand milking the cow a realistic option.”