When it comes to making the decision of whether to feed calves whole milk or milk replacer, there is only one clear winner when it comes to nutritional value, according to US vet and calf specialist Sam Leadley.

“Whole milk is much better in terms of energy when compared to milk replacer. Milk is 35% fat, compared to 18-20% oil in replacer.”

The negatives of feeding whole milk are largely down to inadequate hygiene, he says. “One-third of farmers I visited in the UK would let milk sit in buckets in the parlour from morning until evening, creating a breeding ground for bacteria.”

The potential disease risk associated with feeding whole milk is also a major consideration, particularly considering the increasing problem with Johne’s incidence within the national herd. As such, feeding milk powder completely eliminates the risk of transmission.

Simon Marsh, from Harper Adams College, said when it comes to milk replacer, products should have a crude protein level of 20-23% and oil levels of 17-19%.

“It doesn’t pay to scrimp on replacer quality. If a calf is gaining below 400g/day from birth to weaning, they will not show compensatory growth later on.”

Key considerations when choosing between milk powder and whole milk:

• Feeding milk replacer eliminates the problems of Johne’s transmission via whole milk

• It’s important to weigh up the costs associated with feeding whole milk – even good quality replacer costs 18-19p/litre, compared to 25-30p/litre for whole milk – don’t divert valuable milk away from the tank unless you have to

• Trial work carried out at Teagasc Moorepark Research Centre found calves fed high-quality, whey-based calf milk replacer weighed more than 8kg more at eight weeks weaning and the cost of rearing was 49p/kg lwg less a calf over 10 weeks.