New UK research suggests the trend towards feeding calves very high volumes of milk replacer may not deliver sufficient returns for dairy farmers.
Feeding more than 1,050g of milk solids per calf daily can increase costs without producing meaningful improvements in growth or health, suggest two studies. Higher milk allowances may reduce starter feed intake and make weaning more difficult. The work was presented at the National Youngstock Conference in Birmingham.Dr Jessica Cooke, research and development manager at Feed For Growth (Volac Milk Replacers). Investment in calf rearing remained essential, said Dr Cooke. But feeding rates should also deliver value for money.
“Our research shows that higher milk volumes – of over 1,050g milk solids per calf per day – do not deliver significant improvements in growth or health, could be compromising performance at weaning and costing farmers more.”
Trial evidence
The studies compared moderate and high milk feeding programmes using both skim-based and whey protein concentrate-based calf milk replacers.
In both trials, calves offered more milk grew faster before weaning because they consumed more energy. However, they also ate less starter feed. That reduced their ability to cope with the transition from milk to solid feed. The first study involved 96 Holstein heifer calves at AFBI Hillsborough. Half received six litres of milk replacer each day, providing 900g of milk solids. The remainder received eight litres a day, supplying 1,350g of milk solids.
Dr Cooke said calves receiving the larger milk allowance frequently failed to finish their feeds. “There were higher refusals of CMR up to 28 days in the group fed eight litres. In fact, in the afternoon feed, the full volume of milk was not consumed 38 times.”
Starter feed intake reached 108kg per calf by day 90 in the six-litre group. It reached only 79kg in the eight-litre group. This meant the six-litre group were better equipped to cope with the weaning transition and were eating around 2kg of starter by day 63.
“The eight-litre group ate less starter. Consequently, although pre-weaning growth was higher in calves fed more, growth suffered at weaning,” said Dr Cooke.
Growth outcomes
Average daily liveweight gain to day 90 reached 0.93kg in the higher-fed group and 0.89kg in calves receiving six litres. The difference equated to only 3kg at 13 weeks. Health remained good in both groups.
“A growth rate of 0.89kg/day is excellent, and calves were more equipped to deal with weaning, so it’s worth questioning if the 26kg of extra CMR fed was worth the investment, particularly as a lot was wasted,” said Dr Cooke.
A second study at Duchy College in Cornwall reached similar conclusions. It compared 25 Holstein heifers fed either seven or nine litres of milk replacer daily through computerised feeders. Calves receiving the higher milk allowance achieved stronger growth before weaning. But lower starter intake led to a check in performance during weaning. Average daily liveweight gain to day 84 was identical at 0.78kg, and there was no difference in bodyweight by 12 weeks.
Practical advice
Dr Cooke said the results showed producers should focus on balanced nutrition rather than maximum milk volumes. Both studies showed that excessively high CMR volumes are not always necessary to achieve good growth, she said,
“Feeding more can make weaning more challenging. What’s important is farmers provide a CMR with good levels of protein, either from whey or skim, at a level which will promotes starter intakes which are just as important for rearing success as CMR.”
Dr Cooke recommended feeding around 900g-1,050g of milk solids per calf each day and weaning over at least three weeks. She also advised using milk replacers based on quality dairy proteins with 16-21% fat. This would encourage starter feed intake and support a smoother transition after weaning, said Dr Cooke.