New research has highlighted the need to review calf milk feeding rates and question if a trend towards feeding excessive milk volumes is justified from both a performance and cost perspective.
Dr Jessica Cooke, R&D manager at Volac Milk Replacers, said it was fundamental to invest in calf rearing to produce healthy and productive replacements. However, cost benefit analysis needed to be carried out on feeding volumes.
“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,” she explained.
The two studies showed that higher feed volumes – either from quality whey protein concentrate or skim-based CMR – tended to deliver better pre-weaning growth due to increased energy supply, However, growth suffered at weaning as calf starter intakes were reduced. There were also high CMR refusals on calves fed high volumes.
AFBI Hillsborough study
Ninety-six Holstein heifers were enrolled in a study at AFBI Hillsborough. The CMR was Radiant Calf, a 23% crude protein, 18% fat, 30% skim-based product, enhanced with milk oligosaccharides.
Half received six litres (900g of milk solids) of CMR per calf per day across two feeds with milk reduced from day 43 to 63. The other half received eight litres (1,350g of milk solids) per calf per day, reducing from day 50 to 77.
Dr Cooke said: “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.”
Most notably, total starter feed intakes were higher (108kg per calf to day 90) in the group receiving six litres a day. This compared to 79kg in the group fed eight litres.
“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,” Dr Cooke explained.
Average daily live weight gains were 0.93kg/day to 90 days in the higher group and 0.89kg/day in the six-litre group. That translated into 3kg difference in weight at 13 weeks.
“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,” Dr Cooke said, adding that health was good in both groups.
South west study
Another study at Duchy College in Cornwall, compared performance of calves born in a September-October block and fed via computerised feeders.
The 25 Holstein heifers were fed Imunogard, a 23% crude protein, 21% fat, all dairy protein, whey protein concentrate-based CMR, including Celmanax yeast.
One group received seven litres (1,050g of milk solids) a day over 66 days, reducing over day 46-66, and the second received nine litres (1,350g of milk solids) per day over 80 days, reducing from day 58-80. Average DLWG to day 84 was identical at 0.78kg per calf per day.
“The calves fed the higher rate had stronger pre-weaning growth but checks at weaning due to reduced starter intakes meant average growth rates were the same for both groups and there was no difference in weight by 12 weeks,” Dr Cooke said.
“Both studies show excessively high CMR volumes are not always necessary to achieve good growth, and 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.”
To encourage starter consumption, Dr Cooke recommended:
- Offering around 900-1,050g of milk solids per calf per day and weaning over at least three-weeks;
- Feeding a CMR based on all dairy protein or a combination of dairy protein plus vegetable protein (hydrolysed wheat gluten), where the dairy protein is either good quality whey protein or skim (>30% skim inclusion); and
- Feeding a CMR with 16-21% fat, as higher fat can lower starter intakes.
