Reaching 90 percent of a heifer’s mature bodyweight by 22 months of age is a critical milestone.¹ Approximately two-thirds of New Zealand dairy heifers fall short of this target. This shortfall highlights the need for improved growth management. Seventeen percent² of milking heifers fail to return for a second lactation. Reproductive failure is the primarycause. This early culling is economically significant, as these heifers often do not produce enough milk in their first season to recover their rearing costs.
Importance of early nutrition
First crucial step of a calf’s life is receiving high quality colostrum, with 23 percent brix or higher, within six to nine hours of birth. Calves get the nutrition they need to start off right and receive passive immunity to combat viruses and bacteria. Follow this with a higher plane of nutrition from milk or Calf Milk Replacer (CMR) in the first five to six weeks of life to improve the calf’s growth rate.
This, combined with good rumen development and post-weaning nutrition, enables them to reach puberty sooner to reach the milking herd on time.
Accelerated milk feeding
In accelerated milk feeding programmes, calves are fed larger volumes of milk and total milk solids: 900 g to 1,200 g of milk solids a day. This converts to approximately eight litres of whole milk or six to eight litres of CMR mixed at 150 g / L. Accelerated feeding can support pre-weaning growth rates of 800 g or more per day with calves showing improved skeletal and muscle development. Faster growing calves require more protein, so if you are using CMR on your farm ensure it is a high quality CMR with crude protein levels of at least 26 to 28 percent.
Calves fed higher milk volumes early in life develop better mammary tissue, leading to increased milk production as adults³ which can be up to 39 to 78 kg MS more in their first lactation alone. With a $10 payout, the cost of feeding more milk to calves quickly pays off, while also benefiting calf welfare and immune function.
More milk means more milk
Calf meal is important for developing the rumen and preparing the calf for solid feeds. Early calf meal intakes are lower when more milk is fed. Before weaning, best practice is to take 10 to 14 days to reduce milk volumes and increase calf meal intake to ensure the rumen is developed enough to handle solid feed.
Continue feeding calf meal for four to six weeks post-weaning. Prioritising early life nutrition allows farmers to optimise calf growth, improve long-term productivity, reduce premature heifer losses, and have a more sustainable, profitable system.
¹ Liveweight targets | Dairy NZ: www.dairynz.co.nz/animal/heifers/lw-targets/
³ A.J. Molenaar, P.H. Maclean, M.L. Gilmour, I.G. Draganova, C.W. Symes, J.K. Margerison,C.D. McMahon, “Effect of whole-milk allowance on liveweight gain and growth of parenchyma and fat pads in the mammary glands of dairy heifers at weaning,” Journal of Dairy Science, Vol 103/Issue 6, June 2020, pages 5061-5069, ISSN 0022-0302 | https://www.sciencedirect.com/science/article/pii/S0022030220302216
