More milk, healthier calves, stronger heifers

Increasing early milk intake for replacement calves is a proven way to support healthier, more content calves – and set them up for stronger performance later.

Feeding calves 20% or more of their birthweight in milk supports higher daily growth. For a crossbred calf averaging 32 kg at birth, this is about 6.4L per day. DairyNZ data shows around 25% of farmers feed less than this and could adjust their systems for better calf wellbeing and growth, while over a quarter of farmers feed 8L or more, supporting high growth rates.

In the first weeks of life, calves rely entirely on milk for energy, immune function, and activity. While meal and roughage help them get used to nibbling, they can’t absorb energy from solids until their rumen begins to develop. Restricted milk feeding can leave calves hungry, leading to more unrewarded feeder visits, cross-sucking and vocalisations, as well as less play. Offering more milk early supports growth, immunity and positive welfare, with calves showing more play behaviour and settling more readily after feeding.

Better early nutrition also boosts future productivity. A New Zealand study led by Bioeconomy Science Institute ruminant nutritionist Dr Ajmal Khan found that heifers fed 8L/day pre-weaning had more functional mammary tissue and less fat in the udder at seven months, compared with those fed 4L/day. Post-weaning growth was not compromised, and international studies show higher pre-weaning growth translates to increased first-lactation milk yield.

New Zealand farmers are well placed to lead in calf wellbeing. Group housing gives calves space to socialise and play, helping support positive welfare. To stay internationally competitive, however, calf-rearing practices need to keep pace with the latest science.

Updated DairyNZ calf-rearing resources will be available this winter, reflecting the latest research and offering independent guidance on housing, health, colostrum, feeding and weaning – making it easier to put science into practice to give your calves the best start possible.

Visit dairynz.co.nz/feeding-calves and keep an eye out for new resources this winter.