Spring is upon us, and paddocks around the country are filled with frolicking calves. A farm’s calf management can impact the future production potential of its herd.
Benefits of feeding calves more milk
Calves rely almost exclusively on milk for nutrition for the first six weeks as they progress onto solid feed (which drives rumen development). A recent Australian study1 found that regardless of whether a calf is receiving 4L or 8L of milk a day, their intake of dry matter (meal and hay) remains low over the first 10 weeks of life (below 1kg DM)/day).
Co-op Veterinary Programme Manager Mike Shallcrass says in the first five to six weeks, milk is key.
“More milk means bigger, stronger, healthier calves. The Australian study1 found that calves that were fed 8L of whole milk a day for 10 weeks were 19 kilograms heavier at weaning than those that were fed 4L a day. They also had higher immune and metabolic function,” he says.
“Feeding a calf more milk before it is weaned has a flow-on effect for future performance, improving fat yield, fat and protein-corrected milk, and first-service conception rates significantly (from 13% to 41%), and reducing the risk of culling,” Michael Shallcrass says.
Thrive rather than survive
The younger the calf is, the more it will convert feed into growth. Mike says farmers should prioritise milk in the early stages of life as feed conversion efficiency drops off with age.
In a 40kg calf, around 420g dry matter (DM) per day is used for maintenance. Feeding 4L of milk (or replacer) a day equates to around 600g DM/day, which leaves a calf with around 180g DM surplus, which will be used for growth. This surplus more than doubles if they’re fed 8L a day (1,200g DM/day), meaning more DM availability for growth (780g DM) since the maintenance requirements are already accounted for.
Keep them warm
Spring weather can be temperamental, and if calves are outdoors, their health can be compromised if it gets too cold. A 40kg calf in 0°C needs around 1.5L more milk per day than it does at 20°C.
“Being cold can have a significant impact on growth rates as calves burn more energy keeping warm. Adult cattle are resistant to temperature fluctuations, but for calves, concurrent cold days can have a cumulative negative effect on growth rates. Calves must be kept warm with shelter, deep bedding, or jackets, and given added nutrition. For every 10°C drop in temperature, add 100g of extra milk powder to achieve maintenance and growth,” Mike says.
Gradual weaning
Ideally, calves should be weaned over two to three weeks, so they transition smoothly between milk and solid food (meal and pasture). Monitor solid feed consumption pre-weaning to ensure calves are eating enough grass and meal. Measure growth, health and behaviour and weigh the calves to check growth rates. The more solid intake a calf has before weaning, the less likely they are to have a drop-off in growth rates post-weaning.
“There are a lot of ways farmers decide when to wean off milk to solid feed and from meal to pasture: age, milk intake, body weight, forage intake, and meal palatability. There is no one-size-fits-all answer. We recommend measuring feed intake, growth, health, rumination and behaviour to come up with an approach that works for your farm system. Having hard feed and water available from an early age makes the weaning process easier,” Mike says.
For further information, products or advice, your local Farm Source team is on hand to provide any support you need with calf rearing.
