Calving is a busy time for farmers, but the quality of care your calves receive early on has a big impact on how quickly you can wean them and how well they perform when they enter the milking herd.
Establish drinking behaviours
Co-op Veterinary Programme Manager Mike Shallcrass says that a low milk feeding rate for calves is a false economy and delays weaning age, while high feeding rates will grow bigger calves faster, letting you get them outside sooner.
The rumen of a cow is full of microbes that break down plant fibres and extract nutrients from feed that would otherwise be indigestible. However, calves are born with an undeveloped rumen and can’t digest solid food. For the first few weeks, while the rumen is developing, calves rely entirely on milk to stay alive and grow.
“The more milk you can give them, particularly in the first four weeks of life when their rumen isn’t developed yet, the better they’re going to grow. Growth in the first two to three months is mainly driven by milk feeding,” Mike says.
Colostrum
Ensuring your calf drinks enough high-quality colostrum within 24 hours of birth is critical to ensure it gets the most immunity and antibody benefits. Colostrum provides essential molecules that prime the calf’s immune system to protect it against disease, and growth promoters that are important for the development of the calves. After 24 hours, these molecules are less able to be absorbed through the lining of the calf’s gut and prime the immune system, but can still provide local protection against bugs in the gut.
Ideally, a calf should have at least 4 litres of colostrum in its first 10 hours of life. Farmers should keep a watchful eye on calves with their mothers. If they are not feeding in the paddock, they might need some help, either supplemented with colostrum but still left with their mum, or taken to housing and given colostrum by teat or stomach tube. Weather conditions can have a big impact on calf vitality, and you may need to intervene more often when it’s cold and wet.
Use the best quality milk
Transition milk (from milkings two to six) provides higher milk solids than whole milk and also antibodies (though not to the same degree as colostrum).
Calf milk replacer
For young calves, their diet should be as close to whole milk as possible. There are many different types of calf milk replacer (CMR) on the market, with subtle differences that can make comparisons difficult, so it’s important to understand what to look for in a CMR. Most of the differences relate to the types and concentrations of fat and protein in the product.
Protein: Whole cow’s milk has 3.3-3.5% protein, mainly casein (~80%) and whey (~20%). CMR’s should replicate this. Casein-based CMRs, like Ancalf™ form curds in the calf’s stomach, aiding digestion and nutrient absorption, while whey-based CMR’s move quickly to the small intestine, which may be challenging for very young calves.
Fat: For calves under four weeks, ensure the CMRs fat content primarily comes from milk fat, limiting vegetable fats to 10%. Whole Milk Powder (WMP)-based CMR’s, like Ancalf™, provide milk fat, crucial for rumen development due to its unique fatty acid profile, including butyrate.
How much should you be feeding?
Scientific studies have found that calves that are fed 700 grams to 1kg of milk solids per day across two feedings tend to have the highest growth rates. Increasing the milk allowance should be considered an investment rather than an expense. One way to ensure young calves get enough milk allowance is to use a divided calf feeder for the first few days of life.
“Make sure any feeder you use is cleaned really well, because bacteria love to grow in old milk, which contaminates future feedings and increases disease risk,” Mike says.
Rumen development
To accelerate rumen development, you need hard feed and water. Young calves won’t get much nutrition out of solid feed such as hay or muesli initially, but even just nibbling a bit starts to introduce good bacteria to the gut and give something for the immature rumen muscles to start working against. At birth, it’s almost nothing, but by 12 weeks of age, the combined total of the calf’s stomachs is 20-30 litres, with the rumen accounting for 65%. By maturity, the combined total of the calf’s stomachs is 150-250 litres, with the rumen accounting for 80%.
“It is important for calves to eat some solid food like muesli or calf pellets. While they’re not getting much nutritional benefit from it in the first few weeks, it is driving rumen development, setting them up to get nutrition from solid feed and plant food once you wean them off milk,” Mike says.