This year NZAgbiz has partnered with Fonterra and AgResearch to host a series of live-stream interactive webinars with farmers.
The recent webinar, “Raising Calves and Lambs”, was well attended with farmers from around the country tuning in to listen to Fonterra’s Senior Vet Michael Shallcrass, Senior Scientists Sue McCoard and Ajmal Khan from AgResearch, and NZAgbiz National Sales Manager Carla Rawson.
Topics included feeding quality colostrum, diet transitions, what and how much milk you should feed, disease, hygiene and animal health plan considerations when artificially rearing calves and lambs.
Collecting, storing, and feeding colostrum
Michael Shallcrass kicked off the webinar with a discussion about the importance of colostrum.
“Gold colostrum is the very first milking after a cow or ewe has given birth. It is called gold because it is yellowish in colour compared to normal milk. It has a Brix reading of >22% for cows or >25% for ewes. It is super concentrated and very high in energy, fats, proteins and immune compounds (immunoglobulins),” he says.
“Calves and lambs are born with an undeveloped immune system and those immune compounds in colostrum are essential for transferring immunity from the mother to her young. The first 24 hours are essential. New-born ruminants lose that ability to absorb those immune compounds shortly after birth so you only get one shot with each animal to give their immune system that head start,” he says.
Colostrum is often pooled and stored for future use so farmers can ensure calves receive the best colostrum and the required amount. It is essential that the colostrum is stored in clean drums to avoid bacterial contamination. If you have frozen colostrum, take care when defrosting to ensure the product stays usable and doesn't get cooked.
Carla Rawson pointed out there are a number of options available for farmers who find their colostrum isn’t quite at gold standard including NZAgbiz’ JumpStart™, which will give calves the required number of immunoglobulins and antibodies.
Research has found that calves fed only silver colostrum (from second or third milkings) often experience more disease, have compromised growth, and lower feed efficiency.
“This will have long-term consequences on the performance of these calves. Farmers need to consider three Qs – the quality of the colostrum; the quantity you are feeding – twice daily if possible; and be quick – achieve the colostrum feeding in the first 24 hours,” says Ajmal Khan.
How do you know it’s working?
Michael says farmers can check if their process is working by getting vets to take blood tests from calves to assess the total protein levels and ensure that the calves received enough colostrum in that critical 24-hour period post-birth. This is particularly important if you are buying calves from other farms.
Transitioning to milk
Minimising stress on calves and lambs is critical when it comes to transitioning to milk. Carla says a good rule of thumb is to “do one change at a time”.
“If you are moving to milk replacer, keep some of your transition milk (milkings two to eight) aside. You can then drop 25% of the transition milk at a time and put in 25% milk replacer; then 50/50 split, then 75/25. By day four the calf will have moved from transition milk to replacement milk completely,” she says.
NZAgbiz has a calculator on their website to help farmers determine the exact amounts of transition milk and milk replacer each day to suit their herd.
Sue says that “lambs ideally should be fed at 20-25% of their initial body weight, 3-4 times a day from two days of age when they are removed from the milking ewe following lambing.”
Calves ideally should be fed twice a day. A calf left with its mother will feed eight to 12 times a day. Michael says farmers can feed a calf once a day over its first three weeks but it may not meet its nutritional requirements. Instead, farmers are better off feeding a larger total volume split between two feeds so that they can optimise growth.
“The more you can feed them, the better the lifetime performance of that animal,” he says.
Feeding twice a day or more also relieves pressure on the calf’s digestive system. The amount of feed will depend on the breed and weight of the animal. Research suggests feeding a calf 15-20% of their initial body weight (birth weight) split between two or three feedings is ideal.
The ideal milk replacer should have about 15% milk solids and farmers should be aware of the mixing rates of different products. Using warm water to mix the milk replacer can save the calf’s energy in digesting the product.
Transitioning to solid feed
A calf’s rumen develops from around five weeks of age. Sue McCoard says research has found there is no detrimental effect on rumen development if calves are fed milk right up to 10 weeks of age provided there is access to good quality solid feed and a gradual weaning process.
“Ideally keep the milk up as high as you can for at least the first six to seven weeks and then start the weaning process at around eight to 10 weeks. That weaning transition is really important to ensure you’re not having a negative effect on the rumen and metabolic function of the animal.”
A guide is to reduce milk replacer over two to three weeks and continue to feed them the same high-quality pasture and/or supplements they have been fed prior to milk replacer weaning. Gradual weaning off starter diets/supplements is also important. Calves continue to grow for the first few years, but there's a big risk of growth problems over their first summer as feed quality drops off. To maintain feed quality post-weaning through summer, consider adding meal back in if grass quality drops away.