One of the secrets to producing great calves lies in minimising the number of growth checks that they suffer. All management changes should happen gradually and at the right time; this requires a little bit of forward planning so that things go as smoothly as possible.
Invasive husbandry practices like dehorning are going to be stressful for calves and will temporarily suppress their intakes. Dehorning calves while they are still on milk will result in a smaller growth check than if they are dehorned after they are weaned. It’s also faster and safer for you to handle them when they are smaller.
Weaning calves off milk can cause problems as their rumen may not be developed enough to get all their nutrients from solid feed. Weaning on weight is a good way of ensuring that later born calves stay on milk long enough and don’t get left behind. DairyNZ recommendations are to wean calves at 80 – 100kg, depending on their breed.
Calves should have had access to high quality roughage right from birth in order to stimulate rumen development. Historically people fed hay or straw, but studies have shown that high protein meal is the best way to get the rumen going. Calf meal will usually also contain something to prevent coccidia, which can cause ill-thrift and scouring in young animals.
As soon as calves start eating pasture they will be picking up worms. It takes most worm species at least three weeks between being eaten and starting to shed eggs, this is why we recommend drenching young stock once a month. A dual action oral drench such as Arrest C is a very cost effective way to achieve good parasite control and minimise the build-up of resistance in young stock.
The wet cloudy weather recently has meant that pasture quality isn’t as high as we might like. This makes the milk and meal components of a calf’s diet even more important, and it might pay to hold off any weaning decisions until we’ve had a bit more sunshine.
When you do decide to wean calves off meal, make sure it’s done gradually. If calves have got a properly developed rumen there shouldn’t be a noticeable change to their growth rates, as they will be able to eat enough grass to compensate for the loss of the meal. A pre-ruminant calf is sometimes described as being round or ‘apple’ shaped when viewed from behind, and as their rumen develops they take on a ‘pear’ shape; wider lower down.
Remember that the meal has been preventing coccidia, and any scouring after meal is stopped should be investigated. Try to avoid weaning off meal at the same time as moving stock to run-off or to grazing, as the doubling down of stressors can make them even more susceptible to disease.
Before calves leave your property they should be up to date with all their vaccinations. This means two shots for blackleg and lepto, plus two shots for BVD if that is part of your BVD control strategy. You should be contacted by your local clinic soon to make sure that these are all done in time.
Weighing calves just before they go off grazing is a great way to check your own calf rearing, but also as a way to ensure that expectations with your grazier are clear. If you send well grown calves off grazing you should expect well grown heifers to come home, but if you send under-grown calves they may never be able to catch up to targets. If you can identify animals that might need a bit of extra help and preferentially feed them from the get-go then their prospects are much brighter than if they are identified later on.
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