Calves are starting to go out onto pasture, which means that now is a good time to make a drench plan. Calves start ingesting worms as soon as they start eating grass and will start shedding eggs about three weeks after that. The pasture around the calf shed will very quickly become contaminated, and calves coming out later in the season can be subjected to a very high parasite challenge.
Along with good feeding and trace element supplementation, a comprehensive drench program is an important part of getting good growth from your calves and yearlings, which means regular treatment with the right products. When considering what treatments are best for you a few points to consider are:
- Oral drenching works best in young calves, is cheaper than the alternatives, and should be done every month until it becomes physically too difficult to wrestle the calves, usually when they’re about 120kg.
- Drenches should always be a combination product with at least two active ingredients, as these will be more effective than single actives and will slow the development of resistance on your farm.
- POUR ON PRODUCTS ARE NOT SAFE FOR YOUNG CALVES as they often have a relatively low safety margin and can easily be overdosed. Pour on drenches should only be used on calves over 120kg
- Consider leaving calves that have achieved target condition or better, and in good health, untreated. This helps to slow the development of resistance to drenches as well as saving money
- With older calves and yearlings ideally treatments with a combination of active ingredients should still be used, while the interval between treatments will change based on product used, the likely challenge to stock from worm larvae in summer and their first winter and the achieving target weights
- As well as ensuring they’ve been getting adequate copper and selenium supplementation it’s worth giving your rising 2 year olds a pre-mating drench, especially if they’re on a property that regularly grazes other young stock.
An effective worming program can save money and achieve better young stock weights – talk to your vet about what’s best suited to you and your farm