Carry on worming when
PRODUCERS still grazing stock should continue worming until housing, advises Dr Mike Taylor, head of parasitology at the Central Veterinary Laboratory.
He says the dry summer and mild autumn has caused a build up of larvae on grass in many parts of the country. "Cattle and sheep still outside are in danger of picking up large numbers of infective worm larvae which could lead to disease now, or to problems next spring.
Yearling cattle and sheep may be particularly susceptible this autumn to gutworms, especially those causing "black scour", and producers should watch for scouring or ill-thrift, says Dr Taylor.
He emphasises the importance of drenching stock at housing with an anthelmintic effective against dormant or arrested worm larvae. Producers forced to turn out animals during winter should be aware that parasite larvae are capable of over-wintering on the pasture and are a constant source of infection, he adds. In these situations further treatments may be necessary.
Although most anthelmintics used for gutworms are also effective in removing lungworms, he advises producers concerned about lungworm that "vaccination of calves prior to turnout in the spring is the most effective method of control". Anthelmintic treatment on housing may, however, help limit lungworm numbers in carrier animals, he says, and reduce pasture contamination next spring. Liver fluke was likely to be a low to moderate problem in much of the country according to recent predictions. "Where disease exists the timing and frequency of treatment will depend on the product used and vet advice should be sought."
Build up of many external parasites occurs throughout the winter and this is when diseases associated with lice, keds or mange mites are usually at their worst. "Although some newer wormers have activity agasinst ectoparasites, none are completely effective against all types and more specific insecticidal treatments may be required. Signs of itching, or wool or hair loss should be investigated and treated. It pays to involve your vet in determining the cause and selecting the most appropriate treatment," says Dr Taylor.