Changes sought over drench doses

Goat farmer Bill Campbell, of Dumbarton, Central Otago, said the goat fibre industry was facing a drench resistance problem. Photo by Yvonne O'Hara
Goat farmer Bill Campbell, of Dumbarton, Central Otago, said the goat fibre industry was facing a drench resistance problem. Photo by Yvonne O'Hara

Goat fibre farmers Bill and Irene Campbell, of Dumbarton, Central Otago, will be showcasing their 500-goat flock to delegates from the inaugural New Zealand Goats (NZGoats) conference on Friday.

One of the topics of conversation is likely to be drench resistance.

''It is a big problem within the industry and I believe that most angora goat farmers have problems with it,'' Mr Campbell said.

He said he would like to see the drench manufacturing companies research the correct dosage rates and withholding periods for goats and include them on the tables on the drench products.

However, he was not optimistic that would happen, as the research process would be an expensive exercise for the companies and there were not enough goats in the national flock for it to be cost-effective.

He said some farmers were delivering one-and-a-half times to twice the recommended dose per 10kg of liveweight and that practice was encouraging drench resistance.

However, he said he and his wife kept to the recommended dose, as per the label.

He would also like to see a drench gun developed that had finer increments of 1ml markings, similar to an inoculation gun.

''We drench with a syringe, not a drench gun, as they are not accurate enough,'' Mr Campbell said.

He said they weighed a few of the animals in their flock at drenching time to get an eye for the weight, then eye-appraised the rest and then determined the amount of drench that each individual animal should receive.

''Goat farmers should not give the same drench amount to every animal.

''Each animal should receive the correct dose, according to its weight, whereas a standard drench gun gives an average dose, according to the heaviest animal.

''Alternatively, they should draft animals according to weight range.''

They have been rearing goats since 1986 and will drench during the autumnal high pressure season for parasites, and when they think their animals need it.

Drenching starts from 3 months of age to 2 years.

''Our policy is to drench all those that need it, but we do lose the odd one,'' he said''Anything that is big and healthy is not drenched.

''Some goats can be healthy one day and four days later have a big worm burden.

''When we start to see a few dirty bums, hollow guts, tails down and slow moving, and then we drench.''

The goats are usually drenched once with a single dose, but if there is no noticeable results after about three weeks, they would then consider drenching twice in a 24-hour period, with one of the drenches being a combination drench.

They also use two different families of drench, so if they do not get a 100% kill with one, the other will hopefully take care of the survivors.

''We get good results with this programme, without resorting to increasing dose rates,'' he said.

''Drench resistance could put the goat industry in jeopardy if we don't get right.''

- by Yvonne O'Hara