Effect of a peri-parturient eprinomectin treatment of dairy cows on milk production.

Aim: To quantify and economically evaluate the effect on milk production of peri-parturient treatment of dairy cows with eprinomectin.

Methods: On 3 farms in separate geographic areas of New Zealand, 849 first-calf heifers and multiparous cows were ranked and paired within parity, date of calving and expected milk production. Within pairs, cows were randomly allocated to treatment with either a commercial formulation of eprinomectin, applied at a dose rate of 500 mug/kg liveweight, or an equivalent volume of vehicle containing no antiparasitic agent and administered at the same dose volume, generally within the first week post-calving.

An evaluation of the quality and physical properties of calf leather following topical application of eprinomectin.

The gross and histological appearance of skins obtained from twelve 6-10 month-old Friesian X Hereford calves 14-15 days after they were treated with a topical formulation of 0.5% eprinomectin administered at 1 ml per 10 kg bodyweight was compared to that of skins from twelve untreated controls. No significant differences were observed and there were also no significant differences in the quality and physical properties of leather produced from the skins of treated and untreated groups, indicating that topical eprinomectin has no deleterious effects on the leather quality of calf skins.

Tick control: an industry point of view.

The development of new acaricides is a long and very expensive process. Worryingly, there is increasing resistance to available acaricides worldwide leading to the real possibility that our dwindling supply of effective acaricides will be exhausted unless action is taken to increase the number of new acaricidal products and reduce the rate of resistance development. In 1995, eight major animal health pharmaceutical companies formed the Veterinary Parasite Resistance Group (VPRG) to act as an expert consultative group to guide the FAO in resistance management and collaborate in the prudent use of acaricides.

Persistent efficacy of topical eprinomectin against nematode parasites in cattle.

Six studies were conducted to evaluate the persistent efficacy of eprinomectin pour-on against experimental challenges with infective nematode larvae in calves. In each study, calves were randomly assigned to one untreated group and up to four test groups, which were treated with eprinomectin at 500 microg/kg body weight at weekly intervals before single bolus challenge. The calves were necropsied approximately 4 weeks after challenge infection for nematode recovery.

Efficacy of ivermectin in a controlled-release capsule for the control of breech strike in sheep.

Objective: To investigate the efficacy of ivermectin in an intraruminal controlled-release capsule (CRC) against blowfly strike.

Design: Pen and field trials with controls.

Animals: Pen studies: Two breech strike trials involving 60 Romney and 60 Merino sheep.