Comparison of ivermectin SR bolus, benzimidazole anthelmintics, and topical fenthion on productivity of stocker cattle from grazing through feedlot.

A study was conducted to determine the effect of different parasite control programs on weight gain and other measurements for stocker beef calves during the grazing season and subsequent feedlot phase of production. One hundred eighty recently weaned beef steers were purchased from a Mississippi sale barn and were allocated by restricted randomization on pretreatment weight to three treatments: (1) no anthelmintic treatment; treated only with a topical organophosphate (OP) during processing into the feedlot; (2) one benzimidazole (BZD) treatment at initiation of grazing, and a second given at the time of processing upon arrival at the feedlot, along with a topical OP; and (3) ivermectin sustained-release (SR) bolus administered at initiation of grazing, with no further treatment given at the feedlot. The cattle grazed separately by treatment for 125 days, with six replicated pastures per treatment; then were penned according to the same groupings after entry into the feedlot on day 127.

Safety of omeprazole paste in foals and mature horses.

Omeprazole has been shown to promote healing of spontaneously occurring gastric ulcers in horses when administered for 28 days at a dose of 4 mg/kg bwt/day and to prevent recurrence of ulcers in almost all horses when treatment is continued at a dose of at least 2 mg/kg bwt/day. The purpose of the 3 studies reported here was to 1) evaluate the evolution of potential effects of omeprazole paste (GastroGard), at a dose of 20 mg/kg bwt/day (5x the recommended dose) for 91 days in mature Thoroughbred horses; 2) evaluate the safety in young horses of omeprazole paste when dosed at 4 mg/kg bwt/day (1x), 12 mg/kg bwt/day (3x) or 20 mg/kg bwt/day (5x) for 91 days in Tennessee walking horse foals; and 3) evaluate the safety of omeprazole paste when dosed at 40 mg/kg bwt/day (10x) for 21 days in mature Thoroughbred horses. Within each study, horses were allocated randomly to the control or omeprazole paste treatment group.

Field trials evaluating ivermectin controlled-release capsules for weaner sheep and for breeding ewes.

Objective: To confirm the efficacy of ivermectin released from a controlled-release capsule administered to young sheep and to breeding ewes under field conditions.

Design: Randomised field trials.

Procedure: In each of ten field trials 25 weaned lambs were treated with ivermectin controlled-release capsules and 25 remained untreated.

Field trials in New Zealand confirming the efficacy of eprinomectin applied topically to cattle.

The efficacy and acceptability of eprinomectin in a topical formulation against gastro-intestinal nematodes in cattle was assessed under field conditions. Seven similar commercial dairy farms in the North and South Islands of New Zealand were included in the studies, involving 247 Holstein-Friesian, Jersey or Jersey-cross cattle. Cattle were confirmed by positive faecal nematode egg counts to have natural infections of gastro-intestinal nematodes and were held in separate treatment groups.

Efficacy of a pour-on formulation of eprinomectin (MK-397) against nematode parasites of cattle, with emphasis on inhibited early fourth-stage larvae of Ostertagia spp.

Objective: To evaluate efficacy of topically applied eprinomectin against inhibited early fourth-stage larvae (IL4) of Ostertagia spp in calves.

Animals: 4 groups (n = 6 [replicates]) for dose titration; 2 groups (n = 8 calves [replicates]) for dose confirmation.

Procedure: 2 dose titration studies-0, 125, 250, and 500 micrograms of eprinomectin/kg of body weight-Louisiana and Georgia- and 2 dose confirmation studies of selected therapeutic dosage (500 micrograms/kg) in Scotland and France.