Doramectin efficacy against the kidney worm, Stephanurus dentatus in sows

Sixteen sows passing Stephanurus dentatus eggs in their urine were bought on the local market and placed in individual pens with solid concrete floors in an open-sided bam. Water was supplied by nipple waterers and sows were fed individually 1.8 kg feed daily. First, urine samples were taken at dawn on days -8 and -7 and weights were taken on day 0. Sows were assigned to one of two groups on the basis of average urine egg counts and weights. Group T1 sows were each injected IM in the neck with sterile saline at the rate of 1.5 ml per 50 kg and group T2 sows were each injected IM with doramectin at the rate of 300 micrograms kg-1 on day 0. Urine samples were again taken on days 56 and 57 and the sows were necropsied on day 57. Urine of all doramectin treated sows were test negative for kidney work eggs on days 56 and 57 as was one control sow, whereas the average count for controls was 3762 eggs ml-1. No worms were found in doramectin treated sows and a total of 499 were found in the controls for an average of 62 per sow. The majority of worms were in the perirenal area and kidneys, a few were scattered in liver, lungs, abdominal muscles and peritoneal cavity. The efficacy of doramectin against Stephanurus dentatus in sows was 100% (P < 0.0001).