Effect on performance of weanling alpacas following treatments against gastro-intestinal parasites.

Nematodes and coccidia are common parasites of alpacas (Vicugna pacos), and important causes of disease in this increasingly popular livestock species. Endoparasitic infestation is thought to increase at times of natural or imposed stress, and antiparasitic treatments are often administered, although to date there is little evidence regarding their effect. Thirty-one alpaca juvenilles (cria) were divided into four groups at weaning, and received either no treatment as a control (C), fenbendazole anthelmintic (FB), toltrazuril coccidiostat (T), or both treatments (FBT). Body weights and faecal egg/oocyst counts were recorded weekly for six weeks following treatment. Although the prophylactic treatments decreased faecal egg/oocyst counts of the target organisms in the short term, there was no significant difference in egg/oocyst output over the course of the trial from animals given wormer, coccidiostat or both treatments. The group receiving anthelmintic only showed a significant reduction in live weight gain (LWG), with no significant difference in LWG between the other groups. At the conclusion of the trial, 'wormed only' alpacas weighed 3.3% less than at weaning, losing an average 1.3 kg over six weeks, whereas average LWG in the control group was 2.5 kg. Antiparasitics transiently reduced egg/oocyst output but results suggest that further investigation is required on the action of anthelmintics administered to alpaca cria at weaning and their effect on animal health and welfare.