Title: Drug Treatment for Lungworm in Bighorn Sheep: Reevaluation of a 20-Year-Old Management Prescription
Abstract:We conducted a 4-year management experiment to examine the annual effects of alternative management treatments, including anthelmintic administration, on lamb survival in Rocky Mountain bighorn sheep ...We conducted a 4-year management experiment to examine the annual effects of alternative management treatments, including anthelmintic administration, on lamb survival in Rocky Mountain bighorn sheep (Ovis canadensis canadensis) herds in southcentral Colorado. Beginning in December 1991, 4 bighorn herds were managed under alternative treatment regimes: baiting with alfalfa hay and apple pulp treated with fenbendazole (BT), baiting with alfalfa hay and apple pulp without fenbendazole (B), placing fenbendazole-treated salt blocks on winter ranges (T), and both withholding bait and fenbendazole (control; C). Treatments were rotated annually under a predetermined, randomly-selected schedule. Mean lamb production, survival, and recruitment rates did not differ among herds or years. None of the management treatments produced demonstrable improvements in lamb production, survival, or recruitment. Estimated effects (±SE) of treatments on lamb production and survival were small (≤0.09 ± 0.18). Annual recruitment rates (lambs/marked ewe) through October ranged from 0.13 to 0.88, but overall recruitment rates (mean; 95% CI) for B (0.72; 0.55-0.90), T (0.71; 0.47-0.95), and BT (0.52; 0.08-0.97) were indistinguishable from C (0.62; 0.19-1.0). Sick and coughing lambs were observed every summer in 1 herd and 1 summer in a second. Our results demonstrate that annual parasite treatment is not prerequisite for acceptable lamb survival among southcentral Colorado's wild bighorn populations, and that annual parasite treatment may not prevent catastrophic losses of lamb cohorts. Based on these data, we question the need for annual baiting and parasite treatment in the herds studied here and recommend such practices be reevaluated elsewhere.Read More
Publication Year: 2000
Publication Date: 2000-04-01
Language: en
Type: article
Indexed In: ['crossref']
Access and Citation
Cited By Count: 55
AI Researcher Chatbot
Get quick answers to your questions about the article from our AI researcher chatbot