Livestock Guard Dogs Reduce Predation on Domestic Sheep in Colorado

We surveyed the effectiveness of livestock guard dogs for reduc-ing predation on domestic sheep in Colorado during 1993. The number of producers using dogs increased from about 25 in 1986 to >159 in 1993. The proportion of sheep with dogs increased from about 7% in 1986 to about 68% in 1993. Producers with dogs, compared to producers without dogs, lost smaller proportions of their lambs to predators, especially coyotes (Canis latrans Say), and smaller proportions of ewes and lambs to black bears (Ursus americanus Pallas) and mountain lions (Felis concolor L.). Overall, producers who did not have guard dogs lost 5.9 and 2.1 times greater proportions of lambs to predators than producers who had dogs in 1986 and 1993, respectively. Proportions of sheep killed by predators decreased with the number of years that producers used guard dogs. Mortalities of ewes to predators regardless of type of operation and lamb mortality on open range decreased more from 1986 to 1993 for producers who obtained dogs between these years compared to producers who did not have dogs. Of 160 producers using dogs, 84% rated their dogs overall predator control performance as excellent or good, 13% as fair, and 3% as poor. More producers (n = 105) indicated effectiveness of their dogs did not change with time, compared to producers (n = 54) indicating effectiveness changed. More producers (n = 35) also indicated their dogs became more effective over time compared to producers (n =19) indicating their dogs became less effective. Estimates provided by 125 producers indicate that their 392 dogs saved 891,440 of sheep from predation during 1993. A total of 154 of 161 (96%) producers recommend use of guard dogs to other producers.