Longevity is the amount of time breeding females stay active in a herd by avoiding death or culling because of illness or reproductive failure. This is a trait of economic relevance in commercial small ruminant breeding herds as it affects lifetime reproductive output. The purpose of this study was to determine if breed of meat goat influences breeding doe survival rates and cumulative reproductive performance under semi-intensive management.
Boer (n=132), Kiko (n=92) and Spanish (n=79) does were evaluated for longevity trends and cumulative kid production. The herd was managed on humid subtropical pasture. Does had the chance to complete 2 to 6 production years. Survival curves were analyzed for 2 culling methods. The actual culling practice removed does after two failures to wean a kid. An alternative culling protocol removed doe records after the first failure to wean a kid. Kid production traits analyzed across herd life were the total number of kids weaned and cumulative kid weight weaned to the 2-, 3-, and 5-year stayability endpoints. Most (82%) doe exits were illness-related under the actual culling method. Reproductive failure represented 51% of doe exits under the alternative culling protocol. Boer does had greater survival declines (P<0.01) from 2 to 6years of herd life compared with Kiko and Spanish under both culling protocols. Boer does had lower stayability rates (P<0.01) at each year endpoint for both culling protocols. Under the alternative protocol, over 50% of Boer does failed to complete 2years, whereas over 50% of Kiko and Spanish does successfully completed 4years. Boer does had lower (P<0.01) total number of kids weaned and cumulative weight weaned through each stayability endpoint compared with Kiko and Spanish.
Boer does had low stayability and cumulative kid production rates compared with Kiko and Spanish does. Poor health was the primary driver of does exiting the herd. Kiko and Spanish does did not differ for longevity and lifetime performance indicators.
Keywords: Meat goats, Boer, Longevity, Lifetime performance, Adult, Mortality, Reproduction