Abstract
Since 1967, four generations of muskoxen have been born in captivity in Alaska (399 live births, 18 abortions and 47 stillbirths), all derived from 20 females and 8 males captured on Nunivak Island. Analysis of juvenile survival was accomplished by dividing individuals into 7 classes (not born live, born live but not surviving 48 hours, survived 48 hours but < 1 week, survived 1 week but < 1 month, survived 1 month but < 6 months, survived 6 months but < 2 years, survived 2 years). Males were more frequent among live born calves (219:178, P=0.05), but greater numbers of females survived to 2 years (62:86, P<0.01). Birthweight (X=9.75 kg, N=155) did not differ between sexes nor did it significantly influence survival. Of 463 individuals, 131 showed some inbreeding but no coefficients of inbreeding exceeded 0.25 and most were less than 0.13. Analysis of variance (Kruskal-Wallis) showed a significant (P<0.05) difference between survival of inbred and non-inbred individuals. Chi-squared tests showed a greater proportion of non-inbred calves surviving to 2 years (P<0.05) but no significant differences in perinatal mortality. Offspring of the Nunivak Island cows survived significantly (P<.01) longer than those whose mothers were born in captivity, even when only non-inbred calves were compared.
Highlights
Introduction knitters in rural Alaskan villagesOver theIn 1964 and 1965 a total of 10 male and 23 fe- years both the location of the animals being male muskox (Ovibos moschatus) calves was bro- bred for domestication and the organization reught from Nunivak Island, Alaska, to the U n i - sponsible for the domestication project have versity of Alaska near Fairbanks
The material for our analysis comes from records kept on four generations of muskoxen born in captivity in Alaska from 1967 to 1989
Following the convention used for most studies of inbreeding in which the exact relationship among founder individuals from a wild population is unknown, these individuals were considered unrelated to each other-and the calves whose mother and father were both born in the wild on Nunivak Island were assigned coefficients of inbreeding equal to 0
Summary
The material for our analysis comes from records kept on four generations of muskoxen born in captivity in Alaska from 1967 to 1989. In almost all cases individual medical records were kept, giving details regarding the cause of death, if known. Following the convention used for most studies of inbreeding in which the exact relationship among founder individuals from a wild population is unknown, these individuals were considered unrelated to each other-and the calves whose mother and father were both born in the wild on Nunivak Island were assigned coefficients of inbreeding equal to 0. These founder animals were in some degree related to one another.
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