Open AccessPopulation structure and dynamics in captive muskoxen at the Large Animal Research Station, 1988-1994
Author(s) -
Robert G. White,
Janice E. Rowell,
John E. Blake,
William Hauer
Publication year - 1998
Publication title -
rangifer
Language(s) - English
Resource type - Journals
eISSN - 1890-6729
pISSN - 0333-256X
DOI - 10.7557/2.18.3-4.1458
Subject(s) - ice calving , sex ratio , population , offspring , zoology , biology , pregnancy , perinatal mortality , demography , fetus , lactation , genetics , sociology
The muskox colony at the Large Animal Research Station, started in 1979, totaled 22 individuals before calving in 1988. Between 1988 -1994 cows of breeding age have been maintained on either a high plane (HP) or low plane (LP) of nutrition, and as far as possible, female offspring are kept with their mother's group. During this time the population has increased from 22 to 43 animals (25 females and 18 males). Fifty-four calves were born with an overall sex ratio of 52:48 (male:female). When partitioned between the 2 nutritional planes the sex ratio was HP 45:55 and LP 62:38. The calf/cow ratio was 0.83 in 1988 and 0.86 in 1994. The LP group accounted for most of the variability in pregnancy rate, primarily through delayed puberty and breeding pauses. Calf mortality was due mainly to abortions, stillbirths and neonatal death (n=12), 7 deaths occurred between 2 weeks and 1 year of age. All stillbirths and abortions (n=4) and 6 of 8 neonatal deaths affected calves of HP cows. Thirteen adults died, 4 males were loaned to other facilities and 2 new calves were added