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Author Feist, J.D.; McCullough, D.R.
Title Reproduction in feral horses Type Journal Article
Year 1975 Publication Journal of Reproduction and Fertility. Supplement Abbreviated Journal J Reprod Fertil Suppl
Volume Issue 23 Pages 13-18
Keywords Age Factors; Animals; Female; Horses/*physiology; Leadership; Male; Maternal Behavior; Population; Reproduction; *Sexual Behavior, Animal; Social Dominance; Sucking Behavior
Abstract A behavioural study of feral horses was conducted on the Pryor Mountain Wild Horse Range in the western United States. All 270 horses on the Range were identified individually. The sex ratio was nearly balanced. Foal to adult female ratio was 43-2:100. Morality was concentrated among foals and old horses. Horses were organized as forty-four harem groups each with a dominant stallion, one to two immature stallions, one to three immature mares, one to three adult mares and their yearling and foal offspring, and 23 bachelor groups of one to eight stallions. Harem groups were quite stable year-round because of dominance and leadership by the stallions and group fidelity by mares and their offsring. Most changes occurred during the breeding season and involved immature females. Defeat of dominant stallions was infrequent. Immature males were tolerated because of their submissive behaviour. Bachelor stallion groups were inherently unstable. Mares came into heat after foaling in May/June, and were mated by harem stallions only.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language (up) English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0449-3087 ISBN Medium
Area Expedition Conference
Notes PMID:1060766 Approved no
Call Number refbase @ user @ Serial 1964
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Author Belonje, P.C.; van Niekerk, C.H.
Title A review of the influence of nutrition upon the oestrous cycle and early pregnancy in the mare Type Journal Article
Year 1975 Publication Journal of Reproduction and Fertility. Supplement Abbreviated Journal J Reprod Fertil Suppl
Volume Issue 23 Pages 167-169
Keywords Animals; Body Weight; *Diet; *Estrus; Female; Fertility; Fetal Resorption/prevention & control; Horses/*physiology; Pregnancy
Abstract Attention is drawn to the beneficial effect of improved nutrition during winter and early spring on the ovarian activity of mares. Furthermore, the necessity of an adequate plane of nutrition during early pregnancy to prevent embryonic resorption is stressed.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language (up) English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0449-3087 ISBN Medium
Area Expedition Conference
Notes PMID:1060772 Approved no
Call Number Equine Behaviour @ team @ Serial 2225
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Author Lucas, Z.; Raeside, J.I.; Betteridge, K.J.
Title Non-invasive assessment of the incidences of pregnancy and pregnancy loss in the feral horses of Sable Island Type Journal Article
Year 1991 Publication Journal of Reproduction and Fertility. Supplement Abbreviated Journal J Reprod Fertil Suppl
Volume 44 Issue Pages 479-488
Keywords Abortion, Veterinary/*epidemiology; Animals; Animals, Wild/*physiology; Atlantic Islands; Estrogens/analysis; Feces/chemistry; Female; Fertilization; Gestational Age; Horse Diseases/*epidemiology; Horses; Incidence; Pregnancy; *Pregnancy, Animal
Abstract Field observations of 400 totally unmanaged feral horses on Sable Island, Nova Scotia, were complemented by oestrogen determinations in faecal samples from 154 identified females over a 4-year period (454 mare-years). Of mares that were sampled throughout the year and subsequently produced foals, 92.1% exhibited elevated faecal oestrogens between 15 October and 30 March. The results confirm that faecal oestrogens are a useful indicator of pregnancy after approximately 120 days gestation. Distribution of foaling resembled that seen in other feral populations, with 95% of births occurring from April through July. The foaling rate for mares aged 3 years or older was 62.0%, with 50.7% of mares foaling in 3 or 4 years. Foaling rates were low (4.1%) in mares bred as yearlings and rose with age to 70.8% in those bred as 4-year-olds. Fetal loss after Day 120 was deduced from faecal oestrogens to be 26.0% overall, with marked variation from year to year (9.6-37.3%) and with age (70.0% in those bred as yearlings, decreasing to 5.6% in those bred as 4-year-olds). Of 58 mares aged 2 years or older that were sampled every year, about half (49.6%) the barren years were attributable to fetal loss after 120 days gestation. All mares conceived in at least 2 of the 4 years, suggesting that pregnancy loss, even after Day 120, is as important as failure to conceive in causing barren years.
Address Department of Biomedical Sciences, Ontario Veterinary College, University of Guelph, Canada
Corporate Author Thesis
Publisher Place of Publication Editor
Language (up) English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0449-3087 ISBN Medium
Area Expedition Conference
Notes PMID:1795292 Approved no
Call Number Equine Behaviour @ team @ Serial 2247
Permanent link to this record