Maternal dominance rank and secondary sex ratio in domestic swine
Article Abstract:
High ranking domestic swine gave birth to a greater proportion of sons compared with low ranking swine, a finding which supports a model proposed by Trivers and Willard, rather than the local-resource competition model, which predicts a higher proportion of daughters. The ratio of sons to daughters was not linked to size of litters, or age or breed of the sow, nor weight of the piglets, and rank of the sow was not related to the above factors either. Trivers and Willard's model also predicts that the rank of the mother will affect sons rather than daughters in terms of success in reproduction, and this aspect has yet to be tested
Publication Name: Animal Behaviour
Subject: Zoology and wildlife conservation
ISSN: 0003-3472
Year: 1993
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Mechanisms of sex-ratio adjustment in domestic swine: reply to James
Article Abstract:
Some of the views of William H. James regarding porcine sex ratios and sex combinations within the litters of the pig, Sus scrofa, invite comment. Differences in hormones besides those secreted by the adrenal glands will account for the sex ratios observed in the study. Hormonal differences do not always differ with the time of the fertile period. If so, the variance of the distribution of litters would be greater than that of the simple binomial distribution rather than smaller as in the sub-binomial distribution.
Publication Name: Animal Behaviour
Subject: Zoology and wildlife conservation
ISSN: 0003-3472
Year: 1998
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Testing models of adaptive adjustment of secondary sex ratio in domestic swine
Article Abstract:
D.B. Mendl, A.J. Zanella and D.M. Broom's analysis of the mechanisms that mediate the adaptive adjustment of domestic female swine to secondary sex ratios in relation to dominance ranks was erroneous. The study conducted by Mendl, Zanella and Broom was not valid because the female swine were removed from the context of their social ranks during a period that was critical for the adjustment of sex ratio. Furthermore, their evidence did not correlate with the Local Resource Competition Model.
Publication Name: Animal Behaviour
Subject: Zoology and wildlife conservation
ISSN: 0003-3472
Year: 1997
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