Synergy Factors in the Analysis of Lamb Survival

Abstract

Survival is one of the most important traits in genetic improvement programmes in livestock. The objective of this study is to determine sex, inbreeding, and birth type effects as well as their interactions on birth survival in lambs of two breeds. Records of 6356 Polish Merino (PM) breed and 9143 Wielkopolska sheep (WS) were taken into the analysis. Relationships between survival and three binary variables (sex, inbreeding, type of birth) were estimated by the use of logistic regression. Interactions among these variables were also included in the model. Thus, the odds ratios and synergy coefficients were estimated. Lowest birth mortality was registered for inbred females from single birth. Differences in survival between the studied breeds were observed. Negligible single effects of sex, inbreeding and birth type for PM were estimated, whereas for WS these effects were significant (P<0.01). Opposite dependencies were obtained for interactions among these variables. In the case of PM, synergy between birth survival and joint effects of sex-inbreeding, sex-birth type, sex-inbreeding-birth type were highly significant, but for WS only inbreeding-birth type interaction was considerable. Hence, a generalisation of the obtained results seems to be difficult: they exhibit a very complex background of lamb survival.

Genetic analysis of longevity and lamb survival from birth to yearling in Moghani sheep

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Effects of inbreeding, sex and geographical region on survival in an American bison (Bison bison) population under a captive breeding program

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>b<Suplementação de ovelhas no terço final de gestação e lactação com propionato de cromo>/b<

“…A necessidade fisiológica basal do mineral para manutenção das suas atividades é atendida naturalmente através da dieta (DȨBSKI et al, 2004;LINDEMANN, 1999;VINCENT, 2010). No entanto, a ingestão suplementar diária de 0,5 a 0,7 mg de Cr promove benefícios nos efeitos do estresse e no crescimento de bovinos (AMATA, 2013 SOUSA, 2014;KENYON et al, 2011;TOMASZYK et al, 2014). A taxa de crescimento fetal e o volume uterino aumentam consideravelmente no último terço de gestação.…”