Non-genetic factors influencing early growth traits in the Elsenburg Dormer sheep stud

Abstract

Records of the Elsenburg stud where the Dormer sheep breed originated in 1941, were analysed from 1941 to 1990 to investigate non-genetic factors contributing to early growth traits. The fixed effects, identified as having a significant (P < 0.01) effect on birth weight, weaning weight, average daily gain and Kleiber ratio, were year-season, age of darn, sex, birth status and level of inbreeding. Although some significant interactions were found, they were subsequently ignored owing to their very small effects. A model best describing the data, which can be used for further analyses, is constructed and discussed. It is advocated that the uniqueness of each population and situation necessitates such an analysis in each specific case.

Rekords van die Elsenburgstoet waaruit die Dormerskaapras in 1941 ontstaan het, is van 1941 tot 1990 ontleed om die moontlike bydraende nie-genetiese faktore op vroeë groei-eienskappe te ondersoek. Die vaste effekte wat 'n betekenisvolle (P < 0.01) invloed op geboortegewig, speengewig, gemiddelde daaglikse toename en Kleiberverhouding het, sluit jaar-seisoen, ouderdom van ooi, geslag, geboortestaat en vlak van inteling in. Sekere betekenisvolle interaksies is verkry, maar is weens geringe effekte geïgnoreer. 'n Model wat die data die beste pas en vir verdere analises gebruik kan word, is saamgestel en word bespreek. Die uniekheid van elke populasie en situasie noodsaak 'n soortgelyke analise in elke spesifieke geval.

Keywords: Dormer sheep, early growth traits, non-genetic factors