The influence of non-genetic factors on early growth traits in the Tygerhoek Merino lambs
2002
Gemeda Duguma (Ethiopian Agricultural Research Organization, Addis Abeba (Ethiopia). Department of Animal Sciences)S.J. Schoeman
Records of 8310 lambs born from 2538 ewes and sired by 681 rams covering the period 1970 to 1998 were used in the analysis of birth weight (BW), weaning weight (WW) and pre-weaning average daily gain (ADG). All three traits were affected (p0.001) by type of birth of lambs (single, multiple), six year of birth of lambs, group of animals (selection, control) and age of dam at lambing (2-to 6-year old). Male lambs and singles were heavier both at birth and weaning and grew faster (p0.001) than females and multiples, respectively. Non-selected animals were lighter than selected animals at birth and weaning with an inferior growth rate. BW increased with increasing dam age at lambing until a maximum of 3.7 kg was reached at 6 year of age, However, both WW and ADG reached a maximum at about 4 year of age of the dam.
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