Preweaning Environment Research Articles

Crossbreeding beef cattle in Western Uganda. 2. Environmental influences on body weight

SUMMARYThe nine possible breed types resulting from the use of Angus, Boran and Red Poll bulls on Ankole, Boran and local Zebu cows were represented in the experiment. Sex, period of birth and year of birth had significant effects, at practically all ages, on body weights of calves measured at three-monthly intervals from birth to two years. Age of dam had a significant effect on calf weight at birth but not thereafter. Previous parous state of dam had only few apparently significant effects on calf weights at different ages. It appeared that beneficial effects of a good pre-weaning maternal environment might be retained, as there was no strong evidence of post-weaning compensatory growth for pre-weaning maternal effects due to age and previous parous state of dam.

Comparison of background stimulation and handling as forms of infantile stimulation.

Between birth and weaning rats ( N = 92) were housed in the laboratory maternity room or in a separate quiet room; half were handled, the other half not disturbed; after weaning half were reared in the laboratory colony room while half were put into the quiet room. Weaning weight was significantly reduced by handling and by being reared in the quiet room; adult weight was an interactive function of handling and the preweaning environment. Handled Ss and those reared in the quiet room postweaning were significantly more active in the open field. Open-field defecation was significantly reduced if S spent at least some time in a quiet environment. The data refute the hypothesis that stimulus input from the surrounding environment during infancy has the same functional effects as does handling. However, the ambient environment does play a dynamic role in the shaping of future biological and behavioral processes.