EFFECTS OF COLD EXPOSURE ON YOUNG GROWING LAMBS

Abstract

The performance and development of young Iambs housed at 0 ± 1 °C or 21 ± 1 °C were compared in two experiments. Despite similar nutrient intakes for both treatment groups, preweaning growth rate of the cold-exposed lambs tended to be reduced. Bone growth from 4 to 9 wk of age revealed a significant effect of temperature on metatarsal length (P < 0.05). By 10 wk of age morphological differences between the two groups were apparent, especially in terms of smaller ear dimensions (P < 0.01), head (P < 0.10) and metatarsal lengths (P < 0.05) of the cold-exposed lambs. Leg bone lengths after slaughter (13 wk of age) also tended to be shorter for the lambs housed at 0 °C. Organ weights measured after 11 wk of differential temperature exposure were similar for both groups except for slightly increased abomasal and thyroid weights (P < 0.10) in the cold-exposed group. Dry matter and nitrogen digestibilities of a concentrate ration fed to the weaned lambs were not affected by treatment, although nitrogen retention (g/day, g/g digestible N intake) was significantly lowered (P < 0.05) as a result of cold exposure. Key words: Cold, growth, digestion, morphology, lambs