Influence of Diet and Season on Plasma Thyroidal Hormones in Growing Buffalo Calves

An experiment was conducted, on 12 female buffalo calves divided into two groups of 6 each, to study the effect of undernutrition and seasonal stress on plasma thyroxine (T₄) and triiodothyronine (T₃) concentration. The group 1 calves were fed as per their standard requirements and the calves of group II received 39% less CP and 18% less TDN for one year. The year was divided into summer, hot-humid and winter seasons. The body weights at the start and end of the experiment averaged 116.66, 317.00 and 116.33, 253.33 kg in group I and II, respectively. The plasma T₃ and T₄ concentrations (P <0.01) and growth rate (P<0.05) were significantly influenced by the level of nutrition and season. The plasma T₃ and T₄ concentrations were positively correlated with weight gain.