Changes of serum concentrations of cortisol and thyroid hormones and their correlation during pregnancy, lactation and dry periods in Saanen goats

The importance of serum concentrations of cortisol and thyroid hormones in metabolic process have been emphasized since old days. Aim of this study is to investigate the analysis of serum concentrations of cortisol and thyroid hormones and the correlation between them during lactation, pregnancy and dry periods in Saanen goats. A total of twenty female adult Saanen goats at age of 3 years with a body condition score of 3.5 (in the beginning of experiment) and average weight of 30.2±2.20 kg were selected. The animals were reared under the same management conditions and definite feeding program (according to their maintenance and physiologic demands). The whole duration of the study was divided into three periods including dry (non-pregnant) period, four-month single pregnancy (at the end of the fourth month) and lactating period. Serum concentrations of cortisol were increased and those of thyroid hormones were decreased significantly (p