Status of thyroid hormones in blood plasma of goats at different ages and their correlation with other biochemical parameters

摘要

Healthy female goats (156: 78 Barbari and 78 Jamunapari goats) of different age groups, managed under semi-intensive system of production in semiarid and tropical region were utilized. Blood was collected at days 0 (birth), 30, 90, 180, 270-300, 330-360 besides pre-pubertal, pubertal and post-pubertal (1 week after estrus) ages. Plasma concentration of thyroxine (T-4) and 3-3'-5-triiodothyronine (T-3) were significantly influenced by the breed and age of the goats. Significantly highest concentration of T-4 hormone in both the breeds was recorded at birth. After birth, T-4 level decreased sharply and attained significant lower values at 1 month of age in Barbari goats. In Jamunapari goats, T-4 concentration was lower at 30 and 90 days of age compared to all other stages. T-4 concentration started increasing after 1 month of age in Barbari goats and after 3 months of age in Jamunapari goats and remained at significantly high level up to 330-360 days of age. In Jamunapari goats, the highest level was also seen at the age of 270-300 days. At prepubertal, pubertal and post pubertal age, T-4 concentration did not fluctuate significantly. In Barbari goats, T-3 concentration did not change since birth to post-pubertal age except a decrease at 90 days age. In Jamunapari goats, T-3 concentration was generally stable except an increase at 180 days and pubertal age. The plasma T-4 and T-3 hormones were positively correlated with estrogen. T-4 had positive correlation with progesterone. T-3 hormone had significantly positive correlation with mean corpuscular haemoglobin concentration, serum glutamate oxaloacetate transaminase, serum glutamate pyruvate transaminase, amylase, total proteins, total globulin, cholesterol and estrogen.