Effect of Hypothyroidism on the Growth of Black Bengal Goats

Hypothyroidism was induced in three age groups (8 months, 1 year and 2 years) of Black Bengal goats by administering thiourea subcutaneously for 30 days. From fourth day onwards the animals were observed to be in hypothyroid state. For 8 months age group, a control group of similar age was taken. For the 1 year and 2 years age groups there was no control group but the values obtained on the pre-treatment day were considered as control values. For confirming the establishment of hypothyroidism, peripheral plasma triiodothyronine $(T_3)$ and thyroxine $(T_4)$ were estimated in all the animals before and during the treatment period by radioimunoassay. In the thiourea treated 8 months age group the $T_3$ and $T_4$ levels were significantly (p<0.001) lower than those in the control group during the treatment period. In all the thiourea treated groups the $T_3$ and $T_4$ levels observed during the treatment period were significantly (p<0.01) lower than the pre-treatment levels. A nonsignificant loss in the body weight was observed in all the thiourea treated groups whereas there was a significant growth in the control group of animals. The study indicates that hypothyroidism has a negative effect on growth in goats.