comparison of serum triiodothyronine, tetraiodothyronine and thyroid stimulating hormone concentrations in pregnant and lactating beetal-cross and native goats in garmsar township

Background: the preliminary survey made about congenital goiter in goats in garmsar township indicated that the disease occurs much more in beetal-cross than native goats raised in the same area. objectives: the aim of the present study was to compare serum triiodothyronine (t3), tetraiodothyronine (t4) and thyroid stimulating hormone concentrations in pregnant and lactating beetal-cross and native goats in garmsar township. methods: one hundred beetal-cross (n=50) and native (n=50) does in 4 groups (25 pregnant beetal-cross, 25 lactating beetal-cross, 25 pregnant native and 25 lactating native) were used in this study. blood samples were obtained via jugular venipuncture and analyzed for serum t3, t4 and tsh concentrations. results: breed had a significant (p<0.05) effect on t4 concentration and pregnancy had a significant (p<0.05) effect on t3 and tsh concentrations. no significant differences were seen for serum t3, t4 and tsh concentrations between pregnant and lactating native does. however, in the pregnant beetal-cross, serum t3 and t4 concentrations were lower (p<0.05) and tsh concentration was higher (p<0.05) than lactating beetal-cross does. conclusions: the results of the present study highlight the relationships between thyroid activity and breed in the goat species that may play a role in more occurrence of congenital goiter in beetal-cross in garmsar township.