Peripheral Plasma FSH Concentration in Relation to Expression of Estrus in Sahiwal Cattle (bos indicus)

National Dairy Research Institute,

Karnal – 132 001

Abstract : An experiment was conducted to investigate the changes in peripheral plasma FSH concentrations in relation to expression of estrus in Sahiwal cows. Out of total five estrus, three were accompanied by overt signs whereas rest two were silent estrus. In cows with overt estrus, plasma FSH concentrations during periestrus, early luteal, midluteal and late luteal phase were 1.65 ± 0.34, 1.67 ± 0.21, 1.58 ± 0.18 and 1.69 ± 0.31 ng/ml, respectively and the corresponding values in cows with silent estrus being 0.68 ± 0.39, 0.50 ± 0.12, 0.75 ± 0.13 and 0.46 ± 0.12 ng/ml, respectively. The overall plasma FSH levels in cows that exhibited overt estrus was 1.63 ± 0.82 ng/ml as against 0.64 ± 0.55 ng/ml in silent estrus. It was concluded that FSH levels were higher (P<0.01) in cows that exhibited overt estrus compared to silent estrus.

Key words : FSH      expression of estrus       overt estrus      silent estrus       cattle