Annual pattern of plasma progesterone in normal cycling buffaloes ( Bubalus bubalis) fed two levels of nutrition

Abstract

The changes in plasma progesterone concentration were measured by a radioimmuno-assay technique in twelve non-lactating Murrah buffaloes for one year. These buffaloes were distributed into two groups of six each and were fed on a maintenance ration in group I and on a sub-maintenance ration in group II. Blood samples were collected from both groups of buffaloes on alternate days, beginning from day zero (day of oestrus) through the duration of complete oestrous cycles. The progestone level was low on the day of oestrus and increased progressively, showing a peak value between days 14 and 18 depending upon the oestrous cycle length. Five out of six buffaloes in group II and one from group I showed long anoestrous periods during the summer months. The progesterone concentration remained basal throughout the anoestrous periods in group II as a result of inactive ovaries. It was thus apparent that under-nutrition coupled with high environmental temperature stress was responsible for long anoestrous periods in buffaloes.