Reproductive performance of crossbred heifers

Abstract

A detailed Investigation was undertaken with the object of studying the reproductive performance of crossbred heifers including the pattern of oestrous cycle. Data of 152 crossbred heifers and personal observation of 50 crossbred heifers belonging to the Cattle breeding farm, Thuraboormuzhi formed the materials for the study. The observations made and inferences drawn are furnished below. The lowest birth weight was Observed In 62.5 per cent Jersey crosses and highest in 50 per cent Holstein crosses* Attainment of puberty was earliest in 62.5 percent Jersey crosses while this was latest in 50 per cent brown Swiss crosses. Minimum weight at puberty and weight at conception were noticed in 62.5 per cent Jersey crosses whereas the corresponding values were maximum in 50 per cent Holstein crosses. Similarly age at conception was lowest in 62.5 per cent Jersey crosses and highest in 50 per cent brown swiss. Number of inseminations were conception was highest in 62.5 per cent jersey crosses and lowest in 75 per cent Brown Swiss crosses. Birth weight had significant positive correlation with weight at puberty and weight at conception in 50 per cent Jersey crosses whereas in 62.5 per cent the birth weight was significantly correlated

only to weight at conception The overall mean length of oestrous cycle was found to be 19.54 days in the crossbreds studied* Significant difference was noticed in the length of oeetrous cycles in different genetic groups* The mean duration of oestrus in the crossbreds studied was found to be 16.97 hours without any significant difference between the different genetic groups. Majority of crossbreds exhibited pronounced heat symptoms and none of them shewed weak signs of heat* Ovulation occurred between 8 and 20 hours after the end of oestrus in majority of cases* Jersey crossbreds did not exhibit an ovulatory heat* while brown swiss crosses exhibited a higher incidence of an ovulation*Metoestorous bleeding was absent in 50 per cent Jersey crossbreds while 50 per cent Holstein crossbreds exhibited a higher percentage.