Department of Animal Production, Faculty of Agriculture, Alexandria UniveNtii.),
Abstract
Records on University of Alexandria buffalo herd were collected du ing the period started In 1960 to study the effects of age and weight at first calvi g, first calving interval, first lactation milk yield, inbreeding, breeding efficiency, productive life, longevity and sire on calf crop per buffalo cow.
The results obtained were as follow:
1- Averages of calf crop per buffalo cow were 1.6. 1.5 and 2.0 for female. male and both sexes to:<;1 calves born during her lifespan.
2- Calf crop tended to decline significantly (P<O.01) as age at first calving increased and in contrast, it showed a tendency to increase significantly (P<O.05) ith the progress of weiaht at first calving.
3- Both first calving interval and first lactation milk yield had non Significant e ect on calf crop.
4- Calf crop was lower (1.5) for inbred buffaloes than that for non-inbred ones (2.1) and the difference was significant (P<O.05) in this respect.
s- Calf crop was affected significanliy (P<0.01) by each of breeding efficiency, productive life and longevity and it showed increasing trend.
6- Regression and correlation coefficients between calf crop and the mentioned factors came to the same results. Also, sex ratio and averages of birth eight of calves born were undertaken in the present study.
7- Differences in calf crop due to service sire effect were non Significant.