The data on 575 records of 270 Holstein Friesian and 818 records of 326 Jersey cows maintained in Punjab,
Pakistan were analyzed. The cows were grouped into imported Holstein Friesian, imported Jersey, Farm born
Holstein Friesian and farm born Jersey cows. Breed group significantly influenced age at first calving, service
period and breeding efficiency. While non-significant effect of season of birth was observed on these traits except
service period. Effect of lactation number was non-significant service period. The longest age at first calving was
observed in cows born during summer season in farm born Holstein Friesian and Jersey cows. Service period of
imported Holstein Friesian and Jersey cows was higher than those of farm born Holstein Friesian and Jersey
cows. Shortest service period was observed in summer calvers in imported Holstein Friesian and farm born
Jersey cows while among imported Jersey and farm born Holstein Friesian cows shortest service period was
observed in autumn calvers. Breeding efficiency in Jersey cows was significantly higher than Holstein Friesian
cows. Maximum breeding efficiency was observed in farm born (during summer and winter season) Holstein
Friesian and Jersey cows.
M. Lateef, K.Z. Gondal, M. Younas, M.1. Mustafa, M.K. Bashir. (2008) Reproductive performance of Holstein Friesian and Jersey cattle in Punjab, Pakistan, , Volume-45, Issue-2.
