Abstract
This study was planned to explore the reproductive profile of the imported and farm-born Holsteins covering the
parameters like age at first service (AFS), age at first calving (AFC), service period (SP), gestation period (GP),
calving interval (CI) and dry period (DP) kept under the local conditions of Balochistan province of Pakistan. Effect
of locations of dairy farms on various reproductive parameters was also explored. Overall average values for AFS
were 315 to 986 d with an average of 660.42±12.42, AFC 604 to 1299 d with an average of 944.08±12.71, GP
275 to 299 d with an average of 280.62±0.25, SP ranged from 29 to 886 d with an average of 240±9.61 , CI
ranged from 301 to 922 d with an average of 451.1 0±5.55 and DP averaged as 59.15±20.61 d. The effect of year
of calving, season of calving, age of the dam, sex of the calf, type of birth, calving number and location of the farm
were studied and the results revealed that the year affected the AFS, AFC and SP (P<0.01); GP (P<0.05) but not
the CI. No effect of season on AFS, AFC, SP and CI (P>0.05) was observed except GP (P<0.05). The age of the
dam affected the AFC, GP and SP (P<0.05) but not the CI. No effect of sex of the calves, type of birth and calving
number on GP (P>0.05) was observed. Location of the farm did exert effect on AFS, AFC (P<0.01), CI (P<0.05)
but not on GP and SP (P>0.05).
