Based on 1068 observations of Sahiwal cattle for a period of 23 years (1980-2002)
maintained at National Dairy Research Institute, Kamal, the calving .interval was found to be
408.20±3.68 days with service period of 123.73±3.64 days, gestation period of 285.64±
0.44 days, lactation length of 254.25±3.79 days and dry period of 133.58±4.22 days based
on all lactations. The path analysis of calving interval by taking reproductive components revealed
that service period (99.5%) explained the maximum variability, whereas the effect of gestation
period was almost nil. .The total effect of service period was almost completely due to its direct
effect. By taking the productive components of calving interval, the dry period was found to
have more effect than lactation length. The total effects of dry period and lactation length were
28.78 and 13.68 per cent, respectively, for all lactations. Both the traits contributed mainly by
their direct effects.
