The data on 1742 reproduction records belonging to 447 Friesian X Sahiwal crossbreds maintained at Southern military dairy farms were analysed to study the effect of genetic grade, period, farm and age at first calving interval. Effect of inheritance level and age at first calving on service period and calving period was non­significant. Both traits were influenced significantly by farm effect. Calving interval was affected by period significantly. The heritability estimated did not differ from zero. The results indicated that improvement in the management practices and nutrition in the herd would help in shortening the service period and calving interval