Department of Animal Science and Dairy Science, Mahatma Phule Krishi Vidyapeeth, Rahuri - 413 722, India.
A data on 2040 records of halfbreds (FG and JG) and three breed (FJG, JFG and BFG) Gir crosses were collected and analysed by least-squares method. The genetic group, period and season of calving, parity, age and weight at first calving were considered as sources of variation. The overall least-squares means for calving interval of first five lactations and their pooled were 419.60±4.38, 401.89±7.02, 401.32±5.82, 400.62±8.16, 387.33±12.58 and 403.45±3.45 days, respectively. The calving interval of first five lactations were non-significantly affected by all the sources of variation except genetic group effect (P<0.05) on first calving interval. The genetic group, lactation order (P<0.05) and period of calving (P<0.01) had significant effect on the pooled calving interval.
