College of Animal Sciences, Haryana Agricultural University, Hissar–125 004 (India)
*Paper presented at I I Congress of SABRAO held from 22nd to 28th Feb., 73 at IARI, New Delhi.
Six hundred and seventy eight records of the interval between calving and conception after first lactation (first service period) of Indian buffaloes of military farms, progeny of 68 sires, were analysed by the method of fitting constants for the effects of farms, period, seasons, age and weight at calving. The average service period was 183⋅50 days with a coefficient of variability of 67 ⋅ 62% Farms, periods and age at first calving did not affect this trait significantly. Animals calving in the least calving season (January to June) had a longer service period than those calving in the most calving season. Heavier buffaloes at calving tended to have shorter service period.
Heritability of service period estimated from paternal half-sib correlation was 0⋅104±0⋅033. It can, therefore, be concluded that shortening of service period through mass selection may not be possible. Service period had significantly negative association with breeding and economic efficiencies indicating that shortening of service period may result in the improvement of both.
