Reproductive performance of Nili-ravi buffaloes

Around 800 reproduction records of Nili-Ravi buffaloes maintained at a Government Dairy Farm from 1988 through 1996 were studied. Mean age at first successful breeding and age at first calving were 908 plus minus 9 days and 1215 plus minus 9 days, respectively. Season and year of birth had no effect on age at first calving, whereas, season of birth had a significant (P less than 0.01) effect on puberty age. Puberty and age at first calving was longer (987 plus minus 59 and 1281 plus minus 68 days, respectively) in buffaloes born during dry summer and shorter (863 plus minus 92 days and 1170 plus minus 92 days; respectively) in spring births. Average length of calving interval was 528 plus minus 9 days. Season and year of calving affected (P less than 0.05) length of calving interval, irrespective of lactation number. Animals calved in winter had 114 days longer (P less than 0.01) first calving interval on the average than those calved in fall. Considering all lactations, fall calvers had 98 days longer (P less than 0.01) calving interval on the average than those calved in winter. Spring calvers had 79 days shorter (P less than 0.02) calving interval on the average than buffaloes calved in fall. Mean first dry period was 306 plus minus 15 days in first calvers and 235 plus minus 8 days in other buffaloes. Season, and year of calving and lactation number had a significant effect on length of dry period in Nili-Ravi buffaloes in first (P less than 0. 01) and all lactations (P less than 0.001). Considering first lactation, buffaloes calved in winter had longer (P less than 0.02) dry period by 92 days than those calved in fall. Winter first calvers also had longer (P less than 0.02) dry period than buffaloes calved in spring. Winter calvers on the average had 129 days longer (P less than 0.02) dry periods than spring calvers. Length of first dry period in spring calvers was also 116 days shorter (P less than 0.05) than buffaloes calved in dry summer. The remaining contrasts with respect to first lactation were non significant. Based on first lactation records, buffaloes calved in 1989 had shorter (P less than 0.05) dry period than those calved in 1992 and 1993. First dry period of buffaloes was longer (P less than 0.01) than the second through 5th. The remaining differences were non significant. Season of calving had no effect on birth weight. However, calves dropped in spring were somewhat heavier than calves born in other seasons. It was concluded that reproduction management of buffaloes should be improved to curtail length of calving interval.