Relationship among various production and reproduction Contributors of Breeding Efficiency in Dairy Buffaloes of Pakistan.

The performance of dairy buffaloes kept at three state farms were studied. A total of 5033 reproductive and productive records from the year 1985 through 2004 were utilized in the present study to investigate breeding efficiency (BE) and its various contributors in dairy buffaloes. General linear model, Pearson’s correlation and regression procedure were used to study the effect of herd, period, season of calving, birth weight (BW), age at puberty (AAP), lactation yield (LY) and calving interval (CI) on breeding efficiency. Average breeding efficiency of dairy buffaloes was 72.75 ± 10.58 %. Age at puberty, age at first calving (AFC) and calving interval being indicators of breeding efficiency averaged 951.09, 1339.29 and 558.36 days, respectively. The effect of year and season( different from results) of calving, lactation yield, calving interval, age at first calving and birth weight was found significant (P<0.001) on breeding efficiency, while the effect of herd was non significant. BE correlated positively with BW and LY and negatively with AAP, AFC and CI (r = 0.45, 0.30, -0.42, -0.49 and -0.07; P<0.001). Breeding efficiency increased with the increasing AFC up to 1400 days, remained high up to day 1500 and then decreased. An increase in lactation yield rapidly increased BE up to 1750 liters per lactation but further increase was associated with a sluggish upward trend in BE. Across the years the BE showed a persistent declining trend which was also associated with a declining BW and increasing AAP. The spring calvers showed the highest BE followed by winter, summer and autumn calvers. It may be concluded that birth weight was the most significant contributor of breeding efficiency in dairy buffaloes and it also influenced age at puberty, age at first calving and lactation yield.