SOME FACTORS AFFECTING MILK YIELD AND LACTATION LENGTH IN NILI RAVI BUFFALOES

Effects of parity, lactation length, calving season, calf sex and service period on milk yield for 426 records in 134 Nili Ravi buffaloes maintained at the National Agricultural Research Center, Islamabad Pakistan during 1988-2004 were evaluted. The effects of parity, calving season, calf sex and service period were also recorded on lactation length of these buffaloes. The overall average milk yield was 1831.6 ± 530.9 litres per lactation and the average lactation length was 273.3 ± 52.8 days. Milk production was lower in first lactation than that in 2nd, 3rd and 4th lactations (P<0.05). Milk yield per lactation increased with increasing lactation length (P<0.05). The season of calving had significant effect on milk yield. Buffaloes calving in spring showed the highest and those calving in summer showed the lowest milk yield. Sex of calf did not affect milk yield. Milk yield of the animals conceiving within 31–100, 101–200 and 201–300 days after calving did not differ from one another. However, milk yield of the animals conceiving>300 days after calving (2045.6 ± 588.5 litres per lactation) was significantly higher than that of the animals conceiving within 31–100 days after calving (1846.1 ± 527.5 liters per lactation). The lactation length was not affected by parity, calving season, calf sex and service period. It is concluded that parity and lactation length significantly affected milk production in Nili Ravi buffalo, however, a service period of <300 days and calf sex did not affect the yield