RELATIONSHIP OF BLOOD METABOLITES WITH REPRODUCTIVE CYCLICITY IN INDIGENOUS AND EXOTIC BREEDS OF DAIRY COWS UNDER TROPICAL CONDITIONS

The improved genetic status alters metabolic priorities of the body compromising fertility. 10 Holstein Friesian (HF), 10 Jersey, 10 Achai and 10 F1 cows were selected at Peshawar and monitored for 5 months. 65% cows reestablished estrus while 35% remained anestrous. 80% HF and 70% Jersey showed estrus. In Achai only 40 % were cyclic. Blood glucose and daily milk yield (DMY) significantly affected post partum estrus (P<0.01) while blood protein and triglycerides did not affect it. The blood glucose levels were lower (39.93 ± 3.14 mg/dl) two months before and increased (49.63 ± 2.47 mg/dl) towards estrus commencement and then declined. Anoestrus cows were deficient in blood glucose (35.74 ± 1.57 mg/dl). The anestrous cows were deficient in blood glucose concentrations. Higher blood glucose and total protein supported reproductive cyclicity in Jersey while higher triglycerides in Achai lowered fertility. In crossbred cows, the rising levels during pre estrus period indicated greater adaptability to the local environment. It is suggested that overfeeding has an adverse effect on milk yield in the low yielding Watani (local) cows poor genetic potential to utilize the extra amount of concentrates for milk synthesis; hence the feed may be utilized for crossbred cows. The north zone showed the best efficiency producing 8 kg day-1 milk while consuming 2.3kg concentrates which may be attributed to the well developed irrigation system supporting production of plenty of fodder. Watani as well as the crossbred dairy cows showed good estrus symptoms for breeding. Blood glucose decreased on 17th day of estrus cycle probably due to its utilization for supporting estrus activities. LH reached the highest level on day 17th probably which may be sufficient for supporting ovulation. Keywords: Blood metabolites, reproduction, cyclicity, breeds, environment