REPRODUCTIVE CHARACTERISTICS OF GRAZING BIBOS BALI SUPPLEMENTED WITH CONCENTRATE

Abstract

The influence of concentrate during three estrous cycles and early pregnancy on
reproductive characteristics were evaluated. Twenty one calf-rearing cows were divided randomly into groups, group A (n=1l) were grazed on natural pasture as basal diet, whereas group B (n:l0) received an additional 2.4 kg of concentrate (1.2 kg cornmeal; 0.6 kg rice bran; 0.6 kg coconut cake). Animals from each group were closely obsen/ed for estrous characteristics, i.e. estrus detection two times a day by two experienced technicians. Blood samples taken from jugular vein were used for assessing plasma progesterone concentrations using RIA procedure. The mean length of the estrous cycle were determined to be 22.3 and 21.1 for cows grazing on natural pasture and cows receiving additional concentrate, respectively. Correspondingly, the length of estrus of the two groups was 18.7 and 20.8. Both groups exhibited good intensity of estrus, with scores 2.6 and 2.9 respectively showing no significant differences. Plasma progesterone concentrations during the estrous cycle were not influenced by concentrate supplementation. There was no significant difference in the progesterone levels of the two groups at the beginning of the luteal phase of the cycle which were 1.64 and 1.38 ng/mL for cows fed concentrate and not fed concentrate, respectively. Also, the mean concentration of progesterone at peak secretion on day 11 was similar for the two groups, i.e. 5.40 and 5.10 ng/mL for cows either offered concentrate or no concentrate. First-service conception rates were similar for both groups (60% vs 64%) of cows offered concentrate and not offered concentrate, respectively, whereas the pregnancy rates of the two groups (90% and 82%) were not affected by concentrate nor were the number of services per-conception (1.3 and 1.2).