Physiology and Reproductive Responses of Crossing Beef Cow

Abstract

Crossbreeding beef cattle cause genetic changes related to its physiology and reproductive traits. This study was conducted to evaluate physiology and reproductive responses of crossing beef cows, that maintained in locations with different temperature and air humidity. Crossing between Peranakan Ongole cow with Simmental (SIMPO) or with Limousin (LIMPO) bull, each as 10 heads, kept in lowlands and highlands area. Parameters observed : environmental conditions, physiology and reproduction performances of cow. Data obtained are analysed by t-test and or presented descriptively. The results showed: daily air temperature that comfortable for cows at 4 pm until 8 am in lowland or at 4 pm until 10 am in highland, resulting in high respiration and pulse frequencies cows in lowland (28.7 and 86.3 times/minute); nutrient rations intake that less (especially in cows at lowlands), causing slow secretion pattern of progesterone and too fast secretion pattern of estrogen hormones, so achievement of its concentrations at before until after estrus were still high (minimal levels of progesterone from 3.2 to 5.2 ng/mL; maximum levels of estrogen from 27.8 to 35.3 pg/mL); abnormality patterns and levels of reproductive hormones secretion, is thought to be because declining reproduction performance of the crossing beef cows (estrous cycles 19 until 38 days; calving interval 427 until 479 days). Concluded, crossing beef cows are better be maintained in highlands than in lowlands.