Oestrous cycle characteristics and blood progesterone levels in Holstein heifers under altitude and tropical conditions in Columbia
1994
Cardozo, J.A. | Hernandez, A. | Diaz, F.
Ten cycling heifers were studied during 11 months to determine the possible influence of some environmental parameters of a high altitude and tropical zone, on oestrous cycle and oestrous duration, hour of estrous presentation and blood progesterone levels. The climatic variables studied were rainfall, humidity, temperature and sunshine duration. Estrous cycle duration varied between 17 and 27 days with a mean value of 21.1. Estrous duration varied between 9 and 16 h, with a mean value of 10.64 h. The percent distribution of oestrus appearance at different times of a day, was as follows: 25 per cent occurred between 6 h et 18 h; 37.5 per cent between 6.30 and 10.00; 29.4 per cent between 10.30 and 16.00; and 8.1 per cent between 16.30 and 17.30. Progesterone levels in days 0 (oestrous), 5, 10, 15 and 20 of the oestrous cycle had mean values of 0.0, 1.27, 3.77, 4.80 and 0.32 ng per ml, respectively. Statistical analysis showed no effect of environmental parameters on the physiological variables and on the levels of the hormones analysed throughout the period studied. It seems that Holstein cattle adapt well to the climatic conditions of Bogota.
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