Differences among cattle and farms as related to beef cow reproduction in the eastern plains of Colombia.

In the tropical savannas of Colombia, the Llanos Orientales, a field survey of 40 beef herds leased by farmers through a cooperative indicated that these herds had mean annual calving rates of 52 and 55 per cent in the Plains and Piedmont zones, respectively. Within zones, very large differences in reproductive rates were found between herds. The differences seemed to be associated with the soils and climates of the areas, condition and weight of cows and breed of cow. Only 9 to 13 per cent of nursing cows were found to be pregnant. Conception was seasonal, occurring mostly in the dry and early rainy seasons. Control of the time of weaning of calves, routine mineral supplementation and improved pasture management appeared to offer immediate possibilities for economically improving output of calves.