Efectos ambientales que influyen en la dificultad de partos y el peso al nacimiento en la raza asturiana de los valles

Abstract

5928 records of Asturiana de los Valles beef cattle breed Control of Performance database were used to establish the main non-genetic effects influencing calving ease. Frequencies of dystocia recorded as recommended by the BIF Guidelines (1986) were 50.4 per cent for class 1 (no assistance), 39.6 per cent for class 2 (light assistance), 7.0 per cent for class 3 (hard assistance), 1.8 per cent for class 4 (caesarea), and 1.2 per cent for class 5 (abnormal presentation). Birth weight was the most important source of variation for dystocia. The threshold of birth weight for dystocic calving ranges between 41-42 kg in heifers, and 48-49 kg in multiparous cows. Male calves show 6.5 per cent more dystocic calving than female calves, and culard calves 16 per cent more than normal calves. Culard cows show 4 per cent more dystocic calving than normal cows. There is a significant interaction between the type of dam and the type of calf. Frequencies of dystocia are clearly higher in culard offspring of normal dams (+6.5 per cent) than in normal or intermediate offspring of culard dams.