AN ANALYSIS OF THE FACTORS AFFECTING BIRTH WEIGHT AND ACTUAL MILK YIELD IN SWEDISH RED CATTLE USING REGRESSION TREE ANALYSIS

Abstract

Performance records (birth weight and actual milk yield) on 206 Swedish Red cattle maintained at private organic diary cattle enterprise in Kelkit district of Gumushane province, in Turkey, were analyzed through regression tree method to determine the effects of some factors affecting birth weight and actual milk yield. The birth weight of calves averaged as 41.034 +/- 4.218 kg. Out of total calves born, twin born calves were 2.9 %. Single born calves were heavier (41.185 +/- 3.840 kg) than twin born (36.000 +/- 10.545 kg). The results revealed that the most significant variable affecting birth weight was birth type, followed by birth season, sex and body condition score (BCS2) of the dam during birth. Lactation period and peak milk yield were important variables affecting the actual milk yield in the dairy herd under investigation.