THE EFFECT OF UDDER CONFORMATION TRAITS ON LATVIA NATIVE DAIRY COW MILK PRODUCTIVITY AND QUALITY

In Latvia there are 2 dairy cow breeds included in the national genetic resource program Latvian Brown (LBGR) and Latvian Blue (LZ). The aim of the study was to determine different udder conformation trait relationships with milk productivity and quality. The study analyzed 31 LBGR and 35 LZ breed cows. The analyzed cows were evaluated by their conformation traits, weighted and was estimated at least in 3 lactations. The information about cow productivity that was calculated in energy corrected milk (ECM), milk quality (somatic cell count) and different udder conformation traits was included in the data base. The data was obtained from the Latvia Agricultural Data Center. The highest milk productivity was obtained in the second lactation from LB breed cows - 6.731 kg ECM, but there was a slight decrease in the third lactation - 6.561 kg ECM. Less ECM was obtained from LZ breed cows; in the third lactation there was the highest amount of somatic cells - 271 thousand in 1 mL(-1) in milk. The first lactation cows were characterized by closer to optimal udder conformation trait results, but linear evaluation showed negative tendencies in the third lactation. The highest positive correlation with milk yield (r = 0.44) was obtained with udder rear height, but the highest negative correlation (r = -0.39) was obtained in the relationship with udder connection. The amount of somatic cells in relation to central ligament linear evaluation results showed a positive close correlation with coefficient (r = 0.40), but rear teat placement showed a negative correlation (r = -0.30).