DAIRY COW LONGEVITY IN VOLUNTARY MILKING SYSTEM
The increase of dairy production leads to the higher demand for the automation of some processes in farms. The large benefits for farmers usually does not give the same results for cow welfare and leaves significant mark on the cow potential lifespan. The aim of our study was to determine until what extent different factors affect the longevity traits of cows in voluntary milking system. In study were included 114 dairy cows that were included in voluntary milking system (VMS) group from year 2013 to 2018. The data about cows were collected from Latvian “Agriculture Data Center”. Cows were distributed in the 3 – 4 different groups depending on their milk productivity, milk quality, udder depth linear evaluation score and stature in the first lactation. The average lifespan of analyzed cows were 1824.252.05, when were obtained 30317.9±1280.25 kg milk that leads to 16.1±0.35 kg milk per one life day. Analysis of factors showed tendency that the significantly (p<0.05) longest lifespan and the lowest lifetime milk productivity were observed in group with lowest productivity in the first lactation (accordingly 2257.2±196.10 days with 37414.7±4499.70 kg milk). The somatic cell count (SCC) in milk showed similar tendency that highest longevity trait values were obtained in groups with the lowest SCC (accordingly 34170.7±2991.62 kg and 17.1±0.85 kg milk). The type trait analysis showed the tendency to decrease with the increase of type trait score. In the udder depth group the longest lifespan (2014.2±240.48 days) were observed form cows with udder depth evaluation score <5 points.