THE EFFECT OF SELECTED FACTORS ON CHANGES IN BODY CONDITION IN HIGH-YIELD COWS

Abstract. An analysis was conducted of 644 body condition assessments made in 2011 in a herd of 52 Black-and-White Polish Holstein-Friesian cows with annual milk yield exceeding 10,000 kg. Body condition was assessed once a month according to the 5-point BCS system, accurate to within 0.25 points. Changes in body condition and the frequency of particular scores were found to be significantly influenced by lactation number (first or subsequent), the season in which calving took place, daily milk yield, milk urea level, and the period after calving. The highest average scores were noted in multiparous cows, in cows that calved in the summer, and in those with the lowest daily milk yield. The lowest scores were observed in cows with the highest milk urea level and in the period from the 5th to 7th month after calving. In addition, primiparous cows were found to begin lactation with lower fat reserves than multiparous cows, and had lower body condition scores in all periods after calving. Key words: body condition, cows, milk urea, milk yield, multiparous cows, primiparous cow