Factors Affecting Body Condition Score and Its Relationship with Productive and Reproductive Performances of Holstein Cows

The objective of the present study was to determine factors affecting body condition score (BCS) and its association with productive and reproductive performances in Holstein cows. Mixed model analysis was performed on monthly records of BCS from April 2006 to July 2012 comprising 34666 records from 3134 dairy cows in a large commercial dairy herd under arid climatic conditions of Isfahan in Iran. Body condition scores were recorded on a scale of 1 to 5. Fixed factors included in the final mixed model of analysis were evaluation year, parity and evaluation season and also year by parity, season by parity and year by season interaction effects. Average BCS in the dairy herd was 3.06 +/- 0.77. The results showed that there was an increasing trend for BCS over the years from 2006 to 2012 (P<0.001). Also, the recording season of winter provided greater BCS than other seasons (P<0.001). Mean BCS increased from first to third parity but then declined thereafter (P<0.05). The correlation between BCS and milk yield was negative and varied from -0.23 to -0.13 over the parities. The correlation between BCS and fat percentage was low and changed from 0 (fourth and greater parities) to 0.08 (first and second parities). There were low to medium correlations (0.14 to 0.29) between BCS and protein percentage over the parities. The correlation estimates between BCS and days open, calving interval and number of inseminations per conception were low and positive, but the correlation between BCS and conception rate was negative over the parities.