Interactions between milk yield, milk urea nitrogen, body condition score and reproductive performance of dairy cows under farm condition

The present study was carried out to determine interaction between milk urea nitrogen and reproductive performance of dairy cows under farm condition. Ninety five primaparus dairy cows in a private farm were monitored for 32 weeks and milk samples collected weekly in first 10 weeks, biweekly after 10th week.Milk urea nitrogen level, open days and service per conception were 20.72±0.17mg/dL (minimum and maximum value; 15.91-26.17 mg/dL), 1.76 (1-6) and 88.35 days (38-223 days) respectively. No correlation was determined between milk ure nitrogen and service per conception(r=0.09, P>0.05) and open days (r=0.14, P>0.05). Significant negative correlation were determined between body condition score and milk urea-N (r=-0.24, P<0.02) , service per conception (r=-0.24, P<0.02), and service period (r=-0.30, P<0.01).The results showed that milk urea nitrogen level is not changed markedly in whole herd due to feeding similar and balanced diets. Furthermore primaparus cow had fewer problems in reproductive performance. The results revealed that factors decreasing body condition may interfere reproductive performance of dairy cows as well. Further studies should be carried out in different feeding condition shifting milk urea nitrogen level to observe relationship reproduction and milk urea nitrogen level.