Department of Animal Science, Faculty of Agriculture. University of Tabriz, East Azerbaijan, Tabriz, Iran
Objective: The cows that don’t have access to sufficient energy in their ration can get sickness. Milk production has a high priority in metabolism of dairy cows so lactating cows are more prone to get sick This can ruin all the benefits of higher milk yield because of the higher prevalence of the disorders. Methods: Data for this research had gathered from a herd with 1600 Holstein cattle in East Azarbayjan province of Iran. Data were from 5052 lactation period of 1796 Holstein-Frisian cows which had parturition among 2005-2009. Seven groups of disorders have been analyzed. They are as follow: Cecal dilatation and rotation, diarrhea, abomasal distention and displacement to the right or left, locomotion problems and metritis. Each model consists of milk yield, parity, season and the year of calving. To determine the correlation between 305-day milk yield and occurring of disorders data have been analyzed with logistic regression model. Results: In this research current lactation was used as the lactation with occurrence of particular disorder. According to performed analysis on all cattle (heifers and the cows) higher milk yield was not a risk factor for the disorders occurrence except for diarrhea. Our outcomes showed a negative correlation between milk production with abomasal distention and left abomasal displacement. Analysis of correlation between prevalence of the disorders and 305- day yield showed a negative correlation with abomasal dilatation and displacement to the left and a positive correlation with diarrhea. Parity had a negative correlation with cecal rotation and dilatation, and a positive correlation with diarrhea. The year of calving had a significant correlation with abomasal dilatation and displacement of that to the right, cecal dilatation and rotation, diarrhea and locomotion problems. Calving season had only a significant relationship with cecal dilation and rotation. This research showed a complete correlation between some diseases and disorders in dairy cows and parameters that refer to milk production.