نوع مقاله : فیزیولوژی (جانوری)
نویسندگان
گروه علوم دامی، دانشکده کشاورزی، دانشگاه جیرفت. جیرفت. ایران
چکیده
کلیدواژهها
عنوان مقاله [English]
نویسندگان [English]
Culling of dairy cows causes financial losses and a higher cost of replacing the culled cows, therefore quantification of the association between risk factors and culling is useful for Reduce costs and increase profitability. The present study was conducted to evaluate the association between productive and reproductive risk factors which may affect culling of the dairy cows. The data were collected from2003 to 2012.The Logistic regression model was applied to investigate the associations between the response variable, the risk of culling, and predictor variables including parity, calving ease, standardized 305-d milk yield, age at the first calving, calving interval, day to first and last service and numbers of inseminations per conception. The risk of culling increased (P< 0.001) with parity. The odds ratio (OR) increased with increasing in calving difficulty score except for the farmer- assisted cows. Risk of culling (P< 0.001) decreased with increases in the standardized 305d milk yield. Cows that calved first at about 24 months of age had a lower risk of culling. The ORs were 1.28, 1.67 and 2.21 for cows with 349 to 385, 385 to 442 and ≥442 (d) calving intervals, and the risk of culling was increased with increases in the day to last service and insemination but days to first service had no significant effects on culling of dairy cow. Results showed that the studied risk factors significantly affected the culling rate in cows, and can be used as management tools for decreasing the risk of culling and increasing the profitability of the enterprise.
کلیدواژهها [English]
)