Investigation of Reasons for Culling in Chungcheong Dairy Herds

Investigation of Reasons for Culling in Chungcheong Dairy Herds

This study was conducted to investigate reasons for culling of Chungcheong dairy herds and to investigate the relationships between cow parity, interval from calving to culling, or season and culling reasons. Lactation data from 826 cows on 9 dairy farms from 2013 to 2015, including reasons for culling, dates of birth, last calving, and culling, were analyzed. The overall culling rate was 29.8% (246/826), with mammary problems (23.2%) being the most prevalent reason for culling, followed by infertility (14.2%) and downer cow syndrome (11.0%). The culling rate varied among farms (18.8-43.1%, p < 0.05), but was greater in parity $4{\leq}(40.7%)$ than parities 1, 2, or 3 (17.9-23.6%), whereas the rate was less frequent during mid lactation (21.1%) than in early (36.2%) or late (42.7%) lactation. Moreover, the culling rate was greater during summer (35.8%) than other seasons (20.3-23.2%). Mammary problems, downer cow syndrome, and metabolic disorders were the more common reasons for culling during early lactation, whereas infertility was predominant during late lactation. Our data show that the culling rate in Chungcheong dairy herds was associated with cow parity, interval from calving to culling, and season, with the main reasons for the removal of cows from dairy herds being mammary problems, infertility, and downer cow syndrome.