Tuyển tập các báo cáo nghiên cứu khoa học quốc tế về bệnh thú y đề tài: Modulatory effects of chitosan adipate on the T and B lymphocyte subsets in mice | J. Vet. Set. 2006 7 2 161-166 JOURNAL OF Veterinary Science Advancing parity is associated with high milk production at the cost of body condition and increased periparturient disorders in dairy herds Ji-Yeon Lee Ill-Hwa Kim College of Veterinary Medicine Chungbuk National University Cheongju 361-763 Korea The objectives of this study were to determine the effects of parity on milk production body condition change periparturient health and culling in Korean dairy herds. The data utilized included milk yield body condition score cow parity calving condition periparturient disorders culling and reproductive status which were recorded from 1290 calvings in eight dairy herds. The mean milk yield in cows over 305 days increased with increasing parity Ip . Cows with parities of 3 4 and 5 or higher lost more body condition than those with a parity of 1 during month 1 of lactation p and body condition recovery by cows with parities of 4 and 5 or higher was slower p than recovery by cows with parities of 1 2 or 3 until month 3 of lactation. The risk of retained placenta metabolic disorder and endometritis also increased with advancing parity p . Moreover the incidence of ovarian cysts was lower in cows with a parity of one than in cows with greater parities p . Culling rate due to reproductive failure also increased with advancing parity p . These results suggest that parity increases milk yield body condition loss during early lactation the risk of periparturient disorders and culling due to reproductive failure in dairy herds. Key words body condition culling milk yield parity perit-parturient disorder Introduction Milk is the major source of income generated on dairy farms and over the past several decades milk production by dairy cows has increased markedly. However this improvement comes at the cost of higher incidences of reproductive health problems and reduced fertility 21 Large energy requfrements at the onset of lactation in high- .
