Lawson L G, Bruun J, Coelli T, Agger J F, Lund M
Department of Animal Science and Animal Health, The Royal Veterinary and Agricultural University, Copenhagen, Denmark.
J Dairy Sci. 2004 Jan;87(1):212-24. doi: 10.3168/jds.S0022-0302(04)73160-4.
Relationships of various reproductive disorders and milk production performance of Danish dairy farms were investigated. A stochastic frontier production function was estimated using data collected in 1998 from 514 Danish dairy farms. Measures of farm-level milk production efficiency relative to this production frontier were obtained, and relationships between milk production efficiency and the incidence risk of reproductive disorders were examined. There were moderate positive relationships between milk production efficiency and retained placenta, induction of estrus, uterine infections, ovarian cysts, and induction of birth. Inclusion of reproductive management variables showed that these moderate relationships disappeared, but directions of coefficients for almost all those variables remained the same. Dystocia showed a weak negative correlation with milk production efficiency. Farms that were mainly managed by young farmers had the highest average efficiency scores. The estimated milk losses due to inefficiency averaged 1142, 488, and 256 kg of energy-corrected milk per cow, respectively, for low-, medium-, and high-efficiency herds. It is concluded that the availability of younger cows, which enabled farmers to replace cows with reproductive disorders, contributed to high cow productivity in efficient farms. Thus, a high replacement rate more than compensates for the possible negative effect of reproductive disorders. The use of frontier production and efficiency/inefficiency functions to analyze herd data may enable dairy advisors to identify inefficient herds and to simulate the effect of alternative management procedures on the individual herd's efficiency.
对丹麦奶牛场各种繁殖障碍与产奶性能之间的关系进行了调查。利用1998年从514个丹麦奶牛场收集的数据估计了随机前沿生产函数。获得了相对于该生产前沿的农场层面产奶效率的度量，并研究了产奶效率与繁殖障碍发病风险之间的关系。产奶效率与胎衣不下、诱导发情、子宫感染、卵巢囊肿和引产之间存在中等程度的正相关关系。纳入繁殖管理变量后表明，这些中等程度的关系消失了，但几乎所有这些变量的系数方向保持不变。难产与产奶效率呈弱负相关。主要由年轻农民管理的农场平均效率得分最高。低、中、高效牛群中，因效率低下导致的估计牛奶损失分别平均为每头奶牛1142、488和256千克能量校正奶。得出的结论是，年轻奶牛的可得性使农民能够替换患有繁殖障碍的奶牛，这有助于高效农场的高产奶量。因此，高替换率足以弥补繁殖障碍可能带来的负面影响。使用前沿生产和效率/无效率函数来分析牛群数据，可能使奶牛顾问能够识别低效率牛群，并模拟替代管理程序对个体牛群效率的影响。
