Department of Dairy Science, Virginia Polytechnic Institute and State University, Blacksburg 24061, USA.
J Dairy Sci. 2011 Jan;94(1):507-11. doi: 10.3168/jds.2010-3433.
First-lactation Holstein (HH), Jersey (JJ), and crossbred cows (HJ and JH, with sire breed listed first, followed by dam breed) were observed for cumulative energy intake (CEI15) and energy used for milk production (CEL15) at wk 15 of lactation in addition to recordings of health problems and pregnancy. Cumulative energy balance (CEB15) was calculated from CEI15 and estimates of expenditures at wk 15 of lactation. Feed efficiency (FE15) was calculated by dividing CEL15 by CEI15. Data included 140 cows with 43, 34, 41, and 22 in the HH, HJ, JH, and JJ groups, respectively. The first incidence of displaced abomasum (DA), ketosis (KET), mastitis (MAST), and metritis (MET) was recorded in the first 100 d of lactation with an incidence of the disease coded as 1 and no incidence coded as 0. Pregnancy (PREG) at d 150 was recorded as 1 if a cow had conceived by d 150 and 0 if she had not. Logistic regression was used to analyze health and fertility with fixed effects in the model including genetic group, linear and quadratic effects for age at calving, and year-season of freshening group. Pregnancy was analyzed with the same variables and the addition of CEB15. In other analyses, CEB15, CEI15, CEL15, and FE15 were response variables with the same explanatory variables plus health events (MAST, DA, MET, and KET), where each health event was a separate analysis. Genetic group effects were significant in the occurrence of MAST and a trend for MET, but were not significant for PREG, DA, and KET. Significant odds ratio for MAST was 19.6 for HJ cows when compared with that for HH cows. Thus, HJ cows were 19.6 times more likely than HH cows to have an incidence of MAST. The trend was for HJ and JH to have a lower odds ratio of MET than that of HH. No other genetic group effects were significant in any of the disease and PREG models. The linear and quadratic terms for age at calving were not significant. An occurrence of MAST decreased FE15 by 5.2±2.2%. Mastitis also decreased CEI15 and CEL15, but the compensatory reductions left the CEB15 unaffected. An occurrence of a DA decreased CEI15 and an incidence of KET decreased CEB15.
在泌乳第 15 周，对首次泌乳的荷斯坦牛（HH）、泽西牛（JJ）和杂交奶牛（HJ 和 JH，以父本品种为第一，母本品种为第二）进行了累计能量摄入（CEI15）和产奶能量利用（CEL15）的观测，同时还记录了健康问题和妊娠情况。在泌乳第 15 周时，通过 CEI15 和支出的估计值计算出累计能量平衡（CEB15）。FE15 通过 CEL15 除以 CEI15 计算得出。数据包括 140 头奶牛，分别在 HH、HJ、JH 和 JJ 组中，有 43、34、41 和 22 头奶牛。首次记录到瘤胃移位（DA）、酮病（KET）、乳腺炎（MAST）和子宫炎（MET）的发病时间是在泌乳的前 100 天，疾病的发病率编码为 1，无发病率编码为 0。如果奶牛在第 150 天已经受孕，则妊娠（PREG）记录为 1，否则记录为 0。使用逻辑回归分析健康和生育情况，模型中的固定效应包括遗传组、产犊时年龄的线性和二次效应，以及泌乳季节组。怀孕情况采用相同的变量进行分析，并增加了 CEB15。在其他分析中，CEB15、CEI15、CEL15 和 FE15 是因变量，具有相同的解释变量，加上健康事件（MAST、DA、MET 和 KET），其中每个健康事件都是一个单独的分析。遗传组对 MAST 的发生有显著影响，对 MET 有趋势，但对 PREG、DA 和 KET 没有显著影响。与 HH 奶牛相比，HJ 奶牛发生 MAST 的优势比为 19.6。因此，HJ 奶牛发生 MAST 的可能性是 HH 奶牛的 19.6 倍。HJ 和 JH 发生 MET 的可能性低于 HH 的趋势。在任何疾病和 PREG 模型中，其他遗传组的影响都不显著。产犊时年龄的线性和二次项都不显著。乳腺炎的发生使 FE15 降低了 5.2±2.2%。乳腺炎也降低了 CEI15 和 CEL15，但补偿性减少使 CEB15 不受影响。DA 的发生降低了 CEI15，KET 的发生降低了 CEB15。
