Arunvipas Pipat, VanLeeuwen John A, Dohoo Ian R, Keefe Greg P, Burton Shelley A, Lissemore Kerry D
Department of Large Animals and Wildlife Clinical Science, Faculty of Veterinary Medicine, Kasetsart University, Kamphaengsaen, Thailand.
Can J Vet Res. 2008 Oct;72(5):449-53.
Our study objective was to determine the ability of milk urea-nitrogen concentrations ([MUN]) to predict fecal nitrogen concentrations ([Fecal N]) in commercial dairy herds. A total of 83 dairy herds were each visited 3 times within 48 h after a monthly herd milk test. For each farm visit, forages were sampled for nutrient analyses, which were entered into a computerized ration evaluator, and fecal samples were taken per rectum from each of 6 cows (2 early-, 2 mid-, and 2 late-lactation). Fecal samples were pooled, mixed, and analyzed for nitrogen content. Fecal nitrogen concentrations were compared with the routinely measured nutritional parameters from the ration evaluation, and the herd average [MUN] for the previous milk test date using mixed linear regression analyses. Total protein supplied in the ration was significantly positively associated with [Fecal N], but herd average [MUN] was not associated (P > 0.10) with [Fecal N].
我们的研究目的是确定乳尿素氮浓度（[MUN]）预测商业化奶牛场粪便氮浓度（[粪便N]）的能力。在每月进行一次牛群牛奶检测后的48小时内，共对83个奶牛场各进行了3次走访。每次农场走访时，采集饲料样本进行养分分析，并将分析结果输入计算机化的日粮评估器，同时从6头奶牛（2头泌乳早期、2头泌乳中期和2头泌乳后期）的直肠中分别采集粪便样本。将粪便样本合并、混合并分析其氮含量。使用混合线性回归分析，将粪便氮浓度与日粮评估中常规测量的营养参数以及前一次牛奶检测日期的牛群平均[MUN]进行比较。日粮中提供的总蛋白与[粪便N]显著正相关，但牛群平均[MUN]与[粪便N]无关联（P>0.10）。
