Abstract：
Grain mixes varying in proportions of wheat grain, barley grain, canola meal, and corn grain were fed to grazing dairy cows in early lactation to determine the contribution of canola meal and corn grain to milk yield, BW, BCS, eating behavior, and blood serum metabolite concentrations. The experiment used 80 multiparous, seasonally calving Holstein-Friesian dairy cows during the first 100 d of lactation, the treatment period, and over the subsequent carryover period of 100 d, during which all cows were fed a common diet. Cows were divided into 4 cohorts (blocks) based on calving date and within each cohort, 5 cows were randomly allocated to each of the 4 treatments. Dietary treatments included disc-milled grain mixes comprising (on a DM basis) (1) a control treatment of wheat (25%) and barley (75%); (2) wheat (25%), barley (50%), and canola meal (25%); (3) wheat (25%), barley (50%), and corn (25%), and (4) wheat (25%), barley (25%), canola meal (25%), and corn (25%). Treatment diets were introduced at 19 DIM ± 4.7 d, which included a 7-d adaptation period and were applied up until 100 DIM. Each grain mix was fed at 9 kg of DM/cow per day, offered twice daily, in equal proportions in the parlor at milking times. In addition to the grain mix, all cows grazed perennial ryegrass pasture at a daily allowance of ∼35 kg of DM/cow per day (measured to ground level). Results were analyzed in terms of corn and canola presence or absence in the diet. Including canola meal in grain mixes increased grain intake and pasture intake by 0.6 and 2.1 kg of DM/cow per day, respectively, resulting in an increased milk yield of 2.6 kg/cow per day during the first 100 d of lactation. Including canola meal also increased yields of milk fat and protein, and concentrations of milk fat, as well as increasing mean BW and BCS over the 100 d. The inclusion of canola meal in the grain mixes also resulted in greater blood serum BHB and urea concentrations, compared with feeding grain mixes that did not contain canola meal. The inclusion of corn grain provided no milk production benefits and did not change BW, BCS, or any feeding behavior variables. There were no carryover effects on milk production from either canola meal or corn grain after the treatment period. In summary, the results demonstrate that the provision of canola meal in grain mixes can improve milk production and increase mean BCS. Further, there are no benefits to milk yield when a proportion of barley is substituted for corn, in a wheat and barley grain mix fed to grazing dairy cows in early lactation. However, these results are dependent on the level of inclusion and the feeding system employed.
摘要：
小麦籽粒比例不同的谷物混合物，大麦谷物,在泌乳早期将油菜粉和玉米粒饲喂给放牧的奶牛，以确定油菜粉和玉米粒对牛奶产量的贡献，体重(BW),身体状况评分（BCS），饮食行为和血清代谢物浓度。实验使用了80个多产，在泌乳的前100天，季节性产下荷斯坦-弗里斯奶牛，治疗期,在随后的100天的结转期内，在此期间，所有奶牛都被喂养一个共同的饮食。根据产牛日期和每个队列将奶牛分为4个队列（块），将5头牛随机分配到4种处理中的每一种中。饮食处理包括圆盘研磨的谷物混合物，包括（基于干物质（DM））1）小麦（25％）和大麦（75％）的对照处理；2）小麦（25％），大麦（50％）和油菜粉（25％）；3）小麦（25％），大麦(50%)和玉米(25%)，和4)小麦(25%)，大麦（25%），菜籽粉（25%），玉米（25%）。在19d的牛奶（DIM）±4.7d中引入治疗饮食，其中包括7d的适应期，并一直应用到100DIM。每种谷物混合物以每日9千克DM/牛饲喂，每天提供两次，挤奶时间在客厅里等比例。除了谷物混合物，所有母牛都在多年生黑麦草牧场上放牧，每天的摄入量约为每天35kgDM/母牛（测量至地面）。根据饮食中是否存在玉米和油菜来分析结果。包括谷物混合物中的油菜粉，使谷物摄入量和牧场摄入量每天增加0.6和2.1千克DM/牛，分别,在哺乳的前100天，每头牛每天的产奶量增加了2.6公斤。包括油菜粉也增加了牛奶脂肪和蛋白质的产量，和牛奶脂肪的浓度，以及在100d内增加平均BW和BCS。在谷物混合物中包含油菜粉也导致更高的血清β-羟基丁酸和尿素浓度，与不含油菜粉的谷物混合饲料相比。包含玉米粒没有提供牛奶生产的好处，也没有改变BW，BCS或任何喂食行为变量。在处理期后，无论是油菜籽粉还是玉米粒，对牛奶的产量都没有残留影响。总之,结果表明，在谷物混合物中提供油菜粉可以改善牛奶产量并增加平均BCS。Further,当一定比例的大麦代替玉米时，对牛奶产量没有好处，在早期哺乳期饲喂放牧奶牛的小麦和大麦谷物混合物中。然而,这些结果取决于夹杂物的水平和所采用的喂养系统。
