Institute of Nutritional Physiology "Oskar Kellner," Leibniz Institute for Farm Animal Biology (FBN), 18196 Dummerstorf, Germany.
Institute of Reproductive Physiology, Leibniz Institute for Farm Animal Biology (FBN), 18196 Dummerstorf, Germany; Institute of Behavioural Physiology, Leibniz Institute for Farm Animal Biology (FBN), 18196 Dummerstorf, Germany.
J Dairy Sci. 2020 Jul;103(7):6054-6069. doi: 10.3168/jds.2019-17875. Epub 2020 May 14.
A growing need exists for the development of practical feeding strategies to mitigate methane (CH) emissions from cattle. Therefore, the objective of this study was to evaluate the influence of milk replacer feeding intensity (MFI) in calves on CH emission, rumen development, and performance. Twenty-eight female newborn Holstein calves were randomly assigned to 2 feeding groups, offered daily either 10% of the body weight (BW) in colostrum and subsequently 10% of the BW in milk replacer (MR; 10%-MR), or 12% of the BW in colostrum followed by 20% of the BW in MR (20%-MR). In wk 3, half of each feeding group was equipped with a permanent rumen cannula. Both groups were weaned at the end of wk 12. Hay and calf starter (mixture of pelleted grains) were offered from d 1 until wk 14 and 16, respectively. A total mixed ration was offered from wk 11 onward. Feed intake was measured daily and BW, anatomical measures, and rumen size weekly. Methane production and gastrointestinal passage rate were measured pre-weaning in wk 6 and 9 and post-weaning in wk 14 and 22, with additional estimation of organic matter digestibility. Rumen fluid, collected in wk 1, 2, 3, 6, 9, 14, 18, and 22, was analyzed for volatile fatty acid concentrations. Although the experimental period ended in wk 23, rumen volume of 17 calves was determined after slaughter in wk 34. Data was analyzed using ANOVA for the effects of feeding group, cannulation, and time, if applicable. Dry matter intake (DMI) of solid feed (SF) in 20%-MR animals was lower pre-weaning in wk 6 to 10 but mostly higher post-weaning. From wk 6 onward, anatomical measures and BW were greater in 20%-MR animals, and only the differences in body condition score gradually ceased post-weaning. Following the amount of SF intake, 10%-MR calves emitted more CH pre-weaning in wk 9, whereas post-weaning the 20%-MR group tended to have higher levels. Methane emission intensity (CH/BW) was lower pre-weaning in 20%-MR animals but was comparable to the 10%-MR group post-weaning. Methane yield (CH/DMI of SF) and estimated post-weaning organic matter digestibility were not affected by MFI. Rumen size normalized to heart girth was greater in 10%-MR calves from wk 5 to 10, but differences did not persist thereafter. In wk 34, rumen volume was higher in 20%-MR calves, but normalization to BW revealed no difference between feeding groups. In conclusion, high MFI reduces CH emission from calves pre-weaning, although this effect ceases post-weaning.
越来越需要制定实用的饲养策略来减轻牛的甲烷（CH）排放。因此，本研究的目的是评估犊牛代乳料喂养强度（MFI）对 CH 排放、瘤胃发育和性能的影响。28 头雌性新生荷斯坦犊牛被随机分配到 2 个喂养组，每天分别提供 10%的体重（BW）初乳，随后提供 10%的 BW 代乳料（10%-MR）或 12%的 BW 初乳，随后提供 20%的 BW 代乳料（20%-MR）。在第 3 周，每组的一半都配备了永久性瘤胃套管。两组均在第 12 周末断奶。干草和犊牛饲料（颗粒状混合物）从第 1 天提供至第 14 天，从第 16 天开始提供小牛饲料。从第 11 周开始提供全混合日粮。每天测量饲料摄入量，每周测量 BW、解剖学指标和瘤胃大小。在第 6 周和第 9 周的断奶前以及第 14 周和第 22 周的断奶后测量 CH 产量和胃肠道通过速度，并额外估计有机物消化率。在第 1、2、3、6、9、14、18 和 22 周收集瘤胃液，分析挥发性脂肪酸浓度。尽管实验期在第 23 周结束，但在第 34 周屠宰后仍测定了 17 头犊牛的瘤胃体积。如果适用，使用 ANOVA 分析喂养组、套管和时间的影响。20%-MR 动物的固体饲料（SF）干物质摄入量（DMI）在断奶前的第 6 至 10 周较低，但断奶后的大部分时间都较高。从第 6 周开始，20%-MR 动物的解剖学指标和 BW 较大，只有体况评分的差异在断奶后逐渐停止。根据 SF 摄入量的多少，10%-MR 犊牛在第 9 周断奶前排放更多的 CH，而断奶后 20%-MR 组的 CH 水平往往较高。断奶前 20%-MR 动物的 CH 排放强度（CH/BW）较低，但断奶后与 10%-MR 组相当。甲烷产量（SF 的 CH/DMI）和估计的断奶后有机物消化率不受 MFI 的影响。从第 5 周到第 10 周，10%-MR 犊牛瘤胃大小与心脏周长的比值较大，但此后差异不再持续。在第 34 周，20%-MR 犊牛的瘤胃体积较高，但与 BW 相比，两组之间没有差异。总之，高 MFI 可减少犊牛断奶前的 CH 排放，但这种影响在断奶后消失。
