Department of Ruminant Production, Institut de Recerca i Tecnologia Agroalimentàries (IRTA), 08140 Caldes de Montbui, Spain.
J Dairy Sci. 2013 Aug;96(8):5226-36. doi: 10.3168/jds.2012-6419. Epub 2013 May 22.
Fifteen Holstein male calves were randomly assigned to 1 of 3 dietary treatments according to age and body weight (BW) to determine the effects of feeding different forages sources on rumen fermentation and gastrointestinal tract (GIT) development. Treatments consisted of a starter (20% crude protein, 21% neutral detergent fiber) fed alone (CON) or supplemented with alfalfa (AH) or with oat hay (OH). All calves received 2L of milk replacer (MR) at 12.5% dry matter twice daily until 49 d of age. Calves received 2L of the same MR from 50 to 56 d of age and were weaned at 57 d of age. Individual starter, forage, and MR intakes were recorded daily and BW was recorded weekly. A rumen sample was taken weekly to determine rumen pH and volatile fatty acid concentrations. Three weeks after weaning, animals were harvested and each anatomical part of the GIT was separated and weighed with and without contents. Rumen pH was lower in CON than in OH and AH calves. Furthermore, acetate proportion in the rumen liquid tended to be greater in AH than in CON and OH treatments. Total GIT weight, expressed as a percentage of BW, tended to be greater in AH compared with the other 2 treatments. Rumen tissue tended to weigh more in CON than in OH animals. Animals with access to forage tended to have a greater expression of monocarboxylate transporter 1 than CON calves. In conclusion, calves supplemented with oat hay have a better rumen environment than calves offered no forage and do not have an increased gut fill.
15 头荷斯坦公犊牛按照年龄和体重（BW）随机分为 3 种日粮处理组，以确定饲喂不同饲草来源对瘤胃发酵和胃肠道（GIT）发育的影响。处理组由单独的开食料（CON）或添加苜蓿（AH）或燕麦干草（OH）组成。所有犊牛在 49 日龄前每天接受 2L 干物质含量为 12.5%的代乳料（MR），2 次/d。50-56 日龄时，犊牛每天接受 2L 相同的 MR，并于 57 日龄断奶。每天记录犊牛的开食料、饲草和 MR 采食量，每周记录 BW。每周从瘤胃中采集 1 个样本，以确定瘤胃 pH 值和挥发性脂肪酸浓度。断奶后 3 周，对动物进行屠宰，分离并称重每个 GIT 解剖部位，包括内容物和不包括内容物。CON 组犊牛的瘤胃 pH 值低于 OH 和 AH 组。此外，AH 组的乙酸比例倾向于高于 CON 和 OH 组。以 BW 的百分比表示，总 GIT 重量在 AH 组中趋于大于其他 2 个处理组。CON 组的瘤胃组织重量倾向于大于 OH 组。采食饲草的动物比 CON 组的单羧酸转运蛋白 1 表达更高。总之，与不提供饲草的犊牛相比，饲喂燕麦干草的犊牛具有更好的瘤胃环境，并且不会增加肠道充盈度。
