Aragona K M, Dennis T S, Suarez-Mena F X, Quigley J D, Hu W, Hill T M, Schlotterbeck R L
Nurture Research Center, Provimi, Cargill Animal Nutrition, Brookville, OH 45309.
Nurture Research Center, Provimi, Cargill Animal Nutrition, Brookville, OH 45309.
J Dairy Sci. 2021 Feb;104(2):1620-1629. doi: 10.3168/jds.2020-19487. Epub 2020 Dec 23.
A good transition from a mainly liquid diet to a solid diet of concentrates and forages is important considering the small size and development of the calf's rumen. However, the optimal amount of hay or other high-fiber ingredients in the diet of recently weaned calves is not well defined. The objective of this trial was to determine the effects of feeding 0, 5, or 10% chopped grass hay (6.5% crude protein, 64.6% neutral detergent fiber) with a textured, high-starch starter (20.5% crude protein, 38.4% starch, 14.1% neutral detergent fiber; protein pellet, whole corn, and oats) on performance and digestion in Holstein steer calves between 2 and 4 mo of age. Forty-eight calves (initial body weight = 90.7 ± 2.15 kg) were housed in group pens (4 per pen) and fed diets and water for ad libitum intake. Feed offered and refused was measured daily. Calf body weight, hip width, and body condition score (1-5 scale) were measured initially and at 28 and 56 d. Fecal samples were collected from the pen floor with care not to sample bedding material and composited by pen during d 5-9, 26-30, and 47-51 to estimate apparent total-tract digestibility using acid-insoluble ash. Data were analyzed as a completely randomized design with repeated measures and pen as the experimental unit. As grass hay increased, dry matter intake (kg/d) decreased linearly but tended to change quadratically. Dry matter intake as a % of body weight changed quadratically with increasing hay, increasing from 0 to 5%, and decreasing from 5 to 10% hay. Average daily gain (1.15, 1.12, and 0.95 kg/d), feed efficiency (0.336, 0.319, and 0.309 kg of average daily gain/kg of dry matter intake), and hip width change (4.6, 4.7, and 4.1) decreased linearly with 0, 5, and 10% hay, respectively. Overall estimates of dry matter, organic matter, neutral detergent fiber, acid detergent fiber, and crude protein digestibility changed quadratically with hay, increasing from 0 to 5%, and decreasing from 5 to 10% hay, whereas digestibility of starch, sugar, and fat decreased linearly with increasing hay. Digestibility of dry matter, organic matter, neutral detergent fiber, and acid detergent fiber increased from 2 to 3 mo of age, and decreased from 3 to 4 mo of age. Digestibility of starch decreased linearly and digestibility of fat and crude protein increased linearly with age. Digestive capacity did not appear mature by 4 mo of age. Feeding 5% chopped hay supported optimal digestion and growth in calves 2 to 4 mo of age, which agrees with previously published research.
考虑到犊牛瘤胃体积小且仍在发育，从主要的液体饲料顺利过渡到精料和草料的固体饲料十分重要。然而，刚断奶犊牛日粮中干草或其他高纤维成分的最佳添加量尚无明确界定。本试验的目的是测定给2至4月龄的荷斯坦阉牛犊饲喂0%、5%或10%的切碎禾本科干草（粗蛋白含量6.5%，中性洗涤纤维含量64.6%）与一种结构型高淀粉开食料（粗蛋白含量20.5%，淀粉含量38.4%，中性洗涤纤维含量14.1%；蛋白颗粒、整粒玉米和燕麦）对其生产性能和消化率的影响。48头犊牛（初始体重 = 90.7 ± 2.15千克）被饲养在群养栏舍（每栏4头）中，自由采食日粮和饮水。每天记录提供和剩余的饲料量。在试验开始时、第28天和第56天测量犊牛体重、臀宽和体况评分（1至5分制）。从栏舍地面采集粪便样本，注意不采集垫料，并在第5至9天、第26至30天和第47至51天按栏舍进行混合，以酸不溶性灰分估算表观全消化道消化率。数据采用完全随机设计并重复测量，以栏舍作为实验单位进行分析。随着禾本科干草添加量增加，干物质摄入量（千克/天）呈线性下降，但有二次曲线变化趋势。干物质摄入量占体重的百分比随干草添加量增加呈二次曲线变化，从0%干草增加到5%干草时上升，从5%干草增加到10%干草时下降。平均日增重（分别为1.15、1.12和0.95千克/天）、饲料效率（分别为0.336、0.319和0.309千克平均日增重/千克干物质摄入量）和臀宽变化（分别为4.6、4.7和4.1）分别随0%、5%和10%的干草添加量呈线性下降。干物质、有机物、中性洗涤纤维、酸性洗涤纤维和粗蛋白消化率的总体估计值随干草添加量呈二次曲线变化，从0%干草增加到5%干草时上升，从5%干草增加到10%干草时下降，而淀粉、糖和脂肪的消化率随干草添加量增加呈线性下降。干物质、有机物、中性洗涤纤维和酸性洗涤纤维的消化率在2至3月龄时上升，在3至4月龄时下降。淀粉消化率随年龄呈线性下降，脂肪和粗蛋白消化率随年龄呈线性上升。4月龄时消化能力似乎尚未成熟。饲喂5%切碎干草能支持2至4月龄犊牛的最佳消化和生长，这与先前发表的研究结果一致。
