Department of Agriculture, Nutrition, and Food Systems, University of New Hampshire, Durham, 03824.
Adisseo USA Inc., Alpharetta, GA.
J Dairy Sci. 2020 Nov;103(11):10207-10218. doi: 10.3168/jds.2020-18584. Epub 2020 Sep 18.
The objective of this study was to evaluate growth and performance of postweaning heifers supplemented with monensin (MON), sodium butyrate (SB), or the combination of MON and SB (MSB) compared with heifers not receiving these feed additives. Forty Holstein heifers [mean age 84.2 ± 1.2 d; body weight (BW) 99.8 ± 10.8 kg (mean ± SD)] were housed in a freestall barn, blocked by birth date, and randomly assigned to 1 of 4 treatments in a randomized complete block design. Treatments were (1) 100 g of soybean meal carrier (control; CON); (2) 0.75 g of SB/kg of BW + carrier (SB); (3) 1 mg of MON/kg of BW + carrier (MON); (4) 1 mg of MON/kg of BW + 0.75 g of SB/kg of BW (MSB). Data were analyzed using single degree of freedom contrasts evaluating CON versus additives (ADD), SB versus MON, and SB and MON versus MSB. Treatments were hand-mixed daily. Feed and orts were measured daily and frozen at -20°C. Orts samples were subsampled for dry matter (DM) determination, and total mixed ration samples were taken weekly and composited monthly for DM and nutrient analysis. Initial BW, heart and paunch girths, body length, blood samples, and fecal coccidia counts were measured before the start and weekly during the 12-wk trial. Blood samples were analyzed for glucose, plasma urea nitrogen (PUN), and ketone concentrations. Apparent total-tract nutrient digestibility was determined from d 21 to 27 and from d 63 to 69 using acid detergent insoluble ash as a marker. Daily dry matter intake (DMI) and metabolizable energy intake were increased in ADD compared with CON, and average BW, final BW, and heart girth tended to increase. Whereas MSB tended to be greater than SB and MON for heart girth, feed efficiency was greater with MON compared with SB. Compared with CON, ADD decreased coccidia counts. No effect of treatment on PUN was detected. Monensin and SB tended to have greater plasma glucose than MSB did. Average blood ketone concentrations were greater with ADD versus CON, in SB versus MON, and in MSB versus SB and MON. During the wk-3 digestibility phase, DMI tended to be greater in heifers fed SB versus MON, as well as in heifers fed MSB versus SB and MON. Digestibility of nutrients were similar, except that starch digestibility was increased in heifers fed MSB versus SB and MON. During the wk-9 digestibility phase, DMI and digestibility of nutrients were similar, except NDF, which tended to be greater in CON than in ADD. Overall, ADD resulted in positive growth and reduced coccidia compared with CON.
本研究的目的是评估在补饲莫能菌素（MON）、丁酸钠（SB）或 MON 和 SB 组合（MSB）的断奶后小母牛与未补饲这些饲料添加剂的小母牛相比的生长和性能。40 头荷斯坦小母牛[平均年龄 84.2±1.2 d；体重（BW）99.8±10.8 kg（均值±SD）]被安置在一个自由式畜栏中，按出生日期分组，并以随机完全区组设计随机分配到 4 种处理中的 1 种。处理为：（1）100 g 豆粕载体（对照；CON）；（2）0.75 g/kg BW 的 SB+载体（SB）；（3）1 mg/kg BW 的 MON+载体（MON）；（4）1 mg/kg BW 的 MON+0.75 g/kg BW 的 SB（MSB）。数据使用单自由度对比进行分析，评估 CON 与添加剂（ADD）、SB 与 MON 以及 SB 和 MON 与 MSB 的差异。每天人工混合处理。每天测量饲料和剩料，并在-20°C 下冷冻。剩料样品用于测定干物质（DM），每周取全混合日粮样品，并每月混合以测定 DM 和养分含量。试验开始前和试验第 12 周的每周都测量初始 BW、心围和腹围、体长、血液样本和粪便球虫计数。血液样本用于分析葡萄糖、血浆尿素氮（PUN）和酮浓度。使用酸不溶灰分作为标记物，从第 21 天到第 27 天和第 63 天到第 69 天测定表观全肠道养分消化率。与 CON 相比，ADD 增加了干物质采食量（DMI）和可代谢能采食量，平均 BW、终 BW 和心围趋于增加。尽管 MSB 的心围大于 SB 和 MON，但饲料效率 MON 优于 SB。与 CON 相比，ADD 降低了球虫计数。处理对 PUN 没有影响。与 MSB 相比，MON 和 SB 倾向于有更高的血浆葡萄糖。与 CON 相比，ADD 导致血液酮体浓度平均增加，与 SB 相比，MON 导致血液酮体浓度增加，与 MSB 相比，SB 和 MON 导致血液酮体浓度增加。在第 3 周的消化率阶段，与 MON 相比，SB 组小母牛的 DMI 趋于增加，与 SB 和 MON 相比，MSB 组小母牛的 DMI 也趋于增加。除淀粉消化率外，养分消化率相似，MSB 组小母牛的淀粉消化率高于 SB 和 MON 组小母牛。在第 9 周的消化率阶段，DMI 和养分消化率相似，除了 CON 组的 NDF 高于 ADD 组。总体而言，与 CON 相比，ADD 导致小母牛的生长和球虫减少。
