Radunz A E, Fluharty F L, Day M L, Zerby H N, Loerch S C
Department of Animal Sciences, The Ohio State University, Wooster, Ohio 44691, USA.
J Anim Sci. 2010 Aug;88(8):2717-28. doi: 10.2527/jas.2009-2744. Epub 2010 May 7.
Mature Angus-cross beef cows (n = 144) were used to determine effects of late gestation dietary energy source on pre- and postpartum cow performance in a complete randomized block design experiment. Cows were adapted to diets starting at 167 +/- 9 d of gestation and fed until 1 wk before expected calving date. Cows were fed 1 of 3 dietary energy sources: grass hay (HY), corn (CN), or dried distillers grains (DDGS). Cows allotted to HY were allowed ad libitum access to round-bale grass hay, and average hay disappearance was 12.4 kg/d. Limit-fed corn and DDGS diets contained 5.3 kg of whole-shelled corn or 4.1 kg of DDGS, respectively, plus 2.1 kg of hay, and 1.0 kg of supplement to meet cow nutritional needs during late gestation and to allow for an energy intake similar to HY. Every 21 d, BW, BCS, and ultrasound measurement of backfat between the 12th and 13th ribs were collected. At 210 d in gestation, jugular blood samples were collected from cows at 0, 3, 6, and 9 h postfeeding and were analyzed for glucose, insulin, NEFA, and blood urea N (BUN) concentrations. After parturition, cows were fed a common diet and managed similarly. Milk production was determined by weigh-suckle-weigh procedure on d 31, 100, and 176 postpartum. Cows fed DDGS during late gestation gained more (P = 0.04) BW than cows fed HY or CN; however, no difference in BCS change was detected (P = 0.28) among treatments. Plasma glucose concentrations were similar among treatments (P = 0.64), whereas insulin concentrations at 3 h postfeeding were greater (P = 0.002) for cows fed DDGS than those fed HY or CN. Plasma BUN concentrations were greater (P < or = 0.02) for cows fed DDGS vs. CN or HY up to 6 h postfeeding. Birth weight was greater (P < 0.001) for calves from cows fed CN and DDGS than for those fed HY, but this did not result in any differences in frequency of dystocia (P = 0.21). Prepartum energy source did not affect conception rates (P = 0.79), milk production (P > or = 0.51), or milk composition (P > or = 0.39). Maternal dietary energy source in late gestation did not affect pre- or postpartum cow performance, but did change plasma hormones and metabolites during gestation. Heavier birth weights in calves from cows fed CN or DDGS indicate the changes in maternal metabolism affected energy partitioning of nutrients to the fetus and subsequent fetal growth.
在一项完全随机区组设计实验中，选用144头成年安格斯杂交肉牛母牛，以确定妊娠后期日粮能量来源对产前和产后母牛生产性能的影响。母牛从妊娠167±9天开始适应日粮，一直饲喂到预计产犊日期前1周。母牛被饲喂3种日粮能量来源中的1种：禾本科干草（HY）、玉米（CN）或干酒糟（DDGS）。分配到HY组的母牛可自由采食圆捆禾本科干草，平均干草采食量为12.4千克/天。限量饲喂的玉米和DDGS日粮分别包含5.3千克带壳整粒玉米或4.1千克DDGS，外加2.1千克干草和1.0千克补充料，以满足母牛妊娠后期的营养需求，并使能量摄入量与HY组相似。每21天采集一次体重（BW）、体况评分（BCS）以及第12和13肋骨间背膘的超声测量值。在妊娠210天时，于饲喂后0、3、6和9小时从母牛颈静脉采集血样，分析葡萄糖、胰岛素、非酯化脂肪酸（NEFA）和血尿素氮（BUN）浓度。分娩后母牛饲喂普通日粮并进行相似管理。在产后第31、100和176天通过称重-哺乳-称重程序测定产奶量。妊娠后期饲喂DDGS的母牛比饲喂HY或CN的母牛体重增加更多（P = 0.04）；然而，各处理间BCS变化未检测到差异（P = 0.28）。各处理间血浆葡萄糖浓度相似（P = 0.64），而饲喂DDGS的母牛在饲喂后3小时的胰岛素浓度高于饲喂HY或CN的母牛（P = 0.002）。饲喂DDGS的母牛在饲喂后6小时内的血浆BUN浓度高于饲喂CN或HY的母牛（P≤0.02）。饲喂CN和DDGS的母牛所产犊牛的出生体重高于饲喂HY的母牛（P < 0.001），但这并未导致难产发生率出现任何差异（P = 0.21）。产前能量来源不影响受孕率（P = 0.79）、产奶量（P≥0.51）或乳成分（P≥0.39）。妊娠后期母体日粮能量来源不影响产前或产后母牛生产性能，但确实改变了妊娠期间的血浆激素和代谢产物。饲喂CN或DDGS的母牛所产犊牛出生体重较重，表明母体代谢变化影响了营养物质向胎儿的能量分配以及随后的胎儿生长。
