以两种不同比例提供玉米或碎粒饲料作为补充料时，泌乳期肉牛对百慕大干草的采食量、消化率、瘤胃发酵及原位消失率

Intake, Digestibility, Ruminal Fermentation, and In Situ Disappearance of Bermudagrass Hay by Lactating Beef Cows Offered Corn or Hominy Feed as Supplements at Two Different Rates.

作者信息

Nieman Christine C, Madzonga Zibani, Young-Kenworthy Ashley N, Coffey Kenneth P

机构信息

USDA-ARS Dale Bumpers Small Farms Research Center, Booneville, AR 72927, USA.

Department of Agricultural Research, Francistown P.O. Box 10275, Botswana.

出版信息

Animals (Basel). 2023 Jun 1;13(11):1845. doi: 10.3390/ani13111845.

DOI:10.3390/ani13111845

PMID:37889783

原文链接:https://pmc.ncbi.nlm.nih.gov/articles/PMC10251856/

Abstract

Hominy feed (HF) has been evaluated in feedlot and dairy rations but has not been evaluated as a supplemental energy source for lactating beef cows. The objective of this study was to determine the effect of level of HF supplementation on intake, digestibility, ruminal fermentation characteristics, and in situ dry matter (DM) disappearance of bermudagrass hay. Five ruminally cannulated lactating beef cows (body weight (BW) = 596 kg, SE = 13.9) were used in an experiment with a 5 × 5 Latin square design. Treatments were a bermudagrass hay-basal diet with low HF (LH; 0.25% BW), medium HF (MH; 0.50% BW), low ground corn (LC; 0.25% BW), medium ground corn (MC; 0.50% BW) and no supplement (CON). Cows were housed individually, and supplements were offered at 0800 daily. Hay was offered to maintain 10% refusal. Periods were 16-d, with 10 d for adaptation. Ruminal fluid was sampled on d 14 of each period for measurement of pH, volatile fatty acids, and rumen ammonia-N. An in situ degradation experiment for bermudagrass hay was completed for each diet. Hay dry-matter intake (DMI % BW) was not affected ( = 0.14) by supplement, but total DMI (DMI % BW) was greater ( ≤ 0.05) in MH and MC compared to LH and CON. Digestible DMI % BW was greater ( = 0.05) in MH compared to LC, MC was intermediate, and LH and CON were lesser ( ≤ 0.01) than all other diets. Dry-matter fill, passage rate, and retention time did not differ by diet ( ≥ 0.31). A diet × time interaction was observed for ammonia-N ( = 0.0002), and propionate ( = 0.02) time effects were observed for other parameters, but no diet effects. Bermudagrass hay's potentially degradable fraction was greater ( ≤ 0.05) in LH than MH and CON, but effective DM degradability was not different ( = 0.39) among diets. Overall, no diets reduced hay intake or disappearance compared to CON; therefore, no negative associative effects were observed from any of the supplements at the levels offered in this study.

摘要

碎粒饲料（HF）已在育肥牛和奶牛日粮中进行了评估，但尚未作为泌乳期肉牛的补充能量来源进行评估。本研究的目的是确定补充不同水平HF对百慕大干草的采食量、消化率、瘤胃发酵特性和原位干物质（DM）消失率的影响。选用5头安装了瘤胃瘘管的泌乳期肉牛（体重（BW）=596 kg，标准误=13.9），采用5×5拉丁方设计进行试验。处理组包括低HF（LH；0.25%体重）、中HF（MH；0.50%体重）的百慕大干草基础日粮，低玉米粉（LC；0.25%体重）、中玉米粉（MC；0.50%体重）的百慕大干草基础日粮以及不补充任何物质（CON）。每头牛单独饲养，每天08:00提供补充料。提供干草以维持10%的剩料量。试验期为16天，其中10天用于适应期。在每个试验期的第14天采集瘤胃液，用于测定pH值、挥发性脂肪酸和瘤胃氨氮。对每种日粮的百慕大干草进行了原位降解试验。干草干物质采食量（DMI占体重的百分比）不受补充料的影响（P = 0.14），但与LH和CON相比，MH和MC组的总DMI（DMI占体重的百分比）更高（P≤0.05）。与LC相比，MH组的可消化DMI占体重的百分比更高（P = 0.05），MC组居中，LH和CON组低于所有其他日粮（P≤0.01）。日粮间的干物质填充量、通过率和滞留时间没有差异（P≥0.31）。观察到氨氮存在日粮×时间的交互作用（P = 0.0002），其他参数存在丙酸的时间效应（P = 0.02），但日粮间没有影响。LH组百慕大干草的潜在可降解部分高于MH和CON组（P≤0.05），但日粮间有效DM降解率没有差异（P = 0.39）。总体而言，与CON组相比，没有任何日粮降低了干草采食量或消失率；因此，在本研究提供的水平下，没有观察到任何补充料产生负面的协同效应。