EFFECTS OF SUPPLEMENTAL PROTEIN PERCENTAGE AND FEEDING LEVEL ON INTAKE, RUMINAL FERMENTATION, AND DIGESTA PASSAGE IN BEEF STEERS FED PRAIRIE HAY
EFFECTS OF SUPPLEMENTAL PROTEIN PERCENTAGE AND FEEDING LEVEL ON INTAKE, RUMINAL FERMENTATION, AND DIGESTA PASSAGE IN BEEF STEERS FED PRAIRIE HAY
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DOI：
10.2527/1992.7051562x
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发表时间：
1992-05-01
影响因子：
3.3
通讯作者：
CATON, JS
中科院分区：
文献类型：
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作者：
FREEMAN, AS;GALYEAN, ML;CATON, JS
12个瘤胃插管公牛（平均初始BW 357公斤）被分配到4个处理（每处理3个公牛）在一个重复的4 × 4拉丁方设计，21天的时间（12天的适应和9天的收集），以比较不同的CP百分比和饲养水平的蛋白质补充剂对低品质牧草利用率的影响。处理为：1）对照组（C），自由采食5.6%CP的草原干草，2）C +600 g DM. steel-1.d-1的基于棉籽粕（PS）的43%CP补充剂，3）C + 1,200 g DM. steel-1.d-1的基于玉米粒和棉籽粕（GS）的22%CP补充剂，（4）C + 600 g DM. steel-1.d-1的22%CP补充剂（基于玉米粒和棉籽粕）（LS）。补饲1 h后，PS组瘤胃总VFA浓度比GS组增加8%（P <0.07）。在添加GS的阉牛中，与PS和LS相比，瘤胃乙酸（mol/100 mol）降低了1.2 mol/100（P <0.03），但与C相比，添加GS对乙酸比例没有影响（P > 0.10）。丙酸盐和丁酸盐均不受补充剂的影响（P > .10），但在补充剂的阉牛中，GS的丁酸盐比例比PS高8%（P < .03），LS的丁酸盐比例比GS和PS的平均值低5%（P < .10）。瘤胃pH值在各处理间差异不显著（P > 10）。瘤胃氨浓度增加1.4至4.8毫克/100毫升（P <0.07），补充和通常低于PS和GS在大多数采样时间的LS。草原干草量（平均值= 16.3 g/kg BW）不受补充剂的影响（P > 0.10）。添加添加剂时，牛的液体稀释率比未添加添加剂时快8%（P <0.01），GS比PS增加4%（P <0.04）。颗粒物通过率不受处理的影响（P > 0.10），但总的道停留时间减少（P <0.01）10%的补充。草原干草NDF原位消化的程度和速率没有受到补充的很大影响，但补充N的原位消失，GS比PS少6 - 10个百分点（P <0.06），LS比PS和GS补充的平均值少2 - 6个百分点。添加PS和GS能增加瘤胃氨含量，但添加LS对瘤胃氨含量无影响，而添加CP和饲喂水平对瘤胃氨含量影响最小。在所使用的饲养水平下，PS和GS都应该有效地满足食用低质量饲料的牛的蛋白质需求。
Twelve ruminally cannulated steers (average initial BW 357 kg) were allotted to four treatments (three steers per treatment) in a replicated 4 x 4 Latin square design with 21-d periods (12 d for adaptation and 9 d for collection) to compare the effects of protein supplements that differed in percentage of CP and feeding level on low-quality forage utilization. Treatments were 1) control (C), ad libitum access to 5.6% CP prairie hay, 2) C +600 g of DM.steer-1.d-1 of a 43% CP supplement based on cottonseed meal (PS), 3) C + 1,200 g of DM.steer-1.d-1 of a 22% CP supplement based on corn grain and cottonseed meal (GS), and 4) C + 600 g of DM.steer-1.d-1 of a 22% CP supplement based on corn grain and cottonseed meal (LS). Ruminal total VFA concentrations were increased 8% (P < .07) by PS vs GS 1 h after supplementation. Among supplemented steers, ruminal acetate (mol/100 mol) was decreased 1.2 mol/100 (P < .03) by GS vs PS and LS; however, supplementation did not affect (P > .10) acetate proportions compared with C. Neither propionate nor butyrate was affected (P > .10) by supplementation, but among supplemented steers, butyrate proportions were 8% greater (P < .03) for GS than for PS and 5% less (P < .10) for LS than for the average of GS and PS. Ruminal pH did not differ (P > 10) among treatments. Ruminal ammonia concentrations were increased 1.4 to 4.8 mg/100 mL (P < .07) by supplementation and typically were less for LS than for PS and GS at most sampling times. Prairie hay DMI (average = 16.3 g/kg BW) was not affected (P > .10) by supplementation. Fluid dilution rate was 8% faster (P < .01) when steers were supplemented than when they were not fed supplement, and fluid dilution rate was increased 4% (P < .04) by GS compared with PS. Particulate digesta passage rate was not affected (P > .10) by treatment, but total tract retention time was decreased (P < .01) 10% by supplementation. Extent and rate of prairie hay NDF digestion in situ were not greatly affected by supplementation, but in situ disappearance of supplement N was 6 to 10 percentage units less (P < .06) for GS than for PS and 2 to 6 percentage units less for LS than for the average of PS and GS supplements. The PS and GS supplements, but not the LS supplement, increased ruminal ammonia, but percentage of CP in supplements and feeding level had minimal effects on forage DMI. At the feeding levels used, both PS and GS should be effective for meeting the protein requirements of cattle consuming low-quality forage.