Olson K C, Cochran R C, Jones T J, Vanzant E S, Titgemeyer E C, Johnson D E
Department of Animal Sciences and Industry, Kansas State University, Manhattan 66506, USA.
J Anim Sci. 1999 Apr;77(4):1016-25. doi: 10.2527/1999.7741016x.
Hereford x Angus steers were used in a 13-treatment, four-period, incomplete Latin square design to examine the effects of starch and degradable intake protein (DIP) supplements on forage utilization and ruminal function. Steers were given ad libitum access to low-quality hay (4.9% CP) and were not supplemented (NS) or received different amounts of starch (cornstarch grits; 0, .15, and .3% of initial BW) and DIP (Na-caseinate; .03, .06, .09, and .12% of initial BW) administered via ruminal fistulae in a 3 x 4 factorial arrangement of treatments. Supplemented steers consumed more (P < .01) forage OM, total OM, NDF, and digestible OM (DOM) than NS steers. Forage OM, total OM, NDF, and DOM intakes increased linearly (P < .01) as the amount of supplemental DIP increased. The addition of starch to supplements linearly decreased ( P < .01) the intake of forage OM, NDF, and DOM. The digestion of DM, OM, and NDF increased linearly (P < .01) with supplemental DIP and decreased linearly (P < or = .06) with supplemental starch. Particulate and liquid passages generally increased with DIP; however, starch level influenced the nature of the response (P = .03 and .06, respectively). Similarly, ruminal acid detergent-insoluble ash content generally decreased as starch increased, but the effect was dependent on DIP level (P < .01). Supplementation increased (P < .01) ruminal NH3 and total VFA and decreased (P < .01) ruminal pH relative to NS. All treatments supported average pH values in a range (6.3 to 6.7) unlikely to inhibit fibrolytic bacteria. Ruminal NH3 concentration increased quadratically (P = .03) with DIP and decreased linearly (P = .02) with starch. As DIP increased, total VFA concentration increased linearly (P = .02). Providing supplemental DIP to steers fed low-quality forage increased OM intake and digestion, whereas addition of starch to supplements decreased forage intake and digestion.
使用赫里福德牛与安格斯牛杂交的阉牛，采用13种处理、4个阶段的不完全拉丁方设计，以研究淀粉和可降解摄入蛋白（DIP）补充剂对草料利用率和瘤胃功能的影响。阉牛可随意采食低质量干草（粗蛋白含量4.9%），不进行补充（NS）或接受不同量的淀粉（玉米淀粉粗粒；初始体重的0、0.15和0.3%）和DIP（酪蛋白酸钠；初始体重的0.03、0.06、0.09和0.12%），通过瘤胃瘘管以3×4析因处理安排给予。与未补充的阉牛相比，补充处理的阉牛消耗了更多（P<0.01）的草料有机物质（OM）、总有机物质、中性洗涤纤维（NDF）和可消化有机物质（DOM）。随着补充DIP量的增加，草料OM、总OM、NDF和DOM摄入量呈线性增加（P<0.01）。在补充剂中添加淀粉使草料OM、NDF和DOM的摄入量呈线性下降（P<0.01）。干物质（DM）、OM和NDF的消化率随着补充DIP呈线性增加（P<0.01），随着补充淀粉呈线性下降（P≤0.06）。颗粒和液体通过率通常随着DIP增加；然而，淀粉水平影响反应的性质（分别为P = 0.03和0.06）。同样，瘤胃酸洗涤剂不溶性灰分含量通常随着淀粉增加而下降，但效果取决于DIP水平（P<0.01）。与未补充相比，补充增加了（P<0.01）瘤胃氨和总挥发性脂肪酸（VFA），降低了（P<0.01）瘤胃pH值。所有处理的平均pH值都在一个不太可能抑制纤维分解菌的范围内（6.3至6.7）。瘤胃氨浓度随着DIP呈二次方增加（P = 0.03），随着淀粉呈线性下降（P = 0.02）。随着DIP增加，总VFA浓度呈线性增加（P = 0.02）。给采食低质量草料的阉牛提供补充DIP可增加OM摄入量和消化率，而在补充剂中添加淀粉则会降低草料摄入量和消化率。
