DeFrain J M, Shirley J E, Titgemeyer E C, Park A F, Ethington R T
Department of Animal Sciences and Industry, Kansas State University, Manhattan 66506, USA.
J Dairy Sci. 2002 Aug;85(8):2000-8. doi: 10.3168/jds.S0022-0302(02)74276-8.
We used four ruminally cannulated, multiparous Holstein cows (690 kg; 21 kg/d milk) in a 2-period crossover design to determine the impact of feeding a raw soybean hull-corn steep liquor pellet (SHSL) on induced subacute ruminal acidosis (SARA) in lactating cows. Cows were fed control [30% alfalfa hay, 15% corn silage, 34% corn, 9% whole cottonseed, 5% soybean meal (SBM)] or SHSL (20% of diet DM) diets as TMR. SHSL replaced 6.2% alfalfa hay, 3.7% corn silage, 6.6% corn, and 3.3% SBM. Periods were 15 d (10 d adaptation, 2 d for prechallenge measures, and 3 d of SARA challenge). Cows were fed once daily at a common DMI dictated by the cow consuming the least. Cows were fasted 12 h before the first SARA challenge. For each of the three SARA challenges, cows were offered 75% of their daily diet at 0600 h. The remaining 25% of diet DM was replaced by ground corn, which was mixed with the orts that remained 2 h after feeding and placed into the rumen. Ruminal pH declined linearly with time after feeding, and this decrease was greater during the SARA challenges. Ruminal lactate increased linearly with repeated SARA challenges. Concentrations of total ruminal VFA increased linearly after feeding, and increases were greater when cows were challenged. No differences were observed due to SHSL inclusion. The model induced SARA, but partial replacement of alfalfa, corn silage, corn, and SBM by SHSL did not influence responses to SARA challenges.
我们采用两期交叉设计，选用了4头安装有瘤胃瘘管的经产荷斯坦奶牛（体重690千克；日产奶量21千克），以确定饲喂生大豆皮-玉米浆颗粒料（SHSL）对泌乳奶牛诱发亚急性瘤胃酸中毒（SARA）的影响。奶牛分别采食对照日粮[30%苜蓿干草、15%玉米青贮、34%玉米、9%全棉籽、5%豆粕（SBM）]或SHSL日粮（占日粮干物质的20%），均制成全混合日粮（TMR）。SHSL替代了6.2%的苜蓿干草、3.7%的玉米青贮、6.6%的玉米和3.3%的豆粕。每期时长为15天（10天适应期、2天用于挑战前测定、3天SARA挑战期）。每天以采食最少的奶牛的采食量为标准，统一给奶牛投喂一次。在第一次SARA挑战前，奶牛禁食12小时。对于三次SARA挑战中的每一次，在06:00给奶牛投喂其日粮的75%。日粮干物质的其余25%用粉碎玉米替代，粉碎玉米与采食后2小时剩余的剩料混合后放入瘤胃。采食后瘤胃pH随时间呈线性下降，且在SARA挑战期间下降幅度更大。瘤胃乳酸随SARA挑战次数的增加呈线性增加。采食后瘤胃总挥发性脂肪酸（VFA）浓度呈线性增加，且在奶牛受到挑战时增加幅度更大。添加SHSL后未观察到差异。该模型诱发了SARA，但用SHSL部分替代苜蓿、玉米青贮、玉米和豆粕并不影响对SARA挑战的反应。
