Linneen S K, McGee A L, Cole J R, Jennings J S, Stein D R, Horn G W, Lalman D L
J Anim Sci. 2015 Jun;93(6):3076-83. doi: 10.2527/jas.2014-8406.
Two experiments were designed to investigate the effects of feeding monensin and/or slow release urea with a fibrolytic feed enzyme (Optimase; Alltech, Inc., Nicholasville, KY) on performance, milk production, calf growth performance, and blood metabolites in beef cows. Spring-calving cows and heifers were used in a completely randomized design in Exp. 1 (N = 84; 534 ± 68 kg initial BW) and Exp. 2 (N = 107; 508 ± 72 kg initial BW). Exp. 1 supplements were formulated to meet cow protein requirements and fed daily and included 1) cottonseed meal with no monensin (control); or 2) monensin added to control to supply 200 mg per head per d (MON). In Exp. 2, experimental supplements included 1) cottonseed meal/wheat middlings (CS) fed at a rate to provide adequate DIP and CP according to , 2) the CS plus soybean hulls and 61 g per cow per d Optimase (OPT), 3) the CS plus monensin to supply 200 mg per cow per d (MON2), and 4) OPT plus MON2 (Combo). Cows were fed in last trimester through early lactation in Exp. 1 and during 2nd trimester in Exp. 2. Data were analyzed using the Mixed procedure in SAS with animal as the experimental unit. In Exp. 1, treatment did not affect cow BW or BCS change (P > 0.19). Calf birth BW was not affected by dam treatment (P = 0.24); however, calves from dams consuming MON weighed more (P < 0.04) at d 45 and at trial end. Calves also had greater (P = 0.04) ADG from birth to trial end. Milk production did not significantly differ among treatments (P > 0.41). In Exp. 2, mean cow BW and BCS were similar (P > 0.35) among treatments on d 90. However, from d 0 to 54, cows assigned to the OPT supplement gained less BCS (P = 0.02) compared with cows assigned to the CS supplement. Cumulative BCS gain was greater (P < 0.01) for CS-fed cows than for cows fed the OPT and MON2 supplements, although it was not significantly different for cows fed the Combo supplement. These studies indicate that the influence of monensin on cow BW and BCS change is inconsistent. The potential for monensin supplementation to positively impact calf performance during early lactation seems to be clearer. Replacing a portion of oilseed N in the supplement with Optimase may marginally reduce cow performance. Further research is needed to determine both the effects of monensin and the implications of combining monensin with Optimase on forage intake and cow performance at various stages of production.
设计了两项试验，以研究给肉牛饲喂莫能菌素和/或缓释尿素并添加纤维分解酶（Optimase；奥特奇公司，肯塔基州尼古拉斯维尔）对其生产性能、产奶量、犊牛生长性能和血液代谢物的影响。在试验1（N = 84；初始体重534±68千克）和试验2（N = 107；初始体重508±72千克）中，春季产犊的母牛和小母牛采用完全随机设计。试验1的补充料配方旨在满足母牛的蛋白质需求，每天饲喂，包括1）不添加莫能菌素的棉籽粕（对照）；或2）在对照中添加莫能菌素，每头每天供应200毫克（MON）。在试验2中，试验补充料包括1）按照提供适量可消化不可降解蛋白（DIP）和粗蛋白（CP）的比例饲喂棉籽粕/小麦麸（CS），2）CS加大豆皮和每头母牛每天61克Optimase（OPT），3）CS加莫能菌素，每头母牛每天供应200毫克（MON2），以及4）OPT加MON2（组合）。试验1中，母牛在妊娠后期至泌乳早期饲喂；试验2中，母牛在妊娠中期饲喂。数据采用SAS中的混合程序进行分析，以动物作为试验单位。在试验1中，处理对母牛体重或体况评分变化没有影响（P>0.19）。犊牛出生体重不受母畜处理的影响（P = 0.24）；然而，采食MON的母畜所产犊牛在45日龄和试验结束时体重更重（P<0.04）。从出生到试验结束，犊牛的平均日增重也更高（P = 0.04）。各处理间的产奶量没有显著差异（P>0.41）。在试验2中，90日龄时各处理间母牛的平均体重和体况评分相似（P>0.35）。然而，从第0天到第54天，与采食CS补充料的母牛相比，采食OPT补充料的母牛体况评分增加较少（P = 0.02）。采食CS的母牛累计体况评分增加量大于采食OPT和MON2补充料的母牛（P<0.01），不过采食组合补充料的母牛与采食CS的母牛之间没有显著差异。这些研究表明，莫能菌素对母牛体重和体况评分变化的影响并不一致。在泌乳早期，补充莫能菌素对犊牛性能产生积极影响的潜力似乎更明显。用Optimase替代补充料中一部分油籽氮可能会略微降低母牛的生产性能。需要进一步研究以确定莫能菌素的影响以及莫能菌素与Optimase组合对不同生产阶段的采食量和母牛生产性能的影响。
