Vanzant E S, Cochran R C
Department of Animal Sciences and Industry, Kansas State University, Manhattan 66506.
J Anim Sci. 1994 Apr;72(4):1059-67. doi: 10.2527/1994.7241059x.
Two experiments evaluated effects of amount of supplemental alfalfa hay on intake and utilization of dormant, tallgrass-prairie forage by beef steers and on performance of cows grazing tallgrass prairie during winter. In Exp. 1, four supplemental alfalfa levels (.23, .47, .70, and .94% BW.steer-1.d-1) were evaluated in a 34-d, randomized complete block design experiment using 16 steers (291 kg). Voluntary tallgrass-prairie hay intake decreased linearly (P = .02), whereas total DMI increased linearly (P < .01) with increased alfalfa. Dry matter digestibility was unaffected (P > .10) by treatment, although NDF digestibility decreased (linear, P = .03) and passage rates of indigestible ADF and Cr EDTA increased (linear, P = .02) with increased alfalfa. In Exp. 2, supplemental alfalfa (.48, .72, or .96% BW.cow-1.d-1) was fed to 113 pregnant Hereford x Angus cows (502 kg) from November 27 until calving (average calving date = March 7). Cumulative weight loss from the beginning of the experiment until just after calving was lowest with .96% BW alfalfa (quadratic, P = .09), and cumulative condition loss was decreased linearly (P = .02) with increased alfalfa. Although treatment did not alter (P > .10) pregnancy rates, increasing the amount of alfalfa supported shorter intervals to conception (P = .03). Cows fed .96% BW alfalfa weaned heavier calves (quadratic, P = .04) than other groups. Results indicate that improvements in performance of beef cows in moderate body condition were greater when the amount of supplemental alfalfa was increased from .48 to .72% BW than when it was increased from .72 to .96% BW.(ABSTRACT TRUNCATED AT 250 WORDS)
两项试验评估了补充苜蓿干草量对肉用公牛采食和利用休眠高草草原牧草的影响，以及对冬季放牧高草草原母牛生产性能的影响。在试验1中，采用34天随机完全区组设计试验，对16头公牛（291千克）评估了四个苜蓿补充水平（每头公牛每天0.23%、0.47%、0.70%和0.94%体重）。随着苜蓿量增加，高草草原干草的自愿采食量呈线性下降（P = 0.02），而总干物质采食量呈线性增加（P < 0.01）。处理对干物质消化率无影响（P > 0.10），但随着苜蓿量增加，中性洗涤纤维消化率下降（线性，P = 0.03），酸性洗涤纤维和铬乙二胺四乙酸不可消化部分的通过率增加（线性，P = 0.02）。在试验2中，从11月27日至产犊（平均产犊日期为3月7日），对113头怀孕的赫里福德×安格斯母牛（502千克）饲喂补充苜蓿（每头母牛每天0.48%、0.72%或0.96%体重）。从试验开始至产犊后，体重累积损失以0.96%体重苜蓿组最低（二次曲线，P = 0.09），随着苜蓿量增加，体况累积损失呈线性下降（P = 0.02）。虽然处理对妊娠率无影响（P > 0.10），但增加苜蓿量可缩短受孕间隔时间（P = 0.03）。饲喂0.96%体重苜蓿的母牛所产犊牛断奶时体重比其他组重（二次曲线，P = 0.04）。结果表明，中等体况的肉用母牛，补充苜蓿量从0.48%体重增加到0.72%体重时，生产性能的改善幅度大于从0.72%体重增加到0.96%体重时。（摘要截短为250字）
