Villalba J J, Cabassu R, Gunter S A
J Anim Sci. 2015 Apr;93(4):1729-40. doi: 10.2527/jas.2014-8667.
We determined if combinations of adjacent pastures of 3 forage species led to complementary relationships that influenced animal behavior and performance over monocultures. Grazing bouts, behavioral levels of activity, blood urea N (BUN), chemical composition of feces, BW, and herbage biomass before and after grazing were monitored when beef calves strip-grazed 3 replications of 4 treatments from June 14 through August 23, 2013 (9 animals/treatment). Animals grazed monocultures of: 1) tall fescue (TF), 2) alfalfa (ALF), 3) sainfoin (SAN), or 4) a choice of strips of forages TF, ALF, and SAN (CHOICE). The lowest and greatest incidence of foraging bouts occurred for cattle in CHOICE and SAN, respectively (P < 0.01). Animals in CHOICE grazed SAN > ALF > TF (P < 0.01). Animals on TF and CHOICE took greater number of steps than animals grazing a monocultures of either legume (P = 0.01). Calves in TF had lower BUN (P < 0.01) and fecal CP concentration (P < 0.01) than calves grazing the remaining treatments, whereas animals in SAN showed the greatest concentrations of fecal CP (P < 0.01). Fecal NDF concentration was the greatest for animals grazing TF and the lowest for animals grazing SAN (P < 0.01), whereas fecal ADF concentration was greater for animals grazing TF and SAN than for animals grazing CHOICE and ALF (P = 0.02). Calcium, Mg, and Zn concentrations were the lowest in feces from calves grazing TF and the greatest for calves grazing a monoculture of either legume (P < 0.05). When averaging both periods, animals grazing SAN, ALF, or CHOICE gained more BW than animals grazing TF (P < 0.01). Thus, calves in CHOICE incorporated tall fescue into their diets, were more active, and displayed a lower number of grazing bouts than calves grazing monoculture of either legume. Herbage diversity may lead to levels of ADG comparable to legume monocultures with the potential benefit of maintaining plant species diversity in pasturelands.
我们研究了三种饲草物种相邻牧场的组合是否会产生互补关系，从而影响动物行为及与单一栽培相比的生产性能。2013年6月14日至8月23日，肉牛犊对4种处理进行3次重复条带放牧（每个处理9头动物）时，监测了放牧回合、行为活动水平、血尿素氮（BUN）、粪便化学成分、体重以及放牧前后的牧草生物量。动物放牧单一栽培的：1）高羊茅（TF），2）苜蓿（ALF），3）红豆草（SAN），或4）高羊茅、苜蓿和红豆草条带的组合（CHOICE）。采食回合发生率最低和最高的分别是CHOICE组和SAN组的牛（P < 0.01）。CHOICE组的动物采食红豆草 > 苜蓿 > 高羊茅（P < 0.01）。TF组和CHOICE组的动物比放牧单一豆科植物的动物走的步数更多（P = 0.01）。TF组的犊牛血尿素氮（P < 0.01）和粪便粗蛋白浓度（P < 0.）低于放牧其他处理的犊牛，而SAN组动物的粪便粗蛋白浓度最高（P < 0.01）。放牧TF的动物粪便中性洗涤纤维浓度最高，放牧SAN的动物最低（P < 0.01），而放牧TF和SAN的动物粪便酸性洗涤纤维浓度高于放牧CHOICE和ALF的动物（P = 0.02）。放牧TF的犊牛粪便中钙、镁和锌的浓度最低，放牧单一豆科植物的犊牛最高（P < 0.05）。平均两个时期，放牧SAN、ALF或CHOICE的动物比放牧TF的动物体重增加更多（P < 0.01）。因此，与放牧单一豆科植物的犊牛相比，CHOICE组的犊牛将高羊茅纳入其日粮，更活跃，采食回合次数更少。牧草多样性可能导致与豆科单一栽培相当的平均日增重水平，并有可能在牧场维持植物物种多样性。
