Hyun Y, Ellis M, Johnson R W
Department of Animal Sciences, University of Illinois, Urbana 61801, USA.
J Anim Sci. 1998 Nov;76(11):2771-8. doi: 10.2527/1998.76112771x.
The effect of crowding and mixing on growth performance and feed intake pattern were investigated in growing pigs in a 4-wk study. Feeding pattern was monitored using automated feed intake recording equipment (F.I.R.E.). A total of 256 Yorkshire x Hampshire and purebred Duroc pigs (initial weight 35.8+/-.86 kg) were allocated to one of the eight treatment combinations in a 2x2x2 factorial arrangement (feeder type [conventional feeder vs F.I.R.E. feeder], space allowance [.56 vs .25 m2/pig], and mixing strategy [mixed vs unmixed; mixing at start of wk 1 and 3]). Pigs were housed in groups of eight, balanced for genotype and sex (barrows and gilts), and had free access to a corn-soybean meal diet (17% crude protein, 3,296 kcal ME/kg). There was no difference in growth performance between feeder types. Crowding and mixing had no effect on daily feed intake but they depressed growth rate by 15.7 and 7.1%, respectively, and the effects of the two stressors were additive. Gain:feed ratio was reduced by crowding (10.0%) but not by mixing. Crowded pigs made fewer (11.2 vs 15.7; SEM = .51), and longer (12.5 vs 8.9 min; SEM .41) feeder visits and had higher feed intake per visit (196.2 vs 145.5 g; SEM = 5.94) than uncrowded animals. Mixing produced changes in feeding pattern in the 1st wk after mixing but not over the 4-wk period. This study showed that crowding and mixing depressed growth rates in an additive manner and altered feeding behavior.
在一项为期4周的研究中，对生长猪进行了饲养密度和混群饲养对生长性能及采食量模式的影响的研究。使用自动采食量记录设备（F.I.R.E.）监测采食模式。总共256头约克夏×汉普夏和纯种杜洛克猪（初始体重35.8±0.86千克），按照2×2×2析因设计被分配到8种处理组合之一（饲养器类型[传统饲养器与F.I.R.E.饲养器]、空间占有量[0.56 vs 0.25平方米/头]和混群策略[混群与不混群；在第1周和第3周开始时混群]）。猪以每组8头进行饲养，按基因型和性别（阉公猪和小母猪）均衡分组，自由采食玉米-豆粕型日粮（粗蛋白17%，代谢能3296千卡/千克）。不同饲养器类型的生长性能没有差异。饲养密度和混群饲养对每日采食量没有影响，但分别使生长速度降低了15.7%和7.1%，且两种应激源的影响是累加的。增重：饲料比因饲养密度而降低（10.0%），但不受混群饲养的影响。与饲养密度正常的猪相比，饲养密度大的猪采食次数更少（11.2次对15.7次；标准误=0.51），采食时间更长（12.5分钟对8.9分钟；标准误0.41），每次采食的采食量更高（196.2克对145.5克；标准误=5.94）。混群饲养在混群后的第1周引起了采食模式的变化，但在4周期间内没有持续影响。本研究表明，饲养密度和混群饲养以累加的方式降低了生长速度并改变了采食行为。
