Sainz R D, De la Torre F, Oltjen J W
Department of Animal Science, University of California, Davis 95616, USA.
J Anim Sci. 1995 Oct;73(10):2971-9. doi: 10.2527/1995.73102971x.
Beef steers were fed in two phases 1) to determine the relative importance of changes in DMI, gastrointestinal tract fill, energy expenditures, and composition of gain in the compensatory growth phenomenon, 2) to compare the effects of growth restriction due to ad libitum consumption of a low-energy (low-concentrate) diet to those of limited intake of a high-energy (high-concentrate) feed, and 3) to examine changes in carcass composition and quality resulting from different types of growth restriction. During the growing phase (237 to 327 kg), steers were fed either a high- (C) of low- (F) concentrate diet. Diet F was available for ad libitum consumption (FA) and diet C was available either for ad libitum consumption (CA) or on a limited basis (CL) to match the live weight gains by the FA group. During the finishing phase (327 to 481 kg), all steers received diet C, either for ad libitum consumption (CA) or restricted (CL) to 70% of the intake by the corresponding CA steers. Backfat thickness was markedly reduced (P < .001) by final feed restriction (7.4 and 6.9 mm for CL-CL and FA-CL respectively), compared with CA-CA (12.6 mm). Backfat also was lower in CL-CA (11.6 mm, P < .10) and FA-CA (9.9 mm, P < .05) than in CA-CA steers. Conversely, marbling scores were similar among groups, except for the FA-CL steers, which had lower marbling scores than FA-CA and CL-CA steers (P < .05). Higher DMI following growth restriction were accompanied by increased rates of live weight (+54 and +27%) and empty body weight (EBW; +57 and +43%) gain for CL-CA and FA-CA steers, respectively, compared with CA-CA steers. Gain:feed (EBW basis) were improved in some restricted/refed groups (+30, +13, and +10%, for Cl-CA, CL-CM respectively CA-CA. Increased DMI played a major role in the compensatory gain response in both CL-CA and FA-CA groups. Maintenance requirement was reduced (-17%) in CL-CA and increased in the FA-CA group (+21%); both changes affected the magnitude of compensatory gain in those animals. In contrast, composition of gain had little or no effect on the compensatory gain response. Programmed feeding can be used to manipulate carcass quality, but low-concentrate feeding during the growing phase may impair overall feedlot performance.
1）确定干物质采食量（DMI）变化、胃肠道充盈度、能量消耗以及补偿生长现象中增重组成的相对重要性；2）比较自由采食低能量（低精料）日粮导致的生长受限与限量采食高能量（高精料）饲料所产生的影响；3）研究不同类型生长受限对胴体组成和品质的影响。在生长阶段（237至327千克），给肉牛饲喂高（C）或低（F）精料日粮。日粮F可供自由采食（FA），日粮C可供自由采食（CA）或限量采食（CL），以使CL组的活体重增加量与FA组相匹配。在育肥阶段（327至481千克），所有肉牛均采食日粮C，要么自由采食（CA），要么限制采食（CL），采食量为相应CA组肉牛采食量的70%。与CA-CA组（12.6毫米）相比，最终限饲使背膘厚度显著降低（P < 0.001）（CL-CL和FA-CL组分别为7.4和6.9毫米）。CL-CA组（11.6毫米，P < 0.10）和FA-CA组（9.9毫米，P < 0.05）的背膘厚度也低于CA-CA组肉牛。相反，除FA-CL组肉牛大理石花纹评分低于FA-CA组和CL-CA组（P < 0.05）外，各处理组间大理石花纹评分相似。与CA-CA组肉牛相比，CL-CA组和FA-CA组肉牛在生长受限后较高的DMI分别伴随着更高的活体重（+54%和+27%）和空体重（EBW；+57%和+43%）增加率。部分限饲/再饲喂组的增重：饲料比（以EBW计）有所提高（Cl-CA、CL-CM和CA-CA组分别提高30%、13%和10%）。CL-CA组和FA-CA组中，DMI增加在补偿性增重反应中起主要作用。CL-CA组的维持需要量降低（-17%），FA-CA组增加（+21%）；这两种变化均影响了这些动物的补偿性增重幅度。相比之下，增重组成对补偿性增重反应影响很小或没有影响。程序化饲喂可用于控制胴体品质，但生长阶段低精料饲喂可能会损害整个育肥期的性能。
