Mandell I B, Buchanan-Smith J G, Campbell C P
Department of Animal and Poultry Science, University of Guelph, Ontario, Canada.
J Anim Sci. 1998 Oct;76(10):2619-30. doi: 10.2527/1998.76102619x.
Limousin-cross steers (n=135; 258+/-26 kg) were used to compare forage vs grain feeding on carcass composition and palatability attributes of beef when time on feed was controlled. Diets included a 95% alfalfa silage ration (AS) or a 68% high-moisture corn, 25% alfalfa silage ration (HMC). These were incorporated into six treatments to allow comparisons of end points based on similar days on feed or backfat finish. Dietary treatments included 1) HMC (4 mm), or cattle allowed ad libitum intake of HMC until slaughter at 4 mm ultrasound backfat; 2) AS (HMC-4), or cattle allowed ad libitum intake of AS until slaughter, regardless of finish, when HMC (4 mm) cattle were slaughtered; 3) AS (4 mm), or cattle allowed ad libitum intake of AS until slaughter at 4 mm backfat; 4) HMC (AS-4), or cattle allowed ad libitum intake of HMC until slaughter, regardless of finish, when AS (4 mm) cattle achieved 4 mm backfat; 5) HMC (RES), or cattle fed HMC at restricted intakes until slaughter at 4 mm backfat with feed offered at 75% of intake achieved by HMC (4 mm) and HMC (AS-4) cattle; and 6) AS (8 mm) or cattle allowed ad libitum intake of AS ration until slaughter at 8 mm backfat. Grain feeding generally increased (P < .01) ADG, carcass weight, grade fat, and intramuscular fat content when compared with forage feeding at similar times on feed. Palatability attributes of ribeye roasts and ground beef were generally unaffected (P > .10) by diet with the exception of slightly less beef flavor and more off-flavor in forage-fed vs grain-fed beef. Higher (P < .01) concentrations of linolenic acid and lower (P < .10) concentrations of oleic acid in forage-fed beef may be partially responsible for diet differences in flavor.
选用利木赞杂交阉牛（n = 135；体重258±26千克），在控制饲养时间的情况下，比较饲草喂养与谷物喂养对牛肉胴体组成和适口性指标的影响。日粮包括95%的苜蓿青贮日粮（AS）或68%的高水分玉米、25%的苜蓿青贮日粮（HMC）。将这些日粮组合成六种处理方式，以便根据相似的饲养天数或背膘厚度来比较终点指标。日粮处理方式包括：1）HMC（4毫米），即牛自由采食HMC，直至超声背膘厚度达到4毫米时屠宰；2）AS（HMC - 4），即牛自由采食AS，直至与HMC（4毫米）组牛屠宰时相同的时间点屠宰，不论背膘厚度如何；3）AS（4毫米），即牛自由采食AS，直至背膘厚度达到4毫米时屠宰；4）HMC（AS - 4），即牛自由采食HMC，直至与AS（4毫米）组牛达到4毫米背膘厚度时相同的时间点屠宰，不论背膘厚度如何；5）HMC（RES），即牛以限量方式采食HMC，直至背膘厚度达到4毫米时屠宰，提供的饲料量为HMC（4毫米）组和HMC（AS - 4）组牛采食量的75%；6）AS（8毫米），即牛自由采食AS日粮，直至背膘厚度达到8毫米时屠宰。与在相似饲养时间内的饲草喂养相比，谷物喂养通常会使平均日增重（ADG）、胴体重、脂肪等级和肌内脂肪含量增加（P < 0.01）。除了饲草喂养的牛肉比谷物喂养的牛肉风味略淡且异味更多外，肋眼牛排和碎牛肉的适口性指标通常不受日粮影响（P > 0.10）。饲草喂养的牛肉中较高（P < 0.01）的亚麻酸浓度和较低（P < 0.10）的油酸浓度可能是造成风味日粮差异的部分原因。
