Intake and performance of beef steers with ad libitum access to a balanced ration or the same ingredients of the balanced diet but delivered in separated bunks

ARROQUY, J.I.; J. SARAVIA; A. FUMAGALLI; F. MORETTO; A. LOPEZ; C. LOPEZ

Mineapolis, Minesota, USA

Congreso; Annual Meeting of ASAS ADSA; 2006

American Society of Animal Science

The objective of this experiment was to evaluate the effect of feedingan uniform mixed diet compared with feeding the same proportionof each ingredient of the balanced diet delivered in separated bunks.Thirty beef steers (Braford, Criollo, and Braford × Criollo; initialaverage liveweight = 260 ± 21 kg) were used in a 87-d fi nishing study.Treatments consisted of a uniform mixed concentrate diet (control)vs. the same ingredients offered separately in equal proportion of themixed ration (free-choice). Treatments were arranged in a completelyrandomised design (three pens/ treatment). Animals were fed daily adlibitum with the following proportion of feedstuffs, 75% whole corngrain, 10% whole cotton seed, and 15% grass hay (Setaria italica). Allsteers had ad libitum access to water and a mineral-salt. Final bodyweight did not differ between treatments (fi nal average liveweight =331 ± 28 kg; P = 0.78). Average daily gain was numerically superiorto the control, but did not differ between control vs. free-choice(847 vs. 800 g/d for control vs. free-choice respectively; SEM = 100g/d). Intra-pen variability for ADG was similar between control andfree-choice (P = 0.59). Dry matter intake did not differ between controland free-choice (average dry matter intake, 7.2 vs. 7.1 kg/d for controlvs. free-choice respectively, P = 0.99). Similarly feed to gain ratiowas not affected by treatments (feed: gain ratio, 8.47 vs. 8.96 kg ofDM/ kg of gain for control vs. free-choice respectively, P = 0.30). Theproportion of whole corn grain was similar between treatments (75.4vs. 74.2% for control vs. free-choice respectively, P = 0.39). However,steers in free-choice adjusted the proportion of ingredients selectinggrass hay (14.6% control vs. 19.4% free-choice; P < 0.01) and rejectingwhole cotton seed (10.0% control vs. 6.5% free-choice; P < 0.05). Inconclusion under the conditions of this trial, free-choice selection ofthe components of a mix ration did not improve feed intake, liveweightgain, and feed effi ciency with regard to a uniform mixed diet.