Effect of Diet Choices on Feed Consumption Behavior of Cattle

Abstract Text: Cattle are by nature discriminatory in their eating behavior, often selecting some plant species or parts of plants over others.  In feedlot production systems cattle typically are presented homogeneous diet mixtures, thus minimizing opportunity for them to make choices. We hypothesized that simultaneous presentation of two diets would lead to greater feed intakes for cattle fed in confinement.  Forty crossbred heifers (354±5.43 kg initial BW) were used in an experiment to test this hypothesis, and to determine if cattle exhibit preferences for total mixed diets made from sorghum or corn. Heifers were stratified by initial BW and randomly allocated, within strata, to one of 4 dietary treatments.  Cattle were individually housed in partially covered, concrete-surfaced pens (1.5 m x 6.5 m) and fed for a total of 21 d.  Treatments consisted of total mixed rations containing corn, sorghum, or a 50:50 mixture of corn and sorghum as the predominant energy source (CORN, SORGHUM, and MIX, respectively).  These were compared to a fourth treatment for which cattle were presented with ad libitum amounts of both CORN and SORGHUM (CHOICE).  Diets all contained 60% concentrate, 25% ground alfalfa hay, and 15% ground prairie hay. Grains were dry rolled to achieve a targeted mean geometric particle size of 1,000 μ.  Cattle were fed ad libitumonce daily at approximately 1730 h.   Orts were collected daily and a 10% sample was retained for determination of DM content, thus making it possible to calculate actual daily DMI for each animal. Of the 840 animal-days, cattle consumed 100% of their 24-h feed allocation in 64 instances, most of which occurred during the first week of the experiment. Dry matter intakes of cattle fed CHOICE (10.7 kg/d) were greater (P<0.05) than those of cattle fed other diets (9.3, 9.3, and 9.1 for CORN, SORGHUM, and MIX, respectively).  Differences among treatments with respect to ADG and gain efficiency were commensurate with changes in DMI, but were not significant (P > 0.24).  Over the 21-d feeding period, proportions of CORN and SORGHUM consumed by the CHOICE group were 55.9 and 44.1%, respectively. Cattle fed CHOICE exhibited preference for CORN on d 2, 14, 15, 16, 17, 18, 20, and 21 (P<0.05), but differences in proportions of the two diets consumed were not otherwise different.   Simultaneous presentation of dissimilar diets may increase feed intake of cattle fed in confinement.

Keywords: Feeding behavior, sorghum, corn