314 - Steer Production Performance and Enteric Gas Emissions Associated with Free-choice Mineral Supplement Infused with Varying Levels of Garlic Powder

Abstract: The addition of phytogenics such as garlic powder into beef mineral supplements is motivated by the potential for increased mineral intake and associated insectifugal outcomes. This 3-yr study compared feed and mineral intake and performance in crossbred beef steers that received free-choice mineral supplements infused with or without garlic powder (5% inclusion). The study design was a randomized complete block design where each steer (n=180) was randomly assigned to either a 5%GP or 0%GP treatment group, balancing for breed composition and initial body weight. Different garlic brands (5%GPLO, 5%GPSE, and 5%GPWL) were also assessed during the third year of study. Individual feed and mineral supplement intakes were monitored using automatic feeding units from different bunks ad libitum. Enteric gas fluxes (CH₄, CO₂, O_2, and H₂) were also measured with an automated head-chamber emission monitoring system. Over 3 yr, there was no difference (P > 0.05) in dry matter intake, average daily gain, and gain to feed ratio between 5%GP and 0%GP groups, but supplement intake was greater (P < 0.05) for 5%GP (206 gd^-1) compared with 0%GP (152 gd^-1) treatment. Comparing all brands in third year showed differences in mineral consumption where 5%GPLO (223 gd^-1) had greatest (P < 0.0001) supplement intake, but there was no difference (P > 0.05) among 5%GPSE (133 gd^-1), 5%GPWL (103 gd^-1) and 0%GP (145 gd^-1). Enteric gas fluxes did not differ between 5%GPLO and 0%GP for CH₄ (129 gd^-1, 119 gd^-1; P = 0.69), CO₂ (7912 gd^-1, 7351 gd^-1; P = 0.31), O₂ (5394 gd^-1, 4816 gd^-1; P = 0.15) and H₂ (0.84 gd^-1, 0.67 gd^-1; P = 0.42). Results suggest that infusing garlic at 5% increased supplement intake in feedlot cattle but had no effect on growth or enteric gas fluxes. Differences in the brands evaluated here may be related to the shelf/storage age of the products and the bioactive compound profiles.