title: Effect of ferric ammonium citrate in feedlot diets with varying dried distillers' grains inclusion on ruminal hydrogen sulfide concentrations and steer growth.
abstract: Angus-cross steers ( = 128) were used to examine the effects of supplementing ferric ammonium citrate (FAC; 300 mg ferric Fe/kg DM) to diets of 20, 40, or 60% dried distillers' grains plus solubles (DDGS) on growth performance, liver mineral and ruminal hydrogen sulfide (HS) concentrations, and carcass traits of finishing steers. Steers were blocked by initial BW (436 ± 10.6 kg) into pens of 4 and randomly assigned to 1 of 6 treatments ( = 5 or 6 pens per treatment) including a 20, 40, or 60% DDGS inclusion diet with (+) or without (-) 300 mg Fe/kg DM from FAC. Liver biopsies (d -9/-10 and 96) and HS measures (d 0, 7, 14, 21, and 95) were determined from 1 steer/pen. Steers were harvested on d 102 and carcass data were collected. A treatment × month effect ( ≤ 0.006) was noted for ADG and G:F, in which the 20-FAC ADG and feed efficiency were greater ( ≤ 0.02) between d 0 to 28 but lesser ( ≤ 0.04) from d 29 to 56 than that of the 20+FAC steers. Final BW linearly decreased ( < 0.01) as DDGS inclusion increased. Final BW tended to be greater ( = 0.10) in the 60+FAC steers than in the 60-FAC steers, whereas final BW was not different ( ≥ 0.32) due to FAC supplementation in the 20 or 40% DDGS diets. A quadratic effect was noted for DMI ( = 0.02), where 60% DDGS decreased DMI. Within the 20% DDGS diet FAC+ improved DMI ( = 0.03) but had no effect within 40 or 60% DDGS inclusion. Ruminal HS concentrations were not affected ( ≥ 0.25) by FAC, but increasing DDGS linearly increased ( < 0.01) ruminal HS values. Liver Cu was decreased ( < 0.01) by FAC across all DDGS inclusions and tended to linearly decrease ( = 0.06) with increasing DDGS inclusion, whereas liver Fe, Mn, and Zn were not altered ( ≥ 0.11) by DDGS inclusion. Liver Zn concentrations tended to be ( = 0.08) or were ( = 0.03) decreased by FAC supplementation within 20 and 40% DDGS, respectively. Increasing the inclusion of DDGS linearly decreased ( = 0.04) HCW and quadratically affected marbling score where the 40% DDGS had the greatest ( = 0.02) marbling scores. Supplementation of FAC within 60% DDGS improved ( ≤ 0.03) HCW and LM area. Marbling scores were greater ( ≤ 0.04) in 20+FAC and 40+FAC compared with 20-FAC and 40-FAC, respectively. In conclusion, although ruminal HS concentrations were not affected by FAC under the conditions of this study, supplementing FAC to diets containing 60% DDGS improved HCW and LM area, suggesting that FAC may be beneficial when dietary S concentrations exceed 0.5%.
authors.forename: D J
authors.initials: DJ
authors.lastname: Pogge
authors.forename: M E
authors.initials: ME
authors.lastname: Drewnoski
authors.forename: D
authors.initials: D
authors.lastname: Snider
authors.forename: W K
authors.initials: WK
authors.lastname: Rumbeiha
authors.forename: S L
authors.initials: SL
authors.lastname: Hansen
mesh_terms: D000821:Animal Feed / Q000032:analysis; D000818:Animals; D001835:Body Weight / Q000187:drug effects; D002417:Cattle / Q000254:growth & development / Q000502:physiology*; D004032:Diet / Q000662:veterinary; D019587:Dietary Supplements; D002523:Edible Grain; D005290:Ferric Compounds / Q000494:pharmacology*; D006862:Hydrogen Sulfide / Q000378:metabolism*; D008297:Male; D000644:Quaternary Ammonium Compounds / Q000494:pharmacology*; D012417:Rumen / Q000187:drug effects / Q000378:metabolism
chemical_list: D005290:Ferric Compounds; D000644:Quaternary Ammonium Compounds; C013531:ferric ammonium citrate; D006862:Hydrogen Sulfide