title: The influence of feed energy density and a formulated additive on rumen and rectal temperature in hanwoo steers.
abstract: The present study investigated the optimum blending condition of protected fat, choline and yeast culture for lowering of rumen temperature. The Box Benken experimental design, a fractional factorial arrangement, and response surface methodology were employed. The optimum blending condition was determined using the rumen simulated in vitro fermentation. An additive formulated on the optimum condition contained 50% of protected fat, 25% of yeast culture, 5% of choline, 7% of organic zinc, 6.5% of cinnamon, and 6.5% of stevioside. The feed additive was supplemented at a rate of 0.1% of diet (orchard grass:concentrate, 3:7) and compared with a control which had no additive. The treatment resulted in lower volatile fatty acid (VFA) concentration and biogas than the control. To investigate the effect of the optimized additive and feed energy levels on rumen and rectal temperatures, four rumen cannulated Hanwoo (Korean native beef breed) steers were in a 4×4 Latin square design. Energy levels were varied to low and high by altering the ratio of forage to concentrate in diet: low energy (6:4) and high energy (4:6). The additive was added at a rate of 0.1% of the diet. The following parameters were measured; feed intake, rumen and rectal temperatures, ruminal pH and VFA concentration. This study was conducted in an environmentally controlled house with temperature set at 30°C and relative humidity levels of 70%. Steers were housed individually in raised crates to facilitate collection of urine and feces. The adaptation period was for 14 days, 2 days for sampling and 7 days for resting the animals. The additive significantly reduced both rumen (p<0.01) and rectal temperatures (p<0.001) without depressed feed intake. There were interactions (p<0.01) between energy level and additive on ruminal temperature. Neither additive nor energy level had an effect on total VFA concentration. The additive however, significantly increased (p<0.01) propionate and subsequently had lower acetate:propionate (A/P) ratios than non-additive supplementation. High concentrate diets had significantly lower pH. Interactions between energy and additive were observed (p<0.01) in ammonia nitrogen production. Supplementation of diets with the additive resulted in lower rumen and rectal temperatures, hence the additive showed promise in alleviating undesirable effects of heat stress in cattle.
authors.affiliation: Department of Animal Science, Chonbuk National University, Jeonju 561-756, Korea ; Animal Resources Research Center, Konkuk University, Seoul 143-701, Korea .
authors.forename: Sangbuem
authors.initials: S
authors.lastname: Cho
authors.affiliation: Department of Animal Science, Chonbuk National University, Jeonju 561-756, Korea.
authors.forename: David Tinotenda
authors.initials: DT
authors.lastname: Mbiriri
authors.affiliation: Department of Animal Biotechnology, Chonbuk National University, Jeonju 561-756, Korea .
authors.forename: Kwanseob
authors.initials: K
authors.lastname: Shim
authors.affiliation: Department of Animal Science, Chonbuk National University, Jeonju 561-756, Korea.
authors.forename: A-Leum
authors.initials: AL
authors.lastname: Lee
authors.affiliation: Department of Animal Science, Chonbuk National University, Jeonju 561-756, Korea.
authors.forename: Seong-Jin
authors.initials: SJ
authors.lastname: Oh
authors.affiliation: Department of Animal Science, Chonbuk National University, Jeonju 561-756, Korea.
authors.forename: Jinho
authors.initials: J
authors.lastname: Yang
authors.affiliation: Department of Animal Science, Chonbuk National University, Jeonju 561-756, Korea.
authors.forename: Chaehwa
authors.initials: C
authors.lastname: Ryu
authors.affiliation: Department of Animal Science, Chonbuk National University, Jeonju 561-756, Korea.
authors.forename: Young-Hoon
authors.initials: YH
authors.lastname: Kim
authors.affiliation: Department of Animal Science and Technology, Sunchon National University, Suncheon 540-742, Korea .
authors.forename: Kang-Seok
authors.initials: KS
authors.lastname: Seo
authors.affiliation: Department of Dental Pharmacology, Chonbuk National University, Jeonju 561-756, Korea .
authors.forename: Jung-Il
authors.initials: JI
authors.lastname: Chae
authors.affiliation: Animal Nutrition and Physiology Division, National Institute of Animal Science, RDA, Suwon 441-706, Korea .
authors.forename: Young Kyoon
authors.initials: YK
authors.lastname: Oh
authors.affiliation: Department of Animal Science, Chonbuk National University, Jeonju 561-756, Korea.
authors.forename: Nag-Jin
authors.initials: NJ
authors.lastname: Choi
keywords: Beef Cattle; Feed Additive; Heat Stress; Rectal Temperature; Rumen Temperature