title: Effects of Physically Effective Neutral Detergent Fiber Content on Intake, Digestibility, and Chewing Activity in Fattening Heifer Fed Total Mixed Ration.
abstract: The objective of this study was to determine the effects of physically effective neutral detergent fiber (peNDF) content in total mixed ration (TMR) on dry matter intake, digestibility, and chewing activity in fattening Hanwoo (Bos taurus coreanae) heifers. The experiment was designed as a replicated 3×3 Latin square using 12 heifers. Fattening heifers were offered one of three diets [high (T1), medium (T2), and low (T3) peNDF] obtained by different mixing times (3, 10, and 25 min) for the same TMR feed. The peNDF content of TMR was determined by multiplying the proportion of dry matter retained by a 1.18 mm-screen in a Penn State Particle Separator by the dietary NDF content. The peNDF1.18content was 30.36%, 29.20%, and 27.50% for the T1, T2, and T3 diets, respectively (p<0.05). Dry matter intake was not affected by peNDF content in TMR. Total weight gain in T1 group was significantly higher (p<0.05) than in T2 and T3 groups. However, weight gain did not differ between T2 and T3 groups. The feed conversion ratio decreased with an increase in the peNDF content (T1: 12.18, T2: 14.17, and T3: 14.01 g/g). An increase in the peNDF content of TMR was associated with a linear increase in the digestibility of dry matter, crude protein, crude fiber, neutral detergent fiber, and acid detergent fiber (p<0.05). Also, an increase in peNDF content of the TMR resulted in a linear increase in the number of chews in eating and ruminating (p<0.05), and consequently in the number of total chews (p<0.05). These results indicate that peNDF content affects digestibility and chewing activity. Consequently, the peNDF content of TMR should be considered for improving feed efficiency, digestibility, body weight gain, and performance in fattening heifers.
authors.affiliation: Korea Nokyong Research Center, Division of Food Bio Science, Konkuk University, Chungju 27478, Korea.
authors.forename: Mi Rae
authors.initials: MR
authors.lastname: Oh
authors.affiliation: Department of Medical Science, School of Medicine, Konkuk University, Seoul 05029, Korea.
authors.forename: Heeok
authors.initials: H
authors.lastname: Hong
authors.affiliation: Korea Nokyong Research Center, Division of Food Bio Science, Konkuk University, Chungju 27478, Korea.
authors.forename: Hong Liang
authors.initials: HL
authors.lastname: Li
authors.affiliation: Korea Nokyong Research Center, Division of Food Bio Science, Konkuk University, Chungju 27478, Korea.
authors.forename: Byong Tae
authors.initials: BT
authors.lastname: Jeon
authors.affiliation: Korea Nokyong Research Center, Division of Food Bio Science, Konkuk University, Chungju 27478, Korea.
authors.forename: Cheong Hee
authors.initials: CH
authors.lastname: Choi
authors.affiliation: Korea Nokyong Research Center, Division of Food Bio Science, Konkuk University, Chungju 27478, Korea.
authors.forename: Yu Ling
authors.initials: YL
authors.lastname: Ding
authors.affiliation: Korea Nokyong Research Center, Division of Food Bio Science, Konkuk University, Chungju 27478, Korea.
authors.forename: Yu Jiao
authors.initials: YJ
authors.lastname: Tang
authors.affiliation: Korea Nokyong Research Center, Division of Food Bio Science, Konkuk University, Chungju 27478, Korea.
authors.forename: Eun Kyung
authors.initials: EK
authors.lastname: Kim
authors.affiliation: Korea Nokyong Research Center, Division of Food Bio Science, Konkuk University, Chungju 27478, Korea.
authors.forename: Se Young
authors.initials: SY
authors.lastname: Jang
authors.affiliation: Korea Nokyong Research Center, Division of Food Bio Science, Konkuk University, Chungju 27478, Korea.
authors.forename: Hye Jin
authors.initials: HJ
authors.lastname: Seong
authors.affiliation: Korea Nokyong Research Center, Division of Food Bio Science, Konkuk University, Chungju 27478, Korea.
authors.forename: Sang Ho
authors.initials: SH
authors.lastname: Moon
keywords: Chewing Activity; Digestibility; Dry Matter Intake; Fattening Heifer; Physically Effective Neutral Detergent Fiber; Total Mixed Ration