Relationships between feed efficiency, scrotal circumference, and semen quality traits in yearling bulls

Relationships between feed efficiency, scrotal circumference, and semen quality traits in yearling bulls A. N. Hafla, P. A. Lancaster, G. E. Carstens, D. W. Forrest, J. T. Fox, T. D. A. Forbes, M. E. Davis, R. D. Randel and J. W. Holloway J ANIM SCI 2012, 90:3937-3944. doi: 10.2527/jas.2011-4029 originally published online June 4, 2012

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Relationships between feed efficiency, scrotal circumference, and semen quality traits in yearling bulls
A. N. Hafla,* P. A. Lancaster,† G. E. Carstens,*1 D. W. Forrest,* J. T. Fox,‡ T. D. A. Forbes,§ M. E. Davis,# R. D. Randel,║ and J. W. Holloway§
*Department of Animal Science, Texas A&M University, College Station 77843;†Department of Animal Science, Oklahoma State University, Stillwater 74078; ‡JBS Five Rivers Cattle Feeding LLC, Greeley, CO 80634; §Texas AgriLife Research, Uvalde 78801;# Department of Animal Sciences, Ohio State University, Columbus 43210; and ║Texas AgriLife Research, Overton 75684

ABSTRACT: A meta-analysis was conducted to examine phenotypic relationships between feed efficiency, scrotal circumference, and semen quality traits in yearling bulls. Data evaluated were obtained from 5 postweaning trials involving Angus (n = 92), Bonsmara (n = 62), and Santa Gertrudis (n = 50) bulls fed diets that ranged from 1.70 to 2.85 Mcal ME/kg DM. After an adaptation period of 24 to 28 d, feed intake was measured daily, and BW was measured at 7- or 14-d intervals during the 70- to 77-d trials. Ultrasound carcass traits (12th-rib back fat thickness, BF; LM area, LMA) and scrotal circumference (SC) were measured at the start and end of each trial. Semen samples were collected by electroejaculation within 51 d of the end of the trials when the