Comparison of selection by independent culling levels for below-average birth weight and high yearling weight with mass selection for high yearling weight in line 1 Hereford cattle

• Published in: Journal of animal science Vol. 76; no. 2; pp. 458 - 467
• Main Authors: MacNeil, M.D. (USDA, Miles City, MT.), Urick, J.J, Snelling, W.M
• Format: Journal Article
• Language: English
• Published: Savoy, IL Am Soc Animal Sci 01-02-1998; American Society of Animal Science; Oxford University Press
• Subjects: Aging; Analysis of Variance; Animal productions; Animals; Animals, Newborn; BEEF CATTLE; Biological and medical sciences; BIOLOGICAL DIFFERENCES; BIRTH WEIGHT; BODY WEIGHT; Breeding - methods; Breeding of animals; BREEDING VALUE; Cattle; Cattle - anatomy & histology; Cattle - genetics; Classical genetics, quantitative genetics, hybrids; CORRELATED TRAITS; CULLING; Female; Fertility; Fundamental and applied biological sciences. Psychology; GENETICS; Genetics of eukaryotes. Biological and molecular evolution; Genomic Imprinting; Inbreeding; LINE DIFFERENCES; Male; Montana; PARTURITION; SELECTION CRITERIA; SELECTION RESPONSES; Terrestrial animal productions; TRENDS; Vertebrata; Vertebrates; Weight; Montana; Genetic selection; Ox; Calving; Mass selection; Vertebrata; Mammalia; Beef cattle; Heifer; Birth weight; Artiodactyla; Animal production; Breeding value; Ungulata
• ISSN: 0021-8812; 1525-3163; 0021-8812
• DOI: 10.2527/1998.762458x

Mass selection by independent culling levels (YB subline) for below-average birth weight (BWT) and high yearling weight (YWT) was compared with single-trait mass selection (YW subline) for high YWT in the inbred population of Line 1 Hereford cattle at Miles City, Montana. There were 4.2 generations of selection in YB and YW. Heritability estimates for the base population derived from multiple-trait REML were .28 and .31 for direct effects and .16 and .06 for maternal effects on BWT and YWT, respectively. Mid-parent cumulative selection differentials for BWT of YB and YW diverged (-2.9 vs 8.2 kg, respectively), as did the associated genetic trends for direct effects (-.014 kg/yr vs .105 kg/yr, respectively). Mid-parent cumulative selection differential for YWT of YB (102.1 kg) was 64% of that attained in YW (160.7 kg). Likewise, response in YWT of YB (.91 kg/yr) was 61% of response attained in YW (1.5 kg/yr). For BWT and YWT, maternal genetic trends were similar across selection lines. Assistance at parturition of first-parity 2-yr-old heifers was consistently less frequent in YB than in YW