D W Beckman

Publications (4)4.19 Total impact

• Article: Inheritance of pulmonary arterial pressure in Angus cattle and its correlation with growth.

  K L Shirley, D W Beckman, D J Garrick
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  ABSTRACT: Pulmonary arterial pressure (PAP) is an indicator of resistance to blood flow through the lungs and when measured at high altitude is a reliable predictor of susceptibility of an animal to brisket disease, a noninfectious cardiac pulmonary condition. (Co)-variance components for PAP, birth weight, and adjusted 205-d weaning weight were estimated from 2,305 spring-born, registered Angus cattle from a Colorado ranch at an elevation of 1,981 m. A single measure of PAP was collected after weaning on animals born from 1984 to 2003. The same licensed veterinarian measured every animal. Multitrait animal models with and without PAP maternal effects were fitted for a pedigree including 132 sires and 793 dams. The interaction of year x sex was a significant fixed effect (P <0.05) for PAP, but age of dam was not. Age at PAP testing was a significant (P <0.1) linear covariate for PAP, and scores increased 0.012 +/- 0.007 mmHg X d(-1) of age. Heritability of PAP direct was 0.34 +/- 0.05. Maternal heritability converged to a boundary at 0.0, and the model with maternal genetic effects for PAP was not significantly better than a model with only direct effects. Phenotypically, PAP was uncorrelated with birth or weaning weights. Genetically, PAP appeared to have positive, unfavorable relationships with direct effects for birth (0.49 +/- 0.12) and weaning weight (0.50 +/- 0.18). Positive correlations imply sires whose offspring exhibited resistance to brisket disease had lower weights and gains. A model that evaluated PAP in females and males as different traits had heritability estimates for each sex of 0.38 +/- 0.07 and 0.46 +/- 0.09, respectively, with a genetic correlation of 0.64 +/- 0.12 between the sexes and was not significantly better than the model assuming homogeneity by sex and a unit genetic correlation between sexes. The results suggest that PAP is moderately heritable in spring-born Angus cattle acclimatized and tested at high altitude, and selection for low PAP scores would be effective. Selection for growth at low altitude will produce cattle less suited to high altitude.
  Journal of Animal Science 05/2008; 86(4):815-9. · 2.10 Impact Factor
• Article: Maternal effects on docility in Limousin cattle.

  D W Beckman, R M Enns, S E Speidel, B W Brigham, D J Garrick
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  ABSTRACT: The objective of this study was to quantify the role of maternal effects on docility in Limousin cattle. Docility scores were obtained at weaning while animals were restrained in a squeeze chute. Scores 1 through 6 represented a docile to aggressive temperament, respectively, and were provided by the North American Limousin Foundation. Observations with unknown age of dam, contemporary groups containing less than 10 observations, contemporary groups with no variation, and single-sire contemporary groups were removed, leaving 21,932 observations. A 2-generation pedigree file compiled from animals with observations contained 49,459 animals. Fixed effects were weaning contemporary group and age of dam (2, > or =3 yr). Six animal models encompassed combinations of random factors: direct genetic, maternal genetic, and maternal permanent environmental effects. The model D was the most basic, containing direct genetic and residual effects, and it resembled the method currently used by the North American Limousin Foundation for genetic evaluation of docility. Maternal genetic or permanent environmental effects were separately added to the model D, denoted as models DM and DC, respectively. Model DMC contained all random factors. Models DM-Zero and DMC-Zero were equivalent to models DM and DMC, respectively, but with zero direct-maternal genetic covariance. Direct heritability estimates were moderate for all models (0.29 +/- 0.02 to 0.38 +/- 0.03). Maternal heritability estimates were low, ranging from 0.01 +/- 0.01 (DM-Zero) to 0.05 +/- 0.02 (DM). Negative direct-maternal genetic correlations of -0.41 +/- 0.09 and -0.55 +/- 0.09 were estimated for models DM and DMC, respectively. The proportion of phenotypic variance accounted for by maternal permanent environmental effects was 0.03 +/- 0.01, 0.04 +/- 0.01, and 0.02 +/- 0.01 for models DC, DMC, and DMC-Zero, respectively. Likelihood ratio tests indicated that model DMC best fit the data. Although maternal genetic and maternal permanent environmental effects were significant, they accounted for only 8% (model DMC) of the phenotypic variance, and a Spearman rank correlation of 0.99 between models D and DMC showed sires did not rank differently with or without inclusion of these effects. Given these results, inclusion of maternal effects to the genetic evaluation of docility in Limousin cattle does not seem warranted.
  Journal of Animal Science 04/2007; 85(3):650-7. · 2.10 Impact Factor
• Article: Inheritance of pulmonary arterial pressure in Angus cattle and its correlation with growth1

  K. L. Shirley, D. W. Beckman, D. J. Garrick
  [show abstract] [hide abstract]
  ABSTRACT: Pulmonary arterial pressure (PAP) is an indicator of resistance to blood flow through the lungs and when measured at high altitude is a reliable predictor of susceptibility of an animal to brisket dis- ease, a noninfectious cardiac pulmonary condition. (Co)- variance components for PAP, birth weight, and ad- justed 205-d weaning weight were estimated from 2,305 spring-born, registered Angus cattle from a Colorado ranch at an elevation of 1,981 m. A single measure of PAP was collected after weaning on animals born from 1984 to 2003. The same licensed veterinarian measured every animal. Multitrait animal models with and with- out PAP maternal effects were fitted for a pedigree including 132 sires and 793 dams. The interaction of year × sex was a significant fixed effect (P < 0.05) for PAP, but age of dam was not. Age at PAP testing was a significant (P < 0.1) linear covariate for PAP, and scores increased 0.012 ± 0.007 mmHgd−1 of age. Herita- bility of PAP direct was 0.34 ± 0.05. Maternal heritabil- ity converged to a boundary at 0.0, and the model with
• Article: Heritability Estimates and Genetic Correlations for Stayability and Body Condition Score in Beef Females

  D. W. Beckman, S. E. Speidel, B. W. Brigham, D. J. Garrick, R. M. Enns