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Estimates of correlations among yield traits and somatic cell score with different models to adjust for bovine somatotropin effects on Holstein dairy cows
Al-Seaf, A; Keown, J. F; Van Vleck, L. D.
  • Al-Seaf, A; University of Nebraska. Department of Animal Science. Lincoln. US
  • Keown, J. F; University of Nebraska. Department of Animal Science. Lincoln. US
  • Van Vleck, L. D; Roman L. Hruska U.S. Meat Animal Research Center. Lincoln. US
Genet. mol. res. (Online) ; 6(1): 67-78, 2007. tab
Article in English | LILACS | ID: lil-456752
ABSTRACT
Records of Holstein cows from the Dairy Records Processing Center at Raleigh, NC were edited to obtain three data sets 65,720 first, 50,694 second, and 65,445 later lactations. Correlations among yield traits and somatic cell score were estimated with three different models 1) bovine somatotropin (bST) administration ignored, 2) bST administration as a fixed effect and 3) administration of bST as part of the contemporary group (herd-year-month-bST). Heritability estimates ranged from 0.13 to 0.17 for milk, 0.12 to 0.20 for fat, 0.14 to 0.16 for protein yields, and 0.08 to 0.09 for somatic cell score. Estimates were less for later than first lactations. Estimates of genetic correlations among yields ranged from 0.35 to 0.85 with no important differences between estimates with the 3 models. Estimates for lactation 2 agreed with estimates for lactation 1. Estimates of genetic correlations for later lactations were generally greater than for lactations 1 and 2 except between milk and protein yields. Estimates of genetic correlations between yields and somatic cell score were mostly negative or small (-0.45 to 0.11). Estimates of environmental correlations among yield traits were similar with all models (0.77 to 0.97). Estimates of environmental correlations between yields and somatic cell score were negative (-0.22 to -0.14). Estimates of phenotypic correlations among yield traits ranged from 0.70 to 0.95. Estimates of phenotypic correlations between yields and somatic cell score were small and negative. For all three data sets and all traits, no important differences in estimates of genetic parameters were found for the two models that adjusted for bST and the model that did not
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Full text: Available Index: LILACS (Americas) Main subject: Lactation / Cattle / Growth Hormone / Quantitative Trait, Heritable Type of study: Diagnostic study / Prognostic study Limits: Animals Language: English Journal: Genet. mol. res. (Online) Journal subject: Molecular Biology / Genetics Year: 2007 Type: Article Affiliation country: United States Institution/Affiliation country: Roman L. Hruska U.S. Meat Animal Research Center/US / University of Nebraska/US

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Full text: Available Index: LILACS (Americas) Main subject: Lactation / Cattle / Growth Hormone / Quantitative Trait, Heritable Type of study: Diagnostic study / Prognostic study Limits: Animals Language: English Journal: Genet. mol. res. (Online) Journal subject: Molecular Biology / Genetics Year: 2007 Type: Article Affiliation country: United States Institution/Affiliation country: Roman L. Hruska U.S. Meat Animal Research Center/US / University of Nebraska/US