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Effects of Divergent Selection for Insulin-like Growth Factor I (IGF-I) on Mature Weight and Growth Curves in Angus Cattle

Qin, Qing
http://rave.ohiolink.edu/etdc/view?acc_num=osu1275352602

Abstract Details

2010, Master of Science, Ohio State University, Animal Sciences.
The purpose of this study was to investigate the effect of divergent selection for serum insulin-like growth factor I (IGF-I) concentration on mature weight estimated using growth curve functions in Angus cattle. Multiple serum IGF-I measurements (d 28, d 42, d 56 of the 140-d postweaning period and the average of these 3, mean IGF) from a total of 2,514 animals and weight records from birth to at least 3 yr of age from a total of 172 animals were collected from an ongoing divergent selection experiment involving IGF-I that was initiated in 1989. Four growth curve functions (Brody, Logistic, Gompertz, Von Bertalanffy) were used to estimate the parameters for mature weight (A) and maturing rate (k) using the NLIN procedure in SAS (SAS Inst. Inc., Cary, NC). Based on the criteria of R2, MSE, AIC, and Log Likelihood, the Brody function fitted the weight-age data best, followed by the Von Bertalanffy function. The heritability estimates for serum IGF-I concentration at different ages and growth curve parameters from each function were obtained using a multiple-trait, derivative-free, REML program (MTDFREML). Genetic, environmental, and phenotypic correlations between mean IGF-I and growth curve parameters A and k were also obtained. The direct heritability (h2) estimates for serum IGF-I at d 28, 42, and 56 of the postweaning test were 0.42, 0.42, and 0.33, respectively. The h2 estimates for A from the 4 growth functions ranged from 0.77 to 1.00 in single-trait analyses. In 2-trait analyses, however, such estimates ranged from 0.26 to 0.41. The h2 estimates for k ranged from 0.12 to 0.33 in single-trait analyses, which were consistent with the results from the 2-trait analyses. The genetic correlations between mean IGF-I and A within each growth curve function ranged from -0.38 to -0.06. Although serum IGF-I was negatively genetically correlated with mature weight, the phenotypic correlation between these 2 traits was moderate (from 0.50 to 0.59) due to highly positive environmental correlations (mostly converged to 1.00). The growth curves for the low IGF-I selection line were exceeded the growth curves for the high IGF-I selection line in weight with an average difference of 10 kg after approximately 3 yr of age. This result suggests that selection for IGF-I may affect mature weight in Angus cattle and that the cows from the high IGF-I selection line may be more economical due to lighter mature weights and thus lower maintenance requirements.
Michael Davis, Phd (Advisor)
Steven Moeller, PhD (Committee Member)
Thomas Turner, PhD (Committee Member)
86 p.
Animals
IGF-I; growth curve; mature weight

Recommended Citations

Citations

  • Qin, Q. (2010). Effects of Divergent Selection for Insulin-like Growth Factor I (IGF-I) on Mature Weight and Growth Curves in Angus Cattle [Master's thesis, Ohio State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=osu1275352602

    APA Style (7th edition)

  • Qin, Qing. Effects of Divergent Selection for Insulin-like Growth Factor I (IGF-I) on Mature Weight and Growth Curves in Angus Cattle. 2010. Ohio State University, Master's thesis. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=osu1275352602.

    MLA Style (8th edition)

  • Qin, Qing. "Effects of Divergent Selection for Insulin-like Growth Factor I (IGF-I) on Mature Weight and Growth Curves in Angus Cattle." Master's thesis, Ohio State University, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=osu1275352602

    Chicago Manual of Style (17th edition)

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This open access ETD is published by The Ohio State University and OhioLINK.