[Download] "Effects of Selection for Blood Serum Insulin-Like Growth Factor I Concentration on Reproductive Performance of Female Angus Beef Cattle" by Xinyue Zhang * eBook PDF Kindle ePub Free
eBook details
- Title: Effects of Selection for Blood Serum Insulin-Like Growth Factor I Concentration on Reproductive Performance of Female Angus Beef Cattle
- Author : Xinyue Zhang
- Release Date : January 19, 2013
- Genre: Computers,Books,Computers & Internet,
- Pages : * pages
- Size : 7642 KB
Description
Reproductive performance of animals affects lifetime productivity. However improvement of reproductive traits via direct selection is generally slow due to low heritability. Therefore, identification of indicator traits for reproductive performance may enhance genetic response. Previous studies showed that serum insulin-like growth factor I (IGF-I) concentration is a candidate indicator for growth and reproductive traits. The objectives of our study were to estimate the (co)variances for IGF-I concentration and reproductive, body composition, and growth traits. Data were collected from a divergent selection experiment for serum IGF-I concentration at the Eastern Agricultural Research Station owned by The Ohio State University. The study included a total of 2,662 calves in the 1989 to 2005 calf crops. (Co)variance components were estimated for genetic effects, maternal environment effects, environment effects, and phenotypic effects using an animal model in multiple-trait, derivative-free, restricted maximum likelihood for and ASReml computer programs. The results of direct additive genetic correlation suggest that selection for greater IGF-I concentration (heritability = 0.50 ± 0.07) could lead to increased conception (heritability = 0.11± 0.06, r = 0.32, P < 0.001) and calving rate (heritability = 0.13 ± 0.06, r = 0.43, P < 0.001), increased d 140 postweaning ribeye area (heritability = 0.63 ± 0.08, r = 0.38, P < 0.001) and weight (heritability = 0.62 ± 0.08, r = 0.15, P < 0.001), and decreased age at first calving in heifers (heritability = 0.35 ± 0.20, r = -0.40, P < 0.001). Advisors/Committee Members: Davis, Michael.
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