| Autor: |
Sandelin, B.A., Brown Jr., A.H., Brown, M.A., Johnson, Z.B., Kellog, D.W., Stelzleni, A.M. |
| Předmět: |
|
| Zdroj: |
Journal of Animal Science; Dec2002, Vol. 80 Issue 12, p3073, 4p, 2 Charts, 1 Graph |
| Abstrakt: |
Mature weight and rate of maturing were estimated in 177 Angus, Brahman, and reciprocalcross cows grazing bermudagrass or endophyte-infected tall fescue over a 4-yr period to evaluate genotype × environment interactions. Data were collected every 28 d until cows were approximately 18 mo of age and then at prebreeding, postcalving, and weaning of call All cows with weight data to at least 42 mo of age were included in the analysis. Mature weight and rate of maturing were estimated using the three-parameter growth curve model described by Brody (1945). Data were pooled over year and analyzed by the general linear model procedure of SAS. Included in the models for mature weight and rate of maturing were the independent variables of genotype, environment, and genotype × environment interaction. There was a genotype × environment interaction (P < 0.01) for mature body weight (BW) but not for rate of maturing. Angus cows grazing fescue pastures had greater (P < 0.01) mean mature BW than Angus × Brahman cows grazing bermudagrass (611 ± 17 vs 546 ± 16 kg). Angus × Brahman cows grazing bermudagrass had lower (P < 0.05) mean mature BW than Brahman × Angus cows grazing bermudagrass or endophyte-infected fescue and Brahman cows grazing bermudagrass (546 ± 16 vs 624 ± 19, 614 ± 22 and 598 ± 20 kg, respectively). Brahman cows grazing endophyte-infected rescue had smaller (P < 0.05) mean mature BW than all genotype × forage combinations except for Angus x Brahman cows grazing bermudagrass. Angus cows had a smaller (P < 0.05) mean rate of maturing than Angus x Brahman and Brahman x Angus cows (0.039 ± 0.002 vs 0.054 ± 0.002 and 0.049 ± 0.002%/mo, respectively), respectively, and Angus x Brahman cows had a larger (P < 0.05) mean rate of maturing than Brahman x Angus and Brahman cows (0.054 ± 0.002 vs 0.049 ± 0.002 and 0.041 ± 0.002 %/mo, respectively).... [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
|
