Location: Forage and Livestock Production ResearchTitle: Milk yield and quality in cows sired by different beef breeds Author
Submitted to: Professional Animal Scientist
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/20/2010
Publication Date: 8/1/2010
Citation: Brown, M.A., Lalman, D.L. 2010. Milk yield and quality in cows sired by different beef breeds. Professional Animal Scientist. 26:393-397. Interpretive Summary: Higher genetic potential for milk yield is positively related to calf weaning weights but is unfavorably related to cow efficiency. Research at the USDA-ARS, Grazinglands Research Laboratory evaluated milk yield and quality from cows sired by Bonsmara, Brangus, Charolais, Gelbvieh, Hereford, and Romosinuano breeds. The only difference in milk yields noted were in Romosinuano-sired cows that were lesser than the other breed groups. The lack of differences among the Bonsmara, Brangus, Charolais, Hereford, and Gelbvieh-sired cows may be attributable to nutritional limitations on grazing native tallgrass prairie that impeded the expression of genetic potential for milk yield. If higher potential for milk yield is unfavorably associated with efficiency of production, efficiencies may be further impeded through failure of these breed groups to be allowed full expression of calf growth during the preweaning period through nutritional limitations. Consequently, it is important that genetic potential for milk yield in the cow be appropriate matched with nutritional environment.
Technical Abstract: Breed differences in milk production and quality are related to differences in calf preweaning growth, differences in cow maintenance requirements, and differences in efficiency of production. Cows from Brangus dams and sired by 12 Bonsmara, 12 Brangus, 15 Charolais, 18 Gelvieh, 13 Hereford, and 13 Romosinuano sires were sampled in 2005 (n=45), 2006 (n=50), 2007 (n=53) and 2008 (n=50) to evaluate sire breed differences in milk yield and quality. There was little evidence of daily milk yield differences among cows sired by Bonsmara, Brangus, Charolais, Gelbvieh, or Hereford sires, but Romosinuano-sired cows were lesser (P < 0.05) than the other breed groups. Gelbvieh-sired cows were lesser in percent milk fat than Bonsmara, Charolais, Hereford, and Romosinuano-sired cows (P < 0.05) but not Brangus-sired cows. Percent milk protein was greater in Romosinuano-sired cows than Brangus, Charolais, Gelbvieh, and Hereford-sired cows (P < 0.05) while percent milk protein was greater in Bonsmara-sired cows than Charolais and Gelbvieh-sired cows (P < 0.05). Percent milk lactose was similar for Bonsmara and Romosinuano-sired cows, which were both greater than Hereford-sired cows (P < 0.05). Somatic cell counts for Romosinuano-sired cows were lesser than those of Bonsmara, Charolais, Gelbvieh, and Hereford-sired cows (P < 0.05) but not Brangus. The lack of differences in milk yield among the sire breeds, with the exception of Romosinuano, suggest possible nutritional limitations on native rangeland that prevent expression of genetic potential for milk yield. The lower milk yields and somatic cell counts in the Romosinuano suggest possible advantages for this breed in efficiency of production and mastitis resistance. Key words: Beef cattle, tropically adapted, Bonsmara, Romosinuano, Brangus, Milk yield