|Brown, jr., A|
Submitted to: Journal of Animal Science
Publication Type: Abstract only
Publication Acceptance Date: 9/30/1999
Publication Date: N/A
Citation: BROWN, M.A., BROWN, JR., A.H., JACKSON, W.G., MIESNER, J.R. GENOTYPE X ENVIRONMENT INTERACTIONS IN MILK YIELD AND QUALITY IN ANGUS, BRAHMAN, AND RECIPROCAL-CROSS COWS ON DIFFERENT FORAGE SYSTEMS. JOURNAL OF ANIMAL SCIENCE. 1999. v.78(3). p.546-551. Interpretive Summary: Abstract Only.
Technical Abstract: Milk yield and quality were observed on 93 Angus, Brahman, and reciprocal-cross cows over three years to evaluate the interactions of direct and maternal breed effects and heterosis with forage environment. Forage environments were common bermudagrass (BG), endophyte-infected tall fescue (E+), and a rotational system of both forages where each forage (BG or E+) was grazed at appropriate times of the year (ROT). Milk yield (MY) was estimated each of six months (April-September) by method of milking machine and converted to a 24-h basis. Milk fat (MF), milk protein (PRO), and somatic cell count (SCC) were measured by a commercial laboratory. The natural log of SCC was used for analyses. Heterosis for 24-h MY was large and similar among forages, averaging 2.4 kg (P<.01). There was little evidence of maternal effects for MY for any forage. Direct effects for MY were similar among forages and averaged 2.20 kg in favor of Brahman (P<.10). There was little evidence of heterosis or maternal breed effects for MF. Direct breed effects for MF were similar across forages and averaged .86% in favor of Brahman (P<.01). There was little evidence of direct or maternal breed effects for PRO nor was there evidence of forage effects for this trait. Purebred cows exceeded crossbreds in PRO by .13% on ROT (P<.10). Crossbred cows had lower SCC than purebreds on E+ (P<.10) but heterosis on BG and ROT was not significant. Maternal breed effects for SCC were similar among forages and favored the Brahman dam (P<.10). Direct breed effects for SCC were small and unimportant. These results suggest that direct and maternal breed effects and heterosis for milk yield and quality were relatively stable across the forage systems evaluated.