| Autor: |
Hernández LHV; Department of Animal Science, Autonomous University of Chapingo, Texcoco 56230, Mexico., Hernández AX; Graduate Programs in Animal Health and Production, College of Veterinary Medicine and Animal Science, National Autonomous University of Mexico, Mexico City 04510, Mexico., Gallegos EC; Center for Teaching, Research and Extension in Tropical Livestock, College of Veterinary Medicine and Animal Science, National Autonomous University of Mexico, Mexico City 04510, Mexico., Gonzalez-Ronquillo M; Department of Animal Nutrition, College of Veterinary Medicine and Animal Science, Autonomous University of Mexico State, Toluca 50000, Mexico., Vargas-Bello-Pérez E; Department of Animal Sciences, School of Agriculture, Policy and Development, University of Reading, P.O. Box 237, Earley Gate, Reading RG6 6EU, UK., Corona L; Department of Animal Nutrition and Biochemistry, College of Veterinary Medicine and Animal Science, National Autonomous University of Mexico, Mexico City 04510, Mexico. |
| Abstrakt: |
The objective of this study was to determine milk fatty acids from crossbred F1 dairy cows fed on tropical grasses and supplemented with different levels of concentrate. Twelve dairy cows (50% Holstein × 50% Brahman) with 60 days of lactation grazing tropical grasses were assigned to a Switchback design, with three periods of 15 days with different concentrate levels: 0, 150, 300 and 450 g /kg. Milk samples were obtained on the last five days of each experimental period. Milk yield and milk composition were not affected. Cows fed with 300 g/kg of concentrate had higher contents of C15:0 ( p = 0.004), C22:0 ( p = 0.031), and C24:0 ( p = 0.013). C17:1 cis9 was higher ( p = 0.039) with 150 g/kg and lowest with 450 g/kg. C18:1 cis9 was higher ( p = 0.042) with 150 g/kg. C18:2n6trans was higher ( p = 0.05) with 300 g/kg and lower ( p = 0.018) with 450 g/kg. This study shows that adding up to 450 g/kg of concentrate to crossbred F1 dairy cows fed on tropical grasses does not have negative effects on milk yield and milk quality. Therefore, under these production conditions, farmers can rely on tropical grasses and reduce feeding costs. |
