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Effects of diversity and spatial separation of pastures on milk yields, N partitioning, and methane emissions in dairy cows.

L. Carmona-Flores

Abstract:

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Effects of diversity and spatial separation of pastures on milk yields, N partitioning, and methane emissions in dairy cows.
L. Carmona-Flores*1, M. Bionaz1, T. Downing1, M. Sahin2, S. Ates1. 1Department of Animal and Rangeland Sciences, Oregon State University Corvallis, OR, 2Department of Crop and Soil Sciences, Oregon State University Corvallis, OR.

Diverse pastures containing multiple species help extend the grazing season and reduce the reliance on one or 2 species to meet all the nutritional requirements of livestock. Planting pasture species in spatially separated adjacent strips can potentially increase the dry matter intake (DMI) of high-quality forages leading to superior animal production. Thus, in the current study, combinations of simple and diverse pasture mixtures in mixed and spatially separated pasture strips were evaluated for their effects on feed intake, milk yield, N partitioning and methane emission of dairy cows. A 7.2-ha paddock was divided into 3 2.4-ha blocks to serve as replicates for the experiment. For the purpose, 36 mid-lactation Jersey cows were used in a randomized complete block design with 9 cows in each pasture (3 blocks each) as follow: 1)simple mixed (perennial ryegrass and white clover); 2)simple spatially separated; 3)diverse mixed (perennial ryegrass, festulolium, white clover, birdsfoot trefoil, plantain and chicory; 4)diverse spatially separated. Milk yield and quality, N partitioning, and methane emission were measured. Data were analyzed by ANOVA based on a 2 � 2 factorial model with significance declared at P ≤ 0.05. Cows that grazed diverse pastures had greater milk solids (2310 g/d; P = 0.05) and milk protein yields (883 g/d; P = 0.01) as compared with those that grazed simple pastures (2083 g/d and 778 g/d, respectively). Spatial separation did not affect DMI, milk yield, or milk components except lactose content of milk, which was lower (P = 0.01) in spatially separated pastures. Although pasture diversity did not affect daily methane production, cows that grazed diverse pastures had lower (P = 0.05) methane yields per DM eaten (18.8 g) as compared with simple pastures (22.3 g). Cows that grazed diverse pastures had lower (P = 0.01) urine N (%) (0.3%) and urea content (104.1 mmol/L) and lower daily N output through urine (144.2 g/d). In conclusion, the diverse pastures containing species with certain agronomic and nutritional traits such as secondary metabolites can help improve animal production while decreasing the environmental effect of dairy farming.

Keywords: species diversity, methane emissions, N partitioning.

Biography: My name is Lorena Fernanda Carmona Flores and I was born and raised in Santiago, Chile. Since I was a kid, I have always love animals, so my dream was to become a veterinarian. In 2008 I join to Universidad de Chile to study Doctor of Veterinary Medicine and in here I started to know different areas of specialization and a love appeared: the love for cows. Over time, my love for the cows extended also to the people who work with them. And that is how I ended up in the Animal Science industry.