Abstract
Brazilian milk production has significantly increased in the past decade; however, Brazil's absolute milk production is low as compared to the largest production countries. Grazing is a common characteristic of the many different dairy production systems implemented across Brazil. Therefore, the definition of adequate grazing strategies becomes essential. The adequate grazing strategy is the one that increases milk production in the long term, avoiding pasture degradation and promoting sustainable milk production. Environmental protection is inseparable from dairy production in the current context of climate change and global warming. The main environmental concern associated to dairy production is the production, and emission, of enteric methane (CH4). The grazing strategy implemented affects sward structure, and consequently, dry matter accumulation, forage chemical composition, animal performance, and enteric CH4 emissions. This study will evaluate the effects of two levels of grazing strategies on animal performance, milk production and mitigation of enteric CH4 emissions. In the first step, we will evaluate the effects of grazing swards with 95% of light interception (LI) versus maximum IL on animal performance, milk production, milk composition and enteric CH4 emissions. The second step represents a refinement of the first one, once the ideal point of herbage allowance has been identified, the effects of time of grazing rotation (morning versus afternoon) on animal performance, milk production, milk composition and enteric CH4 emissions will be evaluated. With this study, we expect to identify grazing strategies that allow for high quality milk sustainable production, with no addition of production cost.
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