Abstract
The objective of this project is to evaluate the effects of corn grain processing methods (i.e. flaking, fine and coarse ground, and reconstitution) on milk production and metabolism variables of cows grazing Elephant grass (Pennisetum purpureum cv. Cameron) during the rainy season. In the first experiment, 12 Holstein x Jersey crossbred cows will be used in a Latin square design. The treatments will be: T1- Control- 8 Kg/cow/day of coarse ground corn; T2- 8 Kg/cow/day of fine ground corn; T3-8 Kg/cow/day of flaked corn grain; T4- 8 Kg/cow/day of reconstituted corn grain. The evaluated parameters will be: 1) production and composition (fat, protein, lactose, total solids, SCC, urea nitrogen and casein) of milk, 2) fatty acid profile, 3) blood variables, 4) purine derivatives; 5) Total and pasture dry matter intake and digestibility 6) Morphological and chemical compositions of pasture , 7)diet chemical composition 8) Body weight (BW) and condition of animals; 9) production efficiency 10) ingestive behavior . In experiment II, four rumen cannulated cows will be used in a Latin square design. The treatments will be: ; T1- Control- 8 Kg/cow/day of coarse ground corn T2- 8 Kg/cow/day of fine ground corn; T3- 8 Kg/cow/day of flaked corn grain; T4- 8 Kg/cow/day of reconstituted corn grain. The parameters studied will be: 1) intake and digestibility, 2) ruminal pH, volatile fatty acids, ammonia-N and microbial protein synthesis, 3) ruminal kinetics, 4) blood variables (i.e. non-esterified fatty acids, glucose, insulin and plasma urea N) 5) Methane emission. The statistical analyses will be done usingREG, MIXED and NLIN procedures of SAS package (2002).
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