Authors : R.A. Ware , G.E. Arellano , A. Plascencia and R.A. Zinn
Abstract: Twelve lactating Holstein cows (578 kg) were used in a replicated 3x3 Latin square design. Treatments consisted of steam-flaked corn-based lactation diets containing (DMB): 1) 50% alfalfa hay; 2) 39% alfalfa hay, 8% ground rice straw; and 3) 39% alfalfa hay, 8% macerated rice straw. Diets were formulated to contain 20% forage NDF (DMB). Rice straw treatments provided 24% of the total forage NDF. Alfalfa hay and rice straw treatments were ground to pass through a 7.6 and 2.6 cm screen, respectively, before incorporation into complete mixed diets. Dry matter intake was lower (5%; p<0.05) for alfalfa as the sole forage (ALF) than for the rice straw supplemented diets. Live weight gain was greater (155%, p<0.05) for rice straw supplemented diets than for ALF. Live weight gain was greater (14%, p<0.05) for macerated rice straw (RSM) than for the ground rice straw supplemented diet (RSG). There were no treatment effects (p>0.10) milk yield and milk SNF percentage. However, milk fat and protein percentages were greater (5 and 4%, respectively, p<0.05) for the RSM than for ALF and RSG. Milk lactose concentration was greater (5%, p<0.05) for RSG than for RSM. Although the expected NE content of the basal alfalfa diet (based on tabular values; NRC, 2001) was only L slightly (1.6%) greater than that of the rice straw supplemented diets, the observed dietary NE was lower (8%, L p<0.05) and observed vs expected DMI intake was greater (12%, p<0.05) for ALF than for RSG and RSM. We conclude that rice straw may replace 24% of the forage NDF provided by alfalfa hay in lactation diets without detrimentally affecting energy intake and fat corrected milk yield. Maceration of rice straw may enhance milk fat and milk protein concentration compared with that of ground rice straw and/or alfalfa hay.
R.A. Ware , G.E. Arellano , A. Plascencia and R.A. Zinn , 2005. Influence of Partial Substitution of Alfalfa Hay with Ground Versus Macerated Rice Straw on Dry Matter Intake and Performace of Lactating Holstein Cows . Journal of Animal and Veterinary Advances, 4: 694-697.