Suchergebnisse

<p>We evaluated the physicochemical composition and fatty acid profile of milk from F1 Holstein <strong>× </strong>Zebu cows that were fed increasing levels of urea (0%, 33%, 66% and 100%, corresponding to 0%, 0.92%, 1.84% and 2.77% CP as NPN) as a substitute for soybean meal. Eight lactating F1 Holstein <strong>× </strong>Zebu cows producing an average of 10 kg of milk per day corrected to 3.5% fat, were placed in two 4 <strong>× </strong>4 Latin squares (4 animals, 4 diets and 4 periods). Each experimental period lasted 18 days. Milk samples from each cow were collected from morning and afternoon milkings and analyzed for composition and fatty acid concentration. Milk urea nitrogen increased linearly (P &lt; 0.05) with increasing dietary urea. Other variables including fat content, protein, fixed mineral residues, lactose, total nonfat solids, acidity, density, casein, cryoscopic index, somatic cell count, and milk fatty acid concentrations, were not affected by treatment. Thus, urea provides a viable alternative to soybean meal that does not affect the characteristics of milk from primiparous F1 Holstein <strong>× </strong>Zebu cows, producing up to 10 kg of milk corrected to 3.5% fat day-1.</p>

The objective was to evaluate the rumen degradability of dry matter, crude protein and fiber fraction of some oilseed byproducts. Oilseed byproducts evaluated were: Sunflower Meal, Cotton Cake and Castor Bean Cake. The rumen degradability test was performed following a split plot randomized complete block design with three treatments (plots) and seven incubation times (subplots) and six blocks (animals). The readily soluble fraction of the dry matter of sunflower meal was 35.0% higher than the same fraction of cotton cake and castor bean cake (mean 24.46%, P < 0.01). The highest potential degradability of crude protein (P < 0.01) was verified in castor bean cake (96.90%, 5% rate of passage). Sunflower meal had the lowest insoluble fraction of the fiber fraction, 34.4%, compared to cotton cake and castor bean cake, with 64.4% and 39.4%, respectively (P < 0.01). Sunflower meal had the highest fiber effective degradability (25.2%). Sunflower meal presented better values of ruminal parameters of dry matter, crude protein and neutral detergent fiber in relation to the other byproducts.