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| Author(s): |
Joao Ricardo Alves Pereira
Total Authors: 1
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| Document type: | Master's Dissertation |
| Press: | Piracicaba. |
| Institution: | Universidade de São Paulo (USP). Escola Superior de Agricultura Luiz de Queiroz (ESALA/BC) |
| Defense date: | 1995-02-16 |
| Advisor: | Max Lazaro Vieira Bose |
| Abstract | |
To verify the use the "Cornell Net Carbohydrate and Protein System" (CNCPS) under Brazilian conditions the bromatological composition, potential and effective degradation, and degradation rates of dry matter (DM), crude protein (CP), neutral detergent insoluble nitrogen (NDIN), neutral detergent fiber (NDF) and starch (ST) were determined for corn silage, cotton seed meal and corn in diets with roughage:concentrate ratios of 80:20 (D1) and 60:40 (D2). Four nelore, castrated males, with an average weight of 520 kg were used. The higher concentrate level resulted in a reduction (P < 0,05) in the potentially degradable DM for corn silage and cotton seed meal, and in an increase for corn. For corn silage, the increase in concentrate from 20 to 40% resulted in reductions of potentially digestible NDF and degradation rates of DM, NDF and NDIN. Also, an increase in the degradation rates of CP and ST (P > 0,05) was observed. For cotton seed meal, the increase in concentrate resulted in reductions of potentially degradable NDF, and degradation rates of DM, CP, NDF. Also, an increase in the degradation rate of CP was found, although it was not significant (P > 0,05). For corn, the increase in concentrate resulted in an increase in potentially degradable CP and ST and degradation rates of DM, CP, and ST (not significant P > 0,05). The animal effect was higly significant (P < 0,01) for the effective degradation of all fractions evaluated. This suggest that not only uniformity of the animals should be considered, but also other factors involved, such as ruminal pH and diet passage rate, should be taken into account. The diets and use of lag time in the calculation had no significant effect (P > 0,05) upon potential degradation of the feedstuffs fractions studied. The use of lag time significantly increased effective degradation of DM (EDDM) for corn silage for the two diets (P < 0,05). The effect of lag time and diet upon effective degradation of CP, NIDN, NDF and ST resulted in variations of up to 22% (not significant P > 0,05). Even though the diets had no effect (P > 0,05), the use of lag time significantly increased (P < 0,05) cotton seed meal EDDM by 14% for D1 and 15% for D2. The diets and the use of lag time had no effect (P > 0,05) in the degradation of CP, NDIN and NDF. There was a diet effect (P < 0,05) on corn EDDM when lag time was not considered. This resulted in an 10% increase for diet D2. Furthermore, the use of lag time significantly increased (P < 0,05) EDDM in D1 by 22,6% and 18% in D2. The degradation of the CP and ST fractions were not significantly altered (P < 0,05) by the use of lag time. The degradation of silage ST was superior to that of corn ST. It is important to note that this difference is not evident when the estimations are made by CNCPS. This suggest that more studies should be conducted in this area. The degradation of CP and NIDN fractions were relatively high when compared to literature and CNCPS. It is important of mention that the animals utilized in this study were zebu. On the other hand, the diets could be associated with this finding, which also suggest a need to conduct studies that compare different species. (AU) | |