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| Author(s): |
Filipe Zanferari
Total Authors: 1
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| Document type: | Doctoral Thesis |
| Press: | Pirassununga. |
| Institution: | Universidade de São Paulo (USP). Faculdade de Medicina Veterinária e Zootecnia (FMVZ/SBD) |
| Defense date: | 2017-03-31 |
| Examining board members: |
Francisco Palma Rennó;
Ives Cláudio da Silva Bueno;
Gilberto Vilmar Kozloski;
Arlindo Saran Netto;
Izabelle Auxiliadora Molina de Almeida Teixeira
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| Advisor: | Francisco Palma Rennó; Gilberto Vilmar Kozloski |
| Abstract | |
The present thesis was elaborated in three chapters, corresponding to sections 2, 3 and 4. In the first one, the aim was to evaluate the association of chitosan (C) and whole raw soybean (WRS) in diets, evaluating the intake, ruminal fermentation, digestibility and nutrient metabolism and its effects on milk production, milk fatty acids profile and the productive efficiency of lactating cows. Twenty four multiparous Holstein cows, eight of them fitted with ruminal cannula, were distributed in a replicated 4 × 4 Latin squares. The treatments were a combination of C and WRS diets arranged in a 2 × 2 factorial design. This association increased the efficiency of ruminal fermentation, reducing the bacterial population responsible for the biohydrogenation and increased the unsaturated fatty acids in milk. The C and WRS diets caused a significant reduction in DMI and nutrient digestibility, in microbial protein synthesis and milk yield. However, the addition of C in diets without a lipid supplementation may be a good nutritional strategy to increase the N retention and increase the food efficiency of lactating cows, and, indeed, to increase the unsaturated fatty acids content, mainly cis-9, trans-11 CLA. In the second chapter, the objective was to evaluate the external indicators Cr2O3 and TiO2 and the indigestible internal DM, NDF and ADF that were determined in in situ different incubation bags from the accuracy, precision and robustness of the fecal excretion estimates in a digestion assay with different dairy cow diets. Eight cows fitted with ruminal cannula were used to perform total fecal collection over 24, 48 and 72 hours. The Cr2O3 generated accurate estimates, however, the fecal recovery and robustness were affected by the ether extract intake. The TiO2 indicator showed incomplete fecal recovery, low accuracy, precision and robustness. Among the combinations for the internal indicators, the iNDF in polyester bags had a complete recovery and generated the most accurate and robust estimates. The lack of accuracy and precision of the indicators have a big impact on the digestibility estimates. In the third chapter, the aim was to evaluate the use of creatinine as an indicator of urinary volume. It would be possible to estimate the total excretion of purine derivatives to evaluate the ruminal microbial protein synthesis in different cow diets. Also, eight multiparous cows fitted with ruminal cannula were used to make total urine collection over 24, 48 and 72 hours. The creatinine was affected by the study experimental conditions, including dietary effect and variations according to period and animals. The relationship between observed and estimated excretion of purine derivatives should be viewed with caution, because the urinary volume was underestimated and the estimates did not identify the correct differences between diets, that could compromise the evaluations of ruminal microbial production. (AU) | |
| FAPESP's process: | 14/15302-5 - Chitosan associated with whole raw soybeans in the diet of lactating dairy cows: I. productive performance, digestion and metabolism. II. evaluation of techniques for estimating the apparent total tract digestibility and microbial protein synthesis |
| Grantee: | Filipe Zanferari |
| Support Opportunities: | Scholarships in Brazil - Doctorate (Direct) |