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| Author(s): |
Thiago Henrique da Silva
Total Authors: 1
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| Document type: | Master's Dissertation |
| Press: | Pirassununga. |
| Institution: | Universidade de São Paulo (USP). Faculdade de Medicina Veterinária e Zootecnia (FMVZ/SBD) |
| Defense date: | 2016-02-11 |
| Examining board members: |
Francisco Palma Rennó;
Marcos Veiga dos Santos;
Arlindo Saran Netto
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| Advisor: | Francisco Palma Rennó |
| Abstract | |
The aim of this study was to evaluate the use of exogenous fibrolytic enzyme in lactating cows diets and their effect on intake and total-tract apparent digestibility of dry matter and nutrients, fermentation and synthesis of ruminal microbial protein, milk yield and composition, metabolic profile and energy and nitrogen balance. Twenty-four multiparous Holstein cows were used in 4x4 Latin Square design, with 646.75 ± 77.54 kg of body weight, 3.02 ± 0.56 of body condition score, 176 ± 82.27 days in milk and 33.72 ± 7.63 kg/day of milk yield at the start of the study. Animals were randomized to receive the following treatments: 1) Control (0), comprises basal diet without the addition of fibrolytic enzyme; 2) with addition of 8 g/cow/day of fibrolytic enzyme; 3) with the inclusion of 16 g/cow/day of fibrolytic enzyme; 4) with inclusion of 24 g/cow/day of fibrolytic enzyme (Fibrozyme® - Alltech Inc., Nicholasville, KY). Exogenous fibrolytic enzymes in feed resulted in increased of dry matter, organic matter and neutral detergent fiber intake. Long particles intake increased linearly with fibrolytic enzyme inclusion in the diet. Cows supplemented with fibrolytic enzyme showed quadratic effect on the rumination and chewing activities. The increase in dry matter intake reflected in the linear increase in net energy intake and net energy balance. There was quadratic effect on the concentration of ruminal NH3-N and a linear increase in the amount of acetic, propionic and butyric acids in the rumen. There was quadratic effect in the ruminal microbial synthesis. There were no differences in milk yield and components production. There was a linear increase in the body weight gain with use of fibrolytic enzyme. There was quadratic effect in nitrogen urine excretion with quadratic effect on the nitrogen balance. Thus, exogenous fibrolytic enzyme is effective in increasing dry matter and NDF intake and improve the fermentation efficiency of dairy cows increase energy balance, but was not effective in increase the milk yield of Holstein cows in the third of lactation (AU) | |
| FAPESP's process: | 14/13202-3 - Fibrolytics Enzymes in dairy cows diets. |
| Grantee: | Thiago Henrique da Silva |
| Support Opportunities: | Scholarships in Brazil - Master |