| Texto completo | |
| Autor(es): |
Silva, T. H.
;
Takiya, C. S.
;
Vendramini, T. H. A.
;
Ferreira de Jesus, E.
;
Zanferari, F.
;
Renno, F. P.
Número total de Autores: 6
|
| Tipo de documento: | Artigo Científico |
| Fonte: | ANIMAL FEED SCIENCE AND TECHNOLOGY; v. 221, p. 9-pg., 2016-11-01. |
| Resumo | |
Exogenous fibrolytic enzymes (EFE) can increase ruminal digestion of neutral detergent fiber (NDF) and improve its fermentation for cattle. Twenty-four multiparous Holstein cows (33.72 +/- 7.63 kg milk/d and 176 +/- 82.27 days in milk - DIM, at the start of the experiment) were used in a replicated 4 x 4 Latin square experimental design. Increasing doses of a commercial product was used to evaluate the effect of xylanase activity (100 units per gram of product) on intake and total-tract digestion of nutrients, sorting index, chewing time, milk yield and composition, N use, and ruminal fermentation. Treatments consisted of 0, 8, 16 or 24 g/d per cow of EFE product mixed into the concentrate. Corn silage was used as forage source. The basal diet had a forage-to-concentrate ratio of 50:50 (dry matter basis). Even though EFE supplementation had a positive linear effect on dry matter and NDF intake, it had no impact on total-tract digestion of nutrients. Moreover, this enzyme promoted a linear increase of the intake of feed with larger particle size (>19 mm) and quadratically affected rumination and chewing activity (hours), reaching the highest values at intermediate doses (8 g/d and 16 g/d). Treatments had no effect on milk yield and composition; however, the N use efficiency was linearly decreased by EFE, reducing thus the ability to synthesize milk and quadratically decreasing N retention. No treatment effect was found on ruminal pH, whereas a negative quadratic effect on ruminal NH3-N concentration was significant. Regarding ruminal parameters, this enzyme supplementation provided linear increased in acetate, propionate, butyrate, and total short-chain fatty acids synthesis. As result, EFE supplementation improved DM and NDF intake, increasing the time spent chewing and ruminating, leading to a greater total short-chain fatty acids production in rumen. Nonetheless, EFE did not improve milk yield and composition of mid-lactating dairy cows. (C) 2016 Elsevier B.V. All rights reserved. (AU) | |
| Processo FAPESP: | 14/13202-3 - Enzimas Fibrolíticas na Alimentação de Vacas Leiteiras |
| Beneficiário: | Thiago Henrique da Silva |
| Modalidade de apoio: | Bolsas no Brasil - Mestrado |