Comparative evaluation of fiber effectiveness of forage and byproducts. / Análise comparativa da efetividade da fibra de volumosos e subprodutos.

AUTOR(ES)
DATA DE PUBLICAÇÃO

2003

RESUMO

Two experiments were conducted to evaluate fiber effectiveness of forages and byproducts. In experiment I, five ruminally cannulated Holstein cows were used in a 5 x 5 Latin square design to evaluate fiber effectiveness of sugarcane (SC) and sodium hydroxide treated sugarcane (SHSC). Low and high forage diets (14 and 22% of dietary DM from corn silage NDF, respectively) were compared with diets formulated to contain 14% of DM from corn silage NDF plus 8% of DM from SC NDF or SHSC NDF or alfalfa hay NDF (AF). Dry matter intake, milk yield and composition did not differ across diets. Ruminal pH, VFA and acetate:propionate were affected by level and source of NDF. Chewing time (min./d and min./kg of DMI) was lower for low forage diet but, did not differ between high forage, SC, SHSC and AF diets. The results suggest that SC, SHSC and AF were as effective as corn silage for maintaining milk fat test and stimulating chewing. In experiment II, six ruminally cannulated Holstein cows were used in a 6 x 6 Latin square design to evaluate the role of specific fractions of whole cottonseeds in sustaining rumen function as mesuared by mat consistency, particulate passage rate, and chewing response. Whole cottonseeds (WCS), starch-coated WCS (EAS), mechanically delinted cottonseed (DEL) and pelleted WCS (PEL) were used and the six dietary treatments were: low forage diet (LFD) – 16% of DM from forage NDF (FNDF); high forage diet (HFD) – 21% of DM from FNDF; WCS – 16% FNDF plus 5% of DM from WCS NDF; EAS - 16% FNDF plus 5% of DM from EAS cottonseed; DEL - 16% FNDF plus 5% of DM from DEL cottonseed, and PEL - 16% FNDF plus 5% of DM from DEL cottonseed, and PEL - 16% FDNF plus 5% of DM from pelleted WCS. Dry matter intake did not differ across cottonseed treatments but it was higher than HFD treatment. Milk yield was higher for LFD but, milk fat percentage was not affected treatments. Ruminating and chewing activity were lower for cottonseed diets than HFD. Fiber effectiveness was lower for cottonseed and it was not possible to isolate the role of linter or particle size in sustaining rumen.

ASSUNTO(S)

alimentos volumosos fibras vegetais subprodutos para animais roughage feeds lactação animal animal forage feedstuffs lactating animal by-products feedstuffs animal diet alimentos vegetais para animais fiber dieta animal

ACESSO AO ARTIGO

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