In situ ruminal degradability of dry matter, organic matter and crude protein of some concentrated supplements used in the feeding of bovines / Degradabilidade ruminal in situ da matéria seca, matéria orgânica e proteína bruta de alguns suplementos concentrados usados na alimentação de bovinos

ABSTRACT

Holstein steers, with permanent ruminal cannula, 650 kg of liveweight, maintained on pasture, and receiving mineral mixture ad libtum were used. The present study had the objective of evaluating the in situ ruminal degradation of the dry matter (DM), crude protein (CP) and organic matter (OM) of 12 concentrated feed whole sunflower seed (WSF), partially degreased sunflower (DSF), sunflower meal (SFM), sunflower pie pressed one time (T 1x), sunflower pie pressed two time (T 2x), for extracting of the oil, whole soybean seed (WS), partially degreased soybean (DS), soybean meal (SM), whole cottonseed (WC), cottonseed meal (CM), degreased corn germ (CG) and a commercial concentrate with 36% of CP (CC). The feed were grounded in a mill equipped with a screen with sieves of 2 mm of diameter. Samples 5 g of DM from each one of the mentioned feed were incubated in nylon bags with pores of 50 micras of diameter, measuring 14 x 7 cm, for the times of 12; 20; and 33 h of ruminal fermentation. The effective degradability (ED) of CP, for a passage rate of 5%/h varied from 62.08 to 95.93% for commercial concentrate and sunflower pie pressed two time for OM varied from 48.17 to 85.28% for soybean meal and whole cottonseed. The CC and CG presented the smallest ED of CP, however only the CC have larger protein escapes to be digested in the intestines, because CG presents little PB in its c

RESUMO

Foram utilizados quatro bovinos da raça holandesa, machos castrados, fistulados no rúmen, pesando em média 650kg, mantidos em pastejo e recebendo mistura mineral ad libtum. O presente trabalho teve como objetivo avaliar a degradação ruminal in situ da matéria seca (MS), proteína bruta (PB) e matéria orgânica (MO) de 12 alimentos concentrados grão de girassol integral (GI), grão de girassol parcialmente desengordurado (GD), farelo de girassol (FG), torta de girassol com uma passagem pela prensa (T 1x), torta de girassol com duas passagens pela prensa (T 2x), para retirada do óleo, grão de soja comercial (SI), grão de soja comercial parcialmente desengordurado (SD), farelo de soja (FS), caroço de algodão (CA), farelo de algodão (FA), gérmen de milho desengordurado (GM) e um concentrado comercial com 36% de PB (CC). Os alimentos foram moídos em moinhos dotados com peneira com crivos de 2 mm de diâmetro. Foram incubados 5 g de MS de cada um dos alimentos citados em sacos de náilon com poros de diâmetro de 50 micras, medindo 14 x 7 cm, para os tempos de 12; 20; e 33 h de fermentação ruminal. As degradabilidades efetivas (DE) da PB a uma taxa de passagem de 5%/h variaram de 62,08 a 95,93% para CC e TG2, e a MO de 85,28 a 48,17% para FS e CA. O CC e o GM apresentaram as menores DE da PB, porém somente o CC teria maiores escapes de proteína para ser digerida nos intestinos, pois o