Effects of supplemental degradable intake protein on utilization of medium- to low-quality forages.

Abstract

Three independent experiments were conducted each using 16 ruminally fistulated beef steers fed bermudagrass (8.2% CP, 71% NDF; Exp. 1), bromegrass (5.9% CP, 65% NDF; Exp. 2), or forage sorghum (4.3% CP, 60% NDF; Exp. 3) hays to evaluate the effects of increasing level of supplemental degradable intake protein (DIP) on forage utilization. In each experiment, steers were blocked by weight and assigned to one of four treatments, and hay was offered to each steer at 130% of average voluntary intake for the preceding 5-d period. Supplemental DIP (sodium caseinate) was placed in the rumen at 0700, immediately before feeding forage. Levels of DIP supplementation were .041, .082, and .124% BW; the control received no supplemental DIP. Following a 10-d adaptation, intake and total fecal output were measured for 7 d. In Exp. 1, neither forage OM intake (FOMI) nor fiber (NDF) digestion were influenced (P > or = .20) by increasing level of DIP supplementation. The DIP supplied by the bermudagrass hay was estimated to be 8.2% of the total digestible OM intake (TDOMI) for control steers. In Exp. 2, increasing level of supplemental DIP did not affect (P > or = .26) FOMI but tended to increase total OM intake linearly (TOMI; P = .10). The tendency for a rise in TOMI coupled with a slight numeric increase in digestion resulted in an increase (linear; P = .06) in TDOMI. In the treatment group in which the maximum TDOMI was observed (supplemental DIP treatment of .082% BW), total DIP intake constituted approximately 9.8% of the TDOMI. In Exp. 3, FOMI, TOMI, organic matter digestion (OMD), and TDOMI were improved (P < .01) by increasing amounts of supplemental DIP. Although there was some evidence of a tendency for a decrease in the magnitude of change in TDOMI in response to increasing DIP supplementation, a clear plateau was not achieved with the levels of supplement provided. When the highest level of supplemental DIP was fed, DIP constituted approximately 12.8% of the TDOMI. In conclusion, significant variation was observed among forage in the amount of DIP needed to maximize intake and digestion when expressed in relationship to the digestible OM.

Intake and digestibility in cattle fed low-quality tropical forage and supplemented with nitrogenous compounds

“…Increases in voluntary intake as a function of supplementation with nitrogenous compounds were also observed by Hannah et al (1991), Mathis et al (2001), Köster et al (2002), and Ortiz-Rubio et al (2007) in cattle fed low-quality forage.…”

Consumo e digestibilidade de feno de baixa qualidade suplementado com nitrogênio não protéico em bovinos

“…Fórmula dos suplementos (base úmida) utilizados nos tratamentos (T1 a T5) e composição bromatológica mé-dia, em porcentagem, de proteína bruta (PB), equivalente protéico em nitrogênio não protéico (EPNNP) e uréia, e nível de suplementação em porcentagem do peso vivo (Oferta). Mathis et al (2000), que ao suplementar com teores crescentes de proteína degradável no rúmen (0, 0,041, 0,082 e 0,124% PV) e utilizar feno de sorgo de baixa qualidade (4,3% PB e 59,5% FDN), obtiveram respostas lineares para a digestibilidade da FDN (DFDN), assim como para a digestibilidade da matéria orgânica (DMO). Koster et al (1997) obtiveram resposta quadrática para a DMO e tendência à resposta quadrática para a DFDN (p = 0,06), na substituição gradativa do nitrogênio suplementar, proveniente de uma fonte de proteí-na verdadeira, por uréia.…”

“…Provavelmente, as limitações provêm de características da forragem consumida (fermentabilidade inerente e disponibilidade da proteína) e da necessidade de proteína pelo animal (Koster et al, 1997;Mathis et al, 2000).…”

“…A otimização dessa relação permite aumentar o consumo e a digestibilidade, em decorrência de alterações do ambiente ruminal, que resultam em melhor desempenho produtivo e reprodutivo dos animais (Mathis et al, 2000).…”

Effects of protein and energy supplementation on growth, forage intake, forage digestion and nitrogen balance in meat goat kids

“…Protein supplements increase intake and utilization of low-quality forages in cattle (Kö ster et al, 1996), as do high-protein concentrates (Negesse et al, 2001) and leguminous forage (Osuji and Odenyo, 1997) supplementation to goats. However, it has been shown that protein supplements have little effect on feed intake of cattle consuming forages with CP concentrations above approximately 6% (Mathis et al, 2000). This number may be greater in growing goats whose minimum DM dietary protein concentration for maintenance is estimated at 6.0% to 8.5% depending on age (National Academies Press, 2007).…”