Influence of mass and volume of ruminal contents on voluntary intake and digesta passage of a forage diet in steers.

Abstract

To assess the influence of volume and mass of ruminal contents on voluntary intake and related variables, five ruminally cannulated steers (550 kg) were fed a low-quality forage diet (43.1% ADF, 8.1% CP) in a 5 x 5 Latin square experiment. Mass and volume of ruminal contents were altered by adding varying numbers and weights of filled tennis balls (6.7-cm diameter) to the rumen immediately before the initiation of each experimental period. Treatments consisted of 0 balls (control), 50 balls with a 1.1 specific gravity (SG), 100 balls with a 1.1 SG, 50 balls with a 1.3 SG, and 100 balls with a SG of 1.3. The total volume of balls was 7.25 and 14.5 L for 50 and 100 balls, respectively. The total weight of balls was 8.5 and 17 kg for 50 and 100 balls with a 1.1 SG and 10.75 and 21.5 kg for 50 and 100 balls with a 1.3 SG, respectively. Daily DMI was 8.3, 7.3, 7.0, 6.5, and 6.0 kg for control; 50, 1.1 SG; 50, 1.3 SG; 100, 1.1 SG; and 100, 1.3 SG, respectively. Addition of balls to the rumen reduced (P < .01) DMI. Increasing the number (P < .01) and SG (P <. 01) of the balls decreased DMI further. However, digestibilities of DM, NDF, ADF, and CP were not influenced by treatment. Increasing the number of balls in the rumen increased (P < .05) rate of passage of digesta from the rumen, but increasing SG of the balls did not alter rate of passage. There was a treatment x hour interaction (P < .05) in the proportion of ruminal digesta with a functional specific gravity (FSG) less than 1.1, which decreased with time after feeding for the control but increased with time after feeding for other treatments. Ruminal passage rate of inert particles added in the rumen of different SG (1.1 and 1.3) and length (1 and 3 mm) decreased (P < .05) as SG of the balls increased. Mean fecal particle size was greater for those treatments with the heavier balls. Both the number and SG of balls (P < .10) influenced total VFA, and total concentrations were greater for the control and for the 1.1 SG than for the 1.3 SG treatments.

Controlled feeding trials with ungulates: a new application of in vivo dental molding to assess the abrasive factors of microwear

“…The latter is important as hay-fed sheep have been observed spending an average of 8.3 h day −1 ruminating (Domingue et al, 1991) and the mineral composition of cattle boluses is similar to diet with ∼88% of dietary silica returning to the mouth during rumination (Little, 1975;Mayland and Lesperance, 1977). Furthermore, specific gravity of particles is inversely correlated to the particles' retention time in the ruminant digestive system (Poncet, 1991;Schettini et al, 1999). As particles with a specific gravity of less than 1.04 pass through cow digestive tracts within 72 h (Hristov et al, 2003), 5 days was sufficient for quartz grains (specific gravity=2.65) to pass through the sheep reticulo-rumen and avoid treatment overlap.…”

Influence of mass of ruminal contents on voluntary intake and digesta passage in steers fed a forage and a concentrate diet1

“…It was our hypothesis that as the weight of inert bulk added in the rumen increases, DMI will decrease, but to different degrees depending on whether it is a forage-or a concentrate-based diet. The objective of this study was to ascertain whether ruminal location of the added inert bulk influenced the results previously reported (Schettini et al, 1999). In addition, the effect of density of ruminal contents on DMI and other ruminal variables was examined in steers fed a high-concentrate diet.…”

“…A decrease in DMI of ruminants has been reported by adding or by displacing ruminal space of animals fed forage diets with inert bulk (Anil et al 1993;Dado and Allen, 1995;Schettini et al, 1999). These results led to the conclusion that gastrointestinal fill is an important consideration in the voluntary intake of ruminants fed a forage diet.…”

“…The influence of ruminal fill on voluntary intake of ruminants has been fairly well documented; however, the influence of mass of ruminal contents on voluntary intake has not been studied extensively. Schettini et al (1999) demonstrated that mass, in addition to the volume of the inert bulk added to the rumen, had significant effects on DMI of steers fed a forage diet. They reported that for each kilogram of weight added to the rumen of the steers, a depression of 112 g in DMI was observed.…”

Suplementação de Novilhos Mestiços em Pastejo na Época de Transição Água-Seca: Desempenho Produtivo, Características Físicas de Carcaça, Consumo e Parâmetros Ruminais

“…), observaram elevação de 19,5 para 43,2 horas para idades de corte de 61 e 124 dias, destacando que a porção Tabela 7 -Médias e coeficientes de variação para as porcentagens e quantidades de músculo (MUS), gordura (GOR) e ossos (OSS), o comprimento de carcaça (CCAR), a gordura subcutânea (GOSUB), o rendimento de carcaça (RCPV), a área de olho de lombo (AOL), a relação músculo:osso (RELMO) e a relação gordura:músculo (RELGM), em função dos tratamentos indigestível da fibra respondera por 32 e 77% do efeito total, respectivamente. Embora existam evidências de adaptação do animal ao aumento no conteúdo de componentes indigestíveis na dieta por intermédio da ampliação do volume e pool de digesta residente no rúmen (Schettini et al, 1999), limites são definidos, além dos quais o consumo é reduzido permanentemente (Van Soest, 1994). Dessa forma, a maior concentração de FDNi observada durante o mês de maio (Tabela 4) pode ter efetivamente colaborado para o menor consumo de MS observado sobre os suplementos MDPS e FTRIGO, por ocasionar maior efeito de repleção ruminal.…”