The present study was conducted to evaluate the nutritional value and in situ degradation kinetics of eight high protein forage crops: alfalfa (Medicago sativa L.), forage oat (Avena sativa L.), ...mixed pasture, and ryegrass (Lolium multiflorum Lam.) pasture in early vegetative stages, two forage lupins (Lupinus albus L.) in early bloom stages, sugar beet (Beta vulgaris L.) and kale (Brassica napus var. pabularia (DC.) Rchb.) leaves at root maturity. Dry matter (DM) and crude protein (CP) degradation kinetics were evaluated by the nylon bag technique through the in situ procedure described by Ørskov and MacDonald (1979) using three ruminally cannulated sheep. Chemical composition of the forage crops showed on average 13.7% DM; 21.4% CP; 31.5% neutral detergent fiber (NDF); 17.7% crude fiber (CF), 80.6% digestibility of organic matter (DOMD) and 12.13 MJ kg^sup -1^ metabolizable energy (ME). The high total degradability of forage crops reported here (> 87% DM; > 93% CP) can be associated with the presence of large quantities of fraction a (> 34% DMa; > 29% CPa) and high degradability of fraction b, resulting in low amounts of undegradable fraction (U) (7.02% DM and 3.55% CP). Correlations between CPb and DMb degradability (r = 0.79) and CPc and DMc degradation rates (r = 0.78) were high, however differences in c were not explained by differences in CP or NDF contents, nor by the amounts of a or b fractions. Degradation for DM and CP during the first 6 h of incubation was strongly and inversely correlated to b (36 h) (r = 0.93) (P < 0.0001) regardless of forage type. The amounts of CPa and CPb influenced effective degradability of CP (r = 0.79; P < 0.02), EDp increased with increased CPa and decreased with increased CPb (r = 0.76; P < 0.02). Therefore, more than 75% of the forage crops degraded within the first 6 h of incubation, which was associated with the DM content and amount of the slowly degradable fraction present. Degraded proportions of fraction b among forage crops, along with incubation periods, were variable (Figure 2A and 2B). Most part of fraction b disappeared within the first 6 h of incubation (CPb: 57.7-84.8% and DMb: 52.3-75.2%) regardless of fraction size. After 6 h of incubation, more than 80% of CPb was degraded in mixed pasture and oat forage, which presented the highest degradation rates (0.314% h-1 and 0.294% h-1). As well, the proportion degraded during this period correlated strongly and inversely (P < 0.0001) with the total amount of b (r = 0.93) for DM and CP, regardless of forage type. On average, 68% of CPb (Figure 2A) and 61% of DMb (Figure 2B) was degraded at 6 h of incubation. Correlations of CPc with CP, fraction a and b were low. Therefore, there might be other factors affecting early degradability of CP. Although forage crops responded differently in terms of CP compared to DM degradability of fraction b, the DMb degradability fraction is explained mainly by CPb degradability (r = 0.79) and the rate of degradation (r = 0.79) was positive and significant (P < 0.02). Differences in degradation rates could be due to amounts of intracellular components and digestibility, while N availability is due to its distribution among cell structures. In fact, it has been reported that neutral detergent insoluble N (NDIN) requires a greater lag time for degradation than the N pool, regardless of forage type and maturity (Coblentz et al., 1999). On the other hand, intracellular N is quickly available (1-2 h) and diminishes rapidly with time (Aufrère et al., 2000). Under these conditions, the high degree degradability observed during the first 6 h of fermentation could be associated with low NDIN in mixed pasture and oat forage, and therefore the higher content of NDF was not a limiting factor for degradation (Table 1). The slower rates of degradation found in lupin in early bloom and kale leaf could be influenced by a higher proportion of ADIN, despite its low NDF and higher b fraction. In general, the results indicate that as incubation time increased, differences in degradability among forage crops decreased, reaching nearly 90% of the degradable CPb and 85% of DMb fractions in just 12 h. Cinética de degradación ruminal in situ en forrajes de alto contenido proteico en clima templado. El presente estudio se desarrolló con el objetivo de evaluar el valor nutricional y la cinética de degradación in situ de ocho forrajes de alto valor proteico: alfalfa (Medicago sativa L.), avena (Avena sativa L.), pastos mixtos y pastos de ballica (Lolium multiflorum Lam.), en las primeras etapas vegetativas, dos lupinos forrajeros (Lupinus albus L.) en etapas inicio de la floración, hojas de remolacha azucarera (Beta vulgaris L.) y de col (Brassica napus var. pabularia (DC.) Rchb.) La cinética de degradación ruminal de la materia seca (DM) y proteína cruda (CP) se evaluaron mediante la técnica in situ de la bolsa de nylon descrita por Ørskov MacDonald (1979), con tres ovejas-fistuladas, en cinco tiempos de incubación. La composición química de los forrajes fue en promedio 13,7% DM, CP 21,4%; 31,5% de fibra detergente neutro (NDF), 17,7% fibra cruda (CF); digestibilidad de la materia orgánica (DOMD) 80,6% y 12,13 MJ kg-1 energía metabolizable (ME). La degradabilidad total de los forrajes fue alta (> 87% DM; > 93% CP) asociada a la presencia de grandes cantidades de la fracción a (> 34% DMa; > 29% CPa) y a la alta degradabilidad de la fracción b, determinando cantidades bajas de la fracción no degradable (U) (7,02% DM y 3,55% CP). Las correlaciones entre la degradabilidad CPb y DMb (r = 0,79) y entre CPc y DMc (r = 0,78) fueron altas; sin embargo, las diferencias en c no se explican por las diferencias en CP o contenido de NDF, ni por la cantidad de fracciones de a o b. La degradación de DM y CP durante las primeras 6 h de incubación se correlacionó inversamente con b (36 h) (r = 0,93; P < 0,0001), independiente del tipo de forraje. La cantidad de CPa y CPb influenció la degradabilidad efectiva de CP (r = 0,79; P < 0,02), al aumentar CPa también lo hizo DEp y, disminuyó al aumentar la CPb (r = 0,76; P < 0,02). Por lo tanto, la PC y MS de estos forrajes se degradó en más del 75% en las primeras 6 h de incubación y esto puede asociarse con el contenido de DM y la cantidad de fracción lentamente degradable presente.
Effect of Including Extruded, Rolled or Ground Corn in Dairy Cow Diets Based on Direct Cut Grass Silage Alvarado G, Christian(Instituto de Investigaciones Agropecuarias INIA Centro Regional de Investigación Carillanca); Anrique G, René(Universidad Austral de Chile Facultad de Ciencias Agrarias); Navarrete Q, Soledad(Universidad Austral de Chile Facultad de Ciencias Agrarias)
Chilean journal of agricultural research,
09/2009, Volume:
69, Issue:
3
Journal Article
Open access
A study was conducted to determine the effect of corn (Zea mays L.) grain processing on intake, digestibility of nutrients and milk production and composition. The effect of extrusion on nutrient ...digestibility was evaluated in trial 1, using ground corn as a control. In trial 2, the effect of extrusion on intake was evaluated, comparing extruded corn of two densities (357 and 308 g L-1) with rolled corn (507 g L-1) as a control. In trial 3, the effects of extrusion on milk production, digestibility and intake were evaluated; using steam rolled corn and ground corn as controls. No effects on dry matter and metabolizable energy intakes due to differences in the extruded corn grains were observed. Digestibility of dry matter, organic matter, crude protein, gross energy and neutral detergent fiber did not differ among treatments, although a greater digestibility of non-fibrous carbohydrates was observed. Higher milk production was obtained in treatments including extruded and steam rolled corn (21.4 and 21.6 L d-1), compared to ground corn (20.5 L d-1) but differences disappeared when standardizing for fat content. Milk composition was not affected by treatments. Daily protein production was greater (P < 0.01) in treatments including extruded and rolled corn. Blood parameters (ß-hydroxybutyrate, urea) and milk urea remained within normal reference values. It was concluded that using extruded corn had no adverse effects on digestibility or forage and total intake with a small advantage in milk protein yield comparing with ground corn, but without clear differences compared to steam rolled corn.
Se estudiaron los efectos del procesamiento del grano de maíz (Zea mays L.) en el consumo y digestibilidad de la dieta, y en la composición y producción láctea. En el ensayo 1, se evaluó el efecto de la extrusión en la digestibilidad de la dieta utilizando maíz molido como control. En el ensayo 2, se evaluó el efecto de la extrusión en el consumo comparando maíz extruido de dos densidades (357 y 308 g L-1) usando maíz rolado (507 gL-1) como control. En el ensayo 3, se evaluó el efecto de la extrusión sobre la producción de leche, digestibilidad y consumo, empleando maíz rolado y maíz molido como controles. No se observaron diferencias en consumo de materia seca (MS) ni de energía metabolizable atribuibles a diferencias de densidad del maíz extruido. La digestibilidad de la MS, materia orgánica, proteína bruta, energía bruta y fibra detergente neutro no difirió entre tratamientos, aunque se observó una mayor digestibilidad de los carbohidratos no fibrosos. Hubo mayor producción de leche en tratamientos donde se incluyó maíz extruido y maíz rolado (21,4 y 21,6 Ld-1), respecto del maíz molido (20,5 L d-1), pero esta diferencia no se mantuvo al corregir por contenido graso. Los tratamientos no afectaron la composición láctea. La producción diaria de proteína fue mayor (P < 0,01) en los tratamientos con maíz extruido y rolado y no hubo diferencias en la producción diaria de grasa. La urea y ß-hidroxibutirato sanguíneos y urea en leche se mantuvieron dentro de los valores de referencia. Se concluyó que el maíz extruido no tuvo efectos adversos sobre la digestibilidad, ni sobre el consumo de forraje y de alimento total, con una leve ventaja en la producción de proteína láctea al comparar con maíz molido, pero sin diferencias claras al comparar con maíz rolado al vapor.
The present study was conducted to evaluate the nutritional value and
in situ degradation kinetics of eight high protein forage crops:
alfalfa ( Medicago sativa L.), forage oat ( Avena sativa L.), ...mixed
pasture, and ryegrass ( Lolium multiflorum Lam.) pasture in early
vegetative stages, two forage lupins ( Lupinus albus L.) in early
bloom stages, sugar beet ( Beta vulgaris L.) and kale ( Brassica
napus var. pabularia (DC.) Rchb.) leaves at root maturity. Dry matter
(DM) and crude protein (CP) degradation kinetics were evaluated by the
nylon bag technique through the in situ procedure described by
Ørskov and MacDonald (1979) using three ruminally cannulated
sheep. Chemical composition of the forage crops showed on average 13.7%
DM; 21.4% CP; 31.5% neutral detergent fiber (NDF); 17.7% crude fiber
(CF), 80.6% digestibility of organic matter (DOMD) and 12.13 MJ kg-1
metabolizable energy (ME). The high total degradability of forage crops
reported here (> 87% DM; > 93% CP) can be associated with the
presence of large quantities of fraction a (> 34% DMa; > 29% CPa)
and high degradability of fraction b, resulting in low amounts of
undegradable fraction (U) (7.02% DM and 3.55% CP). Correlations between
CPb and DMb degradability (r = 0.79) and CPc and DMc degradation rates
(r = 0.78) were high, however differences in c were not explained by
differences in CP or NDF contents, nor by the amounts of a or b
fractions. Degradation for DM and CP during the first 6 h of incubation
was strongly and inversely correlated to b (36 h) (r = 0.93) (P <
0.0001) regardless of forage type. The amounts of CPa and CPb
influenced effective degradability of CP (r = 0.79; P < 0.02), EDp
increased with increased CPa and decreased with increased CPb (r =
0.76; P < 0.02). Therefore, more than 75% of the forage crops
degraded within the first 6 h of incubation, which was associated with
the DM content and amount of the slowly degradable fraction present.
A study was conducted to determine the effect of corn ( Zea mays L.)
grain processing on intake, digestibility of nutrients and milk
production and composition. The effect of extrusion on nutrient
...digestibility was evaluated in trial 1, using ground corn as a control.
In trial 2, the effect of extrusion on intake was evaluated, comparing
extruded corn of two densities (357 and 308 g L-1) with rolled corn
(507 g L-1) as a control. In trial 3, the effects of extrusion on milk
production, digestibility and intake were evaluated; using steam rolled
corn and ground corn as controls. No effects on dry matter and
metabolizable energy intakes due to differences in the extruded corn
grains were observed. Digestibility of dry matter, organic matter,
crude protein, gross energy and neutral detergent fiber did not differ
among treatments, although a greater digestibility of non-fibrous
carbohydrates was observed. Higher milk production was obtained in
treatments including extruded and steam rolled corn (21.4 and 21.6 L
d-1), compared to ground corn (20.5 L d-1) but differences disappeared
when standardizing for fat content. Milk composition was not affected
by treatments. Daily protein production was greater (P < 0.01) in
treatments including extruded and rolled corn. Blood parameters
(ß-hydroxybutyrate, urea) and milk urea remained within normal
reference values. It was concluded that using extruded corn had no
adverse effects on digestibility or forage and total intake with a
small advantage in milk protein yield comparing with ground corn, but
without clear differences compared to steam rolled corn.
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