Ruminal degradation of switchgrass, big bluestem, and smooth bromegrass leaf proteins

Redfearn, Daren D.; Moser, Lowell E.; Waller, Steven S.; Klopfenstein, Terry J.

doi:10.2527/1995.732598x

Cited by 24 publications

(11 citation statements)

References 24 publications

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“…The hays used in this experiment were chosen because we expected differences in leaf to stein ratios (Cherney et al, 1990) and protein fractions (Sniffen et al, 1992) between these warm-and cool-season grasses. These compositional changes cause distinct rurninal disappearance rates, which in I iirii affect N metabolism (Redfearn et al, 1995). We expected the gamagrass to have a greater leaf to stein ratio and different leaf characteristics than orchardgrass.…”

Section: Expmentioning

confidence: 99%

Urea metabolism in beef steers fed tall fescue, orchardgrass, or gamagrass hays1,2

Huntington¹,

Magee²,

Matthews³

et al. 2009

Journal of Animal Science

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Two experiments were conducted to assess effects of endophyte treatments (Exp. 1), forage species (Exp. 2), and supplementation (Exp. 2) on urea production, excretion, and recycling in beef steers. Infusion of (15,15)N-urea and enrichment of urea in urine samples were used to calculate urea-N entry and recycling to the gut. Acceptably stable enrichment of (15)N-urea in urine was obtained after 50 h of intrajugular infusion of (15,15)N-urea, indicating that valid data on urea metabolism can be obtained from steers fed forages twice daily. After adjustment by covariance for differences in N intake among treatments in Exp. 1, steers fed endophyte-infected tall fescue had less (P<0.10) urea-N entry, recycling to the gut, and return of recycled urea-N to the ornithine cycle than those fed endophyte-free or novel endophyte-infected tall fescue. However, urea-N urinary excretion or return to the gut was similar among endophyte treatments when expressed as a proportion of urea-N entry. Urea-N entry and return to the gut in Exp. 2 was similar in steers fed gamagrass or orchardgrass hay after adjustment by covariance for differences in N intake. Less (P<0.01) urinary excretion, expressed as grams per day or as a proportion of urea-N entry, with gamagrass than with orchardgrass was associated with faster in vitro NDF-N digestion with gamagrass. Supplementation of gamagrass or orchardgrass with 1.76 kg/d of readily fermentable fiber and starch decreased urea entry (P<0.06) and urinary excretion of urea (P<0.01). Interactions between hay source and supplement reflected a greater response to supplementation for steers fed orchardgrass than for those fed gamagrass. After adjustment for differences among treatments in N supply, results of both experiments support the concept of improved N use in response to increased carbohydrate fermentability in the rumen, due either to inherent differences in forage fiber or to supplementation with readily fermentable carbohydrate (starch or fiber). Closer coordination of ruminal fermentation of carbohydrate and N sources provided greater and more efficient capture of dietary N as tissue protein in forage-fed steers.

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Section: Expmentioning

confidence: 99%

Urea metabolism in beef steers fed tall fescue, orchardgrass, or gamagrass hays1,2

Huntington¹,

Magee²,

Matthews³

et al. 2009

Journal of Animal Science

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“…More dietary AA reach the small intestine when protein is protected from ruminal degradation, potentially increasing animal performance ( 6 ) . Ruminal degradability of forage CP is highly variable among forage species (5,13,14) and is affected by stage of maturity (9,13). The RDP and RUP of forages may be deficient if they are harvested during certain stages of development.…”

Section: Introductionmentioning

confidence: 99%

Relationships Between In Situ Protein Degradability and Grass Developmental Morphology

Mitchell¹,

Redfearn²,

Moser³

et al. 1997

Journal of Dairy Science

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The objective of this research was to determine the relationships between the morphological development and in situ ruminally degradable protein (RDP), ruminally undegradable protein (RUP), and microbial protein of two cool season grasses (intermediate wheatgrass and smooth bromegrass) and two warm season grasses (switchgrass and big bluestem). The initial growth of grass tillers grown near Mead, Nebraska was clipped at ground level six times during the 1992 growing season and morphologically classified. Mean stage was calculated. Forage was ground to pass a 2-mm screen and was incubated in ruminally fistulated steers for 16 h. The RUP was adjusted for microbial protein and acid detergent insoluble N. The mean stage of cool season grasses was higher than that of warm season grasses throughout the growing season. The RDP decreased as plant maturity increased for all species. The RUP expressed as a percentage of crude protein for the cool season grasses was lower than that for warm season grasses. The RUP for intermediate wheatgrass, smooth bromegrass, and switchgrass remained constant across maturities, but RUP for big bluestem decreased as maturity increased. Microbial augmentation of RUP decreased as crude protein decreased in all species. The RUP corrected for acid detergent insoluble N and microbial protein was relatively constant across plant maturities. The quantification of RUP across a range of plant maturities provided information for incorporating RUP content of forage grasses into the diets of animals.(

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“…Johnson et al (2001) also reported a linear decrease (80 to 60 g kg −1 ) in bermudagrass Fraction C as N fertilization level increased from 0 to 156 kg ha −1 harvest −1 Warm‐season grasses tend to allocate protein compounds to chloroplasts. With a greater portion of chloroplasts located within the bundle sheath cells, the slower degradability of the bundle sheath cell wall may favor the enhancement of CP Fractions B and C without affecting Fraction A (Redfearn et al, 1995).…”

Section: Resultsmentioning

confidence: 99%

Protein Fractions of Tifton 85 and Rye‐Ryegrass Due to Sward Management Practices

Vendramini¹,

Sollenberger

Adesogan

et al. 2008

Agronomy Journal

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In the South, early weaned calves (Bos taurus) can be raised on pasture-based feeding programs, but to eff ectively meet their nutritional requirements, more information is needed on forage protein characteristics. Experiments were conducted from evaluate the eff ects of N fertilization and regrowth interval on crude protein (CP) fraction concentrations of rye (Secale cereale L.)-annual ryegrass (Lolium multifl orum Lam.) mixtures and 'Tift on 85' bermudagrass (Cynodon sp.). Treatments were the factorial combinations of three N levels (0, 40, and 80 kg ha -1 period -1 ) and two regrowth intervals, 3 and 6 wk for rye-ryegrass and 2 and 4 wk for bermudagrass. In situ digestibility methodology was used to describe CP fractions. For rye-ryegrass herbage CP, there was a linear increase in the concentration of Fraction A (rapidly degradable; 410-500 g kg -1 ) and a linear decrease in Fractions B (potentially degradable; 530-370 g kg -1 ) and C (undegradable in the rumen, 73-47 g kg -1 ) as N fertilization increased. For bermudagrass, Fraction B increased (330-455 g kg -1 ) and C decreased (283-208 g kg -1 ) linearly as N fertilization increased. High Fraction A concentration in rye-ryegrass CP favors use of supplements containing rumen-undegradable protein for early weaned calves. In contrast, large Fractions B plus C concentrations suggest that calves grazing bermudagrass may respond best to supplements containing rumen-degradable protein.

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Ruminal degradation of switchgrass, big bluestem, and smooth bromegrass leaf proteins

Cited by 24 publications

References 24 publications

Urea metabolism in beef steers fed tall fescue, orchardgrass, or gamagrass hays1,2

Urea metabolism in beef steers fed tall fescue, orchardgrass, or gamagrass hays1,2

Relationships Between In Situ Protein Degradability and Grass Developmental Morphology

Protein Fractions of Tifton 85 and Rye‐Ryegrass Due to Sward Management Practices

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