Relationships Between In Situ Protein Degradability and Grass Developmental Morphology

Mitchell, Robert B.; Redfearn, Daren D.; Moser, Lowell E.; Grant, Richard; Moore, Kenneth J.; Kirch, B.

doi:10.3168/jds.s0022-0302(97)76041-7

Cited by 18 publications

(16 citation statements)

References 15 publications

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“…It is not clear why there The RDP content of C3 was 28% greater (P < 0.01) and the RUP was 55% less (P < 0.01), as a percentage of total CP, than the RDP content of C4 (Table 2). This agrees with other data indicating that cool-season forages have a greater proportion of CP as RDP and less as RUP than do warm-season forages (Mullahey et al, 1992;Mitchell et al, 1997;Coblentz et al, 2004). These data increase the body of work suggesting that cool-season forages provide more rumen-available N for fermentation and microbial protein production than do warm-season forages.…”

Section: Expsupporting

confidence: 91%

See 1 more Smart Citation

Protein supplementation of ruminants consuming low-quality cool- or warm-season forage: Differences in intake and digestibility

Bohnert

DelCurto

Clark

et al. 2011

Journal of Animal Science

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An in situ study (Exp. 1) using 4 ruminally cannulated steers (343 ± 11 kg of BW) in a completely randomized design was used to compare ruminal degradation characteristics of low-quality cool-season (C3; Kentucky bluegrass straw; Poa pratensis; 6.3% CP; DM basis) and warm-season (C4; tallgrass prairie; 5.7% CP; DM basis) forage. Four ruminally cannulated steers (252 ± 8 kg of BW; Exp. 2) and 4 wethers (38 ± 1 kg of BW; Exp. 3) were used in two 2 × 2 factorial arrangements of treatments to determine the influence of supplemental CP (CPSupp; soybean meal; 0.09 and 0.19% of BW, CP basis, for steers and lambs, respectively) on nutrient intake and digestion of C3 and C4 forages. Steers and wethers were allotted to separate 4 × 4 Latin squares that ran simultaneously with 20-d periods. In Exp. 1, C3 had a greater A fraction (fraction of total pool disappearing at a rate too rapid to measure) and effective degradability of DM and NDF compared with C4 (P < 0.01). In addition, C3 had a greater (P < 0.01) A fraction and effective degradability of N, whereas the C fraction (fraction of total pool unavailable in the rumen) was less (P < 0.01) than those for C4. Consequently, RDP accounted for 84.7% of total CP in C3 as compared with 66% for C4 (P < 0.01). In Exp. 2, a CPSupp × forage interaction (P < 0.01) was noted for forage and total DMI, with CPSupp increasing intake of C4 by 47% and intake of C3 forage by only 7%. Dry matter digestibility responded similarly, with a CPSupp × forage interaction (P = 0.05; CPSupp increased digestibility by 21% with C4 and by 9% with C3 forage). In addition, CPSupp × forage interactions were noted for ruminal liquid retention time (P = 0.02; CPSupp decreased retention by 3.6 h with C4 and by only 0.6 h with C3 forage) and particulate passage rate (P = 0.02; CPSupp increased passage by 46% with C4 and by 10% with C3 forage). As in Exp. 2, a CPSupp × forage interaction (P = 0.01; CPSupp increased digestibility by 18% with C4 and by 7% with C3 forage) was observed with DM digestibility in Exp. 3. In contrast, only N balance (P < 0.01) and N digestibility (P < 0.01) were affected by CPSupp. These data suggest that intake and digestion of low-quality C3 and C4 forages by ruminants are not similar and, more important, that the physiological response of ruminants to protein supplementation of low-quality forage is dependent on forage type.

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Section: Expsupporting

confidence: 91%

“…There have been studies comparing the ruminai degradation characteristics of moderate-to high-quality C3 and C4 forages (Mertens and Loften, 1980;Mitchell et al, 1997;Coblentz et al, 2004), but to our knowledge, this is the first study that directly compared the ruminai degradation of low-quality (<6.5% CP) cool-and warm-season forages.…”

Section: Expmentioning

confidence: 94%

Protein supplementation of ruminants consuming low-quality cool- or warm-season forage: Differences in intake and digestibility

Bohnert

DelCurto

Clark

et al. 2011

Journal of Animal Science

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show abstract

“…As expected, the undegradable fraction [1)(a+b)] of CP increased with advanced stage of maturity (Table 7). The effective in situ degradation of CP decreased with advanced stage of maturity as also found in situ by Mitchell et al (1997) for different grasses, but values were only significantly different between the earliest and latest stage of development. Like previous results for DM, the NIRS predicted ED of CP was over-predicted in relation to in situ values, but values at each maturity stage were significantly different from one another.…”

Section: Discussionsupporting

confidence: 66%

Effective rumen degradation of dry matter, crude protein and neutral detergent fibre in forage determined by near infrared reflectance spectroscopy

Ohlsson¹,

Houmøller²,

Weisbjerg³

et al. 2007

Animal Physiology Nutrition

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The objective of the present study was to examine if near infrared reflectance spectroscopy (NIRS) could be used to predict degradation parameters and effective degradation from scans of original forage samples. Degradability of dry matter (DM), crude protein (CP) and neutral detergent fibre (NDF) of 61 samples of perennial ryegrass (Lolium perenne L.) and orchardgrass (Dactylis glomerata L.) was tested by using the in situ technique. The grass samples were harvested at three different stages, early vegetative growth, early reproductive growth and late reproductive growth. Degradability was described in terms of immediately rumen soluble fraction (a fraction, for DM and CP only as NDF does not contain a soluble fraction), the degradable but not soluble faction (b fraction) and the rate of degradation of the b fraction (c value). Overall effective degradability of DM, CP and NDF was also calculated. Near infrared reflectance spectroscopy was examined for its ability to predict degradation parameters and to make a direct prediction of effective degradation from scans of the original samples of perennial ryegrass and orchardgrass. Prediction of effective degradation of the different feed fractions showed different accuracy. The coefficients of determination (R(2)) from regressions of predicted vs. measured effective degradation, using a cross-validation method, were 0.92 for DM, 0.78 for CP and 0.61 for NDF. The attempt to predict the degradation parameters (a, b and c) by NIRS was less successful as the coefficients of determination for the degradation parameters were low. Concentrations of CP and NDF in the original samples were predicted by using NIRS and the validated R(2) value was 0.98 for CP and 0.92 for NDF. It is concluded that using NIRS predictions from scans of original samples is a promising method to obtain values for the effective degradation of DM, CP and NDF in ruminant feeds, but that larger calibration sets are necessary for obtaining improved accuracy.

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“…Furthermore, relatively small changes in RUP pools for maturing plants have been reported previously. Mitchell et al (1997) reported that RUP concentrations for smooth bromegrass ( Bromus inermis Leyess.) and intermediate wheatgrass [ Thinopyrum intermedium (Host) Barkworth and D.R.…”

Section: Discussionmentioning

confidence: 99%

Harvest Timing Effects on Estimates of Rumen Degradable Protein from Alfalfa Forages

et al. 2008

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Alfalfa (Medicago sativa L.) proteins ingested by dairy cows typically degrade at rapid rates and exhibit extensive ruminal degradability. Although the effects of conservation method (hay or silage) on these characteristics have been evaluated extensively, agronomic factors, such as harvest timing, have not. Our objective was to quantify rumen degradable protein (RDP) for ‘Affinity’ alfalfa harvested over a range of ages (0, 5, 10, 15, and 20 d following Stage 2) within each of four harvest periods (spring, early and late summer, and fall). For 2004, there were no interactions (P ≥ 0.372) between harvest period and days within harvest period for any protein component. Crude protein (CP), neutral‐detergent soluble CP (NDSCP; g kg−1 dry matter [DM]), and RDP (g kg−1 DM) declined in a quadratic (P ≤ 0.026) relationship with days following Stage 2. A quadratic (P = 0.002) pattern also was observed for rumen undegradable protein (RUP), but the overall range was small (60.4–66.5 g kg−1 DM). On a CP basis, RDP declined linearly (P < 0.001) from 720 to 659 g kg−1 CP during 2004. For 2005, there were interactions (P ≤ 0.020) of harvest period and days within period for all protein‐related response variables, but trends over time within each harvest period generally were similar to those observed in 2004. Overall, RDP declined as alfalfa plants aged within harvest period, but these responses were due pri marily to reduced concentrations of CP within the cell‐soluble fraction.

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Relationships Between In Situ Protein Degradability and Grass Developmental Morphology

Cited by 18 publications

References 15 publications

Protein supplementation of ruminants consuming low-quality cool- or warm-season forage: Differences in intake and digestibility

Protein supplementation of ruminants consuming low-quality cool- or warm-season forage: Differences in intake and digestibility

Effective rumen degradation of dry matter, crude protein and neutral detergent fibre in forage determined by near infrared reflectance spectroscopy

Harvest Timing Effects on Estimates of Rumen Degradable Protein from Alfalfa Forages

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