Crude Protein Concentration Of Herbage Research Articles

In situ dry matter and crude protein disappearance dynamics in stockpiled limpograss

AbstractStockpiling warm‐season perennial grasses for winter grazing is an important management practice for beef cattle production systems in tropical and subtropical regions. Limpograss [Hemarthria altissima (Poir.) Stapf et C.E. Hubb.] has greater digestibility at late maturity than other commonly used warm‐season perennial grasses; however, decreased crude protein (CP) concentration may limit livestock performance. The objective of this study was to evaluate the in situ dry matter (DM) and CP ruminal disappearance kinetics of stockpiled limpograss herbage. Forage for the in situ study derived from a 2‐yr field experiment in which treatments were the factorial combinations of three cultivars (‘Kenhy’, ‘Gibtuck’, or ‘Floralta’) and three stockpiling periods (8, 12, or 16 wk) distributed in three replicates of a randomized complete block design. Effective degradability of DM was greater for Kenhy and Gibtuck compared with Floralta (614 and 611 vs. 575 g kg−1), and it declined linearly as stockpiling period increased from 8 to 16 wk (623 vs. 586 g kg−1). Herbage CP concentration (48–32 g kg−1 DM) also declined linearly from 8 to 16 wk, but rumen‐unavailable CP increased during stockpiling (257–438 g kg−1 CP), causing effective CP degradability to decrease (637–489 g kg−1 CP). Limpograss is a good option for stockpiled forage, and both new releases outperformed Floralta; however, concentration and availability of CP must be considered when defining a supplementation strategy.

Nutritive value of herbage of five semi‐irrigated pasture species across an irrigation gradient

AbstractAs water resources become limiting, the need to produce stable amounts of herbage with a high nutritive value increases. An understanding of how levels of irrigation affect crude protein (CP) and neutral‐detergent fibre (NDF) concentrations and, in vitro true digestibility (IVTD), is critical in the management of pastures. Smooth bromegrass (Bromus inermis Leyss.), prairiegrass (Bromus willdenowii Kunth), hybrid‐bromegrass [meadow (Bromus riparius Rehm.) × smooth bromegrass], creeping foxtail (Alopecurus arundinaceus Poir.) and RS wheatgrass (Elymus hoffmannii Jensen & Asay) were established under a line‐source irrigation system to evaluate the effect of five water levels and three harvest dates on concentrations of CP and NDF, and values of IVTD. With CP concentration of herbage, there were positive linear significant relationships with decreasing water levels for all species. Rankings for mean CP concentrations across water levels and harvest dates were smooth bromegrass > RS wheatgrass > hybrid‐bromegrass > creeping foxtail > prairiegrass. No consistent relationships with IVTD across water levels were detected among the species. Averaged across water levels, harvest dates and years, smooth bromegrass, hybrid‐bromegrass and creeping foxtail had significantly higher IVTD values than RS wheatgrass and prairiegrass. Rankings of mean NDF concentrations across water levels and harvest dates combined over years were prairiegrass > RS wheatgrass > hybrid‐bromegrass > creeping foxtail > smooth bromegrass. Herbage of smooth bromegrass had higher IVTD values and lower NDF concentrations than hybrid‐bromegrass, prairiegrass, creeping foxtail and RS‐hybrid at all water levels.

How does protein supplementation affect the selectivity and performance of Charolais cows on extensively grazed pastures in late autumn?

AbstractManagement of beef cows grazing extensively grazed semi‐natural pastures in temperate regions in late autumn can require supplements to be offered. The effects of supplementation with soya bean meal on the diet selected by Charolais cows and on their subsequent performance were examined for an 8‐week period in late autumn in 2 years. Three groups of eight cows were compared: non‐supplemented dry cows (D), non‐supplemented (L) and supplemented (LS) lactating cows. The amount of soya bean meal supplement offered per cow was 250 g d−1 in year 1 and 800 g d−1 in year 2. Dietary choices were measured by direct observations and herbage intake was estimated in year 2. Supplementation affected neither diet selection (L: 0·42 vs. LS: 0·43 for the proportion of bites on green patches in year 1; 0·24 vs. 0·22 in year 2) nor daily organic matter intake of herbage (L: 15·6 vs. LS: 15·9 kg d−1), which may have resulted from an adequate crude protein concentration of herbage. The higher total dry matter intake by cows offered the supplement reduced losses in live weight (L: −1212 vs. LS: −828 g d−1; P < 0·01) rather than increased milk production (L: 5·1 vs. LS: 5·0 kg d−1). This may be linked to the low milk yield potential of the Charolais cows. The use of lactating cows rather than dry cows for pasture management in late autumn would increase the utilization of herbage but a reduction in liveweight losses of cows by supplementation is unlikely to be economic.

Performance of spring-calving beef suckler cows and their progeny to slaughter on intensive and extensive grassland management systems

The performance of rotationally grazed beef suckler cows and their progeny to slaughter on two lowland grassland management systems differing in stocking rate (SR) and fertiliser nitrogen (N) level was compared over eight years. The two Systems were 1) Intensive (INT): SR of 0.56 (bull production) or 0.71 (steer production) ha cow − 1 unit, 211 kg fertiliser N ha − 1 , two silage harvests, and 2) Extensive (EXT): SR of 0.69 (bull production) or 0.88 (steer production) ha cow − 1 unit, 97 kg fertiliser N ha − 1 and one staggered silage harvest. A cow unit was defined as a cow plus progeny to slaughter. On the silage harvesting area, the mean application rate for fertiliser N was 110 and 80 kg ha − 1 for first and second harvests, respectively. Herbage dry matter digestibility both pre- and post-grazing was similar ( P > 0.05) for the two systems, whereas herbage crude protein concentrations were generally significantly lower for the EXT than the INT system. There was no difference ( P > 0.05) between the Systems in cow live weight, body condition score or their changes or in calf live weight gain from birth to weaning. Post-weaning, live weight gain, slaughter weight, carcass weight, kill-out proportion, estimated carcass gain, carcass conformation score or carcass fat score did not differ ( P > 0.05) between the systems for heifer, steer or bull progeny. It can be concluded that similar animal performance levels can be expected in an extensive grassland-based suckler calf-to-beef system compatible with the EU, Rural Environmental Protection Scheme as that attained in a more intensive System comprising of both a moderately high SR (~ 1.25 higher) and fertiliser N application (~ 2.1 higher).

Manipulation of herbage production by altering the pattern of applying nitrogen fertilizer

AbstractThe redistribution of herbage production during the growing season to synchronize herbage supply with feed demand by livestock by altering the application pattern of a range of nitrogen (N) fertilizer rates was studied. Application rates of N were 50, 150 and 250 kg N ha−1 per annum and patterns were with 0·60 of N fertilizer applied before June (treatment RN) and with only 0·20 of N fertilizer before June (treatment IN). Treatments were imposed in a cutting (simulated grazing) experiment (Experiment 1), which was conducted for 2 years and a grazing experiment (Experiment 2) which was conducted for 3 years. In both experiments, herbage production was reduced in April and May and increased in the June–October period on treatment IN relative to RN, but annual herbage production was not significantly affected except in the third year of Experiment 2, when treatment RN had significantly (P < 0·05) higher herbage production than treatment IN. Crude protein (CP) concentration of herbage was lower in April and May on treatment IN than treatment RN. However, CP concentration of herbage was rarely below 150 g kg−1 DM and so it is unlikely that livestock productivity would be compromised. On treatment IN, concentrations of CP in herbage were higher in the late summer than on treatment RN, which may increase livestock productivity during July and August when livestock productivity is often lower. Altering the strategy of application of N fertilizer did not affect in vitro dry matter digestibility of herbage.

Influence of solar radiation on the productivity and nutritive value of herbage of cool‐season species of an understorey sward in a mature conifer woodland

AbstractSilvopastoral systems in the Appalachian region of the USA could increase the carrying capacity of livestock and contribute to a reliable supply of high‐quality herbage. In 2000, 2001 and 2002, the influence of solar radiation [0·20, 0·50 or 0·80 of maximum solar radiation (MSR); treatments 20‐, 50‐ and 80‐MSR respectively] on the productivity and nutritive value of a mixture of sown grasses and legumes established under a mature stand of conifers was investigated. Yields of dry matter (DM), crude protein (CP), total non‐structural carbohydrates (TNC) and total digestible nutrients (TDN) were greater for the 80‐MSR treatment except in 2000 when DM yield did not differ. As a proportion of the sward, introduced species (Dactylis glomerata L., Trifolium repens L., and Lolium perenne L.) increased over time for the MSR‐80 treatment, corresponding with a decrease in the proportion of bare area and of non‐introduced species. CP concentration of herbage was 207 g kg−1 DM or greater across treatments and years with higher concentrations on the 20‐ and 50‐MSR treatments. Herbage from the 80‐MSR treatment had a greater concentration of TNC than that of the 20‐ and 50‐MSR treatments. Estimated concentration of TDN was similar for all treatments in 2000 and greater for the 80‐MSR treatment than the other two treatments in 2001 and 2002. High CP concentrations in herbage, as a result of appropriate thinning of trees in an Appalachian silvopastoral systems, could be utilized as a protein supplement to herbage with low CP and higher fibre concentrations.

Herbage mass, nutritive value and canopy spectral reflectance of bermudagrass pastures

AbstractTimely and accurate detection of above‐ground herbage mass and the nutritive value of pastures can help the more efficient adjustment of stocking rate and determine the timing of protein supplements to be fed to livestock grazing these pastures. The objectives of this study were to determine seasonal variation in herbage mass, neutral‐detergent fibre (NDF), acid‐detergent fibre (ADF) and crude protein (CP) concentrations of herbage and canopy reflectance of pastures of genotypes of bermudagrass (Cynodon dactylon L.), and to analyse the relationships between these descriptors of nutritive value of herbage and canopy reflectance in broad spectral wavebands. Three bermudagrass pastures of varieties Midland and Ozarka, and an experimental hybrid, 74 × 12‐12, were established in 1991 and had received the same field management and stocking rate. Canopy reflectance, above‐ground herbage mass of DM and CP, and NDF, ADF and CP concentrations of herbage were measured in the growing seasons of 2002 and 2003. Year, genotype and sampling date significantly (P < 0·05) affected most measured variables. Ratios of canopy reflectance in blue to red (R(blue)/R(red)) and in near infrared to red (R(NIR)/R(red)) wavebands were highly correlated with concentrations of CP in herbage and herbage mass of CP but the relationships between reflectance ratios and NDF and ADF concentrations of herbage were relatively low. It is concluded that the CP concentration of herbage and herbage mass of CP of pastures can be estimated throughout the growing season using remote sensing of canopy reflectance and the information may be used for pasture and livestock management.

Spring Lamb Production on Alfalfa, Sainfoin, and Wheatgrass Pastures

AbstractLamb (Ovis aries) weight gains from wheatgrass‐sainfoin (Agropyron and Thinopyron spp.‐Onobrychis viciifolia Scop.) mixtures suggest that grazing sainfoin monocultures offers advantages over mixtures. Our objective was to determine levels of spring lamb production from irrigated ‘Renumex’ sainfoin, ‘Cimmaron’ alfalfa (Medicago sativa L.), ‘Luna’ pubescent wheatgrass [T. intermedium subsp. barbulatum (Schur) Barkw. & D.R. Dewey], and pubescent wheatgrass‐sainfoin pastures. Replicated pastures grown on a fine, mixed, thermic Torrertic Paleustoll were rotationally stocked (herbage dry matter [DM] allowance of 6.5% of body wt. d−1) by weaned Rambouillet ✕ Suffolk wether lambs for an average of 88 d in spring of 1991 and 1992. Across years, cumulative weight gain (CWG) ranged between 7.9 kg lamb−1 for wheatgrass and 16.4 kg lamb−1 for alfalfa. In 1991 (avg. 16.1 kg lamb−1) and 1992 (avg. 12.3 kg lamb−1) CWG for alfalfa and sainfoin was similar. Lamb production per hectare (PROD) was greatest for legumes (808 kg lamb ha‐1) and least for wheatgrass (533 kg lamb ha−1). Including sainfoin with wheatgrass increased PROD by 23% over wheatgrass, whereas sainfoin alone increased PROD by 25% over the mixture. Intake of sainfoin herbage (1.5 kg DM lamb‐unit‐1 d‐1) was 29% greater than of alfalfa, wheatgrass, or wheatgrass‐sainfoin (1.2 kg DM lamb‐unit−1 d−1, where 1 lamb‐unit is a 35‐kg lamb). Herbage crude protein concentrations (pregrazing) were highest for alfalfa (253 g kg−1) and lowest for wheatgrass (159 g kg−1). Sainfoin had the lowest organic matter digestibility (641 g kg−1), which did not reflect the high CWG or PROD obtained. Alfalfa or sainfoin offer greater opportunities for spring lamb production than wheatgrass or wheatgrass‐sainfoin pastures.

Water‐Deficit Effects on Alfalfa at Various Growth Stages

AbstractStudies of water‐deficit effects on forage quality of alfalfa (Medicago sativa L.) have generally considered water stress throughout plant growth. This experiment was conducted to compare, with an unstressed control, the effects of short‐term soil‐water deficits occurring at three growth stages. Plants were grown in 100‐L containers set into the ground and protected with an automatic rain‐out shelter. Control treatments were watered weekly or twice weekly to raise the soil‐water level to field capacity. Watering was excluded during the third or fourth week of regrowth for plants that were stressed at vegetative and bud stages, respectively. For plants stressed at the flower stage, watering was excluded during the sixth or seventh week. Plants were harvested at five weekly intervals beginning 21 d after an initial defoliation. Stress at the bud or flower stages reduced leaf‐to‐stem ratio (LSR) by 25 and 38% of control, respectively. Stress at the vegetative stage did not affect LSR. As a result of lower LSR, in vitro digestible dry matter (IVDDM) in plants stressed at the bud or flower stages was 4% less than that of the control. The IVDDM of herbage in plants stressed at the vegetative stage was not different from the control. Crude protein (CP) concentration in stems increased by up to 8% of the control when plants were stressed at the vegetative or bud stages. Concentration of CP in leaves of stressed plants was 5 to 11% less than that of the control. Herbage CP concentration was up to 12% less than that of the control with stress at the bud or flower stages. Cell wall (CW) concentration in stems and total herbage was generally lower in plants stressed at the vegetative and bud stages. After rewatering, forage quality recovered in plants stressed at the bud stage. Most of the decline in forage quality due to stress at the bud or flower stages was caused by reduction in LSR and deterioration of leaf quality.

Cicer Milkvetch and Alfalfa as Influenced by Two Cutting Schedules1

AbstractCicer milkvetch (Astragalus cicer L.) is a promising forage legume, but little is known about its response to cutting. A 2‐year study was conducted at Fort Collins, CO, on a Nunn clay loam (fine, montmorillonitic, mesic Aridic Argiustoll) soil to compare yield, quality, and trends in carbohydrate reserves of cicer milkvetch and alfalfa (Medicago sativa L.) in response to annual three‐ and four‐cut clipping treatments. Quality was evaluated by determining concentrations of crude protein (CP) and cell wall constituents (CWC) in herbage from each harvest. Seasonal dry matter yields of alfalfa were similar under both clipping treatments during each year. Yields of cicer milkvetch were reduced under the more frequent cutting schedule in 1979, but not in 1980. During 1979, quality differences between the clipping treatments were apparent for alfalfa but not for cicer milkvetch. Improved quality, as measured by increased CP and decreased CWC concentrations, was observed in herbage from both species under the more frequent clipping treatment in 1980. Herbage CP concentration was simiilar under comparable clipping treatments during both years, however, the CWC concentration of cicer milkvetch was consistently lower than that of alfalfa. Cyclic trends in carbohydrate reserves were observed in alfalfa under both clipping treatments in 1980, but only under the three‐cut treatment in 1979. Carbohydrate reserve trends in cicer milkvetch roots and rhizomes were less cyclic than in alfalfa and similar under both cutting schedules each year. Carbohydrate reserve concentrations in all forage entries were similar at the end of the 1980 growing season regardless of clipping treatment. Following cutting, carbohydrate reserves in alfalfa were readily utilized during the initial period of recovery. Carbohydrate reserves in cicer milkvetch appeared to be actively involved in regrowth processes only when little, or no, residual leaf area remained after cutting.