Forage Nutritive Value Research Articles

Application of poultry litter and moisture effects on rye–ryegrass–fescue baleage

AbstractSubsurface poultry litter application improves nutrient utilization compared with surface application through reduced nutrient runoff, and increased forage nutritive value. This study compared the effects of subsurface (SUB) or surface (SURF) poultry litter application against controls (CON; no litter) for baled silages made at high moisture (HM) or low moisture at (LM) Booneville, AR, in 2018. Mixtures of cereal rye (Secale cereale L.), annual ryegrass (Lolium multiflorum Lam.), and tall fescue [Schedonorus arundinaceus (Schreb.) Dumort., nom. cons.] baled silages were compared for nutritive value and silage fermentation characteristics. Data were analyzed as a split‐plot design with three fertilizer treatments as whole plots, and initial bale moisture as subplots. Pre‐ensiled P and K were greater (P < .05) for the mean of SURF and SUB than for CON. Neutral detergent fiber was greater (P = .02) in CON versus the mean of SURF and SUB. In post‐ensiled bales, propionic (P < .05) and succinic acid (P < .05) concentrations were greater in the mean of SURF and SUB than in CON, and greater in SUB than in SURF. Moisture had positive (P < 0.05) relationships with fermentation acids, and negative relationships with pH, water‐soluble carbohydrates, and starch. Overall, very few differences between SUB and SURF were detected, baleage nutritive value was not improved with SUB poultry litter application, and fermentation characteristics were most affected by the initial bale moisture.

Grass-legume intercropping for sustainability animal production in the tropics

Abstract Seasonal and low forage availability and quality, shrinking of grassland area, and poor grassland management are the main causes of low soil fertility and animal production in tropical grasslands. One sustainable way to overcome the problems is through establishment of grass-legume intercropping in tropical grassland. Results revealed that grass-legume intercropping improved soil health and fertility, forage yield, and stability and reduced weed invasion. Besides, it improves forage nutritive value and animal production. To enhance grass-legume intercropping, the selected grass and legume species should be matched with local environmental conditions followed by good management.

Floristic Composition Mediates Change in Forage Nutritive Quality of Atlantic Mountain Grasslands after Experimental Grazing Exclusion

Simultaneous reduction of biodiversity and forage nutritive value after grazing abandonment represents a critical agroecological problem observed in temperate mountain grasslands. However, how both processes affect each other after the exclusion of large grazers is not well understood. To address this knowledge gap, we used four Atlantic grassland sites in the Aralar masif (northern Iberian Peninsula) to ask whether floristic composition mediates change in forage nutritive quality after grazing exclusion, and, if so, how much of the effect on forage quality is mediated. To examine the effects of grazing exclusion on forage quality and floristic composition a repeated-measures (2005–10) randomized complete block experiment was used. Then, the direct effects of grazing exclusion on forage quality were disentangled from the indirect effects mediated by concurrent change in floristic composition. Grazing exclusion deteriorated forage mineral content, phosphorus content, neutral detergent fiber and, especially, crude protein and enzymatic digestibility. Concurrent floristic change mediated change in crude protein (80%), enzymatic digestibility (55%) and forage content in calcium (31%). Our study shows that plant diversity and forage quality are intimately linked features of Atlantic mountain grasslands and highlights the importance of preserving leguminous and dicotyledonous species to maintain the nutritive value of these grasslands.

Changes in forage nutritive value of reduced‐lignin alfalfa during regrowth

AbstractGenetically engineered alfalfa (Medicago sativa L.) cultivars with reduced lignin (RL) concentration are commercially available but their change in nutritive value as the crop matures within a growth cycle has not been thoroughly documented and might differ from non‐RL cultivars. This research documents changes in forage nutritive value of a RL cultivar (HarvXtra‐008) and two non‐RL cultivars (54R02 and WL355RR) within five growth cycles across 2 yr in six states in the United States. A randomized complete block design with a split‐plot arrangement of treatment randomization was used, with harvest growth cycles assigned to whole plots and cultivars to subplots in field trials. Cultivars were sampled on 3‐ to 4‐d intervals between day 20 and 37 of regrowth. HarvXtra‐008 was consistently lower (P ≤ .05) in acid detergent lignin (ADL) by 7–10% and amylase‐treated neutral detergent fiber (aNDF) by 2–10% and 4–9% greater (P ≤ .05) in neutral detergent fiber digestibility (NDFD) than non‐RL cultivars across all sampling dates. Cultivar × regrowth duration interactions (P ≤ .05) were found only for ADL and aNDF in two of the five growth cycles sampled, when regression coefficients were always smaller for HarvXtra‐008 than 54R02. We calculated that the interval between harvests can be extended on average from 8 to 11 d for HarvXtra‐008 compared with non‐RL cultivars while maintaining adequate fiber digestibility for animals with high nutritional requirements; however, the extent of that longer harvest interval varied from 2 to 20 d depending on environmental conditions.

Impact of different nutrient sources on forage yield, nutritive value and economics of sorghum sudan grass hybrid-Oat cropping system

It is imperative to develop integrated fertilization strategies for various forage crops that enhance the competitive ability of the crop, increase crop production and reduce the risk of nonpoint source pollution from fertilizers. The objectives of this study were to determine the effect of different sources of nutrients on performance of sorghum sudan grass hybrid-oat cropping system. Significantly highest plant height, shoots per square meter, leaf stem ratio and dry matter accumulation of sorghum sudan grass hybrid and oat was observed with FYM @10 t ha−1+Azotobacter+PSB. Not surprisingly, plant height, shoots per square meter, leaf stem ratio and dry matter accumulation increased with increasing fertilizer levels with highest values recorded with 100% RDF. Moreover, significantly highest total green and dry forage yields and gross as well as net returns were recorded in FYM @10 t ha−1+Azotobacter+PSB as well as 100% RDF. FYM @10 t ha−1+Azotobacter+PSB resulted in higher benefit cost ratio, while, significantly highest benefit cost ratio was also recorded with 100% RDF. The system productivity and production efficiency showed its maximum value in FYM @10 t ha−1+Azotobacter+PSB as well as highest level of NPK fertilization.

Forage Yield and Nutritive Value of Cool-Season and Warm-Season Forages for Grazing Organic Dairy Cattle

The objective of this study was to compare the forage nutritive value of cool-season perennial grasses and legumes with that of warm-season annual grasses grazed by organic dairy cows. Two pasture systems were analyzed across the grazing season at an organic dairy in Morris, Minnesota. Pasture system 1 included perennial ryegrass (Lolium perenne L.), orchardgrass (Dactylis glomerata L.), meadow bromegrass (Bromus riparius Rehmann), meadow fescue (Schedonorus pratensis (Huds.) P. Beauv), alfalfa (Medicago sativa L.), white clover (Trifolium repens L.), red clover (Trifolium pratense L.), and chicory (Cichorium intybus L.). Pasture system 2 was a combination of system 1 and monocultures of warm-season grasses (sorghum-sudangrass (Sorghum bicolor [L.] Moench subsp. drummondii [Steud.]) and teff (Eragrostis tef L.)). Across the grazing season, forage yield was 39% greater for system 2 than system 1 due to greater forage yield during the summer. Neutral detergent fiber (NDF) and acid detergent fiber (ADF) were similar for cool-season and warm-season grasses. Warm-season grasses had greater forage yield during the summer months compared with cool-season grasses and legumes. The total tract NDF digestibility (TTNDFD) varied by month and year across the study for both pasture systems. Overall, weather may affect the forage nutritive value for both cool-season perennial grasses and legumes and warm-season annual grasses.

Impact of long-term manure and mineral fertilization on yield and nutritive value of lucerne (Medicago sativa) in relation to changes in canopy structure

Fertilization management influences not only productivity but also the nutritive value of forage legumes. However, there have been few studies about these effects in long-term fertilization experiments. Our objectives were: (i) to compare the effects of mineral fertilization and organic manure on lucerne forage yield and leaf and stem nutritive value over a 2-year period following 60 years of different fertilization managements, and (ii) to investigate relationships among canopy structure traits and forage nutritive value in association with these fertilization treatments. The long-term fertilization experiment was established with four replications in the Czech Republic in 1955. Three levels of mineral N, P and K application (0:0:0, 39:24:109 and 91:31:146) were investigated, each with and without farmyard manure, resulting in six treatments. Lucerne stands were established in 2012 and 2013 in two strips. Forage yield was measured in two cuts in 2014 and 2015, respectively. Canopy structure traits and forage nutritive value (crude protein, ash, neutral detergent fibre (NDF) and NDF digestibility (NDFD) were analysed in the first cut in each year. Intensive mineral fertilization reduced lucerne nutritive value through a reduction in stem NDFD (-6%) and leaf weight ratio (-10 %) under higher forage productivity (+10 % of annual yield). Manure fertilization improved nutritive value of leaves and stems, with an associated increase in whole plant nutritive value as leaf proportion was maintained with increased yield (+8%). This positive response could be attributed to a soil environment effect: greater root development in soil that had received long-term manure fertilization probably reduced forage lignification and maintained leaf proportion in association with reduced drought stress. Long-term manure fertilization demonstrated potential for improvement of lucerne nutritive value despite the negative relationships between increased plant growth under higher nutrient supply and forage nutritive value.

20 Comparison of native warm-season grasses and bermudagrass for stocker calf grazing in the Black Belt Prairie region

Abstract Native grasses are touted for use in drought mitigation strategies for grazing cattle. It is important to determine how these forages compare in specific production environments to more widely used improved grasses such as bermudagrass [Cynodon dactylon (L.) Pers.] that they may replace as pasture. Native warm-season grasses including big bluestem (Andropogon gerardi Vitman), little bluestem (Andropogon scoparius), and indiangrass (Sorghastrum nutans L.) were evaluated against bermudagrass pastures in the Black Belt Prairie region of Mississippi for stocker cattle grazing. Objectives were to compare bermudagrass (BG), indiangrass (IG) and mixed-sward native warm-season grass (mix of big bluestem, little bluestem, and indiangrass) (NGMIX) pasture for forage nutritive value and steer ADG. Crossbred (Bos taurus) steers (n = 36 steers/year) were stratified by initial BW (339.7 ± 4.3 kg) to 2.02-ha pastures (3 replications) during 56-d grazing periods in June and July for 2 yr. Mean forage nutritive values on a DM basis were: BG [8.8% CP, 43.4% ADF, 67.3% NDF, 58.7% TDN, and 77 relative feed value (RFV)], IG (6.7% CP, 39.6% ADF, 68.3% NDF, 58.2% TDN, and 79 RFV) and MIXNG (7.3% CP, 40.5% ADF, 69.5% NDF, 58.1% TDN, and 77 RFV). A forage treatment x day x year effect existed (P < 0.01) for each these nutritive values. There was no effect (P = 0.47) of forage treatment on steer ADG (BG: 0.4 ± 0.1 kg/d; IG: 0.5 ± 0.1 kg/d; NGMIX: 0.5 ± 0.1 kg/d). Thus, no net advantage or disadvantage in steer growth rates was observed due to forage species. Other factors such as forage establishment cost and animal stocking rates supported may be relevant to consider in decisions to replace bermudagrass with warm-season native grasses.

87 Evaluation of two stocking rates for grazing heifers on mixed sward native warm-season grass pastures in the Black Belt Prairie region

Abstract Optimal use of native warm-season grasses in pasture systems involves stocking grazing livestock at suitable rates. The study objective was to evaluate forage nutritive value and heifer ADG at two stocking rates on mixed-sward pastures of big bluestem (Andropogon gerardi Vitman), little bluestem (Andropogon scoparius), and indiangrass (Sorghastrum nutans L.). Pastures (3 replications) were stocked for 56 d during June and July in 2 yr with crossbred (Bos taurus) heifers (n = 24 heifers/year) stratified by initial BW (288.3 ± 1.7 kg) to one of two continuous stocking rates: 1.9 heifers/ha (HIGH) and 1.2 heifers/ha (LOW). Mean forage nutritive values on a DM basis were not different between HIGH and LOW stocking rates, respectively, for CP (7.0 ± 0.2% vs 6.7 ± 0.2%; P = 0.27), ADF (41.0 ± 0.6 vs. 41.4 ± 0.6; P = 0.64), NDF (69.9 ± 0.5 vs. 68.7 ± 0.5; P = 0.09), or relative feed value (RFV) (76.0 ± 1.0 vs. 76.9 ± 1.0; P = 0.53). There was a year effect (P < 0.01) and stocking rate x day effect (P < 0.01) for TDN. At LOW, TDN decreased from day 0 to day 28 (P = 0.02) and day 28 to day 56 (P = 0.02). At HIGH, TDN decreased (P < 0.01) from day 0 to day 28 but remained steady until day 56 (P = 0.21). There was a stocking rate x day interaction (P < 0.01) with ADG: LOW day 28 to 56 (1.20 ± 0.08 kg/day), HIGH day 0 to 28 (0.89 ± 0.08 kg/day), HIGH day 28 to 56 (0.44 ± 0.08 kg/day), and LOW day 0 to 28 (0.30 ± 0.08 kg/day). Further assessment of cattle ADG using more divergent stocking rates and plant persistence measures is warranted to inform ideal native grass stocking rate recommendations.

111 Metsulfuron and variable nitrogen application rates on infected tall fescue: effects on stocker performance, forage yield, nutritive value, ergovaline concentration and botanical composition

Abstract Chemical seed-head suppression of endophyte infected tall fescue (Lolium arundinaceum) improves stocker cattle performance but may decrease forage yield. Spring nitrogen application increases tall fescue growth with a concomitant increase in ergot alkaloids, produced by the symbiotic endophyte Epichloë coenophiala. We hypothesized that greater amounts of nitrogen applied to tall fescue would increase forage yield and offset losses in forage production from chemical suppression of seed-heads with metsulfuron without effect on alkaloid concentration. Ninety-six steers (270 ± 20 kg) were randomly assigned to one of sixteen paddocks (1.8 ha) on April 18 and continuously grazed for 57 d. Paddocks were blocked by previous use (n = 4) and randomly assigned to one of four treatments; no metsulfuron, no nitrogen (NEGCON), metsulfuron with 0 (MET0), 67 (MET67), or 134 (MET134) kg/ha of ammonium nitrate, applied March 11. Steers grazing MET0 paddocks were removed 17 d early due to insufficient forage availability. Steer weight, forage yield, forage nutritive value and ergot alkaloids in forage samples were measured monthly. Seed-head frequency and species composition were determined in June. Metsulfuron application reduced (P < 0.01) tall fescue seed-heads by 80%. Metsulfuron decreased (P = 0.03) ergovaline but ergovaline increased (P < 0.01) at each monthly sampling across treatments. Nitrogen had no impact on ergovaline concentration (P = 0.50). Forage yield tended to be least (P = 0.07) for MET0, intermediate for NEGCON and MET67, and tended to be greatest for MET134 (P = 0.08). Steer ADG was not affected by treatment (P < 0.80). Metsulfuron decreased NDF (P=0.02) regardless of fertilization rate. Forage CP increased with fertilization (P < 0.01) and no differences were detected between NEGCON and MET0 (P = 0.45). Species composition was not impacted (P >0.07) by treatment. Metsulfuron decreased seed-head growth and ergovaline concentration in tall fescue. Additional nitrogen fertilizer ameliorated forage yield lost to metsulfuron application but did not impact steer gain.

115 Nitrogen fertilizer effects on above ground sward characteristics and beef heifer performance from native warm-season grass blends

Abstract A 2-yr study was conducted at Black Belt Research and Extension Center in Marion Junction, AL, to evaluate the effect of nitrogen (N) fertilizer application rate on forage production characteristics, nutritive value, and animal performance of beef heifers grazing a mixture of native warm-season grasses (NWSG) including big bluestem, little bluestem, and indiangrass. Six, two-hectare plots were randomly assigned to one of two treatments (0 or 67 kg N ha-1 applied in early April; n = 3 replications per treatment). Paddocks were continuously stocked with four weaned Angus × Simmental beef heifers (initial BW 288 ± 7 kg) from late May/early June through mid-to-late August during 2018 (73 grazing d) and 2019 (70 grazing d), respectively. Put-and-take cattle were used to manage forage to a target of 38 cm. Forage mass and canopy heights were collected every two weeks during the trial. Visual ground cover ratings, canopy light interception, and botanical composition were measured at the beginning and end of the trial in each year. Hand-plucked samples were collected every two weeks during the grazing trial to determine forage nutritional value. Data were analyzed using the PROC MIXED procedure in SAS 9.4, and differences were declared significant when P ≤ 0.05. Nitrogen fertilized NWSG had greater crude protein (P < 0.0001), sward heights (P = 0.0003), and canopy light interception at the beginning of the season (P = 0.0049) compared to non-fertilized paddocks. However, there were no differences (P ≥ 0.05) among N-fertility treatments for mean forage mass, heifer ADG, or BCS across the 2-yr study. Botanical composition data indicated that indiangrass decreased from 64% to 61% (P = 0.0022) and weed pressure increased from 11% to 15% (P = 0.0064) across the summer grazing season. Canopy light interception decreased by 51% from early June to August in fertilized NWSG and 26% in unfertilized paddocks, respectively. These data illustrate that NWSG systems may provide a viable grazing system in the summer months under reduced N inputs.

The evaluation of warm-season annual grasses as alternative sources of forage crops for beef cattle diets under northwestern Alberta conditions

ABSTRACT In recent years, there has been considerable interest in growing warm-season crops in monocultures and in mixtures for beef cattle production. The objective of this investigation was to measure the forage yield and nutritive value for the beef diet of 10 C4 and two C3 forage-type cereal crops. Forage yield was greater (P < 0.05) for C3 than C4 crops. The C4 crops generally had greater forage crude protein (CP) and total digestible nutrient (TDN) values comparable to C3 crops. Also, the C4 crops had higher Ca, P, K, Mg, Fe, and Zn than C3 crops. Both C3 and C4 crops were able to meet the requirements of CP, TDN, and minerals for a dry gestating beef cattle. Considering ease of establishment and forage yield, only four of the 10 C4 crops [two crown millet (Panicum miliaceum) varieties (red and white proso millets) and two sorghum Sudangrass (S. bicolor × S. Sudanese) varieties (BMR and Grazex III)] would be a fit for swath grazing or pasture.

How does leaf physiological acclimation impact forage production and quality of a warmed managed pasture of Stylosanthes capitata under different conditions of soil water availability?

Tropical pastures play a significant role in the global carbon cycle and are crucial for world livestock production. Despite its importance, there is a paucity of field studies that clarify how tropical pasture species will be affected by environmental changes predicted for tropical regions. Using a temperature-free air-controlled enhancement (T-FACE) system, we increased canopy temperature (+2 °C over ambient) and evaluated the effects of warming under two soil moisture conditions in a factorial design over the physiology, forage production, and forage quality of a tropical forage legume, Stylosanthes capitata. Under well-watered conditions, warming increased the PSII efficiency, net photosynthesis, and aboveground biomass accumulation, but reduced forage quality and digestibility by decreasing crude protein content and increasing lignin content. Non-irrigated conditions under ambient temperature reduced leaf water status presumably promoting the reduction in net photosynthesis, forage production, and forage quality and digestibility. Under the combination of canopy warming and non-irrigated conditions, warming mitigated the effects of reduced soil moisture on leaf photosynthesis and biomass production, but a significant interaction reduced forage quality and digestibility more than under isolated treatments of warming or non-irrigated conditions. We found a potential physiological acclimation of the tropical forage species to moderate warming when grown under rainfed or well-watered conditions. However, this acclimation was achieved due to a trade-off that reduced forage nutritional value and digestibility that may impact future animal feeding, livestock production, and would contribute to methane emissions.

Modification of the summative equation to estimate daily total digestible nutrients for bermudagrass pasture.

In forage-animal nutrition modeling, diet energy is estimated mainly from the forage total digestible nutrients (TDN). As digestibility trials are expensive, TDN is usually estimated using summative equations. Early summative equations assumed a fixed coefficient to compute digestible fiber using the lignin-to-neutral detergent fiber (NDF) ratio. Subsequently, a structural coefficient (φ) was added to the summative equations to reflect an association between lignin and cell wall components. Additional modifications to the summative equations assumed a constant φ value, and they have been used as a standard method by many commercial laboratories and scientists. For feeds with nutritive values that do not change much over time, a constant φ value may suffice. However, for forages with nutritive values that keep changing during the grazing season owing to changes in weather and plant maturity, a constant φ value may add a systematic bias to prediction because it is associated with the variable lignin-to-NDF ratio. In this study, we developed a model to estimate φ as a function of the day of the year by using the daily TDN values of bermudagrass [Cynodon dactylon (L.) Pers.], a popular warm-season perennial grass in the southern United States. The variable φ model was evaluated by using it in the TDN equation and comparing the estimated values with the observed ones obtained from several locations. Values of the various measures of fit used-the Willmott index (WI), the modeling efficiency (ME), R2, root mean square error (RMSE), and percent error (PE)-showed that using the variable φ vis-à-vis the constant φ improved the TDN equation significantly. The WI, ME, R2, RMSE, and PE values of 0.94, 0.80, 0.80, 2.5, and 4.7, respectively, indicated that the TDN equation with the variable φ model was able to mimic the observed values of TDN satisfactorily. Unlike the constant φ, the variable φ predicted more closely the forage nutritive value throughout the grazing season. The variable φ model may be useful to forage-beef modeling in accurately reflecting the impacts of plant maturity and weather on daily forage nutritive value and animal performance.

Influence of Annual Plant Diversity on Forage Productivity and Nutrition, Soil Chemistry, and Soil Microbial Communities

Forage cover crops are gaining in popularity on the Canadian prairies, where multi-species crop mixtures are grown for soil and ecosystem enhancing benefits, but also harvested for forage. As the use of these forage mixtures increases, more knowledge is needed to understand the impact these mixtures have on forage production systems. The objective of this study was to determine the effects of increasing plant species diversity on forage productivity, soil chemistry, and soil microbial communities. Field trials were conducted in 2016 and 2017 at two separate locations in the Canadian Prairie region that included four treatments: (1) oat monoculture, (2) 3 spp. mixture (1 grass, 1 legume, 1 brassica), (3) 6 spp. mixture (2 grasses, 2 legumes, 2 brassicas), and (4) 9 spp. mixture (3 grasses, 3 legumes, 3 brassicas). Soil and plant samples were collected at the mid and late growing season to assess soil chemistry, plant biomass and composition, forage nutrition and quality, and soil bacterial and fungal communities. Overall, the oat monoculture had the highest biomass productivity, while the 9 spp. mixture produced the lowest biomass among the treatments. All three mixtures had a better nutritional profile (i.e., greater concentrations of Ca, Cu, Fe, total Kjeldahl nitrogen (TKN), total phosphorus (TP) and total potassium (TK), and lower concentrations of acid detergent fiber (ADF) and neutral detergent fiber (NDF)) compared to the monoculture. Differences in forage nutrition were particularly heightened at the end of the growing season. Soil chemical properties did not differ greatly among the treatments with the exception of higher levels of soil nitrate availability in the mixtures compared to the monoculture. Early indicators of a shift in soil microbial diversity and fungal community composition, and an increased abundance of fungal pathotrophs in the mixtures compared to the oat monoculture, was observed at one of the field sites. This study indicates that increasing plant species diversity does not always lead to an increase in biomass production or significant changes or improvements in soil microbial communities. However, the inclusion of multiple plant species can improve the quality and nutritive value of forages over a monoculture forage crop.

Comparison of benchtop and handheld near‐infrared spectroscopy devices to determine forage nutritive value

AbstractThe quality of predicted plant‐, soil‐, and animal‐response values from near‐infrared (NIR) reflectance spectra depends on the ability to generate appropriate NIR models. The first step in the development of NIR models is collection of spectral data. Limited work, however, has been reported that compares NIR models for prediction of forage nutritive value when the spectra are obtained from devices with different spectral ranges and resolutions. The objectives of this study were to (a) develop and evaluate NIR spectroscopy models using a benchtop‐type (FOSS) and two handheld NIR devices (microPHAZIR and DLP NIRscan Nano EVM) to predict crude protein (CP), acid detergent fiber (ADF), amylase and sodium sulfite‐treated neutral detergent fiber (aNDF), and in vitro true dry matter digestibility (IVTD) of dried ground forage grass samples and (b) compare predictions among the three NIR devices. Switchgrass (Panicum virgatum L.) and bermudagrass [Cynodon dactylon (L.) Pers] hay samples were scanned with the NIR devices and analyzed with wet chemistry for development of NIR prediction models. Among devices, the r2 of validation values for aNDF models ranged from .81 to .87; all other r2 values were &gt;.86 and as high as .98 with standard error of prediction (SEP; g kg−1) ranging from 8.1 to 11.5 for CP, 19.1 to 23.8 for aNDF, 14.2 to 20.0 for ADF, and 26.8 to 49.9 for IVTD. The FOSS benchtop NIR prediction models consistently had the highest r2 and lowest SEP values; however, the predictive power for both handheld devices was similar to the benchtop‐type device.

How the structure and form of vegetation in a black locust (Robinia pseudoacacia L.) silvopastoral system influences tree growth, forage mass and its nutrient content

By using two thinning intensity regimes on a dense 16-year-old black locust (Robinia pseudoacacia L.) stand, two silvopastures were created: a medium density silvopasture (MDS) with 60% mean crown cover and a low density silvopasture (LDS) with 30% mean crown cover. An unthinned section of the stand with 90% mean crown cover was used as control (high density silvopasture: HDS). We measured the diameter at breast height (DBH) and tree height of black locust trees, in all three silvopastures, in 2011 (year of thinning), 2012 and 2013. In addition, we determined the forage production (in 2012 and 2013) and nutritive value (in 2013) of herbaceous vegetation and black locust shoots in the understory. The mean DBH for HDS, MDS and LDS increased from 7.6, 9.5 and 10.9 cm in 2011 to 8.6, 10.7 and 12.1 cm in 2013, respectively. The mean tree height also increased in the same period from 7.9, 9.1 and 9.8 m to 8.9, 10.1 and 10.6 m, for HDS, MDS and LDS, respectively. The mean herbage production was similar (P > 0.05) among silvopastures, although there was a tendency to be higher in the MDS and LDS (1866 and 1957 kg DM/ha, respectively) compared to HDS (1682 kg DM/ha). Additionally, browse from black locust shoots increased forage in MDS and LDS by 751 and 1201 kg DM/ha, respectively. Black locust browse had a higher overall nutritive value than herbage across silvopastures and months. In terms of crude protein, the content in black locust browse was on average twice as high, across sites and years, as that of herbage (239.4 vs. 104.1 g/kg DM; P < 0.05). While neutral detergent fiber and acid detergent fiber content of black locust browse were consistently lower (P < 0.05) than that of herbage, acid detergent lignin content of browse material was higher (P < 0.05) than that of herbage and averaged 94.7 and 75.4 g/kg DM, respectively. Overall, our results show that thinning resulted in higher values for both DBH and height of trees and increased forage in the understory by supplementing herbage with browse of high nutritive value.

Herbage yield and quality of &lt;i&gt;Megathyrsus&lt;/i&gt; cultivars in Northeast Thailand

A field trial in Northeast Thailand during 2015‒2018 evaluated the forage accumulation and nutritive value of 5 Megathyrsus cultivars, Mombasa, Tanzania, Massai, Zuri and Mun River. Mombasa and Tanzania are commonly grown in Thailand, but Massai, Zuri and Mun River had not been evaluated in Thailand before. Overall accumulated DM yields for the various cultivars over the 3 years were 24,550 kg/ha for Tanzania, 30,900 kg/ha for Massai, 32,700 kg/ha for Mombasa, 35,600 kg/ha for Mun River and 35,700 kg/ha for Zuri. Over 3 wet seasons, Mun River and Zuri accumulated 49% more total DM and Mombasa 35% more total DM than Tanzania. Massai accumulated lower total DM yields than Zuri and Mun River in the second and third wet seasons, similar yields to Mombasa, and higher yields than Tanzania in those 2 seasons. Crude protein concentrations in forage were higher in the dry season than in the wet season and in leaves than in stems. There were no consistent differences in CP% of the various cultivars in wet or dry seasons. ADF and NDF concentrations in the dry season were lower than those in the wet season and leaf ADF and NDF concentrations were lower than concentrations in stems. There were no consistent differences of ADF and NDF concentrations between cultivars throughout the study. This trial showed that both Zuri and Mun River would be ideal replacements for Mombasa and Tanzania in Northeast Thailand, as they would appeal to smallholder farmers for cut-and-carry forage with their upright, broad leaves, and at least similar DM production to Mombasa and superior DM production to Tanzania.

Yield, persistence, forage nutritive value, and preference of perennial ryegrass under grazing

AbstractPerennial ryegrass (PR) is a quality and high yielding forage that tends to lack winter hardiness to persist in the upper Midwest. The objective was to evaluate yield, stand persistence, forage nutritive value, and preference of experimental populations of winter hardy PR grown in monoculture and in mixture with white clover under livestock grazing. Research was conducted in St. Paul and Grand Rapids, MN. Meadow fescue (MF), tall fescue (TF), orchardgrass (OG), a reference PR, and two experimental populations of PR were grazed every 32 days by either horses (St. Paul) or cow‐calf pairs (Grand Rapids). Prior to grazing, forage yield and quality samples were collected, and post‐grazing, fields were visually assessed for the percentage of forage removal to determine preference. Yields of all PR (6.9 to 7.6 Mg ha−1) were similar, but lower compared to other cool‐season grasses (CSG). Persistence was similar among all CSG in St. Paul; however, it was lower for all PR in Grand Rapids compared to other CSG. All PR were highly preferred by both horses (≥74% removal) and cattle (≥70% removal) and were consistently among the highest for crude protein (CP; 200 g kg−1), equine digestible energy (DE; 2.35 Mcal kg−1) and bovine metabolizable energy (ME; 2.6 Mcal kg−1), moderate for nonstructural carbohydrates (NSC; 136 g kg−1), and among the lowest for neutral detergent fiber (NDF; 518 g kg−1). Experimental populations of PR produced forage of high nutritive value, but yield and stand persistence may be less compared to other CSG at some locations.

Dry Matter Intake, Body Weight, and Body Condition Scores of Blanketed and Nonblanketed Horses in the Upper Midwest

Thermoregulation is an energy-expensive process, which can be mitigated by blanketing horses in cold climates, potentially preventing weight loss or leading to decreased feed intake. The objective of this study was to evaluate feed intake, body weight (BW), and body condition scores (BCSs) in blanketed and nonblanketed horses. In October 2019, 16 mature adult horses were blocked by breed and BCS and randomly assigned to a blanketed (n = 8) or nonblanketed (n = 8) treatment; blankets were placed. Data were collected in December 2019 and January 2020 in River Falls, Wisconsin. During the study, horses were housed in dry lots and fed grass-legume mixed round bales. At the start of each trial period, BW and BCSs of horses were taken, hay cores were taken for nutritive analysis, and hay bales were weighed. Hay waste was collected daily, and when hay could no longer be consumed ad libitum, the remaining hay was removed from both pens (orts) and new bales were fed. Hay waste and orts were dried and daily dry matter intake was estimated as the difference between hay provided minus hay waste and orts during the trial period divided by the total BW of the pen. The average bale weight, forage nutritive value, BW, and BCS did not differ across treatment groups (P ≥ .05). However, the daily dry matter intake differed (P ≤ .05) at 2.31% BW for blanketed horses and 2.51% BW for nonblanketed horses. These results suggest blanketed horses conserve energy leading to decreased feed intake.