scholarly journals Evaluating Digestibility and Toxicity of Native Warm-season Grasses for Equines

2020 ◽  
Author(s):  
S M Ghajar ◽  
H McKenzie ◽  
J Fike ◽  
B McIntosh ◽  
B F Tracy
Keyword(s):  
Dry Matter ◽  
Latin Square ◽  
Warm Season ◽  
Big Bluestem ◽  
Cool Season ◽  
Digestible Energy ◽  
Eastern Gamagrass ◽  
Dry Matter Digestibility ◽  
Structural Carbohydrate ◽  
Warm Season Grasses

Abstract Introduced cool-season grasses are dominant in Virginia’s grasslands, but their high digestible energy and non-structural carbohydrate (NSC) levels pose a risk for horses prone to obesity and laminitis. Native warm-season grasses (NWSG) have lower digestible energy and NSC levels that may be more suitable for horses susceptible to laminitis. Although NWSGs have desirable characteristics, they are novel forages for horses. Little is known about NWSG intake or potential toxicity to horses or how grazing by horses may affect NWSG swards. The overall objectives of this research were to 1) assess voluntary intake, toxicological response, and apparent digestibility of NWSG hays fed to horses; and 2) evaluate the characteristics of three NWSG species under equine grazing. For the first objective, a hay feeding trial using indiangrass (IG) (Sorghastrum nutans) and big bluestem (BB) (Andropogon gerardii) was conducted with 9 Thoroughbred geldings in a replicated 3 x 3 Latin square design. Voluntary dry matter intake of IG and BB hays by horses were 1.3% and 1.1% of BW/d, lower than orchardgrass (Dactylis glomerata), an introduced cool-season grass, at 1.7% of BW/d (P = 0.0020). Biomarkers for hepatotoxicity remained within acceptable ranges for all treatments. Apparent dry matter digestibility (DMD) did not differ among hays, ranging from 39 to 43%. Non-structural carbohydrate levels ranged from 4.4 to 5.4%, below maximum recommended concentrations for horses susceptible to laminitis. For the second objective, a grazing trial was conducted comparing IG, BB, and eastern gamagrass (Tripsacum dactyloides) (EG) yields, forage losses, changes in vegetative composition, and effects on equine bodyweight. Nine, 0.1-hectare plots were seeded with one of the three native grass treatments, and each plot was grazed by one Thoroughbred gelding in two grazing bouts, one in July and another in September 2019. Indiangrass had the greatest available forage, at 4340 kg/ha, compared with 3590 kg/ha from BB (P < 0.0001). Eastern gamagrass plots established poorly, and had only 650 kg/ha available forage during the experiment. Grazing reduced standing cover of native grasses in IG and BB treatments by about 30%. Horses lost 0.5 to 1.5 kg BW/d on all treatments. Findings suggest indiangrass and big bluestem merit further consideration as forages for horses susceptible to obesity and pasture-associated laminitis.

Herbicides for Postemergence Control of Annual Grass Weeds in Seedling Forage Grasses

Weed Science ◽  
1989 ◽  
Vol 37 (3) ◽  
pp. 375-379 ◽  
Author(s):  
Thomas J. Peters ◽  
Russell S. Moomaw ◽  
Alex R. Martin
Keyword(s):  
Warm Season ◽  
Big Bluestem ◽  
Forage Grasses ◽  
Annual Grass ◽  
Cool Season ◽  
Intermediate Wheatgrass ◽  
Green Foxtail ◽  
Annual Grasses ◽  
Large Crabgrass ◽  
Warm Season Grasses

The control of three summer annual grass weeds with herbicides during establishment of forage grasses was studied near Concord and Mead, NE, in 1984, 1985, and 1986. Three cool-season forage grasses, intermediate wheatgrass, tall fescue, and smooth bromegrass, and two warm-season grasses, big bluestem and switchgrass, were included. The control of three major summer annual grasses, green foxtail, barnyardgrass, and large crabgrass, was excellent with fenoxaprop at 0.22 kg ai/ha. Slight to moderate injury to cool-season forage grasses and severe injury to warm-season grasses were evident. Sethoxydim at 0.22 kg ai/ha and haloxyfop at 0.11 kg ai/ha controlled green foxtail and large crabgrass, but not barnyardgrass. Sulfometuron-treated big bluestem and switchgrass plots had the best forage stand frequencies and yields and, at the rate used, sulfometuron satisfactorily controlled green foxtail but only marginally controlled barnyardgrass and large crabgrass.

Effect of Aminocyclopyrachlor on Seedling Grasses

2016 ◽  
Vol 9 (2) ◽  
pp. 87-95 ◽  
Author(s):  
Katie L. Wirt ◽  
Rodney G. Lym
Keyword(s):  
Native Species ◽  
Warm Season ◽  
Separate Experiment ◽  
Grass Species ◽  
Big Bluestem ◽  
Forage Production ◽  
Cool Season ◽  
Intermediate Wheatgrass ◽  
Western Wheatgrass ◽  
Warm Season Grasses

When invasive weeds are removed with herbicides, revegetation of native species is often desirable. The extended soil activity of aminocyclopyrachlor is important for long-term weed control but could reduce recovery of native species as well. The effect of aminocyclopyrachlor applied alone or with chlorsulfuron on cool- and warm-season grass species commonly used for revegetation was evaluated. The cool-season grasses included green needlegrass, intermediate wheatgrass, and western wheatgrass, whereas the warm-season grasses were big bluestem, sideoats grama, and switchgrass. A separate experiment was conducted for each species. Aminocyclopyrachlor was applied at 91 to 329 g ha−1 alone or with chlorsulfuron from 42 to 133 g ha−1 approximately 30 d after emergence. Warm-season grasses generally were more tolerant of aminocyclopyrachlor than the cool-season grasses evaluated in this study. Switchgrass and big bluestem were the most tolerant of the warm-season species when aminocyclopyrachlor was applied at 168 g ha−1 and averaged 199 and 150% forage production, respectively, compared with the control. Green needlegrass was the most tolerant cool-season grass. Western wheatgrass was the least tolerant species evaluated because forage production only averaged 32% of the control the year after treatment and thus would not be suitable for seeding if aminocyclopyrachlor was applied. The effect of chlorsulfuron applied with aminocyclopyrachlor varied by grass species. For example, green needlegrass injury 8 wk after treatment (WAT) averaged 30 and 48% when aminocylopyrachlor was applied alone, respectively, but injury was reduced to less than 16% when aminocyclopyrachlor was applied with chlorsulfuron. However, injury on the less-tolerant intermediate wheatgrass ranged from 48 to 92% by 4 WAT when aminocyclopyrachlor was applied alone and from 60 to 86% when chlorsulfuron was included in the treatment.

Seasonal and temperature effects on mycorrhizal activity and dependence of cool- and warm-season tallgrass prairie grasses

1992 ◽  
Vol 70 (8) ◽  
pp. 1596-1602 ◽  
Author(s):  
S. P. Bentivenga ◽  
B. A. D. Hetrick
Keyword(s):  
Tallgrass Prairie ◽  
Mycorrhizal Fungi ◽  
Warm Season ◽  
Growing Season ◽  
Cool Temperature ◽  
Cool Season ◽  
Fungal Activity ◽  
Prairie Grasses ◽  
Vesicular Arbuscular ◽  
Warm Season Grasses

Previous research on North American tallgrass prairie grasses has shown that warm-season grasses rely heavily on vesicular–arbuscular mycorrhizal symbiosis, while cool-season grasses are less dependent on the symbiosis (i.e., receive less benefit). This led to the hypothesis that cool-season grasses are less dependent on the symbiosis, because the growth of these plants occurs when mycorrhizal fungi are inactive. Field studies were performed to assess the effect of phenology of cool- and warm-season grasses on mycorrhizal fungal activity and fungal species composition. Mycorrhizal fungal activity in field samples was assessed using the vital stain nitro blue tetrazolium in addition to traditional staining techniques. Mycorrhizal activity was greater in cool-season grasses than in warm-season grasses early (April and May) and late (December) in the growing season, while mycorrhizal activity in roots of the warm-season grasses was greater (compared with cool-season grasses) in midseason (July and August). Active mycorrhizal colonization was relatively high in both groups of grasses late in the growing season, suggesting that mycorrhizal fungi may proliferate internally or may be parasitic at this time. Total Glomales sporulation was generally greater in the rhizosphere of cool-season grasses in June and in the rhizosphere of the warm-season grasses in October. A growth chamber experiment was conducted to examine the effect of temperature on mycorrhizal dependence of cool- and warm-season grasses. For both groups of grasses, mycorrhizal dependence was greatest at the temperature that favored growth of the host. The results suggest that mycorrhizal fungi are active in roots when cool-season grasses are growing and that cool-season grasses may receive benefit from the symbiosis under relatively cool temperature regimes. Key words: cool-season grasses, tallgrass prairie, vesicular–arbuscular mycorrhizae, warm-season grasses.

EFFECT OF STRUCTURAL AND CHEMICAL FACTORS OF FORAGES ON POTENTIALLY DIGESTIBLE FIBER, INTAKE, AND TRUE DIGESTIBILITY BY RUMINANTS

1988 ◽  
Vol 68 (3) ◽  
pp. 787-799 ◽  
Author(s):  
V. GIRARD ◽  
G. DUPUIS
Keyword(s):  
Cell Wall ◽  
Dry Matter ◽  
Plant Cell Wall ◽  
Neutral Detergent Fiber ◽  
Optimum Number ◽  
Apparent Digestibility ◽  
Cool Season ◽  
Dry Matter Digestibility ◽  
True Digestibility

In view of the large variation found in plant cell wall digestibilities with ruminants, an attempt was made to group 124 feeds into different lignification classes (clusters) on the basis of chemical characteristics. Each feed cluster was described using a structural coefficient [Formula: see text] that related the potentially digestible fiber (PDF, %) to the ratio between lignin and cell wall volume. The optimum number of clusters was determined iteratively by performing a regression of the apparent digestibility of dry matter at maintenance level (DDM1, %) against the PDF and cell soluble (SOL, %) contents of feeds. The [Formula: see text] coefficients varied from 0.05 (grains, N = 13) to 1.85 (corn silage, N = 3) and increased with the maturity of the grasses from 0.88 (legumes, vegetative cool season grasses, N = 26) to 1.33 (mature, cool season grasses, N = 19). Predicted PDF were closely correlated (r > 0.9, P < 0.01) to in vitro cell wall disappearances (IVCWD). Apparently digestible cell wall in four grasses and four legumes increased linearly with 96-h IVCWD and standard error (SE) was similar to the SE of predicted apparent digestible SOL from SOL concentrations. Assuming that similarity between SE could be also observed in larger samples, PDF and SOL were used in summative equations to predict apparent dry matter digestibility. DDM1 discounted for intake (DDM1 – 4, %) was regressed against SOL and PDF concentrations of 87 feeds:[Formula: see text]with ds and df, the true digestibilities of SOL and PDF. Estimates of ds and df were 0.98 and 0.95 for a zero-production (maintenance) level of intake, and 0.91 and 0.79 for an intake level four times maintenance. Since the true digestibility of the PDF component was only 4% – 13% lower than that of the cell soluble component, the concentration of PDF in cell wall was the major determinant in the variation in apparent digestibility of forages. Key words: lignin, neutral detergent fiber, true digestibility, cluster analysis, feeds

The effect of different proportions of hay and fortified rolled barley in the diet on digestible-energy value and urinary-energy excretion by cattle

1972 ◽  
Vol 79 (1) ◽  
pp. 99-103 ◽  
Author(s):  
A. M. Raven
Keyword(s):  
Organic Matter ◽  
Dry Matter ◽  
Rumen Fluid ◽  
Latin Square ◽  
Progressive Increase ◽  
Linear Increase ◽  
Metabolizable Energy ◽  
Digestible Energy ◽  
Gross Energy ◽  
Concentrate Treatment

SUMMARYA 6 x 6 Latin Square balance experiment was carried out using six Friesian steers, each of which initially weighed about 304 kg. The six treatments studied were an all-hay diet and five other diets containing 20,40,60,80 and 100 % of rolled barley fortified with mineral and vitamin supplements, accompanied by correspondingly reduced proportions of hay. Each diet was fed at an estimated maintenance level of feeding.The progressive increase in the proportion of concentrate gave a significantly linear increase (P < 0·001) in both digestible and calculated metabolizable energy. The actual increase in digestible energy was from 2·62Mcal/kg dry matter (59·3% of the gross energy) on the all-hay treatment to 3·42 Mcal/kg dry matter (79·5% of the gross energy) on the all-concentrate treatment. Use of the determined digestible energy values for the all-hay and fortified barley diets to calculate the digestible energy of the four mixed diets gave results in reasonably good agreement with the determined values, the maximum difference being 0·12 Mcal/kg dry matter, which represented 3·83 % of the determined value. The losses of energy in the urine expressed as percentages of the gross energy of the diets showed a small but significantly linear decrease (P < 0·01) with increase in proportion of barley in the diet. The molar proportions of steamvolatile acids in samples of rumen fluid taken from two animals on each treatment indicated that increase in the proportion of concentrate was associated with tendencies for increase in acetic acid, decrease in propionic acid and little change in butyric acid. The mean digestibility of the organic matter was 62·6 % on the all-hay treatment and 81·8 % on the all concentrate treatment. The progressive increase in the proportion of concentrate gave a significantly linear increase (P < 0·001) in digestibility of the organic matter. Although intakes of nitrogen decreased with increase in the proportion of concentrate due to a decrease in the amount of dry matter fed, the weights of nitrogen retained were well maintained and when expressed as percentages of intake showed a significantly linear increase (P < 0·01).

RESPONSE OF THREE WARM-SEASON GRASSES TO VARYING FERTILITY LEVELS ON FIVE SOILS

1982 ◽  
Vol 62 (3) ◽  
pp. 657-665 ◽  
Author(s):  
R. W. TAYLOR ◽  
D. W. ALLINSON
Keyword(s):  
New England ◽  
Panicum Virgatum ◽  
Warm Season ◽  
Late Summer ◽  
Control Treatment ◽  
Yield Response ◽  
Limiting Factor ◽  
Big Bluestem ◽  
P Fertilization ◽  
Warm Season Grasses

Animal production in New England has been limited by inadequate forage during mid- to late summer when cool-season grasses are in summer dormancy. Big bluestem (Andropogon gerardi Vitman), indiangrass [Sorghastrum nutans (L.) Nash] and switchgrass (Panicum virgatum L.) are warm-season grasses that may be a perennial source of summer forage. Since production of these warm-season grasses would be limited to the less fertile soils of the region, a greenhouse study was conducted to examine the growth and quality of these species in five acid, infertile soils as well as fertilizer-amended soils. The soils were fertilized with limestone (L), limestone plus nitrogen (LN), limestone, nitrogen plus phosphorus (LNP), and limestone, nitrogen, phosphorus plus potassium (LNPK). Limestone was applied to adjust soils to a pH of 6.5. Fertilizer was applied at rates of 45, 117 and 111 kg/ha of N, P and K, respectively. First harvest yields were greatest for switchgrass and big bluestem, but indiangrass produced significantly greater yields than either of the other grasses in the second harvest. In both harvests, the yields of all grasses were greatest under the LNP and LNPK fertility regimes. Nitrogen, without P, did not significantly increase yields above the control treatment in the first harvest. Yield responses to P fertilization varied with soils. Although P appeared to be the limiting factor insofar as growth was concerned, the yield response from P fertilization would probably be limited without N fertilization. Indiangrass was significantly higher in crude protein and K concentration and significantly lower in Ca concentration than big bluestem and switchgrass. Phosphorus concentrations were below the recommended levels for ruminant nutrition.

The effect of dietary concentrations of digestible energy on the performance and carcass characteristics of early-weaned pigs

1975 ◽  
Vol 21 (3) ◽  
pp. 285-294 ◽  
Author(s):  
R. G. Campbell ◽  
M. R. Taverner ◽  
P. D. Mullaney
Keyword(s):  
Growth Rate ◽  
Growth Performance ◽  
Shoulder Joint ◽  
Dry Matter ◽  
Carcass Characteristics ◽  
Live Weight ◽  
Maximum Growth ◽  
Average Weight ◽  
Digestible Energy ◽  
Dry Matter Digestibility

SUMMARYFifty-four pigs weaned at 3 weeks of age were allocated at an average weight of 5·4 kg to two experiments to examine the effects of diets having digestible energy (DE) concentrations ranging from 2910 to 3940 kcal/kg.In the first experiment pig growth performance and the dry-matter digestibility of the experimental diets were measured between 3 and 8 weeks of age. The composition of the carcass at 8 weeks of age was correlated with the composition of various carcass joints.In the second experiment pig growth performance was measured over the live-weight range 5-4 to 20 kg.The findings were:1. Growth rate was linearly related to DE intake.2. The optimum DE level for maximum growth was 3640 kcal/kg.3. The efficiency of utilization of DE for growth did not vary in the first experiment but was poorest at a DE concentration of 3245 kcal/kg in the second.4. The DE content of the diet had no significant effect on carcass characteristics at 8 weeks of age in the first experiment or at 20 kg live weight in the second.5. The proportion of fat and lean in the 8-week carcass was significantly (P < 0·01) correlated with that of the shoulder joint.

Digestible energy of wheat and oat grains when fed to sheep

1971 ◽  
Vol 11 (53) ◽  
pp. 610 ◽  
Author(s):  
MC Nottle
Keyword(s):  
Organic Matter ◽  
Dry Matter ◽  
Energy Content ◽  
The Body ◽  
Wheat Grain ◽  
Crude Fibre ◽  
Digestible Energy ◽  
Dry Matter Digestibility ◽  
Gross Energy ◽  
Feeding Trials

In pen feeding trials with eight Merino wethers, digestion coefficients were estimated for rations of cereal chaff-wheat grain-oat grain mixture, and wheat grain and oat grain fed separately at two levels of intake. Digestion coefficients for wheat and oat grain fed at 675 g/day in a double crossover experiment were dry matter 89.4, 80.8 per cent, organic matter 90.1, 82.6 per cent, protein 82.3, 77.6 per cent, ether extract 84.1, 90.9 per cent, crude fibre 33.2, 59.9 per cent, nitrogen free extractives 93.2, 85.8 per cent, energy 88.1, 81.0 per cent, total digestible nutrients 91.6, 87.1 per cent, and starch equivalents 90.7, 85.7. When these grains were fed at 785 g/day there was about 10 per cent improvement in crude fibre digestibility for both grains and 1-2 per cent improvement for other estimations with oats but not with wheat. The gross energy content of the wheat and oat grains when fed at 675 g/day was 4407 and 4700 calories/g dry matter. The digestible energy of the wheat in calories/g dry matter and organic matter was 3869 � 30, 3933 � 30 and for oats 3791 � 59, 3910 � 61. When fed at 785 g/day these values for wheat were 3850 � 50,3911 � 51 and for oats 3796 � 34, 3913 � 51. A highly significant relationship was found between energy and dry matter digestibility which for wheat diets was Y = 1.074x 7.840. r = 0.993 (P<0.001), and for oats and the mixed diet of cereal chaff-oat grain-wheat grain, Y = 0.983x + 1.550. r = 0.996 (P<0.001) where Y = energy and X = dry matter digestibility and r = the coefficient of correlation. Because of the similar digestible energy content of, and the body weight gains of sheep on, these two grains it was concluded that under the present conditions these grains were equivalent weight for weight.

scholarly journals Digestibility and Retention Time of Coastal Bermudagrass (Cynodon dactylon) Hay by Horses

Animals ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 1148
Author(s):  
Tayler L. Hansen ◽  
Elisabeth L. Chizek ◽  
Olivia K. Zugay ◽  
Jessica M. Miller ◽  
Jill M. Bobel ◽  
...  
Keyword(s):  
Retention Time ◽  
Cynodon Dactylon ◽  
Ethylenediaminetetraacetic Acid ◽  
Latin Square ◽  
Warm Season ◽  
Neutral Detergent Fiber ◽  
Dry Matter Digestibility ◽  
Coastal Bermudagrass ◽  
Digesta Passage ◽  
Kinetics Of

Bermudagrass (Cynodon dactylon) and other warm-season grasses are known for their increased fiber concentrations and reduced digestibility relative to cool-season grasses and legumes. This study investigated the digestive characteristics and passage kinetics of three maturities of Coastal bermudagrass hay. A 5 × 5 Latin square design experiment was used to compare the digestion of five hays: alfalfa (Medicago sativa, ALF), orchardgrass (Dactylis glomerata, ORCH), and Coastal bermudagrass harvested at 4 (CB 4), 6 (CB 6), and 8 weeks of regrowth (CB 8). Horses were fed cobalt-ethylenediaminetetraacetic acid (Co-EDTA) and ytterbium (Yb) labeled neutral detergent fiber (NDF) before an 84-h total fecal collection to determine digesta retention time. Dry matter digestibility was greatest for ALF (62.1%) and least for CB 6 (36.0%) and CB 8 diets (36.8%, SEM = 2.1; p < 0.05). Mean retention time was longer (p < 0.05) for Coastal bermudagrass (particulate 31.3 h, liquid 25.3 h) compared with ORCH and ALF (28.0 h, SEM = 0.88 h; 20.7 h, SEM = 0.70 h). Further evaluation of digesta passage kinetics through mathematical modeling indicated ALF had distinct parameters compared to the other diets. Differences in digestive variables between forage types are likely a consequence of fiber physiochemical properties, warranting further investigation on forage fiber and digestive health.

A note on the relationship between the digestible dry matter and the digestible energy content of ruminant diets

1961 ◽  
Vol 1 (1) ◽  
pp. 24 ◽  
Author(s):  
RJ Moir
Keyword(s):  
Dry Matter ◽  
Energy Content ◽  
Accurate Description ◽  
Digestible Energy ◽  
Dry Matter Digestibility ◽  
Wide Range ◽  
Ruminant Diets ◽  
The Relationship

The digestible energy content (y, in Calories per gram) of a wide range of foodstuffs for ruminants may be accurately estimated from the dry matter digestibility (x per cent) by the regression y = 0.0467 x - 0.158 (r = 0.998). It follows that dry matter digestibility itself is a simple and accurate description of the digestible energv content of foodstuffs for ruminants.

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