Screening Perennial Forages By Mob-Grazing Technique,
2026
University of Florida
Screening Perennial Forages By Mob-Grazing Technique, P Mislevy, G O. Mott, F G. Martin
IGC Proceedings (1977-2023)
Mob-grazing allows the study of forage response to severe defoliation by grazing animals on a limited land area. This technique was used to evaluate two Digi,taria spp., one Paspalum sp., and 13 Cynodon spp. at grazing frequencies of 2, 3, 4, 5, and 7 weeks. Average dry-matter (DM) yield generally increased as grazing frequency decreased from 2 to 7 weeks. Decreasing the grazing frequency from 4 to 7 weeks resulted in a DM yield increase of 50% to 75% for most entries. Grazing at 4-and 5-week intervals resulted in the highest (42%) and lowest (22%) weed contamination, respectively, when compared …
Grazing Techniques For Evaluating Quality Of Forage Cultivars In Small Pastures,
2026
USDA-SEA-AR
Grazing Techniques For Evaluating Quality Of Forage Cultivars In Small Pastures, A G. Matches, F A. Martz, D A. Sleeper, R L. Belyea
IGC Proceedings (1977-2023)
Because plant beeders have few laboratory analyses of forage quality that are good predictors of animal performance when grazing pasture, • we studied the feasibility of grazing small pastures with cattle in order to detect possible forage-quality differences among cultivars of tall fescue (Festuca anmdinacea Schreb). Kentucky 31, Kenmont, Fawn, and Missouri 96 tall fescue cultivars and Kenhy, a Lolium-Festuca derivative, were grown in 0.47-ha pastures and grazed in separate periods ranging from 35 to 68 days during the spring, summer, and autumn of 1974-1976. Between grazing periods, cattle grazed a reserve pasture of the same cultivar. All test pastures …
Structural Characteristics Limiting Digestion Of Forage Fiber,
2026
USDA-SEA-AR
Structural Characteristics Limiting Digestion Of Forage Fiber, D E. Akin
IGC Proceedings (1977-2023)
Cell walls of forage were studied for structural and chemical factors that limit digestion by rumen microorganisms. Techniques used to investigate digestion were histochemistry, electron microscopy, and anaerobic culturing of rumen populations on specific substrates. Certain tissues, such as the xylem cells, totally resisted degradation by rumen microorganisms; these tissues stained positive for lignin with acid phloroglucinol (Weisner test). Other supportive tissues, such as the sclerenchyma in blades, stained positive for lignin with chlorine-sulfite (and also the Maule test) and were also generally resistant to microbial digestion. Microscopic studies revealed that certain living tissues (i.e., those having cytoplasm and organelles …
Relationship Of Forage-Evaluation Techniques To The Intake And Digestibility Of Tropical Grasses,
2026
USDA-SEA-AR
Relationship Of Forage-Evaluation Techniques To The Intake And Digestibility Of Tropical Grasses, S M. Abrams, H Hartadi, C M. Chaves, J E. Moore, W R. Ocumpaugh
IGC Proceedings (1977-2023)
Seventy-six grass hays, harvested at 2, 4, 6, and 8 weeks of regrowth, were fed ad libitum to wethers in a digestibility and intake trial. Range of organic-matter digestibility (OMD) was 54.l % to 72.3% and that of organic-matter intake (OMI) 17.3 to 27.4 g/kg. Lignin was the chemical component most highly related to OMD (r = - 0.72). Neutral detergent fiber (NDF) was better than acid detergent fiber (ADF) as a predictor of OMD (r = - 0.66 vs. - 0.45). In-vitro NDF digestibility (IVNDFD) was superior to in-vitro organic-matter digestibility (IVOMD) and all other analyses as a predictor …
Using A Dynamic Model Of Fiber Digestion And Passage To Evaluate Forage Quality,
2026
University of Georgia
Using A Dynamic Model Of Fiber Digestion And Passage To Evaluate Forage Quality, D R. Mertens, L O. Ely
IGC Proceedings (1977-2023)
Assessing forage quality depends not only upon the characteristics of the plant and animal, but also upon the dynamic interaction of the forage, rumen microorganisms, and animal. Although static variables, such as composition or 48-hour in-vitro fermentation, are important for characterizing feeds and predicting in-vivo responses under standard conditions, they provide little information that can be used to assess forage quality in dynamic situations. Dynamic properties, such as rates of digestion and passage, can be used to predict digestion under varied circumstances but require an appropriate mathematical model. Our objectives were to describe a dynamic model of fiber digestion and …
Bulk Volume: A Parameter For Measuring Forage Quality And Its Influence On Voluntary Intake,
2026
Agricultural University
Bulk Volume: A Parameter For Measuring Forage Quality And Its Influence On Voluntary Intake, P J. Van Der Aar, H Boer, G Hof
IGC Proceedings (1977-2023)
The experiment evaluated bulk volume (ml/g meal) as a method of estimating forage quality. Samples of Lolium perenne (Lp) and Festuca arundinaea, and hay samples of Lp were collected at different stages of growth. Voluntary intakes of these forages by dairy cattle had been measured previously. Volumes of samples and volumes of cell-wall residues after 0, 6, 12, 24, and 48 hours in vitro digestion were determined.
Rate And Extent Of Fermentation And Potentially Digestible Fractions Of Various Roughages,
2026
Chung-Ang University
Rate And Extent Of Fermentation And Potentially Digestible Fractions Of Various Roughages, W J. Maeng, H S. Yun, I S. Yun
IGC Proceedings (1977-2023)
To determine in-vitro digestion characteristics - such as fermentation and amounts of potential digestibility of dry matter (PDDM), cell-wall constituents (PDCWC), acid detergent fiber (PDADF), and cellulose (PDC) - rice straw, barley straw, corn cobs, corn stover, orchardgrass, and alfafa were digested in vitro for 6, 12, 24, 36, 48, 72, and 144 hours.
Methodology For Determining Pasture And Animal Response Differences In Unbalanced Experiments With Intercorrelations Among Treatments,
2026
USDA-SEA-AR
Methodology For Determining Pasture And Animal Response Differences In Unbalanced Experiments With Intercorrelations Among Treatments, J C. Burns, R W. Harvey, F G. Giesbrecht
IGC Proceedings (1977-2023)
Conventional statistical analyses require balanced data sets. Unbalanced data can be analyzed using regression procedures, but excessive adjustments may be needed for some treatment means. The objective of this paper is to evaluate an analysis of grazing-trial data using generalized least squares. The data was obtained from a 6-year study involving 12 treatments with not all treatments being made in all years. The analyses involved estimating variance components due to years, fields, and random error and then using these estimates to obtain adjusted treatment means. Variance-component estimates for the complete data set were similar to estimates from two balanced subsets …
Use Of Principal-Component Analysis In Summarizing Nutritive And Analytical Characteristics Of Forages,
2026
University of Arkansas, Fayetteville
Use Of Principal-Component Analysis In Summarizing Nutritive And Analytical Characteristics Of Forages, O T. Stallcup, C J. Brown, Z B. Johnson, D L. Kreider, J O. York
IGC Proceedings (1977-2023)
Principal component analysis and other multivariate analyses have not been used extensively to analyze forage data. Our objective was the synthesis and summary of 98 digestion trials on forages using a principal-component analysis. The ten variables studied in all trials were dry matter (DM), crude protein (CP), digestible protein (DP), crude fiber (CF), ether extract (EE), nitrogen-free extract (NFE), ash (A), gross energy (GE), total digestible nutrients (TDN), and digestible energy (DE). Acid detergent fiber (ADF), acid detergent lignin (ADL), and cellulose (C) were summarized, in addition, for some forages. When data on thirteen variables in 24 hays were summarized, …
Yield And Forage Quality Of Panicum Virgatum,
2026
USDA-SEA-AR
Yield And Forage Quality Of Panicum Virgatum, J L. Griffin, G A. Jung
IGC Proceedings (1977-2023)
In the temperate areas of the U.S.A., high temperatures and low soil moisture in summer limit the production of cool-season grasses and, consequently, the size of most beef cow-calf herds. Warm-season grasses, most productive in midsummer, may serve as a supplement to cool-season grasses for grazing and hay. Switchgrass (Panicum virgatum L. ), a warm-season species native to the Great Plains of the U.S.A., was grown on soils low in available phosphorus at two locations in Pennsylvania to determine changes in forage dry-matter yields, leaf (leaf blade): stem (sheath+ stem) ratios, and quality of leaf and stem fractions associated …
Effect Of Experimental Methods On Results Of Voluntary Intake Experiments With Grass Cultivars,
2026
Justus-Liebig-Universitat,, Glessen
Effect Of Experimental Methods On Results Of Voluntary Intake Experiments With Grass Cultivars, U Simon, P Daniel
IGC Proceedings (1977-2023)
The amount of forage eaten by farm animals when forage is offered ad libitum is a major factor in the nutritive value of forage grasses. It is influenced by a number of internal and external factors. Experimental results of studies on the subject :reported in the literature are often contradictory, partially because, perhaps, of the methods of evaluation employed. We studied whether and to what extent different experimental procedures influenced the results of intake experiments in grass cultivars. Four cultivars of Lolium perenne differing in ploidy level and precocity were fed to sheep ad libitum, and voluntary intake was assessed …
Review Of Mechanisms Of Toxicity Of 3-Nitropropanoic Acid In Nonruminant Animals,
2026
USDA-SEA-AR
Review Of Mechanisms Of Toxicity Of 3-Nitropropanoic Acid In Nonruminant Animals, D L. Bustine, B G. Moyer
IGC Proceedings (1977-2023)
Crownvetch (Coronilla varia L.) now has limited use in the U.S.A. as a forage crop for ruminant animals. Even though crown vetch forage can contain high amounts of nutrients, intake by ruminants may be reduced. Toxicity problems upon feeding crownvetch to nonmminants have been traced to 3-nitropropanoic acid (NPA), which occurs esterified to glucose in the plant. Understanding mechanisms of toxicity in nonruminants will be helpful in avoiding livstock losses and in treating poisoned animals. Symptoms of NPA toxicity are similar in rats, mice, meadow voles, chickens, and rabbits and probably reflect central nervous system disorders and oxygen deprivation. …
Hydrocyanic Acid Potential In Stargrass (Cynodon Spp.),
2026
University of Florida
Hydrocyanic Acid Potential In Stargrass (Cynodon Spp.), P Mislevy, E M. Hodges, F G. Martin
IGC Proceedings (1977-2023)
The acreage of stargrass and bermudagrass (Cynodon spp.) throughout tropical and subtropical regions has increased greatly. However, many Cynodons have a hydrocyanic acid potential (HCN-p) that may be toxic to livestock. The purpose of this study was to determine the HCN-p in fresh and hay samples of meristematic stem tips from nine Cynodon entries at different physiological stages of growth during the summer (19°-33°C) and autumn (11° -32°C). Two selected entries (Ona and UF-5 stargrass) were also separated into meristematic stem tips, leaves and sheaths, and nodes and internodes at different stages of maturity to monitor HCN-p, dry matter (DM), …
Effect Of Level Of Nitrogen Fertilization Of Kentucky 31 Tall Fescue (Festuca Arundinacea Schreb.) On Brood-Cow Health,
2026
USDA-SEA-AR
Effect Of Level Of Nitrogen Fertilization Of Kentucky 31 Tall Fescue (Festuca Arundinacea Schreb.) On Brood-Cow Health, J A. Stuedemann, S R. Wilinson, H Ciordia, A B. Caudle
IGC Proceedings (1977-2023)
Studies were conducted to assess the long-term effects of nitrogen (N) fertilization of tall fescue on cow-calf performance and health problems, including grass tetany, fat necrosis, gastrointestinal parasitism, and nitrate poisoning. Kentucky 31 tall fescue pastures fertilized at three levels of N were grazed with Angus cows at 0.4 ha/cow on a year-round basis. Fertilization levels included high N (667 and 0 kg N/ha/yr from broiler litter in 1968-1974 and 1975-1977, respectively); moderate N (134 and 224 kg N/ha/yr from ammonium nitrate [NH4N03] in 1969 and 1970-1977, respectively); and low N (84 and 74 kg N/ha/yr from NH4N03 in 1972 …
Beef Production From Tall Fescue Treated With Mefluidide A Chemical Plant-Growth Regulator,
2026
University of Kentucky
Beef Production From Tall Fescue Treated With Mefluidide A Chemical Plant-Growth Regulator, T W. Robb, D G. Ely, C E. Rieck, S Glenn, L Kitchen, B P. Glenn, R J. Thomas
IGC Proceedings (1977-2023)
Mefluidide treatment of Kentucky 31 tall fescue (Festuca arundinacea Schreb.) in the spring will inhibit seed-head formation, maintain the forage in an immature and vegetative stage, and increase forage N and soluble-sugar content and in-vivo nutrient utilization in the ovine. Productivity of animals grazing mefluidide-treated tall fescue, however, has not been determined. The objective of this study was to evaluate agronomic characteristics of forage and productivity of yearling beef steers and heifers grazing mefluidide-treated (T) and nontreated control (C) pastures of Kentucky 31 tall fescue. Experimental pastures of Kentucky 31 tall fescue ( 4 replications at location I and one …
Role Of Alkaloids And Toxic Compounds In The Utilization Of Tall Fescue By Ruminants,
2026
University of Kentucky
Role Of Alkaloids And Toxic Compounds In The Utilization Of Tall Fescue By Ruminants, J A. Boling, R W. Hemken, L P. Bush, R C. Buckner, J A. Jackson Jr, S G. Yates
IGC Proceedings (1977-2023)
Tall fescue (Festuca arundinacea Schreb.) contains several alkaloids. Studies in our laboratory showed that perloline is a principal alkaloid in tall fescue during the summer and that concentration peaks at a time when cattle grazing tall fescue pastures frequently have severely reduced performance (summer syndrome or summer fescue toxicosis). The objectives of the following studies were (1) to determine the influence of perloline on in-vitro fermentation and in-vivo ruminant metabolism and (2) to determine the effects of two tall fescue strains selected for perloline concentration on performance of growing cattle and lactating dairy cows and on interrelationships with environmental …
Initial Rate Of Digestion And Legume Pasture Bloat,
2026
University of Calgary
Initial Rate Of Digestion And Legume Pasture Bloat, R E. Howarth, K J. Cheng, J P. Fay, W Majak, G L. Lees, B P. Goplen, J W. Costerton
IGC Proceedings (1977-2023)
Studies were conducted to provide the basic knowledge for breeding a bloat-safe alfalfa cultivar. Two working hypotheses of pasture bloat were tested. The cell-rupture theory proposed that leaf mesophyll cell rupture is an important event in the occurrence of pasture bloat. The initial-rate-of-digestion (IRD) theory proposed that susceptibility to rapid initial digestion by ruminal bacteria is a characteristic of bloat-causing forages. The studies involved comparisons of bloat-causing and bloat-safe legumes: alfalfa (Medicago sativa L. ), red clover (Trifolium pratense L.), arrowleaf clover (Trifolium vesiculosum Savi), birdsfoot trefoil (Lotus comiculatus L.), deer milkvetch (Astragalus cicer …
Feeding Value Of The Legume Component In Pasture And Silage,
2026
Victorian Department of Agriculture
Feeding Value Of The Legume Component In Pasture And Silage, K.F M. Reed, P T. Kenny
IGC Proceedings (1977-2023)
Grazing experiments were conducted to examine the feeding value of various pastures for grazing sheep and, in some cases, as silage. Recently, the use of legumes for improving the growth of weaned lambs during the dry summer and early autumn was investigated at Hamilton, Victoria. Studies in Australia showed that the fleeceweights of weaner sheep grazed on eight pasture mixtures of varying grass species increased as the amount of clover in the pasture increased (r -0.88 • *). In a separate study, young sheep grew faster on lucerne· grass pasture than on grass-subtenanean dover pasture. Most recently, live-weight gains of …
Increasing Productivity And Extending Grazing Season Of Cynodon Pastures For Steers With N And Overseedings Of Trifolium And Festuca In The Southeastern U.S.A,
2026
University of Tennessee, Knoxville
Increasing Productivity And Extending Grazing Season Of Cynodon Pastures For Steers With N And Overseedings Of Trifolium And Festuca In The Southeastern U.S.A, H A. Fribourg, J B. Mclaren, R J. Carlisle
IGC Proceedings (1977-2023)
A series of grazing experiments has been conducted 80 km east of Memphis, Tennessee, since 1969 on fine-silty, mixed, ther mic, Typic Hapludalfs soils to evaluate productivity and quality of Cynodon pastures grown with N fertilizer or in combination with Festuca arundinacea and/or Ladino, TnJolium repens, and sometimes with T. pmtense, for growing beef steers. Pastures were grazed by the put-and-take system, and forage growth and consumption were determined by the cage-and-strip method. These experiments have shown that bermudagrass pastures can support many young beef animals for 5 months/yr if they are fertilized with N, can produce rapid gains in …
Simulation Of Complementary Forage Cropping By Feeding Oat Grain To Ewes,
2026
CSIRO
Simulation Of Complementary Forage Cropping By Feeding Oat Grain To Ewes, J L. Wheeler, D A. Hedges, C Mulcahy
IGC Proceedings (1977-2023)
In many parts of the world where year-round grazing is feasible, complementary forages such as oats or sorghum are sown to impove the quantity and quality of the forage available at specific periods. Experiments in which these crops complement wellfertilized grassland have generally not shown an increase in animal production compared with all-grassland systems. The present experiment aimed to determine the effects of a simulated complementary forage crop on pasture yield and on the production of breeding ewes. Eight groups of 10 sheep grazed 0.6-ha plots of Phalaris aquo.tica L.-Trifolium repens L., and eight groups of 10 sheep grazed 0.8-ha …
