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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. …

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, 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 …

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, 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, 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 …

Effect Of Feeding Level And Forage: Concentrate Ratio On The Digestibility Of Pelleted Diets By Sheep And Cattle, G.M J. Horton, M J. Farmer, B E. Melton, S Sklane

IGC Proceedings (1977-2023)

Sheep are frequently used to determine the nutritive value of cattle feeds. However, there is some evidence that digestion coef­ficients for cattle and sheep may differ and that digestibility may be influenced by feeding level. The purpose of this study was to investigate the effects of feeding level and animal species on the digestibility of pelleted diets containing different ratios of alfalfa hay to barley grain. Five 4O-kg yearling crossbred lambs and four 35O-kg yearling steers were used to evaluate each diet. The six diets were isonitrogenous, containing the following proportions of barley grain and alfalfa hay (percentage as fed …

Effect Of Supplements On The Live-Weight Gain Of Beef Cattle Given Forage During The Dry Season, C Thomas, P N. Mbugua

IGC Proceedings (1977-2023)

The low quality of standing pasture grasses in the dry seasons presents a major problem in the intensification of beef produc­tion in the tropics. The objective of this research was to examine the role of maize and grass silage or standing napiergrass (Pen­nisetum purpureum) as sources of forage when given alone or with supplements to beef cattle. In the first of three trials conducted at the National Agricultural Research Station, Kitale, Kenya, 36 Friesian castrates, initially 249 kg live weight (LW), were given silage of whole-crop maize either alone or supplemented with corn-and-cob meal. Each of these two basal diets …

Utilization Of Energy Of Fresh Pasture By Lactating Dairy Cows, T E. Trigg, C R. Parr, N R. Cox

IGC Proceedings (1977-2023)

The New Zealand dairy industry is almost totally reliant on grazed herbage for the production of milk solids, but few data ex­ist on the efficiency with which lactating cows utilize energy of fresh herbage offered as the sole diet. One hundred thirty-two energy balances have been conducted by indirect calorimetry using cows at two levels of feeding and at two stages of lactation over 3 years. Mixed pasture suitable for grazing and cut twice daily was the sole diet. Data for the utilization and partitioning of energy have been subjected to regression analysis on a within-cow basis. Efficiency of utilization …

Energy Balance Studies With Lactating Cows Fed Fresh Or Frozen Grass From Pasture Suitable For Grazing, Y Van Der Honing, A.J H. Van Es

IGC Proceedings (1977-2023)

Information on feeding value and energy utilization of grass consumed by grazing cattle, especially lactating cows, is limited. It is nearly impossible to perform calorimetric studies with grazing dairy cows. Similar studies indoors often show low intakes of fresh grass and require much labor. Still, in much of the world, cattle graze at least half the year; therefore, knowledge of the feeding value of grass is important for practice. In the Netherlands, each year (1973-1974) each of four permanent pastures in the grazing stage of maturity was cut twice daily and either fed fresh or stored at - 20°C to …

Seasonal Changes In Botanical And Chemical Composition And Digestibility Of Diets Of Large Herbivores On Shortgrass Prairie, G M. Van Dyne, J D. Hanson, R C. Jump

IGC Proceedings (1977-2023)

Studies were conducted from 1969 through 1974 on northeastern Colorado shortgrass prairie during different grazing seasons and under different grazing intensities to evaluate bison, cattle, sheep, and pronghorn antelope diets. The purpose was to ex­amine seasonal changes in chemical and botanical composition and digestibility of diets of large herbivores. Bison, cattle, and sheep diets were obtained from esophageal fistula samples. Fistula samples were analyzed microscopically to determine botanical composition. Pronghorn antelope diets were obtained by bite-count methodology. Data, presented for im­portant plant species and species groups, were averaged for 28-day intervals to show typical seasonal trends in diets. During all …

Cattle Preference And Plant Selection Within A Hybrid Grass, P O. Currie, R S. White, K H. Asay

IGC Proceedings (1977-2023)

Recent development of hybrid forage grasses shows promise for advancing grassland agriculture. Previous selections within these hybrids have been based on morphological, reproductive, and adaptive attributes with only limited testing of animal ac• ceptability. Testing of animal preference and selectivity was the primary purpose of the present study. Yearling cattle were tamed and observed for their selectivity in grazing individual plants and genetic lines of F6 crosses between quackgrass (Agropyron repens) x bluebunch wheatgrass (Agropyron spicatum). Animals showed definite preference for individual plants within genetic lines and for different genetic lines. Different animals frequently preferred the same plant or lines …

Combination Range-Pasture Management In South Florida For A Low-Energy Grassland Program, L L. Yarlett

IGC Proceedings (1977-2023)

The semitropical environment of south Florida is favorable for coordinated management of a wide variety of native grass species and improved pasture forages. The decade of the 1980s will emphasize change from forage programs of high energy utilization to those with a low requirement of fossil fuels. For 4 decades, grassland management in south Florida has been primarily pasture establishment created from the rangeland resource. The establishment and management required substantial inputs of fossil fuel. Use and management of rangeland was largely neglected. Ecological concepts as a basis for managing semitropical ranges were not accepted. In recent years practical programs …

Forage Intake Of Cattle As Affected By Grazing Pressure, C D. Allison, M M. Kothmann, L R. Rittenhouse

IGC Proceedings (1977-2023)

A series of trials was conducted in 1977 to determine the effect of level of grazing pressure on organic-matter intake and the relationship between intake and forage disappearance. Levels of grazing pressure studied were 10, 20, 40, and 50 kg forage allowed/animal unit/day (kg/AU/day) for 14-day trials in April, July, and September. A standing crop of forage was measured before, in the middle of, and immediately after each trial. Organic-matter intake was estimated by the fecal output: indigestibility ratio technique. Organic-matter intake was highest in April; cattle also consumed Dlore forage in September than in July. The combination of forage …

Effect Of Herbage Mass And Allowance Upon Herbage Intake By Grazing Dairy Cows, J.A C. Meijs

IGC Proceedings (1977-2023)

An adequate supply of nutrients for grazing animals depends on the intake and nutritive value of herbage. Little information is available on factors affecting herbage intake of grazing cows, particularly for grazing systems that do not involve daily change of animals to a new pasture. Our objectives were to determine the effects of variation in herbage mass ( due to variation in stage of maturity) and of herbage allowance on herbage intake by grazing dairy cows and on efficiency of consumption (herbage con­sumed as a proportion of herbage accumulated). From 1976 to 1979 the herbage intake oflactating cows was determined …

Relation Of Animal Production To Stocking Rate On Cultivated Pastures In Cerrados Areas Of Brazil, C J. Escuder

IGC Proceedings (1977-2023)

The relationships among stocking rate, gain/animal, and gain/ha were compared on six grazed pastures. The experiment was established on an oxisol acrustox in Brazil. The pasture consisted of (1) jaraguagrass (J); (2) jaraguagrass plus legumes (J + L); (3) molassesgrass (M); (4) molassesgrass plus legumes (M + L); (5) pangolagrass (P); (6) Pangolagrass plus legumes (P + L); (7) mixture of grasses (jaragua, molasses, and pangola) plus legumes (JMP + L). Pasture of pangolagrass alone was discarded because of poor establishment. Four stocking rates were applied on each pasture, from 1.0 to 3.4 animals/ha. For all pastures, gains/animal decreased linearly …

Harvesting And Processing Effects On Alfalfa Protein Utilization By Ruminants, R Britton, D Rock, T Klopfenstein, J Ward, J Merrill

IGC Proceedings (1977-2023)

Alfalfa (Medicago sativa) is an efficient and important means of producing supplemental protein for ruminants. This research was undertaken to characterize the value of alfalfa protein for ruminants and to show how the protein is affected by different harvesting or processing regimens. The effects of maturity (prebloom, one-tenth, one half, and full bloom) and processing method (freeze dried [FD], sun cured [SC], and oven heated [HJ), on percentage of nitrogen (N), acid detergent insoluble N (ADIN), in-vitro rumen ammonia release (NH3), and in-situ rumen protein degradation, using dacron bags (BAG), were studied on irrigated alfalfa harvested over 2 years. …

Improving Hay Quality By Ammoniation, K J. Moore, V L. Lechtenberg, K S. Hendrix, J M. Hertel

IGC Proceedings (1977-2023)

Experiments were conducted to determine the effect of hay ammoniation on hay consumption and weight gain by steers when the hay was fed unsupplemented and supplemented with energy and protein. Mature orchardgrass (Dacrylis glomerata L.) hay was baled in early June 1979 and treated with anhydrous ammonia at 30 g/kg of hay. Seven weeks after treatment the hay was uncovered and allowed to aerate for 3 days. It was then fed to weanling steer calves weighing approximately 225 kg each. Similar hay baled from the same field but not ammoniated was fed to separate groups of steers. Both the treated …

Effect Of Solvent Treatments On Intake And Digestibility Of Corn Stover, D M. Schaefer, M R. Ladisch, C H. Noller, V L. Lechtenberg

IGC Proceedings (1977-2023)

Treatment of crop residues with low levels of sodium hydroxide has been shown to improve organic-matter digestibility and animal performance. One objective of these experiments was to evaluate the effects of three treatments -water, sodium hydrox­ide, and chelating metal cellulose-swelling solution-on solubilization of cell-wall components in corn (Zea m£rys) stover. The two latter treatments were balanced for level of sodium hydroxide application, which was .3 .2 % of stover dry matter. The second objective was to determine the effects of these treatments on in-vitro and in-vivo digestibility as well as on consumption of corn stover. Twelve growing ram lambs were …

Fate Of Nitrogen Applied To Grassland In Animal Wastes, M Sherwood

IGC Proceedings (1977-2023)

The experiment was designed to determine the effects of land spreading of animal manures on the nutrient content of surface runoff water and infiltrating soil water. This report deals only with nitrogen (N) and attempts to quantify the losses through runoff, leaching, and volatilization of ammonia (NH3) as well as N uptake in the grass over a 3-year period. Experimental plots sited on grassland, on two soil types (a moderately drained loam and an impermeable gley), were equipped to collect surface runoff water. Ceramic probes were installed in each plot at 15-, 30-, 60-, and 100-cm depths to extract in­filtrating …

Nitrogen Losses From Urine-Affected Areas Of A New Zealand Pasture, Under Contrasting Seasonal Conditions, P R. Ball, D R. Keeney

IGC Proceedings (1977-2023)

Grazing ruminants aggregate large quantities of forage nitrogen (N) into urine patches. Pasture plots treated with urine N were studied to assess its fate under contrasting seasonal conditions: cool-moist (representing winter-spring); warm-moist (late spring-early summer), and warm-dry (late summer-autumn). A permanent ryegrass (Lolium perenne L.)-white clover (Trifolium repens L.) sward on free-draining alluvial soil was studied. 'freatments were replicated in randomized blocks. Urine N was applied at 30 or 60 g N/m2• Relevant measurements were then continued until treatment differences disappeared. Apparent N balances for urine treatments were compiled. Fixation by white clover was always greatly reduced in …

Effects Of Water Stress On Herbage Quality, J R. Wilson

IGC Proceedings (1977-2023)

Uncertainty exists about whether drought is detrimental to the nutritive quality of herbage. This paper tries to resolve this uncertainty by examining the influence of soil moisture on some herbage-quality characteristics. Unpublished data from my own work and review of published literature are presented. Field plots of three tropical grasses, green panic (Panicum maximum var. trichoglume), buffelgrass (Cenchrus ciliaris), and speargrass (Heteropogon contortus), were subjected to perioqs of controlled drought, and herbage from these plots was compared with that from well-watered plots. Leaf and stem dry-matter ?igestibility of water-stressed herbage was either similar to or higher than that of unstressed …

Consumption Rates And Desert Grassland Herbivores, R D. Pieper

IGC Proceedings (1977-2023)

Studies were conducted on a desert grassland range in southern New Mexico for 3 years to determine relative consumption rates of the main herbivores utilizing these range areas. Consumption of some groups (cattle, pronghorn antelope, and rabbits) was determined from direct estimates of intake/individual, and density was determined from censusing procedures or known stock rates. Consumption by other groups (birds, rodents, and invertebrates) was determined from census information relating to age structure of the population and metabolic rate. Consumption by all herbivores averaged less than 5 % of the above-ground net primary productivity for the 3 years of the study. …

Performance Of A Subtropical Legume-Grass Pasture Under Different Grazing Management Systems, G E. Maraschin, S C. Mella, G S. Irulegui, J Riboldi

IGC Proceedings (1977-2023)

Agronomic evaluation of the dynamics of tropical legume-based pastures is relevant in assessing the response of their com­ponents within systems of grazing management. The response of tropical legume-grass mixtures to periods of rest and grazing pressure and the combinations that result in meaningful legume content in the mixture need to be known. A central composite design was used to study the performance of a Desmodium intortum (Mill.) U rb. and Paspalum gttenoarum Arech. pasture mixture to 14, 28, 42, 56, and 70daysofrestcombinedwith 2.0%, 3.5%, 5.0%, 6.5%, and 8.0% BW(i.e., kg dry matter (DM) on offer/day/100 kg body weight) as grazing …

Legume Establishment In Grass-Dominant Swards: Concept And History In Kentucky, T H. Taylor, W C. Templeton Jr

IGC Proceedings (1977-2023)

Grassland farming has been practiced for 2 centuries in central Kentucky and for shorter periods in other parts of the state. Savannas and tallgrass prairies were severely grazed by domestic animals and row-cropped by early settlers, destroying most of the indigenous plant species. By the early part of the 19th century, beef cattle were being produced on bluegrass (Poa pratensis L.) pastures and driven on foot to east-coast markets. During the first century of settlement, farmers learned to top-seed legumes into grass sods, and in the course of the last hundred years development of grassland technology for establishing legumes …

Seed And Seedling Dynamics Of Annual Medic Pastures In South Australia, E D. Carter

IGC Proceedings (1977-2023)

Annual species of Medicago (i.e., medics) are the key to successful cereal-pasture rotations in the integrated crop-livestock farming systems on the neutral to alkaline soils of southern Australia. However, many medic stands have deteriorated in recent years. This deterioration has prompted research on the effects of grazing sheep on the seed-seedling dynamics of annual medic­based pastures in the Mediterranean environment of South Australia, aiming to quantify the impact of medic seed reserves in or on the soil upon pasture establishment and productivty.

Animal-house experiments involving the feeding of purepod and pod-chaff diets to sheep and a field experiment have been …

Physiology Of Growth Of A Grazed Sward, E L. Leafe, A J. Parsons

IGC Proceedings (1977-2023)

To improve our understanding of grassland utilization under grazing, the physiology of a grazed sward was investigated. An enclosure method, infrared gas analysis, and radiocarbon were used to measure sward and single-leaf photosynthesis and assimilate utilization. Intake by sheep was also measured. Expanding and recently expanded leaves had high rates of net photosynthesis but leaf sheaths, whose projected area in a "hard" grazed sward equaled that of the lamina, had low efficiency and contributed little to canopy photosynthesis. But because high leaf efficiency did not compensate for the small leaf area, canopy photosynthesis decreased markedly as grazing intensity increased. Twice …

Grassland Development In The Southern Highlands Of Peru, E J. Stevens, P Villalta

IGC Proceedings (1977-2023)

This paper describes grassland development in Peru. Vegetation of the high alpine region of Peru, which occupies some 4 million ha, is dominated by native grasses normally producing less than 2,000 kg/ha dry matter annually. On land with ade­quate soil moisture, pastures based on perennial ryegrass (Lolium perenne L.) and white clover (Trifolium repens L.) were established successfully, but on drier sites alfalfa proved superior, producing over 12,000 kg/ha/yr in some trials. Alfalfa and clovers were also successfully introduced into improved native pastures by mechanical direct seeding and by hand sowing. With direct seeding, dry-matter production increased from about …

Pasture Evaluation In The Desertic Zone Of Venezuela For The Development Of Goat Production, A Gallardo, A Leone

IGC Proceedings (1977-2023)

The desertic zone of Venezuela is an area of approximately 4.1 million ha that represents 4.8 % of the total national territory, on which there are two million goats. Goats represent the main, if not the only, income source for 60,000 rural families. According to UNESCO (1973), the desertic zone of the country comprises two vegetation types, evergreen scrub and deciduous scrub. In each of these zones the plant species consumed by goats were collected and, for those plant parts consumed by the animals, chemically analyzed to determine nutritive value. Forage plants from other tropical countries were also in­troduced and …

Evaluation Of Biological Components In Decision-Making In Forage Allocation, J E. Skiles, G M. Van Dyne

IGC Proceedings (1977-2023)

Forage allocation to mixtures of large herbivores is accomplished by minimizing the difference between the available herbage and the required forage for animals on rangeland. Availability is determined in part by the plant's physiological tolerance to grazing or its allowable-use factor and the animal preference for that plant, measured in part by the proper-use factor. The mix of large herbivores on the rangeland must also be considered. The grazing requirements for animals are dependent on animal preference for plant species and on the total forage intake rates. This paper presents an analysis of these concepts and published information. The concept …