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Impact Of Management On Endophyte Free And Endophyte Infected Tall Fescue Cultivars In Ohio, C. D. Penrose, Reuben M. Sulc, J. S. Mccutcheon

IGC Proceedings (1977-2023)

Ten cultivars of tall fescue (Festuca arundinacea, Schreb.) and one cultivar of orchardgrass (Dactylis glomerata L.) were part of a study to determine changes in endophyte levels of fescue under two different styles of forage management: intensive and extensive. Included in the study were two endophyte infected-cultivars of tall fescue to compare interactions with endophyte free and infected cultivars. After three years, the results demonstrate that under high levels of management and non-endophyte infected crops prior to seeding, introduction of the endophyte can be reduced or delayed. Under lower levels of management and a smother crop into …

Grazing Endophyte Infested Tall Fescue And Changes In Bovine Blood Components And Gain, H. A. Fribourg, J. C. Waller, A. E. Schultze, B. W. Rohrbach, J. W. Oliver

IGC Proceedings (1977-2023)

Tall fescue (Festuca arundinacea) is utilized on more than 15 million ha of pasture in the eastern USA and over 80% of the plants in this area are infested with the endophyte Neotyphodium coenophialum. Tall fescue toxicosis results from consumption of the infested (E+) grass host and is an important problem that causes considerable economic loss to producers. However, the agronomic attributes of tall fescue make it an attractive forage because of its ability to withstand cool temperatures, drought, poor soil conditions and intensive defoliation. There is need to understand mechanisms of animal physiology that are affected …

Achievements And Perspectives In The Breeding Of Temperate Grasses And Legumes, Kenneth H. Quesenberry, M. D. Casler

IGC Proceedings (1977-2023)

This paper will focus on a historical perspective on cool season forage production, plant breeding methods for cool season forages, major cool season forage selection criteria, some examples of significant achievements, and a future perspective. Topics similar to ours have been discussed at recent previous meeting of this Congress (Humphreys, 1997; Van Wijk et al., 1993); however, we will strive to avoid “plowing the same ground twice”. In an attempt to prevent duplication of content with other sections of this Congress, only limited attention will be given to genetic resource acquisition and conservation. Additionally, alfalfa (Medicago sativa L.), one …

Achievements And Perspectives In The Breeding Of Tropical Grasses And Legumes, John W. Miles

IGC Proceedings (1977-2023)

Pasture and forage plant breeding is complicated by the perennial nature of the plants, the diversity of environments in which improved cultivars will be used, and the complex criteria of merit involved, criteria that necessarily include some measure of impact on the efficiency of animal production. While pasture plant breeding in the temperate zone is a demonstrably productive activity, the record of success for the tropical species -- "success" measured by release and adoption of bred cultivars -- is less convincing, in spite of four decades of activity in numerous public sector breeding programs and a large published literature. The …

Tropical Forage Genetic Resources -- Will Any Be Left For Future Generations?, B. L. Maass, B. C. Pengelly

IGC Proceedings (1977-2023)

After very active years of pasture and forage research at major institutes, interest in tropical forage genetic resources has drastically declined. Apparently, the early phases of collecting and evaluation were much more valued than conserving and keeping the germplasm available for future generations. Accumulated data are not easily accessible and, therefore, the knowledge of tropical forage genetic resources is progressively being lost. This worldwide decrease in activity and loss of knowledge is due to declining resources. It is suggested that a global database on tropical forage genetic resources should be established and also that finances be made available to at …

Adaptability And Stability Of Alfalfa Cultivars, Ana C. Ruggieri, Alda L. G. Monteiro, R. Gualberto

IGC Proceedings (1977-2023)

Yield adaptability and stability of thirty five alfalfa genotypes (Medicago sativa L.) were evaluated at Sertãozinho, SP, Brazil, considering different environments (seasons of year) from 1996 to 1999. A randomized complete block design with three replications was used. Scott-Knott’s test was performed to compare genotypes averages. Adaptability and stability were determined by Eberhart and Russell's procedures. Two diverse groups of genotypes with mean dry matter yield were identified: Araucana, F686, MH4 e BR2 were more responsive under favorable environments, but SW 8210, Alto, Monarca SP, Victoria SP, Florida 77, P5888, MH15, BR1, BR3, SW 9210A presented broad adaptability and …

Supplementation Of Dairy Cows Under Alfalfa Grazing Conditions With Ground Corn, A. R. Castillo, L. A. Romero, O. R. Quaino, E. A. Comeron, M. C. Gaggiotti

IGC Proceedings (1977-2023)

Two trials were carried out during the Autumn of 1991 and 1992 to investigate the effects of corn supplementation on lactational performance of dairy cows under alfalfa grazing. Forty two multiparous Holstein cows with 30-60 days in milk were used in a randomized continuous design with covariance analysis. The treatments were 0.0, 3.5 and 7.0 kg.day^-1 of corn grain supplementation (T1, T2 and T3 respectively) in 1991 and 0.0, 3.0, 6.0 and 9.0 kg.day^-1 (T1, T2, T3 and T4 respectively) in 1992. Six cows per treatment were used divided in 3 cows per grazing paddock. Dry matter (DM) …

Animal Production From Tree-Pasture Association Systems In Brazil, João C. Saibro

IGC Proceedings (1977-2023)

Agroforestry systems (AFS) in general and silvipastoral systems (SPS) in particular, have been studied intensively in Brazil since the 1980’s. The majority of the research work has been conducted in the wet tropical Amazon region, in the semi-arid conditions of the Northeast, and under subtropical soil and climatic conditions in the Southeast or in the South. Research emphasis has been placed on interactions between the main components of AFS: tree, pasture, soil and microclimatic elements. Evaluation of animal performance in SPS generally has not been the main objective of experiments. A recent survey of research on SPS using Eucalyptus spp …

Multi-Strata Silvipastoral Systems For Increasing Productivity And Conservation Of Natural Resources In Central America, Muhammad Ibrahim, Andrea Schlonvoigt, Juan Carlos Camargo, M. Souza

IGC Proceedings (1977-2023)

Conversion of primary forest to pasture is widespread in Central and Latin America and the progressive removal of trees has resulted in environmental degradation and a decline in productivity, simultaneously threatening rural livelihoods and regional biodiversity. Recently there has been keen interest to develop silvipastoral systems for sustainable animal production. Traditional silvipastoral systems are characterised with a diversity of woody perennials that plays an important role in supplying feed to animals in the dry season, production of timber, shade for animals, and in the conservation of natural resources. Improved novel woody perennials such as Morus alba (mulberry) and Trichanthera gigantea …

Transgenesis And Genomics In Molecular Breeding Of Forage Plants, G. Spangenberg, R. Kalla, A. Lidgett, T. Sawbridge, E. K. Ong, U. John

IGC Proceedings (1977-2023)

Forage plant breeding has been largely based on phenotypic selection following sexual recombination of natural genetic variation found between and within ecotypes. Advances in plant genetic manipulation over the last 15 years have provided convincing evidence that these powerful technologies can complement and enhance plant breeding programs. Significant progress in the establishment of the methodologies required for the molecular breeding of forage plants has been made. Examples of current products and approaches for the application of these methodologies to forage grass and legume improvement are outlined. Large-scale genomic analysis of many organisms is under way with human, arabidopsis and rice …

Opportunities In Molecular Biology: Enhancement Of The Nutritional Value Of Forages, K. R. Hancock, M. J. Ulyatt

IGC Proceedings (1977-2023)

Pasture plants, while producing a cost-effective source of feed for grazing ruminants, can frequently be less than optimal in meeting the animals’ nutrient requirements. Over the past half century, there has been a major effort to improve the quantity and nutritional quality of pasture plants using conventional plant breeding. Although considerable progress has been made in improving the quality and agronomic characteristics of our major pasture plants by this means, breeding can only be applied to plants capable of sexual crosses. This poses severe limitations both in terms of speed of progress and in the number of genes available for …

The Role Of Endophytic Fungi In Brachiaria, A Tropical Forage Grass, S. Kelemu, J. F. White, Idupulapati M. Rao

IGC Proceedings (1977-2023)

In temperate zones, endophytic fungi are widely used as biological protection agents for forage and turf grasses. They form nonpathogenic and intercellular associations with grasses and sedges, completing their entire life cycle within the plants’ aerial parts. Our surveys and studies confirmed that various endophytic fungi, including Acremonium spp., also inhabit native savanna grasses and introduced tropical forage grasses. We are now determining the potentially symbiotic relationships between these fungi and C₄ tropical forages, specifically between the endophyte A. implicatum and Brachiaria grasses. We treated half of a group of genetically identical clones of Brachiaria with fungicide to generate …

Advances In Endophyte Research. Progress And Priorities In Temperate Areas, L. R. Fletcher, H. S. Easton

IGC Proceedings (1977-2023)

Fungal endophytes infect a large number of temperate grass species, genera and tribes (Leuchtmann and Clay, 1997). The majority of these systemic endophytes fall into the genus Epichloe or the closely related Neotyphodium genus.

The asexual Neotyphodium endophytes are asymptomatic, never emerge from between the host grass cells, and are only transmitted vertically, via seed of the host plant. They are believed to have derived from the Epichloe endophytes, (Bacon and White, 2000; Schardl and Wilkinson, 2000) which do emerge from their intercellular habitat and form stromata around the emerging seedhead of their host. This is manifested as the choke …

The Legume – Rhizobia Symbiosis. Does It Vary For The Tropics Relative To The Mediterranean Basin?, J. G. Howieson, A. Mcinnes

IGC Proceedings (1977-2023)

Symbiotic N fixation from legumes is one of the most important biological processes on the planet. It currently provides the majority of the N requirement in agriculture, yet will have to double if cereal crop production is to meet world demand by 2020 (Kennedy and Cocking 1997). To effectively harness the value of biological N fixation from legumes we need to more fully understand G² x E; where G refers to the genotypes of both the legume (G_l) and its microsymbiont (rhizobia; G_r), and E refers to the edaphic environment in which the symbiosis is …

Advances In Forage Legumes: Shrub Legumes, M. H. Shelton

IGC Proceedings (1977-2023)

Forage tree legumes benefit agriculture through their multi-purpose contributions to livestock feeding, to productivity of farming systems, and to protection of the environment.

Of the several hundred forage tree legume species regarded as having potential for forage only c. twenty are in common use. These are listed together with their agroecological range and tolerance of adverse environments including acid soils, cool temperatures, low rainfall, poor drainage and high salinity. The value of many species to ruminants is limited due to low nutritive value arising from low protein availability and low acceptability caused principally by high condensed tannin content. Only 10 …

Alfalfa, J. H. Bouton

IGC Proceedings (1977-2023)

Cultivated alfalfa or lucerne (Medicago sativa spp. sativa) is the most important forage legume in the world with approximately 32 million hectares cultivated mainly in the temperate regions of both the northern and southern hemispheres. Intensive research has been conducted on the management and physiology of the crop and a major seed industry has developed world wide. Since insect and disease pests are numerous in alfalfa, development of cultivars with the proper fall dormancy and a broad genetic base for pest resistance has been pursued in order to provide increased adaptation, persistence, and yield. There has been a …

Yellow-Flowered Lucerne (Medicago Falcata L.) - A Potential Forage Legume For The North, T. Mela, H. Ihamäki, M. Matilainen

IGC Proceedings (1977-2023)

The suitability of yellow-flowered lucerne (Medicago falcata L.) for forage production under the northern conditions was studied in a mixture sward with timothy (Phleum pratense L.) in field trials in South Finland for four years from 1995 to 1998. Through the first three winters lucerne stayed unharmed. In June and July lucerne grew vigorously, but in August little. The total seasonal yields were highest in the second and the third year of harvesting, up to 10 t DM ha^-1. In the winter 1997-1998 , winter damages killed 21 to 38 % of lucerne plants, and resulted …

Role Of White Clover In The Improvement Of Economical Efficiency Of Feeds From Grasslands, P. Goliñski

IGC Proceedings (1977-2023)

The aim of the research was to analyse the role played by white clover in the improvement of economical efficiency of feeds obtained from permanent grasslands. The influence of the proportion of white clover in the pasture sward on unit production costs of yield, energy and crude protein and the profit threshold in milk production was analysed taking into account three white clover cultivars, nitrogen fertilisation, irrigation and overdrilling. The investigation procedures employed the author’s own calculation models elaborated in optimisation programs based on production conditions found in dairy farms in the region of Wielkopolska. It was proved that the …

The Use Of Cafeteria Trials For The Selection Of Desmodium Ovalifolium Genotypes, Axel Schmidt, R. Schultze-Kraft, B. L. Maass, C. E. Lascano

IGC Proceedings (1977-2023)

For the selection of tropical legumes which contain anti-nutritive components such as tannins, relative acceptability of genotypes to ruminants is of particular importance, since these plant components may influence selective grazing behaviour and subsequent animal productivity. Plant-animal interactions are not predictable from laboratory analyses. Involving grazing animals through the conduction of relative-acceptability (=cafeteria) trials at early stages of the germplasm selection process might therefore provide a convenient tool to adjust and confirm genotype selection based on laboratory quality analyses data. As part of a multilocational germplasm evaluation project, cafeteria-experiments were conducted at two contrasting environments in Colombia with a core …

Evaluation Of Brachiaria Brizantha Ecotypes Under Grazing In Small Plots, Valéria P. B. Euclides, Cacilda B. Do Valle, Manuel C. M. Macedo, M. P. Oliveira

IGC Proceedings (1977-2023)

An intense search for new cultivars amongst recently collected and introduced ecotypes from Africa is in effect since 1988, at the National Beef Cattle Research Center, of the Brazilian Agricultural Research Corporation (Embrapa Beef Cattle). After agronomic evaluations of a large collection, 21 ecotypes were pre-selected for multilocational trials and from these, eight were elected for evaluation under grazing. The objective of this trial was thus to evaluate the persistence and carrying capacity of these eight new Brachiaria brizantha ecotypes after two years of grazing. The experimental design was a randomized complete block with nine treatments and two replicates. The …

Agronomic Evaluation Of Alfalfa Cultivars In Rio Grande Do Sul, Brasil, J. C. De Saibro, R. Battisti, T. M. S. Freitas

IGC Proceedings (1977-2023)

From April 1995 to June 1998, thirty five alfalfa (Medicago sativa L.) cultivars (cvs.) were evaluated in a field trial at the “Depressão Central” ecoclimatic region, in southern Brazil. Two years after sowing, 30 cultivars were excluded from the test due to their poor overall agronomic performance, mainly low forage DM yields. The remaining cultivars: Crioula (local genotype used as a check), Victoria, Rio and P 30 are hay-type cultivars while Alfagraze is a grazing-tolerant type. Twenty-two harvests were made and no significant differences were found for total DM yields among cvs. Crioula, Victoria, Rio and P 30; however, …

Evaluation Of Paspalum Spp. With Adaptation To Poorly Drained Soils In The Tropical Americas, Michael Peters, B. Hincapié, P. Avila, C. E. Lascano

IGC Proceedings (1977-2023)

A collection of Paspalum accessions obtained from Brazil was tested for their adaptation to poorly drained soils. Three accessions were selected based on their DM production and nutritive value. Productivity and quality of these three accessions was stable over the periods of maximum and minimum rainfall, giving potential for continuous forage supply throughout the year in the tropical Americas. Grazing trials for the selected accessions are underway.

Intake Characteristics And Performance Of Contrasting Grass Varieties Continuously Stocked With Sheep, R. J. Orr, J. E. Cook, R. A. Champion, A. J. Rook

IGC Proceedings (1977-2023)

Fifteen intermediate-heading perennial ryegrass (Lolium perenne) varieties were grazed by sheep under continuous variable stocking management. Mean daily grass dry matter intake per ewe was positively correlated with liveweight gain per ewe (r = 0.63) and per ha (r = 0.58) over an 8-month grazing season. Daily intake was not correlated with grazing time (r = 0.12) but was positively correlated with instantaneous dry matter intake rate (r = 0.75). Breeding varieties with high intake rate characteristics should allow increases in the contribution of grazed grass to grassland-based livestock farming. There is now a …

Variability For Nitrogen And Phosphorus Uptake Among Timothy Genotypes, Réal Michaud, Gilles Bélanger, A. Brégard

IGC Proceedings (1977-2023)

Cultivars of timothy (Phleum pratense L.) with high N and P use efficiencies are required to reduce costs of production and risks of N and P pollution, and to meet the nutrition requirements of high producing animals. This field study aimed at comparing, (under three N rates) the relationship between DM yield, N uptake, and P uptake of 27 timothy half-sib families, plus the cultivar Champ as a control (Dry matter yield), N and P uptake increased with increasing N rates. Genotypes also differed for DM yield, N and P uptake. For a given DM yield, the genotypes had …

Research On Forage Quality: Progress And Priorities, J. A. Milne

IGC Proceedings (1977-2023)

A broad definition of forage quality is used and the purposes for which research on forage quality is undertaken currently are outlined. These range from research that provides simple measurements that describes the forage quality of a commercial product to research on forage quality to improve understanding of digestion processes. Much of the research in the last decade has related to improving predictive measurements. The different degrees of progress that have been made in the development and use of measurements to further our understanding of forage quality are described and related to their fitness of purpose. It is concluded that …

Forage Quality And The Environment, C. E. Lascano, A. Schmidt, R. Barahona

IGC Proceedings (1977-2023)

The influence of environmental factors on forage quality of temperate and tropical grasses has been reviewed by several authors, who summarized how light, temperature, drought and soil nutrients influence chemical composition, and digestibility of forages grown in contrasting areas of the world. The effects of season of the year on forage growth, grazing behavior and animal performance have also been the subject of numerous papers and reviews. However, there are few recent reviews that summarize how changes in climatic and edaphic factors influence forage quality of legumes with variable levels of condensed tannins (CT), which are important secondary compounds in …

Screening Fresh Forages For Protein Degradation And Nutritive Value, Garry C. Waghorn, J. L. Burke

IGC Proceedings (1977-2023)

A method has been developed to prepare fresh forages for in sacco and in vitro incubation by freezing and mincing to achieve a particle size distribution of dry matter (DM) similar to in vivo conditions. The method is described and data presented to indicate losses of nitrogen (N) during in sacco digestion and net yield of ammonia from proteolysis in vitro for 22 fresh and conserved forages. Grasses, legumes and herbs were evaluated, with fractional degradation rates of forages ranging from 0.07h^-1 with tall fescue (Festuca arundinacea) to 0.24 h^-1 with chicory (Cichorium intybus). …

Evaluation Of Ten Tropical Grasses In The Northwest Region Of The State Of São Paulo-Brazil, C. V. Soares Filho, L. R. De A. Rodrigues

IGC Proceedings (1977-2023)

The experiment was carried out in the northwest region of the State of São Paulo-Brazil to evaluate ten grasses recently introduced in the region. The grasses studied were: Cynodon nlemfuensis cv. Tifton 68, C. dactylon cv. Tifton 78, Cynodon spp. cv. Tifton 85, C. dactylon cv. Florakirk, C. nlemfuensis cv. Florico, C. nlemfuensis cv. Florona, C. dactylon cv. Coastcross, Paspalum notatum cv. Tifton 9, Brachiaria brizantha cv. Marandu, Panicum maximum cv. Tanzânia 1. The following variables were determined: DM production, growth rate, IVDMD, CP, ADF and NDF.

The GRs varied from 81 to 102 and from 14 to 26 Kg …

Evaluation Of Centrosema Rotundifolium For Sand-Soil Savannas In Eastern Venezuela, I. Rodríguez, R. Schultze-Kraft, S. González

IGC Proceedings (1977-2023)

An evaluation of a collection of amphicarpic Centrosema rotundifolium showed considerable variability among the six accessions tested, regarding above- and below-ground seed production. Dry-season forage yields were very low but rainy-season yields reached acceptable levels. Contents of crude protein, P and Ca were intermediate to high (CP and P) or low (Ca). Three accessions are suggested for on-farm testing in association with grasses in order to explore the plant persistence implications of belowground seed production under practical conditions. Furthermore, the potential of this amphicarpic species for the conservation of sandy soils deserves attention.

Genetic Resources For Tropical Areas: Achievements And Perspectives, Cacilda B. Do Valle

IGC Proceedings (1977-2023)

This paper analyses the present status of tropical forage resources and their utilization in the development of novel cultivars based on the accumulated information from past decades of collecting, evaluation and whatever little breeding has been pursued. The situation of world collections of tropical forages is presented and discussed in the light of limited investment and dwindling resources. A cause for concern is the lesser priority assigned to conservation and manipulation of official tropical germplasm banks, such as CSIRO’S and CIAT’s. In order to assure the availability of tropical genetic resources for the future it is imperative that international efforts …