Plant Pathology Commons^™

Forage Production And Nutritive Value Of Cynodon Spp. Under Grazing In Puerto Rico, L E. Tergas, Y Q. Cabrera, A Sotomayor Rios

IGC Proceedings (1977-2023)

Livestock production in the tropics is highly dependent on forages to meet the nutritional requirements of grazing cattle. However, seasonal fluctuations on dry matter production and nutritive value are limiting factors affecting animal perform­ance and production. Stargrass Cynodon nlemfuensis var. nlemfuensis is a highly productive grass recommended for intensive management in the humid tropics of Puerto Rico (Vicente-Chandler et al., 1974). Bermuda Cynodon dactylon and Stargrass produced high yields of quality forage and persisted under intensive grazing in the humid northern coastal plains of Puerto Rico; however, the average production of both grasses was related to rainfall distribution, decreasing during …

Prediction Of The Yield Of Nutritive Matter In Some Autumn Cut Forage Catchcrops, K Kastelic, J A. Nikolic, A Pavlicevic, T Stupica, J Cizec

IGC Proceedings (1977-2023)

Arable land often lies fallow for a time, which provides an opportunity for growing fodder catchcrops between two main crops. This practice should improve the soil structure, conserve soil moisture, eliminate many weeds, maximise land use and enable easier preparation for the subsequent main crop. More­over, subsequent cereal yields may be increased by preceding forage legume crops (Papastylianou and Samios, 1987). The aim of present investigation was to determine the concentration of promising autumn cut catchcrops (D-value) and to assess the possibility of predicting the yield of digestible organic matter (DOM) from the yield of green or dry matter (DM).

Changes In Digestibility With Regrowth Of Some Temperate Grasses, K Watanabe, S Furukawa, A Sato, S Saiga

IGC Proceedings (1977-2023)

Many workers have reported that the decline in digestibility of temperate grasses were steep after heading in 1st cut and lenient during the regrowth in 2nd and 3rd cuts. But in some grasses, heading is observed even in 2nd and 3rd cuts, and the late stages of regrowth were sometimes accompanied by high temperature which usually accelerate the decline in digesti­bility. So even in the regrowth, digestibility is one of the important factors to optimize cutting stage of grasses. Cutting stages in the regrowth of grasses have been discussed from the standpoint of dry matter production (Watanabe et al., 1984; …

Feeding Behavior Of Bali Cattle Fed Gliricidia Diet, K Lana, I M. Nitis, S Putra, M Suarna, W Sukanten

IGC Proceedings (1977-2023)

Even though Gliricidia sepium has been used as fodder in the tropics, the extend of its utilization by ruminant is not well documented (NFTA, 1987). When mixed with other forages, Gliricidia sepium consumption by Bali cattle can be as high as 50 % during the wet season and increases up to 66 % during the dry season (Nitis et al., 1988). The presence of inhibiting substances has been suggested to cause the low palatibility of the Gliricidia leaf (Cheeke and Raharjo, 1987; Rodriguez et al., 1987). The objective of this experiment was to study the preference of Bali steer on …

Electronic Measurement Of Grazing Time And Intake In Free Roaming Livestock, J R. Forwood, M M. Hulse

IGC Proceedings (1977-2023)

Herbage intake is one of the critical factors in understanding why livestock perform at various levels on different forages, however acceptable methods of measuring voluntary intake of free-roaming livestock are still lacking. Commonly used indirect measurement methods estimate pasture herbage loss or animal gain, fecal output and digestibility equations, grazing behavior calculations or indicators (Greenlaugh, 1982). More direct attempts of measuring intake include the Animal Weight Telemetry System (AWATS) of Horn and Miller (1979), multiple impedance plethysmography (Stuth et al., 1981) and the conductivity transducing cannula (CTC: Forwood et al., 1985). With new technology becoming avail­able in smaller, more affordable …

Pasture Species Preferences By Horses In New Zealand, W F. Hunt, R.J M. Hay, D Clark

IGC Proceedings (1977-2023)

The equine breeding industry of New Zealand makes a con­siderable contribution to the export earnings, but the pro­duction base of that industry, i.e. the equine pastures have been neglected by our researchers. Thoroughbred studs are estab­lished on ex-dairy or ex-sheep farms which are usually sown with perennial ryegrass and white clover. Ryegrass based pastures can be highly productive, but in New Zealand suffer from the Argentine stem weevil - ryegrass staggers dilemma. i.e. Low endophyte ryegrasses do not survive Argentine stem weevil, but resistant high-endophyte ryegrasses cause the ani­mal muscular disorder« ryegrass staggers». The seasonal pro­ductivity pattern of ryegrass is …

La Consommation De Matiere Sche De Fourrages Disponibles En Zone Tropicale, D Richard, H Guerin, G Roberge, D Friot

IGC Proceedings (1977-2023)

Un certain nombre de publications fournissent des donnees sur les consommations de matiere seche (MS) des fourrages dans les regions intertropicales sans qu'il soit toujours possible de differencier les variations liees a la capacite d'ingestion de !'animal ou a l'ingestibilite du fourrage, facteurs conditionnant les quantites de matiere seche volontairement ingerees (MSVI). Par ailleurs, les donnees publiees pour un meme fourrage sont souvent tres variables ; par exemple, les quantites de MSVI de Digitaria decumbens extraites de 5 publications varient de plus de 40 p. 100 pour des repousses de meme age (Richard, 1987) sans qu'il soit possible d'identifier les …

Particulate And Fluid Retention Times In Sheep As Influenced By Forage Morphological Composition And Intake, D J.R Cherney, D R. Mertens

IGC Proceedings (1977-2023)

Production by ruminants on high forage diets is often limited by intake. If fill limits intake, residue must escape the rumen through digestion or passage for further intake to occur. Resistance to escape of forage residues from the rumen is a function of physical and morphological characteristics of the forage, although the nature of the relationship is not fully understood (Moseley and Jones, 1984). Understanding of factors affecting passage of undigested residue is important to ensure maximum forage utilization in ruminant diets. It was hypothesized that differences in forage morphological composition, particle length and rates of passage of morpho­logical components …

Responses In Ingestive Behavior By Sheep Changes In Sward Structure, P D. Penning, A J. Parsons, G E. Hooper, R J. Orr

IGC Proceedings (1977-2023)

Recent work has shown how herbage growth, ingestive behaviour and herbage intake may be related to sward height under continuous stocking (Parsons et al., 1986; Penning, 1986). However, the application of these relationships to other grazing managements, where differences in herbage mass, tiller number and leaf to stem ratio at the same sward heights occur, have not been considered. The objective of this study was to determine the major factors affecting ingestive behaviour and intake of herbage by sheep grazing swards differing in structure and morphology but with similar heights.

Factor Affecting The Eating Rate Of Forage Feeds, G Moseley, A Antuna Manendez

IGC Proceedings (1977-2023)

The total amount of a forage feed eaten by an animal may be regarded as the product of rate of eating and time spent eating. Balch and Campling (1962) suggested that it is controlled largely by the rate at which the forage can be broken down phy­sically and passed through the foregut. Differences in voluntary

intake between forage feeds may, however, be due to the effects of extrinsic factors such as environment, animal condition and feed presentation, or to inherent feed characteristics which con­trol the rate and extent of breakdown and digestion. The degree to which physical plant characteristics may …

Influence Of The Nature Of Hay On Its Ingestibility And The Kinetics Of Intake During Large Meals In Sheep And Cows, R Baumont, J P. Brun, J P. Dulphy

IGC Proceedings (1977-2023)

Ingestibility is the quantity of a forage that can be eaten by a standard animal when it is fed ad libitum as the sole feed (INRA, 1978). The eating pattern of ruminants reflects the way in which intake is controlled. The animal eats a large meal when a new batch of forage is distributed ; meals thereafter are small until the next distribution (Dulphy & Faverdin, 1987). To make a closer study of forage ingestibility, it seemed interesting to record the daily pattern of intake and to analyse in detail the large meals, which are 60 to 90 % of …

Relative Palatability Of Some Little-Known Tropical Forage Legumes, R Schultze-Kraft, C Lascano, G Benavides, J M. Gomez

IGC Proceedings (1977-2023)

In preliminary agronomic evaluations some of the little­know legumes recently selected in Southeast Asia have shown good adaptation to an acid, low-fertility Ultisol (CIAT, 1984, 1985). It is recognized that early evaluation of forage species should include an assessment of relative palatability (Joblin, 1962), particularly for tropical legumes where some species have been found to be highly unpalatable to cattle (Warmke et al., 1952). This paper reports on two cafeteria grazing trials conducted to assess the relative palatability of some new Southeast Asian legume germplasm as well as some South American species and ecotypes assumed to be of low palatability.

Fiber Composition Of Successive Cuts Of Lucerne, D Kolarski, J Pavesic-Popovic,, O Krstic, K Koljajic

IGC Proceedings (1977-2023)

The plant cell walls contain lignin, cellulose, hemicellulose, fiber bound protein and fiber bound minerals. Their nutritive value is limited by their degree of lignification, while cell con­tents is not limited (Barton et al., 1977). Type and extent oflig­nin-polysaccharide bounding could affect digestion more than amount of lignin (Jung et Fahey, 1983). The purpose of these studies was to determine chemical and fiber composition of four cuts of lucerne (Medicago sativa, CV Kl).

Relationship Between The Mineral Content In Pastures And The Content Of These Elements In Blood Serum In Dairy Cows, A Lachowski, I Kuczynska, W Wojciechowski

IGC Proceedings (1977-2023)

Grass tetany, a conditioned Mg deficiency of improper K: (Ca + Mg) ratio is a nutritional problem in various parts of Poland. The aim of the investigations was to determine to what degree the mineral content of grasses in the pastures influenced the mineral content in blood serum in dairy cows. This is very important when the animals are grazing and when cattle slurry is used on grasslands. In the literature we can find opinion con­sidering hypomagnaesemia as a metabolic disorder of rumin­ants typified by low blood serum Mg and generally accompanied by hypocalcemia. It has been related to low …

Etude D'Un Facteur Antinutritionnel De La Luzerne: Les Saponines, M Lila, G Genier, W Pietraszek

IGC Proceedings (1977-2023)

Les proteines de luzerne (Medicago sativa) extraites par des procedes industriels ne peuvent etre incorporees qu'en faible proportion dans les rations pour monogastriques a cause d'un effet antinutritionnel du essentiellement a la presence de sapo­nines et plus particulierement d'acide medicagenique (Pie­traszek, 1985). La technologie d'extraction ne permettant pas d'eliminer ces molecules, il a ete envisage d'ameliorer la qualite de ces proteines extraites par la diminution de la teneur dans la plante par voie genetique. Pour cela il fallait etudier la variabilite genetique disponible au sein de l'espece Medicago sativa et definir un test rapide per­mettant de discriminer en grande serie …

Mineral Composition Of Grasses Grown On Peat Soils In Northwestern Hungary And Fertilization Experiments. Manganese, R Schmidt, J Varga, G Tolgyesi

IGC Proceedings (1977-2023)

The main goal of these experiments which were carried out for four years was to study the mineral composition of grasses grown on peat soil, where preliminary studies indicated manga­nese, copper and zinc deficiency. We tried to eliminate these deficiences by agrochemical methods, because in our opinion, intervening in the first part of the foodchain - in the soil - we can contribute to solving of the deficiency problems more fund­amentaly (Ti:ilgyesi et al., 1983).

Characterization Of Biological Properties Of Fodder Value Of Dandelion, Taraxacum Officinale Web., M Falkowski, I Kukulka, S Kozlowski

IGC Proceedings (1977-2023)

In recent years the quantities of dandelion appearing on newly established grasslands has increased quite significantly. In such conditions it can no longer be treated as a meadow herb whose fodder value, according to European literature, equals half of that of valuable fodder plants. Becoming a weed, dan­delion has been the object of investigations on ways of elimina­ting it from the sward by means of herbicides (Schlotter et al., 1988). At the same time, experiments are under way on biologi­cal properties of dandelion with the aim to explain the causes of its expansion. It was found that there is an …

Location Of Polyphenols In Leaves Of Serciea Lespedeza, C O'H Mosjidis, C M. Peterson, J A. Mosjidis

IGC Proceedings (1977-2023)

Preliminary studies in sericea lespedeza, a nonbloating for­age legume, indicated that its palatability and digestibility were reduced by high levels of phenolics (Clarke el al., 1939). Another study suggested that younger parts of the shoots are more palatable than older leaves and stems (Donnelly el al., 1971). Nevertheless, younger leaves have been reported to con­tain higher levels of phenolics (Burns, 1966). Polyphenols have been thought to play a role as growth regulators and in protection against insects and diseases. Also they seem to be associated with lignification (Salatino el al., 1988). The present study was performed to determine whether his­tological …

Effect Of Endophytic Fungus Infection, Water Stress And Genotype On K, Ca And Mg Concentration Of Fescue, S R. Wilkinson, D P. Belesky, W C. Stringer

IGC Proceedings (1977-2023)

Replacement of endophyte infected tall fescue with endo­phyte free tall fescue is recommended to avoid tall fescue toxi­cosis. Fribourg et al. (1988) suggest that the endophyte may enhance tolerance of tall fescue to environmental stresses, including drought. This controlled environment study was undertaken to determine the effect of water stress on the K, Ca and Mg concentration of four genotypic selections of tall fescue with and without fungal endophytes. This paper emphasizes water stress and endophyte effects. The growth characteristics are reported elsewhere (Belesky et al. 1989).

Effect Of Fertilizers On Cutting On Time On Chemical Composition Of Sward From Permanent Meadow, A Golob, Zdenka Berloznik, M Leskosek, Vekoslava Stibilj

IGC Proceedings (1977-2023)

Ecological problems and surpluses of milk and meat have given rise to less intensive systems of grassland utilisation. One of such system is utilisation of air nitrogen via legume sym­biosis with nitrogen fixing bacteria. In Slovenia, where conditions for legume growth are more favourable than in NW Europe, natural meadows fertilized with P and K only give reasonable yields - on average around 7 t DM per ha (Leskosek, 1981). Most legumes suffer after fre­quent defoliation so such meadows should be defoliated only 2- 3 times during the growing season. Under less frequent cutting regime nutritive value of forage is …

The Effect Of N And K Fertilizers On The No3 Content Of Different Grass Species And Mixtures, A Szodfridt, J Varga

IGC Proceedings (1977-2023)

The major quantity of the annual grassland vegetation comes from the first cut in Hungary because of the continental climate of the country. Next to the energy content of grasses it is important to have informations about the amount of some possible toxic components such as nitrate. The critical NO3- value is considered to be 0.25-0.31 % in DM (Andreev, 1981), NO3 content higher than 0.6 % in DM is toxic (Kemp et al., 1977). Ebert et al. (1977) showed that 120 kg/ha N given for the 1st cut did not raise NO3 content higher than the critical value. K …

Determination Of Condensed Tannins In Tropical Legume Forages, L Telek

IGC Proceedings (1977-2023)

The effect of condensed tannins (proanthocyanidins) in ruminant nutrition is complex and needs further interdiscipli­nary reinvestigations with improved analytical methods. With the « cell rupture » theory of legume pasture bloat (Howarth et al., 1978), the role of condensed tannins seems to be secondary; they are acting as protein precipitants (Goplen et al., 1980) and inhibiting microbiological proliferation in cell­ular spaces (Howarth et al., 1982). Their assumed interference with digesting enzymes in vivo is doubtful (Mole and Water­man, 1985). On the importance of condensed tannins in nutrition, several reviews were published (McLeod, 1974; Tempel, 1982; Kumar and Singh, 1984 and …

Screening Sericea Lespedeza Germplasm For Tannin Concentration In The Leaves And Herbage Palatability, J C. Petersen, J A. Mosjidis, N S. Hill

IGC Proceedings (1977-2023)

Several million hectares in the subtropical world are currently used as grazing land for beef and dairy cattle, how­ever, in many cases animal production is very low. To improve animal nutrition, cultivated legume species can be introduced. Sericea lespedeza has potential and could be utilized in the acid soils of the· subtropics. Generally, sericea is low in palatability and nutritive value because its leaves contain tannins, which have long been associ­ated with low intake and reduced digestibility. Tannins are responsible for an astringent or bitter taste caused by the pre­cipitation of salivary glycoprotein (Goldstein and Swain, 1963). Chopping or macerating …

The Effect Of Selenium Fertilizer On The Selenium Status Of Sheep Grazing Annual Pasture In South-Western Australia, B R. Whelan, D W. Peter, N J. Barrow, D J. Buscall, V C. Cox

IGC Proceedings (1977-2023)

White muscle disease was first reported in grazing livestock in Western Australia by Gardiner (1961). Sheep affected by the disease could be divided into two categories : young suckling lambs in winter and early spring, and weaners and hoggets in summer (Gardiner et al., 1962). Subsequent investigations showed that, while there were few clinical symptoms of sel­enium deficiency, there were probably many sheep suffering from ill-thrift. This sub-clinical deficiency caused reduced liveweight gains, reduced wool production and lowered ewe fertility. It was most noticeable in areas of greater than 600 mm of annual rainfall on the lighter sandy soils with …

Synthesis Of Cell Wall Components In Maize Internodes, J H. Cherney, J J. Volenec, G A. Brown

IGC Proceedings (1977-2023)

Cell wall structure affects intake and digestibility of forages by rummants. Before microbial degradation of cell walls can be understood, it will be necessary to have a better understanding of cell wall formation. Internodes of grasses elongate in a_cropetal succession, with two internodes usually elongating s1multaneously. Elongating internodes consist of three regions : 1) a zone of cell division, 2) a zone of cell elongation, and 3) a zone of secondary cell wall deposition. This tissue provides an excellent system for studying cell wall changes in rapidly developing tissues. Our objectives were to : 1) examine changes in cell wall …

Natural And Artificial Drying Effects On Condensed Tannins Of Sericea Lespedeza, T H. University Of Georgia, W R. Windham, J J. Evans, C S. Hoveland

IGC Proceedings (1977-2023)

Sericea lespedeza [Lespedeza cuneata (Dumont-Cours.) G. Don.] is well adapted to acid soils and low fertility but has generally been considered a low-quality forage due to high levels of tannin and indigestible fiber. Tannin levels increase during midsummer (Windham et al. 1988). The most com­monly used assay for tannin in sericea is the vanillin-HCl pro­cedure (Burns, 1963) on oven-dried samples. Oven-drying has been reported to cause increased polymerization or oxidative changes in tannins (Goldstein and Swain, 1963). Fresh-frozen sericea contained higher amounts of extract­able tannin than field-dried forage and fiber digestibility of high-tannin sericea by sheep was much lower …

Improved Management Strategies For Botrytis Fruit Rot, Macrophomina Root Rot, And Verticillium Wilt In California Strawberry Production, Joseph A. Ramirez

Master's Theses

Strawberry production in California is limited by plant diseases such as Macrophomina root rot (MRR) caused by Macrophomina phaseolina, Verticillium wilt (VW) caused by Verticillium dahliae, and Botrytis fruit rot (BFR) caused by Botrytis cinerea. Current disease management strategies are compromised due to fumigant regulations or ineffective disease management practices. This thesis investigated methods to potentially improve the management of these three diseases. Two host plant resistance evaluations for MRR and VW were conducted for the 2022-2023 and 2023-2024 growing seasons. Sixty-three strawberry genotypes were screened in both years. All plants were exposed to the pathogen via artificial …

Maximizing Crop Production And Profitability Through Double Cropping Corn And Soybean Systems In South Carolina, Bennett Harrelson

All Dissertations

Profitability is critical for farm sustainability, efficiency, and longevity. Over the last decade, corn and soybean commodity prices have fluctuated considerably, and more recently, extreme increases in input prices have narrowed profit margins. Non-traditional cropping systems that can boost profit are becoming of interest to farmers in South Carolina, specifically double cropping soybean behind corn. In this scenario, corn is harvested at high moisture contents and followed by ultra-late planted soybean. However, prior research related to the agronomic production practices of double cropping corn and soybean is minimal. To develop best management practices for growers interested in double cropping corn …

Mechanisms Of Perennial Sorghum Resistance To Sugarcane Aphid Infestation, Esha Kaler

Department of Entomology: Dissertations, Theses, and Student Research

Sorghum, Sorghum bicolor (L.) Moench, the fifth most-grown cereal crop in the world, is a versatile crop, grown across different agro-ecological regions. Sorghum has numerous uses ranging from food and forage purposes to biofuel production. Sugarcane aphid (SCA; Melanaphis sacchari) is a major threat to sorghum production, accounting for 50% to 100% yield loss under heavy infestations. Perennial sorghum can be a sustainable and climate-resilient alternative to the current cereal farming systems. The development of perennial sorghum offers numerous benefits, such as reduced economic inputs, more carbon sequestration, better soil health, and sustainable yields. We employed host plant resistance …

Integrating Genomic And Phenomic Breeding Tools For Wheat Stem Sawfly Resistance In Hard Winter Wheat, Sydney E. Graham

Dissertations and Doctoral Documents, University of Nebraska-Lincoln, 2023–

The wheat stem sawfly (WSS; Cephus cinctus) is an insect pest that affects wheat (Triticum aestivum) in the Northern Great Plains. This pest causes stem cutting that makes the plants susceptible to lodging and results in up to 30% yield loss. The primary management strategy for producers is utilizing host plant resistance, for which the main trait is stem solidness. This trait increases the pith thickness and provides resistance to the WSS by increasing larval mortality and reducing stem cutting. While stem solidness is largely controlled by a known major gene (SSt1), the phenotypic expression is also …