Effect Of Tiller Endophyte Infection Frequency And Nitrogen Fertilizer Rate Of Tall Fescue On Steer Performance Over Nine Seasons Of Grazing,
2024
USDA, Agricultural Research Service
Effect Of Tiller Endophyte Infection Frequency And Nitrogen Fertilizer Rate Of Tall Fescue On Steer Performance Over Nine Seasons Of Grazing, J A. Stuedemann, S R. Wilkinson, D P. Belesky, F N. Thompson, D L. Breedlove, D M. Hildreth, H Ciordia, A H. Parks, C S. Hoveland, J Huang
IGC Proceedings (1977-2023)
Acremonium coenopliialium-infected tall fescue (Festuca arrundinacea Schreb.) is associated with animal health problems including reduced ,veight gains. Twelve 0.7 ha paddocks were used to study Kentucky- 31 tall fescue at low (LE=25%) or high (HE::58%) tiller endophyte (E) infection frequencies and fertilised with either 134 (LN) or 336, kg nitrogen/ha/year (HN) in a 22 factorial arrangement of treatments. Yearling Angus steers grazed under put-and-take management from April or May through late July or early August in each of nine years. In all except one year, ADG was lower (P<0.0769 to P<0.0018) on HE than LE. In 4 of 9 years, HN lowered (P<0.0821 to P<0.0003) ADG compared to LN. In only 2 of 9 years was there an NxE interaction (P<0,0537), the interactions expressing opposite effects when comparing the 2 years. In all but 3 years there was a linear (P<0.0606 to P<0.0019) relationship between endophyte infection rate and ADG. In only 1 of 9 years were quadratic effects significant (P<0.0407). Endophyte infestation consistently lowered steer AOG in a linear fashion with N effects less distinct,
Variation In The Isoflavone And Pterocarpan Contents Of Red Clover,
2024
Agricultural Research Centre of Finland
Variation In The Isoflavone And Pterocarpan Contents Of Red Clover, T Mela, J Laakso, T Maenpaa, H Ihamaki
IGC Proceedings (1977-2023)
Variations in isoflavone and pterocarpan contents were studied in cloned material of red clover (Trifolium pratense L,), The most abundant constituents in the leaves, as determined by gas chromatography, were formononetin (50%) and biochanin A (25%), whereas the rools were characterised by the pterocarpan manckiain (45%). The amounts of leaf isoflavones (range 100-880 µg/100 mg DM) differed significantly between clones at subsequent growth stages, and considerably lower levels were found when compared with the control material. The contents were highest in the beginning of the growing season (June), but decreased strongly towards the end of the lowering period. The …
Variability Of Oestrogen Content In Large Collections Of Subterranean Clover And Its Implications For Selection,
2024
Instituto Sperimentale per le Colture Foraggere
Variability Of Oestrogen Content In Large Collections Of Subterranean Clover And Its Implications For Selection, Efisio Piano, A Tava, F Spanu, L Pecetti
IGC Proceedings (1977-2023)
Large collections of subterranean clover lines were evaluated for the content of oestrogenic isoflavones formononetin, genistcin and biochanin A. Differences among the species Trifolium brachyalycinum, T. subterraneum and T. yanninuicum were determined mostly by differences in the content of individual isoflavone components rather than in total isoflavone content. The concentration of the most biologically active isoflavone formononetin was highest in T. yaminicum and lowest in T. brachycalycinum. There was extreme variation among lines for isoflavone contents. The variance among populations (means of lines from the same collection site) wns significant in all species, suggesting some influence of the environment …
Integration Of High Formononetin Red Clover In Sheep Grazing Systems,
2024
AgResearch, NZ
Integration Of High Formononetin Red Clover In Sheep Grazing Systems, G S. Baxter, D R. Stevens, A J. Harris
IGC Proceedings (1977-2023)
Pasture and animal production from pastures based on perennial ryegrass (Lolium perenne L.) with either white clover (Trifolium repens L.), red clover (Trifolium pratense L.), or a dual clover base having 60% of the area in white clover and 40% in red clover, were compared over 3 years in self-contained I ha farmlets stocked with 20 ewes/ha, Annual pasture production was similar on all three farmlets, although autumn production of the red clover farmlet was significantly lower than the white or mixed clover systems. Legume production was greatest on the mixed and red clover farmlets in summer and the …
Drought Pearl Millet- An Unpalatable Enigma,
2024
Cunningham Laboratory
Drought Pearl Millet- An Unpalatable Enigma, D J. Minson, J B. Hacker, M Shimojo, P Stuart, J Slatter
IGC Proceedings (1977-2023)
After planting in late 1989 there were many reports that Nutrifeed was unpalatable to cattle, sheep and horses. Seventyfive properties were visited where unpalatability was common, a questionnaire was distributed and samples of forage and soil were analysed. Forty-six properties reported unpalatability but on the other 29, pearl millet was palatable. Unpalatability developed only when forage grown on soil high in available nitrogen was subjected to a shortage of water. Unpalatable forage was dark green, contained more than 3S g N/kg DM and was often low in phosphorus, After rain or irrigation the new growth was usually palatable but stock …
Accumulation Of Pyrrolizidine Alkaloids During Growth Of Tall Fescue,
2024
University of Kentucky
Accumulation Of Pyrrolizidine Alkaloids During Growth Of Tall Fescue, Lowell Bush, Scott Gay, Walyati Burhan
IGC Proceedings (1977-2023)
The experiments were initiated to determine the association between growth of the fungal endophyte Acremoium coenophliaum and the accumulation of pyrrolizidine alkaloids (PA) and to measure the influence of A. coenophialum on water use and photosynthesis by tall fescue (Festuca arundinacea Schreb.). PA concentration increased with growth after seeding. First and second regrowth tissues contained higher levels of PA than first harvest tissue of the same age. Endophyte content in the pseudostems increased until 11 weeks after seeding and then decreased. Pseudostems of each subsequent regrowth period contained less endophyte. During a soil drying cycle 'l'w was …
Steer Performance From Tall Fescue Pastures With Three Levels Of Acremonium Coenophialum Infestation,
2024
University of Tennessee, Knoxville
Steer Performance From Tall Fescue Pastures With Three Levels Of Acremonium Coenophialum Infestation, J C. Waller, H A. Fribourg, R W. Thompson, A B. Chestnut
IGC Proceedings (1977-2023)
Two replications of 1.2-ha pastures were seeded in 20-cm drill rows to 3 treatments: endophyte-free (E-) tall fescue (Festuca arundinacea); tall fescue infested at 80% (E+) with Acremonium cenophialum; a mixed sward of alternate sets of 4 drill rows of E+ and E- tall fescue (E+/E-). Stand density and endophyte levels were monitored every 6 months, remaining at original levels throughout the study. Each pasture had 3 test steers (Bos taurus) with extra steers used as needed to maintain forage height 2.5-7.5 cm. Average daily gain (ADG) ranged from about 300 to over 700 g/day …
Coping With Mycotoxins That Constrain Animal Production,
2024
AgResearch, NZ
Coping With Mycotoxins That Constrain Animal Production, N R. Towers, M R. Siegel
IGC Proceedings (1977-2023)
Many fungi are parasites and saprophytes of growing and conserved forage crops. A number of these produce mycoloxins, the synthesis of which is controlled by the interaction of fungal and host genomes and the environment. Mycotoxins have diverse chemical structures and elicit a range of responses in ruminant animals. Some of the more important mycotoxin-producing fungi found in forages include Claviceps spp. (ergot alkaloids, paspalitrems) and Acremonium spp. (ergot alkaloids, lolitrcms) causing various forms of ergot toxicity and neurological (lremorgenic) disorders; Pithomyces clrartarum (sporidesmin) and other fungal species causing photosensitisation (e.g., facial eczema, geeldikkop); Phomopsis /eptoslromiformis (phomopsins) causing lupinosis; Rhizoctonia …
Recent Developments In Higher Plant Toxin Research Of Relevance To Animal Production,
2024
The University of Queensland, Australia
Recent Developments In Higher Plant Toxin Research Of Relevance To Animal Production, A A. Seawright, M P. Hegarty
IGC Proceedings (1977-2023)
Advances have been achieved in the diagnosis of chronic intoxications caused by poisonous plants in which the pathological changes present In the affected animals are not definitive, by the chemical identification of toxin adducts in their tissues. This has been demonstrated for pyrrolizidine alkaloids which are of global significance as plant poisons and has resulted on occasion in more determined efforts in eliminating the plants responsible. Many plant toxins need to be metabolised for toxicity within the animal's tissues in order to result in disease, and the furanoterpenes found mainly in myoporaceous plants are e,rnmples, Dietary regimes that lend lo …
Invertebrate Pests, Plant Pathogens And Beneficial Organisms Of Improved Temperate Pastures,
2024
New Zealand Pastoral Agricultural Institute
Invertebrate Pests, Plant Pathogens And Beneficial Organisms Of Improved Temperate Pastures, R P. Pottinger, M J. Barbeiti, T J. Ridsdill-Smith
IGC Proceedings (1977-2023)
The role of pests, pathogens and beneficial organisms in temperate pasture and animal production is highlighted. Significant differences between pests and. the severity of their infestations exists between the Northern and Southern Hemispheres, because both pasture and pest species and their natural enemies have been carried by colonists to the New World countries in the Southern Hemisphere, Pests and pathogens place significant constraints on the sustainability and productivity of pastoral agriculture. Acquisition of basic databases and development of a wider range of controls has occurred over the past 25 years, but the effort has been disjointed. Knowledge of the more …
Invertebrate Pests, Plant Pathogens, And Beneficial Organisms In Extensive Natural Grassland,
2024
New Mexico State University
Invertebrate Pests, Plant Pathogens, And Beneficial Organisms In Extensive Natural Grassland, J G. Watts, L W. Burgess, E W. Huddleston
IGC Proceedings (1977-2023)
After many decades of research on their control, insects and weeds still arc a major factor in semi-arid grassland ranching. Much has been learned concerning their biology, habits and chemical control but penetrating study of the microbial world surrounding them is quite recent. Plant pathogens are credited with little damage to semiarid grasslands. Potentially, their most important role may be one of toxigensis among grazing animals after unusual weather that promotes exceptional increase of any one or a combination of several indigenous toxigenic fungi on senescing grasses. Objective cost-benefit consideration of pest and disease control was limited in past decades …
Resistance Versus Susceptibility To Verticillium Albo-Atrum In Alfalfa,
2024
The Pennsylvania State University
Resistance Versus Susceptibility To Verticillium Albo-Atrum In Alfalfa, B W. Pennypacker, K T. Leath, D P. Knievel, E J. Pell
IGC Proceedings (1977-2023)
Alfalfn (Medicago saliva L.) clones, susceptible and resistant to Verticillium albo-atrum (Van), were systematically infected with Vaa via stubble inoculation with conidial suspensions. Progress of infection and anatomical host responses was monitored by sequential sampling, sectioning, staining and examination with light microscopy. Effect of infection on photosynthesis was assessed in vivo by measuring net photosynthesis and activity of ribulose 1, 5-biphosphate carboxylaseoxygenase (rubisco) via a CO2 drawdown curve. hr vitro activity of rubisco was determined by protein extraction and uptake of radioactive CO2. Susceptible and resistant clones exhibited leaflet chlorosis and abscission. Also, the pathogen produced spores that germinated …
Breeding For Multiple Pest Resistance As A Strategy To Improve White Clover Persistence,
2024
USDA, Agricultural Research Service
Breeding For Multiple Pest Resistance As A Strategy To Improve White Clover Persistence, G A. Pederson, G L. Windham, M R. Mclaughlin, R G. Pratt, G E. Brink
IGC Proceedings (1977-2023)
White clover (Trifolium repens L.) cultivars grown in the USA are susceptible to many pathogens, pests and environmental stresses which have been shown to affect persistence adversely. The strategy used in our breeding programme is to first develop white clover populations resistant to individual pathogens and pests, and then incorporate this resistance into multiple-pest-resistant populations. Germplasms with resistance to peanut stunt virus (PSV), alfalfa mosaic virus (AMY), and clover yellow vein virus (CYVV), and with drought tolerance have been released. From these germplasms and other source materials, we have developed additional populations with resistance to southern root-knot nematode ( …
Clover Cyst Nematode Resistance In White Clover,
2024
AgResearch, NZ
Clover Cyst Nematode Resistance In White Clover, J Van Bosch, C F. Mercer, J L. Grant, I K. Black
IGC Proceedings (1977-2023)
White clover (Trifolium repens L.), a key legume in New Zealand pastures, is parasitised by Heterodera trifolii, the clover cyst nematode. Resistance breeding is the most feasible control, and screening of 1st generation crosses has made considerable progress. Progeny of parents selected for resistance had only 39% cysts/g root dry weight of susceptible lines, and all resistant lines were lower when ranked. These resistant selections also had less fewer cysts per plant, heavier root dry weights and higher shoot growth scores. The parents of the most resistant lines were from two Italian ladino cultivars (Ladino Gigante Lodigiano and …
Rhoma Black Stem Disease- A Threat To Susceptible Annual Medic Pastures,
2024
Department of Agriculture, AU
Rhoma Black Stem Disease- A Threat To Susceptible Annual Medic Pastures, M J. Barbetti
IGC Proceedings (1977-2023)
Phoma black stem disease, caused by Phoma medicaginis, is the most important fungal disease of annual Medicago spp. (medic) pastures in Western Australia. It is readily seed-borne and this provides an important inoculum source for spreading the disease into new sowings in areas free of leguminous crop residues. The disease produces dark brown to black lesions on cotyledons, leaves, petioles and stems and can cause leaf drop and petiole and stem collapse, Reductions in herbage production of up to 169!, and seed yield of up to 209!, have been recorded in grazed swards, while in ungrued swards, losses in herbage …
Effectiveness Of Acremoniu Lolli In Annual Ryegrass In Controlling Greenbug (Schizaphis Graminum Rondani) Injury,
2024
Texas A&M
Effectiveness Of Acremoniu Lolli In Annual Ryegrass In Controlling Greenbug (Schizaphis Graminum Rondani) Injury, L R. Nelson, Marta R. Harrington, D Marshall
IGC Proceedings (1977-2023)
This experiment tested 3 ryegrass (Lolium multiflorum Lam.) genotypes with (E+ )° and without (E-) endophyte, to determine the effectiveness of the endophyte in reducing leaf damage caused by greenbugs (Schlzaplris granthum Rondani). Results Indicated that presence of endophyte increased resistance in only I of 3 lines tested. The apparent resistance was observed.as leaf necrosis (leaf necking, yellowing, tip die-back, and leaf death). Resistance was not observed until green bug reinfestation of 3-month-old plants. A control with E+ Kentucky 31 fescue (Festuca arundinacea Schreb.) also had reduced greenbug damage compared with E- Kentucky 31 plants. This study …
Invertebrate Pests Of Endophyte-Infected And Endophyte Free Perennial Ryegrass Swards In Northern New Zealand,
2024
AgResearch, NZ
Invertebrate Pests Of Endophyte-Infected And Endophyte Free Perennial Ryegrass Swards In Northern New Zealand, R A. Prestidge, R N. Watson, E R. Thom
IGC Proceedings (1977-2023)
Plots of endophyte-infected and endophyte-free perennial ryegrass (Lollum perenne) cv. Ellett and white clover (Trifolium repens) cv, Grasslands Pitau were established in autumn 1990 by direct drilling into pastures previously sprayed with glyphosate herbicide. Plots were rotationally grazed by dairy cows. Insect pests were sampled by soil coring and extraction, and plant pathogenic nematodes by root staining and examination. Ryegrass tiller density and the proportion of ryegrass in the swards were-significantly less in November, March and May on plots sown with endophyte-free ryegrass c_ompared with endophyte-infected ryegrass. Conversely, the propo!'tion __ of white clover was greater on endophyte-free …
Invertebrate Pests Associated With Italian Ryegrass In Northern New Zealand,
2024
AgResearch, NZ
Invertebrate Pests Associated With Italian Ryegrass In Northern New Zealand, R A. Prestidge, R N. Watson, E R. Thom
IGC Proceedings (1977-2023)
Damage threshold levels were established for adult Argentine stem weevil (Listronotus bonariensis (Kuschel)) feeding on Italian ryegrass (Lolium multiflorum Lam;) cv, Concord seedlings in a glasshouse pot trial. Population densities of 35-70/m1 reduced seedling survival by 34% and herbage yield after 28 days growth by 35%. A field trial was established In autumn 1991 by sowing Concord in early February, in late February and in March into areas previously treated with glyphosate herbicide, Insecticide application increased ryegrass tiller density by 36% from 2339/m' (April 1991) and herbage accumulation by 43% from 1.4 t DM/ha only up to the …
Screening For Biological Control Agents Of Root Pathogens Of Pasture Legumes,
2024
AgResearch, NZ
Screening For Biological Control Agents Of Root Pathogens Of Pasture Legumes, R A. Skipp, F S. Hay
IGC Proceedings (1977-2023)
Fungi isolated from roots of legumes from pasture soil were applied to seeds of red clover (Trifolium pratense L.) on water agar in Petri plates in a seedling screening test designed to detect antagonism to the fungal pathogens Fusarium solani, Trichrocadium basicola and a Pythium sp. Isolates of Triclroderma koningii, T. /ramatum, a binucleate Rhizoc1011ia sp. or an unidentified basidiomycete protected seedling roots from damage by one or more of the fungal pathogens. Fungi isolated from cysts of the plant-parasitic nematode Helerodera trifolii obtained from pasture soil were tested for their ability to infect eggs of H. trifolii …
Effects Of Three Viruses On Productivity Of Annual Pasture Legume Swards,
2024
Department of Agriculture
Effects Of Three Viruses On Productivity Of Annual Pasture Legume Swards, R A. C Jones
IGC Proceedings (1977-2023)
The effects of 3 non-persistently aphid-transmitted viruses on the productivity of swards of annual pasture legumes were investigated in 1988-91. Virus-host combinations studied were alfalfa mosaic virus (AMV) in burr medic (Medicago polymorplia), cucumber mosaic virus (CMV) in subterranean clover (Trifo/i111n subterra11eum) and bean yellow mosaic virus (BYMV) in subterranean clover. Swards were mown to simulate grazing, grazed or left undefoliated. Herbage (dry weight) and seed production were decreased significantly by infection with all three virus-host combinations. However, the extent of losses vnried with extent of virus spread, cultivar, site and season. Decreased seed yield resulted from both fewer and …
