Relationships Between The Nutrient Content Of Irrigated Pasture On Offer And That Selected By Grazing Dairy Cows,
2024
Institute of Sustainable Irrigated Agriculture, Australia
Relationships Between The Nutrient Content Of Irrigated Pasture On Offer And That Selected By Grazing Dairy Cows, W J. Wales, C R. Stockdale, P T. Doyle
IGC Proceedings (1997-2023)
An experiment was conducted to determine the dry matter, energy, crude protein and fibre intake by dairy cows in late lactation when grazing perennial pasture offered at allocations of 15, 20, 30 and 40 kg DM/cow.day. The cows consistently selected a diet 10% higher in digestibility than that on offer. In contrast, cows selected diets with crude protein levels increasing from 22% to 40%, above that in pasture on offer, as pasture allocation increased. A similar pattern was observed for the intake of white clover (Trifolium repens L). The increase in the concentration of crude protein in the diet …
Species Preference Influences On Cattle Grazing Behaviour,
2024
AgResearch Grasslands, New Zealand
Species Preference Influences On Cattle Grazing Behaviour, G P. Cosgrove, C B. Anderson, R H. Fletcher
IGC Proceedings (1997-2023)
Lotus corniculatus offers specific nutritional benefits to animals, but exploiting these advantages in grazing systems depends on the proportion of lotus in the feed offered and the animals' preference, hence desire to select for it. To determine preference for lotus, heifers were offered free-choice in contrasting, spatially separated but adjacent monocultures of ryegrass-lotus or red clover-lotus. Following a one-week period to adjust to the species offered and their arrangement, 10 young heifers were observed at 10-minute intervals during daylight hours, and the species they were on and whether or not they were grazing was recorded. This procedure was conducted in …
Partial Preference Of Grazing Cattle For Contrasting Legume Swards,
2024
Massey University
Partial Preference Of Grazing Cattle For Contrasting Legume Swards, C.H. E.C. Poli, J Hodgson, G P. Cosgrove, G C. Arnold
IGC Proceedings (1997-2023)
Yearling heifers in groups of 3 grazed 405 m2 plots made up of alternating 2.4m wide strips of white clover/birdsfoot trefoil (WC+BT) or red clover (RC) in the proportions of 80:20, 67:33, 33:67 and 20:80 for periods of 3 days over four replicates in time, balanced for effects of previous treatment. Observation of the distribution of grazing activity and biting rate were made over 3 hour periods each evening. Biting rates were consistently higher on (WC+BT) than RC (52.3 vs 46.3 ± 0.59 bites.min-1 P(0.0001). Animals initially showed partial preference for the minor sward component in each treatment but regression …
The Use Of Vibration Analysis And Telemetry To Measure Bite Frequency And Intensity In Free-Ranging Horned Ruminants,
2024
University of Hohenheim
The Use Of Vibration Analysis And Telemetry To Measure Bite Frequency And Intensity In Free-Ranging Horned Ruminants, P R. Lawrence, K Becker
IGC Proceedings (1997-2023)
An apparatus is described which detects and measures the vibrations in a ruminant’s horn especially those produced by the animal’s teeth. Vibrations are transmitted by radio to a portable computer where those produced as a result of eating and ruminating can be characterised by their intensity, length and frequency.
Influence Of Vegetation Patch Characteristics On Discriminatory Grazing By Dairy Cows,
2024
Massey University
Influence Of Vegetation Patch Characteristics On Discriminatory Grazing By Dairy Cows, W M. Griffiths, J Hodgson, G C. Arnold, C W. Homes
IGC Proceedings (1997-2023)
Two studies involving the sequential grazing of sets of patches on a perennial ryegrass (Lolium perenne) sward were carried out to investigate the effects of patch characteristics on the selective behaviour of grazing cattle. Experiment 1 involved a range of combinations of sward height (8.9 - 19.6 cm) and bulk density (1.33 - 1.67 mg DM/cm3). Distribution of grazing activity (number of bites or residence time) was strongly and positively related to patch height, but additional effects of variation in bulk density were limited. In Experiment 2 patches were manipulated to offer contrasts in both height (13.4 and …
Shade For Cattle On Pasture: A Guide For Ontario Producers,
2024
University of Guelph
Shade For Cattle On Pasture: A Guide For Ontario Producers, E J. Finegan, T M. Widowski
IGC Proceedings (1997-2023)
In tropical climates, adequate shade may be essential to ensure the survival and productivity of grazing animals, but in the temperate Ontario climate, the necessity or benefits of providing shade for grazing cattle are less clear, and have proved controversial. Meteorological data indicate that beef cattle in Ontario may be at risk of suffering from heat stress on more than 25% of days during July and August, and may decrease feed intake and benefit from the provision of shade for more than 50% of days during the two hottest summer months. A booklet, entitled ‘Beat the Heat. A Guide …
Modelling The "Bottom-Up" Development Pattern Of Tar Spot Disease In Corn,
2024
Purdue University
Modelling The "Bottom-Up" Development Pattern Of Tar Spot Disease In Corn, Brenden Lane, Joaquín Guillermo Ramírez-Gil, Carlos Góngora-Canul, Mariela Sofia Fernandez Campos, Andres Cruz-Sancan, Fidel E. Jiménez-Beitia, Alex G. Acosta-Guatemal, Wily Sic, C. D. Cruz
Graduate Industrial Research Symposium
In 2015, the corn-infecting pathogen Phyllachora maydis (causal agent of tar spot disease) was reported for the first time in the United States. The disease has since spread across the US, causing major yield losses. In 2021 alone, 5.88 million metric tons (231.3 million bushels) of US corn yield were lost to this disease, costing an estimated US$1.25 billion. Though fungicides can protect against these agroeconomic losses, application timing can be difficult to optimize because our understanding of tar spot dynamics is still evolving. The current view is that tar spot typically develops bottom-up through a repeating infection cycle. Because …
Identification Of Alfalfa Chromosomes Using Giemas Banding And Image Analysis Techniques,
2024
USDA, Agricultural Research Service
Identification Of Alfalfa Chromosomes Using Giemas Banding And Image Analysis Techniques, G R. Bauchan, M A. Hossain
IGC Proceedings (1997-2023)
Chromosomes of two diploid (2n=2x=16) subspecies of Medicago sativa, ssp. caerulea and ssp. falcata, their hybrid and tetraploid (2n=4x=32) cultivated alfalfa (M. sativa, ssp. sativa) were studied. Feulgen’s staining, C- and N-banding techniques and an image analysis system were used. The chromosomes of ssp. falcata have only centromeric bands, however, a multitude of bands were observed in both the C- and N-banding pattern of ssp. caerulea and ssp. sativa enabling the precise identification of each of the eight sets of chromosomes and development of a karyotype. The differences in banding patterns between the diploid subspecies makes it possible …
Advances In Breeding Apomictic Brachiaria In Tropical America,
2024
CIAT, Colombia
Advances In Breeding Apomictic Brachiaria In Tropical America, J W. Miles, C B. Do Valle
IGC Proceedings (1997-2023)
Prior to 1988 Brachiaria improvement was based exclusively on the collection, introduction, and evaluation of natural germplasm from Africa. Breeding programs in Brachiaria have been possible only in the past 10 years with the creation of a sexual, tetraploid B. ruziziensis cross-compatible with B. decumbens and B. brizantha. Applied Brachiaria breeding projects are underway both in Colombia (International Center for Tropical Agriculture, CIAT) and Brazil (National Centre for Beef Cattle Research - Brazilian Corporation for Agricultural Research, CNPGC/EMBRAPA). These seek to combine the broad edaphic adaptation and other desirable agronomic attributes of B. decumbens cv. Basilisk with spittlebug resistance. An …
Evaluating Cultivars Of Subterranean Clover In Monoculture Or With Perennial Ryegrass,
2024
Agriculture Victoria, Australia
Evaluating Cultivars Of Subterranean Clover In Monoculture Or With Perennial Ryegrass, K F.M. Reed, S G. Clark, W M. Feely
IGC Proceedings (1997-2023)
Over four years, sowing perennial ryegrass (Lolium perenne) with a range of subterranean clover (“sub clover”, Trifolium subterraneum) cultivars was found to reduce the yield of clover per se by 31% and increase pasture yield by 11%. For one high-producing experimental variety, the presence of grass did not reduce clover yield (P<0.001). Clover yield in monoculture plots was poorly correlated with that measured in mixed swards (r = 0.44), but clover yield (± grass) was correlated with total herbage yield (r = 0.94). Clover seed yield was not reduced by the presence of grass. However, in year 2 - but not in the establishment year - grass reduced seed weight. Irrespective of grass treatment, the new late maturing cultivar, Leura outyielded the other commercial cultivars (P<0.05). Enfield and Enfield x Daliak crosses set the most seed and regenerated with a greater density than other cultivars (P<0.05) - apart from Leura. It was concluded that the winter-active, late maturing cultivar, Leura, will compete most successfully with perennial ryegrass.
Gene Flow In Medicago Through Somatic Hybridization,
2024
Istituto di Ricerche sul Miglioramento Genetico delle Piante Foraggere
Gene Flow In Medicago Through Somatic Hybridization, S Arcioni, F Crea, O Calderini, F Damiani, P D. Cluster, F Pupilli
IGC Proceedings (1997-2023)
The objective of this research was the characterization at both molecular and phenotypic level of three somatic hybrid plants obtained by electrofusion of protoplasts of Medicago sativa with those of M.coerulea, M.falcata and M.arborea, three Medicago species in a different relation with alfalfa. Different kinds of rearrangements including the amplification of new spacer-length variants were detected at rDNA loci in the somatic hybrids. Analysis of field performances confirmed the suitability of these plants for breeding purposes.
Ssr- And Rapd Analysis Of A New Agropyron Repens Genotype,
2024
Agricultural University, Hungary, Purdue University
Ssr- And Rapd Analysis Of A New Agropyron Repens Genotype, G Gyulai, H Ohm, I Dweikat, E Kiss, H Sharma, J Janovszky, L Heszky
IGC Proceedings (1997-2023)
SSR-(single sequence repeat), and RAPD (randomly amplified polymorphic DNA) primer generated DNA fingerprints were used to distinguish a new genotype of quackgrass from its original type of Agropyron repenes L. Beauv. (= Elytrigia repens). Products of polymerase chain reactions (PCR) were separated by agarose (AGE) and denaturing gradient gel electrophoresis (DGGE). Although, both kinds of primers were found to be polymorphic, the microsatellite primer with sequence of 5í-AC(GACA)4-3í generated distinguishing fingerprints in the two types of quackgrasses. This result gives genetic evidence for the new genotype of quackgrass.
Screening Ryegrass Cultivars For Aluminium Sensitivity In Nutrient Soluations,
2024
Department de Ciencias Quimicas
Screening Ryegrass Cultivars For Aluminium Sensitivity In Nutrient Soluations, F O. Gallardo, S Benavides, R Demanet, F Borie
IGC Proceedings (1997-2023)
The objective of this study was to evaluate Al and H+ tolerance of nine ryegrass (Lolium perenne and L. multiflorum) cultivars by growing plants in a mineral solution (pH 4.8 and 6.0 and 0-200 (M Al). Results showed that Yatsyn-1, with a relative root length of 91 was the cultivar least affected by acidity (H+), and Concord ( RRLpH = 58) was the cultivar with the highest H+ sensitivity. In connection with Al-tolerance, Yatsyn-1 and Concord, were the most tolerant cultivars with 88 and 87 RRLAl, respectively whereas Nui and Marathon, were the most sensitive ones, reaching only …
Breeding For Persistence In Lotus Corniculatus,
2024
INIA La Estanzuela, Uruguay
Breeding For Persistence In Lotus Corniculatus, M Rebuffo, N Altier
IGC Proceedings (1997-2023)
The objectives of this study were to develop a more persistent germplasm of birdsfoot trefoil (Lotus corniculatus L.) and to evaluate its potential use in Uruguay. Two cycles of phenotypic recurrent selection were done under field conditions. Eight hundred and 1600 spaced plants were established for the first and second cycle of selection. Both nurseries were visually assessed for crown rot, relative growth, plant habit and foliar diseases. The final selection of the breeding population LE 65-56 includes thirty six plants selected from sixteen elite families. This selection was more persistent and productive than the check varieties in plot …
Apomixis And The Reproductive Dynamics Of Eastern Gamagrass Tripsacum Dactyloides L.,
2024
USDA, Agricultural Research Service
Apomixis And The Reproductive Dynamics Of Eastern Gamagrass Tripsacum Dactyloides L., B Kindiger, C L. Dewald
IGC Proceedings (1997-2023)
Studies were conducted to determine the reproductive characteristics of Tripsacum, a perennial, native pasture species and to identify methods for breeding agronomically superior cultivars. Reproductive methods and types of individuals generated were evaluated with triploid and hexaploids possessing a novel method for transferring sexual germplasm into apomictic tetraploids and tetraploid germplasm into sexual diploids. Triploids and hexaploids are demonstrated to be useful materials for introgressing and transferring desirable alleles across ploidy levels and reproductive barriers.
Cytogenetical Studies In Range Grasses Of Iran,
2024
University of Shahid Beheshti
Cytogenetical Studies In Range Grasses Of Iran, M Sheidai, A Tavasoli, P Derakhshandeh
IGC Proceedings (1997-2023)
Cytogenetical and breeding studies of range grasses are in hand. Present article describes preliminary cytogenetical analysis of wheatgrass (Agropyron) and bromegrass (Bromus) taxa (Agropyron trichophorum n = 21, A. pectinoforome n = 21), two different populations of A. repens (n = 28) and Bromus stenostachyus (n = 14). The species varied with regard to chiasma number and distribution. The highest value occurred in A. repens (Mako population). Heterogenity test for the paired samples showed lack of heterogenity for chiasmata indicating homogenity of Agropyron taxa. However a test for ring and rod bivalents showed significant differences …
Direct Selection Response For Stem Rust Resistance In Tall Fescue,
2024
Oregon State University
Direct Selection Response For Stem Rust Resistance In Tall Fescue, R E. Barker, R E. Welty
IGC Proceedings (1997-2023)
Resistance to stem rust (caused by Puccinia graminis Pers.: Pers. subsp. graminicola Z. Urban.) would be beneficial in tall fescue (Festuca arundinacea Schreb.). Two cycles of polycross (PX) selection on progenies from thirty-four parent plants (14 forage-types and 20 turf-types) were compared to one cycle of open pollination (OP) followed by one cycle of PX selection using a 2-stage greenhouse screening process. Response from selection was determined from composite half-sib progenies from each cycle. Number of plants with resistant reaction based on pustule type increased from 5 to 54% in the PX forage-type population and from 6 to 50% …
Assessment Of Grazing Procedures In The Evaluation Of Plant Breeding Material,
2024
Pasture Research Programme, INIA, Uruguay
Assessment Of Grazing Procedures In The Evaluation Of Plant Breeding Material, D Real, I L. Gordon, J Hodgson
IGC Proceedings (1997-2023)
Four stocking densities (2, 3, 5 and 9 sheep/18 m2 for one hour) and two times of grazing (morning or evening) were imposed on a spaced plant nursery of nine red clover (Trifolium pratense L.) populations of varying growth habit, in order to optimize measurement of sheep grazing preference. Plant height, spread and leafiness were measured before and after each of three grazings. Sheep preference was viewed multivariately, using combined measurements of these plant characteristics. MANOVA revealed that the effect of stocking density was significant (P-0.05), but that of time of grazing was not. The plant, population and overall …
Developing Well Adapted Early To Midseason Cultivars Of Trifoiloum Subterraneum Ssp. Brachycalycinum,
2024
South Australian Research Development Institute (SARDI)
Developing Well Adapted Early To Midseason Cultivars Of Trifoiloum Subterraneum Ssp. Brachycalycinum, C T. De Koning, P G.H. Nichols, R L. Tuckwell, N Schubert
IGC Proceedings (1997-2023)
Development and selection of early to midseason cultivars of subterranean clover (Trifolium subterraneum L.) ssp. brachycalycinum has mostly involved the use of early generation selection nursery swards (F2-progeny method). Four sites were sown in the mid-North region of South Australia. At the end of 1995, the top 20 lines from each site had burrs (seed pods) sampled at random. The burr will proceed into the final early generation selection phase (1 - 2 years). Dependent on the site, many lines have out-performed the standard checkplot cultivar, Clare. High hardseed levels have also been incorporated into 1989 crossbreds.
Regeneration Of Somatic Hybrids Between Festuca Arundinacea Var. Glacescens And Lolium Multiflorum Lam.,
2024
Forage Crop Breeding and Seed Research Institute, Japan
Regeneration Of Somatic Hybrids Between Festuca Arundinacea Var. Glacescens And Lolium Multiflorum Lam., T Sasaki, T Hasegawa, S Ueda
IGC Proceedings (1997-2023)
Protoplasts derived from ten suspension cultures of tetraploid Festuca arundinacea var. glaucescens (2n = 4x = 28) and diploid Lolium multiflorum Lam. (2n = 2x =14) were fused to produce somatic hybrids. Regenerated green plants in three fusion combinations were identified as somatic hybrids because they showed characters that were peculiar to both Festuca arundinacea var. glaucescens (hairs on auricle) and Lolium multiflorum Lam. (root-fluorescence). Moreover, the hybrids also had a chromosome number of about forty two.
