Development and evaluation of grazing-tolerant alfalfa cultivars: A review

2000 ◽  
Vol 80 (3) ◽  
pp. 503-512 ◽  
Author(s):  
S. R. Smith Jr. ◽  
J. H. Bouton ◽  
A. Singh ◽  
W. P. McCaughey
Keyword(s):  
Medicago Sativa ◽  
Selection Procedure ◽  
Standard Test ◽  
Grazing Management ◽  
Management Systems ◽  
Test Protocol ◽  
Grazing Tolerance ◽  
Breeding Populations ◽  
The Usa ◽  
High Yields

Plant breeders have long sought to improve grazing tolerance of alfalfa without sacrificing the beneficial yield and quality attributes of this species. Most efforts have focussed on selecting for traits (e.g., creeping rootedness) related to grazing tolerance and/or simulated grazing, but these efforts failed to account for the multiple stresses caused by grazing animals. Trait selection often led to sacrifices in yield and other desirable characteristics resulting in cultivars that were not robust across grazing management systems and environments. An innovative selection procedure was recently developed at the University of Georgia which incorporated intensive grazing with continuous stocking by beef cattle. The development of "Alfagraze" using this procedure showed that grazing tolerance and high yields can be incorporated into the same cultivar, along with consistent performance across grazing management systems and environments. Subsequent research has shown that grazing tolerance can be improved within elite, high-yielding, multiple-pest-resistant cultivars and breeding populations. Selection using intensive grazing with continuous stocking has been summarised in a "Standard Test Protocol" that is now being successfully used by public and private alfalfa breeders and in cultivar evaluation programs in the USA, Canada, and other countries. Key words: Medicago sativa, Medicago sativa ssp. falcata, persistence, lucerne, grazing tolerance, Alfagraze

The Use of Primary Cultured Rat Hepatocytes for the Assessment of Xenobiotic Effects on Biotransformation

1991 ◽  
Vol 19 (2) ◽  
pp. 209-213
Author(s):  
Gabi Schepers ◽  
Christiane Aschmann ◽  
Sabine Mörchel
Keyword(s):  
Cell Viability ◽  
Rat Hepatocytes ◽  
Standard Test ◽  
In Vitro Test ◽  
Chlorinated Phenols ◽  
Test Protocol ◽  
Primary Cultured Rat Hepatocytes ◽  
Cultured Rat Hepatocytes ◽  
Different Response

An in vitro test protocol is reported, which, using primary cultured rat hepatocytes, allows for the screening of xenobiotic effects on biotransformation as well as on basal cellular functions. O-Deethylation of 7-ethoxycoumarin (7-EC) and subsequent conjugation of the metabolite 7-hydroxycoumarin (7-HC) with sulphate or glucuronic acid are determined, as representative parameters for the hepatic biotransformation. Cell viability is examined by measuring cellular ATP content and leakage of lactate dehydrogenase. With respect to immediate and delayed effects on biotransformation reactions, the standard test protocol includes exposure to xenobiotics for 1, 24 and 48 hours. Different response patterns could be demonstrated for the solvents dimethylformamide (DMF) and dimethylsulphoxide (DMSO), and the chlorinated phenols, pentachlorophenol (PCP) and hexachlorophene (HCP), which are known to uncouple mitochondrial respiration. Short-term incubation with the solvents resulted in decreased 7-EC- O-deethylation without signs of cytotoxicity. PCP and HCP inhibited 7-EC- O-deethylation and 7-HC-conjugation, affecting sulphate and glucuronide formation differently. 24-hour exposures to PCP and HCP resulted in decreased 7-ethoxycoumarin- O-deethylase activity, which correlated with diminished cell viability, while DMSO and DMF enhanced 7-EC- O-deethylation at sub-cytotoxic concentrations. After exposure for 48 hours to the solvents, enzyme induction was even more pronounced.

Dairy farm feeding and income effects of using Voisin grazing management of permanent pastures

1986 ◽  
Vol 1 (4) ◽  
pp. 147-152 ◽  
Author(s):  
William M. Murphy ◽  
John R. Rice ◽  
David T. Dugdale
Keyword(s):  
Dry Matter ◽  
Forage Yield ◽  
Grazing Management ◽  
Operating Costs ◽  
Net Energy ◽  
Net Income ◽  
Forage Crops ◽  
Excellent Quality ◽  
Continuous Grazing ◽  
High Yields

AbstractPermanent pastures produce far below their potential, as they are usually managed in the northcentral and northeastern United States. Dairy farmers in these regions generally feed their cattle year-round from stored forage and purchased concentrates, and use permanent pastures as mere holding or exercise areas, grazing them continuously. This practice involves high operating costs that, combined with lower milk prices, have resulted in greatly reduced profit margins. Farming practices that return more net income are needed. The Voisin system of rotational grazing management, which applies intensive management to forage crops on pastureland, is widely used on dairy and sheep farms in New Zealand. Farmers using the Voisin system there have low operating costs and obtain high yields of excellent quality forage over long grazing periods; increased net income results Between 1 May and 1 October 1984, 497 forage samples were taken and analyzed from permanent pastures grazed according to the Voisin management system on six Vermont dairy farms. This was done to provide farmers with current estimates of forage feeding value so that they could balance their cows' rations accordingly throughout the season, and determine if they could improve the profitability of their farms by using Voisin grazing management. Average grazingseason analyses (dry weight) were: 22.5% dry matter, 22.4% crude protein, 20.8% available protein, 28.4% acid detergent fiber, 1.18% calcium, .48% phosphorus, 1.60% potassium, .22% magnesium, and 1.58 Mcal/kg net energy lactation. Average dry forage yield was 8.9 metric tons/ha. Dry matter intake was adequate for milk production up to 36 kg/cow/day. Forage protein and energy contents were sufficient for at least 25 and 18 kg milk/day, respectively. On three farms where economic factors were calculated, net profits per cow averaged $67 more during the 5-month period from using Voisin grazing management, compared to continuous grazing of the same pastureland in the year before Voisin management was used. This profit resulted mainly from feed savings and a more favorable milk:concentrate ratio of 4.1:1 obtained with Voisin management, compared to 2.7:1 with continuous grazing and more feeding of stored or machine-harvested forage. Voisin-managed pastures can produce high yields of excellent-quality forage that can be incorporated into dairy feeding programs, thereby reducing feed costs and increasing profitability of the farming operations.

Rotational grazing management of forage peanut

2020 ◽  
Vol 56 (4) ◽  
pp. 495-505
Author(s):  
Lucas da Rocha Carvalho ◽  
Lilian Elgalise Techio Pereira ◽  
Sila Carneiro Da Silva
Keyword(s):  
Experimental Period ◽  
Early Spring ◽  
Grazing Management ◽  
Dry Matter Accumulation ◽  
Adaptation Period ◽  
Forage Grasses ◽  
Rotational Grazing ◽  
Area Index ◽  
Grazing Tolerance ◽  
Tropical Forage

AbstractThe perennial forage peanut is a stoloniferous, perennial tropical legume with potential for use in pastures. Based on the hypothesis that under intermittent stocking herbage accumulation would follow a similar pattern to that described for tropical forage grasses, the objective of this study was to evaluate canopy characteristics and herbage accumulation of forage peanut subjected to strategies of rotational grazing management. Treatments corresponded to all possible combinations of two grazing frequencies (regrowth interrupted at 95% and maximum canopy light interception – LI95% and LIMax) and two grazing severities (post-grazing canopy heights (CHs) equivalent to 40 and 60% of the pre-grazing heights). Treatments were imposed to experimental units during an adaptation period (from November 2014 to January 2015) and the subsequent experimental period lasted from February 2015 to April 2016, comprising two consecutive pasture growing seasons with no interruption between them (summer I to summer II). The pre-grazing targets of LI95% and LIMax corresponded to CHs of 13 and 18 cm, respectively. Forage peanut showed high grazing tolerance as pre-grazing leaf area index (except during summer I and autumn/winter), total herbage, and leaflet dry matter accumulation varied only with seasons. Higher rates of herbage production were recorded during summer I and summer II, followed by those during late and early spring and autumn/winter. Since there was no difference in the pattern of herbage accumulation between LI95% and LIMax and stolons predominated at the bottom of the canopies, forage peanut may be rotationally grazed with greater flexibility than most tropical forage grasses. Recommended pre-grazing CHs are within 13 and 18 cm, and post-grazing heights between 40 and 60% of the pre-grazing height.

Preliminary design and testing of neck chamber device for baroreflex sensitivity assessment

2020 ◽  
Vol 6 (4) ◽  
pp. 132-142
Author(s):  
Pratik V Paliwal ◽  
Prathamesh H Kamble ◽  
K A Desai ◽  
Rajesh Sharma ◽  
Anish Singhal
Keyword(s):  
Standard Test ◽  
Design Development ◽  
Test Protocol ◽  
Non Invasive ◽  
Carotid Baroreceptor ◽  
Sensitivity Assessment ◽  
Neck Chamber ◽  
Design And Testing ◽  
Opening Up ◽  
Stimulation Of

This paper presents the design, development and testing of a novel neck chamber device for non-invasive stimulation of an individual carotid baroreceptor in a graded manner. The proposed neck chamber device is a strap-free design that avoids discomfort during testing due to tight seal generated by the neck collar design, and facilitates unilateral testing and targeted assessment without stimulating other neck baroreceptors. The device consists of two independent components to achieve these requirements: an outer suction mechanism and an inner chamber. The outer mechanism consists of multiple suction cups to grip the device over the human neck, while the inner chamber creates controlled positive and negative pressure for stimulation of baroreceptors using a pump. The indigenously developed device was employed for the testing by providing neck chamber stimulation in discrete steps of –20 mm Hg, –40 mm Hg, −60 mm Hg, 0 mm Hg, 20 mm Hg, 40 mm Hg and 60 mm Hg with the gap of 60 s between each stimulation as per the standard test protocol of autonomic function test. The changes in heart rate and RR interval were recorded to determine the baroreceptor gain using the logistic equation derivative and gain curve plot. The results of the present study show that the estimated baroreceptor gain is –0.109±0.04, which is consistent with the previous studies conducted using neck collar devices. The testing results showed that the desired objectives are achieved successfully by the prototype device, opening up the possibility of its use for the treatment of resistant hypertension.

scholarly journals Climate data analysis to assess resilience of wall assemblies to moisture loads arising from the effects of wind-driven rain

2020 ◽  
Vol 172 ◽  
pp. 11003
Author(s):  
Zhe Xiao ◽  
Michael A. Lacasse ◽  
A. Gaur ◽  
Elena Dragomirescu
Keyword(s):  
Geographic Location ◽  
Standard Test ◽  
Future Climate ◽  
Sufficient Information ◽  
Climate Data ◽  
Test Protocol ◽  
Changing Climate ◽  
Expected Performance ◽  
Moisture Performance

In North America, and abroad, there currently exist standard test protocols for assessing the watertightness of wall assemblies and fenestration components although most of these methods are not directly related to expectations of in-field conditions as might be experienced by a wall assembly over its intended service life. How useful might such test protocols be to help determine the longevity of wall assemblies to future climate loads? Existing walls may, depending on their geographic location, be vulnerable to future climate loads and thus risk premature deterioration. For the design of new wall assemblies consideration ought to given to the non-stationarity of the climate and implications on the moisture loads on walls and the expected performance over the long-term. To permit assessing the resilience of wall assemblies to the effects of a changing climate as may occur in the future, and indeed, perhaps heightened moisture loads, one requires sufficient information on the watertightness of the assembly in relation to specified wind-driven rain loads and wall air-leakage conditions from which wall moisture retention functions could readily be developed. Such moisture functions are the basis of input of moisture loads to hygrothermal models and from which the expected long-term wall moisture performance can subsequently be derived. In this paper, a description is provided of the strategies used to analyze the WDR load for generating experimental input for a watertightness test protocol under development to assess resilience of wall assemblies to moisture loads arising from the effects of wind-driven rain in consideration of both historical climate loads and those as may arise from a changing climate.

What explains the recourse of US commercial banks to securitization?

2016 ◽  
Vol 15 (3) ◽  
pp. 317-328 ◽  
Author(s):  
Nesrine Bensalah ◽  
Hassouna Fedhila
Keyword(s):  
Credit Risk ◽  
Selection Procedure ◽  
Regulatory Capital ◽  
Heckman Selection Model ◽  
Mortgage Loans ◽  
Content Type ◽  
Risk Transfer ◽  
Credit Risk Transfer ◽  
The Usa ◽  
Heckman Selection

Purpose The purpose of this paper is to investigate the reasons that urge US banks to securitize. Design/methodology/approach The authors apply a logistic regression model to a sample of 5,394 observations. The dependent variable takes 1 if the bank securitizes and 0 if not. The authors use also, a Heckman selection model to account for the potential dependence between the decision to securitize and the decision of which assets to securitize. Findings The results indicate that liquidity, credit risk transfer, regulatory capital arbitrage and profitability are the most important factors that drive securitization in the USA. Moreover, the nature of the asset securitized appears to be dependent on the objective that the bank pursues. For funding and capital arbitrage objectives, the bank needs to securitize its mortgage loans. However, for credit risk transfer purposes, it has to opt for a non mortgage securitization. The nature of the asset securitized can thus, be used as a signal for bank’s intentions to securitize. Originality/value This study contributes to a better understanding of the reasons that urge banks to securitize. It also presents, using a Heckman selection procedure, a detailed analysis that discriminates between different types of securitization.

Evaluating alfalfa cultivars and germplasms for pastures using the mob-grazing technique

1994 ◽  
Vol 74 (1) ◽  
pp. 109-114 ◽  
Author(s):  
S. Bittman ◽  
D. H. McCartney
Keyword(s):  
Medicago Sativa ◽  
Rest Period ◽  
Grazing Intensity ◽  
Ground Cover ◽  
Smooth Bromegrass ◽  
Grazing Tolerance ◽  
Grazing Intensities ◽  
The Media ◽  
Growth Habits ◽  
Northern Alberta

There is growing evidence that alfalfa (Medicago sativa L. sensu lato) germplasms that perform well in trials that are mechanically clipped may not persist well under grazing. This trial assessed the persistence of nine alfalfa germplasms under grazing over a period of 4 yr in northeast Saskatchewan. The germplasms included registered cultivars and experimental strains of M. sativa ssp. media Pers. and M. sativa ssp. falcata (L.) Arcang. with a range of growth habits and winterhardiness. Each paddock was seeded with all entries in mixture with smooth bromegrass (Bromus inermis Leyss.) and grazed repeatedly for 1- to 2-d periods, using high stocking rates, to ensure that all entries were grazed uniformly. Three grazing intensities — light, moderate and intense — were set by varying the rest period between grazings. Ground cover of all the currently recommended alfalfa cultivars of the media ssp. declined during the trial; the germplasms of falcata ssp. increased; and two media ssp. strains from northern Alberta maintained fairly constant ground cover. Grazing intensity affected rate of stand decline but not final ranking of germplasms, so there was no grazing × germplasm interaction. Seeded and volunteer smooth bromegrass maintained better stands under light than intense grazing, whereas volunteer bluegrass (Poa spp.) performed better under intense grazing. Ground cover of alfalfa germplasms was generally correlated with their annual yield and proportion of total dry matter yield. The results suggest that falcata germplasms should be included in seed mixes for long-term pastures and that mob grazing be used to assess the persistence of alfalfa germplasms before they are recommended for use in pastures. Key words:Medicago sativa L., Medicago sativa ssp. falcata (L.) Arcang., persistence, grazing tolerance.

The competitive and yielding ability of some sub-tropical pasture species sown alone and in mixtures under intermittent grazing at Samford, south-eastern Queensland

1969 ◽  
Vol 9 (37) ◽  
pp. 181 ◽  
Author(s):  
RJ Jones ◽  
Davies J Griffiths ◽  
RB Waite
Keyword(s):  
White Clover ◽  
Competitive Ability ◽  
Grazing Management ◽  
Tropical Pasture ◽  
Weed Species ◽  
Rhodes Grass ◽  
Nitrogen Levels ◽  
Tropical Legumes ◽  
High Yields ◽  
Low Nitrogen

Eleven introduced tropical grasses were compared in single grass swards and nine of these were compared in mixtures containing two or three grasses. The pastures received 300 lb nitrogen an acre a year as urea and were grazed five times a year. A basal legume mixture of tropical legumes and white clover sown with the grasses failed to persist. There were large differences between the grasses in competitive ability and this varied with time. Samford Rhodes grass, Nandi setaria, and Pangola were the most aggressive, and the Paspalum species-P. plicatulum P. dilatum and P. commersonii the least aggressive. Hyparrhenia hirta, which had done well at low nitrogen levels, failed to compete with weed grasses at the higher nitrogen level used in this study. Rhyncheytrum repens and commercial Rhodes grass were the dominant weed grasses in the establishment year. These rapidly decreased with time, and Digitaria didacola-blue couch, became the dominant weed species. Plots containing Nandi setaria, Samford Rhodes grass, or Pangola, gave the highest yields, and plots containing P. dilatatum the lowest. There was no yield advantage in combining grasses in mixtures-the mixture giving similar or lower yields than the best grass in the mixture grown alone. Under a period of farm grazing the three Rhodes grasses used declined sharply and the proportion of blue couch increased. The high yields from plots dominated by blue couch indicate that, agronomically, this has been a neglected naturalized species. Only Nandi setaria and Pangola were able to compete effectively with blue couch under the 'farm grazing' management imposed.

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