Feeding value of pastures for horses

The feeding value of fresh pasture grazed in situ is determined by animal performance or productivity and could be relatively easily established for growing and lactating horses. Despite this, there is a lack of published information on the relative feeding value of different pastures and forages grazed by horses in New Zealand and the world. In addition, for adult breeding or non-breeding and young or adult sport or performance horses, the definition of feeding value and its determination remain problematic.

Limited information suggests that the feeding value of perennial ryegrass-based pasture in New Zealand for young growing horses is high, and growth rates for Thoroughbred horses fed solely on pasture in New Zealand are similar to those reported from the Northern Hemisphere where grain-based supplements are fed in addition to pasture or other forages. Attempts to assess the ability of fresh pastures to meet the nutrient requirements of horses are hampered by problems associated with determination of feed intake by grazing horses and lack of knowledge of the digestibility and utilisation of digested nutrients, including the relative bio availability of macro- and micro-minerals in pasture. A further challenge for future research is to determine the effect of herbage allowance and grazing behaviour, including pasture species preferences, on voluntary feed intake by grazing horses.

Grazing pasture has benefits for equine health and well-being including reduced risk of some nutrition-related disorders and reduced prevalence of stereotypic behaviour. Pastured horses have greater freedom for expression of natural behaviours including social interaction and exercise. However, grazing pasture is also associated with animal health problems, particularly parasitism and diseases related to pasture-associated toxins.     

蛋鸡单阶段箱体式孵化技术

文章从生物安全、孵化技术、操作流程以及孵化成绩等方面对单阶段箱体式孵化与多阶段巷道式孵化技术进行比较,发现箱体式孵化通过标准化定制的工艺程序与现场管理相结合,可明显提高孵化表现与孵化成绩。     

Producing progeny from endangered birds of prey: treatment of urine-contaminated semen and a novel intramagnal insemination approach.

Wild raptors brought into an ex situ environment often have poor semen quality that is further compromised by urine contamination. Generally, it is believed that in birds, artificial insemination into the cloaca or caudal vagina of females requires large doses of high-quality spermatozoa to maximize fertility. In an effort to define and overcome some of the challenges associated with reproduction in wild raptors, the objectives of this study were to 1) evaluate the frequency, impact, and remediation of urine contamination in fresh ejaculates for the purpose of maintaining sperm motility and viability in vitro, and 2) develop a deep insemination method that allows low numbers of washed sperm to be placed directly into the magnum to increase the probability of producing fertilized eggs. The species evaluated include golden eagle (Aquila chrysoetos), imperial eagle (A. adalberti), Bonelli's eagle (Hiernaetus fasciatus), and peregrine falcon (Falco peregrinus). Semen samples were collected and pooled by species, and a minimum of 25 pooled ejaculates per species were evaluated for urine contamination, pH, sperm viability, and sperm motility; the samples were either unwashed or washed in neutral (pH 7.0) or alkaline (pH 8.0) modified Lake's diluent. Female golden eagles and peregrine falcons were inseminated via transjunctional, intramagnal insemination with washed spermatozoa from urine-contaminated samples. Urine contamination occurred in 36.8 +/- 12.8% (mean +/- SEM) golden eagle, 43.1 +/- 9.1% imperial eagle. 28.7 +/- 16.1% Bonelli's eagle, and 48.2 +/- 17.3% peregrine falcon ejaculates. The pH in urine-contaminated semen samples ranged from 6.48 +/- 0.3 to 6.86 +/- 0.2, and in noncontaminated samples it ranged from from 7.17 +/- 0.1 to 7.56 +/- 0.1. Sperm viability and motility were reduced (P < 0.05) in all species for unwashed vs. washed sperm after 30 min incubation at room temperature. Two peregrine falcon chicks and one golden eagle chick hatched after intramagnal insemination. This study demonstrates that urine contamination, a common and lethal acidifier in manually collected raptor ejaculates, can be circumvented by immediate, gentle seminal washing. Furthermore, these processed sperm, when deposited by transjunctional intramagnal insemination, can produce live young.     

A spatial analysis of forest management and its contribution to maintaining the extent of shrubland habitat in southern New England, United States

Conservation organizations in the northeastern United States (US) recommend forest clearcutting to create shrubland habitat, which is required by many wildlife species with declining populations. The planning of habitat management programs is hampered by a lack of information on the current extent of shrubland habitat and the current rate of forest clearcutting that creates shrubland habitat. We addressed these information gaps by using a combination of automated and manual approaches to determine the extent and spatial configuration of shrubland habitat and recent forest clearcuts. We focused on the state of Rhode Island because (a) it is representative of the northeastern US in terms of the prevalence of private ownership of forests, and the ongoing decline in the populations of many shrubland wildlife species; (b) federal, state and private conservation groups are actively promoting clearcuts to create shrubland habitat; (c) many state-wide GIS databases are available; and (d) the spatial extent of the state made our results both generalizable and politically relevant. Our fine-scale mapping allowed a detailed analysis of shrubland distribution in conjunction with other available GIS layers that facilitates identification of priority areas for habitat management. We found that the extent of upland shrubland in non-coastal areas is decreasing by at least 1.5% annually. Considering the lack of consensus about conservation targets for the amount of shrubland, we propose that conservation organizations attempt to stabilize rather than expand the extent of shrubland habitat. This approach would provide an opportunity to assess whether the current extent of shrubland is sufficient to maintain reduced but stable wildlife populations that require this habitat. We propose a coordinated forest management program with targets for increased forest management on conservation lands. We found that the average patch size of shrubland created by recent clearcuts is large enough for most shrubland bird species, but too small for the New England cottontail (Sylvilagus transitionalis), which has been proposed for threatened and endangered status.     

Requirement for cotolerogenic gene products in the clonal deletion of I-E reactive T cells

T cells that express the T cell receptor V beta 5.2 domain react with the class II major histocompatibility complex (MHC) molecule I-E, and V beta 5.2+ T cells are deleted in mouse strains that express I-E glycoproteins. By examination of genetically defined recombinant inbred (RI) mouse strains, it was found that the deletion was dependent on the expression of I-E and one of a limited number of non-MHC gene products (cotolerogens). The gene encoding one of these cotolerogens maps to chromosome 12 and is linked to the endogenous provirus Mtv-9. These observations suggest that the I-E-mediated and minor lymphocyte-stimulating antigen (Mls)-mediated deletions of alpha beta T cells from the repertoire are similar; both require the expression of a class II MHC glycoprotein and a second non-MHC gene product.     

The environmental movement and labor in global capitalism: Lessons from the case of the Headwaters Forest

Employing the case of theredwood Headwaters forest in rural NorthernCalifornia, this paper investigates the extentto which an anti-corporate progressive alliancebetween labor and the environmental movement ispossible in contemporary global capitalism.Progressive alliances between labor and theenvironmental movement have been historicallydifficult. This has been particularly the casein the timber industry, where companies havebeen able to mobilize workers againstenvironmentalists' designs. The caseillustrates the events that led to the purchaseof the Headwaters Forest by the state ofCalifornia and the Federal Government fromPacific Lumber. This is a subsidiary of Maxxam,a corporation with interests in a variety ofeconomic sectors. The objective was to haltMaxxam's rampant deforestation of old growthredwood. Though conflict between labor andenvironmentalists existed, the casedemonstrates that the labor and theenvironmental movement were united againstMaxxam. They, however, were not completelysuccessful in their struggle as Maxxam greatlybenefited from the state-sponsored landpurchase. Maxxam gained economically, was ableto shape the ideological framework throughwhich the purchasing agreement was achieved,and extended its hegemony over the state. Thisoutcome cast doubts on the possibility thatcurrent forms of environmental protection couldtranscend commodified and reductionistpostures. Simultaneously, the existence of acommon anti-corporate consciousness among largesegments of labor and the environmentalmovement makes the environment a contestedterrain and allows for some optimism about thefuture of the struggle for ecologically soundsocial arrangements.     

Development of an enzyme-linked immunosorbent assay for the detection of the organophosphorus insecticide acephate

A competitive indirect enzyme-linked immunosorbent assay (ciELISA) for the organophosphorus insecticide acephate, O,S-dimethyl acetylphosphoramidothioate, was developed using a polyclonal antibody. Five different haptens mimicking the analyte were synthesized and conjugated with the carrier proteins bovine serum albumin (BSA) and keyhole limpet hemocyanin (KLH) by the N-hydroxysuccinimide active ester and diazotization methods. Polyclonal antibodies raised against hapten-KLH conjugates in rabbits and hapten-BSA conjugates as coating antigens were screened and selected for the assay in the homologous and heterologous ELISA systems. The effects of various assay conditions such as detergent, organic solvents, pH, and preincubation of the mixture of the polyclonal antibody and the analyte on the sensitivity were evaluated. The IC(50) value for acephate was 25 ng/mL in an optimized heterologous system using hapten-4-BSA as a coating antigen and a polyclonal antibody no. 8377 against hapten-1-KLH, showing the detection range of 5-140 ng/mL and the lowest detection limit of 2 ng/mL. The cross-reactivities of the structurally related organophosphorus insecticides, including the major metabolite of the analyte, methamidophos, were less than 1%. Recoveries from the analyte-fortified tap water, mulberry leaves, and lettuce samples in the assay were in the range of 72-121% by simple extraction, concentration, and dilution. These results indicate that the ELISA could be a convenient and supplemental analytical tool for monitoring acephate residues in environmental and agricultural samples.