28 research outputs found
Current Welfare Problems Facing Horses in Great Britain as Identified by Equine Stakeholders
Despite growing concerns about the welfare of horses in Great Britain (GB) there has been little surveillance of the welfare status of the horse population. Consequently we have limited knowledge of the range of welfare problems experienced by horses in GB and the situations in which poor welfare occurs. Thirty-one in-depth interviews were conducted with a cross -section of equine stakeholders, in order to explore their perceptions of the welfare problems faced by horses in GB. Welfare problems relating to health, management and riding and training were identified, including horses being under or over weight, stabling 24 hours a day and the inappropriate use of training aids. The interviewees also discussed broader contexts in which they perceived that welfare was compromised. The most commonly discussed context was where horses are kept in unsuitable environments, for example environments with poor grazing. The racing industry and travellers horses were identified as areas of the industry where horse welfare was particularly vulnerable to compromise. Lack of knowledge and financial constraints were perceived to be the root cause of poor welfare by many interviewees. The findings give insight into the range of welfare problems that may be faced by horses in GB, the contexts in which these may occur and their possible causes. Many of the problems identified by the interviewees have undergone limited scientific investigation pointing to areas where further research is likely to be necessary for welfare improvement. The large number of issues identified suggests that some form of prioritisation may be necessary to target research and resources effectively
Antimutagenic compounds and their possible mechanisms of action
Mutagenicity refers to the induction of permanent changes in the DNA sequence of an organism, which may result in a heritable change in the characteristics of living systems. Antimutagenic agents are able to counteract the effects of mutagens. This group of agents includes both natural and synthetic compounds. Based on their mechanism of action among antimutagens, several classes of compounds may be distinguished. These are compounds with antioxidant activity; compounds that inhibit the activation of mutagens; blocking agents; as well as compounds characterized with several modes of action. It was reported previously that several antitumor compounds act through the antimutagenic mechanism. Hence, searching for antimutagenic compounds represents a rapidly expanding field of cancer research. It may be observed that, in recent years, many publications were focused on the screening of both natural and synthetic compounds for their beneficial muta/antimutagenicity profile. Thus, the present review attempts to give a brief outline on substances presenting antimutagenic potency and their possible mechanism of action. Additionally, in the present paper, a screening strategy for mutagenicity testing was presented and the characteristics of the most widely used antimutagenicity assays were described
Testing of chemicals for mutagenic activity with Schizosaccharomyces pombe.
Two genetic end-points are used for testing mutagens in Schizosaccharomyces pombe: forward mutations of the loci which encode steps early in the adenine synthetic pathway and reversions of certain selected mutants. 54 chemicals have been tested for at least one of the genetic end-points. The relevant literature has been reviewed through 1979
Testing of chemicals for genetic activity with Saccharomyces cerevisiae: a report of the U.S. Environmental Protection Agency Gene-Tox Program
The yeast Saccharomyces cerevisiae is a unicellular fungus that can be cultured as a stable haploid or a stable diploid. Diploid cultures can be induced to undergo meiosis in a synchronous fashion under well-defined conditions. Consequently, yeasts can be used to study genetic effects both in mitotic and in meiotic cells. Haploid strains have been used to study the induction of point mutations. In addition to point mutation induction, diploid strains have been used for studying mitotic recombination, which is the expression of the cellular repair activities induced by inflicted damage. Chromosomal malsegregation in mitotic and meiotic cells can also be studied in appropriately marked strains. Yeast has a considerable potential for endogenous activation, provided the tests are performed with appropriate cells. Exogenous activation has been achieved with S9 rodent liver in test tubes as well as in the host-mediated assay, where cells are injected into rodents. Yeast cells can be recovered from various organs and tested for induced genetic effects. The most commonly used genetic end point has been mitotic recombination either as mitotic crossing-over or mitotic gene conversion. A number of different strains are used by different authors. This also applies to haploid strains used for monitoring induction of point mutations. Mitotic chromosome malsegregation has been studied mainly with strain D6 and meiotic malsegregation with strain DIS13. Data were available on tests with 492 chemicals, of which 249 were positive, as reported in 173 articles or reports. The genetic test/carcinogenicity accuracy was 0.74, based on the carcinogen listing established in the Gene-Tox Program. The yeast tests supplement the bacterial tests for detecting agents that act via radical formation, antibacterial drugs, and other chemicals interfering with chromosome segregation and recombination processes
Prevalence of Different Head-Neck Positions in Horses Shown at Dressage Competitions and Their Relation to Conflict Behaviour and Performance Marks
Much controversy exists among riders, and in particular among those practicing dressage, regarding what can be considered an “appropriate” Head-Neck-Position (HNP). The objective was to assess the prevalence of different HNPs in the field, the behavioural reactions of horses during warm-up and competition rides in relation to HNP and the relation between HNP and marks achieved in the competition. Horses (n = 171) were selected during dressage competitions according to their HNP (3 categories based on the degree of flexion), and their behaviour was recorded during 3 minutes each of riding in the warm-up area and in the competition. Scans were carried out on an additional 355 horses every 15 minutes to determine the proportion of each HNP in the warm-up area. Sixty-nine percent of the 355 horses were ridden with their nasal planes behind the vertical in the warm-up area, 19% were ridden at or behind the vertical and only 12% were ridden with their nasal plane in front of the vertical. Horses carrying their nasal plane behind the vertical exhibited significantly (P<0.0001) more conflict behaviours than horses with their nose held in front of the vertical. Horses were commonly presented with a less flexed HNP during competition compared to warm-up (P<0.05). A HNP behind the vertical was penalised with lower marks in the lower (P = 0.0434) but not in the higher (P = 0.9629) competition levels. Horses in higher classes showed more (P = 0.0015) conflict behaviour than those in lower classes. In conclusion, dressage horses are commonly ridden during warm-up for competitions with their nasal plane behind the vertical, and this posture seems to cause significantly more conflict behaviour than HNPs in front of the vertical