Comparison of production and calving data for 10 Irish dairy herds in the vicinity of an industrial chemical complex and 10 herds in rural, non-industrialised areas

Production and calving data for 2001 to 2004 inclusive were collated for 10 dairy herds located in the vicinity of a complex of chemical industries in the Cork harbour region (target herd) and 10 herds located in rural, non-industrialised areas (control herds). The average milk yield per cow, stocking rates and culling rates were similar for the two groups of herds. The prime reasons for the disposal of animals from both groups of herds were infertility, 'old age', mastitis, lameness and low milk production, and the proportions of deaths recorded were similar. Overall, significantly more male calves were born (52 per cent), but there were no significant differences between the groups in the sex ratio, the incidence of calving difficulty or the incidence of retained placentas. A higher proportion (P<0.05) of stillbirths was observed in the control herds (5.7 per cent) than in the target herds (4.7 per cent), but there was no significant difference in perinatal mortality. There was a higher proportion of multiple births (P<0.05) in the target herds (3.93 per cent) than in the control herds (2.27 per cent). No cause-and-effect relationships between location and multiple birth rate or location and stillbirth incidence were found.     

Development of a gene silencing DNA vector derived from a broad host range geminivirus

Background  

Gene silencing is proving to be a powerful tool for genetic, developmental, and physiological analyses. The use of viral induced gene silencing (VIGS) offers advantages to transgenic approaches as it can be potentially applied to non-model systems for which transgenic techniques are not readily available. However, many VIGS vectors are derived from Gemini viruses that have limited host ranges. We present a new, unipartite vector that is derived from a curtovirus that has a broad host range and will be amenable to use in many non-model systems.     

Comparison of selenium determination in liver samples by atomic absorption spectroscopy and inductively coupled plasma-mass spectrometry.

Selenium (Se) is an essential trace element that is often deficient in the natural diets of domestic animal species. The measurement of Se in whole blood or liver is the most accurate way to assess Se status for diagnostic purposes. This study was conducted to compare hydride generation atomic absorption spectroscopy (HG-AAS) with inductively coupled plasma-mass spectrometry (ICP-MS) for the detection and quantification of Se in liver samples. Sample digestion was accomplished with magnesium nitrate and nitric acid for HG-AAS and ICP-MS, respectively. The ICP-MS detection was optimized for 82Se with yttrium used as the internal standard and resulted in a method detection limit of 0.12 microg/g. Selenium was quantified by both methods in 310 samples from a variety of species that were submitted to the Toxicology Laboratory at New Bolton Center (Kennett Square, PA) for routine diagnostic testing. Paired measurements for each sample were evaluated by a mean difference plot method. Limits of agreement were used to describe the maximum differences likely to occur between the 2 methods. Results suggest that under the specified conditions ICP-MS can be reliably used in place of AAS for quantitation of tissue Se at or below 2 microg/g to differentiate between adequate and deficient liver Se concentrations.     

Differentiation of porcine enterovirus serotypes by complement fixation

A complement fixation test in microtitre plates for the differentiation of porcine enterovirus serotypes is described, employing guinea pig antisera prepared using inactivated purified viruses. Eleven porcine enterovirus serotypes and swine vesicular disease virus were compared and clearly distinguished from each other. In addition, 71 porcine enterovirus strains and isolates were tested and each was identified as belonging to one of the 11 serotypes.     

How riding may affect welfare: What the equine veterinarian needs to know

Veterinarians generally focus on keeping the performance horse in work but they need to be mindful of ways in which the work itself may jeopardise the animal's welfare and health. Elements of a horse's work may expose it to the risk of injury but insults to wellbeing, which are far more common and far more sustained, although less overt, also deserve consideration. A good example is the way in which chronic physiological stress responses arising from inhumane training techniques may compromise immunity and tissue repair. This article explores the physiological and musculoskeletal insults that can result from ridden work, alongside the gear and training paradigms that can compromise welfare. It also considers issues relating to the use of pharmaceuticals in the ridden horse. With stress reduction as a primary focus, it emerges that veterinarians are uniquely placed to comment on the somatic effects of psychological stressors, including the social and ethological challenges resulting from the work required of the so‐called elite equine athlete. Whether the profession will step up to meet this significant challenge is also discussed.     

Analysis of Canadian and Irish forage,oats and commercially available equine concentrate feed for pathogenic fungi and mycotoxins

Respiratory infections, recurrent airway obstruction (RAO) and exercise induced pulmonary haemorrhage (EIPH) are major causes of poor performance in horses. Fungi and mycotoxins are now recognised as a major cause of these conditions. The most notable fungi are Aspergillus and Fusarium. Fungal spores can originate from forage, bedding and feed and, in turn, these fungal spores can produce a series of mycotoxins as secondary metabolites.This study set out to ascertain the degree of fungal and mycotoxin contamination in feed and fodder used in Irish racing yards over a one-year period. Weather conditions in forage producing areas were sampled by Met Eireann and the Canadian Meteorological Service.Fifty per cent of Irish hay, 37% of haylage and 13% of Canadian hay contained pathogenic fungi. Of the mycotoxins, T2 and zearalenone were most prominent. Twenty-one per cent of Irish hay and 16% of pelleted feed contained zearalenone. Forty per cent of oats and 54% of pelleted feed contained T2 toxins.     

Clinical,metabolic, and genetic characterization of hereditary methemoglobinemia caused by cytochrome b5 reductase deficiency in cats

Two non‐pedigreed male castrated cats had persistent cyanosis over a 3‐year observation period. Clinical cardiopulmonary evaluations did not reveal abnormalities, but the blood remained dark after exposure to air. Erythrocytic methemoglobin concentrations were high (~40% of hemoglobin) and cytochrome b₅ reductase (CYB5R) activities in erythrocytes were low (≤15% of control). One cat remained intolerant of exertion, and the other cat developed anemia and died due to an unidentified comorbidity. Whole‐genome sequencing revealed a homozygous c.625G>A missense variant (B4:137967506) and a c.232‐1G>C splice acceptor variant (B4:137970815) in CYB5R3, respectively, which were absent in 193 unaffected additional cats. The p.Gly209Ser missense variant likely disrupts a nicotinamide adenine dinucleotide (NADH)‐binding domain, while the splicing error occurs at the acceptor site for exon 4, which likely affects downstream translation of the protein. The 2 novel CYB5R3 variants were associated with methemoglobinemia using clinical, biochemical, genomics, and in silico protein studies. The variant prevalence is unknown in the cat population.     

Effect of dietary oils and alpha-tocopheryl acetate supplementation on lipid (TBARS) and cholesterol oxidation in cooked pork

The effect of n-3 fatty acid-enriched diets (in the form of 0.5% linseed oil with either 1.5% sunflower oil or 1.5% olive oil) and alpha-tocopheryl acetate supplementation (200 mg/kg feed) on lipid oxidation (thiobarbituric acid-reactive substances, TBARS) and cholesterol oxide products (COPS) in cooked pork was investigated. Longissimus muscle was studied. Meat from pigs fed 0.5% linseed oil-enriched diets had a higher proportion of n-3 fatty acid than meat from pigs in other dietary groups in neutral (P < 0.0001) and polar lipids (P < 0.0001), and a 20% reduction in the n-6:n-3 ratio was observed. Alpha-tocopheryl acetate supplementation increased (P < 0.05) monounsaturated fatty acids in polar lipids and increased (P = 0.0001) alpha-tocopherol levels in muscle. Alpha-tocopherol concentration in muscle was affected by dietary fat (P < 0.05). Groups receiving diets enriched with sunflower oil had significantly higher alpha-tocopherol levels (P < 0.05) in muscle than those groups receiving olive oil-enriched diets. Numbers of TBARS were significantly (P < 0.05) lower in the group fed supplemental olive oil than in those fed sunflower oil. Dietary linseed oil increased (P < 0.05) lipid oxidation principally at the initial period of storage in cooked pork. Overall, dietary alpha-tocopheryl acetate supplementation significantly increased (P < 0.001) lipid stability and decreased (P < 0.05) total COP production across the dietary groups. Alpha-tocopherol was a more effective antioxidant for decreasing TBARS values in cooked meat when adding sunflower oil to the diets instead of olive oil.     

Rhodococcus equi infection in foals: the science of 'rattles'

Infection with Rhodococcus (Corynebacterium) equi is a well-recognised condition in foals that represents a consistent and serious risk worldwide. The condition manifests itself primarily as one of pulmonary abscessation and bronchitis, hence the terminology of 'rattles' derived from its most obvious clinical sign, frequently terminal when first identified. This review addresses the clinical manifestation, bacteriology and pathogenesis of the condition together with recent developments providing knowledge of the organism in terms of virulence, epidemiology, transmission and immune responses. Enhanced understanding of R. equi virulence mechanisms and biology derived from the recently available genome sequence may facilitate the rational development of a vaccine and the improvement of farm management practices used to control R. equi on stud farms in the future. Reliance on vaccines alone, in the absence of management strategies to control the on-farm challenge is likely to be disappointing.