Orally administered phenylbutazone causes oxidative stress in the equine gastric mucosa

Phenylbutazone (PBZ) is widely used in equine medicine, and its side effects on the gastrointestinal tract are well known. The inhibition of prostaglandins and the oxidative stress induced by nonsteroidal anti‐inflammatory drugs (NSAIDs) are described as mechanisms of gastric mucosal injury in humans. In horses, only the secondary effect of changes in cyclooxygenases is related to gastric mucosal injury. The objective of this study was to evaluate the effect of PBZ on certain antioxidative/oxidative parameters of the gastric mucosa. The concentrations of antioxidants and oxidants (superoxide dismutase, SOD; catalase, CAT; nitric oxide, NO; total glutathione, GSH; myeloperoxidase, MPO; and malondialdehyde, MDA), PGE₂ levels, and the ulcerative lesions score were assessed. The results demonstrated decreased levels of antioxidant variables, increased levels of oxidant variables, and alterations in the prostaglandin E₂ (PGE₂), myeloperoxidase (MPO), and glutathione (GSH) levels. In conclusion, PBZ induces oxidative stress in the gastric glandular mucosa of horses by changing the antioxidant–oxidant balance of this surface, which might be regarded as another mechanism of injury in the horse stomach.     

The effect of short duration transportation on serum cortisol response in alpacas (Llama pacos)

This research project evaluated the changes in serum cortisol in six male and six female alpacas in response to transportation of short duration. All alpacas were subjected to trailer transportation for 30 min. Serum samples were obtained prior to transportation, immediately after transportation, and after a 4-h recovery period. Heart rate was recorded at each time interval and observations of individual behavioural characteristics were recorded. Data were analysed using analysis of variance. Heart rate was not significantly changed by transportation stress. Serum cortisol concentration was significantly higher after transportation, but head returned to baseline concentration after the 4-h recovery period. Behavioural characteristics were not associated with changes in serum cortisol concentration.     

Genetic analysis of growth,visual scores,height, and carcass traits in Nelore cattle

Covariance components were estimated for growth traits (BW, birth weight; WW, weaning weight; YW, yearling weight), visual scores (BQ, breed quality; CS, conformation; MS, muscling; NS, navel; PS, finishing precocity), hip height (HH), and carcass traits (BF, backfat thickness; LMA, longissimus muscle area) measured at yearling. Genetic gains were obtained and validation models on direct and maternal effects for BW and WW were fitted. Genetic correlations of growth traits with CS, PS, MS, and HH ranged from 0.20 ± 0.01 to 0.94 ± 0.01 and were positive and low with NS (0.11 ± 0.01 to 0.20 ± 0.01) and favorable with BQ (0.14 ± 0.02 to 0.37 ± 0.02). Null to moderate genetic correlations were obtained between growth and carcass traits. Genetic gains were positive and significant, except for BW. An increase of 0.76 and 0.72 kg is expected for BW and WW, respectively, per unit increase in estimated breeding value (EBV) for direct effect and an additional 0.74 and 1.43, respectively, kg per unit increase in EBV for the maternal effect. Monitoring genetic gains for HH and NS is relevant to maintain an adequate body size and a navel morphological correction, if necessary. Simultaneous selection for growth, morphological, and carcass traits in line with improve maternal performance is a feasible strategy to increase herd productivity.     

Evaluation of Three Enzyme Immunoassays for Diagnosis of Clostridium difficile–Associated Diarrhea in Foals

The aim of the present study was to compare the test performances of three commercial enzyme immunoassays (EIAs) against the toxigenic culture using the cytotoxicity assay as the gold standard. All EIAs showed >78% sensitivity, and the lowest specificity was 92.6%. These results suggest that EIAs could be useful for the diagnosis of Clostridium difficile infection in foals.     

Effect of pyruvate and lactate on motility of cold stored stallion spermatozoa challenged by hydrogen peroxide

Numerous workers have shown that motility of cold stored spermatozoa from some stallions can be improved by removing most of the seminal plasma by centrifugation and resuspending the spermatozoa in an extender consisting of skim milk glucose extender (SKMG) supplemented with a salt media such as Tyrode's or phosphate-buffered saline. The salt media must contain pyruvate and lactate. In an effort to test the hypothesis that pyruvate may be acting as an antioxidant, a series of experiments were conducted using a H₂O₂ challenge to artificially produce damage due to lipid peroxidation. Results of these experiments indicated that addition of lactate or pyruvate and lactate to SKMG-Tyrode's media was not able to prevent the detrimental affects of H₂O₂. The addition of lactate to the SKMG-Tyrode's media resulted in an improvement of post-storage motility; however, increasing the concentration of pyruvate did not further improve motility. Therefore, because lactate dehydrogenase has been shown to be correlated with motility, and lactate has been shown to be preferred as an energy source by spermatozoa from other species, the beneficial effects of lactate and pyruvate as components of a modified SKMG extender are probable as energy sources.