No abstract

SummaryReasons for performing study: Oxidative stress (OS) is most simply defined as an imbalance between oxidants and antioxidants. Oxidative stress has been suggested to play roles in various equine respiratory diseases and the significance of OS in the pathogenesis of Rhodococcus equi pneumonia is unknown. Objectives: To measure and relate biomarkers of OS to lesions consistent with R. equi pneumonia. Study design: Case-control study. Methods: Various OS biomarkers were measured from blood and exhaled breath condensate (EBC) samples collected from 26 foals between 1 and 2 months of age (n = 12 cases and n = 14 controls) on 2 Thoroughbred farms endemically affected by R. equi pneumonia. Foals were defined as cases (positive) or controls (negative) based on ultrasonographic evidence of pulmonary abscessation (>15 mm in diameter). Haematology and biochemistry testing was also performed on blood samples collected from the foals. Comparison of biomarkers and key haematological and biochemical markers of inflammation between the groups was performed using 2 sample t tests. Results: Derivatives of reactive oxygen metabolites (d-ROMs) were significantly greater in case foals than in control foals (P = 0.027) and the oxidative stress index (OSI) was higher in case foals (P = 0.014). Hydrogen peroxide (H2O2) concentrations in EBC were significantly greater in case foals than in control foals (P = 0.002). Meanwhile, there were no significant differences in traditional measures of inflammation between the 2 groups. Conclusions: Measuring OS in both blood and EBC provided useful information in the early diagnosis of R. equi pneumonia.

Yerba Mate (Ilex paraguariensis), a tea known for its high antioxidant content, was supplemented to 30 of 60 ewes for 13 wks to assess its effect on their productive performance. A 2.5% inclusion rate of Yerba Mate (YM) in a pelleted concentrate diet decreased feed intake and live weight (LW) during the first few weeks post partum (p<0.001). Overall, the YM group ate less (2,09278 g/d) pellet than the control (CTRL) one (2,43483 g/d); similarly, LW was lower in the YM group compared to the CTRL one, 64.91.6 kg and 67.31.4 kg, respectively. Lambs' birth weight and growth rates were not affected. At birth, lambs' LW were similar between the Yerba Mate and control groups (4.20.5 kg and 4.10.4 kg, respectively. At the end of the trial, Yerba Mate lambs weighed 15.70.4 kg while CTRL lambs weighed 16.10.4 kg. Average daily growth rate was similar between the two groups and ranged from 17619 to 234 24 g/d. The inclusion of Yerba Mate in a pelleted diet increased milk fat, protein and total solids content while it decreased milk lactose content. Further work is required to investigate the mechanisms by which Yerba Mate supplementation affects feed intake and milk composition.

No abstract

This large-scale outbreak of EHDV in US cattle was unusual because calves were affected. Because there is no way to effectively predict or prevent an EHDV outbreak in cattle, development of a vaccine for use in cattle during an outbreak would be beneficial.