Gastric ulcers in standardbred racehorses: prevalence,lesion description,and risk factors

This study was performed to estimate the prevalence of gastric ulcers in Standardbred racehorses, to describe the lesion score and location, and to identify potential risk factors. Two hundred seventy-five (275) Standardbred horses from 5 training centers and 2 racetracks in Quebec, Canada, were studied. Historical data for the 2 months before examination were recorded for each horse, and the presence of gastric ulcers was determined by gastroscopy. A previously reported scoring system that used grades 0-3 for gastric lesions was used. Overall, 121 horses (44.0%; 95% CI, 38.1-50.1%) had gastric ulcers. The prevalence of gastric ulcers was significantly higher (P < .0001) in actively racing horses (63.3%; 95% CI, 54.7-71.2%) than in horses at rest. Multivariate analysis defined that horses in racing (OR = 9.29; 95% CI, 3.55-24.3) were significantly more likely to have gastric ulcers than horses at rest and that trotters (OR = 2.23; 95% CI, 1.28-3.86) were more likely to have gastric ulcers than pacers. The number of lesion sites (P < .0001) and poor body condition (P < .0001) were significantly associated with lesion scores. Gastric ulcers are highly prevalent in Standardbred racehorses. Furthermore, actively racing horses and trotters are more likely to have gastric ulcers. Also, poor body condition in Standardbred racehorses may be an indication that gastric ulcers are present and that lesion scores are high. The cause-and-effect relationship between poor body condition and the presence of gastric ulcers is unclear.     

Field efficacy of ivermectin plus praziquantel oral paste against naturally acquired gastrointestinal nematodes and cestodes of horses in North America and Europe

The efficacy of an oral formulation of ivermectin plus praziquantel in the reduction of nematode and cestode egg counts in horses was assessed in 273 horses under field conditions at 15 sites in North America (n = 6) and Europe (n = 9). Horses were confirmed by fecal examination to have natural infections of strongyles (100%) and tapeworms (76%). Replicates of four horses were formed at each site, and in each replicate three animals received ivermectin (0.2 mg/kg body weight) plus praziquantel (1 mg/kg body weight) oral paste and one animal remained untreated or received vehicle paste. Fecal samples were collected for fecal nematode and cestode egg counting before and 7, 8, 9, 14, 15, and 16 days after treatment. Horses treated with ivermectin plus praziquantel oral paste had significantly (P <.01) lower posttreatment strongylid and cestode egg counts (reductions of 98% or more) than controls. Combined site analyses revealed that 95% or 96% of the horses positive for cestode eggs before treatment that were treated with ivermectin plus praziquantel were negative for cestode eggs at each posttreatment fecal examination. No adverse reactions attributable to ivermectin plus praziquantel oral paste treatments were observed. The results of the studies demonstrated that ivermectin plus praziquantel paste was highly effective in reducing egg shedding by gastrointestinal nematodes and cestodes, and no adverse reactions were observed in horses treated under field conditions.     

Impact of a sustained-release ivermectin bolus on weight gain in breeding age Holstein heifers under commercial pasture conditions in southern Québec.

This field trial was designed to test the effect of treatment with a sustained-release ivermectin bolus on average daily and total weight gain in breeding age Holstein heifers under commercial pasture conditions in southern Quebec. One hundred and twelve heifers from 12 herds were randomly assigned at turnout either to treatment with a commercially-available ivermectin bolus or to remain as untreated controls. Ninety-six heifers, 49 treated animals and 47 controls, completed the trial. Animals were weighed at turnout, midseason, and at the end of the grazing season. Fecal samples were collected at each of these times and nematode eggs counted. Nematode egg excretion was relatively low throughout the pasture season, which was abnormally warm and dry until midsummer. Over the entire pasture season, average daily weight gain was higher in treated than in control animals (difference = 0.08 kg/day, P = 0.010). Total weight gain was also higher in treated animals than in control animals (difference = 12.82 kg, P = 0.013). The results of this study suggest that preventive treatment of breeding age, grazing dairy heifers with a sustained-release ivermectin bolus provides a significant weight gain advantage, in situations with moderate utilization of moderately contaminated pastures.     

Enzyme-induced gelation of extensively hydrolyzed whey proteins by Alcalase: peptide identification and determination of enzyme specificity

Extensive hydrolysis of whey protein isolate by Alcalase was shown to induce gelation mainly via hydrophobic interactions. The aim of this work was to characterize the peptides released in order to better understand this phenomenon. The apparent molecular mass distribution indicated that aggregates were formed by small molecular mass peptides (<2000 Da). One hundred and thirty peptides with various lengths were identified by reversed-phase high-performance liquid chromatography coupled with electrospray ionization mass spectrometry. Alcalase was observed to have a high specificity for aromatic (Phe, Trp, and Tyr), acidic (Glu), sulfur-containing (Met), aliphatic (Leu and Ala), hydroxyl (Ser), and basic (Lys) residues. Most peptides had an average hydrophobicity of 1-1.5 kcal/residue and a net charge of 0 at the pH at which gelation occurred (6.0). Therefore, an intermolecular attractive force such as hydrophobic interaction suggests the formation of aggregates that further leads to the formation of a gel.     

Prevalence of ulcers of the squamous gastric mucosa in standardbred horses

This study was performed to determine the prevalence of ulcers in the gastric squamous mucosa in Standardbred racehorses. Observations were performed at monthly intervals between the beginning of their training season and their 1st qualifying race. This study also identified risk factors at different levels of race training. Forty-eight Standardbred racehorses from 3 training stables in Quebec, Canada, were studied. Baseline historical information and gastroscopic findings were recorded at the beginning of the trial, and once a month thereafter, between December 2001 and June 2002, until the horse's 1st qualifying race or the end of the training. Intensity of training ranged from jogging to intensive training just before the 1st race and was assigned an ordinal score. Location of squamous ulcers and their appearance were observed on gastroscopy, and an ordinal score was assigned. Prevalence of squamous ulcers from the 2nd through the 4th month (72-88%) of training remained at a significantly higher level (P = .002 to .04) than at the onset of the study (38%) and was also higher in intensely trained horses than in joggers (93% versus 56%). Moderate or more intensive training increased the odds (odds ratio [OR], 3.39; confidence interval [CI], 1.34-8.56; and OR, 11.4; CI, 3.21-40.5, respectively) of detecting ulcers with higher scores. These odds were also higher in trotters (OR, 2.17; CI, 1.07-4.43) than in pacers and generally increased with the duration of training. Duration of training, training level, and gait type also influenced the number of sites with ulcers in the same way. Ulcers had higher scores along the lesser curvature (LC) and the margo plicatus (MP) areas of the stomach. It was concluded that squamous ulcers appeared early in the training of Standardbred racehorses, that the number of sites affected and the ulcer score are related to the intensity of training, and that trotters are more prone to squamous ulcers than pacers.     

Comparative pharmacokinetics of two intravenous administration regimens of tiludronate in healthy adult horses and effects on the bone resorption marker CTX-1

Bioavailability and pharmacological effects of tiludronate were compared when administered as an intravenous (i.v.) bolus at a dosage of 0.1 mg/kg body weight (b.w.) once daily for 10 consecutive days (group 1, n  = 6) and as a single constant rate infusion (CRI) at a total dose of 1 mg/kg b.w. (group 2, n  = 6) in healthy adult horses.
Tiludronate and carboxy-terminal cross-linking telopeptide of type I collagen (CTX-1) were measured in plasma and urine.
There was no statistically significant difference in area under the curve ( AUC ) and clearance ( Cl ) between the two groups. Bioavailability of the CRI was 103% (not significantly different) that of the 10 daily i.v. bolus doses. Cumulative urine tiludronate excretion could not be compared between groups because of poor sensitivity of the assay in urine. Plasma and urine CTX-1 levels were not different between groups throughout the study. However, interindividual variations were greater in group 1 than in group 2. A significant decrease in CTX-1 levels was observed in plasma after the first administration in group 1, but not in urine; while in group 2, a significant decrease in CTX-1 concentrations was observed after treatment in both plasma and urine.
In conclusion, both dosage regimens of tiludronate produced similar plasma exposure and pharmacological effects in adult healthy horses.     

Punctodera achalensis n. sp. (Nematoda: Punctoderidae), a new cyst nematode from Argentina

European Journal of Plant Pathology - Trichoderma aggressivum, a mycopathogen causing green mould disease, is a major problem in Agaricus bisporus cultivation due to crop loss, and resistance to...     

Pharmacokinetics of clomipramine and desmethylclomipramine after single-dose intravenous and oral administrations in cats

A cross-over study was performed in six adult spayed cats to determine the pharmacokinetics of clomipramine and its metabolite, desmethylclomipramine (DCMP) after intravenous (0.25 mg/kg) and oral (0.5 mg/kg) single-dose administrations. Plasma clomipramine and DCMP were measured by high-performance liquid chromatography at regular intervals for up to 30 h. Intravenous clomipramine best fit a two-compartmental model yielding an elimination rate constant of 0.037-0.09 h(-1) from which a mean half-life of 12.3 h was calculated. Mean clomipramine AUC(0--infinity) (ngxh/mL), clearance (L/hxkg), V(ss) (L/kg) and MRT (h) values were 652.5, 0.393, 5.0, and 13.5, respectively. Compartmental modeling for clomipramine, after oral administration, and DCMP after both administrations, produced wide parameter estimates and plots of residuals indicated poor goodness of fit. Noncompartmental analysis yielded mean AUC(0--30 h) (ngxh/mL), C(max) (ng/mL) and T(max) (h) of 948.3, 87.5 and 6.2 for clomipramine, and 613.8, 34.8, and 12.8 for DCMP respectively after oral administration. Clomipramine bioavailability was 90%. The present study showed marked pharmacokinetic variability for clomipramine and DCMP through biphasic absorption and potential genetic variability in clomipramine metabolism. It was concluded that population pharmacokinetics would allow better characterization of clomipramine variability that may explain the variability in clinical response noted in cats.