Tensions used on girths on thoroughbred racehorses

OBJECTIVE: To determine commonly used girth tensions in Thoroughbred racehorses in the Melbourne metropolitan area. DESIGN: A prospective industry survey. METHODS: Strappers were instructed to tension girths, using the same saddle, under-saddle packing and girth, sufficiently to hold the saddle for racing. These tensions were continuously recorded by an in-line load cell in the girth. Seventeen strappers from five stables participated in the study, which was conducted on 91 horses. RESULTS: Resting girth tensions varied considerably. The mean tension on inhalation was 13 +/- 0.4 kg. Male strappers recorded higher tensions than females for all indices measured. Age and girth size of the horse did not significantly influence results. CONCLUSION: This study confirms that there is no standard for application of a girth and saddle in the Thoroughbred racing industry and the range of tensions applied was large. Strappers were unable to reliably apply the same tensions between horses. Values recorded at the extremes of the range seem inappropriate for racing conditions as low values would result in slippage of the saddle and higher values may result in girth galls and possible reduction in athletic performance. Further work is necessary to determine the point at which girth tension affects performance.     

人畜共患病的分类、流行及研究方向

人畜共患病不仅对人类健康造成巨大的威胁,也会对畜牧养殖业带来毁灭性打击。如何有效预防、控制和消灭人畜共患病已成为全人类面临的巨大挑战。本文主要概述了人畜共患病的分类、流行现状及危害,并针对一些重大人畜共患病病原体,如SARS病毒、H5N1禽流感病毒所取得的一些重要进展加以阐述,提出了今后的研究方向。     

Population Pharmacokinetics of Tobramycin in Horses

Population pharmacokinetics of tobramycin was investigated in 28 healthy horses, with an aim to assess interindividual variability in the disposition of the antibiotic. Additionally, a covariate model for improved prediction of the concentrations in a particular animal was developed. A two-compartmental model best described the data. The final population covariate regression model was based on relationships between body weight and central and peripheral volumes of distribution, and between creatinine clearance and systemic tobramycin clearance. The value of population systemic tobramycin clearance and its interindividual variation (CV) were 0.087 L.hr⁻¹.kg⁻¹ and 6.0%, respectively. The respective values for central and peripheral volumes of distribution were 0.652 L.kg⁻¹ with CV of 17.7% and 1.56 L.kg⁻¹ with CV of 4.5%. In horses with decreased glomerular filtration rate, lower tobramycin clearance is predicted with the population model that requires administration of lower dose than that accepted for treatment of horses with normal kidney function. Population pharmacokinetic analysis allows study of basic disposition of tobramycin in horses with sparse data. The prediction power of the regression model was improved by inclusion of covariables such as body weight and creatinine clearance. This model can be used in direct patient care for the construction of dosing strategy in individual clinical cases.     

Effect of the microclimate on horses during international air transportation in an enclosed container

OBJECTIVE: To determine if the microclimate is detrimental to horses during international air transportation in an enclosed container. PROCEDURE: On each of two 12 h and two 24 h flights three horses were transported in an enclosed container designed to prevent exposure to insect vectors. Heart rates were monitored throughout and blood samples were collected periodically. Air in the container was sampled for bacteria and fungal spores and the temperature and relative humidity were recorded inside and outside the container periodically during the flight. On the two 12 h flights similar observations were made on three horses transported in regular open containers, which were used as controls. RESULTS: Heart rates during the flights reflected any agitation of the horses. Agitation was only mild and generally associated with take-off and landing. There were no changes in haematological or blood biochemical values that suggested any detrimental effects of the flights. The temperature in the Airstable was relatively constant during each flight (means ranged from 18.7 to 23.4 degrees C) and was significantly warmer than in the cargo hold (range 13.9 to 18.3 degrees C). Relative humidity fluctuated more widely and reflected the ambient humidity during airport stops. The numbers of bacteria and fungal spores in the Airstable air varied during the flights but were of no apparent significance to the horses' health. CONCLUSION: The Airstable proved a convenient means to transport horses on international flights and caused no discernible ill effects on the horses studied.     

Assisted Reproduction in Horses: What Can Be Learned from Assisted Reproduction in Cattle?

Researchers and practitioners of assisted reproduction in horses have borrowed heavily from similar bovine practices over the years. However, most procedures required species-specific experiments for optimization. Furthermore, the flow of information occurs in both directions; some procedures, for example, vitrification of embryos and intracytoplasmic sperm injection, were made efficacious in horses before cattle. The great advantage of research in cattle is the availability of large numbers of animals and embryos for testing hypotheses economically. Objectives of cattle breeding generally are more scientific than those concerning horses, and it is likely that much can be learned in the future from genetic tools being developed for cattle breeding. A genetic advantage of cattle breeding over horse breeding is the extremely large genetic and phenotypic databases of some breeds, which can be matched to genomic information.     

Pharmacokinetics of Sulpiride After Intravenous,Intramuscular, and Oral Single-Dose Administration in Nurse Mares

Sulpiride (SLP) is an antipsychotic drug used in humans. Although no pharmacokinetic data are available for horses, it is commonly used to encourage ovulation in noncycling mares and to stimulate lactation in adoptive mares. The aim of this study is to assess the pharmacokinetics profile of SLP after intravenous (IV), intramuscular (IM), and oral (PO) administrations in normal horses. Animals (n = 6) were treated with 1 mg/kg SLP, administered by IV, IM, and PO routes according to a randomized crossover design (3 × 3 Latin square). Blood samples (5 mL) were collected at a programmed time and analyzed using a validated with fluorescence detection method. SLP was present at a detectable concentration up to 24 hours postadministration for all routes, except for one animal in the PO group. IV and IM administrations gave similar curves, with an IM average bioavailability of 118.0%. These high values were mainly the result of the profile generated by two horses, in which a secondary concentration peak occurred in the terminal phase of the curve. After PO administration, AUC_0-∞, and consequently bioavailability (20.4%), was low. This finding could be owing to the physicochemical features of the drug. Indeed, considering that SLP is a weak base, existing in the ionized form at gastric and physiological pH, it is unsurprising that it is poorly absorbable, especially in horses with a particularly acidic gastric pH. In conclusion, injective routes are definitely preferable to PO dosing because of the low bioavailability using this route.