Incidence of exercise induced pulmonary haemorrhage in racing horses in Puerto Rico

Abstract

Exercise-induced pulmonary hemorrhage in equines (EIPH) is a condition that is defined as the presence of blood in the tracheobronchial tree from the alveolar capillaries. Currently, there is no specific reason to which this condition is attributed and generates economic losses to the horse industry. In Puerto Rico, there is no information on the incidence and degrees of severity of the equine condition competing in the Camarero racetrack, Canóvanas, Puerto Rico. The use of furosemide diuretic is the only measure to prevent or treat the condition of EIPH on the island. However, there is no documented scientific evidence on the efficacy of this drug. Also, the year, month, sex, race distance, use of data and the values of the temperature and humidity index (THI) on the comfort zone of the animals are factors that can be related to the incidence of EIPH in equines. The objective of this research was to determine the incidence and severity of EIPH in race horses at the Camarero racetrack. In addition, the effect of year, month, sex, diuretic use and distance of the race on the incidence and degree of severity was determined (0 = no presence of bleeding, 1 = presence of blood in the carina of trachea; 2 = presence of blood in carina of trachea and trachea, 3 = presence of blood in carina of trachea: proximal trachea and larynx, 4 = presence of blood in carina of trachea, proximal trachea and larynx and nostrils, 5 = epistaxis) of EIPH and its relationship with the index of temperature and humidity. For the study, data from 5,223 endoscopies previously performed were used. The data was provided by the Equus Veterinary Clinic, at the Camarero racetrack. The collected data from each horse was: the year it competed (2014, 2015 or 2016), the month of the year, the sex of the animal, the distance of the race (1 = 400 to 1,200 m, 2 = 1,300 to 1,400 m, 3 = 1,600 m or more) and if diuretics were used 4 hours before the competition. The corresponding THI value with the municipality of Canóvanas was determined in each of the 36 months of the study. A Chi-square test was used to determine the frequency of the incidence and degree of severity of the EIPH condition in competing equines. There was an effect of the year and month on the incidence of the EIPH condition. In 2016, the incidence was higher (P> 0.05) than in 2014 and 2015. During the period from July to November, the average incidence of HPIE (47.84%) was higher than December to June (41.65%). The condition of EIPH was observed in horses of both sexes and in the three distances of races in similarly. The presence of the condition was similar in equines treated or not with the diuretic. During the 36 months of the study, the THI value was greater than the thermal comfort zone for domestic animals. However, it was slightly lower between the months of January and May and also November and December. The period with the highest THI (July to November) coinciding with the increase of 6.19% in the incidence of equines with the condition under the month effect.