This is interesting info published last year.
They took 37 baby 2-year-old thoroughbreds, and exercised them at the track for 5 months. Then they breezed them over 2-3 furlongs, and looked to see if they had evidence of bleeding in their lungs. No lasix or history of racing, no training on lasix.
(sounds like the 2-year-old in training sales, doesn't it?)
24 hours after their breezes, 23 had evidence of microscopic bleeding down in the lung. 14 did not.
Now, they also found that the horses that bled? Had increased inflammation in the lung, and decreased immune response capability against bacteria and other particles that can get down in the lung. All at the microscopic level.
That's a respiratory infection waiting to happen.
That is a good reason why lasix should be permitted as a race day
therapeutic medication.
Quote:
Vet J. 2011 Nov;190(2):e3-6.
Pulmonary inflammation due to exercise-induced pulmonary haemorrhage in Thoroughbred colts during race training.
Michelotto PV Jr, Muehlmann LA, Zanatta AL, Bieberbach EW, Kryczyk M, Fernandes LC, Nishiyama A.
Source: Department of Physiology, Universidade Federal do Paraná, Curitiba, Brazil. michelottojunior@yahoo.com.br
Abstract: This study investigated the putative roles of inflammation and platelet-activating factor (PAF) in exercise-induced pulmonary haemorrhage (EIPH). Two-year-old Thoroughbred colts (n=37) were exercised on a racetrack for 5months before commencement of the study. Each colt was then exercised at 15-16m/s over 800-1000m and broncho-alveolar lavage fluid (BALF) was collected 24h later.
The colts were subsequently divided into two groups on the basis of BALF analysis; an EIPH-positive group (presence of haemosiderophages, n=23) and an EIPH-negative group (absence of haemosiderophages, n=14).
BALF from the EIPH-positive group had a significantly higher protein concentration (0.39±0.28 vs. 0.19±0.12mg/mL, P=0.031), higher PAF bioactivity (0.18±0.12 vs. 0.043±0.05 340:380nm ratio, P=0.042) and a higher lipid hydroperoxide concentration compared to the EIPH-negative group.
There was also a lower nitrite concentration and reduced production of superoxide anion and hydrogen peroxide by alveolar macrophages in the EIPH-positive group.
There was evidence of pulmonary inflammation and a decreased innate immune response of alveolar macrophages in EIPH-positive colts compared with the EIPH-negative group.
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