The effects of frusemide on racing times of Standardbred pacers.
Seven hundred and eighty-eight Standardbred pacers competing in 8378 races at one racetrack were analysed to determine the effects of the administration of prerace frusemide on racing times (RT). Frusemide was administered i.v. 4 h before the race to pacers diagnosed with exercise-induced pulmonary haemorrhage (EIPH). Of the pacers, starting in the 1997 racing season, 32.5% received prerace frusemide. This study demonstrated that administration of frusemide prior to racing significantly decreased RT. There was an overall significant decrease (P<0.00001) in RT of 0.67 s. The overall RT for horses, geldings, and females, were mean +/- s.e 117.91 +/- 0.06, 118.20 +/- 0.03 and 118.86 +/- 0.04, respectively. RT progressively decreased until age 6 and increased thereafter. Horses, geldings and females ran a mean of 0.46, 0.31 and 0.74 s faster, respectively, with prerace administration of frusemide. This decrease in RT following prerace administration was most pronounced in younger pacers. In this study, a greater percentage of older pacers received prerace frusemide; however, the effect of frusemide on RT was decreasing with age. Prerace venous acid-base screening was performed in 2729 of the pacers competing. Pennsylvania Harness Racing Commission Regulations disqualify Standardbreds from racing with a base excess of over 10 and 12 mmol/l for Standardbreds without and with prerace administration of frusemide. The prerace venous acid-base levels were not significantly related to RT and, for those Standardbreds also sampled following the race, there was no correlation between pre- and postrace acid-base status.
Soma
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LR
University of Pennsylvania School of Veterinary Medicine, Kennett Square 19348-1692, USA.
Birks
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EK
Uboh
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CE
May
L
L
Teleis
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D
Martini
J
J
D000136:Acid-Base Equilibrium; D000818:Animals; D004232:Diuretics / Q000494:pharmacology*; D005260:Female; D005665:Furosemide / Q000494:pharmacology*; D006470:Hemorrhage / Q000517:prevention & control / Q000662:veterinary; D006734:Horse Diseases / Q000209:etiology / Q000517:prevention & control; D006736:Horses / Q000502:physiology*; D008297:Male; D010805:Physical Conditioning, Animal / Q000009:adverse effects; D011652:Pulmonary Circulation / Q000187:drug effects; D012420:Running; D013177:Sports
D004232:Diuretics; D005665:Furosemide