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Muscle characteristics and plasma lactate and ammonia response after racing in Standardbred trotters: relation to performance
Author(s) -
RONÉUS N.,
ESSÉNGUSTAVSSON B.,
LINDHOLM A.,
PERSSON S.
Publication year - 1999
Publication title -
equine veterinary journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.82
H-Index - 87
eISSN - 2042-3306
pISSN - 0425-1644
DOI - 10.1111/j.2042-3306.1999.tb03811.x
Subject(s) - horse , zoology , chemistry , medicine , blood lactate , ammonia , anaerobic exercise , endocrinology , biology , biochemistry , physical therapy , heart rate , blood pressure , paleontology
Summary Blood samples from the jugular vein and muscle biopsies ( gluteus medius ) In 25 Standardbred trotters were obtained 5–10 min after racing. The biopsies were analysed for fibre type composition and enzymatic profile and blood samples for plasma lactate and ammonia concentrations. Muscle characteristics, plasma lactate and ammonia concentrations after racing were compared with each horse's Individual performance index (IPI). The IPI is calculated annually from the Individual horse's racing performance (% placing 1, 2 or 3, total annual earnings, average earning per start, and best racing record), respectively, converted to and expressed as a percentage deviation from the average record of the same sex and age group. The IPI values were 100–116. Plasma lactate concentrations were 15.0–42.7 mmol/l (mean 31.3 nunol/l) and ammonia concentrations 65–210 μmOl/l (mean 141 μmol/l) after racing. Fibre type composition varied among horses (range 9–27% for type I , 32–54% for Type IIA , and 27–46% for Type IIB ). Fibre type composition, enzyme activities, plasma lactate and ammonia responses to racing were not correlated to IPI, Ten of the horses also performed a submaximal test on the track, consisting of 5 incremental 1000 m heats at approximate speeds of 9.1, 9.5, 10.0, 10.5, and 11.1 m/s. Immediately after each beat a blood sample was drawn from the jugular vein for plasma lactate analysis. Plasma lactate response to exercise differed between horses, but no correlation was seen with IPI. Muscle characteristics, plasma lactate and ammonia concentrations after racing and lactate response to a submaximal track test did not correlate with current race performance expressed as IPI In a group of horses with average or better performance capacity at the time of testing. Analysis of lactate and ammonia in blood after racing is not a valuable tool to predict an individual performance index.