Muscles In Racehorses

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ANEQ 305 Muscles in Racehorses

There are many ways in which researchers can examine muscles of thoroughbred racehorses. They can look at the amount of, and different types of muscle fibers found in thoroughbreds, the muscles ability to adapt to high intensive exercise, the effects from changing the inclination the horse is exercising on, and if age and gender affect the way the muscles react. The thoroughbred horse stems back to a founder stallion that makes up 95% paternal and 9 to 10 founder mares that can make up 72% of the maternal lineage. The characteristics looked for in good race horses are large lung volume, high hemoglobin concentration, skeletal muscle mass, cardiac output, glycogen storage capacity, and mitochondrial density.
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Muscle fatigue happens whenever a large portion of exercise is involved. Muscle contraction takes a lot of energy to do, using ATP, which can be derived by many sources. Creatine phosphate is the easiest available energy source for muscle fibers to use. Once that energy source is depleted, glycogen is then used through glycolysis or oxidative phosphorylation. If the pace of the exercise the horse is doing can allow the presence of oxygen and aerobic metabolism then the oxidative phosphorylation process will occur. Oxidative phosphorylation is the aerobic process where carbohydrates, fats, and protein are broken down to produce ATP. On the other hand, glycolysis is an anaerobic process which means it does not use oxygen. This process converts glucose into pyruvate, then converted into acetyl CoA or lactate. If oxygen is not present or a very small amount, the lactic acid cycle begins and three molecules of ATP are produced. The end to this process causes soreness and fatigue. Heat dissipation is where the muscles generate thermal energy and need to release it. Half of the horse’s body is made up of muscle tissue. If the muscle is large, then only a small amount of it will be exposed to the surface which will increase the difficulty of dissipating the heat. Just like humans, horses dissipate heat through perspiration aka sweat. Horses can also relieve heat …show more content…
In one study, three males and two female thoroughbred racehorses were tested and compared to four males and one female riding horses. The racehorses averaged the age of five and the regular riding horses averaged the age of thirteen. The researchers examined the plasma malate, M/L ratio, and lactate dehydrogenase activities to figure out the energy metabolism in the horses. Plasma malate is incorporated in the ATP and NADH generation, but lactate dehydrogenase can convert NADH to NAD+ for the making of ATP. The increase of plasma M/L ratio can show a heightened metabolism energy in the skeletal muscle and liver of the horse when adapted to continuous and intensive training. Plasma lipid metabolism analytes can reflect changes to the rate of lipolysis which also can indicate the change in energy metabolism. The results showed that racehorses increased the plasma malate and lactate dehydrogenase activity. The plasma M/L ratio in the racehorse was twice as high as that of the regular riding horses. The racehorses also demonstrated a higher level of plasma lipid metabolism analytes. To conclude the study, the racehorse muscles adapted to the longer high intensity exercise by gaining an increased capacity for fat utilization as energy source and a higher oxidative capacity resulting in higher energy metabolism and an increased rate of lipid mobilization. Conventional

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