FACTORS INFLUENCING PERFORMANCE OF THE HORSES

November 14, 2020

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Horses are not reared speciallyto produce meat or milk. Instead, they are raised to be athletes, with work as their main productive function.
There are different types of work that horses can perform, based on which they are classified into different categories such as light, moderate, heavy and very heavy work.
Energy generation during exercise:
Conversion of chemically bound energy from feed into mechanical energy for muscular movement.
Intramuscular glycogen and triglycerides and extra muscular stores such as adipose tissue and liver glycogen.
Since, horses do not eat continuously while they exercise, the energy must be stored in the horse’s body for later release.
Work capacity depends on the rate at which energy is supplied to and used by muscles for contraction.
The most direct way to form ATP is by the cleavage of another compound, creatine phosphate (CP). However, since muscle contains only small amounts of CP and ATP, the supplies are exhausted after a short duration of exercise.
Prolonged exercise would not be possible without a way for ATP to be resynthesized at the same rate at which it is used. Two fundamental reactions resynthesize ATP:

Oxidative phosphorylation breaks down carbohydrates, fats, and protein into energy (ATP) with the involvement of oxygen. The use of oxygen qualifies this as an aerobic reaction.
Glycolysis breaks down glucose or glycogen into lactic acid. This reaction doesn’t use oxygen and is considered anaerobic.

Involvement of the muscle fibers:
The horse has three basic types of muscle fiber: I, IIA, and IIB. These fiber types have different contractile and metabolic characteristics.
Type I fibers: slow-contracting fibers
Types IIA and IIB:fast-contracting
Type I and IIA fibers: have a high oxidative capacity and can thus utilize fuels aerobically
Type IIB fibers: have a low aerobic capacity and tend to depend on anaerobic glycolysis for energy generation.

The different factors or the chock points limiting the performance of the horses can be divided into following categories which includes:

Heart rate (HR) x stroke volume

HR in resting horses = 25-45 beats per minute and averages around 32-35.
Maximal HRs of 220-250 beats per minute. SV = 0.8 – 1.2 litres per beat.
At maximal exercise, CO can reach over 250 lit. per minute. This massive CO is one reason that horses are such good natural athletes.
Role of RBCs’:
Since oxygen is carried by the red blood cells, the number of these cells can affect the performance
They have the ability to store as many as half of these cells in their spleen when they are not exercising
When strenuous exercise begins, these cells are mobilized into the blood stream where they double the oxygen carrying capacity of the blood. A deficiency of red blood cells (anaemia) could possibly limit performance, but this usually only happens when the horse has suffered some type of infection or illness.
Respiratory system:
Most of the horses have a partial paralysis of the muscles in the larynx which ultimately reduces the size of the wind pipe. This is called roaring in later stages due to the noise made by the horse during exercise.
Chronic Obstructive Pulmonary Disease (COPD) or heaves: affected horses may cough, develop a nasal discharge and have excessive tearing of the eyes. Respiratory rate is increased, and lung elasticity is diminished.
Exercise Induced Pulmonary Haemorrhage (EIPH) or bleeding: Horses with EIPH bleed from the lungs during intense exercise which greatly reduces the efficiency of transfer to oxygen into the blood stream.

Conformation and Biomechanics:
Incorrect conformation: horses with this are likely to be unsound. Lameness is the key factor limiting performance in all types of horses.
A second type of conformation defect makes the horses the poor movers since they have to expend extra energy while working. Such horses may not be useful for the race purposes as they must work much harder to do the same amount of work and therefore they get fatigued earlier than more biomechanically correct individuals.
Since stride frequency is dependent on the respiratory rate, these horses with the short strides have higher respiratory rates with reduced oxygen transfer in the lungs. This greatly reduces their aerobic capacity.

Dr.Akshay J. Wankhade

M.V.Sc (Animal Nutrition)

Fine Organics Industries Limited

8657580179

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