Physiologic alterations in the horse produced by food and water deprivation during periods of high environmental temperatures.

This research investigated the physiological effects of 72 hours of food and water deprivation on horses during high temperature conditions, revealing significant weight loss and changes in blood properties.

Research Methodology

• This study involved eight healthy horses. These horses were exposed to a period of high environmental temperature but were not given food or water for a duration of 72 hours.
• The horses’ physiological changes were monitored during this time, with a focus on weight, extracellular fluid volume, and plasma volume. These were compared to their baseline values measured at the start of the experiment.
• The study also observed changes in certain blood parameters, including plasma protein, sodium, chloride, osmolality (a measure of the concentration of all the particles found in one kilogram of fluid), packed cell volume, and levels of various minerals like potassium, calcium, magnesium, and phosphate.

Key Findings

• During the 72 hours of deprivation, each horse lost an average of 51.6 kg, equal to about 10.7% of their body weight.
• Significant decreases in extracellular fluid volume (by an average 18.6 liters) and plasma volume (by an average 5 liters) were observed.
• Levels of plasma protein, sodium, chloride, and osmolality increased as a response to dehydration.
• The lack of food and water did not significantly affect the packed cell volume and levels of plasma potassium, calcium, magnesium, and phosphate.
• The dehydration and clinicopathologic modifications observed in the horses were similar to those seen in other species facing a water deficit.

Recovery Post Deprivation

• After 72 hours, the horses were given access to water only, without food. It was observed that within the first hour, they were able to regain about 62% of the lost weight.
• The return to their baseline weight indicates the horses’ ability to recover from the effects of water and food deprivation once these resources are made available again.