Clinical pathologic alterations in horses during a water deprivation test.

The research paper examines the impact of a 72 hour water deprivation test on 12 horses, in particular, the clinical pathologic changes and changes in electrolyte clearance. The study also compares different measurement techniques for urine concentration and the influence of water deprivation on serum and urine electrolyte concentrations and acid-base values.

Experimental Approach

• The research team carried out a 72-hour water deprivation test on 12 horses to study the clinical pathologic changes induced by such stress.
• The team turned their attention to the critical values for electrolyte (X) clearance, expressed as a fraction of creatinine clearance (CLCR; %CLCRX).
• Two different techniques for measuring urine concentration were compared: osmometry and refractometry.

Key Findings

• Before the water deprivation, the researchers noted specific baseline values for %CLCRX determination in the animals.
• Throughout the water deprivation period, individual variations for electrolyte clearances were observed. Importantly, sodium (Na) excretion increased considerably after 24 and 48 hours.
• After 48 hours of water deprivation, %CLCRNa decreased significantly. Despite this, it was still higher than the initial clearance.
• The research revealed that plasma protein served as a more accurate indicator of water deprivation (or dehydration) than Packed Cell Volume (PCV) in horses.
• The team also recorded the electrolyte concentrations in the serum and urine of the animals. They found minimal significant change in acid-base values after 72 hours’ water deprivation.
• In terms of measuring urine concentration, specific gravity (sp gr) initially correlated well with urine osmolality determinations. However, this correlation started to diminish after 48 hours.

Implications

• This research provides vital insights into the physiological changes horses undergo during periods of water deprivation. This will help in monitoring and managing horses under such conditions.
• The study’s outcomes also highlight the effectiveness of different markers (plasma protein versus PCV) in determining dehydration levels.
• The comparison of urine concentration methods also provides a practical input into the selection of suitable diagnostic tools in related studies or diagnoses.