Postprandial arterial vasodilation in the equine distal thoracic limb.

This research study explores how feeding affects the blood flow to a horse’s foot, particularly focusing on the postprandial (after eating) response. Using advanced imaging methods, the researchers found that feeding leads to an increase in the blood flow to the horse’s foot without any changes in heart rate or blood pressure.

Research Methodology

• The study was conducted in a temperature-controlled room and employed duplex Doppler ultrasonographic technology to observe the lateral proper palmar digital artery of five horses both before and after they ate.
• The horses were randomly subjected to two different feeding regimes – twice a day and four times a day – in an unbalanced 2 period crossover design. This means that the horses were not evenly assigned to the feeding regimes, but were switched between them over two different periods.
• Over a 4-hour period, the researchers collected data on several factors, including arterial diameter, blood velocity, heart rate, blood pressure, total plasma protein, packed cell volume, and plasma glucose and insulin levels.

Findings

• The feeding regimen had no significant impact on the variables being measured, indicating that the frequency of feeding does not affect blood flow to the horse’s foot.
• Postprandial observations showed significant increases in arterial diameter, blood velocity, total plasma protein, plasma glucose, and insulin levels.
• Contrarily, heart rate, blood pressure, and packed cell volume did not show significant changes after feeding, suggesting that the increase in blood flow to the foot is not associated with general circulatory or volumetric changes.

Significance

• The research revealed that normal postprandial response in horses involves an increase in blood flow to the foot. This is potentially crucial information for understanding equine health and behavior, particularly in relation to feeding habits.
• The study also affirmed the value of using ultrasonography as a noninvasive tool for studying vascular changes in conscious horses. Thus, demonstrating the technique’s potential usefulness in diagnosing vascular diseases in horses in the future.