Long-term adaptation capacity of ponies: effect of season and feed restriction on blood and physiological parameters.

The research investigates the adaptive capacity of Shetland ponies kept in semi-natural environments over a year, focusing on the effect of seasonal changes and food supply reduction on various health parameters. The key findings suggest that these ponies can cope well with environmental variations provided there is sufficient food supply.

Study Design and Methodology

• The study involved 10 Shetland pony mares that were kept under semi-extensive conditions for a period of one year.
• Different parameters – physiological and blood – were recorded at regular intervals. Physiological indications were measured every two weeks, and included body weight (BW), body condition score, cresty neck score, and resting heart rate.
• Blood parameters were tracked monthly, and they encompassed Triiodothyronine, thyroxine, non-esterified fatty acids (NEFA), total bilirubin, total protein, triglycerides, glucose, insulin, and hair length.
• In winter, these ponies were divided into two feeding groups, one receiving 60% and the other 100% of the maintenance energy requirement.

Findings

• The study found that seasonal change, particularly from summer to winter, led to a reduction in resting heart rate.
• Refeeding of feed-restricted ponies resulted in a quick boost in resting heart rate and body weight. Also, blood parameters went back to their reference levels.
• A significant insight was that the ponies that received adequate supplies adapted smoothly to varying environmental conditions.

Effects of Feed Restriction

• The study showed that feed restriction during winter in ponies led to reduced resting heart rates suggesting a drop in basal metabolic rate.
• The energy restriction was compensated by the ponies through the mobilization of body fat reserves, leading to alterations in blood parameters.

Implications and Suggestions

• This research suggests that Shetland ponies can be managed year-round in outdoor housing systems if the supply of food is adequate to meet their maintenance energy requirements.
• The rapid restoration of physiological and blood factors after refeeding in feed-restricted ponies also suggests their high resilience and adaptability.