Effect of long-term feed restriction on the health status and welfare of a robust horse breed, the Shetland pony (Equus ferus caballus).

The study examines the effects of long-term feed restriction on the health and welfare of Shetland ponies, which are a robust horse breed, during winter conditions. The findings suggest that while reduced feed intake leads to significant weight loss and changes in blood parameters, it doesn’t affect certain other aspects such as thyroxine levels, indicating that Shetland ponies can adapt to living in outdoor group housing with additional feed supply all year round.

Introduction and Objectives

• The paper looks into the impact of potential feed shortage during winter in semi-natural horse keeping systems on the health and welfare of horses, using test subject Shetland ponies. Shetland ponies are known for their hardiness and resilience.
• The researchers monitored several aspects of the ponies’ health and body condition for a duration of seven months, including tracking changes during a four-month period of reduced feed intake.

Methodology

• Ten female Shetland ponies were included in the study.
• Various health parameters were monitored including body mass, body condition score, and blood concentrations of key indicators such as NEFA (non-esterified fatty acids), total protein, total bilirubin, beta-hydroxybutyrate, and thyroxine.
• Five of the ponies received a restricted feed intake during the four-month period of the trial.

Results

• The result showed that restrictively fed animals lost nearly 18.4% of their original body mass and their body condition score decreased significantly.
• There was an observed increase in total bilirubin and NEFA concentrations in restrictively fed horses compared to control ponies. These increased levels suggest that fat was being mobilized in the ponies due to undernourishment.
• The restrictively fed group also showed variation in total protein and beta-hydroxybutyrate values towards the end of the trial.
• The study interestingly noted that the feed restriction had no impact on thyroxine concentrations.

Conclusions

• The study indicates that the body condition score as well as plasma NEFA and total bilirubin concentrations are good indicators for detecting health issues caused by malnourishment in horses living in semi-natural conditions.
• The observed increased NEFA concentrations suggest that fat was mobilized in the ponies due to undernourishment.
• It concludes that a year round outdoor housing with additional feed supply is a suitable housing system for a resilient horse breed like the Shetland pony, as unlike the restrictively fed ponies, the control animals maintained blood parameters within the reference ranges.