Growth, training response and health in Standardbred yearlings fed a forage-only diet.

The study examines the impacts of a forage-only diet and regular training regimen on young Standardbred horses, demonstrating that the horses can meet usual growth and training targets, whilst maintaining good health.

Introduction and Purpose of Study

• The aim of this research was to study the impact of an exclusively forage-based diet and a conventional training program on young Standardbred horses over a period of four months.
• The intent was to compare the findings with similar research on the feeding and training of these animals.

Methodology

• Sixteen Standardbred colts were selected for the experiment, all of which were fed strictly a forage diet from breaking stage (August to December).
• The diet was composed of grass haylage, lucerne and minerals. The horses’ body development and feed intake were monitored monthly.
• The horses were trained with the goal of being able to trot vigorously for distances ranging from 5 to 7 km at speeds of 5.6 m/s. The amount and frequency of training were documented daily.
• The researchers measured the horses’ heart rate during and after a standard exercise test and collected a post-exercise blood sample to test for lactate concentration in plasma.
• Muscle biopsies were taken from the gluteus medius muscle and analyzed for glycogen and fiber composition.
• Health was evaluated in October and November by an independent veterinarian using a standard health scoring protocol.

Findings

• On average, body weight and height at the withers (shoulder blades) increased and body condition score was found to be acceptable.
• Muscle glycogen content was within expected range, indicating sufficient energy levels to perform physical activity.
• A significant decrease in post-exercise heart rate was noticed, and there was a negative correlation between the amount of individual training and heart rate during and after the exercise. This indicates that heart rate decreased with increased training intensity, showing improved fitness and stamina over time.
• Health scores were high and stable throughout both assessments, and the number of lost training days per month due to health issues was less than 0.9, excepting November.

Conclusions

• The study concluded that young Standardbred horses on an unrestricted high-energy forage diet can keep up with standard training objectives and demonstrate growth rates comparable to other light breeds of horses on different diets.
• This indicates a forage-only diet does not inhibit optimum growth or performance in Standardbred yearlings and may be a viable approach, taking the holistic health and development of the animals into consideration.