Effects of training distance on feed intake, growth, body condition and muscle glycogen content in young Standardbred horses fed a forage-only diet.

This research examines how specific training programs and a forage-only diet impact aspects of health and performance in young Standardbred horses. The findings suggest neither intense training nor the type of diet have a significant effect on the horses’ feed intake, growth, body condition or muscle glycogen content.

Experiment setup and methodology

• The study involved 16 Standardbred horses being fed a high-energy, forage-only diet. They were divided into two groups – one followed a standard (control) training programme (C-group), and the other followed the same program but with high-intensity training distance reduced by 30% (R-group).
• The horses were subjected to these conditions from January as 2-year olds until December as 3-year olds.
• Feed intake was recorded 10 times across three consecutive days at regular intervals. Other measurements such as body weight, height, body condition score (BCS), rump fat thickness, and thickness of the m. longissimus dorsi were taken every seven weeks throughout the study.
• At the beginning and end of the study, muscle samples were taken from the horses and analysed to measure glycogen content. Any nutrition-related health issues or stereotypic behaviours were noted as they arose.

Key findings

• The horses consumed between 1.7% to 2.6% of their body weight in dry matter, equating to 19 to 28 MJ metabolisable energy/100 kg body weight.
• Neither training group showed any differences in feed intake or body measurements.
• Body condition scores were maintained between 4.8 and 5.1 throughout the study. Muscle glycogen content was consistent at 587 and 623 mmol/kg dry weight for 2- and 3-year olds respectively, with no significant difference between training groups.
• Under these specified conditions, none of the horses developed nutrition-related health disorders or stereotypic behaviours.

Conclusion

The study concludes that the training regimen did not impact feed intake, growth, body condition score, or muscle glycogen content. The forage-only diet also did not limit muscle glycogen storage, growth, or maintenance of body condition. Instead, it seemed to foster good nutrition-related health. Thus, this research implies that an intense training program and a forage-only diet may be suitable for maintaining good health and performance in young Standardbred horses.