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Growth, training response and health in Standardbred yearlings fed a forage-only diet
S Ringmark1, L Roepstorff, B Essén-Gustavsson
1Department of Animal Nutrition and Management, Swedish University of Agricultural Sciences, Sweden.
Insights
Young Standardbred horses on a forage-only diet met training goals and grew well. This feeding system supports athletic development and growth in yearlings.
Area of Science:
- Equine Nutrition and Exercise Physiology
- Animal Science
- Veterinary Sports Medicine
Background:
- Evaluating alternative feeding strategies for young athletic horses is crucial for optimizing performance and health.
- A forage-only diet is proposed as a potentially beneficial system for young Standardbreds in training.
- Understanding the physiological and developmental effects of such a diet is essential for equine sports science.
Purpose of the Study:
- To holistically describe the effects of a forage-only feeding system combined with conventional training on young Standardbred horses.
- To compare the obtained data with existing literature on young horse development and training.
Main Methods:
- Sixteen Standardbred colts were fed a forage-only diet (grass haylage ad libitum, lucerne product, minerals) for four months during training.
- Training intensity, feed intake, body development, heart rate (HR) during exercise, and muscle glycogen were monitored.
- Health assessments and post-exercise blood lactate were also analyzed.
Main Results:
- Horses showed significant increases in body weight and height, with a body condition score of 4.9.
- Post-exercise heart rate decreased significantly, and training volume correlated negatively with HR.
- Muscle glycogen levels were high (532 mmol/kg dry weight), and health scores remained consistently high, with minimal lost training days.
Conclusions:
- Yearlings in training can achieve conventional training goals and exhibit optimal growth on a high-energy forage-only diet.
- This feeding system appears to support athletic development and physiological adaptation in young Standardbreds.
- The findings suggest that a forage-only approach is a viable option for feeding young horses in training.
Abstract:
The aim of this study was to, from a holistic perspective, describe the effects of a forage-only feeding system and a conventional training program on young Standardbred horses and compare data with similar observations from the literature. Sixteen Standardbred colts fed a forage-only diet for 4 months from breaking (August to December) and with the goal to vigorously trot 5 to 7 km at a speed of 5.6 m/s (3 min/km) were studied. The horses were fed grass haylage (56 to 61% dry matter (DM), 2.80 to 3.02 Mcal DE/kg DM and 130 to 152 g CP/kg DM) ad libitum, 1 kg of a lucerne product and minerals. The amount of training and number of training sessions were documented daily, and feed intake and body development were measured once every month. Heart rate (HR) was measured during and after a standardized exercise test in October and December. In December, a postexercise venous blood sample was collected and analyzed for plasma lactate concentration. Muscle biopsies (m. gluteus medius) were taken and analyzed for glycogen and fiber composition. Health was assessed in October and November by an independent veterinarian using a standardized health scoring protocol. BW and height at withers increased from 402 to 453 kg (root mean square error (RMSE) 6) and from 148.7 to 154.1 cm (RMSE 0.7), respectively, and the body condition score was 4.9 (RMSE 0.2) at the end of the study. Muscle glycogen content was 532 mmol/kg dry weight (s.d. 56). There was a significant decrease in postexercise HR (81 v. 73 bpm, RMSE 8), and the individual amount of training was negatively correlated with HR during and after exercise. Health scores were high and similar at both assessments (8.4 and 8.4 (RMSE 1.0) out of 10; P > 0.05), and the number of lost training days per month due to health problems was <0.9, with the exception of November (5.3 days). It is concluded that yearlings in training fed high-energy forage ad libitum can reach a conventional training goal and grow at least as well as earlier observations on yearlings of other light breeds.
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