Feeding Young Growing Horses to Reduce the Risk of Developmental Orthopedic Disease

Robert Jacobs , Ph.D.

Research Manager, Equine Innovation

Developmental Orthopedic Disease (DOD) is a common concern in young horses. This collective term for a cluster of conditions is typically applied to situations in which skeletal growth occurs abnormally and sub optimally. While nutrition is critical in the proper growth and development of young horses, DOD development is a multi-factorial condition in which genetics and management must be considered. Nutritional mismanagement is a clear contributor to DOD development in horses. However, nutritional optimization is a highly efficacious tool in the prevention of DOD’s or support for those horses already displaying abnormal growth.

Feeding to prevent or limit DOD’s in young horses should follow a few simple guidelines:
  1. Young Horse Feeding Basics
  2. Feeding Young Horses with Developmental Abnormalities
  3. Feeding Young Horses to Support Activity

Young Horse Feeding Basics

Feeding young horses requires careful planning and dietary management long before the birth of the foal. In utero fetal development lays the backbone for the rapid growth that occurs post foaling. Ensuring the mare is receiving optimal nutrition before, during, and after pregnancy will provide the nutrients necessary for fetal development, in addition to the nutritional robustness of the mare’s milk during lactation. Nutritional programs can be designed to support rapid vs. moderate vs. slow rates of growth for young horses, however decisions on growth plans should be made early with few changes occurring during the early growth period. Foals should begin to consume concentrate diets supplemental to those of mare’s milk starting at approximately 28 days of age. It is recommended that foals consume 1 lb of feed per month of age of a diet formulated to meet the nutritional needs of growth. Feeds such as Purina® Ultium® Growth, and Purina® Omolene® 300 have been formulated to meet these specific needs. Feeding with progressive and consistent increases in concentrate amount will allow for the desired steady growth curves associated with optimal skeletal development. Erratic changes to the diet, such as those in which an improper concentrate is fed, free-choice access to concentrate is offered, or sudden changes to concentrate amount occur, can result in similarly unpredictable growth curves that are the hallmarks of DOD development. Young horse diets should include high quality forages that in addition to providing necessary nutrition, also begin and support the maturation of the horse’s hindgut. Testing forages for nutritional content will allow you to understand the nutritional contribution of the forage to the overall diet of the horse.

Feeding Horses with Developmental Abnormalities

Even with optimal nutrition, and more often in cases with sub optimal feeding practices, the development of DOD’s is a common occurrence for young horses. Once a proper diagnosis is confirmed via radiographs or other technique, management changes and nutritional modifications can be critical in supporting the young growing horse’s musculoskeletal development. It is a common misconception that excess calories or protein alone are solely responsible for DOD occurrence. More precisely, imbalances in these and other nutrients have been linked to abnormal growth in young horses. Upon DOD diagnosis, a thorough investigation of the diet should occur. The first thing that should be considered is the overall energy content of the diet. It is likely that an increased energy intake is out of balance with other nutrients and is leading to uneven and rapid growth rate. The goal should be to reduce the energy consumption without reducing or restricting amino acid, vitamin, and mineral intake necessary for optimal growth. Ensuring the horse is consuming a diet balanced in calories and high-quality protein is critical. Crude protein level alone is not indicative of quality. High-quality protein sources such as dried whey, soybean meal, and individual amino acids will provide the optimal amino acid balance necessary for young horse growth.
For some young horses with abnormal musculoskeletal growth due to excess energy intake, feeding the ration balancing feed Purina® Enrich Plus® will supply essential protein, vitamins, and minerals when caloric requirements are met by forage alone (typically restricted to 1.5 – 2% of bodyweight, but can be limited to 1% of bodyweight in severe cases). In cases where forage quality is poor, or complete control of the diet is necessary, a complete feed such as Purina® Equine Junior® can be offered to supply the roughage, calories, and other nutrients required for growth.
Just like the balance between energy and protein in the diet, other nutrients exist in a delicate balance and should be maintained at certain ratios to ensure optimal utilization. Calcium and phosphorus are classic examples of nutrients that should remain balanced to a ratio of no less than 1:1 (2:1 being optimal). Diets with higher amounts of phosphorus than calcium may lead to the development of DOD lesions due to the imbalanced absorption of these minerals in the gut. Copper and zinc are another example of nutrients that should be maintained in a critical balance. The zinc to copper balance should be maintained at a level around 4:1 for the complete diet. Purina feeds formulated to support growth are balanced and contain the optimal levels and sources of these minerals.

Feeding Young Horses to Support Activity

Nutritional requirements of young horses are dictated by a number of factors including age, body size, and energy expenditure, and change continually during the growth period. As the young horse grows, periods of stress linked to weaning and training may exacerbate or ignite DOD related issues. Ensuring the diet of the young horse is nutritionally balanced at all stages of growth will provide the support necessary for the foal to encounter and overcome these stressors. While the nutritional requirements of the foal are greatest at the earliest stages of development, nutritional inputs should match the expected performance outputs. When young horses enter training, it is necessary to reevaluate their nutritional program.


Following basic guidelines for feeding young horses can help to reduce the risk of abnormal musculoskeletal development.
  1. Feeding for growth begins during pregnancy.
  2. Feed a diet designed for growing horses such as Purina® Ultium® Growth or Purina® Omolene® 300
  3. Evaluate all components of the diet including forage
  4. Reduce excess dietary energy in balance with other nutrients, specifically protein
  5. Ensure diets are fortified in the optimal ratios for certain nutrients
  6. Provide a ration balancing feed such as Purina® Enrich Plus® when dietary energy needs are met by forage.
  7. Control the entire diet by providing a complete feed such as Purina® Equine Junior® when forage quality is low or otherwise necessary.
  8. Reevaluate the dietary needs of the growing horse as nutritional requirements change.

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