The development and growth of the foal and young horse have a significant influence on the performance of the horse in adulthood. The primary factor influencing physical development is the horse's genetic makeup. However, nutrients supplied through the diet also play an important role in growth and development 1. A balanced diet supports healthy growth and development and helps prevent orthopaedic disorders caused by deficiencies or excesses of nutrients, thereby contributing to the horse's overall welfare 2.
During the first months of life, the foal obtains the nutrients it requires from the mare's milk. The first feed the foal receives after birth is the mare's colostrum. Colostrum provides energy, essential nutrients, and immune components that are crucial for the development of the foal's immune system and its protection against potential pathogens 3. It is important that the foal consumes colostrum as soon as possible after birth because its metabolic rate is high, while it has no body reserves to provide energy 4. In addition, the period during which the mare produces colostrum is short, and its composition changes within 12 hours after foaling 3.
During the first 30 days after birth, foals gain approximately 1.3–1.5 kg of body weight per day 5. Dietary energy is essential for maintaining body functions and body weight, while also supporting growth 6. Amino acids derived from dietary protein are the primary building blocks required for the foal's growth and development 6. Proteins, for example, are essential for collagen synthesis, an important component of joint development, as well as for enzymes involved in the formation and development of body tissues 6. The minerals and trace elements calcium, phosphorus, copper, zinc, and manganese, together with vitamins A, D and E, are particularly important for the healthy development of bones and joints 6.
By approximately two months of age, the mare's milk alone no longer meets the foal's nutritional and energy requirements. Studies have shown that around this age forage intake increases while milk intake declines 7. As a result, the intestinal microbiota becomes capable of fermenting fibre from forage into volatile fatty acids, which provide an important source of energy for the body 7,8.
To ensure an adequate intake of protein, energy, vitamins and minerals, the diet can be supplemented with a specially formulated foal concentrate, designed to support healthy growth and development. In addition, it is important that the foal has continuous access to sufficient high-quality forage 9.
Concentrate feed should be introduced gradually to avoid excessively rapid growth rates 3. Providing excessive amounts of concentrate too quickly, resulting in dietary energy and protein intake exceeding the foal's requirements, may lead to rapid growth spurts that can adversely affect skeletal development and increase the risk of developmental orthopaedic diseases 3,10. Conversely, deficiencies in essential nutrients can also impair normal growth and development 3. It is therefore recommended that the foal's Body Condition Score (BCS) is assessed regularly. The BCS can be used as a practical tool to monitor the adequacy of dietary energy intake, allowing the ration to be adjusted where there is an excess or deficiency of dietary energy 3.
At approximately six months of age, the foal can be weaned from the mare. As weaning can be a stressful period, it is important to monitor both body weight and growth. Stress associated with weaning may result in excessive weight loss, which can negatively affect growth 6. Research has shown that introducing both concentrate feed and forage before weaning reduces stress during the weaning process 11. Reduced stress, together with prior familiarity with the post-weaning diet, helps minimise weight loss. Following weaning, the foal's diet should consist of high-quality forage and concentrate feed to provide the nutrients required for continued growth and development 12.
Horses generally reach their mature size between five and seven years of age. Nutrition has the greatest influence on growth and development during the first two years of life 6. It is therefore important to regularly assess whether the nutrient requirements of the young horse are being met by the diet provided. Where discrepancies exist, the ration should be adjusted to meet the horse's individual nutritional requirements. In summary, a well-balanced diet that supports the growth and development of the foal optimises both the welfare and the future performance of the adult horse.
References
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- Glade, M. J., & Belling, T. H. (1984). Growth plate cartilage metabolism, morphology and biochemical composition in over- and underfed horses. Growth, 48(4): 473-482.
- Becvarova, I., & Buechner-Maxwell, V. (2012). Feeding the foal for immediate and long-term health. Equine Veterinary Journal, 44(41): 149-156.
- Kinsella, H. M., Hostnik, L. D., & Toribio, R. E. (2022). Energy endocrine physiology, pathophysiology, and nutrition of the foal. Journal of the American Veterinary Medical Association, 260(3): 83-93.
- Buechner-Maxwell, V. A. (2005). Nutritional support for neonatal foals. Veterinary Clinics of North America - Equine Practice, 21(2): 487-510.
- Staniar, W. B. (2013). Chapter 12 - Feeding the growing horse. In Geor, R.J., Harris, P.A., & Coenen, M., (Eds.). Equine Applied and Clinical Nutrition. Saunders Elsevier: China.
- Crowell-Davis, S. L., Houpt, K. A., & Carnevale, J. (1985). Feeding and drinking behavior of mares and foals with free access to pasture and water. Journal of Animal Science, 60(4): 883-889.
- Faubladier, C., Julliand, V., Danel, J., & Philippeau, C. (2013). Bacterial carbohydrate-degrading capacity in foal faeces: Changes from birth to pre-weaning and the impact of maternal supplementation with fermented feed products. British Journal of Nutrition, 110(6): 1040-1052.
- Grace, N. D., Pearce, S. G., Firth, E. C., & Fennessy, P. F. (1999). Concentrations of macro- and micro-elements in the milk of pasture-fed Thoroughbred mares. Australian Veterinary Journal, 77(3): 177-180
- Staniar, W. B. (2010). Linking dietary energy and skeletal development in the horse. Revista Brasileira de Zootecnia, 39: 138-144.
- Hoffman, R. M., Kronfeld, D. S., Holland, J. L., & Greiwe-Crandell, K. M. (1995). Preweaning diet and stall weaning method influences on stress response in foals. Journal of Animal Science, 73(10): 2922-2930.
- Ralston, S. L. (1997). Feeding the rapidly growing foal. Journal of Equine Veterinary Science, 17(12): 634-636.