Roughage

Roughage in the form of grass or hay should form the basis of all horses diets – including performance horses and horses undergoing yearling preparation. Adlib roughage will ensure a healthy digestive system is maintained and will provide the majority of energy in the diet.

Energy Concentrates

Energy concentrates are required when horses need additional fat cover. Sources of concentrated energy include cereal grains, sugar beet pulp and oil. Oil and sugar beet pulp

are considered very safe energy concentrates that will assist with fat cover without causing the digestive disturbance and behavioural problems associated with grains.

Protein Concentrates

Protein concentrates are recommended for all horses up to the age of three. Anecdotally, excess protein has been associated with behavioural problems. Other disadvantages of excess protein are reduced performance in racehorses and an unnecessarily expensive feed bill. Inadequate quantity or quality of protein results in poor muscling and topline.

Minerals & Vitamins

Equilibrium products are specifically designed to be incorporated into the diet to complement the energy and protein content. Energy and protein concentrate requirements will vary depending on the quality of roughage. Incorporating minerals and vitamins into a concentrate ration means that adjustments to energy intake will change the mineral, vitamin and protein intake. Similarly to make adjustments to the protein intake, it will make changes to the mineral, vitamin and energy intake. Separating energy, protein, minerals and vitamins sources reduces waste and ensures each horse is receiving the optimal ration.

Achieving optimal fat cover

Excess energy in the diet will result in an increase of fat cover. Energy is supplied in the form of carbohydrates or oil. Figure 1 shows the order in which each energy source should be added in the diet.

Achieving adequate muscling

Protein quality and quantity both affect the ability of horses to build adequate muscles. Excess protein will not achieve any further muscle gains and is an expensive way for horses to accumulate additional fat stores. Figure 2 shows the order each protein source should be added to the diet in order to achieve appropriate muscling.

Get the coat gleaming

You may be surprised to learn that Equilibrium supplements are the secret ingredient for many highly successful show horses in Australia, New Zealand, UK & Europe. Whilst Equilibrium supplements are broad spectrum supplements designed to top up and rebalance the diet, in the showing world it is valued for its ability to bring out a brilliant, deep, shiny coat all year.

Keeping them sound and calm

The Equilibrium feeding program works to ensure that the common negative side effects of traditional yearling preparation don’t occur. Feeding high starch and sugar feeds cause digestive disturbances which may result in horses tying up, showing behavioural problems and predisposes to DOD. The Equilibrium feeding program works to keep these levels low and well within what current research deems are safe levels.

Management

In the ideal world yearlings would be prepared in a social paddock environment where they can graze, play and self exercise all day. A natural approach would alleviate many of the problems associated with intensive sales preparation.

In researching this topic the most concerning comment we came across was that fillies required more exercise than colts because they gained weight easier and required more exercise to keep their weight from ballooning. The reason we highlight this comment in particular was that excessive or inappropriate exercise can worsen existing DOD problems or create new problems that will be evident on X-Rays. The first step in reducing fat cover should always be to reduce or eliminate energy concentrates, then reduce roughage quality. The goal is for yearlings coming into sales preparation to have good muscling. Yearlings with poor muscling are indicating a protein deficiency in the diet or an underlying health issue.

Loss of income and medical expenses

Poor nutrition and management costs Australian studs millions of dollars a year in lost income and veterinary expenses.

Developmental Orthopedic Disease (DOD)

Musculoskeletal abnormalities include:

• Angular Limb Deformities (ALD, Crooked Legged Foals)
• Physitis
• Subchondral Bone Cysts
• Osteochondrosis (OC)
• Flexural Limb Deformities (Contracted Tendons excluding congenital contracted tendons)

80% of Thoroughbred foals born in Australia have some degree of ALD (Aldred, 1998). Management of the diet and husbandry of the foal can exacerbate the development of osteochondral problems. Factors that contribute to bone growth disorders include genetics, trauma, pre and postnatal nutrition.

Osteochondrosis (OC) is the failure of or abnormal cartilage maturation.

Osteochondrosis dissecans (OCD) is when abnormalities of joint cartilage and subcondral bone has progressed to cracks and fissures in the cartilage. OCD is more advanced than that seen in OC.

Physitis (Epiphysitis) is inflammation of the physis, or metaphyseal growth plate. It is generally considered to be a manifestation of OCD although it is believed that it can result from excessive exercise, excessive weight or poor conformation placing stress on the immature bone.

Angular Limb Deformities (ALD) exists when the limb deviates axially from the normal vertical plane. Congenital ALD are present at birth and are generally believed to be as a result of malpositioning of the uterus, joint laxity or incomplete ossification of the small bones in the knee or hock (commonly found in premature foals). Acquired ALD are apparent within the first few months of life and can result from OCD in the physis causing asymmetric growth, the result of trauma or uneven weight distribution across the joint.

Flexural Deformities result in the inability to straighten or extend the leg with a knuckled over or upright appearance to the limb. Causes include infections or toxins during development of the embryo, positioning of uterus, genetic factors, pain resulting from physitis, OCD or other injuries or a difference in bone growth and tendon development.

Subchondral Cystic Lesions is a cyst like structure in subchondral bone. Lesions can be secondary to OCD or the result of trauma to weight bearing joint surfaces.

Cuboidal Bone Malformation occurs when there is a delay in the endochondral ossification of the cuboidal bones in the knee. Causes include prematurity, hypothyroidism or variations in normal rate of ossification. Generally presents shortly after birth as bones collapse under weightbearing stress.

Causes of DOD include trauma, rapid growth rates, large body size, hormonal aberrations, genetic predisposition and incorrect nutrition.

Nutrition is considered one of the major causes of DOD and includes:

• Excess energy intake
• Inadequate protein
• Calcium and Phosphorus imbalance
• Inadequate trace minerals

Excess energy intake, particularly in the form of soluble carbohydrates will consistently produce lesions of OCD (Aldred, 1998). A study showed horses fed 29% more energy then recommended by the National Research Council (NRC) resulted in 11 out of 12 foals with numerous OCD lesions with only 1 of 12 foals on a diet consistent with NRC recommendations showing OCD lesions. The foals on the high energy diet had more lesions with greater severity then the one foal on the NRC diet. Overfeeding a pregnant broodmare may also effect the incidence of DOD in her foals. Anecdotally, overfat mares are more likely to have offspring develop DOD then mares in optimum condition. Overfat mares may predispose to foetal malpositioning that results in congenital flexural deformities and ALD.

Protein deficiency combined with an adequate energy intake may cause reduced bone growth without affecting weight gain, and this may predispose to DOD (Gibbs et all 1989).

A Calcium and Phosphorus imbalance can cause DOD and both are required for normal bone development. A deficiency or imbalance causes impaired endochondral ossification, decreased bone mineralisation and results in a wide range of problems including lameness, decreased bone density, fractures and DOD. The calcium to phosphorus ratio should be maintained between 1.1:1 to 2:1. An inverted ratio (calcium less than phosphorus) results in nutritional hyperparathyroidism also known as bighead or bran disease. Experimentally a diet with a calcium to phosphorus ratio of 1: 2.1 has shown to cause DOD with 5 out of 6 foals developing multiple OCD lesions (Savage et al 1993).

Copper deficiency has been linked to stud farms with high incidences of OCD (Gabel et al 1987). Experimentally low copper diets have shown to increase rate of OCD, physitis, ALD and flexural deformities (Hurtig et al 1993).

Zinc deficiency in an unpublished study in the USA found foals fed 152ppm of zinc had less cartilage defects than those fed 42ppm. Further research is required to confirm this finding.