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Preparation of Yearlings for Sale

Preparation of Yearlings for Sale

It could be said that the way yearlings are prepared for sale is a tradition with few questioning the process. Talking with industry stakeholders it would appear that 'we do what we do because that is what we have always done' or simply because 'everyone else does it that way'. For owners and managers willing to take a leap of faith, they will find that there are more economical ways to prepare a yearling for sale that won't cause the health and behaviour problems that current practices may cause.  

WHAT BUYERS WANT ..TO WIN RACES

Purchasing criteria include: 

  • Pedigree 
  • Conformation 
  • Sound X-Ray 
  • Healthy coat 
  • Adequate muscle & topline 
  • Fat cover 
  • Good walk 
  • Temperament 

 Yearling preparation has significant impact on the coat, muscling and fat cover. It can also impact the walk, temperament, conformation and X-Ray results. 

INFLUENCE OF FEEDING MARES DURING PREGNANCY 

How mares are fed and managed during pregnancy has a major impact on the foal, particularly in relation to insulin resistance, trying up, and DOD.  It is now established that if mares are overfed on high NSC feeds during pregnancy, they can suffer gestational diabetes. In turn this can predispose the foal and yearlings to metabolic disorders including insulin resistance. These disorders  are exacerbated if the foal is then fed high grain (high NSC) diets in preparation for yearling sales.  see High-NSC Diets in Pregnant Mares: Risks for Foals and Safer Feeding Alternatives

PRE- PREPARATION 

When bringing yearlings in for sales preparation, sometimes little can be done to rectify historical mismanagement or nutritional problems. It is important however, to recognise that the time leading up to the sales is critical if the purchasers criteria are to be met. 

Conformation and achieving a sound X-Ray 

It is generally considered that the factors that influence conformation are genetics, nutrition and exercise injury. The majority of bone growth occurs from the last trimester through to 12 months of age. Throughout this period it is critical to ensure mares and foals receive proper nutrition. Anecdotally over fat mares are more likely to develop offspring with Development Orthopaedic Disease (DOD) than mares in ideal condition. It is believed that over fat mares predispose to foetal malpositioning that results in congenital flexural deformities and Angular Limb Deformities. It is estimated that 50% of stud farms supply excess energy (high NSC grain) in the diet of young stock which is directly linked to DOD. 

Healthy coat, adequate muscling and fat cover 

Shiny healthy coats and good muscling are something that managers should aim to achieve with all horses throughout their lives. The prime growth period of muscle is from 2 months to 22 months where the muscle fibre size increases up to 70% between 7-18 months. The coat is an indicator of overall health. A natural shiny deep rich coat on an untouched youngster is a clear sign that the horse is doing well with its diet and environment. On the other hand, a coat that lacks lustre or shine, is coarse, long in length or is late to lose the winter coat, can all indicate a nutritional problem. Muscling should always be adequate throughout life. In the diet, protein quality is as important as quantity. If youngsters are losing muscling this should be addressed promptly to avoid any long term consequences. Fat cover will vary in the young horse - periods of higher growth will have a youngster losing fat cover over the ribs. This is followed by a period of slower growth where fat cover will gain over the ribs. Changes to energy content of the diet is generally unnecessary during the growth periods given that during periods of slower growth the fat cover increases so the ribs are covered (it is perfectly acceptable to have the last rib slightly visible). As sales preparation comes closer, increase roughage quality so that fat cover can be optimised 

SALES PREPARATION 

The goal of sales preparation is to show the yearling at its best. This requires sound nutrition and adequate exercise. 

Nutrition 

There are six key nutrients all horses require: 

  • Water 
  • Carbohydrates 
  • Fats & Oils 
  • Protein 
  • Minerals 
  • Vitamins 
Proper Nutrition will achieve: 

  • Correct fat cover 
  • Good muscling and topline 
  • Naturally soft, glossy, rich, shiny coat even before any cosmetic products are applied 
Improper Nutrition can lead to: 

  • Poor muscling and topline 
  • Behavioural problems including difficulty in handling 
  • Typing up resulting in shortened/stiffened gait 
  • Developmental orthopaedic conditions that will be evident on X-Rays. 

FEEDING PROGRAM 

Table 1 illustrates how core ingredients satisfy the (nutrient requirements of) yearlings. Using the correct combination of ingredients will result in a yearling with optimal fat cover, excellent muscling and a rich soft glossy coat. It will also not cause the behavioural and metabolic problems commonly associated with high concentrate intakes. 

For stud managers preparing large numbers of yearlings, it may be beneficial to group like horses together so that the feeding program can be tailored to their needs. This reduces waste and will provide better results. Regular assessment of each yearlings fat cover and adequacy of muscling is required to ensure changes to the ration are made.


Protein quality refers to the amino acid content and suitability for horses. Full fat soybean meal is considered a very high quality (5 star) protein source and also happens to have a high protein content (36%). This is closely followed by lucerne with a content of 19.2% with a good amino acid content (4 star). Whilst grass, cereal grains and sugar beet pulp have reasonable percentages of protein, the quality is lower and supplementation with protein is likely to be required.

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 high NSC grains. 

Overfeeding high NSC feeds to mares and then to foals can cause major metobolic issues including 

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 Mineral Mix is  a specifically designed balanced mineral mix 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 TOPLINE 

Excess energy as NSC in the diet will result in an increase of fat cover. Provide balanced fat, fibre and protein in the form of CoolStance® copra meal and balanced minerals and vitamins (Vitastance® or GroStance®) 

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 NSC 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.

EXERTIONAL RHABDOMYOLYSIS SYNDROME (TYING UP) 

Exertional rhabdomyolysis (ER) is muscle pain and cramping generally associated with exercise. It can be sporadic episodes or chronic where there are repeated episodes. Chronic exertional rhabdomyolysis is described as recurrent exertional rhabdomyolysis (RER), which commonly affects Thoroughbreds, Standardbreds and Arab horses. It also accurs with polysaccharide storage myopathy (PSSM) which predominantly affects Quarter horses but also Paints, Warmbloods, Appaloosas, Morgan horses and draft breeds. Nutritional causes linked to ER include electrolyte imbalances or deficiencies, mineral imbalances or deficiencies, vitamin deficiencies and excess grain, starch or sugar in the diet. Oversupplementation can cause mineral and electrolyte imbalances therefore a broad spectrum macro mineral, trace mineral, electrolyte, vitamin and salt supplement is recommended. Horse owners and trainers of horses that have suffered ER should aim for a 100% roughage diet, if concentrates are required, high fibre and high fat products should be fed in preference to starch or sugar feeds. 

LAMINITIS 

Also known as founder or foot fever, it is an extremely painful and debilitating condition of the hoof. Blood flow in the hoof is compromised leading to breakdown and degeneration of the union between the horny and sensitive layers of the laminae. It is a symptom of a generalised metabolic disturbance and can be classified as acute (very severe), subacute (severe), or chronic (milder signs). Rotation of the pedal bone within the hoof may occur in longstanding chronic cases and can even perforate the sole of the foot. The most common causes are excess carbohydrates (grain overload) or grazing lush pastures. Excess sugars and starches ferment in the hind gut leading to lactic acid buildup killing normal gut bacteria and releasing endotoxins. The endotoxins are absorbed into the bloodstream and travel to the hoof where they interfere with normal blood flow. The blood flow is dramatically reduced with sludging and emboli occuring in the capillaries. The reduced oxygen perfusions means that the hoof wall starts to degenerate and break down, resulting in the clinical signs of laminitis. To prevent grain overload all horses should be fed roughage adlib and minimal concentrates added when required. For horses that are susceptible to pasture induced laminitis, download our laminitis fact sheet from our website. 

COLIC 

Defined as abdominal pain it is the most frequent cause of emergency treatment and death in horses. Risk factors include diet, internal parasitism, medical history, management and weather-related factors. A change in feeding program, amount of concentrate fed, access to pasture, type of forage and water intake are associated with the greatest risk of colic. Horses fed more than 2.5kg of concentrates per day are five times more likely to colic than horses on 100% roughage diets (Tinker et al., 1997) A decrease in pasture availability (either no pasture, reduction in paddock size or reduction in time on pasture) tripled the risk of colic (Hudson et al. 2001). Meal feeding concentrates exaggerates fermentation, resulting in decreased pH and altering fluid balance, resulting in intestinal distention or impaction colic (Clarke et al, 1990). Studies have shown implementing high roughage minimal concentrate feeding programs will reduce the risk of colic. 

Suggested Feeds


Coolstance copra 

  • Low NSC, high DE 
  • Can be fed safely to all horses
  • Does not cause insulin or glucose spikes

Balanced Minerals & Vitamins


References 

Aldred, J. (1998). Developmental orthopaedic disease in horses. Rural ind. Res. Develop. Corp. Publ. 97/79:1-31 

Clarke, L.L., Roberts, M.C, Argenzio, R.A. (1990), Feeding and digestive problems in horses - physiological responses to a concentrated meal. Vet. Clin. North American Equine Practice 6:433 - 450. 

Connysson M., Essen-Gustavsson B., Lindberg J.E., Jansson A. (2010), Effects of feed deprivation on Standardbred horses fed a forage-only diet and a 50:50 forage-oats diet. Equine Veterinary journal, 42: 335-340. 

Ellis J.M., Hollands T., Allen D.E. (2002), Effect of forage intake on bodyweight and performance. Equine veterinary Journal, 34: 66-70. 

Gibbs, P.G, Sigler, S.H., Goehring, T.B. (1989), Influence of diet on growth and development of yearling horses. Journal of Equine Veterinart Science; 9, 215 - 218. 

Glade, M.J., (1983), Nutrition and performance of racing Thoroughbreds. Equine Veterinary Journal, 15: 31-36. 

Glade, M.J., (1989), Effects of specific amino acid supplementation on lactic production by horses exercise on a treadmill. Proc Eleventh Equine Nutr Physiol Symp 1989:244 

Hudson, J.M., Cohen, N.D., Gibbs, P.G., Thompson, J.A., (2001) Feeding practices associated with colic in horses. Journal American Veterinary Medicine Association 219:1414 - 1425 

Hurtig, M., Green, S.L., Dobson, H., Mikuni - Takagaki, Y. and Choi, J. (1993) Correlative study of defective cartilage and bone growth in foals fed a low copper diet. Equine Veterinary Journal Supplements; 16, 66 - 73 

Jansson A., Lindberg J.E. (2012), A forage-only diet alters the metabolic response of horses in training. Animal, 6, pp1939-1946. 

McLean B.M.L. Hyslop J.J., Longland A.C., Cuddeford D., Hollands T. (2000), Physical processing of barley and its effects on intra-caecal fermentation patterns in ponies. Animal Feed Science and Techonology 85, 79-87. 

Meyer, H., (1987), Nutrition and the equine athelete. Equine Exer Physiol 1987;2:644 

NRC (2007), Nutrient Requirements of Horses, Sixth Revised Edition, National Academies Press. 

Savage, C.J., McCarthy, R.N. and Jeffcott, L.B. (1993) Effects of dietary phosphorus and calcium on induction of dyschondroplasia in foals. Equine Veterinary Journal Supplement; 16, 80 - 83 

Tinker, M.K., White, N.A., Lessard, P., Thatcher, C.D., Pelzer, K.D., Davis ,B., Carmel, D.K. (1997) Prospective study of equine colic risk factors. Equine Veterinary Journal 29: 454 - 458 

Vervuert I., Voigt K., Hollands T., Cuddeford D., Coenen M., (2008a), The effect of processing barley on its digestion by horses. The Veterinary Records 162, 984-688

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