TDK conference 2020

Developmental Orthopedic Disease (DOD) is a term used to describe a group of diseases that affect the skeleton of growing horses. These include physitis, angular limb deformities (ALD), flexural limb deformities (FLD), tarsal bone collapse, osteochondrosis (OC), subchondral cystic lesion (SCL), juvenile osteoarthritis and cervical vertebral malformation. All of the mentioned diseases are caused by disturbances in the process of endochondral ossification. Common clinical signs include enlarged growth plates, stiffness of the affected joint, lameness and reduced activity. DOD causes huge economical losses worldwide: in Kentucky it has a 10% prevalence, while Lepuele reported 46% in France. Due to the clinical signs there is serious reduction in the price and future performance of the growing horse. DOD has a complex, multifactorial aetiology, the most important factors are nutrition, rapid growth, biomechanical stress and trauma, hormonal factors and genetical predisposition. Nowadays the proper nutrition of pregnant mares and their foals is thought to be the most important factor in the prevention of DOD. During the evaluation of a correct diet plan we must pay attention to the energy intake, the source of energy, the protein/energy ratio, and the ratio and requirements of calcium, phosphorus, copper, and zinc.

In our research we examined 46 foals of a Hungarian stud farm and their feeds’ nutritional values in 2019. We started with the body condition scoring (BCS) of pregnant mares in the last trimester of pregnancy. After parturition we measured the foals’ wither heights and bodyweights in every 1-2 months until weaning. During the measurements we noted the presence of any possible DOD lesions. We calculated the foals’ average daily gains (ADG) from their bodyweights and growth rates from their wither heights. The compositions of the nutritional values were determined with Weende analysis and the mineral contents were determined by HPLC. We calculated the daily intakes and compared them to the recommendations of literature. We identified the most important nutritional mistakes of the stud farm. In pregnant mares we found exceedingly high energy intake; also, in lactating mares the energy, protein and mineral intake were far below the optimal levels. The diet of growing foals was unbalanced and low in energy, protein, calcium, and phosphorus. After weaning there were 37 animals which we could examine. We found FLD in the distal interphalangeal joint in 26 animals (75%), these lesions mostly occurred in late summer. We recommended a suitable diet plan for the stud farm’s next generation. After weaning of the foals this year, we assessed the prevalence of DOD again: there were 2 out of 20 horses (10%) who presented FLD in the distal interphalangeal joint.