Growth problems, from left to right:
Knock knees, epiphysitis, contracted tendons, epiphysitis
Developmental Orthopaedic Disease (DOD) is generally recognised as a failure of the cartilage to develop into mature healthy bone and can manifest as epiphysitis, osteochondrosis, bone cysts, juvenile arthritis or wobbler syndrome.
There are several factors involved in growth related skeletal problems:
Genetic predisposition including poor leg conformation and the inability to absorb certain nutrients.
Management including limited activity, too much forced activity and trauma from carrying too much weight.
Nutrition, starting from the pregnant mare absorbing inadequate nutrients for foetal development and including large grain based meals fed to youngstock, and infrequent feeding.
Many researchers have shown that high protein diets are not directly linked to DOD however, a high energy diet accompanied by an inadequate supply of minerals can result in developmental problems. Typically, this would occur when straight cereals are fed without a supplement or balancer designed specifically for breeding and youngstock or where grass or forage is rich in calories and, again, no balancing nutrients are supplied. It is now also widely accepted that controlled exercise alongside balanced nutrition is important for the development, strength and remodelling ability of bone in the young horse.
As a general rule, problems evident in all four limbs are likely to be related to nutrition or genetics, whilst those appearing in a pair of limbs (fore or hind) could be caused by management or conformation, giving rise to uneven weight distribution and trauma. If only one leg is affected, it is likely to be related to conformation or it could be due to an old injury which has caused trauma to one particular area of the limb. Whilst attention to nutrition may not directly affect those problems which are trauma or conformation-related, providing all the nutrients to support correct growth can only serve to help the body repair and develop associated tissues.