This article follows on from last month?s discussion relating to feeding for improved fertility in mares and will discuss feeding foal and weanlings. The motto for feeding young horses is ?optimal not maximal?.  Overfeed a young horse with a high or unbalanced NSC diet could cause developmental disorders.

Feeding the Foal:
At seven to ten days of age, the foal will begin to sample solid food, although milk provides most of its nutrients until two months of age.  Following peak lactation at two months, the quality and quantity of mares milk declines until the foal?s needs cannot be met with milk alone.  The foal must then be supplemented with other feeds such as green pasture and creep feeds.

Creep Feeding:
Creep Feeds are supplementary feeds fed to the foal - starting at one to three months of age - to help meet the shortfall between what the milk can supply and what the growing foal requires.  Although mares and foals can be fed the same concentrate, foals have different nutrient requirements so should ideally be fed their own creep feed, separate to the mare.   Creep feeds should be palatable, nutrient-dense concentrates that provide adequate energy, amino acids and balanced levels of minerals. Creep feeding can also help reduce stress at weaning time, because the foal is already accustomed to concentrate feeds.

Developmental Orthopaedic Disease (DOD):
To have a healthy horse and avoid Developmental Orthopaedic Disease (DOD), the weanling must be provided with a balanced, palatable ration that supports steady growth. 

DOD refers to developmental disorders in horses including epiphysitis, OCD and contracted tendons.  Weanlings are at risk of DOD if they receive excess energy (high NSC diets), inadequate essential amino acids and insufficient or unbalanced levels of calcium, phosphorus and certain trace minerals.  The glucose and insulin response to feeding high NSC diets has also been associated with DOD, so ideally creep and weanling feeds should not be high in rapidly fermentable carbohydrates.

Rapid growth spurts associated with compensatory growth may also predispose the foal to DOD, and should be avoided by ensuring the foal is growing at a constant rate and not starved at any stage.  Stress at weaning time can reduce the foal?s appetite and cause weight loss or a growth slump.  Compensatory growth occurs when the foal regains its appetite and quickly gains weight. Providing a weanling feed similar to the creep feed and executing low-stress weaning should help the weanling maintain appetite and steady body condition during the weaning process.  If weight loss does occur due to illness or reduced appetite, growth should be compensated for very gradually over several months.

Feeding the Weanling:
Foals can digest and utilise fibre by three to four months of age (ie. by time of weaning).  Green, mixed pasture that is actively growing and not overstocked should supply the bulk of energy and protein for the weanling.  In this situation, a small mixed feed of lucerne chaff, calcium, phosphorus and correct trace minerals may be all that the weanling requires. 

If pasture quality or availability is inadequate, the weanling will require medium quality lucerne or clover hay and a concentrate feed.  The concentrate should be palatable and contain 14-16% protein, energy, calcium, phosphorus, copper, zinc, manganese, iodine, selenium and vitamin E in correct, balanced amounts. The feed should not contain more than 15% NNSC. A number of excellent creep and weanling feeds are commercially available. 

Monitoring youngsters:
Growing horses should be assessed regularly for body condition, weight and signs of developmental problems.  If youngsters are growing too quickly or putting on excess condition, the ration must be adjusted accordingly to prevent potential developmental problems. In young horse nutrition, slow and steady wins the race.  Optimal, but not maximal growth should be the aim of feeding foals and weanlings.

Recent research
Recent studies at the University of Queensland have shown that feeding pregnant mares a high NSC diet can cause gestational diabetes in foals. It is suggested that if the mare is suffering insulin resistance, she will parasitise the liver of the foal causing IR in the foal, causing leg deformities and tendon damage.  Gestational diabetes is recognised in women, and it is possible that it will occur in mares and foals.