Foal growth and minerals — even beats fast

In the first months of life and in the first year the horse lays down the greater part of its skeletal development. This makes this phase nutritionally sensitive like no other — and it makes a widespread reflex problematic: to raise as swiftly as possible a large, sturdy youngster. For a resilient foundation what counts is not the pace, but the evenness of the growth.

Why abrupt growth is a risk

Bone and cartilage mature in an ordered sequence. An energy excess in the ration — for example through plentiful concentrate feed — can trigger growth spurts that overtake this maturation. In the specialist literature an excess of energy and abrupt growth jumps are discussed as factors in the context of the developmental disorders of the skeleton (Developmental Orthopaedic Disease, DOD, to which osteochondrosis also belongs). This is an editorially classifiable connection from the research, not a mechanism that a feed could control or a disorder could cure.

Copper is cofactor of lysyl oxidase, an enzyme that catalyses the cross-linking of collagen and elastin in the connective tissue — thus directly involved in the stability of cartilage and bone matrix. In a controlled work by Knight and colleagues (Equine Veterinary Journal 1990) foals of copper-poor fed groups showed clearly more cartilage and joint findings than copper-supplemented animals. Zinc acts in a flanking role in keratinisation and as cofactor of numerous enzymes. Both trace elements deserve particular attention in rearing.

The calcium-phosphorus ratio

In the growing horse it depends not only on the absolute quantities of calcium and phosphorus, but on their ratio to one another. A range of about 1.5 to 2 parts of calcium to 1 part of phosphorus serves as orientation; a phosphorus excess — for example through much grain with scarce forage — can disturb the calcium utilisation. Precisely in the growth phase this balance is no detail, but the basis of the bone mineralisation.

The supply of the foal moreover begins before birth: the copper status of the pregnant mare shapes the liver stores of the newborn, which itself receives only limited copper via the milk. A requirement-appropriate supply of the broodmare in the last third of pregnancy is thereby part of the foal supply — not only the supplementary feeding of the weaned young horse.

The most robust strategy is therefore unspectacular: plenty of structure-rich forage, a mineral feed attuned to rearing with sufficient copper and zinc, a calcium-phosphorus ratio kept in view — and the willingness to throttle energy rather than to push it. Evenly grown young horses are the goal, not the largest.