Anuario Raza Polo Argentino Anuario2018 | Page 253

Equine Growth and Development
Equines are naturally precocious animals and their
development is exceptionally early. Already during
the first stages of their lives they move freely and
speedily.
We perceive, therefore, that during the period of time
between birth and maturity, growth coefficients of
the three main tissues in order of magnitude are
bone, muscle and fat. This in biology we define as
“allometric growth” of the tissues. As seen in the
diagram, during gestation and at an early age, the
bone grows more rapidly when compared to the
total increase of body mass.
Growth and development in horses is expressed by
an increase in weight and dimensions over time. At
birth, a foal’s standing height is approximately 60%
of what its final height will be, whereas its weight
is only 9-12% of the weight of the adult horse.
Thus, the first evidence of this is that the skeleton
is already more developed than its muscle and
adipose tissues (gestation stage). During the first
month it may double its weight, and at 6 moths,
multiply it by five. When it reaches the age of one
year, the foal could have developed up to 88-90%
of its total standing height, and approximately 65%
of its adult weight.
It becomes clear, therefore, that during the whole
of the first year of its life, development of the
musculoskeletal system is a priority. After the age
of 18 months, bone lengthening decreases and its
density and consolidation prevail. As additional
data we may add that if the rate of mineralization of
the bone (measured in shanks or third metacarpal
bone) is compared with age, the pattern it follows is
more similar to that of weight rather than standing
height. At 6 months the equine reaches 68.5% of
its adult bone mineral content, and when it reaches
one year of age, 76% of its maximum content.
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