title: Use of linear and non-linear functions to describe the growth of young sport- and race-horses born in Normandy.
abstract: The objectives of this study were to establish standards for growth and to model the evolution of wither height (WH) between birth and adult age in different breeds of sport- and race-horses. Therefore, 398 foals, then yearlings of three different breeds, were measured regularly between birth and 18 months of age. Linear and non-linear functions were compared for describing the growth in each breed group. The monomolecular, Gompertz, logistic and cubic models correctly estimated WH in the three breeds during the first 2 years (R2 = 0.99, s.e. 3.9 to 4.5) and better than the cubic and quadratic models (R2 = 0.93, s.e. = 4.7 to 5.3). The logarithmic and power model seemed better in the last part of the growth period (2 to 6 years, R2 = 0.85, s.e. = 5.6 to 5.9). The linear model did not fit with data on most of the growth period. Comparison of the growth in the three breeds using these models confirmed that race-horses had an intense growth in their first months whereas sport-horses had a more regular growth prolonged in their first years of life.
authors.affiliation: UMR INRA-ENVA 'Biomécanique et Pathologie Locomotrice du Cheval', Ecole Nationale Vétérinaire d'Alfort, 94704 Maisons-Alfort Cedex, France.
authors.forename: J-P
authors.initials: JP
authors.lastname: Valette
authors.forename: C
authors.initials: C
authors.lastname: Robert
authors.forename: J-M
authors.initials: JM
authors.lastname: Denoix