Trkaći konji su jedna od najvrjednijih kategorija u uzgoju sportskih konja, a vrijede onoliko koliko su značajni njihovi plasmani na klasnim utrkama, koji donose novčanu zaradu. Brojnost kasačkih grla, pravilni treninzi, hranidba, održavanje trka, kvalitetnije trkaće staze i stručnost uzgajivača i trenera mogu podići genetsku kakvoću hrvatskog uzgoja kasača. S obzirom da je uzgojni cilj isključivo usmjeren postizanju veće brzine i izdržljivosti u kasu, manje pažnje posvećeno je vanjštini. Cilj ovog rada bio je istražiti morfološka svojstva kasača i njihovu povezanost, odnosno utjecaj tjelesnih mjera na rekordno istrčano vrijeme u utrkama. Istraživanje morfoloških svojstava odnosilo se na izmjerenih 15 tjelesnih mjera 11 kobila i 9 pastuha pasmine hrvatski kasač. Prosječna visina grebena štapom istraživanjem obuhvaćenog uzorka iznosila je 153.63 cm. Utvrđeno je da su pastusi imali statistički visoko značajno (P<0.01) veću visinu grebena i širinu ramena u odnosu na kobile. Pastusi su imali statistički vrlo visoko značajno (P<0.001) duže sapi u odnosu na kobile, a kobile su u odnosu na pastuhe imale statistički značajno (P<0.05) šire sapi. Pastusi su bili vrlo visoko značajno (P<0.001) brži od kobila. Rekordno istrčano vrijeme bilo je u negativnoj korelaciji s visinom grebena (vrpcom i štapom), obujmom grudi, širinom sapi te s visinama leđa, sapi i korijena repa. Sve ostale tjelesne izmjere nisu bile značajno, već samo pozitivno povezane s rekordno istrčanim vremenom u utrci.Racehorses are one of the most valuable categories in sport horse breeding, and their value is worth their rank at class races, which bring financial income. The number of trotters, regular training, nourishment, races and qualitative running tracks as well as the competence of breeders and trainers can raise the genetic quality of the Croatian trotter breeding. The breeding aim is exclusively directed to higher speed achievement and trot endurance, less attention is drawn to the exterior. The aim of this work was to elaborate the morphological characteristics of trotters and the
influence of physical measurements on the record time at trotter races. The morphological characteristics research referred to 15 physical measurements of 11 mares and 9 stallions of the breed Croatian trotter. The average withers height of the research included sample was 153.63 cm. It was established that stallions had statistically significantly higher withers (P<0.01) related to mares. Shoulders width was in stallions statistically significantly higher (P<0.01) related to mares. Stallions had statistically highly significantly longer crupper (P<0.001) related to mares, and mares had statistically significantly (P<0.05) wider crupper. The stallions were highly significantly faster (P<0.001) than mares. The record time at races was in negative correlation with the withers height, the chest girth, back height, crupper and tail root height and with crupper width measured with a tape and a rod. All other physical measures were not significantly, but positively related to record running time