Analysis of the mare breeding population of Haflinger breed in the Czech Republic

The aim of this study was to analyse the conformation traits and body dimensions of Haflinger mares registered in the Czech Republic studbook. The study focused on the effects of age at studbook entry, year of birth, proportion of Arabian genes, and country of origin on various parameters. Data were collected from 825 mares, including scores obtained during the studbook entry evaluation and body measurements such as withers height measured with a stick (WHS), withers height measured with a tape (WHT), chest girth (CG), and cannon bone circumference (CBC). Based on these data, the bone index (BI) and body massiveness index (MI) were calculated. Statistical analysis was performed using multifactor analysis of variance (ANOVA) and Scheffe's post-hoc testing method. The results showed that the age at studbook entry significantly affected conformation scores, chest girth, cannon bone circumference, and both indices (MI, BI). Mares aged 3-4 years had significantly higher conformation scores compared to mares aged 5-6 years (P = 0.001) and mares aged 7 years and older (P = 0.000). Mares aged 5-6 years and those aged 7 years and older showed higher CG values (P = 0.002, P = 0.000) and CBC values (P = 0.010, P = 0.001). Furthermore, the year of birth had a highly significant impact on all variables studied. The withers height of mares born between 2011 and 2020 was, on average, 3.49 cm higher (144.84 cm) than that of mares born between 1987 and 2000 (141.35 cm) (P < 0.000). Regarding CG, a statistically significant increase was observed in mares born in 1987-2000 and 2001-2010, with chest girth increasing from 180.45 cm to 183.76 cm (P = 0.016). However, a subsequent decrease to 179.91 cm was noted in mares born between 2011 and 2020 (P = 0.002). The influence of the proportion of Arabian genes was significant for WHS, where mares with a higher proportion of Arabian genes (>1.56%) showed lower WHS (141.74 cm) compared to mares with a lower proportion (143.86 cm) or no Arabian genes (143.01 cm). While ANOVA demonstrated a significant effect of Arabian genes on CBC, Scheffe's post-hoc test did not confirm this finding. No statistically significant differences were observed in other body dimensions based on the proportion of Arabian genes. The influence of the country of origin was statistically significant for all variables except WHS and WHT. Regarding the conformation scores, mares from the Czech Republic scored lower (6.98) than Austrian mares (7.22, P = 0.000). Additionally, CG was significantly lower in Austrian mares (178.58 cm) compared to Czech mares (182.54 cm, P = 0.000). Austrian mares also had significantly lower MI (P = 0.000) and BI (P = 0.040), with Austrian indices at 124.71/13.31 and Czech indices at 127.77/13.41. Based on this empirical evaluation of the current and original population of Haflingers in the Czech Republic, the connections and influence of individual factors during breeding are revealed. The results of our analysis have built an objective scientific basis and they allow the breeding organisation to determine the further breeding process.