The studbook of the Andalusian horse comprising a total of 75,389 individuals (6318 of them classified as Carthusians) was analysed in order to ascertain the genetic history of the breed and, specially, to evaluate its genetic variability and the influence of the Carthusian strain in the breed. Although there is no possible way to identify studs acting as Nucleus in the breed, there is a high concentration of genes and individuals' origin. The effective number of studs producing grandfathers was of 10.6. The equivalent number of founders was 1948.5 individuals (370.5 Carthusians). The effective number of founders was 39.6 and the effective number of ancestors 27. Only 6 ancestors were necessary to explain 50% of the genetic variability of the breed. The average values of inbreeding and average relatedness for the whole Andalusian horse population were, respectively, 8.48% and 12.25%. The same values for the Carthusian strain were higher (9.08% and 13.01%) even thought the generation interval for the strain was larger than that for the whole population (12.43 versus 10.11 years). In any case, inbreeding in Andalusian horse breed seems to have a remote origin and linked to the Carthusian individuals. The total contribution of the Carthusian founders to the populations accounted for up to 87.64% of the population. In turn the Carthusian ancestors explained 80.46% of the genetic variability of the breed. No differentiation was found between Carthusian and non-Carthusian reproductive individuals using genealogical F ST (0.000026). It can be concluded that the distinction between Carthusian and non-Carthusian individuals within the Andalusian horse breed does not have genetic support. The unbalanced use of the Carthusian individuals with lower average relatedness values for reproduction is proposed to preserve the genetic variability of the breed.

The aims of this study were, first, to evaluate eye temperature (ET) with infrared thermography and heart rate (HR) to measure stress in horses during show jumping competitions and their relationship with competition results, and second, to evaluate the influence of different extrinsic and intrinsic factors of the horse on the stress measurements analysed. One hundred and seventy-three Spanish Sport Horses were analysed for ET and HR, and these measurements were taken 3 h before the competition, just after and 3 h after it. Two interval measurements were also assessed for each parameter. Positive significant correlations were found between ET and HR, measured before (r=0.23), just after competition (r=0.28) and for the later interval (r=0.26), whereas negative correlations with competition results were found only for ET when measured just after competing (r=−0.25). Two intrinsic factors (genetic line and age) and no extrinsic factors showed significant differences for ET, whereas one intrinsic factor (age) and two extrinsic factors (journey duration and number of training hours) showed significant differences for HR. The marginal means showed significantly higher ET values for the Anglo-Arab genetic line and for 5-year-old animals. HR values were significantly higher for 4-year-old animals, for horses which had travelled 4 to 6 h and for horses that had 3 to 6 h of daily training. This study suggests that, although ET and HR seemed to share a similar physiological basis, the factors that most influenced each parameter were different. Finally, ET seems to be a suitable tool for assessing stress during show jumping competitions in horses.

Summary: The objective of this study was to test the performance of a recently proposed methodology for the estimation of realized effective size (N_e) based on individual increase in inbreeding (ΔF_i) on several real pedigrees: (a) an experimental mice population; (b) a closed pedigree of fighting bulls; (c) the Spanish Purebred (SPB, Andalusian) horse pedigree; (d) the Carthusian strain of SPB pedigree; (e) the Spanish Arab horse pedigree; and (f) the Spanish Anglo‐Arab horse pedigree. Several reference subpopulations were defined on the basis of generation length in order to consider only animals in the last generation, to assess the influence of the pedigree content on the estimates of N_e. The estimates of realized N_e computed from ΔF_i () tended to be higher than those obtained from regression on equivalent generations. The new parameter remained approximately stable when pedigree depth achieved about five equivalent generations. Estimates of take into account the genetic history of the populations, the size of their founder population, and the mating policy or bottlenecks caused by poor use of reproducing individuals. The usefulness of the realized N_e computed from individual increase in inbreeding in real pedigrees is also discussed.