This study showed useful genetic diversity and phylogenetic relationship data that can be utilized for the development of a new breeding strategy by AHLBB. The results presented could also contribute to the proper selection of animals for further whole genome scan studies of Limousins.

Variance, covariance components, heritability, breeding values (BV) and genetic trends in calving interval (CI) of the Limousin population in Hungary were evaluated. A total of 3,008 CI data of 779 cows from three herds in 1996–2016 were processed. For influencing effects GLM method, for population genetic parameters and BV estimation BLUP animal model, for trend analyses linear regression was applied. The average CI obtained was 378.8 ± 3.1 days. The variance distribution components of the phenotype were as follow: age of cow at calving 34.30%, season of calving 26.09%, year of calving 23.00%, sire 7.45%, herd 3.23%, sex of calf 0.33% and type of calving 0.30%. The heritability of CI proved to be low (h2 d = 0.04 ± 0.02 and 0.03 ± 0.02; h2 m = 0.01 ± 0.02). The repeatability was low (R = 0.03 ± 0.02). Based on the phenotypic trend calculation, the CI of cows decreased by an average of 0.60 days per year (R 2 = 0.19; P < 0.05). In case of genetic trend calculation, the average BV of sires in CI increased 0.07 and 0.17 days per year (R 2 = 0.23 and 0.27; P < 0.05).

Some environmental effects, population genetic parameters, breeding value of Limousin breeding bulls, also phenotypic and genetic trends in the age at first calving (AFC) of cows between 1992 and 2013 were estimated. Data were served by the Limousin and Blonde d'Aquitaine Breeders Association, in Hungary. The study was extended to three herds and 1157 cows. GLM method was used for the study of different effects, the BLUP animal model for estimation of population genetic parameters and breeding values (BV), and one-way linear regression analysis for trend calculations.The overall mean value of the AFC was estimated to be 34.7±0.4 months. The contribution of the evaluated factors to the phenotype was as follows: herd 73.51%, birth year of cow 13.02%, sire 6.74%, birth season of cow 1.62%. The heritability of AFC proved to be low (h 2 = 0.08±0.07 and h 2 = 0.01±0.04). There were relatively small differences in the estimated BV of the studied sires for the AFC. Based on the phenotypic trend calculation, the AFC of cows decreased by an average of 0.33 months per year, however no significant change was found in the genetic trend during the study period.

Population genetic parameters, direct and maternal breeding value, the genetic trend in the weaning weight of Limousin beef cattle calves were estimated in the period 1992–2019. Data of 19 764 calves (15 437 purebred Limousin and 4 327 crossbred) were computed. Crossbred calves were sired by Limousin breeding bulls from Simmental dams. Calves in question came from 37 herds and from 240 sires in Hungary. DFREML and MTDFREML software was used for the estimation of population genetic parameters, BLUP animal model for breeding value estimation. Weighted linear regression model was used for describing genetic trends. The maternal heritability (h²_m ± SE = 0.29 ± 0.03; 0.32 ± 0.10) was approximately half of the direct heritability (h²_d ± SE = 0.63 ± 0.05; 0.68 ± 0.12). The direct maternal covariance is negative, the direct maternal genetic correlation coefficients (r_dm ± SE = –0.80 ± 0.03 and –0.96 ± 0.07) are strong negative. The Spearman rank correlation between direct and maternal breeding value in purebred population is moderate and negative (r_rank = –0.33; P &lt; 0.01), in crossbred population it is strong and negative (r_rank = –0.99; P &lt; 0.01). According to direct and maternal breeding values of sires, the genetic trend of the weaning weight of purebred and crossbred Limousin calves appeared stagnant during the examined period (b = +0.01 kg/year to +0.19 kg/year). Keywords: d

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