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ABSTRACT:The paper deals with the greying process, melanoma, and vitiligo depigmentation occurrence in Old Kladruber horses (OKH). The study includes 376 animals of both sexes at the age of 1-25 years. The evaluation was performed repeatedly during 4 consecutive years. The greying status was measured spectrophotometrically on four body parts using L*a*b* colour system. Melanoma and vitiligo were detected visually and by palpation in all the animals and classified using 5 (3) grade scale. The GLM procedure of SAS package was used to examine the influence of the effects of line, age, sex, stud, and year of evaluation. The GLM analysis confirmed a significant impact of age on greying. Parameter L* showed progressive increase until 10 years of age when all horses reached final grey level. Subsequent analyses suggested the influence of sex, i.e. a notably higher level of greying in mares. The incidence of melanoma was confirmed. Melanoma in OKH most frequently occurs on the bottom of the tail or at the anal and perineal area. Probably only benign forms of melanoma have been detected. The global occurrence of melanoma in OKH (ca. 13%) is substantially lower than in Lipizzan and Camargue horses. Overall incidence of melanoma in horses at the age of 15 and older reached 68%. Genetic parameters were estimated for melanoma grade, grey level, and vitiligo. Greying is strictly influenced by age (h 2 = 0.52 ± 0.07). Prevalence of melanoma progresses with age (h 2 = 0.07 ± 0.04). Vitiligos of both facial and anal parts are influenced by the effects studied (h 2 = 0.20 ± 0.05 and 0.34 ± 0.06 for vitiligo A and vitiligo F, respectively).

Three draught horse breeds are maintained in the Czech Republic: the Silesian Noriker (SN), the Noriker (N), and the Czech-Moravian Belgian (CMB). Because the SN and CMB populations are currently closed to outside breeding and are endangered (Genetic Resources), the loss of the genetic variation these horses represent is concerning. Genetic diversity within and between these three breeds and their population structures was analyzed based on pedigree information. Our goal was to identify and quantify factors that affected their genetic variability. The effective population size was analyzed in each breed. The numbers of generations were 22, 32, and 32 for the SN, N, and CMB breeds, respectively, with average equivalent known generations of 9.81, 8.45, and 8.91, respectively. The effective numbers of founders and ancestors contributing to the current genetic pool were, respectively, 69.42 and 22.32 for the SN breed, 98.48 and 42.20 for the N breed, and 43.33 and 23.32 for the CMB breed. The average inbreeding coefficients were 4.6%, 2%, and 4% for the SN, N, and CMB breeds, respectively, and the average inbreeding rate was 0.5% for the SN and CMB breeds and 0.2% for the N breed. The corresponding estimates of effective population size were 95, 195, and 101 for the SN, N, and CMB breeds, respectively. These statistics suggest that the genetic variability has decreased, and without changes in breeding strategy the genetic variability might continue to decline. Using genealogical F-statistics, small genetic differences were identified between the analyzed populations (F ST = 0.02).

Czech local poultry breeds face high risks of extinction. Because these populations are closed, they are more likely to lose genetic diversity. The aim of this analysis was to determine the loss of genetic diversity in three Czech autochthonous poultry breeds. Pedigree data from a total of 1 932 Czech Gold Speckled Hens, 325 Czech White Geese and 111 Czech Crested Geese registered in studbooks between 2000 and 2018 were evaluated. Data were analysed to determine the major factors that affect the genetic variability of these breeds. The average numbers of equivalent complete generations ranged from 2.53 to 4.82. The effective numbers of founders were from 29 to 59, representing from 43% to 62% of the total number of founders. The effective number of ancestors was estimated in the range of 21 to 41. The average inbreeding coefficient and relatedness coefficient (in parentheses) for the reference populations were 2.0% (6.5%), 1.9% (4.9%) and 2.1% (9.3%), respectively. The results showed that the effective population size derived from the rate of inbreeding ranged from 46 to 108 and if derived from the rate of coancestry it ranged from 35 to 74. With regard to these results, the analysed breeds showed a high probability of allele loss and consequent loss of genetic diversity.

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Estimated breeding values (EBVs) and genomic enhanced breeding values (GEBVs) for milk production of young genotyped Holstein bulls were predicted using a conventional BLUP -Animal Model, a method fitting regression coefficients for loci (RRBLUP), a method utilizing the realized genomic relationship matrix (GBLUP), by a single-step procedure (ssGBLUP) and by a one-step blending procedure. Information sources for prediction were the nation-wide database of domestic Czech production records in the first lactation combined with deregressed proofs (DRP) from Interbull files (August 2013) and domestic test-day (TD) records for the first three lactations. Data from 2627 genotyped bulls were used, of which 2189 were already proven under domestic conditions. Analyses were run that used Interbull values for genotyped bulls only or that used Interbull values for all available sires. Resultant predictions were compared with GEBV of 96 young foreign bulls evaluated abroad and whose proofs were from Interbull method GMACE (August 2013) on the Czech scale. Correlations of predictions with GMACE values of foreign bulls ranged from 0.33 to 0.75. Combining domestic data with Interbull EBVs improved prediction of both EBV and GEBV. Predictions by Animal Model (traditional EBV) using only domestic first lactation records and GMACE values were correlated by only 0.33. Combining the nation-wide domestic database with all available DRP for genotyped and un-genotyped sires from Interbull resulted in an EBV correlation of 0.60, compared with 0.47 when only Interbull data were used. In all cases, GEBVs had higher correlations than traditional EBVs, and the highest correlations were for predictions from the ssGBLUP procedure using combined data (0.75), or with all available DRP from Interbull records only (one-step blending approach, 0.69). The ssGBLUP predictions using the first three domestic lactation records in the TD model were correlated with GMACE predictions by 0.69, 0.64 and 0.61 for milk yield, protein yield and fat yield, respectively.