The genetic parameters for the survival of Holstein cows, analysed in nine consecutive time periods during the first three calving intervals, were estimated. The earlier the animals are culled, the more they are informationally underestimated. This undervaluing can be remedied by using a weighted analysis that balances the amount of information. If the method of estimating breeding values changes, the genetic parameters will also change. The Holstein cattle dataset from 2005 to 2017 used in this study included 1,813,636 survival records from 298,290 cows. The pedigree with three generations of ancestors included 660,476 individuals. Linear repeatability models estimated genetic parameters for overall and functional survivability. Due to weights, heritability increased from 0.013 to 0.057. Repeatability with weights was 0.505. The standard deviations of breeding values were 1.75 and 2.18 without weights and 6.04 and 6.20 with weights. Including weights in the calculation increased the additive variance proportion and the breeding values' reliabilities. We conclude that the main contribution of the weighted method we have presented is to compensate for the lack of records in culled individuals with a positive impact on the reliability of the breeding value.

The aim of this study was to estimate the effects of crossbreeding on milk production and milk components in crossbred Tsigai, Lacaune, and Improved Wallachian sheep used to create a synthetic Slovak dairy sheep population. The local breeds Tsigai and Improved Wallachian were crossed with the high-yielding breed Lacaune to increase milk yield. The effects of crossbreeding were evaluated based on breed and heterosis effects. The database used consisted of 23 018 lactations from 15 888 ewes. The effects of crossbreeding on milk production and fat and protein content were estimated using the restricted maximum likelihood method in REMLF90. Fixed effects on milk yield were also studied. In ewes with a 100% heterosis effect (ewes from purebred parents of different breeds), the heterosis effect increased milk production by 11.642 kg, milk fat production by 0.772 kg, and protein production by 0.565 kg per milking period. The effect of the Tsigai breed on milk production was -21.98 kg compared to Lacaune, while for the Improved Wallachian breed, the value was -38.58 kg. The Tsigai direct breed effect reduced fat production by 1.56 kg and protein production by 1.34 kg. The Improved Wallachian direct breed effect was -2.71 kg for fat production and -2.27 kg for protein production.

The aim of this study was to present the trend of inbreeding and to estimate the effect of inbreeding on the growth ability of lambs in the three most common sire breeds in the Czech Republic: Suffolk (SF; n = 49 345), Charollais (CH; n = 14 189) and Texel (T; n = 10 481). The growth ability of lambs was evaluated between 2000 and 2019 based on the weight at 100 days of age. The average inbreeding coefficient for Suffolk, Charollais and Texel was 0.013, 0.012 and 0.011, respectively. The average number of known generations was 5.260 for Suffolk, 3.355 for Charollais and 3.709 for Texel. To evaluate growth ability, lambs were divided into four groups according to the inbreeding coefficient (F = 0.00, 0.00 < F ≤ 0.062 5, 0.062 5 < F ≤ 0.125, F > 0.125). The results of this study show the negative effect of inbreeding on the growth ability of lambs was significant (P < 0.05). The regression coefficients of the weight for Suffolk, Charollais and Texel lambs for a change of 1% in inbreeding were estimated to be -0.028, -0.053 and -0.048, respectively.

In recent years number and quality of ancient DNA samples have been constantly rising. Thanks to advances in ancient DNA isolation and sequencing techniques we are able to access variability of many ancient populations. Today autosomal SNPs and uniparental markers in Y chromosome or mitochondrial DNA provide valuable insight into ancient population genetics. So far genotypes of few thousands of prehistoric samples have been published. The results are spread across many publications in different formats. We have created a hand-curated database of ancient human mitochondrial genomes where the mtDNA sequences and associated sample descriptors can be found at https://amtdb.org. Recent Advances in Genetic Evaluation of Italian Holstein: Results from Latteco Project

The early post-parasitic phase is considered to be the most vulnerable life stage of the endangered freshwater pearl mussel (Margaritifera margaritifera), yet little is known about the spatial variability in juvenile performance at a river scale. The main aim of this study was to determine within-river variation in habitat suitability for juvenile M. margaritifera. The growth and survival rates of juveniles (one and two year old) were measured in the Vltava River (Czech Republic) in relation to several physical and chemical variables using a total of 166 bioindication units (individual mesh cages and sandy boxes) during two thermally different vegetation seasons. Three spatial scales were studied: a longitudinal river profile, bottom habitat types, and hyporheic microhabitats. Both the survival rate and growth of the exposed juveniles varied considerably within the studied river. The effect of the longitudinal river profile and the roles of temperature, oxygenation within microhabitats, episodic pollution, and exposure method were demonstrated. This study represents the first example of a hierarchized approach to the assessment of a riverine mussel biotope with the use of bioindication methods. The results demonstrate the importance of the scale and bioindication method used in understanding the suitability of a river environment to juvenile freshwater mussels.