Mitochondrial DNA and nonrecombinant parts of Y-chromosome DNA are a great tool for looking at a species’ past. They are inherited for generations almost unaffected because they do not participate in recombination; thus, the time of occurrence of each mutation can be estimated based on the average mutation rate. Thanks to this, male and female haplogroups guide confirming events in the distant past (potential centers of domestication, settlement of areas, trade connections) as well as in modern breeding (crossbreeding, confirmation of paternity). This research focuses mainly on the development of domestic sheep and its post-domestication expansion, which has occurred through human trade from one continent to another. So far, five mitochondrial and five Y-chromosome haplogroups and dozens of their haplotypes have been detected in domestic sheep through studies worldwide. Mitochondrial DNA variability is more or less correlated with distance from the domestication center, but variability on the recombinant region of the Y chromosome is not. According to available data, central China shows the highest variability of male haplogroups and haplotypes.

The objective of this study was to estimate lamb birth weight based on body dimensions. We monitored 101 lambs (61 Charollais lambs, 27 Kent lambs, and 13 their crossbreds) at a selected commercial flock. Birth weight, chest circumference (CC), head circumference (HC), and shin circumference (SC) were measured immediately after birth using a tape measure. Correlation analysis indicated the promising use of CC (r = 0.795; p < .001) or HC (r = 0.679; p < .001) for estimating body weight. Statistical models with one body measurement indicated that a model with CC as a covariate had the highest coefficient of determination and the lowest Akaike’s information criterion, corrected Akaike’s information criterion, and Bayesian information criterion. The defined criteria generally identified that models with SC, HC, and CC and models with HC and CC as covariates were the best. Residual analyses verified our results, but more extensive analyses of other breeds under different breeding conditions should be conducted to confirm and generalise our results.

This study investigated the effect of glycerol added in different phases of sperm equilibration on CASA and flow cytometry parameters of thawed ram spermatozoa. Sperm was collected from adult Wallachian rams. The freezing extender was glycerol-free ANDROMED^® (Minitub GmbH, Tiefenbach, Germany) supplied by 6% exogenous glycerol at different stages of the cryopreservation process. The purpose of this study was to compare two strategies of glycerol addition for sperm cryopreservation. The first strategy included the use of a glycerol-free extender for the procedure of glycerol-free equilibration and chilling, with the glycerolation of the extender by 6% glycerol shortly before sperm slow freezing (GFA). The second strategy included the use of a freezing extender already glycerolated by 6% glycerol before the equilibration and chilling of sperm and following slow freezing (GA). Sperm samples were analyzed after equilibration (but before freezing) and after thawing (at T0, T1 h, and T2 h time points). iSperm^® mCASA (Aidmics Biotechnology Co., LTD., Taipei, Taiwan) was used for the evaluation of sperm kinematics. Flow cytometry was used to measure sperm viability (plasma membrane/acrosome intactness) and mitochondrial membrane potential. The obtained results significantly demonstrated that the glycerol-free equilibration with the addition of glycerol shortly before freezing is a perspective strategy for cryopreservation of Wallachian ram sperm.

This study aimed to evaluate the influence of the internal factors of ram age and litter-of-origin on semen quality during the cryopreservation process in Sumava sheep rams. This breed is included in the protected genetic resources of the Czec...

Acta Universitatis Agriculturae et Silviculturae Mendelianae Brunensis, the scientific journal of the Mendel University in Brno, Czech Republic