The aim of the paper was to evaluate the effect of genetic polymorphism of kappa-casein on the milk production in Holstein cattle. A total 210 cows of Holstein cattle were use in this study. On the basis of PCR-RFLP analyses we established genotype structure of cattle population and calculated allelic frequencies. In Holstein cattle population was detected all three genotypes – AA (69.52%), AB (27.62%) and BB (2.86%). The frequency of allele A was 83.33% and allele B was 16.67%. Effectiveness of allele incidence and genetic diversity was evaluated with following parameters: theoretical heterozygosity (Heexp), experimental heterozygosity (Heobs), polymorphism information content (PIC), expected homozygosity (E), effective number of alleles (ENA), level of possible variability realization (V%). The Holstein cattle kept in Slovak Republic exhibit high value of homozygosity and low values of polymorphism information content, effective number of alleles and level of possible variability realization. The effect of polymorphism of CSN3 gene on average breeding values for milk production traits as the yield of milk, fat and protein in kilograms as well as contents of fat and protein in percentages was detected using by the packed SAS 9.3 of SAS Enterprise Guide 5.1. We detected statistical significant difference between genotypes only at an average breeding value for the percentage of protein in milk during assessment the variability of observed traits in depending on polymorphism of CSN3 gene. For other breeding values the impact of individual genotypes CSN3 gene on their variability was not observed.

Coconut oil has a high content of lauric acid, which has selective antibacterial activity. This study aimed to explore the effect of coconut oil ingestion on the gastrointestinal microbiomes of pigs. A 14-day-long feeding experiment included 19 pigs in two groups (9 on a normal diet and 10 on a diet supplemented with coconut oil). At the start and end of the experiment, a rectal swab sample was taken from each pig in both groups, and total bacterial DNA was extracted. We used 16S rRNA high-throughput amplicon sequencing to evaluate the microbiome changes during the feeding experiment. A total of 446 operational taxonomic units (OTUs) were detected in the whole sample set. Shannon’s indices of bacterial diversity did not change significantly during the experiment. Changes in the bacterial community during the study period and in response to the coconut oil treatment were highly significant (p < 0.001). During the study, an increase in the abundance of Lactobacillus was detected in the group treated with coconut oil. An increase in Alloprevotella, Bifidobacteriales, and Lactobacillales and a decrease in Corynebacterium, Mitsuokella, Psychrobacter, and Pseudomonadales were attributed to the coconut oil treatment. Although the addition of coconut oil to pig feed did not affect Shannon’s index of diversity, it had a positive effect on the abundance of bacterial groups that are considered to be commensal and/or probiotic.

The aim of this study was to analyze the polymorphisms of the beta-casein gene and describe the association between the beta-casein genotypes and milk production in high milk-production Slovak Holstein cattle herds. Genomic DNA was isolated from the hair root samples of 1478 cows using a commercial column kit. The detection of the specific alleles A1 and A2 of the CSN2 gene was carried out using three molecular-genetics methods, including the TaqMan allelic discrimination assay, ACRS-PCR and SBE primer extension technology. The results of the molecular-genetic analysis were used for calculating the genetic structure in the analyzed population. All three genotypes, including A1A1 (5.28%), A1A2 (37.08%) and A2A2 (57.64%), were detected. The frequency of the allele A1 was 23.82% and the allele A2 was 76.18%. The statistical analysis and data preparation were performed using the SAS 9.2 Enterprise Guide 4.2 software. A general linear model (GLM) and the least squares means adjusted for multiple comparisons were used. A significant positive effect of the beta-casein genotype A2A2 on protein in kilograms and partially for the protein content in Holstein cows was found. Only the highest the least squares means for the fat percentage was found for the genotype A1A1 compared to the genotype A2A2. This can be considered a slightly negative trend.

Bacterial contamination of semen is an important factor connected to the health status of bulls that may significantly affect semen quality for artificial insemination. Moreover, some important bovine diseases may be transmitted through semen. Up to now, only a very limited number of complex studies describing the semen microbiome of bulls have been published, as many bacteria are hard to cultivate using traditional techniques. The 16S rRNA high-throughput sequencing strategy allows for the reliable identification of bacterial profiles of bovine semen together with the detection of noncultivable bacterial species. Fresh samples from Holstein Friesian breeding bulls (n = 55) were examined for the natural variability in the present bacteria. Semen doses were selected randomly from Slovak Biological Services in Nitra, Slovak Republic. The most predominant phyla within the whole dataset were Firmicutes (31%), Proteobacteria (22%), Fusobacteria (18%), Actinobacteria (13%) and Bacteroidetes (12%). Samples of semen were divided into two separate clusters according to their microbiome compositions using a cording partition around a medoids analysis. Microbiomes of the first cluster (CL1) of samples (n = 20) were based on Actinobacteria (CL1 average = 25%; CL = 28%) and Firmicutes (CL1 = 38%; CL2 = 27%), while the second cluster (CL2; n = 35) contained samples characterized by a high prevalence of Fusobacteria (CL1 = 4%; CL2 = 26%). Some important indicator microbial groups were differentially distributed between the clusters.

The goal of work was identification A1 variant of bovine beta casein which involves ischemic heart disease and diabetes mellitus in human. The digestion of A1beta casein can result in the production of bioactive beta casomorphin-7 (BCM-7); this is not the case with A2. This bioactive peptide has been linked to physiological traits that may elicit effects on components of the vascular and immune systems. The material involved 111 Slovak Spotted breed. Bovine genomic DNA was extracted from whole blood by using commercial kit, and used in order to estimate beta-casein genotypes by means of PCR-RFLP method. The PCR products were digested with DdeI restriction enzyme. In the population included in the study were detected all three genotypes, homozygote genotype A1A1 (14 animals), heterozygote genotype A1A2 (37 animals) and homozygote genotype A2A2 (60 animals). In the total population of cattle homozygotes A2A2-0.5405 were the most frequent, while homozygotes A1A1-0.1261 were the least frequent ones. This suggests a superiority of allele A2 (0.7072) which does not produce BCM-7, and thus is safe for human consumption. The expected homozygosity for gene CSN2 is in the population stated a slight increase in homozygosity (0.5858). This caused a slight decrease in the level of possible variability realization (41.80%), which corresponds to the effective number of alleles (1.7071).