The objectives of this study were (1) to examine different shapes of lactation curves for milk, fat, protein and lactose yields and urea content in milk fitted by the Wilmink function using the test-day (TD) records and (2) to find the function that best describes test-day records beyond 305 days in milk (DIM) for Polish Holstein–Friesian cows. The data were 6,955,768 TD records from the 702,830 first six lactations of 284,193 Polish Holstein–Friesian cows. Cows calved in 19,102 herds between 2001 and 2018. The following functions were fitted to TD data from each lactation: (1) Wilmink model fitted to the whole lactation, (2) Wilmink model fitted to TD records from 5 to 305 DIM and linear function fitted to TD records from 306 to 400 DIM, (3) Wilmink model fitted to TD records from 5 to 305 DIM and squared function fitted to TD records from 306 to 400 DIM. The present study showed that urea content in milk was modelled slightly worse than other milk traits. The results suggested that the course of lactation could be successfully modelled by a nonlinear model, for example, the Wilmink function, for up to 305 DIM, and by the linear or squared function afterwards.

Silver nanoparticles possess valuable physical, chemical, and biological properties, rendering them widely applied as bioactive agents in the industry. Nonetheless, their influence on the natural environment and on living organisms remains unclear. Therefore, this study aims to investigate the impact of polymer composites containing silver nanoparticles on sperm cells. The nanosilver polymer composites were chemically synthesized, employing sodium alginate as the stabilizer. The reducing agents employed were solutions comprising sodium borohydride and xylose. The concentration of silver nanoparticles obtained after synthesis was 100 parts per million. The examined biological species were rabbit sperm cells. The impact of nanosilver on the sperm was assessed through the elucidation of the toxicity profile, comet test, and analysis of morphological characteristics of the animal cells. The results of the study demonstrate a twofold impact of polymer composites infused with silver nanoparticles on domestic rabbit sperm when obtained through chemical synthesis using two reducing agents (xylose and sodium borohydride) at a 10 ppm concentration. The comet test showed no harmful effect on the DNA integrity of rabbit sperm by the tested compounds. Twenty-four-hour exposure of rabbit spermatozoa to silver nanoparticles, obtained by reducing xylose and borohydride, induced significant secondary changes in the morphological structure of male reproductive cells. These findings indicate the potential reproductive toxicity of silver nanoparticles.

Growth traits belong to the most important economic traits in livestock. One of the genes involved in vertebrate growth and development is insulin-like growth factor 1 (IGF1). Therefore, in our study we hypothesised that within the sequence of rabbit IGF1 gene it is possible to identify a polymorphism that may influence growth, carcass or meat traits in rabbits. We identified 6 polymorphisms (g.89259430T>C; g.89259338C>G; g.89259328T>C; 89210029A>G; 89210349C>G and g.89194199C>T) within introns of the IGF1 gene. One polymorphism, g.89194199C>T, was analysed using polymerase chain reaction high-resolution melting (PCR-HRM). We performed the association analysis on 370 animals (males to females 1 : 1) of different breeds: New Zealand White × Flemish Giant crossbreds (NZW × FG), Termond White (TW) and Flemish Giant (FG). Results showed that for growth and slaughter traits in TW populations a significant association (P = 0.003) was found for slaughter weight (SW) when CT genotypes showed significantly higher values compared to CC genotypes (2 878.0 g ± 107.0 and 2 678.0 g ± 34.0, respectively). For TW rabbits we found a significant association (P = 0.009) for dissected bone weight in hind leg (HB) when CT genotypes (127.0 g ± 5.8) had significantly higher values compared to CC genotypes (112.0 g ± 2.4). For carcass traits and physical characteristics of meat we found for musculus longissimus lumborum in TW rabbits that the b* parameter value 45 min after slaughter was significantly higher (P = 0.001) for CT genotypes (1.88 ± 0.05) compared to CC genotypes (0.05 ± 0.02). We conclude that the use of identified SNP in breeding may be limited to some breeds.

The growing production and use of silver nanoparticles continues to raise questions about their consequences for human and animal health. The method of production, particle stabilization, particle size, concentration, and duration of exposure to cells can affect their reactivity and, consequently, their toxicity. This study was conducted to determine the degree of harmfulness of colloidal silver compounds, including silver nanoparticles produced via the HVAD method, to mitotic chromosomes in chinchilla’s cells. Thanks to the sister chromatid exchange (SCE) test, chromosome damage during cell division, i.e., the actual toxic effect of the tested compounds, could be assessed. For this purpose, whole peripheral blood from chinchillas was exposed in vitro to three colloidal silver compounds (unstable AgNP-HVAD, sodium citrate-stabilized silver nanoparticles—[AgNP+C], and silver nitrate) for 3, 6, and 24 h. The toxicity of these compounds was assessed at concentrations of 5, 10, and 20 µg/L and the occurrence of sister chromatid exchanges on chromosomes, resulting from double-strand DNA breaks, was analyzed. The studies revealed a notable increase in SCEs compared to the control group, suggesting the genotoxic properties of the examined AgNPs. The highest level of chromosome damage was observed following exposure to citrate-stabilized silver nanoparticles. Further research is needed to better understand the toxicological mechanisms of AgNPs produced via the HVAD method and their effects on mammalian somatic cells.

The aim of the study was to estimate genetic parameters of 6 descriptive and 21 linear conformation traits in Simmentals. The data were obtained from FedInfo, the Polish national recording system, and were provided by the Polish Federation of Cattle Breeders and Dairy Farmers. A multi-trait animal model and a Bayesian method via Gibbs sampling (BLUPf90 package) were used to estimate the genetic parameters of 6 descriptive and 21 linear conformation traits. The analysis included 1.397 recorded Simmental cows and one generation of ancestors, totaling 2.330 individuals. The cows, born between 2007 and 2017, were daughters of 115 sires. The heritability of descriptive traits was low to high and ranged from 0.09 for feet-and-legs to 0.55 for muscularity. Among the linear traits, the highest heritability was estimated for chest circumference (0.69), front-muscularity (0.61) and rear-muscularity (0.60). Traits related to legs were lowly heritable. Descriptive traits showed moderate to high genetic correlations; all were positive and ranged from 0.23 to 0.86. The lowest genetic correlations were estimated between udder and muscularity (0.23), whereas the highest between overall conformation and both udder (0.85) and muscularity (0.86). Among the linear traits the highest genetic correlations occurred between chest circumference and chest width (0.84), front-muscularity (0.88) and rear-muscularity (0.80), as well as between chest width and both front-muscularity (0.84) and rear-muscularity (0.82). Front-muscularity and rear-muscularity were also highly genetically correlated (0.89).

This study estimated the impact of main founders and ancestors on inbreeding subdivision in the Polish Simmental cattle population. Two reference populations were defined: subset A (20,827 cows born 1984–2009) and subset B (19,554 cows born 2010–2020). Ancestral inbreeding coefficients were calculated relative to the main founders and ancestors for all cows in both subsets. Significant changes in ancestor composition were observed in younger cows. The main founders with the highest genetic contribution numbered 10 in subset A and 7 in subset B, with 7 common to both. Main ancestors numbered 11 (all bulls) in subset A and 15 in subset B, with 6 shared between subsets. The frequency of occurrence of common founders in subset B ranged from 42% to 49%, while that of common ancestors ranged from 31% to 68%. Kalinowski’s new inbreeding coefficient was six times higher in subset B than in subset A. Although overall inbreeding levels remained low, the proportion of cows with elevated inbreeding increased over time despite continuous importation of breeding animals. These findings suggest that breeders should scrutinize more carefully the pedigrees of imported animals to prevent further inbreeding accumulation.