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This research sought to determine the effect of selected milk protein polymorphisms on the reproduction parameters of 598 black and white Polish Holstein-Friesian cattle. The analyzed genes were kappa-casein (CSN3) and beta-lactoglobulin (BLG). The following reproductive indexes were selected: the age at first calving, the interpregnancy period, the calving interval, and the insemination index. The influence of the identified genotypes on the course of parturition in cows was also analyzed. Source data were collected for each cow from the beginning of the herd life and reproduction to its culling from the herd or the end of its third lactation. Data on the age at first calving, the amount of semen portions for artificial insemination (insemination index), the interpregnancy period, and the calving interval for each cow were also collected. A contingency analysis was performed through contingency tables using a Pearson's chi-squared test for each CSN3 and BLG genotype. The results show that the BB genotype of the kappa-casein gene was associated with the most favorable values of reproductive indicators. In the case of the calving interval, the values were significantly more favorable than those of other genotypes (p ≤ 0.05). No effect of beta-lactoglobulin polymorphism on the analyzed reproductive indices was observed. On the other hand, in the case of the interpregnancy period, significant statistical differences were obtained between the AA and BB genotypes. The analyzed kappa-casein and beta-lactoglobulin genotypes did not significantly influence the course of parturition in cows. To conclude, the genotype polymorphism BB CSN3 is the most favorable for the performance of the cows in the examined herd.

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The main problem in dairy herds is reproductive disorders, which are influenced by many factors, including temperature. Heat stress reduces the quality of oocytes and their maturation through the influence of, e.g., mitochondrial function. Mitochondria are crucial during oocyte maturation as well as the process of fertilization and embryonic development. Disturbances related to high temperature will be increasingly observed due to global warming. In present studies, we have proven that exposure to high temperatures during the cleaving of embryos statistically significantly (at the level of p < 0.01) reduces the percentage of oocytes that cleaved and developed into blastocysts eight days after insemination. The study showed the highest percentage of embryos that underwent division in the control group (38.3 °C). The value was 88.10 ± 6.20%, while the lowest was obtained in the study group at 41.0 °C (52.32 ± 8.40%). It was also shown that high temperature has a statistically significant (p < 0.01) effect on the percentage of embryos that developed from the one-cell stage to blastocysts. The study showed that exposure to a temperature of 41.0 °C significantly reduced the percentage of embryos that split relative to the control group (38.3 °C; 88.10 ± 6.20%). Moreover, it was noted that the highest tested temperature limits the development of oocytes to the blastocyst stage by 5.00 ± 9.12% compared to controls (33.33 ± 7.10%) and cleaved embryos to blastocysts by 3.52 ± 6.80%; the control was 39.47 ± 5.40%. There was also a highly significant (p < 0.0001) effect of temperature on cytoplasmic ROS levels after 6 and 12 h IVM. The highest level of mitochondrial ROS was found in the group of oocytes after 6 h IVM at 41.0 °C and the lowest was found in the control group. In turn, at 41.0 °C after 12 h of IVM, the mitochondrial ROS level had a 2.00 fluorescent ratio, and the lowest in the group was 38.3 °C (1.08). Moreover, with increasing temperature, a decrease in the expression level of both LC3 and SIRT1 protein markers was observed. It was proved that the autophagy process was impaired as a result of high temperature. Understanding of the cellular and molecular responses of oocytes to elevated temperatures will be helpful in the development of heat resistance strategies in dairy cattle.

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Endocrine-disrupting chemicals (EDCs) are common in the environment and in everyday products such as cosmetics, plastic food packaging, and medicines. These substances are toxic in small doses (even in the order of micrograms) and enter the body through the skin, digestive or respiratory system. Numerous studies confirm the negative impact of EDCs on living organisms. They disrupt endocrine functions, contributing to the development of neoplastic and neurological diseases, as well as problems with the circulatory system and reproduction. EDCs affect humans and animals by modulating epigenetic processes that can lead to disturbances in gene expression or failure and even death. They also affect steroid hormones by binding to their receptors as well as interfering with synthesis and secretion of hormones. Prenatal exposure may be related to the impact of EDCs on offspring, resulting in effects of these substances on the ovaries and leading to the reduction of fertility through disturbances in the function of steroid receptors or problems with steroidogenesis and gametogenesis. Current literature indicates the need to continue research on the effects of EDCs on the female reproductive system. The aim of this review was to identify the effects of endocrine-disrupting chemicals on the female reproductive system and their genetic effects based on recent literature.

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The aim of this review is to comprehensively present disorders of the reproductive system in cattle exposed to contact with toxic metals. Toxic metals are a common environmental pollutant and can come from mines, smelters, fossil fuel combustion, or volcanic eruptions. Metals have the ability to bioaccumulate in living organisms, thus contaminating the food chain and may pose a threat to humans. They accumulate mainly in the liver and kidneys, but also in muscles and fat tissue. Toxic metals such as lead (Pb), arsenic (As), mercury (Hg), and cadmium (Cd) have a negative impact on the fertility of animals; they can lead to abortions, premature calving, or oocyte dysfunction. Moreover, in the male reproductive system, they disrupt spermatogenesis, and cause apoptosis of sperm and oxidative damage. The main source of exposure of livestock to toxic metals is through the consumption of feed or contaminated water. It is important to monitor the level of heavy metals in animal products to prevent human poisoning. Toxic metal biomonitoring can be performed by testing urine, blood, milk, plasma, or hair. Chromium (Cr), arsenic (As), and cadmium (Cd) are excreted in the urine, while lead can be detected by examining the blood of animals, while in milk, arsenic (As), cadmium (Cd), nickel (Ni), and lead (Pb) can be detected. Moreover, toxic metals do not biodegrade in the environment. To purify soil and waters, remediation methods, e.g., biological or chemical, should be used.

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African Swine Fever (ASF) is a highly contagious disease that affects the domestic pig and wild boar population. The aim of this study was to describe the introduction and spread of the ASF virus in Western Europe (1960⁻1995) and in Eastern Europe (2007⁻2018), with particular emphasis on the current ASF situation in Poland and its challenges and future perspectives. The first ASF outbreak in Europe was reported in Portugal in 1957, with the virus spreading over most of Western Europe over the next 30 years. In Eastern Europe, the virus was first observed in Georgia in 2007, from where the disease spread quickly to other neighboring countries, reaching Poland in 2014. Since then, there have been 3341 confirmed cases in the wild boar population in Poland. Although there have been no confirmed cases of wild boars coming into contact with domestic pigs, the first notified case concerning domestic pigs was reported in July 2014. Since then, there have been a total of 213 confirmed outbreaks of ASF on Polish pig farms. Given the virulence of the ASF virus and the myriad of transmission routes across Europe, the monitoring of this disease must be a priority for Europe.

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The Merino sheep represents the most prevalent sheep breed in Poland and is one of the most genetic-stable sheep races. Therefore, the aim of the study was to determine the responses of Polish Merino sheep to three thermal conditions: thermoneutral (16.5 degrees C, group I), mild heat stress (30 degrees C, group II), and severe heat stress (50 degrees C, group III). During the experiment heart rate (HR; beats/min), respiratory rate (RR; breaths/min), rectal temperature (RT) and skin temperatures (ST) were measured daily. The ST measured at four points of the animal body was mostly statistically different (p < 0.01) between the treatment groups. It was found that the highest HR occurred in group II (30 degrees C), and that it was higher than in groups I (16.5 degrees C) and III (50 degrees C) (p < 0.01 for groups I, III). The RR was different (p < 0.01) in all experimental groups (I, II, III) with the highest increase in group II. There was also a clear and significant (p < 0.01) increase in RT during the heat stress phases. Blood analysis including morphology, biochemistry and hormones (adrenaline, noradrenaline, ACTH, and cortisol) was also performed. Significant differences in cortisol level in group II (p < 0.01) and group III (p < 0.05) were observed. There was an upward trend in adrenaline and ACTH as a result of increasing temperature. Differences in noradrenaline levels (p <0.01), with the highest level recorded in group III, were also observed. Additionally there was a strong upward trend in blood parameters, especially in hormone concentrations (cortisol, noradrenaline).

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