Circulating microRNA Profiles during the Bovine Oestrous Cycle

Up to 50% of ovulations go undetected in modern dairy herds due to attenuated oestrus behavior and a lack of high-accuracy methods for detection of fertile oestrus. This significantly reduces overall herd productivity and constitutes a high economic burden to the dairy industry. MicroRNAs (miRNAs) are ubiquitous regulators of gene expression during both health and disease and they have been shown to regulate different reproductive processes. Extracellular miRNAs are stable and can provide useful biomarkers of tissue function; changes in circulating miRNA profiles have been reported during menstrual cycles. This study sought to establish the potential of circulating miRNAs as biomarkers of oestrus in cattle. We collected plasma samples from 8 Holstein-Friesian heifers on days Days 0, 8 and 16 of an oestrous cycle and analysed small RNA populations on each Day using two independent high-throughput approaches, namely, Illumina sequencing (n = 24 samples) and Qiagen PCR arrays (n = 9 sample pools, 3-4 samples / pool). Subsequently, we used RT-qPCR (n = 24 samples) to validate the results of high-throughput analyses, as well as to establish the expression profiles of additional miRNAs previously reported to be differentially expressed during reproductive cycles. Overall, we identified four miRNAs (let-7f, miR-125b, miR-145 and miR-99a-5p), the plasma levels of which distinctly increased (up to 2.2-fold, P < 0.05) during oestrus (Day 0) relative to other stages of the cycle (Days 8 and 16). Moreover, we identified several hundred different isomiRs and established their relative abundance in bovine plasma. In summary, our results reveal the dynamic nature of plasma miRNAs during the oestrous cycle and provide evidence of the feasibility of using circulating miRNAs as biomarkers of reproductive function in livestock in the future

Evaluation of the relationship between youth entrepreneurship and emigration intentions: theoretical-methodological aspects

Purpose – the purpose of this article is to investigate the relationship between youth entrepreneurship and emigration attitudes by presenting a method for evaluating the link between youth participation in entrepreneurship promotion initiatives, entrepreneurship and emigration attitudes, and also to check its validity. Research methodology – the quantitative test method presented in the article consists of 3 key parts that have their own specifics of evaluation and different methodologies. Findings – the results of the study did not show the correlation between the analyzed elements. Research limitations – although a method test made it possible to verify its suitability, a more representative sample of respondents is needed to provide valid results about the correlation of above mentioned 3 elements. Practical implications – based on the methodology evaluated, everyone familiar with the material will be able to initiate surveys and/or scientifically based researches at a different territorial level on youth entrepreneurship and emigration intentions and to evaluate the extent of the youth involvement in entrepreneurship promotion initiatives and its relationship with the entrepreneurial spirit of the individual. Originality/Value – this study contributed to the existing research on entrepreneurship, supplementing it with new insights on the existence of a relation between entrepreneurship promotion, entrepreneurship, and the tendency to emigrate, which, as far as the authors are aware, was researched neither in Lithuania nor globally

The importance of the periconception period : immediate effects in cattle breeding and in assisted reproduction such as artificial insemination and embryo transfer

In livestock breeding, the successful outcome is largely depending on the "periconception environment" which, in a narrow sense, refers to the genital tract, where gametogenesis and embryogenesis occur. During these early stages of development, gametes and embryos are known to be particularly sensitive to alterations in their microenvironment. However, as the microenvironment somehow reflects what is going on in the external world, we must widen our definition of "periconception environment" and refer to all events taking place around the time of conception, including metabolic state and health and nutrition of the dam. In modern dairy cows that have to manage an optimal reproductive performance with continued growth and high milk yield, the periconception period is particularly challenging. The metabolic priority for growth and lactation is known to generate adverse conditions hampering optimal ovarian function, oocyte maturation, and development of embryo/fetus. In addition, by using artificial reproductive technologies (ARTs), gametes and/or embryos of livestock are exposed to unnatural conditions outside the male and female genital tract. Artificial insemination, the most widely used technique, is currently yielding pregnancy rates similar to natural mating, and calve