Fernando Moreira da Silva

The use of frozen-thawed (FT) boar sperm is essential for the swine industry, as it provides global access to superior genetics, thereby increasing efficiency and profitability. However, the cryopreservation process causes cellular damage, reducing post-thaw sperm quality and fertility, and often resulting in smaller litter sizes. This study evaluated the protective effect of conjugated linoleic acid (CLA; 10 trans, 12 cis-CLA) in freezing extenders on boar sperm quality and in vivo fertility. Semen from three boars was cryopreserved in two groups: a control and a CLA-supplemented group. Post-thaw sperm quality, including membrane stability and acrosomal integrity, was assessed using flow cytometry. Fertility was tested by inseminating 24 sows with either fresh or frozen-thawed semen, recording pregnancy rates and litter sizes. CLA supplementation significantly improved post-thaw sperm membrane integrity and acrosomal preservation, indicating enhanced resilience to osmotic and oxidative stresses. Notably, sows inseminated with CLA-treated semen showed increased total and live-born litter sizes. These findings suggest that CLA acts as a potent cryoprotective additive, likely by stabilising the sperm plasma membrane and mitigating lipid peroxidation. CLA appears to be a promising agent for improving swine artificial insemination programs; however, large-scale studies are still required to confirm its efficacy under commercial conditions.

Oxidative stress has a negative impact on semen quality. Sperm handling and storage raise the probability of oxidative stress in cattle production. Therefore, there is a need to develop methods that can optimize sperm quality, especially when it is cryopreserved. The objective of this article was to analyze existing information on the current advances for the improvement of bovine semen quality and resistance to oxidative stress through antioxidants. Detailed research was conducted on oxidative stress, resveratrol, melatonin, quercetin, nanoparticles, glutathione, vitamin E, and their relation to bovine semen. A diversity of articles and publications from 2019 to 2025 was selected from different scientific journals. The search platforms used were PubMed and Scopus. The quality of the materials used was evaluated thoroughly, with the quality of the journals and websites classified between Q1 and Q2 according to the Scimago Journal and Country Rank. Improvement of semen parameters was shown to be possible with antioxidant supplementation through diet and semen extenders. Currently, the most researched antioxidants are resveratrol and melatonin. The application of nanotechnology in semen extender supplementation seems to be a very promising practice. The study of new combinations and strategies for semen extender supplementation will provide valuable insights, paving the way for advancements in cattle production.

The Azores is a Portuguese archipelago, located in the North Atlantic, with a subtropical climate. Its position on the Gulf Stream makes this region ideal for year-round grass-fed cattle for milk and meat production. Dairy operations in the Azores have major importance for the islands’ economy. However, these weather conditions also favor the growth of fungi in pastureland. Among them, Pseudopithomyces chartarum, formerly called Pithomyces chartarum, is one of the fungi with enormous negative economic impact for farmers, and the dairy industry in general. As in New Zealand and other regions of the world, outbreaks of pithomycotoxicosis occur in our grazing cattle, finding the need for preventive procedures, for there is no cure for the disease. This paper provides an overview of the disease and presents recent advances regarding the environmental conditions and predictability of P. chartarum sporulation based on a 2-year study with IoT temperature and humidity sensors. It will also cover prevention strategies to minimize the impact of the disease in grazing cattle. The duration of zinc supplementation as a preventive measure was reduced by approximately 40 days per year over the course of the study, indicating a more targeted and efficient management strategy.

As the European Union advances its bioeconomy strategy, the agricultural sector emerges as a key domain requiring targeted upskilling in digital and entrepreneurial competencies. This study examines how agricultural professionals perceive the importance of these competencies and identifies related training needs, drawing on the European Commission’s Digital Competence Framework (DigComp) and Entrepreneurship Competence Framework (EntreComp). Using a quantitative survey methodology, data were collected from 140 respondents, including farmers, agronomists, consultants, entrepreneurs, and policymakers, in four European countries: Greece, Italy, Portugal, and Sweden. Descriptive and non-parametric analyses (Mann–Whitney U and Kruskal–Wallis tests) revealed strong recognition of digital competencies across all groups, with significant variation by country, while perceptions of entrepreneurial competencies differed mainly by professional role. Moreover, a significant lack of formal bioeconomy-related education was identified. The findings underscore the need for targeted, competence-based education and policy interventions to equip professionals with the skills required for a sustainable and innovation-driven agricultural sector.

The present study was designed to assess the effect of stress on the reproductive performance of cattle. For this purpose, a total of 137 cows were divided into two groups: 65 belonging to the Azores Lydia breed and 72 crossing Aberdeen-Angus with Limousine, free of IBR, Chlamydia and BVD diseases and with a body condition score ranging from 2.75 to 4.0. Eight days before starting the experimental procedures, animals passed through the containment sleeve every other day for routine and human presence. For the synchronization protocol, a progesterone-impregnated controlled internal drug release (CIDR®) insert was placed intravaginally, and an injection of GnRH was given. After 7 days, PGF2α was administered, and the CIDR® was removed. Sixty hours after removal, cows were inseminated once after another injection of GnRH to induce ovulation, and pregnancy diagnosis was performed by ultrasonography 30 days after artificial insemination. Peripheral blood was collected in 5 ml tubes with a Z Serum Sep Clot Activator, and cortisol was measured using the IMMULITE 2000 Immunoassay System ®. Our results indicated significant differences (p≤0.05) in the cortisol levels among both groups (beef crossbred cows vs Azores Lydia) of 4.3±0.3 ng/dl and 5.8±0.4 ng/dl, respectively. The pregnancy results were also significantly different: 63.7% vs 45.6%, respectively, for beef crossbred and "Azores Lydia" cows. The present study clearly demonstrated a negative correlation between cortisol levels and pregnancy rates after fixed-time artificial insemination. The low levels of cortisol observed in the animals and particularly in the Azores Lydia breed, when compared to other studies carried out on these animals, must be due to the passage of the animals in the sleeve, allowing them to habituate to a routine, as well as to human presence.

In vitro maturation (IVM) is one of the most important steps in in vitro embryo production (IVEP). It is a complicated procedure in which nuclear and cytoplasmatic changes in oocytes appear. In order to carry out the in vitro maturation procedure correctly, it is necessary to provide the oocytes with as close to a natural (in vivo) environment as possible. Many factors contribute to the overall poor quality of in vitro-matured oocytes. One important factor may be oxidative stress (OS). The generation of oxidants, such as reactive oxygen species, is common under culture conditions. The solution for OC treatment and prevention is antioxidants. In the last 5 years, many studies have examined different antioxidants and their effects on in vitro maturation of oocytes and embryo production. The aim of this systematic review was to present the achievements of scientific research in the last five years, in which the effects of many antioxidants were tested on bovine oocyte maturation and embryo production.

Effects of the surfactant Sodium Dodecyl Sulfate (SDS) on the motility and viability of boar semen after thawing were evaluated. For such purpose, semen of twelve adult boars was collected twice a week, the rich portion of this semen was separated and frozen with different concentrations of SDS (0; 2.5; 5; 10; 20 and 40 mM). For freezing the semen was subjected to a cooling curve in an Ice Cube Freezer with a programmed curve as follows: From 5 to -5°C to -6°C/min, from -5 to -80 to -40°C/min in which semen was for 30 minutes. From -80 to -150 semen was cooled at a slope of -60°C/min being then plunged in liquid nitrogen. After collecting, before and after freezing/thawing, semen was evaluated for pH, cell concentration, viability and motility, as well as the percentage of normal sperm cells and agglutination level. Results indicated that before freezing sperm quality obtained from the different boars was always alkaline and very similar among boars. On average, pH was 7.50±0.27 ranging from 7.05 to 7.79 Viability, motility and agglutination level was respectively 62.7±9.9%: 4.8%±0.3 and 9.3%±1.82. After thawing, the best sperm quality was obtained when the semen was frozen with an SDS concentration of 0.2% W/V, in which values of viability reached 30.1% (±3.7). Based on the results one can conclude that SDS can be used to preserve boar semen for long periods, retaining semen quality after thawing.

The aim of the present study was to evaluate the effect of three different freezing curves on male goat’s sperm viability and acrosome integrity. Semen was collected on three adult male goats in February (Azores, Portugal, latitude 38°39′N) using an artificial vagina and a female with induced heat. Three collection sessions were spaced of approximately 5 days. The study followed a factorial design of repeated measurements. After volume, sperm concentration and mass motility evaluation, live and dead spermatozoa (spz) were counted and acrosome integrity was evaluated by Flow Cytometry (FCM). In the meantime semen was frozen using three curves differing in the second cooling ramp rate (curve A = 25°C/min, curve B = 35°C/min and curve C = 45°C/min). After thawing, the percentage of live/dead sperm cells and the acrosome integrity were determined by FCM, using respectively Propidium Iodide (PI) and Pisum Sativum Agglutinin conjugated to Fluorescein Isothiocinate (FITC-PSA). By combining these two fluorochromes, the thawed semen was divided into: Live sperm with intact acrosome, unstained PI and unstained FITC-PSA (LL); live sperm with damaged acrosome, unstained PI and stained FITC-PSA (LR); dead sperm with intact acrosome, stained PI and unstained FITC-PSA (UL); dead sperm with damaged acrosome, stained PI and stained FITC-PSA (UR). Although different freezing curves did not significantly influence live sperm rate with intact (19.14±0.86% spz curve A, 17.72±0.86% spz curve B and 18.18±0.86% spz curve C) or damaged (0.44±0.04 % spz curve A, 0.38±0.04% spz curve B and 0.49±0.04% spz curve C) acrosome, a significant (P<0.05) effect of animals was observed in the four parameters studied. Regarding the percentage of LL spermatozoa, buck 1 presented values lower (P<0.05) by about 50% than bucks 2 and 3. Data also were affected significantly by the day of collection. These results strongly suggest that although goat sperm cells are not influenced by the pattern of cooling curves investigated, a considerable variability in the response of individual animals as well as the collection date may be expected.