Cortisol is a key biomarker of stress and hypothalamic-pituitary-adrenal (HPA) axis activity in an organism. Different biological samples are used for measuring cortisol levels, such as blood, saliva, milk, urine, faeces, and hair. Blood plasma or serum cortisol measurements are widely applied to quantify acute stress response in farm animals, but stress sampling and rapid hormonal changes can undermine accuracy in results. Saliva has proven to be a reliable alternative sample for assessing free cortisol, offering a less stressful approach with minimal triggering of the stress response. Cortisol determination in milk is a non-invasive method of limited applicability for lactating ruminants, though physiological parameters such as milk yield and stage of lactation can influence its interpretation. Concentrations of cortisol in urine reflect the cumulative cortisol secretion over time, making it a valuable indicator of chronic stress, though research on small ruminants remains limited. Similarly, faecal cortisol metabolites offer a non-invasive means of assessing adrenal activity with delayed but integrated hormonal fluctuations. Hair and wool analysis provide insight into long-term stress exposure, though factors such as seasonal variation and local synthesis complicate its application. This review highlights the strengths and challenges associated with different cortisol sampling methods, emphasising the importance of multiple biological sample approaches for accurate welfare assessments in ruminants.

U ovom radu predstaviti će se jedinstvenost inovacije istraživanja provedenih u okviru HRZZ projekta “Inovativni funkcionalni proizvodi od janjećeg mesa“ (IP-2016-06-3685). Naime, uvjerenja smo da naša projektna inovacija, koja je prvenstveno rezulta...

The effects of RF-EMR from 5G on red blood cell (RBC) morphometric parameters and complete blood count (CBC) in pigs are unknown. Exposure of human and laboratory animal blood to RF-EMR from 4G and older technologies has been shown to have deleterious effects on blood cells and changes in CBC. This study aimed to determine the effect of 5G RF-EMR at different frequencies on RBC morphometry and CBC after short-term in vitro exposure of sow blood. Blood samples were taken from 16 sows aged 1 to 2 years. Three ethylenediaminetetraacetic acid (EDTA) tubes per sow were labelled as experimental tubes and three as control tubes. Experimental sam-ples were placed in a Half-cone gigahertz transversal electromagnetic cell and exposed for 2 hours to three different frequencies of 5G network, i.e. 700 MHz, 2500 MHz and 3500 MHz with an electric field strength of 10 V/m. The morphometric parameters of the erythrocytes were determined using the computer-assisted programme SFORM, while the CBC value was determined using a haematology analyser. The effect of 5G RF-EMR exposure on sow RBC morphometry in exposed blood was frequency dependent. The most detrimental effect was observed after exposure at 700 MHz, which resulted in significantly elongated and irregularly bordered sow RBCs. These results suggest that in vitro exposure of blood to 5G RF-EMR may im-pact the RBCs shape, as well as their mechanical properties or integrity, which could have serious effects on cell function.