Oxidative stress as a leading factor of male infertility requires correction with modern pharmacological agents, particularly redox-active nanoparticles, to improve sperm quality and hormonal balance. The current experimental study aimed to investigate the effect of orthovanadate nanoparticles of rare earth elements, particularly Gadolinium, with pronounced redox properties on the reproductive function of male rabbits under oxidative stress. A total of 36 mature male Hyla rabbits were divided into three groups of intact control (n = 12) and two experimental groups, including rabbits ubder oxidative stress (n = 12), induced by the introduction of tert-Butyl hydroperoxide, and those under oxidative stress plus hydrosol of gadolinium orthovanadate nanoparticles (NPs, n = 12) intake for 14 days. There were four rabbits per three replicates in each group. Animals of all groups were kept on the same diet and had free access to water. The use of NPs led to an improvement in sperm quality indicators. There was an improvement in motility and ejaculate volume indicators (by 14.6% and 39.2%, respectively), a reduction of the content of morphologically abnormal sperm by 26.7%; normalization of sex hormones, an increase in the level of total testosterone (by 113%) with a decrease in 17-β-estradiol (by 16.5%). This sex hormones improvement led to an increase in the androgen saturation of the rabbit’s body (free androgen index at the end of the experiment was 36.5%). The obtained changes were accompanied by a decrease in the oxidative load, as evidenced by a reduced content of diene conjugates and thio-barbituric acid-reactive compounds in the blood serum of rabbits by 30.4% and 26.8%, compared to the control. At the same time, there was an increase in the antioxidant potential, especially its glutathione link – the activity of glutathione peroxidase and glutathione reductase (by 42.5% and 34.2%, respectively), and the content of reduced glutathione increased by 62.3%, compared to the indicators before the introduction of NPs. The results of the study confirmed the effectiveness of using gadolinium orthovanadate NPs to correct the reproductive function of males under oxidative stress.

Failure of passive immunity transfer is one of the main causes of increased susceptibility to infectious agents in newborn kids. To ensure successful transfer of passive immunity, kids need to be fed high-quality colostrum, containing an adequate concentration of IgG. This work evaluated the quality of colostrum obtained in the first 3 days postpartum from Malagueña dairy goats. The IgG concentration in colostrum was measured using an ELISA as a reference method, and it was estimated by optical refractometer. Colostrum composition in terms of fat and protein was also determined. The mean concentration of IgG was 36.6 ± 2.3 mg/mL, 22.4 ± 1.5 mg/mL and 8.4 ± 1.0 mg/mL on days 1, 2 and 3 after parturition, respectively. Brix values obtained using the optical refractometer were 23.2%, 18.6% and 14.1% for days 1, 2 and 3, respectively. In this population, 89% of goats produced high-quality colostrum with IgG concentrations of >20 mg/mL on the day of parturition, but this percentage declined dramatically over the following 2 days. The quality of the fresh colostrum estimated with the optical refractometer was positively correlated with those obtained using ELISA (r = 0.607, p = 0.001). This study highlights the importance of feeding first-day colostrum to newborn kids and demonstrates that the optical Brix refractometer is suitable for the on-farm estimation of IgG content in colostrum.

Animal reproduction is one of the main factors limiting the efficiency of livestock production. Its optimal level is possibly achieved when certain conditions are created for animals. As reproduction is a complex reflex process depending on neuroendocrine regulatory mechanisms, the character and strength of stimuli, which, in turn, is due to a number of factors. Under normal conditions, the body of animals is affected by many different factors, which are appropriately transformed and specified by positive or negative reactions. Inhibitory factors include air pool, saturated with harmful substances and gases, ionizing radiation, poor water quality along with altered redox properties, hypokinesia combined with poor unbalanced feeding, systematic chronic stress, presence of toxic substances in feed, and the deficiency of vitamins and other bioantioxidants in feed or their excessive spending. Of the wide range of genetic and paratypic factors of negative impacts on reproductive capacity, the most common one is alimentary, which causes impaired reproductive function due to deficiencies in the rules, regulations, and feeding regime of animals. In particular, the alimentary can be associated with both general malnutrition (starvation) and overfeeding (obesity). However, the alimentary form of infertility mostly occurs due to low-quality diets when the diet lacks vital components (mainly vitamins, macro-, and micronutrients) or the quantitative ratios of the ingredients are violated. This is possible even if the total nutritional value of the diet meets the established requirements for the physiological needs of the body. Vitamins, micro-, and macronutrients are ecologically deficient factors of disturbance of animal reproductive function, the influence of which is observed on all processes of reproduction, from fertilization to the postpartum period and the preservation of young animals. The pathogenesis of their insufficiency is associated with the violation of steroido-, gameto-, and embryogenesis and the emergence of ante-, intra-, neo- and postnatal pathologies, respectively. Therefore, treatments and prevention measures should be aimed at providing animals with biologically complete balanced feeding and replenishment of the body with vitamins and minerals. However, all these issues remain incompletely studied and need further research.

Fatty acids (FA) have a variety of functions in animal bodies. They can be used as metabolic biomarkers, including in pathological conditions. Heat stress (HS) is accompanied by a drop in productivity in dairy cows, resulting from a negative energy balance (NEB), impaired biochemical processes in the body and suppressed immune system. The paper describes the role of individual FAs, the changes in content and ratio of which in serum and milk can be used to assess the physiological state or to predict HS in dairy cows. The purpose of the review has been to show the prospects in the study of the fatty acid composition of biological fluids (blood and milk) to assess the clinical status of dairy cows under HS and the consequences of the possible impact of heat on dairy product quality. Dietary strategies to correct the body's clinical status through dietary FAs have also been mentioned in this literature review.

Heat stress (HS) is a critical environmental factor that disrupts the hormonal balance of animals by activating and subsequently suppressing the hypothalamic-pituitary-adrenal (HPA) axis. This process alters cortisol secretion, a key stress hormone involved in maintaining homeostasis, regulating metabolism, and facilitating adaptation to adverse conditions. This study investigates the impact of HS on the hormonal responses of Holstein and Brown Swiss dairy cows, with a specific focus on cortisol as a principal biomarker of stress adaptation. The research was conducted under conditions of acute and chronic HS of moderate intensity. Cows were divided into control (CON) and experimental (HYP) groups. Serum cortisol levels were assessed while accounting for the temperature-humidity index (THI), lactation number, days in milk, and energy-corrected milk yield. Cortisol concentrations were measured in blood serum with using an electrochemiluminescence immunoassay method (ECLIA). The findings revealed that cows in the experimental groups experienced significantly higher daily temperatures and THI compared to the control groups. Holstein cows were subjected to chronic HS for 45 days, with a mean THI of 77.5, while Brown Swiss cows experienced acute HS for 5 days, with a mean THI of 77.6. Serum cortisol levels were significantly lower in the experimental groups: 27.25 ± 2.92 nmol/L versus 39.45 ± 3.26 nmol/L (a 30% decrease) in Holstein cows and 11.6 ± 0.54 nmol/L versus 24.5 ± 8.85 nmol/L (a 52% decrease) in Brown Swiss cows (p < 0.05), indicating a suppressive effect of HS on the HPA axis. These results highlight the importance of breed-specific differences in stress responses and underscore the role of cortisol as a key indicator of adaptive mechanisms. The observed reduction in cortisol concentrations suggests potential effects of HS on metabolic stability and resilience to environmental stressors.

Studies have shown that the use of herbal feed additives «Fitopank» by Grey Ukrainian cows 30 days before calving had a positive effect not only on the body of cows-mothers and the quality of their colostrum, but also on the physiological state of the born calves and the growth energy of young animals. Adding of «Fitopank» to the cows diet helped to improve the quality of colostrum and its immunological value. It showed a probable increase of total protein by 10–14 % (P < 0.05) and immunoglobulin level by 23–25 % (P < 0.01). The titratable acidity of both the first and second milk yields was 16 % lower (P < 0.01) than in the control group. The use of this feed additive improved the immunological status of newborn calves. In their blood there was an increase of total protein content by 17 % (P < 0.05), the level of gamma globulins by 18% (p < 0.05), IgG concentrations by 14 % (p < 0.05), Ig M by 13 % and Ig A by 17 % (p<0.05), as well as the growth of T-lymphocytes by 46% and B-lymphocytes by 24 % (p < 0.01), compared with control group. Detected increased growth of the 8–12 months bulls (by 2.3%, p < 0.05) of the experimental group may indicate their tendency for better development of meat qualities. Experiment showed that the absolute live weight increase of young animals up to 18 months was higher than the control by 10.9 kg (p < 0.05). The study of the herbal supplements efficacy for the prevention and treatment of animals immunodeficiency, as well as their impact on the metabolic processes and productive qualities of farm animals will be the focus of our further research. Встановлено, що застосування кормової фітодобавки «Фітопанк» коровам сірої української породи за 30 діб до отелення мало позитивний вплив не тільки на організм корів-матерів та якість їх молозива, а й на фізіологічний стан отриманих від них телят та енергію росту молодняку. Виявлено, що додавання до раціону Фітопанку сприяло підвищенню якості молозива та його імунологічної повноцінності. У ньому відбувалося вірогідне зростання загального білка – на 10–14 % (P < ,05) та рівня імуноглобулінів – на 23–25 % (P < 0,01). Титрована кислотність як першого, так і другого удою була меншою на 16 % (P < 0,01), ніж у контролі. З’ясовано, що використання кормової фітодобавки поліпшувало імунологічний статус новонароджених телят. В їх крові відмічалося підвищення вмісту загального білка – на 17 % (P < 0,05), рівня гаммаглобулінів – на 18 % (р < 0,01), концентрації IgG – на 14 %(р < 0,01), Ig М – на 13 % та Ig А – на 17 % (р < 0,01), а також зростання Т-лімфоцитів – на 46 % і В-лімфоцитів – на 24% (р< 0,01), порівняно з контролем. Виявлена перевага за відносною швидкістю росту в бугайців дослідної групи, порівняно з аналогами 8–12-місячного віку (на 2,3 %, p < 0,05), може свідчити про їх схильність до кращого формування м’ясних якостей. Абсолютний приріст живої маси молодняку до 18-місячного віку за впливу фітодобавки був вищим за контроль на 10,9 кг (р < 0,01). Вивчення ефективності препаратів (добавок) рослинного походження з метою попередження і лікування імунодефіцитних станів тварин, а також їх вплив на метаболічні процеси та продуктивні якості сільськогосподарських тварин будуть напрямом наших подальших досліджень.