Impaired Reproductive Performance of Dairy Cows under Heat Stress

Hot seasons of the year are accompanied by significant losses for dairy farmers. Stress in cattle breeding causes various physiological disorders of vital organs and systems, including nervous, cardiovascular, and endocrine pathologies. Heat Stress (HS) affects the reproductive performance of cows at various physiological stages (pregnancy, calving, the postpartum period) and that manifests in fertility decrease and even leads to culling. Understanding the mechanisms and effects of high temperatures on the reproductive function of productive animals will allow minimizing the impact of HS by implementing appropriate heat-reduction strategies, adjusting nutrition, and breeding heat-tolerant cattle. Thus, a well-considered and timely implemented HS control strategy will prevent reproductive losses and reduce economic losses in the dairy industry

Induction and synchronization of oestrus in sheep and goats

Different methods for oestrus induction and synchronization in domestic small ruminants have been developed. Seasonality and female’s status are important factors for choosing the most appropriate treatment. In the case of females during breeding season, prostaglandins can be used since functional corpus luteum must be present in the ovaries, while during non-breeding season females should be treated with progesterone-based treatments, accompanied by equine chorionic gonadotrophin (eCG), releasing hormones and other compounds. Significant spread of oestrus synchronization during and after the breeding season has been achieved by the use of intravaginal sponges impregnated with synthetic analogues of progesterone. However, the effect of hormonal drugs on the female reproductive system may manifest differently depending on the initial functional state of reproductive organs and the hormonal status, and negative consequences can be observed when drugs are wrongly administered. In addition, insufficient knowledge about the patterns of change in the reactivity of the nervous sexual centers and the corresponding reactions of the body to the administration of hormones reduces their effectiveness, which limits the widespread use. In general, the induction and synchronization of oestrus in small ruminants is an currently important direction of scientific research and an urgent problem of sheep and goat breeding, but the proposed methods require further improvement by reducing the costand increasing biosecurity and predictability of the result

Učinkovitost sustava automatske detekcije tjeranja u junica smeđeg goveda kada se rabi seksirano sjeme na velikoj farmi mliječnih goveda

The identification of cows and heifers in heat and their timely artificial insemination (AI) is an important issue for large dairy units. The objective of the research was to study the efficiency of insemination of oestrous Brown Swiss heifers using am automated heat detection system (AHD) compared to heat detection by visual observation (VO). The AHD system application increased the fertility of heifers by 8.9% when using conventional semen (unsexed) and by 14.4% using sexed semen. The number of services per conception when using sexed semen decreased from 3.7±1.08 with VO to 2.4±0.68 with AHD. Two-factor analysis of variance showed that an 89% effect of managerial decisions such as the detection of heifers in heat by means of AHD and the use of sexed semen on the efficiency of insemination. This study showed that professional breeders and veterinarians should pay particular attention to AI management when making these managerial decisions in large dairy units.Identifikacija krava i junica koje se tjeraju i njihovo pravovremeno umjetno osjemenjivanje (AI) predstavljaju problem za velike mliječne farme. Cilj je ovog istraživanja bio ispitati učinak osjemenjivanja junica smeđeg goveda u estrusu uporabom sustava automatske detekcije tjeranja (AHD) u usporedbi s detekcijom tjeranja vizualnim promatranjem (VO). Primjena AHD sustava povećala je plodnost junica za 8,9 % kod uporabe konvencionalnog (neseksiranog) te za 14,4 % kod uporabe seksiranog sjemena. Broj umjetnog osjemenjivanja po začeću prilikom uporabe seksiranog sjemena spustio se s 3,7±1,08 s VO na 2,4±0,68 uporabom AHD sustava. Analiza dvaju čimbenika odstupanja pokazala je da je učinak upravljačkih odluka poput detekcije junica koje se tjeraju pomoću AHD-a i uporaba seksiranog sjemena na učinkovitost osjemenjivanja bio 89 %. Ova studija pokazala je da bi profesionalni uzgajivači i veterinari posebnu pozornost trebali posvetiti upravljanju umjetnim osjemenjivanjem u provedbi tih upravljačkih odluka na velikim mliječnim farmama

Impaired Reproductive Performance of Dairy Cows under Heat Stress

Hot seasons of the year are accompanied by significant losses for dairy farmers. Stress in cattle breeding causes various physiological disorders of vital organs and systems, including nervous, cardiovascular, and endocrine pathologies. Heat Stress (HS) affects the reproductive performance of cows at various physiological stages (pregnancy, calving, the postpartum period) and that manifests in fertility decrease and even leads to culling. Understanding the mechanisms and effects of high temperatures on the reproductive function of productive animals will allow minimizing the impact of HS by implementing appropriate heat-reduction strategies, adjusting nutrition, and breeding heat-tolerant cattle. Thus, a well-considered and timely implemented HS control strategy will prevent reproductive losses and reduce economic losses in the dairy industry

Cows Postpartum Polymorbid Pathology

The postpartum period is one of the most important moments in a female's life. During this period caused by pregnancy and childbirth involutional changes in the reproductive system and the body as a whole occurs, which plays a crucial role in restoring reproductive function and milk productivity of cows. In this regard, the puerperium is the basis for structural and functional disorders in individual organs and systems, the disposition for the development of pathological processes and the negative impact on the reproduction of the herd, impaired fertility, calf yield and milk productivity. Diseases during the postpartum period in cows have species and age polymorbidity, specific in highly productive animals and first-borns and are especially common in hypovitaminosis and trace elements. Their occurrence is associated with unsatisfactory conditions for keeping and feeding cattle, mainly in the autumn-winter and winter-spring periods of the year, especially during the stable keeping of cows. The pathogenesis is based on metabolic disorders and endocrine dysfunctions with a decrease in the body's resistance, which is complicated by the action of adverse environmental factors. Puerperal pathologies are quite common and described in the literature as individual diseases, but limited ‒ by their combination (co-, poly- and multimorbidity, multiorgan failure, multiple, complex, combined and concomitant pathology, associated and multifactorial diseases or polypathy). Options of combining postpartum pathologies are diverse with the involvement of metro- and ovariopathies, udder diseases, fallopian tubes and metabolism in the form of inflammatory processes and dysfunctions. The hypogonadism development on the background of chronic metritis, or endometritis complicated by ovarian dysfunction, or subclinical chronic endometritis with hypoluteolysis, salpingo-oophoritis and salpingitis is widespread. Postpartum inflammatory processes in the genitals are the cause of prolonged symptomatic infertility and are often registered in the form of acute endometritis in combination with inflammatory processes of other genitals. For example, inflammation of the endometrium in many cases is accompanied by inflammation of the mucous membrane of other parts of the genitals ‒ cervicitis, vaginitis, vestibulitis. Quite often the simultaneous course of inflammatory processes in the genitals and udder of cows, as well as pathologies of the uterus and ovaries are registered. Thus, one of the most common combined pathologies of the postpartum period in cows is acute subinvolution of the uterus with acute metritis. As a result, it should be noted that in the case of organ pathology, a combination in the form of hypogonadism-metritis, hypocalcemia-metritis, hypoluteolysis-metritis, retained placenta-metritis, ketosis-hypoluteolysis, ketosis-metritis, mastitis-metritis and uterine subinvolution-metritis, and of multiorgans – vaginitis-vestibulitis-metritis-subinvolution of the uterus-cervicitis, vaginitis-metritis-cervicitis, hypocalcemia-ketosis-metritis, hypoluteolysis-ketosis-metritis, hypoluteolysis-metritis-salpingitis-salpingo-oophoritis, retained placenta-mastitis-metritis, ketosis-mastitis-metritis

Colostrum Quality Assessment in Dairy Goats: Use of an On-Farm Optical Refractometer

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