Eliza Rossi Komninou

Beef cattle in feedlot systems may develop diseases associated with endotoxin release, such as lipopolysaccharide (LPS). However, few studies have evaluated experimental acute endotoxemia in beef heifers. Therefore, this study aimed to evaluate the effects of LPS-induced inflammation on biochemical and leukogram parameters in feedlot beef heifers. Sixteen beef heifers were randomly assigned to two groups: the LPS group (n = 8), which received two intravenous doses of 0.5 μg/kg BW Escherichia coli LPS (O111:B4) administered with a 24-hour interval between injections, and the control group (CTR, n = 8), which received two intravenous doses of saline solution. Body temperature was measured using intravaginal digital thermometers for 8 hours after the first and 12 hours after the second injection. Blood samples were collected at 0, 4, 8, 24, 28, 32, and 72 hours in relation to the first challenge, for hematological analysis and evaluation of energy and lipid metabolism, protein profile, hepatic enzymes, minerals, and inflammatory markers. Data were analyzed using a repeated measures model including group, time, and group x time interaction, with significance declared at P ≤ 0.05. LPS administration induced an increase in body temperature, a leukocytosis characterized by neutrophilia and monocytosis and a decrease in paraoxonase-1 (PON1). These findings demonstrate that experimental, acute endotoxemia induces alterations predominantly associated with the acute inflammatory response in feedlot beef heifers.

Resumo Bovinos de corte em sistemas de confinamento podem desenvolver doenças associadas à liberação de endotoxinas como, por exemplo, o lipopolissacarídeo (LPS). No entanto, poucos estudos avaliaram a endotoxemia aguda experimental em novilhas de corte. Este estudo teve como objetivo avaliar os efeitos da inflamação induzida por LPS sobre os parâmetros bioquímicos e do leucograma em novilhas de corte confinadas. Dezesseis novilhas de corte foram distribuídas aleatoriamente em dois grupos: o grupo LPS (n = 8), que recebeu duas doses intravenosas de 0,5 μg/kg de peso corporal de LPS de Escherichia coli (O111:B4), administradas com um intervalo de 24 horas entre as injeções, e o grupo controle (CTR, n = 8), que recebeu duas doses intravenosas de solução salina. A temperatura corporal foi medida utilizando termômetros digitais intravaginais por 8 horas após a primeira e 12 horas após a segunda injeção. Amostras de sangue foram coletadas em 0, 4, 8, 24, 28, 32 e 72 horas em relação ao primeiro desafio, para análise hematológica e avaliação do metabolismo energético e lipídico, perfil proteico, enzimas hepáticas, minerais e marcadores inflamatórios. Os dados foram analisados utilizando um modelo de medidas repetidas, incluindo grupo, tempo e a interação grupo x tempo, considerando significância quando P < 0,05. A administração de LPS induziu aumento na temperatura corporal, leucocitose, caracterizada por neutrofilia e monocitose, e redução da paraoxonase-1 (PON1). Esses achados demonstram que a endotoxemia aguda experimental induz alterações predominantemente associadas à resposta inflamatória aguda em novilhas de corte confinadas.

Infectious Bovine Keratoconjunctivitis (IBK) is the most prevalent ocular disease in cattle herds worldwide. The primary etiological agent is Moraxella bovis, a bacterium that adheres to the corneal epithelial cells. Due to its high contagiousness, IBK has significant impacts on animal health and welfare, as well as economic losses. The present study reports the case of a Hereford calf presenting lesions in both eyes. Upon examination, clinical signs such as keratitis, corneal opacity, corneal ulceration, and melting were detected in the left eye. In the right eye, corneal perforation was observed. Additionally, the animal exhibited progressive weight loss, impaired vision, and difficulty in locomotion and feeding. The treatment was performed topically using ophthalmic solutions containing ciprofloxacin, acetylcysteine, and homologous serum. Corneal re-epithelialization of the left eye occurred within 30 days. Subsequently, antibiotic therapy was discontinued, and treatment continued with eye drops containing dexamethasone. At 45 days after the initiation of treatment, clinical resolution was achieved, with recovery of vision in the left eye. The topical treatment was successful, and the animal returned to normal behavior, locomotion, and feeding patterns.

This research aims to describe the cost-benefit analysis of selective therapy adoption for clinical mastitis based on the identification of pathogens using on-farm culture system. A survey of clinical mastitis cases was carried out in the database of a dairy herd with 500 lactating Holstein cows, during the period of September 2017 to October 2019. Variables such as frequency of cases, main pathogens identified, costs with antibiotic therapies and milk disposal were evaluated and compared between one year before (P1) and after (P2), the farm's selective therapy adoption. During the study period, 599 cases of clinical mastitis were identified, 361 in P1 and 238 in P2. The average cost of therapies was US74.33 and US91.82 for P1 and P2. Considering the two years of the study, the estimated cost of treating clinical mastitis was US45,444.31, of which US$27,559.97 were spent in P1 and US17,884.34 in P2. Based on the result of the identification of the pathogen types associated with clinical mastitis, selective therapy demonstrated cost reduction already in the first year of implementation.

The high lipid content in porcine oocytes impairs in vitro embryo production (IVP). Here, we evaluated the influence of two different lipid modulators during in vitro maturation (IVM) on the embryo development and the lipid content of oocytes and embryos. In Experiment I, oocytes were exposed to 50 μM docosahexaenoic acid (DHA) with (+) or without (−) the presence of porcine follicular fluid (pFF). In Experiment II, phenazine ethosulfate (PES) was added during IVM at two concentrations (0.5 and 0.05 μM). The pFF- with 50 μM DHA treatment impaired nuclear maturation, cleavage and blastocyst rates (p < 0.05). Oocytes in pFF- media accumulated less lipids (p < 0.05). The addition of 0.5 μ M PES reduced all development rates (p < 0.05) and resulted in higher lipid content for oocytes and embryos. Only 0.05 μM PES oocytes matured similarly to the control (p > 0.05), although embryo development and embryo lipid content was similar to 0.5 μM PES oocytes (p > 0.05). Thus, 50 μM DHA supplementation in the IVM medium without pFF impaired oocyte maturation and embryo development rates without interfering in oocyte lipid content even in the presence of pFF. Maturation with PES neither favored porcine embryo development nor reduced their lipid content.

Summary: Bovine sex-sorted sperm have been commercialized and successfully used for the production of transgenic embryos of the desired sex through the sperm-mediated gene transfer (SMGT) technique. However, sex-sorted sperm show a reduced ability to internalize exogenous DNA. The interaction between sperm cells and the exogenous DNA has been reported in other species to be a CD4-like molecule-dependent process. The flow cytometry-based sex-sorting process subjects the spermatozoa to different stresses causing changes in the cell membrane. The aim of this study was to elucidate the relationship between the redistribution of CD4-like molecules and binding of exogenous DNA to sex-sorted bovine sperm. In the first set of experiments, the membrane phospholipid disorder and the redistribution of the CD4 were evaluated. The second set of experiments was conducted to investigate the effect of CD4 redistribution on the mechanism of binding of exogenous DNA to sperm cells and the efficiency of lipofection in sex-sorted bovine sperm. Sex-sorting procedure increased the membrane phospholipid disorder and induced the redistribution of CD4-like molecules. Both X-sorted and Y-sorted sperm had decreased DNA bound to membrane in comparison with the unsorted sperm; however, the binding of the exogenous DNA was significantly increased with the addition of liposomes. Moreover, we demonstrated that the number of sperm-bound exogenous DNA was decreased when these cells were preincubated with anti-bovine CD4 monoclonal antibody, supporting our hypothesis that CD4-like molecules indeed play a crucial role in the process of exogenous DNA/bovine sperm cells interaction.