Thesis (Ph. D.)--Ohio State University, 2007. / Full text release at OhioLINK's ETD Center delayed at author's request

El objetivo de este estudio fue comparar la eficacia de una vacuna subunitaria contra mastitis causada por Escherichia coli con la de una vacuna comercial (Enviracor®; Zoetis Inc), en vacas lecheras confinadas de la zona central, a través del estado de salud mamaria, producción de leche e índices de calidad de la misma. Se incluyeron vacas de forma aleatoria a dos grupos experimentales. Un grupo (n = 230) recibió la vacuna subunitaria, mientras que el otro (n=213) fue vacunado con la vacuna J5. El protocolo de inmunización fue similar para ambos grupos, e incluyó tres dosis de vacuna vía subcutánea; la primera al momento del secado, la segunda al preparto y la tercera alrededor de los 7 días después del parto.

Memoria para optar al Título Profesional de Médico Veterinario / Las células troncales mesenquimáticas (MSC, del inglés Mesenchymal Stem Cells o Mesenchymal Stromal Cells) son células estromales multipotentes que están presentes en todos los tejidos fetales y adultos. Cuentan con propiedades inmunomoduladoras, angiogénicas y antibacterianas que las hacen una potencial herramienta terapéutica para el tratamiento de diversas patologías. Su utilización para el tratamiento de enfermedades que afectan a equinos y caninos ha sido ampliamente reportada, sin embargo, existen escasos estudios sobre su potencial uso terapéutico en la especie bovina. Esto a pesar de que existen numerosas patologías que afectan la eficiencia productiva en esta especie las cuales podrían ser tratadas mediante el uso de MSC, como es el caso de la mastitis. El objetivo del presente estudio fue evaluar la seguridad de una potencial terapia de MSC para el tratamiento de la mastitis, mediante la determinación del efecto de la administración intramamaria de dos dosis de MSC alogénicas derivadas de tejido adiposo fetal bovino, sobre variables fisiológicas incluyendo perfil bioquímico sanguíneo y la expresión de citoquinas proinflamatorias en linfocitos de sangre periférica (PBL) bovinos. Vaquillas Holstein (N=6) clínicamente sanas pertenecientes a una lechería comercial fueron seleccionadas e inoculadas los días 0 y 10 con una suspensión de 2,5 x 107 de MSC suspendidas en 3 mL de Ringer Lactato en dos cuartos mamarios seleccionados al azar. Los dos cuartos mamarios restantes fueron inoculados con 3 mL de Ringer Lactato como control. El efecto de la inoculación de MSC fue evaluado sobre constantes fisiológicas y variables clínicas de la ubre. Cada cinco días se colectaron muestras de sangre para análisis de perfil bioquímico, determinación de fibrinógeno y aislamiento de PBL. La expresión de citoquinas proinflamatorias y quimioquinas asociadas a rechazo inmune IL-2, IFN-ɣ, TNF-ɑ, CCL-2, CCL-5 y CXCL3 fue cuantificada mediante PCR cuantitativo (Q-PCR) en PBL. No se evidenciaron cambios en constantes fisiológicas ni en las variables evaluadas en la glándula mamaria con la excepción de secreción láctea en una de las vaquillas. Los valores de termografía de los cuartos mamarios estuvieron bajo el intervalo referencial esperado y no hubo diferencia (P>0,05) entre los cuartos inoculados con MSC y los inoculados con PBS. Los niveles sanguíneos de variables del perfil bioquímico y de la expresión de mRNA de citoquinas proinflamatorias no fueron distintos (P>0,05) durante los días de estudio. Los análisis realizados indican que la administración 2 intramamaria de dos dosis de MSC en vaquillas Holstein no generó cambios en las variables analizadas. Adicionalmente, los resultados indican que una potencial terapia para la mastitis bovina utilizando MSC podría ser segura, sin embargo, es necesario evaluar su efectividad en vacas con mastitis / Mesenchymal stem cells (MSC) are multipotent stromal cells that are present in all fetal and adult tissues. MSC possess immunomodulatory, angiogenic and antibacterial properties which make them a potential tool for the treatment of diverse pathologies. The use of MSC for the treatment of pathologies affecting equines and canine has been widely reported, however; few studies have described the therapeutic potential of MSC in the bovine specie. There are numerous pathologies that affect the productive efficiency of cattle, such as mastitis, which may be treated with MSC. The aim of the present study, was to evaluate the safety of a potential MSC therapy for the treatment of mastitis by determination of the effect of the intramammary administration of two doses of allogeneic MSCs derived from fetal bovine adipose tissue on physiological variables including clinical features, biochemical profile and the expression of proinflammatory cytokines in bovine peripheral blood lymphocytes (PBL). Clinically healthy Holstein heifers (N=6) from a commercial dairy farm were selected and inoculated on days 0 and 10 with a suspension of 2,5 x 107 MSC suspended in 3 mL of Ringer Lactate in two mammary quarters randomly selected. The remaining two mammary quarters were inoculated with 3 mL of Ringer Lactate as control. The effect of MSC was evaluated on physiological constants and clinical variables of the udder. Blood samples were collected every five days for analysis of biochemical profile, determination of fibrinogen and isolation of PBL. The expression of proinflammatory cytokines and chemokines associated with immune rejection IL-2, IFN-γ, TNF-γ, CCL-2, CCL-5 and CXCL3 was determined by quantitative PCR (Q-PCR) in PBL. There were no changes in physiological constants or in the udder with the exception of milk secretion in one of the heifers, the thermography values of quarters were below the expected referential interval and there was no difference (P>0.05) between the quarters inoculated with MSC compared to 3 those inoculated with PBS. The levels of the biochemical profile and mRNA of proinflammatory cytokines were not different (P>0.05) during the study. The analyzes indicate that the intramammary administration of two doses of MSC in Holstein heifers did not generate changes in the variables analyzed. Data generated in the present study indicated that a potential therapy for bovine mastitis based on MSC is safe; however, the effectiveness of this therapy require further evaluation in cows with mastitis / FONDEF IDeA ID15I10129

The objectives of this study were (1) to evaluate the use of digital infrared thermal imaging as a diagnostic tool for early detection of mastitis, (2) to test the usefulness of thermography in the quantative evaluation of mammary function in high and low milk producing cows and (3) to establish base-line measurements of thermographic patterns of the bovine claw. To investigate these objectives, three experiments were conducted to determine the link between thermal temperature gradients of the bovine mammary gland to level of milk production (high milk producers vs. low milk producers), early diagnosis of mastitis and lameness evaluation in dairy cattle. The first study investigated the relationship between level of milk production to udder conformation and thermal signatures of the udder gradients. The second study (case study) involved the use of DITI for diagnosis of mastitis in dairy cows under a heatstressed environment. Lastly, the third study was to establish base-line measurements in temperature gradients of regions of the bovine claw.

Bovine mastitis is a significant disease affecting the dairy industry worldwide. The most frequently causative agent of contagious bovine mastitis is Staphylococcus aureus that produces numerous virulence factors contributing to its pathogenesis. However, it is not clearly defined which virulence factors play a critical role in bovine mastitis due to the heterogeneous virulence factor profiles in S. aureus isolated from different hosts and disease types. Among many virulence factors, it has long been postulated that staphylococcal cytotoxins and superantigens (SAgs) play an important role in the pathogenesis of S. aureus in bovine mastitis due to their potent toxicity toward host immune response. However, it has been a great challenge to determine the definite role of staphylococcal cytotoxins and SAgs in S. aureus pathogenesis due to the presence of multiple redundant cytotoxins and SAgs in a single S. aureus strain. Our longterm goal is to develop an effective vaccine to protect dairy cattle from S. aureus infection. The objective of this study is to; 1) determine the role of staphylococcal cytotoxins and superantigens in bovine mastitis; 2) develop a inducible and secretory expression vector and host system for a high production yield of recombinant protein; and 3) evaluate the protective effect of recombinant protein vaccine composed of staphylococcal cytotoxins and SAgs. The rationale of the proposed research is that development of an effective vaccine against S. aureus will prevent significant economic loss in the dairy industry and reduce the use of antibiotics in the dairy industry to prevent emergence of antibiotic resistance pathogens

Animal activity, in combination with physiological factors, can be used for early disease detection in dairy cattle. An initial study determined the impact of flunixin meglumine (FM), a non-steroidal anti-inflammatory drug, on activity measures, dry matter intake (DMI) and milk production during experimentally induced Escherichia coli mastitis. A total of 24 primiparous and multiparous lactating dairy cows were challenged with E.coli 727 in one quarter. Of the 24 E.coli challenged animals, 12 were administered FM at 0.002 µg/45.5kg of body weight at the onset of clinical mastitis signs. The remaining 12 cows were untreated. An additional 11 cows were infused with 1 mL of sterile phosphate-buffered saline, and served as the control group. Activity measures were collected through the use of the Afi PedometerPlus© and HOBO® data loggers. E.coli mastitis altered animal activity and improvement in DMI and milk production of animals given FM was observed, thus providing evidence for the use of an NSAID as supportive therapy for mastitis. Additionally, activity and blood metabolites concentrations were collected and analyzed from periparturient dairy cows at the Virginia Tech Dairy Center to determine the likelihood of disease occurrence. Primiparous and multiparous Holstein, Jersey, and Crossbred dairy cows were monitored for daily rest bouts, rest duration, and rest time throughout the pre and postpartum periods. Activity measurements were collected using Afi PedometerPlus© pedometers. It was concluded that evaluation of activity changes, and comparison of deviations from healthy herdmates, could allow producers to utilize activity monitoring to proactively manage dairy herd health. / Master of Science

no abstract provided by author / Master of Science

Intramammary infections (IMI) are common in non-lactating heifer and dry cow mammary glands and occur during periods of appreciable mammary growth and development. The presence of these infections is expected to negatively impact mammary growth and development but has yet to be investigated. The works reported here investigated how IMI affects mammary tissue structure, cellularity, and the expression of integral mammogenic hormone receptors implicated in mammary growth. Non-pregnant non-lactating cows (n = 19) were administered estradiol and progesterone to stimulate mammary growth and 2 quarters of each cow were subsequently infused with either saline (n = 19) or Staphylococcus aureus (n = 19). Intramammary infusion of Staphylococcus aureus increased the number of immune cells present in gland secretions and also increased the proportion of neutrophils comprising these secretion somatic cells. Mammary tissues from quarters infused with Staphylococcus aureus contained more immune cells, less mammary epithelial tissue area, and greater tissue areas of intralobular stromal tissue than saline quarters. Staphylococcus aureus quarters also contained more apoptotic mammary epithelial cells and a lower proportion of apoptotic cells in the intralobular stroma compartment than saline infused quarters; this signified that Staphylococcus aureus quarters had less epithelial growth and experienced an expansion and/or lack of regression of stromal tissues. The number of cells expressing estrogen receptor α (ESR1) and progesterone receptor (PGR), as well as staining characteristics of ESR1 and PGR positive nuclei was also examined in these tissues. No appreciable differences were observed in any of the examined ESR1 and PGR measures between Staphylococcus aureus and saline mammary glands, but myoepithelial cells from Staphylococcus aureus glands had a greater nuclear staining area than saline quarters, indicating that these cells were affected by IMI. The results of these investigations indicate that IMI, in mammary glands that are concurrently stimulated to grow and develop, limits the growth of mammary epithelium and impairs regression of the stromal tissue, both of which are necessary for successful lactational performance. / PHD / Successful growth and development of the dairy cow udder (mammary gland) is important and has long-term impacts on milk production. Most mammary growth occurs during the first pregnancy but, at this same time, a bacterial infection can be present within the mammary gland and is expected to hinder normal growth and development. The studies conducted here sought to examine how a bacterial infection, within a cow’s udder, affects mammary gland growth and development. Overall, it was observed that a bacterial infection in the mammary gland reduced the amount of functional tissue that would eventually produce milk while simultaneously increasing the amount of connective tissue. Infected mammary glands also had a greater number of dying mammary cells, reducing the number of cells that would eventually produce milk. Estrogen and progesterone are known to be integral in supporting mammary growth, so an examination of the number of cells being able to receive signals from estrogen and progesterone was also undertaken; presence of an infection did not alter the number of cells able to receive estrogen and progesterone’s signal. This work furthered our understanding of how bacterial infections affect mammary tissue and alter normal developmental processes.

No description available.

No description available.