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Controlling mastitis in dairy herds relies on good prevention and detection methods. This dissertation describes two areas of research relating to mastitis control. In the first objective, the efficacy of 2 vaccines against Escherichia coli mastitis in mid-lactation dairy cows was evaluated. Secondly, in a series of 3 studies, milk and activity sensor data were used to derive models for clinical mastitis (CM) detection, and models were tested for their ability to indicate the causative pathogen type. Primiparous and multiparous animals were vaccinated with 1 of 2 commercially available J5 vaccines (V1 or V2) or served as unvaccinated controls (CTL). Intramammary challenge with E. coli approximately 84 d later resulted in few treatment differences in the clinical and behavioral responses, except that vaccinated cows exhibited fever (≥ 39.4 °C) 3 h earlier and laid down for longer periods than CTL. Although vaccinated cows had similar severity and duration of CM, V1 cows produced more serum IgG1 and IgG2 than V2 cows. Our results indicated that the effects of vaccination were diminished in mid-lactation, and that antibodies are not the limiting factor in defending against induced E. coli mastitis. Multiple regression models, incorporating the slope changes in relevant milk and activity sensor data, were developed to indicate all CM cases (ACM), or specifically, CM due to Gram-negative (GN) or Gram-positive (GP) bacteria. Gram-specific models had greater detection accuracy (> 80%) than the ACM model (75%) when evaluated using the model training dataset, but independent evaluation demonstrated reduced sensitivity (Se) of detecting CM by all models (GN, 62%, ACM, 56%, and GP, 32% Se). Data in the 3 d prior to CM were more important in detecting GN pathogens, whereas the best GP models incorporated changes more than 1 week prior to CM detection. Still, model performance was imperfect. Next, models were rederived from a dataset that better reflected the infection distribution of the herds its use was intended for. However, the Se of detecting CM in real-time, across 2 farms, was < 21% for all models, and categorization by Gram-status had no benefit. An insufficient number of CM cases was considered to contribute to the poor detection performance of models and limited repeatability across farms. Consequently, models derived in this study were inadequate for implementation as mastitis detection tools. In the future, development of new sensors and application of more sophisticated algorithms to the field of mastitis detection may improve the accuracy of models using sensor data. / Doctor of Philosophy / Mastitis is an important disease of dairy cattle that adversely affects animal welfare, productivity, and milk quality. Controlling mastitis in dairy herds relies on good prevention and detection methods. In this dissertation, we investigated two elements of mastitis control: 1) the effects of vaccination in protecting against mastitis, and 2) the ability of on-farm sensor data to detect clinical mastitis (CM) and indicate the causative pathogen type. Coliform bacteria commonly cause CM, and vaccination against these bacteria can reduce the severity of the disease. We evaluated the effect of 2 different vaccines on the clinical, behavioral, and immune response in cows with experimental mastitis caused by Escherichia coli. Our findings indicated that the effects of vaccination had diminished at the time of experimental mastitis, as vaccinated cows had no improvement in clinical recovery compared with unvaccinated controls. Although no clinical or behavioral differences were observed between the 2 different vaccines, the antibody response differed, suggesting that antibodies are not the key player underpinning the mechanisms of vaccination against induced coliform mastitis in mid-lactation. Rapid detection and diagnosis of mastitis is important to reduce effects on the cow, and to support decision making for the appropriate intervention. We aimed to develop and test mastitis detection models that utilized data collected by on-farm sensor technologies. Milk and activity parameters, which may be differentially affected by mastitis depending on the pathogen causing infection, were used in multiple regression models for detecting any CM case, or specifically CM caused by Gram-positive or Gram-negative bacteria. Gram-specific models were initially estimated to have > 80% accuracy in classifying cows with and without mastitis, but further validation demonstrated that the models were not repeatable when tested independently. Subsequently, models that were more suited to the farms they were to be implemented on were developed, and tested, revealing limited performance in detecting any case of CM, or CM due to the Gram-specific pathogens. Model derivation was limited by an insufficient number of CM cases to represent the variation in different cases of CM within the Gram-positive and Gram-positive classifications. Although our models did not show promise as a mastitis detection tool, milk and activity data may be incorporated with other sensor data for improved detection and diagnosis of mastitis.

INTRODUCTION: Idiopathic granulomatous mastitis (IGM) is becoming more commonly recognized and reported more often. Currently, many recommend corticosteroids in its management. PRESENTATION OF CASE: A 34-year-old G3P2 Hispanic female, 28 weeks pregnant, presented with a 19 cm right breast mass. She had a known prolactinoma treated with bromocriptine which was discontinued during her pregnancy. Ultrasound guided core biopsy procedure revealed granulomatous mastitis. The patient was told that the mass would resolve with observation. The patient seen at another institution by an infectious disease specialist who started treatment with amphotericin for presumptive disseminated coccidioidomycosis. Repeated titers were negative for coccidioides antibody. Repeat cultures were negative as well. Due to the persistence of the infectious disease specialist, tissue cultures were performed on fresh tissue specimens, which did not grow bacterial, fungal, nor acid fast organisms. The amphotericin regimen resulted in no improvement of her breast mass after 10 weeks. Within two weeks of stopping the antifungal therapy, however, the mass diminished to 6 cm. The patient delivered at 39 weeks. Bromocriptine was restarted, and within 4 weeks, the lesion was no longer palpable. She had not shown signs of recurrence for 32 months. DISCUSSION: Treatment recommendations for IGM vary widely but antibiotics and antifungal medications are not recommended. Corticosteroid treatment is most commonly recommended, however, outcomes may not be different from management with observation. Prolactin may be involved in the pathophysiology of the process. CONCLUSION: IGM is becoming recognized more frequently. Observation and patience with natural history can be an effective management. (C) 2015 The Authors. Published by Elsevier Ltd. on behalf of Surgical Associates Ltd.

Clinical cases of bovine mastitis are most severe in the early stages of lactation. The causes of this increased propensity for severe mastitis during early lactation, compared to mid and late lactation are unclear. In order to better understand the early lactation immune response to mastitis, a murine model of mastitis was employed. Intramammary inoculation of a mastitis causing Escherichia coli strain was performed in lactating mice at various stages of lactation to model the immune response seen in cows during lactation. In our experiments, mice in the early stages of lactation exhibited altered mRNA expression of cytokines IL-1β, IL-6, IL-10, and TNFα over the course of infection when compared to mice at mid lactation. Additionally, increased bacterial growth was observed in the mammary gland of mice infected during early lactation compared to late lactation. These results are consistent with the immune response observed in cows at early lactation. These results suggest that the mouse may provide a useful model to study differences in the immune response seen during different times in lactation.

Mastitis is a syndrome manifested by mammary gland inflammation which is thought to cause between $300 and $400 million in annual losses to the Canadian Dairy Industry. Studies have indicated that <i>S. aureus</i> may cause the production of anti-inflammatory cytokines which may enhance its survival within the bovine mammary gland. However, other studies have reported differing results following S. aureus intramammary infection (IMI). This thesis tested the hypothesis that S. aureus generated anti-inflammatory cytokine responses at the site of infection. In the first objective, different S. aureus isolates were screened for their effects on cytokine production (IFN-γ, TNF-α, IL-4 and IL-10) by bovine peripheral blood mononuclear cells (PBMCs) in vitro. Nine S. aureus isolates were co-cultured with PBMCs from lactating dairy cattle. Cattle used in the study had recall immune responses to <i>S. aureus</i>. The majority (6/9) of S. aureus isolates had minor effectors on cytokine production. The three remaining isolates generated large cytokine responses with both pro-inflammatory (IFN-γ and TNF-α) and anti-inflammatory (IL-4 and IL-10) characteristics. Two of these three isolates were tested in vivo by experimentally infecting lactating ewes. Cytokine production was characterized in the teat end, the mammary parenchyma and the supramammary lymph nodes (SMLNs). One isolate generated anti-inflammatory responses <i>in vivo</i> (IL-4 and IL-10) whilst the other generated both pro-inflammatory (IFN-γ) and anti-inflammatory (IL-10) responses in vivo. Given that some studies have suggested a role of staphylococcal enterotoxin C (sec) in the generation of anti-inflammatory responses, the role of sec was also investigated using bovine PBMCs. When purified SEC protein was co-cultured with PBMCs from beef steers, anti-inflammatory cytokines were produced. However, a <i>S. aureus</i> strain which was transformed for the sec gene did not affect cytokine production when co-cultured with PBMCs from lactating dairy cattle. The results of this thesis suggest that <i>S. aureus</i> infection can cause anti-inflammatory cytokine production but the response depends on the isolate causing the infection. Furthermore, the role of sec appears to be minimal.

Mastitis is a syndrome manifested by mammary gland inflammation which is thought to cause between $300 and $400 million in annual losses to the Canadian Dairy Industry. Studies have indicated that <i>S. aureus</i> may cause the production of anti-inflammatory cytokines which may enhance its survival within the bovine mammary gland. However, other studies have reported differing results following S. aureus intramammary infection (IMI). This thesis tested the hypothesis that S. aureus generated anti-inflammatory cytokine responses at the site of infection. In the first objective, different S. aureus isolates were screened for their effects on cytokine production (IFN-γ, TNF-α, IL-4 and IL-10) by bovine peripheral blood mononuclear cells (PBMCs) in vitro. Nine S. aureus isolates were co-cultured with PBMCs from lactating dairy cattle. Cattle used in the study had recall immune responses to <i>S. aureus</i>. The majority (6/9) of S. aureus isolates had minor effectors on cytokine production. The three remaining isolates generated large cytokine responses with both pro-inflammatory (IFN-γ and TNF-α) and anti-inflammatory (IL-4 and IL-10) characteristics. Two of these three isolates were tested in vivo by experimentally infecting lactating ewes. Cytokine production was characterized in the teat end, the mammary parenchyma and the supramammary lymph nodes (SMLNs). One isolate generated anti-inflammatory responses <i>in vivo</i> (IL-4 and IL-10) whilst the other generated both pro-inflammatory (IFN-γ) and anti-inflammatory (IL-10) responses in vivo. Given that some studies have suggested a role of staphylococcal enterotoxin C (sec) in the generation of anti-inflammatory responses, the role of sec was also investigated using bovine PBMCs. When purified SEC protein was co-cultured with PBMCs from beef steers, anti-inflammatory cytokines were produced. However, a <i>S. aureus</i> strain which was transformed for the sec gene did not affect cytokine production when co-cultured with PBMCs from lactating dairy cattle. The results of this thesis suggest that <i>S. aureus</i> infection can cause anti-inflammatory cytokine production but the response depends on the isolate causing the infection. Furthermore, the role of sec appears to be minimal.

No description available.

This thesis is an investigation of the objective assessment of pain through the use of pressure algometers and rumination tags and the effects of pain management therapy for experimentally-induced mastitis on behaviour and physiological measures in dairy cattle. Twenty-four lactating Holstein cows were enrolled in a lipopolysaccharide (LPS) endotoxin challenge study, where one mammary quarter was infused with 25 µg of Escherichia coli (E. coli) LPS endotoxin. Subsequently, a subcutaneous injection of either a non-steroidal anti-inflammatory drug (NSAID) (meloxicam; n=12) or placebo (n=12) was randomly allocated and administered using double-blind methods. Several behavioural, physiological and performance parameters were monitored throughout the study period. Beneficial effects of meloxicam administration on pain sensitivity, edema scores and dry matter intake were shown. For a subset of animals receiving placebo treatment, the algometer and rumination tags accurately detected changes in both pain sensitivity and rumination time after endotoxin challenge. / Canadian Bovine Mastitis Research Network and Boehringer-Ingelheim, Canada

Darbo tikslas buvo nustatyti mastito sukėlėjų paplitimą Lietuvos pieninių galvijų populiacijoje. Įvertinti mastito sukėlėjų paplitimą Lietuvoje veisiamų pieninių galvijų bandose. Ištirti metų laiko įtaką mastitų sukėlėjų pasireiškimui karvių piene. Įvertinti mastitų sukėlėjų paplitimą karvių tešmens ketvirčiuose. Ištirti metų sezono ir mastito sukėlėjų įtaką somatinių ląstelių skaičiui pieno mėginiuose. / The objective of this study was to estimate mastitis pathogens prelavence in Lithuanian dairy cattle population. Evaluate the prevalence of mastitis pathogens in dairy cattle herds in Lithuania. Investigate influence of the season to mastitis pathogens manifestation in cow‘s milk. Evaluate the prevalence of mastitis pathogens in udder quarters. Investigate effect of the season and mastitis pathogens on somatic cell count in milk samples.

No description available.