George Barrington - Academia.edu (original) (raw)

Papers by George Barrington

Journal of Veterinary Internal Medicine, Nov 1, 2000

Passive transfer of colostral immunoglobulins has long been accepted as imperative to optimal cal... more Passive transfer of colostral immunoglobulins has long been accepted as imperative to optimal calf health. Many factors, including timing of colostrum ingestion, the method and volume of colostrum administration, the immunoglobulin concentration of the colostrum ingested, and the age of the dam have been implicated in affecting the optimization of absorption. The practice of colostrum pooling, the breed and presence of the dam, and the presence of respiratory acidosis in the calf also may affect passive transfer. Various tests have been reported to accurately measure passive transfer status in neonatal calves. The radial immunodif‐fusion and the enzyme‐linked immunosorbent assay (ELISA) are the only tests that directly measure serum IgG concentration. All other available tests including serum total solids by refractometry, sodium sulfite turbidity test, zinc sulfate turbidity test, serum γ‐glutamyl transferase activity, and whole blood glutaraldehyde gelation estimate serum IgG concentration based on concentration of total globulins or other proteins whose passive transfer is statistically associated with that of IgG. This paper presents a comprehensive review of the literature of passive transfer in calves including factors that affect passive transfer status, testing modalities, effects of failure of passive transfer on baseline mortality, consequences of failure of passive transfer, and some treatment options. Many previously accepted truisms regarding passive transfer in calves should be rejected based on the results of recent research.

Javma-journal of The American Veterinary Medical Association, Jul 15, 2006

Veterinary Immunology and Immunopathology, Jun 1, 2011

Mycobacterium avium subsp. paratuberculosis (Map), the etiologic agent of Johne's disease (JD) in... more Mycobacterium avium subsp. paratuberculosis (Map), the etiologic agent of Johne's disease (JD) in ruminants, has been implicated in the pathogenesis of Crohn's disease (CD) in humans. We developed a bovine ileal cannulation model to facilitate comparison of the immune response to Map and the mechanisms of pathogenesis in cattle and humans. Initial studies showed a T cannula could be maintained for up to a year in calves without inducing inflammation or adversely affecting intestinal function. Map introduced through the cannula established a persistent low level of infection without inflammation. Infection elicited an immune response to Map antigens detectable by flow cytometry. Further studies now show the cannulation model can be used with cows during the later stage of infection, affording access to the target tissue at all stages of infection. The studies also revealed no difference in infectivity or immunogenicity of isolates of Map obtained from cattle or humans with CD. Comparison of the immune response to Map during the early and late stages of infection using PCR, flow cytometry and QRT-PCR, showed the immune response early in the disease process is dominated by CD4 T cells. A CD8 response is

Parasite Immunology, Sep 1, 2001

Young calves possess a strong innate immunity against Babesia bovis infection that lasts for appr... more Young calves possess a strong innate immunity against Babesia bovis infection that lasts for approximately 6 months after birth and is abrogated with the removal of the spleen. This immunity is characterized as cellular involving a soluble mediator. Nitric oxide has been implicated by virtue of its babesiacidal affects in vitro, but questioned to be as effective in vivo, due to its ability to downregulate type‐1 immunity. Spleen cells were obtained from 4‐month‐old calves and adult steers and processed for monitoring cytokine and inducible nitric oxide synthase (iNOS) mRNA expression during the response to initial B. bovis infection. The data provided evidence of a transient role for nitric oxide in innate immunity, characterized by brief iNOS induction in the spleen of calves that was not detectable in the spleens of adults. The iNOS message followed the early induction of interleukin (IL)‐12 and interferon (IFN)‐γ message in calves. The induction of IL‐12 and IFN‐γ message in adults was delayed until IL‐10 message was induced. Transformation growth factor‐β mRNA expression levels were greater in spleen cells from adults early in infection and then declined, whereas expression levels increased in spleen cells from calves later in the infection process. Together, the data support the concept of ‘first come, first serve’ cytokine influence over cellular activities, the importance of a type‐1 response in the control of an initial infection and the need for tight regulation in order to prevent pathology associated with over production of nitric oxide and inflammatory cytokines.

Schalm's Veterinary Hematology, Mar 4, 2022

Journal of Zoo and Wildlife Medicine, Mar 1, 2013

A 5-yr-old, intact male Suri alpaca (Vicugna pacos) presented with acute onset of anorexia, depre... more A 5-yr-old, intact male Suri alpaca (Vicugna pacos) presented with acute onset of anorexia, depression, and reluctance to stand. Exploratory laparotomy revealed diffuse peritonitis resulting from penetration of a 5-cm wire through the second gastric compartment (C2). Due to the severity of the alpaca's condition and its deteriorating nature, euthanasia at the time of surgery was elected. This is the first published case of a condition commonly observed in cattle (traumatic gastroperitonitis, ''Hardware disease'') to be reported in an alpaca.

Veterinary Radiology & Ultrasound, Mar 1, 1996

Radiographic examination proved incapable of determining the extent and severity of chronic sinus... more Radiographic examination proved incapable of determining the extent and severity of chronic sinusitis in a goat. Computed tomography was subsequently used to clearly define the nature and extent of the lesion.

PubMed, Aug 15, 1995

An 18-month-old sexually intact male llama and a 7-month-old female llama were examined because o... more An 18-month-old sexually intact male llama and a 7-month-old female llama were examined because of weakness, lethargy, and recumbency. Both had signs of ascending motor paralysis with minimal or no afferent sensory loss. Tick paralysis was diagnosed on the basis of complete clinical recovery following removal of a single, attached and engorged female tick (Dermacentor andersoni) from each llama. The male llama recovered within a few hours after removal of the tick, but recovery in the female llama required several days. Serum creatine kinase activity was high in both llamas, possibly as a result of direct effects of toxin on muscles or nerves.

PubMed, Sep 1, 2007

A 12-year-old, castrated male llama (Lama glama) presented with a 12-cm diameter cranial mass. Co... more A 12-year-old, castrated male llama (Lama glama) presented with a 12-cm diameter cranial mass. Computed tomography and postmortem examination revealed that the mass invaded the calvarium and compressed the rostral part of the brain. Light microscopic examination confirmed a fungal granuloma.

PubMed, Oct 1, 2013

Computed tomography was used to aid in the antemortem diagnosis of leukoencephalomyelitis in a go... more Computed tomography was used to aid in the antemortem diagnosis of leukoencephalomyelitis in a goat infected by caprine arthritis encephalitis virus (CAEV). Imaging results were corroborated by histologic examination. This report discusses various methods of imaging the nervous system and their potential for use in the antemortem diagnosis of CAEV neurologic changes.

PubMed, Sep 1, 2000

An adult, intact male alpaca was presented with an acute onset of unilateral scrotal swelling. Fo... more An adult, intact male alpaca was presented with an acute onset of unilateral scrotal swelling. Following complete physical and ultrasonographic examination, the most likely differential diagnoses were orchitis, hematoma, and testicular torsion. The animal was castrated and histopathologic evaluation revealed unilateral orchitis. Streptococcus equi subsp. zooepidemicus was cultured.

PubMed, Mar 1, 2001

An 8-year-old, female llama was evaluated for nonhealing, ulcerative, cutaneous lesions, which al... more An 8-year-old, female llama was evaluated for nonhealing, ulcerative, cutaneous lesions, which also involved the mammary gland. Biopsies of the lesions distant from and within the mammary gland area revealed an aggressive carcinoma. The tumor was confirmed at necropsy to be a mammary gland adenocarcinoma with cutaneous metastasis.

PubMed, Feb 15, 1993

Rupture of the urinary bladder of a cow occurred secondary to prolonged dystocia. Primary surgica... more Rupture of the urinary bladder of a cow occurred secondary to prolonged dystocia. Primary surgical closure of the tear was performed after drainage of the uroperitoneum, and the cow recovered without complications.

Veterinary Immunology and Immunopathology, Oct 1, 2012

A calf model was used to determine if the depletion of CD4 T cells prior to inoculation of Mycoba... more A calf model was used to determine if the depletion of CD4 T cells prior to inoculation of Mycobacterium avium subsp. paratuberculosis (Map) would delay development of an immune response to Map and accelerate disease progression. Ileal cannulas were surgically implanted in 5 bull calves at 2 months of age. Two calves were depleted of CD4 T cells by intravenous injection of anti-bovine CD4 antibody administered 24 h prior to inoculation with Map. The two CD4-depleted calves and one non-depleted calf were inoculated via ileal cannula with 1 × 10 8 cfu live Map every 3 days for a total of 4 inoculations. Two additional calves served as non-depleted and uninfected controls. Injection with the anti-CD4 mAb reduced the frequency of CD4 T cells from a pre-depletion average of 15% to less than 1% in PBMC at 24 h. However, a consistent proliferative response dominated by CD4 T cells, developed in both treated and untreated calves over the course of the 6-month study period. Recovery of Map from serial biopsies obtained from the CD4-depleted and non-depleted calves after Map infection did not differ. In addition, CD4 depletion did not increase the level of Map shed in the feces over the non-depleted animal.

PubMed, Jul 15, 1991

Listeria monocytogenes was found to be the cause of fatal suppurative meningoencephalomyelitis in... more Listeria monocytogenes was found to be the cause of fatal suppurative meningoencephalomyelitis in a 3.5-month-old cria. The cria initially had clinical signs of unilateral peripheral vestibular disease, but on the following day, the cria developed progressive signs of encephalitis. Treatment with antibiotics, flunixin meglumine, and anticonvulsant drugs failed to stop progression of the disease, and the cria was euthanatized. Post-mortem examination revealed otitis media-interna and diffuse suppurative meningoencephalomyelitis. Listeria monocytogenes was isolated from CSF and brain tissue.

PubMed, Oct 1, 1997

A nonhealing wound associated with a laceration in a 12-year-old llama was evaluated. Initial att... more A nonhealing wound associated with a laceration in a 12-year-old llama was evaluated. Initial attempts at closure were unsuccessful and biopsy revealed scar tissue. Subsequent biopsies, 18 mo later, revealed squamous cell carcinoma with regional metastasis. This report describes squamous cell carcinoma, secondary to a traumatic wound in a llama.

Journal of Dairy Science, 1997

Explants of mammary tissue from cows in late pregnancy were incubated for 72 h in serum-free, hor... more Explants of mammary tissue from cows in late pregnancy were incubated for 72 h in serum-free, hormonally defined media to investigate the regulation of the bovine mammary IgG1 receptor. Treatments included incubation in basal medium alone, basal medium plus estradiol-17 beta, basal medium plus prolactin, or basal medium plus estradiol-17 beta and prolactin. alpha-Lactalbumin production was measured by radioimmunoassay in culture supernatants collected at 24, 48, and 72 h. Explants were examined immunohistochemically for expression of the IgG1 receptor at 24, 48, and 72 h. alpha-Lactalbumin concentrations increased, and IgG1 receptor expression decreased, by 72 h with explants cultured in the medium containing prolactin. Results suggest that, in addition to its positive lactogenic effect, prolactin decreases expression of the bovine mammary IgG1 receptor.

PLOS ONE, Apr 21, 2014

Background: Mortality from epizootic pneumonia is hindering re-establishment of bighorn sheep pop... more Background: Mortality from epizootic pneumonia is hindering re-establishment of bighorn sheep populations in western North America. Mycoplasma ovipneumoniae, a primary agent of this disease, is frequently carried asymptomatically by the domestic sheep and goats that constitute the reservoir of this agent for transmission to bighorn sheep. Our long-term objective is to reduce the risk of M. ovipneumoniae infection of bighorn sheep; one approach to this objective is to control the pathogen in its reservoir hosts. Methods: The safety and immunogenicity of M. ovipneumoniae for domestic sheep was evaluated in three experimental immunization protocols: 1) live M. ovipneumoniae (50 ug protein); 2) killed M. ovipneumoniae (50 ug whole cell protein) in oil adjuvant; and 3) killed M. ovipneumoniae (250 ug whole cell protein) in oil adjuvant. Immunogenicity was assessed by two serum antibody measures: competitive enzyme-linked immunosorbent assay (cELISA) (experiments 1-3) and serum growth inhibition (Experiment 3). Passive immunogenicity was also assessed in the third experiment using the same assays applied to blood samples obtained from the lambs of immunized ewes. Results and Conclusions: Adverse reactions to immunization were generally minor, but local reactions were regularly observed at immunization sites with bacterins in oil adjuvants. No evidence of M. ovipneumoniae specific antibody responses were observed in the first or second experiments and no resistance to colonization was observed in the first experiment. However, the ewes in the third experiment developed strong cELISA serum antibody responses and significant serum M. ovipneumoniae inhibition activity, and these responses were passively transferred to their lambs. The results of these trials indicate that immunization with relatively large antigenic mass combined with an adjuvant is capable of inducing strong active antibody responses in ewes and passively immunizing lambs.

Journal of Dairy Science, 1997

The objective of this study was to identify and evaluate expression of IgG 1 receptors by differe... more The objective of this study was to identify and evaluate expression of IgG 1 receptors by different cell types in mammary tissue sections and digestdispersed cells from the bovine mammary gland. An immunohistochemical system utilizing avidin-biotinperoxidase complex demonstrated epithelial expression of IgG 1 receptors in mammary tissue sections from cows producing colostrum but not from cows in lactation. Fluorescence flow cytometry demonstrated that cells dispersed in digests from both tissues producing colostrum and lactating tissues selectively bound IgG 1. Fluorescence flow cytometry, using monoclonal antibodies to cell surface molecules, cytokeratin, and IgG 1 , revealed that leukocytes constituted the largest percentage of cells and were the predominant cell type binding IgG 1 in mammary tissue digests. Although IgG 1 binding to epithelial cells predominated in the gland during colostrum production in situ, digestion and filtration to produce single cell suspensions resulted in the loss of large numbers of epithelial cells. Studies of Ig binding of cells produced by enzymatic digestion must account for the types of cells surviving the digestion process.

Journal of Veterinary Internal Medicine, Nov 1, 2000

Passive transfer of colostral immunoglobulins has long been accepted as imperative to optimal cal... more Passive transfer of colostral immunoglobulins has long been accepted as imperative to optimal calf health. Many factors, including timing of colostrum ingestion, the method and volume of colostrum administration, the immunoglobulin concentration of the colostrum ingested, and the age of the dam have been implicated in affecting the optimization of absorption. The practice of colostrum pooling, the breed and presence of the dam, and the presence of respiratory acidosis in the calf also may affect passive transfer. Various tests have been reported to accurately measure passive transfer status in neonatal calves. The radial immunodif‐fusion and the enzyme‐linked immunosorbent assay (ELISA) are the only tests that directly measure serum IgG concentration. All other available tests including serum total solids by refractometry, sodium sulfite turbidity test, zinc sulfate turbidity test, serum γ‐glutamyl transferase activity, and whole blood glutaraldehyde gelation estimate serum IgG concentration based on concentration of total globulins or other proteins whose passive transfer is statistically associated with that of IgG. This paper presents a comprehensive review of the literature of passive transfer in calves including factors that affect passive transfer status, testing modalities, effects of failure of passive transfer on baseline mortality, consequences of failure of passive transfer, and some treatment options. Many previously accepted truisms regarding passive transfer in calves should be rejected based on the results of recent research.

Javma-journal of The American Veterinary Medical Association, Jul 15, 2006

Veterinary Immunology and Immunopathology, Jun 1, 2011

Mycobacterium avium subsp. paratuberculosis (Map), the etiologic agent of Johne's disease (JD) in... more Mycobacterium avium subsp. paratuberculosis (Map), the etiologic agent of Johne's disease (JD) in ruminants, has been implicated in the pathogenesis of Crohn's disease (CD) in humans. We developed a bovine ileal cannulation model to facilitate comparison of the immune response to Map and the mechanisms of pathogenesis in cattle and humans. Initial studies showed a T cannula could be maintained for up to a year in calves without inducing inflammation or adversely affecting intestinal function. Map introduced through the cannula established a persistent low level of infection without inflammation. Infection elicited an immune response to Map antigens detectable by flow cytometry. Further studies now show the cannulation model can be used with cows during the later stage of infection, affording access to the target tissue at all stages of infection. The studies also revealed no difference in infectivity or immunogenicity of isolates of Map obtained from cattle or humans with CD. Comparison of the immune response to Map during the early and late stages of infection using PCR, flow cytometry and QRT-PCR, showed the immune response early in the disease process is dominated by CD4 T cells. A CD8 response is

Parasite Immunology, Sep 1, 2001

Young calves possess a strong innate immunity against Babesia bovis infection that lasts for appr... more Young calves possess a strong innate immunity against Babesia bovis infection that lasts for approximately 6 months after birth and is abrogated with the removal of the spleen. This immunity is characterized as cellular involving a soluble mediator. Nitric oxide has been implicated by virtue of its babesiacidal affects in vitro, but questioned to be as effective in vivo, due to its ability to downregulate type‐1 immunity. Spleen cells were obtained from 4‐month‐old calves and adult steers and processed for monitoring cytokine and inducible nitric oxide synthase (iNOS) mRNA expression during the response to initial B. bovis infection. The data provided evidence of a transient role for nitric oxide in innate immunity, characterized by brief iNOS induction in the spleen of calves that was not detectable in the spleens of adults. The iNOS message followed the early induction of interleukin (IL)‐12 and interferon (IFN)‐γ message in calves. The induction of IL‐12 and IFN‐γ message in adults was delayed until IL‐10 message was induced. Transformation growth factor‐β mRNA expression levels were greater in spleen cells from adults early in infection and then declined, whereas expression levels increased in spleen cells from calves later in the infection process. Together, the data support the concept of ‘first come, first serve’ cytokine influence over cellular activities, the importance of a type‐1 response in the control of an initial infection and the need for tight regulation in order to prevent pathology associated with over production of nitric oxide and inflammatory cytokines.

Schalm's Veterinary Hematology, Mar 4, 2022

Journal of Zoo and Wildlife Medicine, Mar 1, 2013

A 5-yr-old, intact male Suri alpaca (Vicugna pacos) presented with acute onset of anorexia, depre... more A 5-yr-old, intact male Suri alpaca (Vicugna pacos) presented with acute onset of anorexia, depression, and reluctance to stand. Exploratory laparotomy revealed diffuse peritonitis resulting from penetration of a 5-cm wire through the second gastric compartment (C2). Due to the severity of the alpaca's condition and its deteriorating nature, euthanasia at the time of surgery was elected. This is the first published case of a condition commonly observed in cattle (traumatic gastroperitonitis, ''Hardware disease'') to be reported in an alpaca.

Veterinary Radiology & Ultrasound, Mar 1, 1996

Radiographic examination proved incapable of determining the extent and severity of chronic sinus... more Radiographic examination proved incapable of determining the extent and severity of chronic sinusitis in a goat. Computed tomography was subsequently used to clearly define the nature and extent of the lesion.

PubMed, Aug 15, 1995

An 18-month-old sexually intact male llama and a 7-month-old female llama were examined because o... more An 18-month-old sexually intact male llama and a 7-month-old female llama were examined because of weakness, lethargy, and recumbency. Both had signs of ascending motor paralysis with minimal or no afferent sensory loss. Tick paralysis was diagnosed on the basis of complete clinical recovery following removal of a single, attached and engorged female tick (Dermacentor andersoni) from each llama. The male llama recovered within a few hours after removal of the tick, but recovery in the female llama required several days. Serum creatine kinase activity was high in both llamas, possibly as a result of direct effects of toxin on muscles or nerves.

PubMed, Sep 1, 2007

A 12-year-old, castrated male llama (Lama glama) presented with a 12-cm diameter cranial mass. Co... more A 12-year-old, castrated male llama (Lama glama) presented with a 12-cm diameter cranial mass. Computed tomography and postmortem examination revealed that the mass invaded the calvarium and compressed the rostral part of the brain. Light microscopic examination confirmed a fungal granuloma.

PubMed, Oct 1, 2013

Computed tomography was used to aid in the antemortem diagnosis of leukoencephalomyelitis in a go... more Computed tomography was used to aid in the antemortem diagnosis of leukoencephalomyelitis in a goat infected by caprine arthritis encephalitis virus (CAEV). Imaging results were corroborated by histologic examination. This report discusses various methods of imaging the nervous system and their potential for use in the antemortem diagnosis of CAEV neurologic changes.

PubMed, Sep 1, 2000

An adult, intact male alpaca was presented with an acute onset of unilateral scrotal swelling. Fo... more An adult, intact male alpaca was presented with an acute onset of unilateral scrotal swelling. Following complete physical and ultrasonographic examination, the most likely differential diagnoses were orchitis, hematoma, and testicular torsion. The animal was castrated and histopathologic evaluation revealed unilateral orchitis. Streptococcus equi subsp. zooepidemicus was cultured.

PubMed, Mar 1, 2001

An 8-year-old, female llama was evaluated for nonhealing, ulcerative, cutaneous lesions, which al... more An 8-year-old, female llama was evaluated for nonhealing, ulcerative, cutaneous lesions, which also involved the mammary gland. Biopsies of the lesions distant from and within the mammary gland area revealed an aggressive carcinoma. The tumor was confirmed at necropsy to be a mammary gland adenocarcinoma with cutaneous metastasis.

PubMed, Feb 15, 1993

Rupture of the urinary bladder of a cow occurred secondary to prolonged dystocia. Primary surgica... more Rupture of the urinary bladder of a cow occurred secondary to prolonged dystocia. Primary surgical closure of the tear was performed after drainage of the uroperitoneum, and the cow recovered without complications.

Veterinary Immunology and Immunopathology, Oct 1, 2012

A calf model was used to determine if the depletion of CD4 T cells prior to inoculation of Mycoba... more A calf model was used to determine if the depletion of CD4 T cells prior to inoculation of Mycobacterium avium subsp. paratuberculosis (Map) would delay development of an immune response to Map and accelerate disease progression. Ileal cannulas were surgically implanted in 5 bull calves at 2 months of age. Two calves were depleted of CD4 T cells by intravenous injection of anti-bovine CD4 antibody administered 24 h prior to inoculation with Map. The two CD4-depleted calves and one non-depleted calf were inoculated via ileal cannula with 1 × 10 8 cfu live Map every 3 days for a total of 4 inoculations. Two additional calves served as non-depleted and uninfected controls. Injection with the anti-CD4 mAb reduced the frequency of CD4 T cells from a pre-depletion average of 15% to less than 1% in PBMC at 24 h. However, a consistent proliferative response dominated by CD4 T cells, developed in both treated and untreated calves over the course of the 6-month study period. Recovery of Map from serial biopsies obtained from the CD4-depleted and non-depleted calves after Map infection did not differ. In addition, CD4 depletion did not increase the level of Map shed in the feces over the non-depleted animal.

PubMed, Jul 15, 1991

Listeria monocytogenes was found to be the cause of fatal suppurative meningoencephalomyelitis in... more Listeria monocytogenes was found to be the cause of fatal suppurative meningoencephalomyelitis in a 3.5-month-old cria. The cria initially had clinical signs of unilateral peripheral vestibular disease, but on the following day, the cria developed progressive signs of encephalitis. Treatment with antibiotics, flunixin meglumine, and anticonvulsant drugs failed to stop progression of the disease, and the cria was euthanatized. Post-mortem examination revealed otitis media-interna and diffuse suppurative meningoencephalomyelitis. Listeria monocytogenes was isolated from CSF and brain tissue.

PubMed, Oct 1, 1997

A nonhealing wound associated with a laceration in a 12-year-old llama was evaluated. Initial att... more A nonhealing wound associated with a laceration in a 12-year-old llama was evaluated. Initial attempts at closure were unsuccessful and biopsy revealed scar tissue. Subsequent biopsies, 18 mo later, revealed squamous cell carcinoma with regional metastasis. This report describes squamous cell carcinoma, secondary to a traumatic wound in a llama.

Journal of Dairy Science, 1997

Explants of mammary tissue from cows in late pregnancy were incubated for 72 h in serum-free, hor... more Explants of mammary tissue from cows in late pregnancy were incubated for 72 h in serum-free, hormonally defined media to investigate the regulation of the bovine mammary IgG1 receptor. Treatments included incubation in basal medium alone, basal medium plus estradiol-17 beta, basal medium plus prolactin, or basal medium plus estradiol-17 beta and prolactin. alpha-Lactalbumin production was measured by radioimmunoassay in culture supernatants collected at 24, 48, and 72 h. Explants were examined immunohistochemically for expression of the IgG1 receptor at 24, 48, and 72 h. alpha-Lactalbumin concentrations increased, and IgG1 receptor expression decreased, by 72 h with explants cultured in the medium containing prolactin. Results suggest that, in addition to its positive lactogenic effect, prolactin decreases expression of the bovine mammary IgG1 receptor.

PLOS ONE, Apr 21, 2014

Background: Mortality from epizootic pneumonia is hindering re-establishment of bighorn sheep pop... more Background: Mortality from epizootic pneumonia is hindering re-establishment of bighorn sheep populations in western North America. Mycoplasma ovipneumoniae, a primary agent of this disease, is frequently carried asymptomatically by the domestic sheep and goats that constitute the reservoir of this agent for transmission to bighorn sheep. Our long-term objective is to reduce the risk of M. ovipneumoniae infection of bighorn sheep; one approach to this objective is to control the pathogen in its reservoir hosts. Methods: The safety and immunogenicity of M. ovipneumoniae for domestic sheep was evaluated in three experimental immunization protocols: 1) live M. ovipneumoniae (50 ug protein); 2) killed M. ovipneumoniae (50 ug whole cell protein) in oil adjuvant; and 3) killed M. ovipneumoniae (250 ug whole cell protein) in oil adjuvant. Immunogenicity was assessed by two serum antibody measures: competitive enzyme-linked immunosorbent assay (cELISA) (experiments 1-3) and serum growth inhibition (Experiment 3). Passive immunogenicity was also assessed in the third experiment using the same assays applied to blood samples obtained from the lambs of immunized ewes. Results and Conclusions: Adverse reactions to immunization were generally minor, but local reactions were regularly observed at immunization sites with bacterins in oil adjuvants. No evidence of M. ovipneumoniae specific antibody responses were observed in the first or second experiments and no resistance to colonization was observed in the first experiment. However, the ewes in the third experiment developed strong cELISA serum antibody responses and significant serum M. ovipneumoniae inhibition activity, and these responses were passively transferred to their lambs. The results of these trials indicate that immunization with relatively large antigenic mass combined with an adjuvant is capable of inducing strong active antibody responses in ewes and passively immunizing lambs.

Journal of Dairy Science, 1997

The objective of this study was to identify and evaluate expression of IgG 1 receptors by differe... more The objective of this study was to identify and evaluate expression of IgG 1 receptors by different cell types in mammary tissue sections and digestdispersed cells from the bovine mammary gland. An immunohistochemical system utilizing avidin-biotinperoxidase complex demonstrated epithelial expression of IgG 1 receptors in mammary tissue sections from cows producing colostrum but not from cows in lactation. Fluorescence flow cytometry demonstrated that cells dispersed in digests from both tissues producing colostrum and lactating tissues selectively bound IgG 1. Fluorescence flow cytometry, using monoclonal antibodies to cell surface molecules, cytokeratin, and IgG 1 , revealed that leukocytes constituted the largest percentage of cells and were the predominant cell type binding IgG 1 in mammary tissue digests. Although IgG 1 binding to epithelial cells predominated in the gland during colostrum production in situ, digestion and filtration to produce single cell suspensions resulted in the loss of large numbers of epithelial cells. Studies of Ig binding of cells produced by enzymatic digestion must account for the types of cells surviving the digestion process.