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Abstract

Objective—To characterize rib, intrathoracic, and concurrent orthopedic injuries, and prognosis associated with traumatic rib fracture in cats.

Design—Retrospective study.

Animals—75 cats.

Procedure—Medical records from January 1980 to August 1998 were examined for cats with traumatic rib fracture. Signalment, cause of trauma, interval from trauma to evaluation at a veterinary teaching hospital, referral status and date, method of diagnosis, duration of hospitalization, number and location of rib fractures, presence of flail chest, costal cartilage involvement, intrathoracic and concurrent orthopedic injury, and clinical outcome were reviewed.

Results—Median age was 3 years. Twenty-five (58%) cats with reported cause of trauma were injured by interaction with another animal. Fortyseven (78%) cats that were treated survived. Cats that died had a median duration of hospitalization of < 1 day. Ten (13%) cats had flail chest. Sixty-five (87%) cats had intrathoracic injury (median, 2 injuries). Nine (100%) cats without detected intrathoracic injury that were treated survived. Thirty-five (47%) cats had concurrent orthopedic injury. Cats with flail chest, pleural effusion, or diaphragmatic hernia were significantly more likely to die than cats without each injury.

Conclusions and Clinical Relevance—Traumatic rib fracture in cats is associated with intrathoracic and concurrent orthopedic injury. Aggressive treatment of cats with traumatic rib fracture is warranted, because the prognosis is generally favorable. Diagnosis and treatment of intrathoracic injury associated with traumatic rib fracture in cats should precede management of concurrent orthopedic injury. ( J Am Vet Med Assoc 2000;216:51–54)

Full access
in Journal of the American Veterinary Medical Association

Abstract

Objective—To study the local immune response of calves to bovine respiratory syncytial virus (BRSV) infection with emphasis on IgE production and cytokine gene expression in pulmonary lymph.

Animals—Twelve 6- to 8-week-old Holstein bull calves. Six similar control calves were mock infected to obtain control data.

Procedure—Lymphatic cannulation surgery was performed on 12 calves to create a long-term thoracic lymph fistula draining to the exterior. Cannulated calves were exposed to virulent BRSV by aerosol. Lymph fluid collected daily was assayed for BRSV and isotype-specific IgE antibody, total IgG, IgA, IgM, and protein concentrations. Interleukin-4 (IL-4), interleukin- 2 (IL-2), and interferon-γ were semi-quantitated by reverse transcription-polymerase chain reaction (RT-PCR). Cell counts and fluorescence-activated cell scanner (FACSCAN) analysis of T-cell subsets were performed on lymph cells.

Results—Calves had clinical signs of respiratory tract disease during days 5 to 10 after infection and shed virus. Bovine respiratory syncytial virus-specific IgE in infected calves was significantly increased over baseline on day 9 after infection. Mean virus-specific IgE concentrations strongly correlated with increases in severity of clinical disease (r = 0.903). Expression of IL-2, IL-4, and interferon-γ was variably present in infected and control calves, with IL-4 expression most consistent during early infection.

Conclusions and Clinical Relevance—Infection with BRSV was associated with production of BRSV-specific IgE, and IL-4 message was commonly found in lymph cells of infected calves. This finding supports the concept that BRSV-induced pathophysiology involves a T helper cell type-2 response. Effective therapeutic and prophylactic strategies could, therefore, be developed using immunomodulation to shift the immune response more toward a T helper cell type-1 response. (Am J Vet Res 2000;61:291–298)

Full access
in American Journal of Veterinary Research

Objective—

To determine whether heifers with naturally acquired congenital exposure to Neospora sp would transmit the infection to their offspring during gestation.

Design—

Prospective cohort study.

Animals—

Neonatal heifers on a dairy with a history of Neospora sp infections were selected for the study on the basis of their serum titers to Neospora sp, as determined by the use of indirect fluorescent antibody testing. Seropositive heifers (n = 25) had titers ≥ 1:5,120 and seronegative heifers (25) had titers ≤ 1:80. All heifers were raised and bred on the dairy, and samples were obtained from heifers and their calves at the time of calving.

Procedure—

Blood samples were tested for Neospora sp antibodies. Histologic evaluations, Neospora sp immunohistochemical examinations. and protozoal culturing were performed on samples obtained from selected offspring (second-generation calves).

Results—

Seropositive heifers gave birth to calves with titers ≥ 1:1,280 to Neospora sp. All offspring from seropositive heifers that were necropsied had evidence of Neospora sp infection. All seronegative heifers and their offspring had titers < 1:80 to Neospora sp.

Clinical Implications—

Congenitally acquired Neospora sp infection can persist in clinically normal heifers and be transmitted transplacentally to their offspring. Vertical transmission can be a way by which neosporosis is maintained in herds. (J Am Vet Med Assoc 1997;210:1169–1172)

Free access
in Journal of the American Veterinary Medical Association

Summary:

Four dairy cows that had been successfully rebred following fetal Neospora infection and abortion were identified from 2 drylot dairies. All 4 cows had uncomplicated pregnancies with the birth of 5 full-term calves. The calves all had high precolostral serum IgG antibodies. The precolostral antibodies to Neospora sp as determined by indirect fluorescent antibody test ranged from 5,120 to 20,480, compared with maternal serum and colostral antibody titers from 320 to 1,280. Two calves had mild neurologic limb deficits. Three calves had mild nonsuppurative encephalomyelitis and Neospora organisms were found in the CNS of 3 calves. Findings indicate that repeat transplacental Neospora infections occur in cows. Additionally, calves born from cows with a history of Neospora fetal infection and abortion may have congenital Neospora infections and/or neurologic dysfunctions at birth. The Neospora indirect fluorescent antibody test appears to be a useful antemortem test for detection of calves exposed in utero to Neospora organisms.

Free access
in Journal of the American Veterinary Medical Association

SUMMARY

Leukocytosis (34,600 wbc/μl of blood) was detected in an apparently healthy 7-day-old Holstein heifer. Analysis of blood samples obtained over the next 41 days revealed chronic progressive neutrophilia, which peaked at > 85% neutrophils and exceeded 100,000 wbc/μl. In vitro assessment of isolated blood neutrophils obtained from the heifer at 38 and 45 days of age revealed selected functional abnormalities. Endocytosis of immunoglobulin-opsonized Staphylococcus aureus and killing of this test organism by the calf’s neutrophils were significantly diminished, as were phagocytosis-associated superoxide generation, chemiluminescence activity, and myeloperoxidase-catalyzed iodination. Diminished H2O2 elaboration by the calf’s neutrophils was evident during ingestion of opsonized zymosan or on exposure to phorbol myristate acetate. Extracellular release (secretion) of elastase during ingestion of zymosan was also diminished, although total cell content of elastase was normal, compared with that of neutrophils from age-matched calves, and granular or other morphologic abnormalities of the calf’s neutrophils were not evident by ultrastructural examination. Abnormalities of random migration were inconsistently detected, and normal or high degree of antibody-dependent cytotoxicity or natural killing by the calf’s neutrophils was observed. Similar in vitro assessment of neutrophils obtained from the calf’s dam revealed no functional abnormalities. The calf died at 48 days of age, with persistent fever and chronic diarrhea, despite administration of antibiotics. Histologic examination at necropsy revealed large numbers of intravascular neutrophils in most tissues, including massive neutrophil sequestration in spleen. However, a striking lack of extravascular neutrophils was evident in inflamed submucosa adjacent to intestinal ulcers heavily contaminated with enteric microorganisms. Bone marrow examination revealed diffuse myeloid hyperplasia, but no other abnormalities.

The clinical and pathologic features in this calf were similar to those in previously reported human patients or Irish Setters with genetic deficiency of the CD11/CD18 leukocyte glycoprotein complex, thus prompting further postmortem evaluations. Results of immunoblot analyses of the neutrophil lysates of the heifer calf (isolated and stored prior to death) documented severe deficiency of Mac-1 (CD11b/CD18). Results of immunofluorescent analyses indicated substantially diminished (intermediate) amounts ofthe Mac-1 β subunit (CD18) on blood neutrophils of the calf's dam and sire and on neutrophils of 8 of 15 paternal half-siblings; findings were consistent with an autosomal recessive trait in the proband's kindred. Findings also indicate that genetic abnormalities of CD11/CD18 proteins may underlie the molecular pathogenesis of disease in this calf as well as other previously described examples of the granulocytopathy syndrome in Holstein cattle.

Free access
in American Journal of Veterinary Research

Abstract

Objective

To develop a model of bovine respiratory syncytial virus (BRSV) infection that induces severe disease similar to that seen in some cattle with naturally acquired BRSV infection.

Animals

25 male Holstein calves, 8 to 16 weeks old.

Procedure

17 calves were given a low-passage field isolate of BRSV by aerosolization; 8 control calves were given supernatant from noninfected cell culture. Disease was characterized by evaluating clinical signs, virus isolation and pulmonary function tests, and results of blood gas analysis, gross and histologic postmortem examination, and microbiologic testing.

Results

Cumulative incidence of cough, harsh lung sounds, adventitious sounds, and dyspnea and increases in rectal temperature and respiratory rate were significantly greater in infected calves. Three infected calves developed extreme respiratory distress and were euthanatized 7 days after inoculation. Virus was isolated from nasal swab specimens from all infected calves but not from mock infected calves. On day 7 after inoculation, mean Pao2 and Paco2 were significantly lower, and pulmonary resistance was significantly higher, in infected calves. During necropsy, infected calves had varying degrees of necrotizing and proliferative bronchiolitis and alveolitis with syncytial formation. The 3 calves euthanatized on day 7 had emphysematous bullae in the caudal lung lobes; 1 had unilateral pneumothorax.

Conclusion and Clinical Relevance

Severe disease similar to that seen in some cattle with naturally acquired BRSV infection can be induced in calves with a single aerosol exposure of a low-passage clinical isolate of BRSV. Our model will be useful for studying the pathogenesis of BRSV infection and for evaluating vaccines and therapeutics. (Am J Vet Res 1999;60:473-480)

Free access
in American Journal of Veterinary Research

Objective—

To estimate the minimum rate of abortion attributable to infection with Neospora sp in selected California dairy herds.

Design—

Prospective study.

Animals—

Twenty-six dairy herds containing 19,708 cows were studied. Fourteen herds had a history of abortions attributable to neosporosis, and 12 were herds in which neosporosis had not been identified as a cause of abortions.

Procedure—

During a 1-year period, all available aborted fetuses were submitted to veterinary diagnostic laboratories to determine the cause of abortion. Reproductive records of cows that aborted were reviewed.

Results—

Neospora sp infection was the major cause of abortion identified (113/266 abortions, 42.5%). The majority (232/266, 87.2%) of the aborted fetuses were submitted from herds with a history of abortions attributable to neosporosis, and Neospora sp infection was identified as the causative agent in 101 of 232 (43.5%) of the abortions from these herds. Fewer aborted fetuses were submitted from the 12 herds that did not have a history of abortion attributable to Neospora sp; however, neosporosis was confirmed as a cause of abortion in 6 of these 12 herds and was identified as the causative agent in 12 of 34 (35.3%) abortions from these herds. The disease was widespread throughout the state (19/26 herds in our study). Available reproductive histories of cows that had abortions attributed to neosporosis were evaluated, and 4 cows were identified that twice aborted Neospora-in-fected fetuses.

Free access
in Journal of the American Veterinary Medical Association

Objective

To characterize and contrast data from Thoroughbreds that incurred a fatal musculoskeletal injury ( fmi; injury resulting in death or euthanasia) during racing or training and data from all California race entrants during a 9-month period in 1991.

Design

Case-control study.

Animals

Thoroughbreds that incurred a fmi during racing or training at a California race-meet and all California race entrants from January through June and October through December 1991.

Procedure

Age and sex were compared with χ2 and Fisher's exact tests among horses fatally injured while racing and training. A log-linear model was fit to assess the relationship between race-meet and age and sex of California race entrants. Incidence risk of racing fmi was estimated per 1,000 race entrants, and the relationship between the occurrence of fmi during racing with race-meet, age, and sex was evaluated by logistic regression.

Results

Injury type and sex-specific age distributions differed among the horses fatally injured during racing and training. Age and sex distributions of the race entrants were not independent and varied among race-meets. Overall incidence risk of racing fmi was estimated at 1.7/1,000 race entrants. Risk of racing fmi in male horses was about twofold that in female horses, and in 4-year-olds was twofold that in 3-year-olds.

Clinical Implications

Age- and sex-related differences in risk of incurring a fmi during racing should be considered when comparing fatal injury rates among race-meets.

Free access
in Journal of the American Veterinary Medical Association

Objective

To investigate relationships of several racehorse characteristics and race conditions with risk of a catastrophic musculoskeletal injury (CMI) resulting in euthanasia in Thoroughbreds during racing in California in 1992.

Design

Retrospective longitudinal study.

Animals

Thoroughbreds that incurred CMI during racing and all California race entrants in 1992.

Procedure

Necropsy records were reviewed, and race start information was obtained. Incidence risk of CMI/1,000 race entrants was estimated. Relationships between CMI during racing and race-meet, entrant age and sex, race type and length, and racing surface type and condition were evaluated by use of logistic regression.

Results

Incidence risk of CMI was 1.7/1,000 entrants. A higher risk of CMI was found at 2 fair race-meets, with incidence risks of 4.9 and 5.5/1,000 entrants. Risk of injury in male horses was 1.7 times greater than that in female horses, and influence of age on risk depended on race type. Risk of injury for horses 2 to 5 years old was two times greater for claiming horses than for maiden horses. Race length or racing surface type (dirt vs turf) or condition (fast, muddy, yielding) were not significantly associated with risk of CMI.

Clinical Implications

Incidence of CMI was similar among 12 of 14 major and fair race-meets and among various race lengths and racing surface types and conditions, whereas incidence of CMI was influenced by entrant age and sex as well as race type. Investigators should consider controlling for age and sex, race-meet, and race type whenever possible in studies of risk of CMI. (J Am Vet Med Assoc 1998; 212:544-549)

Free access
in Journal of the American Veterinary Medical Association

Abstract

Objective

To evaluate hoof size, shape, and balance as risk factors for catastrophic musculoskeletal injuries (CMI), including suspensory apparatus failure (SAF) and cannon bone condylar fracture (CDY) in Thoroughbred racehorses.

Animals

95 Thoroughbred racehorses that died between 1994 and 1996.

Procedure

38 quantitative measures of hoof size, shape, and balance were obtained from orthogonal digital images of the hoof and were compared between case horses with forelimb CMI (70), SAF (43), and CDY (10) injuries and control horses whose death was unrelated to the musculoskeletal system (non-CMI, 25). Comparison of group means between cases and controls was done using ANOVA, and multivariable logistic regression was used to estimate odds ratios.

Results

Odds of CMI were 0.62 times lower for a 5- mm increase in ground surface width difference and 0.49 times lower for a 100-mm2 increase in sole area difference. Odds of SAF were 6.75 times greater with a 10° increase in toe-heel angle difference and 0.58 times lower with a 100-mm2 increase in sole area difference. Odds of CDY were 0.26 times lower with a 3° increase in toe angle, 0.15 times lower with a 5- mm increase in lateral ground surface width, and 0.35 times lower with a 100-mm2 increase in sole area difference.

Clinical Relevance

Decreasing the difference between toe and heel angles should decrease risk of SAF for Thoroughbred racehorses and should be considered in addition to increasing toe angle alone to help prevent catastrophic injury. Trimming the hoof to perfect mediolateral symmetry may not be a sound approach to avoiding injury. (Am J Vet Res 1998;59: 1545-1552)

Free access
in American Journal of Veterinary Research