Outbreak of pneumonia and arthritis in beef calves associated with Mycoplasma bovis and Mycoplasma californicum

During an outbreak of pneumonia and arthritis in beef calves and young cattle on a large farm in north-west Germany, Mycoplasma bovis and Mycoplasma californicum were isolated from tracheobronchial lavage fluids and synovial fluids. The microbiological findings in dead and living animals and the immunohistochemical demonstration of M californicum antigen in lung and arthritic joint tissue, indicated that under poor housing conditions and possibly other predisposing factors, this mycoplasma, like M bovis, can colonise the respiratory tract and may be able to cross the respiratory mucosal barrier to spread through an infected animal and cause systemic infections that may contribute to severe arthritis.     

Chronic pneumonia and polyarthritis syndrome in a feedlot calf

A feedlot heifer was diagnosed with chronic pneumonia and polyarthritis syndrome (CPPS), which was confirmed on postmortem examination. The syndrome is caused by Mycoplasma bovis; however, available data support the theory that other pathogens play a role in predisposing to this disease. Continued research on CPPS focuses on pathogenesis, treatment, and prevention.     

An outbreak of chronic pneumonia and polyarthritis syndrome caused by Mycoplasma bovis in feedlot bison (Bison bison).

Mycoplasma bovis was identified by a specific lesion, conventional bacterial culture, immunohistochemistry, and polymerase chain reaction in 2 feedlot bison found dead with severe, chronic, caseonecrotic pneumonia; polyarthritis; and laryngitis. On microscopic examination, pulmonary lesions were characterized by prominent, well-defined areas of caseous necrosis and bronchiectasis. Immunohistochemical analysis of lung exhibited staining in bronchiolar epithelium and in random areas of caseous necrosis. On gross examination, the laryngeal lesion observed in 1 animal was typical of changes seen in cases of calf diphtheria. Nasal swabs taken from 6 clinically ill bison from the same feedlot revealed 1 animal shedding M. bovis by the nasal route. No other pathogens were recovered from the pulmonary or laryngeal lesions; however, Mannheimia haemolytica was cultured from the nasal swabs of 2 clinically ill bison, although not from the animal found to be shedding M. bovis. Several other affected bison had swollen joints and exhibited lameness and a reluctance to move. Changes observed in dead and clinically ill bison from this feedlot are similar to what has been described in the literature as chronic pneumonia and polyarthritis syndrome in feedlot cattle caused by M. bovis. Based on the severity of the lesions, and the number of dead and affected animals, bison in a feedlot setting appear to exhibit sensitivity to infection with M. bovis.     

The effect of early weaning on feedlot performance and measures of stress in beef calves

Forty crossbred steers (Brahman x English) were categorized into two groups: 1) early weaned (EW; n = 20); and 2) normal weaned (NW; n = 20). Calves were 89 and 300 d of age at the time of EW and NW, respectively; SEM = 4.4. Early-weaned calves were kept on-site (University of Florida, Ona), provided supplement (1% of BW), and grazed on annual and perennial pastures until NW. At the time of normal weaning, all calves were loaded on a commercial livestock trailer and transported to the North Carolina State University Research Feedlot in Butner (approximately 1,200 km). Upon arrival, calves were stratified by BW and randomly allotted to four pens per weaning age treatment. Individual calf BW and blood samples were collected at the time of normal weaning, on arrival at the feedlot (d 1; 24 h following weaning), and on d 3, 7, 14, 21, and 28 of the receiving period. Individual BW was collected at the start and end of the growing and finishing periods, and feed intake by pen was measured daily. As an estimate of stress during the receiving period, plasma was collected and analyzed for the acute-phase proteins, haptoglobin and ceruloplasmin. Early-weaned calves were lighter (P = 0.03) at normal weaning than NW calves (221 vs. 269 kg; SEM = 10.6). By d 28, EW calves tended (P = 0.12) to be lighter than NW calves (242 vs. 282 kg, respectively). Gain:feed was improved for EW compared with NW calves during both the receiving (G:F = 0.157 vs. 0.081) and growing (0.159 vs. 0.136) periods. There tended (P < 0.10) to be weaning age x day interactions for each acute-phase protein. Ceruloplasmin concentrations increased in NW, but not EW calves, and peaked on d 7 (27.6 and 34.2 mg/100 mL for EW and NW calves, respectively; P < 0.05). Haptoglobin concentrations increased in both groups and were greatest (P < 0.05) in NW calves on d 3 (7.63 vs. 14.86 mg of haptoglobin/hemoglobin complexing/100 mL). No differences in ADG or G:F were detected during the finishing phase; however, overall G:F was improved (P = 0.03) for EW vs. NW calves (0.155 vs. 0.136). Carcass measures, including backfat thickness, USDA yield grade, marbling score, and LM area, did not differ between treatments. These data imply that EW calves, which are maintained onsite before shipping, may be more tolerant to the stressors associated with transportation and feed yard entry. Early weaned calves, managed within the system described in this study, may have improved G:F.     

Naturally occurring cerebrospinal parelaphostronglylosis.

An isolated case and an outbreak of parelaphostrongylosis in goats are described. Signs included tetraparesis, hemiparesis, tetraplegia, spastic gait, scoliosis, vestibular strabismus, blindness, and death. Five cases were necropsied and nematodes were seen in the brain and spinal cord of four of these. Intact adult nematodes from two cases were identified as Parelaphostrongylus tenuis, the meningeal worm of white-tailed deer. Cerebrospinal fluid analysis from affected goats showed a moderately elevated protein content, evidence of hemorrhage, and mononuclear cell and eosinophil pleocytosis. Recoveries are recorded.     

Transmission of Mycoplasma dispar among calves collected and reared for beef production

Fortytwo calves, 28 to 117 days old, were collected from 23 dairy farms and transported in a lorry, allowing direct contact between the calves, to 8 calf rearing farms. The average transport time per calf was 4.5 h, ranging from 0.3 to 12.8 h. The calves were sampled by nasal swabbing for mycoplasmas first before loading and then immediately after transport. Thirteen of the calves were transferred to farm I. They were placed in individual pens in a separate room to themselves, and were sampled at intervals for a period of 4 weeks.Ten of the 42 calves (23.8 %) originating from 5 of the source farms were found initially positive for M. dispar with titers > 4 log₁₀ ecu; 3 of these 10 calves were delivered to farm I and 7 calves to 6 others of the 8 receiving farms. Three initially infected calved delivered to farms I continued to be positive throughout the follow-up period; among the 10 initially negative calves the frequency of detected infection, and the geometric mean titer (within parenthesis), developed so that on days 1, 7, 14, and 28 the figures were: 2 (2.5), 8 (4.3), 9 (4.7), and 10 (5.5), respectively.After transport 3 initially negative calves were found positive with low titers. Two of them were placed on farm I. In one of them positivity proved to be only transient; the case seems to represent a phenomenon of transfer of mycoplasmas without establishment of infection. In contrast, at least 4 (possibly 7) calves, negative both before and after transport–ascribed above to the group of 10 initially negative calves arriving on farm I–had in all likelihood caught the infection during the transport. Two of the 10 calves most likely caught the infection on the farm; for 3 calves the evidence was equivocal as to the 2 alternatives.Seven of the 42 calves (16.7 %) were found to be initially infected with M. bovir-hinis, 2 of the 42 with Acholeplasma laidlawii. Among the 13 calves transported to an reared on farm I, 8 were found to be positive at least once for M. bovirhinis during the study. Colonisation by this mycoplasma was partly detected only intermittently and the detectable prevalence among the 13 calves at its highest was only 38.5 %.     

Factors associated with morbidity and mortality in feedlot calves: the Bruce County beef project, year two.

The results of the second year of the project confirmed most of the major findings from the initial year. Feeding cornsilage, particularly as the major roughage in the first month after arrival was associated with excess mortality. Mixing of cattle from different sources and vaccinating against respiratory disease appeared to be the most important additional factors that increased mortality rates. Delaying vaccination at least two days postarrival may have prevented the negative effects of vaccination but only in calves fed cornsilage. Morbidity rates were highly variable among farms but were positively correlated with mortality rates and treatment costs. The occurrence of infectious thromboembolic meningoencephalitis appeared to share some of the same risk factors as mortality; whereas, urolithiasis did not. Water deprivation may be a risk factor in the occurrence of urolithiasis. Fibrinous pneumonia was again the most frequent cause of death. Relative to year one, infectious thromboembolic meningoencephalitis increased in frequency and only one death was attributed to bovine virus diarrhea.     

Coinfection with bovine viral diarrhea virus and Mycoplasma bovis in feedlot cattle with chronic pneumonia

Chronic, antibiotic-resistant pneumonia, sometimes with concurrent polyarthritis, occurs in feedlot cattle in western Canada. The prevalence of Mycoplasma bovis, bovine viral diarrhea virus, and Haemophilus somnus was determined by using immunohistochemical staining of lung and heart tissue from 2 groups of animals with this history. Mycoplasma bovis antigen was present in 44/48 cases submitted between 1995 and 1998 (retrospective group) and 15/16 of cases from 1999 (prospective group), and was associated with pulmonary necrosis. Bovine viral diarrhea virus antigen was present in association with microscopic vascular lesions in 31/48 retrospective and 9/16 of prospective cases. Types Ib and II bovine viral diarrhea virus were isolated from 4/16 prospective cases. Haemophilus somnus antigen was present in heart, lung, or both of 15/48 retrospective and 8/16 prospective cases. The results suggest that there may be synergism between bovine viral diarrhea virus and M. bovis in this pneumonia with arthritis syndrome.     

Mycoplasma otitis in California calves.

A retrospective study of Mycoplasma otitis in California calves submitted for necropsy between 1993 and 2002 was conducted to characterize the demographic features of the disease and the pathologic findings associated with infection. Sixty-one confirmed cases of Mycoplasma otitis were identified among 20,525 necropsied cattle. All affected animals were calves, ranging in age from 2 weeks to 4 months and with a median age of 1.5 months. Ninety-two percent of the cases were dairy breeds. A higher percent of necropsied calves with Mycoplasma otitis were males (0.45%) than females (0.23%). The proportion of cases that had Mycoplasma otitis increased from 1993 to 2002, and there was a significant (P < 0.05) seasonal distribution, with the highest proportion in the spring and the lowest in the summer months. Infections involved both the middle and inner ear and were characterized by a suppurative inflammatory response with extensive bony involvement. Three species of Mycoplasma were isolated from the ears: M. bovis, M. bovirhinis, and M. alkalescens. Concurrent pneumonia occurred in 47 cases (77%), and Mycoplasma was isolated from the lungs of 30 of those cases. The increasing proportion of Mycoplasma otitis cases in the past 10 years emphasizes the importance of identifying risk factors that could be modified to lower the incidence of this disease in calves.