Objective—To determine prevalence of papillomatous
digital dermatitis (PDD) among culled adult dairy
and beef cattle in the southeastern United States.
Animals—815 cattle examined during 4 visits to a
Procedure—The left hind foot of each animal was
examined for gross lesions of PDD. Breed and sex of
the animals were recorded. Lesions were examined
histologically for pathologic changes and bacteria,
Results—22 of 76 (29%) dairy cattle and 29 of 739
(4%) beef cattle had gross lesions of PDD. Detection
of lesions was not associated with sex of dairy cattle,
but male beef cattle were more likely to have lesions
of PDD than were female beef cattle. Histologically,
acute and chronic lesions were seen; the most severe
changes were localized to the stratum corneum.
Spirochetes were seen in lesions from 31 of 51 (61%)
Conclusions and Clinical Relevance—Results suggest
that PDD is common among culled adult cattle.
Prevalence was higher in culled adult dairy cattle than
in culled adult beef cattle. (J Am Vet Med Assoc
Objective—To determine whether a single intranasal
dose of modified-live bovine respiratory syncytial
virus (BRSV) vaccine protects calves from BRSV challenge
and characterize cell-mediated immune
response in calves following BRSV challenge.
Animals—13 conventionally reared 4- to 6-week-old
Procedure—Calves received intranasal vaccination
with modified live BRSV vaccine (VC-group calves;
n = 4) or mock vaccine (MC-group calves; 6) 1 month
before BRSV challenge; unvaccinated control-group
calves (n = 3) underwent mock challenge. Serum
virus neutralizing (VN) antibodies were measured on
days –30, -14, 0, and 7 relative to BRSV challenge;
nasal swab specimens were collected for virus isolation
on days 0 to 7. At necropsy examination on day 7,
tissue specimens were collected for measurement of
BRSV-specific interferon gamma (IFN-γ) production.
Tissue distribution of CD3+ T and BLA.36+ B cells
was evaluated by use of immunohistochemistry.
Results—The MC-group calves had significantly higher
rectal temperatures, respiratory rates, and clinical
scores on days 5 to 7 after BRSV challenge than VCgroup
calves. No difference was seen between distributions
of BRSV in lung tissue of VC- and MC-group
calves. Production of BRSV-specific IFN-γ was
increased in tissue specimens from VC-group calves,
compared with MC- and control-group calves. Virusspecific
IFN-γ production was highest in the mediastinal
lymph node of VC-group calves. Increased numbers
of T cells were found in expanded bronchialassociated
lymphoid tissue and airway epithelium of
Conclusions and Clinical Relevance—An intranasal
dose of modified-live BRSV vaccine can protect calves
against virulent BRSV challenge 1 month later. ( Am J Vet Res 2004;65:363–372)
Objective—To characterize cytokine messenger RNA
(mRNA) expression in intranasally vaccinated calves
after bovine respiratory syncytial virus (BRSV) challenge.
Animals—Twelve 8- to 12-week-old calves.
Procedures—Calves received modified-live BRSV vaccine
(vaccinated) or spent tissue culture medium
(mock-vaccinated) intranasally, followed by challenge
30 days later with BRSV, or mock challenge with spent
tissue culture medium (mock-challenge controls).
Interleukin-4 (IL-4) and interferon-γ (IFN-γ) mRNA was
measured in lungs, bronchoalveolar lavage (BAL) fluid
cells, pharyngeal tonsils, and tracheobronchial lymph
nodes, and tumor necrosis factor-α (TNF-α) mRNA was
measured in lungs and BAL fluid cells by reverse transcriptase-competitive
polymerase chain reaction assay.
Results—Resistance to clinical signs of disease was
conferred in vaccinated calves. Expression of TNF-α
mRNA in lungs and BAL fluid cells was higher in
mock-vaccinated calves than control or vaccinated
calves. In the lung, IL-4 mRNA expression was higher
in vaccinated calves than control or mock-vaccinated
calves. In pharyngeal tonsils, expression of mRNA for
IL-4 and IFN-γ was higher in mock-vaccinated calves
than control calves. In tracheobronchial lymph nodes,
IFN-γ mRNA expression was higher in mock-vaccinated
calves than vaccinated calves.
Conclusions and Clinical Relevance—Although vaccinated
calves had decreased clinical signs of disease after
BRSV challenge, compared with mock-vaccinated calves,
this difference was not related to a T helper type 1 bias,
as determined by increased expression of interferon-γ
mRNA relative to interleukin-4 mRNA in lungs, BAL fluid
cells, or tracheobronchial lymph nodes of vaccinated
calves. Pulmonary inflammation was decreased in vaccinated
calves as determined by decreased expression of
TNF-α mRNA. (Am J Vet Res 2004;65:725–733)