Objective—To assess selenium (Se) status of cats in
4 regions of the world and to compare results for Se
status with reported incidence of hyperthyroidism in
cats in those regions.
Animals—50 cats (30 from 2 regions with an allegedly
high incidence of hyperthyroidism and 20 from 2 regions
in which the disease is less commonly reported).
Procedure—Hematologic samples (heparinized
whole blood, plasma, and RBC fractions) were
obtained from 43 healthy euthyroid cats and 7 hyperthyroid
cats. Plasma concentration of Se and activity
of glutathione peroxidase (GPX) in whole blood and
plasma were determined.
Results—Plasma concentration of Se and GPX activity
in whole blood or plasma did not differ significantly
among cats from the 4 regions. However, cats had
a plasma concentration of Se that was approximately
10 times the concentration reported in rats and
humans. The GPX activity in whole blood or plasma in
cats generally was higher than values reported in rats
Conclusions and Clinical Relevance—Cats have
higher Se concentrations in plasma, compared with
values for other species. However, Se status alone
does not appear to affect the incidence of hyperthyroidism
in cats. High Se concentrations may have
implications for health of cats if such concentrations
are influenced by the amount of that micronutrient
included in diets. (Am J Vet Res 2001;62:934–937)
Objective—To determine the prevalence of Mycoplasma bovis infection in the lungs of cattle at various times after arrival at a feedlot, to measure the relationship between clinical disease status and the concentration and genotype of M bovis within the lungs, and to investigate changes in the genotype of M bovis over time.
Sample—Bronchoalveolar lavage fluid (BALF) from 328 healthy or pneumonic beef cattle and 20 M bovis isolates obtained from postmortem samples.
Procedures—The concentration of M bovis in BALF was determined via real-time PCR assays, and M bovis isolates from BALF were genotyped via amplified fragment length polymorphism (AFLP) analysis.
Results—Prevalence of M bovis in BALF was 1 of 60 (1.7%) at arrival to a feedlot and 26 of 36 (72.2%) and 36 of 42 (85.7%) at ≤ 15 days and 55 days after arrival, respectively. Neither the concentration nor the AFLP type of M bovis in BALF was correlated with clinical disease status. The M bovis AFLP type differed between early and later sampling periods in 14 of 17 cattle.
Conclusions and Clinical Relevance—The findings implied spread of M bovis among calves and suggested that host factors and copathogens may determine disease outcomes in infected calves. Chronic pulmonary infection with M bovis may represent a dynamic situation of bacterial clearance and reinfection with strains of different AFLP type, rather than continuous infection with a single clone. These findings impact our understanding of why cattle with chronic pneumonia and polyarthritis syndrome inadequately respond to antimicrobial treatment.