RESUMO
This study investigated the metabolic effects of glucocorticoids when administered to propylene glycol-treated cows with clinical ketosis. Clinical ketosis was defined by depressed feed intake and milk production, and a maximal score for acetoacetate in urine. All cows received 250 mL oral propylene glycol twice daily for 3 days and were randomly assigned to a single intramuscular injection with sterile isotonic saline solution (n = 14) or dexamethasone-21-isonicotinate (n = 17). Metabolic blood variables were monitored for 6 days and adipose tissue variables for 3 days. ß-Hydroxybutyrate (BHBA) concentrations in blood decreased in all cows during treatment, but were lower in glucocorticoid-treated cows. Cows treated with glucocorticoids had higher plasma glucose and insulin concentrations, whereas concentrations of non-esterified fatty acids, 3-methylhistidine and growth hormone were unaffected. mRNA expression of hormone-sensitive lipase, BHBA receptor and peroxisome proliferator-activated receptor type γ in adipose tissue was not affected. This shows that lipolytic effects do not appear to be important in ketotic cows when glucocorticoids are combined with PG. Plasma 3-methyl histidine concentrations were similar in both groups, suggesting that glucocorticoids did not increase muscle breakdown and that the greater rise in plasma glucose in glucocorticoid-treated cows may not be due to increased supply of glucogenic amino acids from muscle.
Assuntos
Doenças dos Bovinos/tratamento farmacológico , Isonicotinato de Dexametasona/uso terapêutico , Glucocorticoides/uso terapêutico , Cetose/veterinária , Propilenoglicol/uso terapêutico , Animais , Bovinos , Isonicotinato de Dexametasona/administração & dosagem , Quimioterapia Combinada , Feminino , Glucocorticoides/administração & dosagem , Insulina/sangue , Cetose/tratamento farmacológico , Metilistidinas/sangue , Propilenoglicol/administração & dosagemRESUMO
Mycobacterium avium subsp. paratuberculosis, the causative agent of Johne's disease in cattle, was identified in settled-dust samples of Dutch commercial dairy farms, both in the dairy barn and in the young stock housing. Bioaerosols may play a role in within-farm M. avium subsp. paratuberculosis transmission.