Bovine acute mastitis: effects of intravenous sodium salicylate on endotoxin-induced intramammary inflammation

An Update on the Effect of Clinical Mastitis on the Welfare of Dairy Cows and Potential Therapies

Despite the widespread implementation of mastitis control programs, mastitis is the most common and one of the costliest diseases in the dairy industry, with broad-ranging impacts and consequences. Recent technological advances have allowed researchers to assess the effects of mastitis on animal behavior and welfare, and the efficacy of mastitis treatments. Several nonsteroidal anti-inflammatory drugs are available as supportive therapies for clinical mastitis. This article focuses on recent advances in the assessment, therapy, and effects of mastitis on cow behavior and welfare.

Invited review: Inflammation during the transition to lactation: New adventures with an old flame

For dairy cattle, the first several weeks of lactation represent the highest-risk period in their lives after their own neonatal period. Although more than 50% of cows during this period are estimated to suffer from at least one subclinical disorder, the complicated admixture of normal adaptations to lactation, infectious challenges, and metabolic disorders has made it difficult to determine which physiological processes are adaptive and which are pathological during this time. Subacute inflammation, a condition that has been well documented in obesity, has been a subject of great interest among dairy cattle physiologists in the past decade. Many studies have now clearly shown that essentially all cows experience some degree of systemic inflammation in the several days after parturition. The magnitude and likely persistence of the inflammatory state varies widely among cows, and several studies have linked the degree of postpartum inflammation to increased disease risk and decreased whole-lactation milk production. In addition to these associations, enhancing postpartum inflammation with repeated subacute administration of cytokines has impaired productivity and markers of health, whereas targeted use of nonsteroidal anti-inflammatory drugs during this window of time has enhanced whole-lactation productivity in several studies. Despite these findings, many questions remain about postpartum inflammation, including which organs are key initiators of this state and what signaling molecules are responsible for systemic and tissue-specific inflammatory states. Continued in vivo work should help clarify the degree to which mild postpartum inflammation is adaptive and whether the targeted use of anti-inflammatory drugs or nutrients can improve the health and productivity of dairy cows.

CpG-ODN enhances mammary gland defense during mastitis induced by Escherichia coli infection in goats

Seven healthy native goats in early lactation, weighing 30-40 kg, were used in this study. The right mammary gland of the seven does were infused with CpG-ODN at a dosage of 100 microg kg(-1) body weight on the day 5 postpartum (PP). The left glands were used as controls and infused with sterile phosphate-buffered saline (PBS). On day 8 PP, the same dosage of CpG-ODN or PBS was again infused. On day 9 PP, the mammary glands (both right and left) of the seven does were infused with 6 x 10(6) colony-forming units (CFU) Escherichia coli and, at 0, 8, 16, 24, 48 and 72 h postinfection (PI), milk samples were collected from all glands. Goats were euthanized at 72 h PI and the mammary tissue harvested. Infusion with 6 x 10(6)CFU ml(-1)E. coli induced acute mastitis. Histopathological evaluations showed that polymorphonuclear neutrophils (PMNs) were still present in alveoli at 72 h PI, but PMNs in the CpG-ODN-treated glands has disappeared. Bacteria counts in milk peaked at 16 h PI and CpG-ODN induced a significant decrease in viable bacteria from 16 h PI until the end of the experiment. This study showed that CpG-ODN promoted the expression of its specific receptor (TLR-9 mRNA) in mammary tissue, stimulated IL-6 production, reduced bacteria counts in milk, attenuated the impact of inflammation mediators on cells and significantly shortened the inflammation course. These results suggest that the CpG-ODN improved mammary gland defense and, thereby, had a beneficial effects against mastitis caused by E. coli infection in goats.

The pharmacokinetics of salicylate in dairy cattle are not altered by simultaneous intravenous ceftiofur sodium and DL-lysine-acetyl salicylate (aspirin)

This study evaluated potential alterations to the pharmacokinetics of salicylate by concurrently administered ceftiofur sodium. The trial design was a cross-over using 10 non-lactating, non-pregnant dairy cows. In the first period each cow received intravenously (i.v.) 26 mg/kg of DL-lysine acetyl salicylate (aspirin) followed immediately by 2 mg/kg ceftiofur sodium. In the second period each cow received 26 mg/kg of aspirin i.v. Plasma samples were harvested for determination of salicylate concentration by HPLC. The data best fitted a single compartment open model, using weighted non-linear regression. No alterations to the pharmacokinetic parameters of salicylate in cattle by concurrently administered ceftiofur sodium were detected (P < 0.05). Using 90% confidence intervals, and testing for changes of > 20%, control values, elimination half-life (t1/2), apparent volume of distribution (Vd), area under the plasma concentration versus time curve (AUC) and mean residence time (MRT) were not altered. For control animals the elimination rate constant (k(el)) and total body clearance (Cl) were 1.35 +/- 0.43 h-1 and 20.2 +/- 6.1 ml/h.kg respectively (mean +/- SD). Since ceftiofur sodium did not affect the pharmacokinetics of salicylate, dose regimens for aspirin in cattle need not be altered when ceftiofur sodium is administered concurrently.

Non-steroidal anti-inflammatory drugs and spinal nociceptive processing

Non-steroidal anti-inflammatory drugs have a direct action on spinal nociceptive processing in vivo with a relative order of potency which correlates with their capacity as inhibitors of cyclooxygenase activity. However, recent clinical surveys and new in vivo evidence strongly suggest that for some of these agents, centrally mediated analgesia may also be achieved by additional mechanisms, which are independent of prostaglandin synthesis inhibition. In this review we explore the likelihood for such mechanisms following an extensive survey of existing data. The implications of these mechanisms are discussed in the light of our current understanding of spinal nociceptive processing.