Systemic Treatment of Subclinical Mastitis in Lactating Cows with Penethamate Hydriodide

Abstract

A randomized controlled field trial was performed to evaluate the efficacy of a 3-d treatment regimen with i.m. penethamate hydriodide compared with no treatment in lactating cows with subclinical mastitis. To be included, a cow had to have 2 somatic cell counts (SCC) 300,000 cells/mL at the last 3 monthly controls, 1 or more quarters with SCC >250,000 cells/mL, and the same bacterial species isolated in 2 consecutive samples 2 to 4 d apart. A total of 151 quarters from 92 cows were monitored for 2 mo following treatment. Quarter milk samples were examined for bacteriological cure (BC) and SCC at 14, 28, and 60 d after treatment. Bacteriological cure was defined as not having the same bacterial species isolated from the quarter milk samples taken at 14 and 28 d posttreatment as in the samples taken before treatment. Systemic treatment with penethamate resulted in BC in 59.5% of quarters and 52.2% of cows, compared with 16.7 and 10.9% in the untreated cows. Somatic cell count decreased significantly in the penethamate-treated cows, steadily in the case of BC and transiently when the infections persisted. This study confirms that systemic treatment of subclinical mastitis with penethamate is effective and that BC of infected quarters has a sustained positive effect on milk SCC during the 2 mo following treatment.

Evaluation of the efficacy of intramuscular versus intramammary treatment of subclinical Streptococcus agalactiae mastitis in dairy cows in Colombia

“…The efficacy of the IM penethamate-based product was 65.8% in our study, which was higher than reported by Salat et al (2008). The earlier study considered subclinical mastitis produced by several mastitis pathogens (S. aureus, CNS S. uberis, non-S. agalactiae streptococci, and Corynebaterium bovis).…”

“…Other possible predictors of interest not measured in our trial, for example DIM and parity, could affect the cure risks in both treatments. Related to these 2 variables, other authors have reported no influence of the stage of lactation on the cure risk for the penethamate or negative control groups for non-agalactiae streptococci, S. aureus, and CNS (Salat et al, 2008). In contrast, another group of authors reported that for S. aureus treatment, increasing parity was associated with lower cure risk (Barkema et al, 2006).…”

“…In addition, including herd as a random effect will help to control for other unmeasured confounders that cluster at the farm level. A previous study found no effect of DIM on the cure risk for streptococci and other major pathogens (Salat et al, 2008); however, the present study did not control by these variables due to the difficulties retrieving the individual records for the cows. In addition, the logistic model presented in our study included herd as random effect, and this will also reduce the effect of herd-level unmeasured confounders.…”

“…The earlier study considered subclinical mastitis produced by several mastitis pathogens (S. aureus, CNS S. uberis, non-S. agalactiae streptococci, and Corynebaterium bovis). When evaluated against a negative control, treatment with IM penethamate had a bacteriological cure risk of 52.2 compared with 10.9% in the control group (Salat et al, 2008). The present study focused on S. agalactiae only, and therefore the cure risk would be expected to be higher when compared with other major pathogens, such as S. aureus.…”

Concentration of penicillin G in mammary tissue and secretion of end-term dairy heifers following systemic prepartum administration of penethamate hydriodide

“…administration of penethamate hydriodide for 3 d can be efficacious in the treatment of clinical and subclinical mastitis in lactating cows (Serieys et al 2005;Salat et al 2008). administration of penethamate hydriodide for 3 d can be efficacious in the treatment of clinical and subclinical mastitis in lactating cows (Serieys et al 2005;Salat et al 2008).…”