Comparison of results for commercially available microbiological media plates with results for standard bacteriologic testing of bovine milk.

Objective: To compare results for 3 commercially available microbiological media plates with those for standard bacteriologic testing of bovine milk.

Sample: Milk samples from postpartum cows and cows with a high somatic cell count (SCC) or clinical mastitis (CM).

Procedures: Sample-ready Staphylococcus culture medium (SRSC) plates were used to detect Staphylococcus aureus in milk samples obtained from postpartum cows and cows with a high SCC or CM.

A field study on the effects of dietary monensin on milk production and milk composition in dairy cows.

The objectives of this study were to quantify the effect of 16 ppm of dietary monensin on milk production and composition of dairy cows, and to investigate factors having a potential impact on this effect. Data were generated from a total of 3577 Holstein dairy cows (47 herds) in Quebec enrolled in a herd-level, randomized clinical trial investigating the effects of monensin supplementation. Milk production and composition data were collected from monthly dairy herd improvement (DHI) testing.

Efficacy of a 5-day extended therapy program during lactation with cephapirin sodium in dairy cows chronically infected with Staphylococcus aureus.

This study determined the efficacy of a 5-day extended therapy with cephapirin sodium in dairy cows chronically infected with Staphylococcus aureus. Chronically infected cows selected from 14 dairy herds in the St-Hyacinthe region, Québec were randomly allocated to a group of 31 cows treated for 5 consecutive days with 200 mg of cephapirin per quarter BID or a group of 30 untreated control cows. Bacteriological cure was determined by 3 negative bacterial cultures at 10, 24, and 31 days after treatment.

Health status and risk factors associated with failure of passive transfer of immunity in newborn beef calves in Québec.

Risk factors associated with failure of passive transfer of immunity (FPT) were evaluated among newborn beef calves in Québec. Physical examination was performed on calves born of a normal calving and blood samples were collected for determination of health status and measurement of serum concentration of immunoglobulin (Ig) G1. Of 225 calves, from 45 herds, 19% showed FPT (serum IgG1 concentration < 10.