Risk factors for new intramammary infections during the dry period in untreated dairy cows from herds using selective dry cow therapy.

This study aimed at investigating risk factors for new intramammary infections (IMI) during the dry period in untreated cows from herds using selective dry cow antibiotic therapy (DCT). A total of 980 uninfected quarters in 347 untreated cows from 28 herds using selective DCT were included in a prospective survey. A herd-level questionnaire and an individual cow-level recording sheet were implemented to collect data on putative risk factors.

Shedding routes of Coxiella burnetii in dairy cows: implications for detection and control.

Reliable detection of Coxiella burnetii shedders is a critical point for the control of the spread of this bacterium among animals and from animals to humans. Coxiella burnetii is shed by ruminants mainly by birth products (placenta, birth fluids), but may also be shed by vaginal mucus, milk, and faeces, urine and semen. However, the informative value of these types of samples to identify shedders under field conditions is unknown.

Interdependence of udder quarters for new intramammary infection during the dry period in cows submitted to selective antibiotic therapy.

The aim was to investigate the interdependence of udder quarters within cow towards the incidence of intramammary infections during the dry period in herds under selective dry-cow antibiotic therapy. A total of 368 cows among 28 herds were included in a survey. Quarter milk samples collected at the last milking before drying-off and on day 3 after calving were submitted to microbiological procedures.

Incidence of respiratory disorders during housing in non-weaned Charolais calves in cow-calf farms of Pays de la Loire (Western France).

We assessed the incidence rate of respiratory disorders during the 1999-2000 housing period in non-weaned calves reared in a specific cow-calf farming system in western France, examined its variations according to age of the calf, housing facility and meteorological conditions, and described the different time-distribution patterns of incident cases within the barns. Treatments for respiratory disorders were recorded by the farmers on a specific sheet according a written definition provided. A case "occurred" on a given day if the calf concerned was treated for respiratory disorder on this day but not in the previous 14 days.

A model of the spread of the bovine viral-diarrhoea virus within a dairy herd.

Wet BVDSim (a stochastic simulation model) was developed to study the dynamics of the spread of the bovine viral-diarrhoea virus (BVDV) within a dairy herd. This model took into account herd-management factors (common in several countries), which influence BVDV spread. BVDSim was designed as a discrete-entity and discrete-event simulation model.