great lakes dairy sheep symposium - the Department of Animal ...

criteria with high penalties (over a given threshold) to determine milk price since 1993.
Therefore producer organizations and dairy plants have implemented a control plan for
subclinical mastitis in the Roquefort area. In Pyrenees mountains, the producers (except for the
home cheese makers) and the dairy industry give no particular attention to SCC.
4.3. Definition of a control program
To be efficient, a control plan has to combine preventive and curative action. Efficiency of
vaccination to control IMI is not yet clearly established and large scale controlled trials are still
needed on this topic. Therefore, we will not consider vaccination as an operating control tool in
the presentation.
4.3.1. Preventative actions
Since mastitis in dairy sheep results mainly from bacterial infections whose reservoir is
generally in the udder or teat and transmission between ewes is favoured by milking, the first
objective, both preventative and curative actions, is control of the reservoir, i.e. the infected
ewes.
The control of environmental sources consists in applying good housing recommendations
mainly to reduce staphylococcal pressure (density, air humidity…). This may be an important
feature during the lambing period characterized by a high concentration of animals.
Bacteriological transmission during milking is a key point for control actions. Thus the
milking machine must be cleaned and controlled regularly (once a year). The liners must be
replaced every year for rubber ones and every two years for silicone ones. The milking technique
must avoid teat impacts (and air inlets in general): brutal stripping, removal of the cluster without
cutting off the vacuum… The milking time must be adapted to avoid over or under-milking.
Teat-dipping or spraying is an efficient tool for reducing IMI incidence. But this technique is
antagonistic to a high milking throughput, specially for large flocks. Therefore, it can be
promoted, in a high prevalence situation, during a limited period, to deal with an unfavourable
situation with the aim of reducing IMI incidence.
To implement a milking order may also reduce the infection pressure, i.e. to first milk the
primiparous ewes, since they are less infected, and then the adult healthy ewes, followed by
groups of ewes of increasing IMI or SCC.
4.3.2. Curative action
The main curative action corresponds to the reduction of animals carrying infection can be
achieved in two ways :
1. culling of “infected” ewes
To reach this goal, the practical question is how to select the ewes to be culled?
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