624. Udder infections in the ‘dry period’: II. The effect of withdrawing secretion from the dry udder on the incidence of infection

Abstract

1. An experiment was carried out with seventy-five dry cows to study the effect of taking samples of udder secretion for bacteriological examination on the incidence of new infection in the early dry period. The incidence of new infection in two quarters of each cow, sampled at weekly intervals after drying off, was compared with that in the remaining two quarters sampled in the fourth and fifth week of the dry period.2. No difference in the new infection rates was found between the quarters that were sampled early in the dry period and those that were not.3. Significantly fewer (P <0·05) staphylococcus infections occurred in quarters sampled in the early dry period compared with those sampled at a later stage.4. About half of all the new infections persisted until the next lactation.5. It was concluded that if natural sealing of the teat orifice or teat sinus takes place it is of minor importance in preventing infection in the early dry period.