Drying off is often a significant decision-making time for herd management, whether the herd is  seasonal, split, or year –round calving. It is at this point that decisions are often made about a cow’s future in the herd, and one of the considerations will be her cell count history for the lactation that is ending.

If a cow has a history of any high cell count (greater than 250,000) during the lactation, decisions must be made about the cow in terms of dry period therapy or possible culling.

We can refer to Countdown Downunder Farm Guideline 15.2 where it tells us to “Consider culling cows with high cell counts in two consecutive lactations, despite treatment with Dry Cow Treatment in the dry period between.”

A high cell count in two consecutive lactations, despite Dry Cow Treatment at the intervening drying off, indicates that the cow may have an infection that has persisted despite treatment, and is therefore likely to be refractory to further treatment.

Cows such as these, that are unlikely to cure, should be considered for culling. Some of the factors to consider in this decision are –

·    whether the cow has also had one or more clinical cases during the lactation;

·    the impact of that cow on the BMCC and consequently on the milk payment;

·    the risk of mastitis spreading to other cows in the herd; and

·    the cost of replacement cows.

The final decision of whether to cull a cow or not will also depend on other factors, such as the production of the individual cow, her genetic merit, her pregnancy status and the availability of sufficient replacements.

At the very least, if she is to remain in the herd, she is a candidate for antibiotic dry cow therapy at drying off, and her cell count should be closely monitored in the next lactation.