Recent trial work carried out by the Agri-Food and Biosciences Institute (AFBI) has highlighted the benefits of selective dry cow therapy as a mainstream dairy management tool.

Standard antibiotic-based dry cow therapy involves the infusion of a long-acting antibiotic into each teat at drying off.

Traditionally, this approach has been to taken to treat existing infections and to prevent new infections.

But, up to this point, the technique has comprised a ‘blanket approach’, with all the cows within a herd being treated in an equal manner.

However, as udder health has improved, and concerns about antibiotic usage have increased, research scientists at AFBI have fundamentally challenged this approach.

Selective dry cow therapy

Selective dry cow therapy involves making a decision for each cow as to whether antibiotic treatment is necessary.

On that basis, antibiotic treatment is restricted to cows considered ‘high risk’. ‘Low risk’ cows receive teat-sealant only.

The selection criteria normally put in place includes previous mastitis history and somatic cell count (SCC) history.

So the fundamental question becomes – does drying off ‘low risk’ cows without antibiotics negatively impact on cow performance or udder health?

AFBI trial

Courtesy of a two-year experiment using the AFBI herd, cows were catergorised as being either high risk or low risk.

High risk cows were identified as those having an SCC of greater than 200,000/ml during any of the last three monthly milk recordings prior to drying off, or had one or more cases of mastitis during the three-month period prior to dry-off.

These animals received a standard dry cow treatment.

Low risk cows were those with an SCC of less 200,000/ml during the three milk recordings prior to drying-off and had recorded no cases of mastitis during the three months prior to dry-off.

These cows were allocated one of two treatments: either a conventional dry cow treatment or a selective dry cow treatment, focusing on the use of a teat sealant only.

The conclusions arrived at confirm that in the case of ‘low risk’ cows dried-off without antibiotics, no negative impact was observed on subsequent cow performance or udder health.

But the work has also highlighted the absolute need for two issues to be fundamentally addressed, if selective dry cow therapy is to have successful, on-farm outcomes.

These are the need to have accurate SCC information on each cow within a herd and, in addition, the priority of implementing the highest standards of hygiene when it comes to the placement of teat seals.