FAQs Herd Introductions

Guidance for veterinary practitioners, government animal health staff and dairy herd advisers on the Dairy Score.

What happens to the base Score of the herd when adult cattle with a lower Score are introduced?

The base Score of the herd is lowered to the lowest Score adult animal.  Because individual adult animals keep their Score for life, there is no effect on the Scores of either the introduced adult cattle or the adult cattle already in the herd.

What happens to the base Score of a herd when adult cattle with a higher Score are introduced?

No change to the base Score of the herd.

How do leased and introduced bulls affect the base Score of a herd?

The situation with respect to bull introductions is considered different to that of introduced female cattle and there is no chnge in the base Score of a herd. This is due to the generally lower risk conditions associated with their introduction.


Farmers need to adopt sound risk management when bulls are to be introduced to ensure there is no increased risk of BJD. Factors which reduce the risk from the introduction of bulls are:


  • Bulls are kept separate from calving cows and from animals less than 12 months of age
  • Beef bulls have lower risk as BJD prevalence is much lower in beef cattle
  • Young bulls (typically 2‐4 years), even if infected, are unlikely to excrete organisms
  • Bulls, if leased, spend only short time on the farm
  • Small numbers of bulls introduced
  • Bulls are introduced from CattleMAP herds