Biosecurity refers to practices used to prevent both the introduction and of the spread of diseases within a farm. Diseases can enter farms either directly through infected cattle or indirectly through contaminated equipment or footwear.
More information about biosecurity on beef farms can be found in Chapter 40 of the Teagasc Beef Manual Biosecurity.(pdf)
Habituation to a new environment (pdf) of the Teagasc Calf Rearing Manual provides details of avoiding disease introduction with bought in calves. This can also be viewed through the following video, Calf Rearing- Calf transport and procurement.