This is usually taken a little more seriously than a mere "domestic"
Not strictly true.

An officer, having been assaulted, will always put in a complaint/statement, and CPS will therefore be more likely to authorise charge and see it through to court, if necessary.

Whilst a victim of "domestic" will invariably have been assaulted 10-20 times before even ringing the police, and then may need a further 10 assaults before being willing to see a prosecution through to court. Without support from the victim (usually the only witness) the CPS is unlikely to even authorise the charge as a prosecution is unlikely.

As a side line - did you know that, in the course of their duties and according to recent legislation, an officer is not treated like a member of the public for many offences. They are expected to withstand far more in relation to physical and verbal abuse before being 'allowed' to arrest.
( Another_tragic_case wished he hadn't eaten all the cake, Thu 12 May 2011, 10:02, Reply)