In War Horse does Albert sign up to be in the war?

Albert signs up for the Veterinary Corps because he is to young to join the British forces.

‘You’re not on about your Joey again?’ The head that came with the voice leant over the stabledoor. ‘Won’t you never give it up, Berty? I’ve told you before if I’ve told you a thousand times. They say there’s near half a million ruddy horses out here and you joined the Veterinary Corps just on the off-chance you might come across him.’