Vet Cadets: Saving Itsy Bitsy (Book 3) by Rebecca Johnson

Abbey, Hannah and Talika are new recruits at Willowvale boarding school's Vet Cadets program. And what a year it is turning out to be! Henrietta, the school pig, has had a very large litter of piglets. But something is wrong with Itsy Bitsy, the smallest piglet, and the girls must work together to fight for her life.

There's also the mystery of some stolen cattle to solve - it seems that saving lives and crime fighting through science are all just part of a normal school day for these clever Vet Cadets.