Neutering a boar will alter his behaviour FALSE The only things that neutering a male will do are preventing him from impregnating females and slightly lessening the risk of impaction.
They are not the same as dogs, cats and several other species, neutering has little effect on the behaviour of a male. If two males fight, they will still fight post-neuter.
See
http://www.cavyspirit.com/neutering.htm for more information.