Squirrels love tender new bamboo shoots.  We eat them too.  The shoots are high in sugar and the squirrels like the sweet taste.  The most effective way to save bamboo shoots from squirrels is to erect a physical barrier to the new shoots.  This will also discourage other rodents, like voles and mice.  You can make a barrier out of 2-foot lengths of pvc pipe or cylinders of ½” wire mesh (hardware cloth) also about 2 feet long.  Secure the cylinders in the soil, twisting them into the soil and using a stake driven into the soil for support if necessary.  When the bamboo shoots are 18-24 inches, they won’t be as tempting for the squirrels.  The “bamboo cages” can be removed, but keep an eye on them and put the barriers back if the squirrels start attacking them again.   This article has additional information,  Squirrels Chewing Moso Shoots  https://www.houzz.com/discussions/1735638/squirrels-chewing-moso-shoots.