Police are investigating the "mindless" damage to the building in Skewen Park in Neath.
The council says it needs to save £35m and wants clubs to take on responsibility for the facilities.
BBC Sport meets Harriet Stevens after the bowler won two national outdoor titles while eight months pregnant
Wales is to host the 2019 World Bowls Atlantic Championships in May, bringing players from 20 nations to Cardiff and the Vale of Glamorgan.
Audio & Video
England's Nick Brett wows crowds at the World Indoor Bowls Championships in Great Yarmouth with a spectacular shot in the open pairs final.