Hi, Since your baby has shown symptoms like hard stool,cramps,gas trouble after starting baby formula. To confirm if he is lactose intolerant stool examination is required to see for presence of reducing substances. He may require dulcolax suppository,to be put directly through anus into the anal canal or inside by himself or by expert paramedic. It will stimulate bowels after few minutes and defecation will be possible. To avoid this recurrences, always take high fiber diet means salad along with any meal. Continue with probiotic as well. I suggest you to add zinc after consulting your doctor. Also give him boiled pulses water,coconut water.boiled rice water. If symptoms persist get him re evaluated by paediatrician for further management.