As many as 21 cows have died of food poisoning since April 27 at a 'gowshala' in Andhra Pradesh's Vijayawada city, police said.Nineteen cows had died till Sunday while two cows died on Monday.More than 200 cows fell ill on April 27 at the gowshala run by Gow Samrakshana Sangham after they were allegedly given cattle feed after its expiry date, police said.The owner of an industry which donated the cattle feed has been arrested. Police also booked 29 members of the gowshala for negligence.The action was initiated after police scanned the CCTV footage and identified the people who fed the cows on the night of April 27.Most cows showed signs of recovery but some animals are still in critical condition.Veterinary department officials said the cows could have died of Tympanites (gaseous indigestion) due to consumption of feed that is not suitable to them.The death of the cows triggered outrage. People are demanding stringent action against those responsible.The Andhra Pradesh government has ordered an inquiry by the Collector of Krishna district.