Residents of Kogi were on Thursday advised to shun cow meat for at least one week.
The government gave the advice after 20 cows died mysteriously in Lokoja.
The state government says there is the possibility that the cows ingested poisonous substances while grazing.
Director of Veterinary Services, Kogi Ministry of Agriculture, Dr Salau Tarawa, gave the advice at a news conference.
He said beef from some of the cows were already in Lokoja markets, but had been recalled.
He said some of the cows had already been taken to markets in Osara in Adavi Local Government Area; to Ajaokuta, to Obajana, to Kotonkarfe and to Kakanda for sale to members of the public.
He said the ministry was collaborating with security agencies to bring the herders to question.
Speaking on the development, Head, Agro Rangers Unit Kogi State Command of the Nigeria Security and Civil Defence Corps (NSCDC), Bayode Emmanuel, said the cows were discovered in Lokoja.
“The cows emerged from the back of the state’s Secretariat complex where they had gone to graze. All of a sudden, they started behaving funny, slumped and died within minutes.
“Upon interrogation, the herder said he was coming out with the cows after grazing when the incident happened,’’ he said.
Emmanuel assured that the NSCDC would investigate the development thoroughly to ascertain where the dead cows had grazed and also to prevent possible sale and consumption of the infected beef.
