Police in Homa Bay County are investigating the killing of 31 head of cattle and injury of 28 others.
More than 12 farmers from several villages in Kayanja and Waondo in Mbita Sub-county were affected.
They woke up on Tuesday to the sight of carcasses and injured cows, most with deep stab wounds in their bellies.
The farmers condemned the incident, terming it a serious economic loss, since some of the cows gave them milk, while others were useful during ploughing.
George Nyariga, a resident of Kamolo village and one of those whose cows were stabbed, called for quick investigation into the incident.
“One of my cows died while the other has a serious cut in the belly. I am not sure it is going to survive because of its deteriorating health,” said Mr Nyariga.
Kanyanja Assistant Chief Moses Sirawa said the motive of the attackers was unknown.
The assailants did not steal anything from the homes.
Mbita Sub-county Police Commander Stanley Atavachi said investigation was ongoing.
“We don’t know the motive of the criminals but we will ensure they are brought to book,” said Mr Atavachi.
Homa Bay County Commissioner Moses Lilan said a public baraza would be called to discuss the matter.
He said security agencies had crucial leads on suspects.