When the 13th year of Vanvas was ending, the kauravas were pretty anxious to find out the Pandavas.
If Pandavas were found before the end of Agyaatvaas then they had to go in 12 year Vanvas again as per rule of the agreement.
Duryodhan had hints that they might be hidden in Matsya Capital Virat.
The dairy and horse power of Virat hinted the presence of Nakul and Sahdev.
Administrative excellence pointed towards the presence of Yuddhisthir in the board of advisors of king Virat.
The murder of Keechak was a strong signal of presence of Bheem in the royal palace of Virat.
But kauravas had to be sure.
They had to bring the Pandavas out if their hidden identity.
Then Kauravas decided to steal the cows of Matsya Desh.
They new that Righteous Yuddhisthir will never allow the cows if his host king to be stolen.
He will send his brothers to stop the theft. And this worked out.
Though Kauravas failed to recognise Pandavas in time but that's another story.
This incident proves that We had been respecting cows and considered even stealing them as severe crime even 7500 years ago.
How can we even tolerate the beef eaters in our country?