There are so many references to Surabhi the cow in the Vedas, especially the Srimad Bhagavatam.
The Lord said that the original mother of all cows is Surabhi, who lives in Goloka.

She is the source of all cows. It was Surabhi who first appeared in Vrndavan, from Goloka. 

Who were the Pandavas? 

They were 5 brothers who were devoted to Krishna and eventually they went into battle against their own cousins, the Kauravas.   But before the battle began, Krishna spoke with one of the Pandavas, Arjuna, the great song, The Bhagavad-gita.

In the Mahabharata, there is a story about the Pandavas that includes cows. 

Who was King Dileep?

He was a valiant king of the Ikshvaku dynasty of Ayodhya, and an ancestor of Lord Rama.  
Here is a rather long story about King Dileep but absolutely fascinating!

The Ramayana was written by the sage Valmiki and is the beloved and epic pastimes of Lord Rama. 

The sage Vasistha describes: “If one carefully studies the pastimes of Sri Rama, one can find that the cows had a special role to play in them.” 

Gomati-vidya means "the science of the cow," and refers to Vedic knowledge regarding the cow's spiritual, medicinal, and ecological significance.

This science is found in a variety of Vedic texts. 
Here are just 2 texts from Part 3 of a Purana:

Originally, Srila Vyasadeva composed one Veda, and then he divided it into 4 divisions: Rg, Yajur, Sama and Atharva.  

A 5th Veda was formed which consists of the Puranas, the Mahabharata, Samhitas and so on. 

Throughout the Vedas, the cow is described as an ocean of auspiciousness, and many prayers have been composed for her.

Here are 3 prayers from the Rg Veda: 

Ayurveda is a holistic medical system contained in the Atharva Veda. In Ayurveda the products of the cow are important for maintaining our good health. Let us consider in this episode: cow milk, yogurt, butter, and ghee.

Welcome to this short 8 episode Podcast about the glories of the cow. The Srimad Bhagavatam describes so many pastimes of the Supreme Lord, Sri Krishna, and His love for the cows and calves.  SB: 10.14.12-13 describes:

“When the cows and calves would go to a far away forest and Krishna would affectionately yet gravely call them by their names, they would become completely overwhelmed by love for Krishna. Milk would begin to fall from their milk bags and they would come running to Krishna.