The Bull standing with its four limbs is considered to be symbolic of dharma. The four limbs represent the four Yugas – Sathya Yuga, Tretha Yuga, Dwaapara Yuga and Kali Yuga.
It is said the Bull standing firmly with four legs conveys dharma is followed in its complete sense with no violation absolutely.
This is witnessed in Satya Yuga
In Tretha Yuga it is seemed to be three legs firm and one leg crippled showing 1/4th violations of dharma creeping in.
In Dwaapara Yuga two legs firm and two legs crippled meaning 1/2 violations of dharma making its way
In Kali Yuga only one leg firm and 3 crippled making 3/4th violations dominating the earth. The author Sri Narayanacharya, in his work, ‘Sri Raghavendra Vijaya; writes that the evil Kali infusing strife, discord, quarrel and hatred starts panicking immediately after seeing child Venkatanatha crawling. The child crawling with its two legs and two hands appears like the bull representing dharma to the evil kali he worries satya yuga has commenced and it is the time for him to exit. This affirms the birth of this child would create a new era up-folding all the virtues of dharma and the evil finding no place.
Much to his disappointment, the evil Kali witnesses the child evolving to become Sri Raghavendra Tirtharu propagating Madhva philosophy, making the Hindu scriptures easy to understand showing unlimited compassion, displaying extreme Vyragya, removing the ignorance, instilling Bhakti and granting with generosity. He clearly stated Lord Hari is supreme.