In India, a land of Hindus, cows are worshiped across the nation. Any significance of it?
गाव: स्वर्गस्य सोपानं गाव: स्वर्गेपी पूजितः । गाव: कामदुहो देव्यो:नांन्यत किंचित परं स्मृतं ।।
Cows are the path to heaven, they are worshipable even in heaven. Cows grant a desirable objects, therefore there is nothing superior to the cows.
(गाव:) = cow
ब्रह्म सूर्यसमं ज्योतिर्ध्य: समुद्र: समं सर:। इंद्र: पृथीव्य:वर्षीययाँ गोस्तु मात्रा न विद्यते ।।
Brahma Vidya, (ब्रह्म विद्या) which grants supreme bliss is compared to the Sun.Earth to Indra deva but the cow, which does unlimited welfare to hunamy, cannot be compared to anything cow is without any comparison. Indeed there is no other being like a cow, which does welfare to human beings.
Yajurved (यजुर्वेद) 23.48
प्रजावतीः सुयवसे रुशन्तीः शुध्द अपः सुप्रपाणे पिबन्तीः। मा वस्तेन ईशत माघशंसः परि वो रुद्रस्य हेतिर्वृणक्तु।। (अथर्व.-7.75.1)
In Athervaveda (अथर्ववेद) there are verses which states that the cow are be protected and. It is considered a sin to kill a cow
In Hinduism We Respect, Honour and Adore the cow and Calf . In Hinduism or Sanatan Dharma (सनातन धर्म) We see Cow as a Godess and as Mother (माँ). Therefore, the cow is considered a sacred animal, as she sustains us and our babies , elderly people etc with her milk.
Since from ages Cow dung is used as fuel in our houses as it is high in methane, and can generate heat and electricity. Village houses are plastered with a mud/cow dung mixture, which insulates the walls and floors from extreme hot and cold temperatures. dung is also rich in minerals, and makes an excellent fertilize in our farms.
The surabhi cow (सुरभि गाय) descended from the spiritual worlds and manifested herself in the heavenly spheres from the aroma of celestial nectar for the benefit of all created beings.
So cow is the most Holy Animal in Sanatan Dharma (सनातन धर्म) Or Hinduism , She contains all 33 Crore Gods in her.
Cows are the only animals that gives milk to humanity. As a baby takes birth only a mother can feed it. Comparing this two, we can say cow is mother who is sacrificing milk which is prerogative of its own child for humanity.Many medicines are made from the urine of cows.
There is a verse
gavo me vyagrato santu gavo me santu prushtata, gavo me hridaye santu gavam madhye vasamyaham
When Lord Krishna says cows contain all deities in them and in the heart of cow saintly properties reside. Lord Krishna narrates himself as he is Kamdhenu among cows in Goloka.(Land of cows) who fulfills every desire.
Thus cows are considered very important and pious animal when Goddess Gayatri became cow and stood behind Lord Dattatreya and in the same fashion she supported Lord Krishna too. This is the reason why cows are there in the pictures of Lord Dattatreya and Lord Krishna.
Goddess Umiyamata, incarnation of Mother Parvati also has cow as her vehicle. Following cows are placid and calm, they are also great virtuous donors. As per astrology feeding cow is considered virtuous acts that removes any kind of trouble. Pacifying cows also gives peace in life. Therefore, cow is worshiped as a mother.