Do you know we have Seven Mothers?

Yes, we have Seven Mother According to Vedic Scriptures Let us see who they are: 

ātma-mātā guroḥ patnī
brāhmaṇī rāja-patnikā
dhenur dhātrī tathā pṛthvī
saptaitā mātaraḥ smṛtāḥ

SYNONYMS
ātma-mātā—one’s own mother; guroḥ-patnī—the wife of the guru; brāhmaṇi—the wife of a brāhmaṇa; rāja-patnikā—the wife of a king; dhenuḥ—the cow; dhātrī—the nurse; tathā—thus; pṛthvī—the earth; sapta etā—these seven; mātaraḥ—mothers; smṛtāḥ—should be remembered as.

TRANSLATION
“One’s own mother, the wife of the guru, the wife of a brāhmaṇa, the wife of a king, the cow, the nurse, and the earth are known as the seven mothers of a man.”
(Cāṇakya Paṇḍita)

Шримад-Бхагаватам
By His Divine Grace A.C. Bhaktivedanta Swaim Prabhupada from Canto 1, Chapter 11, Text 28

Seven Mothers

praviṣṭas tu gṛhaṁ pitroḥ
pariṣvaktaḥ sva-mātṛbhiḥ
vavande śirasā sapta
devakī-pramukhā mudā

praviṣṭaḥ—after entering; tu—but; gṛham—houses; pitroḥ—of the father; pariṣvaktaḥ—embraced; sva-mātṛbhiḥ—by His own mothers; vavande—offered obeisances; śirasā—His head; sapta—seven; devakī—Devakī; pramukhā—headed by; mudā—gladly.

After entering the house of His father, He was embraced by the mothers present, and the Lord offered His obeisances unto them by placing His head at their feet. The mothers were headed by Devakī [His real mother].

It appears that Vasudeva, the father of Lord Kṛṣṇa, had completely separate residential quarters where he lived with his eighteen wives, out of whom Śrīmatī Devakī is the real mother of Lord Kṛṣṇa. But in spite of this, all other stepmothers were equally affectionate to Him, as will be evident from the following verse. Lord Kṛṣṇa also did not distinguish His real mother from His stepmothers, and He equally offered His obeisances unto all the wives of Vasudeva present on the occasion. According to scriptures also, there are seven mothers: (1) the real mother, (2) the wife of the spiritual master, (3) the wife of a brāhmaṇa, (4) the wife of the king, (5) the cow, (6) the nurse, and (7) the earth. All of them are mothers. Even by this injunction of the śāstras, the stepmother, who is the wife of the father, is also as good as the mother because the father is also one of the spiritual masters. Lord Kṛṣṇa, the Lord of the universe, plays the part of an ideal son just to teach others how to treat their stepmothers.

tāḥ putram aṅkam āropya
sneha-snuta-payodharāḥ
harṣa-vihvalitātmānaḥ
siṣicur netrajair jalaiḥ

tāḥ—all of them; putram—the son; aṅkam—the lap; āropya—having placed on; sneha-snuta—moistened by affection; payodharāḥ—breasts filled up; harṣa—delight; vihvalita-ātmānaḥ—overwhelmed by; siṣicuḥ—wet; netrajaiḥ—from the eyes; jalaiḥ—water.

The mothers, after embracing their son, sat Him on their laps. Due to pure affection, milk sprang from their breasts. They were overwhelmed with delight, and the tears from their eyes wetted the Lord.

When Lord Kṛṣṇa was at Vṛndāvana even the cows would become moistened by affection towards Him, and He would draw milk from the nipples of every affectionate living being, so what to speak of the stepmothers who were already as good as His own mother.

Srila Prabhupada : 

According to Vedic civilization, anyone who supplies milk from the body, she is mother. So cow is mother because we are drinking her milk. So from that point of view, one cannot kill cow.
If a boy wants to understand, “Who is my father?” the only authority is the mother. Vedic literature is considered to be the mother. She gives evidence that God or Lord Krishna is our father.

So now we know that we have seven mothers so let us celebrate this Mothers day by respecting and serving all this seven mothers. How can we serve and love all thsi seven mother is very simple . We can serve all this seven mother if we love our real father the creator of the whole cosmos Sri Krishna. Mother is embodiment of Real Love so if we want to give back her love then Learn to love Krishna by practicing Krishna consciousness bhakti yoga. Formula of Real Love is simple Love the Creator you will love whole creation. Happy Mothers Day 

Hare Krishna.