Ivan Antonovich Mertsalov was born into the family of Major Anton Lavrentievich and Vera Nazarovna Mertsalov. He had a sister, Anna, and their family owned the village of Pankovka, where they lived. No images of Ivan Antonovich have survived.

He served in the cavalry and retired with the rank of lieutenant. After that, he dedicated his life to agriculture. Contemporaries noted that I. A. Mertsalov was a "subtle connoisseur of fine wool sheep breeding" and he can be called the "father of fine wool sheep breeding in Eastern Ukraine."

Mertsalov is considered one of the founders of animal science in Ukraine. After his death, his works were published at the printing house of Kharkiv University: "Notes on the Breeding, Keeping, and Improvement of Spanish Sheep" and "Notes on the Sorting of Spanish Sheep and the Quality of the Wool They Produce."

Ivan Antonovich developed a new Ukrainian fine wool breed of sheep called "Russian Infando," which met the climatic conditions and requirements of the wool market. Sheep of this breed weighed 50-60 kilograms, produced an average of 5 kilograms of wool, were resilient, and tolerated frost well. Mertsalov wrote that over time these sheep should receive a new type of fine wool in Russia. Ivan Antonovich dedicated 27 years of his life to this endeavor.