A new calf feed supplement could be the good news farmers have been waiting for.

Economic research firm BERL and Massey University have found a supplement called Queen of Calves could save the farming industry $340 million a year if 10 percent of farmers adopt its use.

BERL director Kel Sanderson says the supplement has amino acids and proteins that ensure the calves grow more flesh and ultimately become stronger cows.

"Instead of raising a whole lot of cows, taking them up to the first or second lactation and then them dropping out of the race, these ones keep going on through.

"So you can actually on the same area of land, the same amount of grass, you can produce a lot more milk."

Sanderson says the seven-year ongoing study looked at the output of cows which had been given the supplement.

"They gave an average of 30 kilos of milk solids more than the cows that hadn't had this treatment, and that's $6 a kilo.

"That's $180 for every cow in your herd."