A 200 cow dairy farm in Bulgaria (Borjana Zlatanova, Jeljazno) feeding a high maize ration (30+% starch) used Optipartum-C+ for 30 days.

After a change in dung consistency after 10 days, he soon noticed an extra 2 litres (29 up to 31 litres) 21 days into using OC+.

Comparing performance at similar days in milk across the herd, before and after using OC+ showed that the improvement in yield was achieved by improving the yield across all stages of lactation.

Bulgarian milk yield data