Peak lactation and natural decline through the cycle
A dairy cow begins lactating after calving (birth). Milk yield rises steeply in the first 2-4 weeks, peaks at 6-8 weeks post-partum, then declines gradually through a 305-day lactation cycle (industry standard before the cow is dried off for rest).
Peak milk yield varies by breed and nutrition: a high-producing Holstein peaks at 80-100 pounds per day; a Guernsey peaks at 50-60 pounds. Maintaining high-quality nutrition (high energy and protein feed) sustains production longer but cannot prevent the natural decline.
Nutrition management during lactation stages
The first 2-4 weeks (transition period) are critical. Cows mobilize body tissue to support milk production, creating metabolic stress. Poor transition management increases mastitis, ketosis, and fertility problems. Fresh cows need high-energy, high-fiber feed and constant water.
Mid-lactation (8-16 weeks) is stable. Cows eat to maintain milk while rebuilding body condition. Late lactation (16-40 weeks) sees declining yield but improving body condition as energy intake exceeds milk energy output. Managing dry-off (stopping milking to allow udder rest) requires reducing intake and ensuring colostrum (immunity proteins) for the next calf.
Herd planning and economic rhythm
Dairy farms stagger calving to spread lactation curves across the year, providing even milk supply for processing and stable labor demand. Cows are dried off (not milked) 60 days before the next expected calving, allowing mammary tissue recovery.
Economics depend on milk price and feed cost. A cow that peaks at 100 pounds daily, declines to 60 pounds by week 20, and is dried at 40 pounds (day 305) has produced 17,000-20,000 pounds per lactation. Managing nutrition to sustain that plateau as long as possible maximizes revenue per cow.