Replacement heifers
Heifer target breeding weight calculator
Set the target now and know the gain per day your heifers need before the bulls go in.
Target breeding weight = mature cow weight × target share. The classic target is about 65% of mature weight (University of Wisconsin Extension). With 1,200 lb cows the target is 780 lb. A heifer that weighs 600 lb with 150 days to go has to gain 180 lb, or 1.20 lb per day.
Example numbers. Change them to your own.
Choosing the inputs
- Mature cow weight. Use the average weight of your own mature cows, not a breed average.
- Target share. The classic target is about 65% of mature weight. University of Wisconsin Extension notes newer research where lighter targets, about 50 to 57%, did not hurt reproduction in well-managed heifers.
- Days until breeding. Heifers should calve at about two years old, which means breeding at about 14 to 15 months.
- Weigh again midway. Check the real gain with the average daily gain calculator and adjust the ration while there is still time.
How much should a heifer weigh at breeding?
The classic target is about 65% of her expected mature weight. University of Wisconsin Extension notes newer research suggesting lighter targets, around 50 to 57%, can work when heifers are well managed.
How do I calculate target breeding weight?
Multiply the average weight of your mature cows by the target share. With 1,200 lb cows and a 65% target, 1,200 × 0.65 = 780 lb.
How much should replacement heifers gain per day?
Subtract today’s weight from the target and divide by the days until breeding. A 600 lb heifer with a 780 lb target and 150 days to go needs 1.20 lb per day.