Heifer Weight Calculator
when will she reach breeding weight?
Enter a heifer's date of birth, breed and a few dated weights. See her daily gain, how she compares with the breed's growth curve, and the date she should reach breeding or pre-calving weight.
Heifer Growth
The example values below are a Holstein heifer. Replace them with yours.
Prediction
Growing Heifers to the Right Weight
Breeding by weight, not age, gives heifers a better start.
A common guideline is to breed dairy heifers at about 55–60% of their mature cow weight and to have them at about 85% before first calving. For a Holstein with a 650 kg mature weight, that is about 360 kg at breeding. Smaller breeds have lighter targets, so the tool scales the targets and the growth curve to the breed's mature weight.
The prediction compares the heifer's daily gain from your weighings with the expected gain for her age, then applies the same ratio to the coming growth phases. A heifer growing at less than 60% of the expected rate gets a warning instead of a date: find out why before relying on a prediction.
How to use this calculator
- Enter the heifer's date of birth and choose her breed, or "Other breed" with a typical mature cow weight.
- Enter her birth weight if you know it. Leave it blank to use the breed's typical birth weight.
- Choose the target: breeding weight, pre-calving weight or a custom weight of your own.
- Replace the example weighings with hers: the date and weight of each, up to 10. Use Add weighing for more rows.
- Read the predicted date, then check the chart to see how her weighings sit against the breed curve.
Reading the result
With two or more weighings, the daily gain is the trend through all of them, so one odd weighing has less effect. With one weighing, it is the gain since birth. The date under Reaches target assumes she keeps growing at the same pace compared with the curve. On the chart, blue dots above the grey dashed curve mean she is ahead for her age; dots below it mean she is behind. If the date is later than you planned for breeding, look at her ration with your nutritionist, and at health and parasites with your vet.
Common questions
My breed is not in the list. What do I do?
Choose "Other breed" and enter the weight of a typical mature cow in your herd. The targets and curve scale to that weight.
How often should I weigh heifers?
Every 1–3 months is enough to follow growth. Use a scale or weigh tape, at the same time of day, before feeding.
At what age should a heifer reach breeding weight?
Holstein heifers on a good growth plan often reach breeding weight at about 13–15 months and calve at 22–24 months. Other breeds, and buffaloes, may get there at quite different ages. Go by weight and size rather than age alone, and agree the breeding plan with your vet.
Why does it say daily gain could not be worked out?
The weighings do not show any gain: for example, two weighings on the same date, or a later weight that is lower than an earlier one. Check the dates and weights, or add another weighing a few weeks later.
Can a heifer grow too fast?
Yes. Heifers that get too fat, especially before puberty, can lay down fat in the udder and may give less milk later. Aim for steady growth close to the curve rather than as fast as possible, and check her body condition with your nutritionist.
Decision support only. Not a substitute for your veterinarian.