Estimate frame score from hip height and age using Beef Improvement Federation–style quadratic equations for bulls or heifers.
Use this when you have a hip-height measurement (inches over the hooks) and the animal’s age in days, and you want a 1–9 style frame score for selection or sale descriptions.
Typical measurement window is about 5–21 months. Steers are often approximated with the bull equation — note that on the page.
BIF-published quadratic forms (hip height Ht in inches, Age in days):
Bulls: FS = −11.548 + 0.4878·Ht − 0.0289·Age + 0.00001947·Age² + 0.0000334·Ht·Age
Heifers: FS = −11.7086 + 0.4723·Ht − 0.0239·Age + 0.0000146·Age² + 0.0000759·Ht·Age
Measure height straight over the hooks. Age in months × 30.4 ≈ days for a quick convert.
Bull, hip height 48 in, age 365 days:
FS ≈ −11.548 + 0.4878×48 − 0.0289×365 + 0.00001947×365² + 0.0000334×48×365 ≈ 5.5 (rounded to one decimal).
Assumptions: equations follow common BIF hip-height forms; animal is standing square on a level surface.
Limits: outside ~150–640 days results are extrapolations. Breed standards and sale catalogs may round or table-lookup differently.
Responsibility: frame score is descriptive — not a substitute for EPDs or veterinary exam.
Directly over the hooks (hip bones), perpendicular to the ground, in inches.
Enter months in the helper field to fill days (months × 30.4). Precise Julian age is better when available.
Many programs approximate steers with the bull equation. Note that on any report you share.