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AgridianDairy KB

Calf growth (ADG)

Definition

Section titled “Definition”

Average daily gain (ADG) is the weight a calf gains per day between two weighings. For dairy heifers it is tracked in phases:

  • Preweaning: birth to weaning (about 56–60 days).
  • Post-weaning: weaning to about 4–6 months.
  • Growing heifer: through breeding to first calving.

Preweaning ADG reflects the milk or milk-replacer feeding level, starter intake, disease, and environment (cold or heat stress). Faster preweaning growth has been associated with more first-lactation milk, though the size of the effect varies between studies.

A common preweaning goal is to double birth weight by 60 days of age (Dairy Calf & Heifer Association benchmark, as listed by Cornell AHDC; doubling birth weight by weaning was also the program goal in Soberon et al. 2012). For a 90 lb (41 kg) Holstein calf that means about 90 lb gained in 60 days, or about 1.5 lb/day (0.68 kg/d). Herds that wean at 56 days need about 1.6 lb/day. The same benchmarks list 2.2 lb/day ADG at 61–120 days and 2.0 lb/day at 121–180 days.

Formula

Section titled “Formula”

Plain text:

ADG (lb/d) = (weight 2 − weight 1) / (date 2 − date 1, in days)


Preweaning ADG = (weaning weight − birth weight) / age at weaning (days)


Weight ratio at weaning = weaning weight / birth weight

LaTeX:

\mathrm{ADG} = \frac{W_2 - W_1}{t_2 - t_1}
\qquad
\mathrm{ADG}_{\text{preweaning}} = \frac{W_{\text{wean}} - W_{\text{birth}}}{\text{age}_{\text{wean}}}

Herd ADG is the mean (or median) of individual calf ADGs, over calves with both weights. Report how many calves had both.

How to pull it in DC305

Section titled “How to pull it in DC305”

DC305 has no standard calf weight items. Herds commonly add user-defined items for birth weight (e.g. BTHWT), weaning weight and weaning date, or record a weight event with the value in the remark. Names differ by herd; check the herd’s private dc305-vocab mapping.

LIST ID BDAT BTHWT WNWT WNDAT FOR LACT=0 BDAT>-120 WNWT>0
SUM BTHWT FOR LACT=0 BDAT>-90 BTHWT>0

WNWT and WNDAT are example names. Compute ADG on an export, or with a calculated user-defined item if the herd has one.

Weights from automated feeders, walk-over scales or calf-ranch software usually live outside DC305; join them on calf ID.

Weighing methods

Section titled “Weighing methods”
  • Scale: the reference. Calibrate and zero it regularly.
  • Heart-girth tape: estimates weight from chest circumference. Tapes are breed-specific. Error for an individual calf is often 5–10%, and higher for very young calves.
  • Wither or hip height: tracks skeletal growth, which a weight tape misses.
  • Birth weight by eye: unreliable; values cluster at round numbers.

Data-quality filtering

Section titled “Data-quality filtering”

Before averaging, drop implausible weights:

  • Birth weight outside a plausible range for the breed. For Holsteins, values below about 40 lb or above about 130 lb are almost certainly entry errors (kg entered as lb, a missing digit, an ID typed into the weight field).
  • Negative ADG, or preweaning ADG above about 4 lb/day.
  • Weaning weight on the wrong date (the weighing date should match the weaning date used for age).
  • Heaping: many identical round values (80, 85, 90) suggest estimated, not weighed, birth weights.

Report how many records were dropped and why.

Typical range

Section titled “Typical range”

Herd context: US Holstein heifer calves, hutches or group pens, on freestall or dry-lot dairies and calf ranches.

Measure Typical Goal
Holstein birth weight 80–100 lb (36–45 kg) —
Preweaning ADG, conventional feeding (~4 qt milk/d) 0.8–1.2 lb/d —
Preweaning ADG, enhanced feeding (6–8 qt/d) 1.5–2.0 lb/d ≥ 1.6 lb/d
Weight ÷ birth weight at 60 d 1.6–2.0 ≥ 2.0 (DCHA)
Post-weaning to breeding ADG 1.7–2.0 lb/d ≈ 1.8–2.0 lb/d

Jersey calves are lighter (birth weight about 55–65 lb) and need breed-specific goals.

Common mistakes

Section titled “Common mistakes”
  • Averaging over calves with only one weight, or mixing estimated and scale weights.
  • Not filtering entry errors. One 900 lb “birth weight” moves a herd mean noticeably.
  • Comparing ADG over different windows (birth to 49 d vs birth to 63 d) as if they were the same.
  • Using a dairy heart-girth tape on beef-cross calves, or a Holstein tape on Jerseys.
  • Forgetting survivorship. Calves that died or were sold before weaning have no weaning weight, so ADG only describes the calves that made it.
  • Ignoring weather. Cold-stressed calves need more energy for the same gain. Compare like seasons.
Section titled “Related”