Abstract Weighing cattle under different feeding conditions can alter gut fill, resulting in variation in body weight (BW) and influencing estimation of growth rates. This study examined how two weighing protocols affect the precision of predicted ADG. Crossbred steers (n = 176; initial BW = 368 ± 19 kg) were limit-fed a diet of 50% hay and 50% wet corn gluten feed (Sweet Bran, Cargill) DM basis (LFD) at 2% of BW on a DM basis for 5 d and weighed for 3 consecutive days before trial initiation. Steers were blocked by weight (light and heavy), then stratified within block and assigned randomly to pen (n = 8 per block) and pen was assigned randomly to one of two treatments: limit weight (LW) or shrink weight (SW). Cattle in the LW treatment were fed LFD at 2% BW for 5 d and weighed on d13 and 14. Cattle in SW were fed the same diet but ad-libitum and were shrunk for 16 h on d14, after which a single weight was obtained. Then both LW and SW cattle were fed ad-libitum a diet of 50% wheat straw, 27% grass hay, 20% Sweet Bran, and 3% MDGS (DM basis) starting on d14. Feed was removed from SW cattle on day 70 for a 16 h shrink and weighed. Cattle in SW were fed ad-libitum on d71 and on d72 all cattle were fed the LFD at 2% of BW and weighed on d82 and 83. Residual standard deviations (RSD) were used to assess within-treatment variability in BW. When the limit fed ADG of LW was compared to the shrunk ADG of SW there was no difference (P = 0.08) in RSD. However, estimated ADG was greater (P = 0.01) for SW steers (0.90 kg/d) than LW (0.78 kg/d), indicating that weighing protocol influenced growth rate estimation. However, the limit fed end BW for both treatments did not differ (P = 0.33). It is worth noting that the SW had more gut-fill when shrunk (end BW 428 kg) than when limit fed (end BW 419 kg). These results demonstrate that while both shrink and limit-feeding protocols had similar within-treatment variability, they are not interchangeable for estimating growth. There were also differences in gut fill between the initial and final shrunk weights of SW. Specifically, the difference between shrunk and limit-fed BW of SW was only 3.6 kg (0.97% of BW) at the start of the trial, but 10.9 kg (2.61% of BW) at the end. Therefore, inconsistent diet conditions between shrunk weights may bias accuracy of growth estimates. Limit-feeding a standardized diet resulted in similar precision to shrunk weights. However, accuracy is dependent on ability to project gain while fed the standardized diet.
Lara et al. (2026) studied this question.