Fig. 2.
Changes in G:F of nursery pigs at 7 to 11 kg BW by daily whey permeate intake (DWI) using a broken-line analysis (a one-slope model). Daily whey permeate intake (g/d) was calculated based on supplemental levels of whey permeate and average daily feed intake. The breakpoint for G:F of pigs weaned at 21 d of age was 87.9 g/d DWI when their G:F was 0.79 (P < 0.05). The breakpoint for G:F of pigs weaned at 25 d of age was 59.6 g/d DWI when their G:F was 0.85 (P < 0.05). The statistic models for feed efficiency of weaned pigs were G:F21 = 0.79 – 0.13 × 10− 2 × (87.9 – DWI) and G:F25 = 0.85 – 0.13 × 10− 2 × (59.6 – DWI); if DWI is ≥ breakpoint, then DWI = 0