The effect of feeding barley on diet nutrient digestibility and growth performance of starter pigs

• High or low quality barley grain replaced 650 g wheat grain/kg in diets for weaned pigs starting 1 week post-weaning.
• Dietary inclusion of barley grain to replace 650 g wheat/kg reduced energy digestibility but not growth performance of weaned pigs.
• Pigs fed low quality barley diets had greater feed intake and growth performance than pigs fed wheat diet.
• A correction for NE value is not needed for pigs fed low quality barley diet to main growth performance.

Wheat and barley are feed grains used as dietary sources of energy for swine in western Canada, Australia and northern Europe. Inclusion of high quality (HQ) barley grain in starter pig diets is limited due to its greater fibre content and lower net energy (NE) value than wheat. Low quality (LQ) barley due to adverse agronomic conditions is also available, but its feed value for young pigs is unknown. To explore, 280 starter pigs (initial body weight: 8.65 ± 0.87 kg) were fed pelleted diets including HQ or LQ barley (with or without balancing for NE value) to replace 650 g wheat/kg for 3 weeks starting 1 week post-weaning. Five diets were formulated as [MJ NE/kg; g standardised ileal digestible (SID) lysine/MJ NE]: 1) wheat (10.0, 1.07); 2) HQ barley (10.0, 1.06); 3) LQ barley without NE correction (9.76, 1.09); 4) LQ barley with NE correction (10.0, 1.06); and 5) LQ barley with low NE value (9.42, 1.12). The apparent total tract digestibility coefficient (CATTD) of gross energy (GE) was greater (P < 0.05) for the wheat diet than for barley diets. The CATTD of GE was lower (P < 0.05) for the HQ barley diet than for LQ barley diets and greater (P < 0.05) for the LQ low NE barley diet than the LQ barley diet without NE correction. The digestible energy (DE) and predicted diet NE value were greater (P < 0.05) for the wheat diet than barley diets except for the LQ barley diet with NE correction. These energy values were lower (P < 0.05) for the HQ barley diet than for LQ barley diets and greater (P < 0.05) for the LQ barley diet with NE correction than LQ barley diets without NE correction or low NE. For day 1–21, average daily feed intake (ADFI), average daily gain (ADG) and feed efficiency (G:F) of the wheat diet did not differ from that of the HQ barley diet but was lower (P < 0.05) than those of LQ barley diets. The ADG of the HQ barley diet did not differ from LQ barley diets. The NE correction did not affect ADFI, ADG and G:F of LQ barley diets. In conclusion, despite lower nutrient digestibility and energy value, LQ or HQ barley can fully replace wheat grain in diets for starter pigs and achieve equivalent or better growth performance.