Strategy to blend leftover finisher feed to nursery pigs in a wean-to-finish production system

In wean-to-finish pig production, leftover finisher feed from the previous group is commonly blended with nursery diets as weanling pigs enter the facility. Two experiments were conducted to evaluate feeding the last finisher diet to nursery pigs. The timing (phase) and dose were evaluated. Each experiment used 1,260 pigs from two commercial research rooms with 21 pigs per pen and 30 pens per room (15 pens per treatment). Pigs were fed commercial nursery diets in a five-phase feeding program, and phase changes were based on a feed budget. In experiment 1, pens of pigs (initially 5.83 kg) were blocked by body weight, gender, and room and allotted to one of four treatments. Treatments included standard nursery diets throughout (control) or standard diets with 2.5 kg/pig of the last finisher feed blended at the beginning of phase 2, 3, or 4. Growth responses during the intermediate periods were promptly decreased (P < 0.05) once the finisher feed was introduced regardless of phase in which it was blended. However, during the overall nursery period, blending the finisher diet into phase 2 decreased (P < 0.05) average daily gain (ADG) and average daily feed intake (ADFI), but did not affect gain:feed ratio (G:F), compared with control pigs or those that had blended diet in phase 4 with blending of phase 3 diet intermediate. In experiment 2, weaned pigs were fed common phase 1 and 2 diets before the start of the experiment. At the beginning of phase 3, pens of pigs (initially 10.6 kg) were blocked by body weight and room and allotted to one of four treatments. Treatments consisted of a dose-titration of blending increasing amounts of finisher feed (0, 1.25, 2.50, and 3.75 kg/pig) into the phase 3 nursery diet. Overall, blending increasing amounts of the last finisher feed with phase 3 nursery diet decreased ADG (linear, P = 0.050) and tended to decrease (linear, P < 0.07) ADFI and final body weight. However, there was no evidence for difference in overall G:F. In conclusion, blending finisher feed into the early nursery diets decreased overall ADG and ADFI; however, pigs greater than 11 kg had improved ability to compensate for the negative effects of blending the last finisher feed on overall growth performance. Nevertheless, increasing the amounts of finisher feed fed to 11-kg pigs from 0 to 3.75 kg/pig resulted in a linear decrease in overall ADG and ADFI. Economic analysis indicated no change in income-over-feed-cost due to the timing and dose of blending finisher feed into nursery diets.