Effect of nursery feeding program on serum haptoglobin, growth performance, and carcass characteristics of pigs reared on commercial farms.

A total of 774 pigs were enrolled in 13 cohorts across 7 commercial farms to examine the effect of nursery feeding program on serum haptoglobin, subsequent growth performance, and carcass characteristics of finishing pigs. Pigs were weaned [23.4 ± 0.2 days of age and 5.3 ± 1.5 kg body weight (BW)] and randomly assigned to either a complex (HC: highly digestible sources of proteins, including animal proteins; N = 346) or simple (LC: corn- and soybean meal-based; N = 340) diet for 37.7 ± 1.7 days over 3 phases (1 pen per diet per cohort; pen was the experimental unit; n = 13); sex was balanced between treatments. Thereafter, pigs received common grower-finisher diets. At a targeted BW of 118 kg, pigs (subset: n = 275 and 258 for HC and LC, respectively) were processed to evaluate carcass characteristics. Nursery feeding program did not influence BW, BW gain, or serum haptoglobin at any stage of production. Feed cost was reduced by $2.82 per pig during the nursery period for the LC-fed pigs (P < 0.001). Loin eye depth, back fat depth, carcass weight, percent lean yield, and carcass gross revenue at slaughter were not influenced by nursery feeding program. Feeding LC nursery diets on commercial farms is a feasible way to reduce feed cost without negatively impacting serum haptoglobin, growth performance during or after the nursery period, or carcass value. Copyright and/or publishing rights held by the Canadian Veterinary Medical Association.