250 Evaluation of growth performance and mortality rates of late finisher pigs stocked at 2 different stocking densities and fed 3 different dietary soybean meal inclusion levels Free

Abstract

Stocking pens of pigs at high densities can create competition for resources and lead to aggressive behaviors resulting in stress, injury or death. Soybean meal (SBM) may pose benefit to pigs that are in pens stocked at higher densities by modulating inflammatory responses, mitigating stress, and improving feed efficiency. The objective was to determine if increasing SBM inclusion in the diet fed to pigs stocked in high density pens would improve growth performance and decrease mortality. A total of 2,067 pigs (barrows and gilts; PIC 337 sire × PIC 1050 dam; Pig Improvement Company, Hendersonville, TN) were used in a 64-day experiment. Dietary treatments were fed in a 2 × 3 factorial arrangement of treatments in a randomized complete block design. Factors included stocking density at 26 pigs per pen (0.66 m²/pig) or 27 pigs per pen (0.63 m²/pig) and SBM inclusion (7%, 12%, or 17%). The metabolizable energy ratio of SBM was at 97% energy of corn on a dry matter basis. Each pen had approximately the same number of barrows and gilts. Body weight and feed intake were recorded on a pen basis and summarized at day 0 (start of experimental feeding period), 23, 42, and 48 to calculate average daily gain (ADG), average daily feed intake (ADFI), and gain-to-feed ratio (G:F). The percentage of pigs removed was calculated for each phase and cumulatively. The date, weight, and reason for mortality or morbidity were recorded for all removed pigs. The number of tail, ear, and flank bites per pen were recorded. The starting weights were unbalanced across levels of stocking density therefore the starting weight was used as a covariate for all response variables. There were no significant interactions between stocking density and SBM inclusion throughout all phases. Allometric k-values in the low stocking density groups were greater (P < 0.01) during all phases compared to the higher stocked groups. Cumulatively, there were no differences (P ≥ 0.47) in ADG or ADFI for stocking density or SBM inclusion. Gain-to-feed tended to be improved (P = 0.06) by 0.01 units for pigs fed 7% SBM compared to pigs fed 17% SBM. Cumulative including marketing, there were no differences (P ≥ 0.31) for ADG, ADFI, or G:F for stocking density or SBM inclusion. Overall, caloric efficiency was not different (P ≥ 0.26) for stocking density or SBM inclusion. There were no differences (P ≥ 0.16) in total lesions, flank bites, or tail bites by stocking density or SBM inclusion during the phases measured. There was no difference (P ≥ 0.53) in mortality for stocking density or SBM inclusion throughout all phases and cumulative. In conclusion, growth performance and mortality rates did not differ among SBM inclusions regardless of stocking density.