An Evaluation of Soybean Meal Inclusion Rate in Pigs Fed from Wean-to-Market
A. Kramer1, J. Hong1, R. Samuel1, C.L. Levesque1, R.C. Thaler1, and E.M. Weaver1
1South Dakota State University, Brookings, SD
Email: eric.weaver@sdstate.edu
Introduction: An increase in soybean production, driven by renewable energy policies, may increase the soybean meal (SBM) supply. Caloric efficiency or productive energy of SBM closer to the NE of corn has been reported (Boyd and Gaines, 2023) which may increase its relative value in formulations. Objective: To evaluate the effect of SBM level in two common diet formulation strategies, Corn-DDGS-SBM (DDGS) or Corn-SBM (SBM) with synthetic amino acid additions (0.5%, 0.25% or no added Lysine HCl) in wean-to-market pigs.
Materials and Methods: A total of 540 pigs (PIC X Duroc, 18 days of age, 5.3 kg) were weaned into two fully-slatted, environmentally-controlled barns. The pigs were blocked by body weight (BW) and sex. Treatments were assigned to pen in a randomized complete block design. Individual BW and pen feed disappearance (ADF) were collected every two weeks for 18 weeks and carcass data were collected at marketing between 18 and 20 weeks. Each pen (1.8 × 2.4 m) was equipped with a dry-feeder (3 spaces) and one cup waterer for ad libitum access to feed and water. All diets were formulated to a SID lysine:NE target by phase using current NE estimates for SBM, 2,087 Kcal/kg (NRC, 2012). The NE used for DDGS was 2,343 Kcal/kg. The treatments consisted of high, medium and low SBM levels by providing 0.5%, 0.25% and no added lysine (AA) in either a corn-SBM or corn-DDGS based diet formulation. The diets were fed in mash form and formulated to meet or exceed NRC requirements, including the amino acid pattern, by phase of production. Data were analyzed using the as a randomized complete block design with pen as the experimental unit for performance data and the pig as the experimental unit for carcass data. Data were analyzed using the MIXED procedure (SAS Inst. Inc., Cary, NC) P < 0.05 was considered significant and 0.05 = P < 0.10 considered a tendency.
Results and Discussion: Interactions between amino acid additions and diet type were observed only for BW and average daily gain (ADG) in the growing phase. Nursery Phase: SBM increased week 6 BW and ADG compared to DDGS (P<0.05). Intact SBM and 0.25% AA additions increased week 6 BW weights and ADG vs 0.5% AA (P<0.05). Feed intake and G:F ratio was unaffected by dietary treatment. Growing Phase: SBM increased week 14 BW and ADG compared to DDGS (P<0.05) except for 0.25% AA in DDGS diets, which were not different. Intact SBM and 0.25% AA additions increased week 14 BW weights and ADG vs 0.5% AA (P<0.05). Feed intake was also unaffected by dietary treatment. Finishing Phase: SBM increased week 18 BW and ADG compared to DDGS (P<0.05). Intact SBM and 0.25% AA additions increased week 18 BW and ADG vs 0.5% AA (P<0.05). Feed intake was unaffected by dietary treatment which resulted in 4% improvements in feed and caloric conversion from weaning to 18 weeks. Marketing: Carcass data were obtained on 456 of the 524 full-value pigs marketed (97% of pigs allocated). SBM addition increased hot carcass weight 4.2 lbs, loin depth, BF, and calculated lean weight, compared to DDGS (P<0.05). AA additions of 0.5% resulted in more BF, less loin depth and less lean weight compared to the use of 0.25% or no AA, i.e. higher levels of SBM.
Implications: Higher SBM levels and/or 0.25% amino acid addition resulted in improved growth, feed and caloric conversion, and increased carcass value in high-performance WTM pigs compared to the use of DDGS and 0.5% amino acid additions. While economic conditions for feed ingredients and carcass value vary, formulations for best economic outcome should consider that high-performing pigs benefit from the health and nutritional components contained in SBM.
Acknowledgments: Lauren Olson, Shannon Dierking, Caitlyn Sullivan,