J. Soto

Determination of the Optimum Standardized Ileal Digestible Lysine Concentration for Finishing Pigs from 225 to 280 lb

The objective of this study was to determine the standardized ileal digestible (SID) Lys requirement for growth and carcass performance of 225to 280-lb finishing pigs. A total of 253 pigs (DNA 600 × 241, initially 224.9 lb BW) were used in a 23-d trial. Pens were blocked by BW and were randomly assigned to diets with 7 or 8 pigs per pen and 8 pens per treatment in a randomized complete block design. Diets were corn and soybean meal-based and fed in meal form. Dietary treatments consisted of 0.45, 0.55, 0.65, or 0.75% SID Lys. Increasing SID Lys increased (quadratic, P < 0.05) ADG and ADFI, resulting in pigs fed 0.55% SID Lys having the greatest final BW. A marginal significant improvement (quadratic, P < 0.10) was observed in F/G and caloric efficiency with increasing SID Lys. A marginal significant increase in carcass yield (linear, P < 0.10) and reduction (quadratic, P < 0.10) in backfat was also observed with increasing SID Lys. Carcass ADG increased (linear, P < 0.05) and carcass G:F was marginally improved (quadratic, P = 0.063), resulting in pigs fed 0.55% SID Lys having the greatest HCW. Furthermore, there was a marginal significant improvement (quadratic, P = 0.053) in carcass caloric efficiency on NE basis with increasing SID Lys. For ADG, quadratic polynomial (QP) model resulted in the best fit (BIC = 361.7) predicting 95, 98, and 100% of maximum growth at 0.50, 0.55, and 0.62% SID Lys, respectively. The QP and broken line linear (BLL) models had a comparable fit for F/G (BIC = 278.2 vs. 279.3, QP and BLL, respectively) with the QP model predicting 95, 98, and 100% of maximum feed efficiency at 0.48, 0.54, and 0.63% SID Lys, respectively. The BLL model predicted no further improvement in F/G over 0.55% SID Lys. In summary, the SID Lys requirement to obtain 100% of maximum response in this experiment was 0.62 and 0.63% for ADG and feed efficiency, respectively.

Regression Analysis to Predict the Impact of High Neutral Detergent Fiber Ingredients on Carcass Yield

Research has shown that carcass yield is reduced when feeding distillers dried grains with solubles (DDGS) or other high fiber ingredients. Considering the financial implications of changing carcass yield, the objective of this project was to develop regression equations to accurately estimate carcass yield from dietary NDF withdrawal strategies. Data from 8 trials originating from 5 journal articles, 2 theses, and 1 technical memo were used to develop a regression equation to predict carcass yield. The regression analysis showed that number of days in the withdrawal period (WP), NDF level in the dietary phase prior to the final phase (NDF1), NDF level in the last dietary phase before marketing (NDF2), and the interaction between NDF2 and WP (NDF2 × WP), were the most important variables in the dataset to predict carcass yield. The resulting regression equation: carcass yield, % = 0.03492 × WP (d) – 0.05092 × NDF1 (%) – 0.06897 × NDF2 (%) – 0.00289 (NDF2 (%) × WP (d)) + 76.0769 may be used to predict the influence of dietary NDF and NDF withdrawal strategy on carcass yield.

Optimizing Dietary Net Energy for Maximum Profitability in Growing- Finishing Pigs

Feed accounts for a significant portion of swine production cost, with dietary energy alone representing more than half of the total cost. Considering the financial implications of determining the energy content of the diet, the objective of this research project was to develop a tool to accurately estimate the dietary NE content that yields maximum profitability for growing-finishing pigs. A Microsoft Excel®-based model was developed to contrast dietary NE defined by the user with recommended concentrations that are intended to maximize profitability in user defined production and economic scenarios. To calculate pig performance, the model uses prediction equations for ADG and feed efficiency. In addition, the model also uses the NDF content of the diet because of its effect on dressing percentage. For profitability calculations, a non-linear mathematical programming model was designed to select the optimum dietary NE content that yields the greatest income over total cost per pig on a live or carcass basis. The model can be used to predict dietary NE content that yields the highest economic benefit considering dynamic productive and economic scenarios. The model can be downloaded at www.ksuswine.org.

Evaluation of High Standardized Ileal Digestible Tryptophan:Lysine Ratios with Ractopamine HCl on Growth and Carcass Performance of Pigs from 240 to 295 lb

A total of 935 pigs (PIC 1050 × 337, initially 237.2 lb BW) were used in a 22-d trial to determine the effects of feeding high levels of standardized ileal digestible (SID) Trp:Lys ratio in diets with ractopamine HCl (RAC, Paylean, Elanco Animal Health, Greenfield, IN) on growth and carcass performance of finishing pigs. Pens of 23 or 24 pigs were allotted by BW and randomly assigned to 1 of 5 dietary treatments with 8 replications per treatment. The dietary treatments included 5 SID Trp:Lys ratios (20, 22, 24, 26, and 28% of Lys). All diets were formulated to 0.90% SID Lys and contained 10 ppm ractopamine. At d 22, pigs were transported to a packing plant for processing and carcass data collection. For overall growth performance, increasing SID Trp:Lys increased (linear, P < 0.05) ADFI and SID Trp g/kg gain. However, there was no evidence for treatment differences for ADG or F/G. For carcass characteristics, there was no evidence for treatment differences for HCW, carcass yield, backfat loin depth, lean, carcass ADG, or carcass feed efficiency. In summary, increasing SID Trp:Lys increased ADFI and SID Trp g/kg gain, however, there was no evidence for treatment differences for other growth or carcass parameters measured.

Effects of Dietary Soybean Meal Concentration with Dietary Crude Protein Fixed at 12% on Growth and Carcass Performance of Finishing Pigs from 250 to 300 lb

A total of 280 pigs (DNA 600 × 241, initially 251.8 lb) were used in a 23-d trial to determine the effects of dietary soybean meal (SBM) concentration with dietary crude protein, fixed at 12%, on growth performance of finishing pigs from 250 to 300 lb. Pens of 7 or 8 pigs were allotted by BW and randomly assigned to 1 of 6 dietary treatments with 6 replications per treatment. Treatments consisting of 5 levels of SBM (10.6, 7.7, 4.9, 2.7, and 0%) with 12% CP and a negative control treatment with 4.0% SBM and 10% CP. Corn gluten meal was increased as SBM decreased to maintain the 12% CP. At d 23, pigs were transported to a packing plant for processing and carcass data collection. For overall growth performance, decreasing SBM marginally decreased (linear, P < 0.10) ADG. Decreasing SBM increased (linear, P < 0.05) ADFI with the highest intake in pigs that were fed 2.7% SBM. The high ADFI worsened (linear, P < 0.05) F/G and caloric efficiency, resulting in pigs fed 2.7% SBM having the poorest caloric efficiency. Feed intake was lowered (P < 0.05) in pigs fed the diet with 12% CP and 10.6% SBM compared with pigs fed the diet with 10% CP and 4.0% SBM, resulting in a marginal improvement (P < 0.10) in F/G and caloric efficiency for pigs fed the 12% CP and 10.6% SBM diet. For carcass characteristics, decreasing SBM decreased (linear, P < 0.05) carcass ADG and worsened (linear, P < 0.05) carcass feed efficiency and caloric efficiency. Pigs fed the diet with 12% CP and 10.6% SBM had improved (P < 0.05) F/ G and marginally improved (P < 0.10) carcass caloric efficiency compared with pigs fed the diet with 10% CP and 4.0% SBM. In conclusion, regardless of the 12% CP level, reducing the concentration of SBM worsened ADG, F/G, caloric efficiency, carcass ADG, and carcass feed efficiency, and caloric efficiency. In addition, pigs fed the 12% CP and 10.6% SBM had improved F/G, caloric efficiency, carcass feed efficiency, and carcass caloric efficiency, compared with pigs fed the negative control diet with 10% CP.

Optimum Level of Dietary Crude Protein for Growth Performance and Carcass Characteristics of Finishing Pigs from 245 to 300 lb

A total of 238 pigs (DNA 600 × 241, initially 246.4 lb) were used in a 26-d trial to determine the optimum dietary CP concentration for growth performance and carcass characteristics of finishing pigs. Pens of 7 or 8 pigs were allotted by BW and randomly assigned to 1 of 5 dietary treatments with 6 replications per treatment. Dietary treatments included 5 levels of CP (9, 10, 11, 12, and 13%) that were formed by reducing the amount of feed-grade amino acids and increasing soybean meal in a corn-based diet. At d 26, pigs were transported to a packing plant for processing and carcass data collection. For overall growth performance, increasing CP improved (quadratic, P < 0.05) ADG, F/G, and caloric efficiency with the greatest improvement as CP was increased from 9 to 11% with smaller, continued improvements as CP was further increased to 13%. For carcass characteristics, increasing CP increased (quadratic, P < 0.05) carcass ADG and improved (quadratic, P < 0.05) carcass feed efficiency and carcass caloric efficiency, with the greatest response for pigs fed the diet with 13% CP. Furthermore, increasing CP marginally increased (quadratic, P < 0.10) HCW, with the greatest response for pigs fed the diet with 12% CP. In conclusion, ADG, F/G, caloric efficiency, carcass ADG, carcass feed efficiency, and carcass caloric efficiency were maximized in pigs fed diets with 13% CP. The greatest response for HCW was observed in pigs fed diets with 12% CP.

Effects of Dietary Electrolyte Balance and Crude Protein Level on Growth Performance, Carcass Characteristics, and Blood Analytes of Finishing Pigs

A total of 288 finishing pigs (PIC 327 × 1050, initially 243.5 lb) were used in a 20-d trial to determine if dietary electrolyte balance (dEB) in conjunction with low protein, amino acid fortified diets has any influence on growth performance. Pens of 8 pigs were allotted by BW and randomly assigned to 1 of 4 dietary treatments with 9 replications per treatment. Treatments were arranged in a 2 × 2 factorial with main effects of CP (10 or 13%) and dEB (48 or 107 mEq/kg). At d 20, the pigs were transported to a packing plant for processing and carcass data collection. Pigs fed 13% CP diets had greater (P = 0.001) ADG, heavier (P = 0.037) final body weight, and improved (P < 0.001) feed efficiency compared with pigs fed the 10% CP diets. A tendency for a CP × dEB interaction was observed for ADFI because intake numerically decreased when dEB was increased for pigs fed 10% CP, whereas intake increased as dEB was increased for pigs fed 13% CP diets. For carcass performance, pigs fed the diets with 13% CP had increased (P = 0.001) HCW and HCW ADG and improved (P = 0.001) HCW F/G compared with pigs fed the 10% CP diets. In conclusion, reduced performance observed in pigs fed the low crude protein diets with high supplemental crystalline AA was not influenced by dEB ranging from 48 to 107 mEq/kg. Dietary electrolyte balance in the range tested had no effects on growth performance, HCW, yield, or carcass performance during late finishing. Appropriate levels of dietary CP are critical to ensure optimal late finishing performance.

Determination of the Optimum Levels of Dietary Crude Protein for Growth Performance and Carcass Characteristics of Finishing Pigs from 240 to 280 lb

A total of 224 pigs (PIC 327 × 1050, initially 241.1 lb) were used in a 20-d trial to determine the optimum dietary CP concentration for growth performance and carcass characteristics of finishing pigs. Pens of 7 pigs were allotted by BW and randomly assigned to 1 of 4 dietary treatments with 7 or 8 replications per treatment. Dietary treatments included 4 levels of CP (10, 11, 12, and 13%) that were formed by reducing the amount of crystalline Lys in a corn-soybean meal diet. At d 20, pigs were transported to a packing plant for processing and carcass data collection. For overall growth performance (d 0 to 20), increasing CP increased (linear, P < 0.05 and quadratic, P < 0.10) ADG, ADFI, and HCW ADG with the greatest response for pigs fed the diet with 12% CP. Increasing diet CP also improved (linear, P < 0.05) F/G, NE caloric efficiency, final BW, HCW, and HCW F/G. In conclusion, poorer performance of pigs fed diets under 12% CP was predominantly explained by feed intake but the mechanisms underlying regulation of feed consumption when feeding lower CP remains unclear.