Effects of Fat Source and Level on Growth Performance, Carcass Characteristics, Carcass Iodine Value and Economics of Finishing Pigs in a Commercial Environment

A total of 2,011 pigs (PIC 1050 × DNA 600; initially 62.4 ± 4.6 lb) were used in a 113-d finishing trial to evaluate the effects of two different fat sources fed at two different levels on growth performance, carcass characteristics, carcass iodine value, and economics of finishing pigs raised in a commercial environment. Pigs were randomly allotted to 1 of 5 dietary treatments with 21 to 27 pigs per pen and 16 pens per treatment. Dietary treatments were arranged in a 2 × 2 + 1 factorial with main effects of fat source and fat inclusion level. Dietary treatments included a control diet containing no added fat. The other 4 dietary treatments included two different fat sources, choice white grease or corn oil, included at either 1 or 3% of the diet. Experimental diets were fed based on a feed budget from d 0 to 113 in 6 phases. For overall growth performance, pigs fed increasing dietary fat from 0 to 3% had increased (linear, P \u3c 0.001) ADG and decreased (linear, P = 0.013) ADFI, which led to an improvement (linear, P \u3c 0.001) in F/G. There was no difference in growth performance between pigs fed choice white grease or corn oil. For carcass characteristics, increasing fat increased (linear, P ≤ 0.017) HCW, carcass yield, and backfat. For carcass fat iodine value, there was a fat source × level interaction (P \u3c 0.001) where iodine value increased linearly as corn oil increased in the diet with only a small increase in iodine value when diets with choice white grease were fed. For economics, increasing fat, regardless of fat source, increased feed cost (linear, P \u3c 0.001) and revenue (linear, P = 0.003). Increasing fat reduced (linear, P \u3c 0.001) IOFC in the high feed cost, low revenue scenario, and tended to increase (P = 0.060) IOFC in the low feed cost, high revenue scenario. In conclusion, increasing fat from 0 to 3% of the diet, regardless of fat source, increased overall ADG, reduced ADFI, and improved F/G. Increasing fat also increased HCW, carcass yield, and backfat, while pigs fed diets containing corn oil had higher carcass fat iodine values. When feed costs are high and revenue is low, the improvement in growth performance does not justify the extra diet cost from increasing added fat from 0 to 3% in the diet. However, adding fat in the diet is justifiable when feed costs are low and revenue is high, regardless of fat source used

Effects of Extruded-Expelled Soybean Meal and Benzoic Acid on Growth Performance, Carcass Characteristics, and Carcass Iodine Value of Finishing Pigs

A total of 2,162 pigs (PIC 1050 × DNA 600; initially 69.2 ± 4.9 lb) were used in a 109-d finishing trial to evaluate the effects of extruded-expelled soybean meal (EESBM) and benzoic acid on growth performance, carcass characteristics, and carcass iodine value. Pigs were randomly allotted to 1 of 4 treatments with 27 to 28 pigs per pen and 20 pens per treatment. Dietary treatments were arranged in a 2 × 2 factorial with main effects of soybean meal source and benzoic acid. Diets contained either conventional soybean meal (SBM) or extruded-expelled soybean meal (EESBM; Lester Feed and Grain, Lester, IA) with or without 0.25% VevoVitall (DSM Products; Parsippany, NJ), a source of benzoic acid. The EESBM was analyzed to be 43.2% CP and 7.73% fat (acid hydrolysis). Experimental diets were not balanced for energy, but rather formulated to the same SID Lys:ME ratio and fed based on a feed budget from d 0 to 109 in 6 phases. Overall (d 0 to 109), there were no interactions between soybean meal source and benzoic acid addition. There was a main effect of soybean meal source where pigs fed conventional SBM had greater (P = 0.01) ADFI compared to pigs fed EESBM without influencing ADG, resulting in improved (P \u3c 0.001) F/G. Also, pigs fed diets without benzoic acid had greater (P = 0.02) ADFI compared to pigs fed diets that contained benzoic acid without influencing ADG, resulting in pigs fed benzoic acid having improved (P = 0.01) F/G. When evaluating caloric efficiency, pigs fed diets containing benzoic acid had improved (P \u3c 0.001) caloric efficiency compared to pigs fed diets without benzoic acid, with soybean meal source not having any impact. For carcass characteristics, pigs fed EESBM had increased (P \u3c 0.001) carcass fat iodine value compared to pigs fed conventional SBM. For economics, there was a main effect of soybean meal source where pigs fed EESBM had a higher (P ≤ 0.002) feed cost per pig placed in the low and high feed cost scenarios. There were no differences in revenue per pig placed in the low or high revenue scenarios regardless of soybean meal source or the inclusion of benzoic acid. Pigs fed conventional SBM had a higher (P ≤ 0.02) income over feed cost (IOFC) compared to pigs fed EESBM in the high feed cost, high revenue; high feed cost, low revenue; and low feed cost, low revenue scenarios. In summary, replacing conventional SBM with EESBM improved feed efficiency, but due to increased feed cost without influencing gain, it was less economical as measured by IOFC. Also, the addition of benzoic acid improved feed efficiency but did not improve IOFC