Effects of added Zn in diets with Ractopamine HCl on growth performance and carcass quality of finishing pigs in a commercial environment

The experiment was conducted in a commercial facility to determine the effects of added Zn on the performance of finishing pigs fed Ractopamine HCl (RAC; Paylean®; Elanco Animal Health, Greenfield, IN). Pigs were randomly assigned to pens based on gender (14 barrow pens, 11 gilt pens, and 23 mixed-gender pens), with 25 to 28 pigs per pen. Previously, pens of pigs were assigned to treatments containing 0, 7.5, or 15% bakery by-product in a completely randomized design while balancing for initial BW and gender. On d 75, treatments were implemented to determine the effects of adding 50 ppm Zn from ZnO on finishing pig performance. A total of 1,234 pigs (PIC 337 × 1050; average BW 224.6 lb) were used in a 28-d study. Pens of pigs were randomly assigned to diets with and without 50 ppm added Zn from zinc oxide (ZnO) and balanced by BW, bakery by-product, and gender. All diets contained 5 ppm RAC and 83 ppm Zn from ZnO provided by the trace mineral premix. There were 24 pens per treatment. Overall (d 75 to 102), no differences (P > 0.22) in growth performance or carcass characteristics were observed when pigs were fed diets with 50 ppm added Zn compared with the RAC control. For pigs subsampled on d 84, pigs fed diets with 50 ppm added Zn had decreased (P < 0.05) edge belly thickness compared with pigs fed the control. For pigs subsampled on d 102, pigs fed diets with 50 ppm added Zn had decreased (P < 0.02) backfat thickness, belly weight, and edge belly thickness; a tendency for decreased (P < 0.07) middle belly thickness; and increased (P < 0.01) percentage lean compared with pigs fed the RAC control. In contrast with our previous research, these data indicate that adding 50 ppm Zn from ZnO to finishing pig diets containing RAC did not improve overall performance. Consistent with the earlier research, income over feed cost (IOFC) was numerically increased with the addition of Zn

Effects of adding enzymes to diets containing high levels of dried distillers grains with solubles on growth performance of finishing pigs

A total of 1,032 pigs (BW = 101.5 lb) were used in a 90-d experiment to determine the effects of adding enzymes to diets containing high levels of dried distillers grains with solubles (DDGS) on growth performance and carcass characteristics of finishing pigs. Pigs were blocked by BW and randomly allotted to 1 of 7 dietary treatments with 6 pens per treatment. The control diet contained 30% DDGS. The remaining treatments were arranged in a 2 × 3 factorial design based on DDGS (45 or 60%) and enzyme inclusion (none, product A, or product B). Enzyme products were commercially available and designed for use in swine diets containing DDGS. Pigs allotted to the 60% DDGS treatment were fed 45% DDGS during the first 2 wk of the experiment to acclimate the pigs to DDGS. The 4 heaviest pigs from each pen were sold at d 78, and DDGS levels for all treatments were decreased to 20% until the end of the trial. Overall (d 0 to 90), enzyme supplementation did not affect ADG (P > 0.24), ADFI (P > 0.30), or F/G (P > 0.52). From d 0 to 78, regardless of enzyme treatment, ADG decreased (linear; P 0.17) overall ADG, F/G, or final weight. There were no differences in carcass weight and yield (P > 0.65) or in backfat, loin depth, percentage lean, and fat-free lean index (P > 0.38) after adjusting to a common carcass weight. Increasing dietary DDGS increased (linear; P < 0.01) iodine value of belly fat (77.2, 83.7, and 87.3 g/100 g, respectively). This study indicates that up to 60% DDGS may be added to pig diets without negatively affecting growth performance or carcass traits compared to 30% DDGS when levels are reduced to 20% for 12 d before market; however, fat iodine values will be significantly increased. Neither commercially available enzyme product had any effect on pig growth performance

Effects of increasing dietary bakery by-product on growing-finishing pig growth performance and carcass quality

A total of 1,263 pigs (PIC 337 × 1050; initially 77.8 lb) were used in a 102-d study to determine the effects of dietary bakery by-product on pig growth performance and carcass quality. Pigs were randomly assigned to pens based on gender (14 barrow pens, 11 gilt pens, and 23 mixed-gender pens). Pens of pigs were allotted to 1 of 3 dietary treatments in a completely randomized design while balancing for initial BW and gender. Dietary treatments included 0, 7.5, and 15% bakery by-product. On d 84, the 5 heaviest pigs from each pen (determined visually) were sold according to the normal marketing procedure of the farm. On d 102, the remaining pigs were individually tattooed by pen number and sent to harvest to allow for collection of carcass data. On d 84 and d 102, the median weight market pig from every pen was selected (determined visually) for collection of carcass quality measurements

Effects of feed-withdrawal time on finishing- pig carcass characteristics and economics in a commercial environment

The effects of feed-withdrawal time on finishing-pig carcass composition and net returns were determined in 2 studies. In Exp. 1, a total of 728 pigs (BW = 286.4 ± 2.7 lb, 10 to 19 pigs per pen) were marketed from 48 pens that were randomly assigned to 1 of 4 treatments: feed withdrawal times of 7, 24, 36, or 48 h before harvest. Pigs were fed a common corn-soybean meal diet containing dried distillers grains with solubles (DDGS) and bakery co-products. As expected, increased feed withdrawal time decreased (linear; P < 0.001) live weight. Withholding feed also decreased (linear; P < 0.03) HCW and backfat depth. Percentage yield increased (quadratic; P < 0.01) with longer withdrawal periods, as did percentage lean (linear; P < 0.01). Withholding feed increased (quadratic; P < 0.01) live price and, accordingly, also increased (linear; P < 0.001) carcass price. These results were due in part to increased (linear; P < 0.02) premiums and decreased (linear; P < 0.01) weight discounts. Total value and net revenue received were similar (P > 0.32) between treatments as HCW decreased in fasted pigs, but feed intake per pig also decreased (quadratic; P <0.001), resulting in feed savings of up to $0.78/pig. Withholding feed for 24 h resulted in a numeric increase in net revenue of$0.89/pig compared to 7 h. In Exp. 2, the 48-h treatment was removed and replaced with a 12-h treatment in order to more accurately determine the proper time to implement feed withdrawal. The incidence of runny bung and leaking ingesta were also recorded to determine whether a relationship existed between feed withdrawal and the incidence of these processing concerns. A total of 843 pigs (BW = 273.0 lb, 16 to 26 pigs per pen) were assigned to 1 of 4 treatments: withholding feed for 7, 12, 24, or 36 h before harvest. Pigs were fed a common corn-soybean meal-based diet containing 20% DDGS. As a result of misidentification of pigs by plant personnel, data were analyzed from only 25 of the original 40 pens. Withholding feed tended to decrease (linear; P < 0.09) live weight. Unlike Exp. 1, there were no differences (P > 0.22) in HCW, percentage lean, or backfat depth across treatments. However, as in Exp.1, percentage yield (linear; P < 0.001) increased with increasing withdrawal time. Although withholding feed had no effect (P > 0.31) on the incidence of runny bung, it did increase (linear; P < 0.001) the incidence of leaking ingesta. For economics, as in Exp. 1, withholding feed increased (linear; P < 0.002) live price. Additionally, pigs that were fasted had increased (quadratic; P < 0.05) carcass price. Although premiums were similar (P > 0.32) across treatments, withholding feed decreased (quadratic; P < 0.04) weight discounts. Total value and net revenue received per pig were similar (P > 0.88) across treatments, but withholding feed decreased (linear; P < 0.001) feed intake, resulting in feed savings of up to $0.46/pig. Overall, withholding feed can be used to avoid weight discounts in heavyweight pigs without negatively impacting carcass composition and maintaining overall revenue per pig. However, these advantages come with a potential reduction in carcass weight and increased incidence of leaking ingesta, which can result in condemned heads at inspection and losses of$3 to 4 per carcass