Effects of feeding cracked corn to nursery and finishing pigs.

Four experiments were conducted to determine the effects of supplementing cracked corn in nursery and finishing pig diets (PIC TR4 × 1050). In Exp. 1, 144 pigs (7.5 kg BW) were used in a 28-d experiment with 6 pigs per pen and 6 pens per treatment. Treatments were corn-soybean meal based in the form of mash, pellets (PCD), and pellets with 100% of the corn ground (PGr; 618 mm) or cracked (PCr; 3444 mm) and blended into the diet after the rest of the formulation had been pelleted. For d 0 to 28, pigs fed mash had increased (P = 0.042) ADFI compared with those fed the PCD diet. Pigs fed PCD had increased (P < 0.05) ADG and G:F compared with pigs fed PGr and PCr. Pigs fed PCr had decreased (P = 0.004) G:F compared with those fed PGr. For Exp. 2, 224 nursery pigs (7.4 kg BW) were used in a 28-d study with 7 pigs per pen and 8 pens per treatment. Treatments were similar to Exp. 1, with 50% of the corn either ground (445 mm) or cracked (2142 mm). For d 0 to 28, pigs fed mash had greater (P < 0.05) ADFI and G:F than pigs fed the PCD diet. Pigs fed the PCD diet had decreased (P = 0.001) ADFI and increased (P = 0.001) G:F compared to those fed PGr and PCr. For Exp. 3, 208 pigs (62.6 kg BW) were used in a 63-d experiment with 13 pigs per pen and 4 pens per treatment. Treatments were corn-soybean meal based with 0, 10, 20, and 40% cracked corn (3549 µm). All treatments were fed in mash form. For d 0 to 63, increasing cracked corn tended to decrease (linear, P = 0.093) G:F and decreased (linear, P = 0.047) carcass yield. Adding up to 40% of cracked corn to a mash diet decreased (P < 0.05) scores for keratinization and ulcers. For Exp. 4, 252 finishing pigs (40 kg BW) were used with 7 pigs per pen and 9 pens per treatment. The treatments were the same as described in Exp. 2. For the 80-d experiment, pigs fed mash had decreased (P < 0.05) ADG, stomach keratinization, and ulcer scores and increased (P < 0.05) yield and loin depth compared with pigs fed the PCD diet. Pigs fed PCD had increased (P < 0.05) ADG and G:F and decreased (P = 0.026) loin depth compared with pigs fed PGr and PCr diets. Pigs fed PCr had increased (P = 0.023) ADG and decreased (P = 0.001) yield compared with pigs fed PGr. Pigs fed PCr had decreased (P < 0.05) stomach keratinization and ulcer scores compared with pigs fed the PCD and PGr diets. In conclusion, pigs fed PCD had the greatest G:F, and PGr and PCr treatments had negative effects on G:F of pigs. Scores for stomach lesions were lowest for pigs fed PCr.

Effect of crude glycerol on pellet mill production and nursery pig growth performance.

The objective of this study was to determine the effects of diets containing crude glycerol on pellet mill production efficiency and nursery pig growth performance. In a pilot study, increasing crude glycerol (0, 3, 6, 9, 12, and 15%) in a corn-soybean meal diet was evaluated for pellet mill production efficiency. All diets were steam conditioned to 65.5 degrees C and pelleted through a pellet mill equipped with a die that had an effective thickness of 31.8 mm and holes 3.96 mm in diameter. Each diet was replicated by manufacturing a new batch of feed 3 times. Increasing crude glycerol increased both the standard (linear and quadratic, P < 0.01) and modified (linear, P < 0.01; quadratic, P

Predicting effective caloric value of nonnutritive factors: III. Feed form affects broiler performance by modifying behavior patterns.

Two trials of an experiment were conducted to confirm the relationships among effective caloric value (ECV) of the diet, net energy for gain (NEg), BW, feed conversion ratio (FCR), and broiler behavior. Further, we sought to examine such factors with benefits of pelleting, including feed form history (pellets vs. mash) in females from 2 strains of commercial broilers. Composition of gain was measured on a sample of birds in both trials. In trial 1 birds were reared to 23 d on feed in crumble form, when the birds were provided a feed in pellet or mash form for 7 d. Pelleting the feed increased ECV and total NEg, while decreasing eating and increasing resting behavior. Significant correlations (P < 0.05) among resting, NEg, and ECV occurred. In trial 2, birds were reared to 23 d on a crumble diet and then fed diet in mash or pellet form to 36 d. At 37 d of age, half of the birds from each strain and feed form history combination were switched to the alternative feed form. Interactions of strain by grower feed form were present for BW, initial fat, and body energy content indicating that pelleted feed was required for optimum broiler performance of 1 strain. Grower feed form by finisher feed form interactions were present and demonstrated that birds switched from pellets or mash to the alternate feed form consumed more feed in less time than birds that remained on their previous feed form. Significant correlations were observed in both trials between behaviors and FCR and ECV, whereas NEg reflected these differences in trial 1 but not trial 2. Regression analysis indicated that FCR and subsequently ECV were best predicted by lean gain, whereas NEg was best predicted by fat gain. Further, regression analysis established interactive equations in which ECV was predicted (R2 > 0.99) by eating and resting behavior. The results of these trials indicate that the effects of feed form are caused by a modification of behavior patterns, that ECV is responsive to such behavior changes, and that ECV is an effective estimator of the relative caloric value of genetic, management, and husbandry influences.

Predicting effective caloric value of nonnutritive factors: I. Pellet quality and II. Prediction of consequential formulation dead zones.

Two experiments were conducted with male broilers to 1) establish a methodology for predicting effective caloric value (ECV), defined as dietary caloric density (CD) necessary for broilers to achieve specific BW and feed conversion ratio (FCR) combinations under standardized conditions and 2) quantify the ECV attributable to pellet quality (PQ), defined as the pellet to pellet fines ratio in the feeder. In experiment 1, chicks were reared to 56 d on diets varying in CD. Dietary caloric densities examined ranged from 2,650 to 3,250 kcal of MEn/kg. Pen BW, feed intake, and FCR were measured at 21, 42, and 56 d. On 42 and 56 d, carcass traits were measured. Increasing CD significantly enhanced BW, energy consumption, and FCR. Feed intake remained similar across the upper 3 CD treatments to 42 d. By d 56, feed consumption tended to decline as CD increased. Increasing CD beyond 3,066 kcal of MEn/kg diet did not increase lean tissue accretion, while fat deposition rose disproportionately. Experiment 1 results enabled development of equations whereby CD, hence ECV, might be predicted using BW and FCR. In experiment 2, 38-d-old broilers were used to evaluate PQ effects on growth, feed intake, FCR, and behavior in a 7-d FCR assay. The BW gain and FCR were significantly enhanced by pelleting and were positively correlated with PQ. Feed intake was not affected by PQ. The experiment 1 model was validated for experiment 2, as it closely estimated the CD for diets of similar PQ used in experiment 1. Results suggest pelleting contributes 187 kcal/kg of diet at 100% PQ and that the ECV declines curvilinearly as PQ falls. Birds were observed eating less and resting more as PQ increased, suggesting that ECV of pelleting is mediated by energy expenditure for activity. These studies provide a method for estimating ECV of nonnutritive factors that impact BW, FCR, or both. Further, the application reveals potential for creation of formulation "dead zones" whereby dietary changes to enhance CD may be offset due to reduced ECV.

Effects of pelleting and pellet conditioning temperatures on weanling pig performance.

We conducted two experiments to study the effects of pelleting and pellet conditioning temperature on weanling pig performance. In Exp. 1, 252 weanling pigs (PIC, L326 x C22) averaging 6.0 +/- 1.3 kg and 21 +/- 3 d of age were used to evaluate six corn-soybean meal-based diets containing 15% dried whey and formulated to contain 1.4% lysine. Treatments consisted of a control diet without spray-dried animal protein (SDAP) fed in meal form, a diet with 5% SDAP fed in meal form, and four diets with 5% SDAP that were conditioned at 60, 66, 71, or 77 degrees C for 10 s prior to pelleting. Pellets had a 3.97-mm diameter. The experimental diets were fed from d 0 to 14 after weaning, and all pigs were fed a common diet in meal form from d 14 to 28 after weaning. From d 0 to 7 after weaning, pigs fed diets containing SDAP had greater ADG, gain/feed (P < 0.001), and ADFI (P < 0.05) than pigs fed the control diet. No differences (P > 0.10) were observed between pigs fed the pelleted diets and those fed the SDAP diet in meal form. Conditioning temperature had no effect (P > 0.10) on weanling pig performance from d 0 to 14, and the diet fed from d 0 to 14 had no effect on overall performance (d 0 to 28). In Exp. 2, 252 weanling pigs (6.3 +/- 1.5 kg and 22 +/- 4 d of age) were used to evaluate diets with same composition as in Exp. 1, but treatments consisted of diets with or without SDAP conditioned at 60 degrees C before pelleting, and four diets containing 5% SDAP that were conditioned at 68, 77, 85, and 93 degrees C before pelleting. As in Exp. 1, conditioning lasted 10 s, pellets were 3.97 in mm diameter, and experimental diets were fed for the first 14 d of the 28-d experiment. From d 0 to 7, pigs fed the SDAP diet conditioned at 60 degrees C had greater ADFI (P < 0.05) and tended (P = 0.12) to have greater ADG than pigs fed the diet without SDAP and conditioned at 60 degrees C. From d 0 to 7, ADG (quadratic effect, P < 0.03) and ADFI (linear effect, P < 0.002) decreased as conditioning temperature increased, with the largest decrease observed above 77 degrees C. From d 0 to 14 and 0 to 28, ADG was not affected (P > 0.10) by pellet conditioning temperature or SDAP fed from d 0 to 14. The results of these studies suggest that conditioning diets containing 5% SDAP at temperatures above 77 degrees C decreases weanling pig growth performance.