Evaluation of potato proteins on the growth performance of early-weaned pigs.

We conducted five experiments to evaluate conventional and low-glycoalkaloid potato protein (CPP and LGPP, respectively) in diets for early-weaned pigs. In Exp. 1, 150 weanling pigs (initially 4.4 +/- .9 kg and 15.5 +/- 2 d of age) were fed either a control diet containing 3% spray-dried animal plasma (SDAP) or diets with additional SDAP (2.5 or 5% added; 5.5 or 8% total) or CPP (2.6% or 5.1%) substituted on a total lysine basis. From d 0 to 14 after weaning, increasing SDAP increased (linear, P < .05) ADG and ADFI, whereas increasing CCP had no effect on growth performance. In Exp. 2, 180 weanling pigs (initially 5.9 +/- 1.2 kg and 20 +/- 2 d of age) were fed diets containing a LGPP replacing 25, 50, 75, or 100% of the 7% dietary SDAP on a digestible lysine basis. From d 0 to 7 after weaning, increasing LGPP increased and then returned to control levels ADG and ADFI (quadratic, P < .01) and gain:feed ratio (quadratic, P < .05). In Exp. 3, 175 weanling pigs (initially 5.5 +/- 1.1 kg and 20 +/- 3 d of age) were fed either a control diet containing 20% dried whey, 17.5% dried skim milk, and 4% select menhaden fish meal (SMFM) or diets consisting of lactose and either 3.5 and 7.0% SDAP or 4.0 and 8.0% LGPP added at the expense of dried skim milk on a digestible lysine basis. From d 0 to 7 after weaning, ADG and ADFI increased (linear, P < .05) with increasing SDAP. With increasing LGPP, ADG and ADFI increased and then decreased (quadratic, P < .10 and P < .05, respectively). Gain:feed ratio (G/F) was not affected by SDAP and was improved (linear, P < .05) for pigs fed increasing LGPP. In Exp. 4, 270 weanling pigs (initially 6.2 +/- 1.6 kg and 20 +/- 3 d of age) were used to compare three diets that contained either 2.5% spray-dried blood meal (SDBM), 4.8% SMFM, or 3.92% CPP; test feedstuffs were substituted on a total lysine basis and diets were fed from d 7 to 28 after weaning. Pigs fed CPP had decreased (P < .05) ADG and G/F compared with those fed the other protein sources. In Exp. 5, 255 weanling pigs (initially 5.3 +/- 1.2 kg and 17 +/- 2 d of age), were used to compare five diets that contained either 2.5% SDBM, 5.51% SMFM, 4.17% CPP, 4.17% LGPP or 8.34% LGPP; feedstuffs were substituted on a digestible lysine basis and diets were fed from d 7 to 28 after weaning. No differences (P > .10) were observed in growth performance among pigs fed any of the protein sources within the experiment. However, pigs fed the LGPP had numerically greater ADG and better G/F than those fed CPP. In conclusion, these results suggest that LGPP can be an effective replacement for a portion of the SDAP in diets for weanling pigs.

The effects of extrusion processing of carbohydrate sources on weanling pig performance.

Three experiments were conducted to study the effects of extrusion processing on growth performance of weanling pigs. In Exp. 1, 350 weanling pigs (initially 4.4 +/- 1.0 kg BW and 10 +/- 2 d of age) were used to study the effects of various carbohydrate sources (corn, cornstarch, broken rice, wheat flour, and grain sorghum), with or without moist extrusion processing, on growth performance in a 5 x 2 factorial arrangement of treatments. No carbohydrate source x extrusion processing interactions were observed (P > .10). Growth performance was not affected by extrusion processing; however, pigs fed corn had poorer growth performance (P < .05) than those fed other carbohydrate sources. In Exp. 2, 360 weanling pigs (initially 5.0 +/- .5 kg BW and 10 +/- 2 d of age) were used to determine the interactive effects of ingredient processing and diet complexity on growth performance. Three processing combinations were used with either a simple or complex diet formulation in a 3 x 2 factorial arrangement of treatments. The three processing conditions were 1) pelleted only (control); 2) corn that was moist-extruded and then the complete diet was pelleted (extruded); or 3) the complete diet was expanded and then pelleted (expanded). Pigs fed extruded diets had a greater improvement in ADG as diet complexity increased than those fed other diets (processing x diet complexity interaction, P < .10). Pigs fed moist-extruded corn had the best growth performance (P < .01). In Exp. 3, 210 weanling pigs (initially 6.8 +/- 1.5 kg BW and 21 +/- 2 d of age) were fed pelleted diets containing nonextruded corn (14.5% gelatinization; control) or corn extruded to provide 38.7, 52.7, 64.4, or 89.3% gelatinization. Average daily gain and ADFI decreased and then increased (P < .05), but apparent digestibility of DM, CP, and energy (P < .01) increased and then decreased with increasing gelatinization. These results indicate that moist extrusion processing of carbohydrate sources has variable effects on growth performance of early-weaned pigs and that the degree of gelatinization does not seem to be a major factor in explaining this variation.

Evaluation of spray-dried animal plasma and select menhaden fish meal in transition diets of pigs weaned at 12 to 14 days of age and reared in different production systems.

We conducted two experiments with pigs weaned at 12 to 14 d of age to evaluate the effects of adding spray-dried animal plasma (SDAP) and select menhaden fish meal (SMFM) to the diets fed from 5 to 19 (Exp. 1) and 7 to 21 d (Exp. 2) after weaning. This 14-d period represents the transition from the nutrient-dense diet fed to all pigs after weaning to the simpler corn-soybean meal-based diet fed to all pigs for an additional 14 (Exp. 1) or 7 d (Exp. 2) after the experimental period. Pigs averaged 5 kg at the start of the experimental period. In Exp. 1, pigs had a high health status and were weaned to an off-site nursery (SEW) and fed 12 experimental diets in a 3 (0, 2.5, or 5% SDAP) x 4 (0, 2.5, 5, or 7.5% SMFM) factorial arrangement. Diets were formulated to contain 1.6% lysine and contained 20% dried whey, 5% soybean oil, and 2.5% spray-dried blood meal. The SDAP and(or) SMFM replaced corn and soybean meal on an equal lysine basis. Average daily gain and ADFI were not affected by treatment during any period of the experiment. Gain:feed was improved by the addition of SDAP (linear, P < .05) and SMFM (linear, P < .07) during the period from 5 to 19 d. Over the 33-d experiment, SDAP and SMFM improved (linear, P < .05) gain:feed. In Exp. 2, pigs were weaned on-site to an all-in/all-out by room nursery and fed diets identical to those fed in Exp. 1, with 0 or 2.5% SDAP and 0, 2.5, or 5% SMFM in a 2 x 3 factorial arrangement. The addition of 2.5% SDAP improved ADG and gain:feed during the period from 7 to 14 d (P < .05) and 0 to 28 d (P < .10), but not over the period from 7 to 21 d. The addition of SMFM did not affect ADG during any period, but it resulted in a quadratic improvement in gain:feed during the periods from 7 to 14 (P < .05) and 7 to 21 (P < .10) d. These results suggest that high-health SEW pigs respond less to SDAP and SMFM in the transition diet than pigs with a lower health status reared in an on-site nursery. The data further suggest that formulation of transition diets should consider the type of production system if pig performance and diet cost are to be optimized.

Evaluation of the interrelationships among lactose and protein sources in diets for segregated early-weaned pigs.

We conducted two experiments to evaluate the interactions among lactose and protein sources in diets for segregated early-weaned pigs. In Exp. 1, 360 barrows (initially 5.3 kg and 19 +/- 2 d of age) were fed diets containing crystalline lactose (0, 20, and 40%), spray-dried animal plasma (0 and 7.5%), and soybean meal (0 and 20%) in a 3 x 2 x 2 factorial arrangement. We used a blend of select menhaden fish meal and casein to replace the lysine provided by soybean meal or animal plasma. Diets contained 1.7% total lysine and were fed from d 0 to 14 after weaning. Pigs were fed a common diet from d 14 to 34. From d 0 to 14 after weaning, ADG and ADFI increased with increasing dietary lactose when the diet contained soybean meal but decreased when soybean meal was not in the diet (lactose x soybean meal, P < .05 and .10, respectively). Pigs fed animal plasma had increased (P < .05) ADG and ADFI from d 0 to 14 but decreased (P < .05) ADG from d 14 to 34. In Exp. 2, 324 barrows (initially 3.7 kg and 10 +/- 2 d of age) were fed diets from d 0 to 10 similar to those used in Exp. 1 with the exception that extruded soy protein concentrate replaced the lysine provided by soybean meal or animal plasma. From d 0 to 10 after weaning, increasing lactose improved (linear, P < .05) ADG and ADFI, and pigs fed animal plasma had higher ADFI (P < .05). In conclusion, soybean meal had no negative effect on ADG; however, animal plasma and lactose increased ADG and ADFI for pigs weaned between 10 and 19 d of age.

Effects of substituting deproteinized whey and(or) crystalline lactose for dried whey on weanling pig performance.

We conducted two trials to determine the effects of replacing the lactose provided by spray-dried, edible-grade whey with edible-grade deproteinized whey or crystalline lactose on pig performance. In Exp. 1, 180 weanling pigs (initially 4.1 kg and 22 +/- 4 d of age) were allotted randomly to dietary treatments containing 18% lactose supplied by 1) 25% dried whey, 2) 12.5% dried whey and 9% crystalline lactose, 3) 18% crystalline lactose, 4) 12.5% dried whey and 10.9% deproteinized whey, or 5) 21.7% deproteinized whey. Casein was used to replace the lysine provided by dried whey in diets containing lactose and deproteinized whey. From d 0 to 14 after weaning, no differences (P > .10) were observed in ADG or ADFI. Pigs fed diets containing 18% crystalline lactose or 21% deproteinized whey had a higher (P < .05) gain:feed ratio (G/F) than did pigs fed diets containing 25% dried whey or 12.5% dried whey and 9% lactose. In addition, pigs fed diets containing 21% deproteinized whey had increased G/F compared to pigs fed the diet containing 10.9% deproteinized whey and 12.5% dried whey. In Exp. 2, 344 pigs (initially 4.4 kg and 14 +/- 2 d of age) were fed dietary treatments based on four sources of crystalline lactose replacing the lactose provided by dried whey in the positive control diet (20% dried whey). In addition, a negative control diet was formulated with 7.2% crystalline lactose. Casein was used to replace the lysine provided by dried whey. From d 0 to 14 after weaning, no differences (P > . 10) were observed in performance. However, pigs initially fed the positive control diet subsequently (d 14 to 28) consumed more feed than pigs fed the negative control diet. These results indicate that edible-grade deproteinized whey and crystalline lactose can replace the lactose provided by high-quality dried whey without affecting pig performance.

Eastern equine encephalomyelitis virus infection in swine.

In 1 of 2 outbreaks of eastern equine encephalomyelitis virus (EEEV) infection in swine, 280 of 350 pigs died. Histopathologic findings in the brain were typical of EEEV infection. In addition, multifocal necrosis and inflammation were seen in the myocardium. Follow-up investigation in 1 of the herds revealed antibody response to EEEV in surviving pigs and in adult swine. Growth retardation was noticed in surviving pigs. Histologic examination revealed mild lesions in the brain of the survivors.