Effects of different levels of feed intake during four short periods of gestation and housing systems on sows and litter performance.

The current study investigated the effects of different levels of feed intake during 4 short periods of gestation and of housing systems on sow and litter performance. A total of 255 multiparous sows were allotted to 1-4 dietary treatments using a randomized complete block design blocking by initial body weight (BW), backfat (BF) and parity. Sows were housed either in individual stalls (n=129) or group pens (n=126) with 55 sows in each pen with electronic sow feeder during gestation. All sows were fed one common corn-soybean meal-based diet with the amount of 1.0×maintenance energy level of feed intake (106×BW0.75) throughout gestation except 4 periods of 7 d when dietary treatments were imposed on day 27, 55, 83 and 97 of gestation. During the 4 periods, sows were fed 1 of 4 different levels of feed intake: 0.5, 1.0, 1.5 and 2.0×maintenance energy level (0.5M, 1.0M, 1.5M and 2.0M, respectively). Results showed that both BW gain and BF change during gestation for sows on 1.5M (49.7kg and 3.1mm, respectively) and 2.0M (52.5kg and 3.7mm, respectively) levels of feed intake were significantly (P<0.01) greater than sows on 0.5M (26.1kg and -0.1mm, respectively) and 1.0M (35.6kg and 0.1, respectively) levels of feed intake. In contrast, lactation weight gain for sows on 1.5M (3.3kg) and 2.0M (3.4kg) levels of feed intake during 4 short periods of gestation were significantly (P<0.01) less than sows on 0.5M (18.4kg) and 1.0M (11.4kg) levels of feed intake during 4 short periods of gestation, whereas BF loss during lactation for sows on 1.5M (-3.6mm) level of feed intake during 4 short periods of gestation were significantly (P=0.03) higher than sows on 1.0M (-2.1mm) level of feed intake during 4 short periods of gestation. Additionally, average daily feed intake during lactation for sows on 0.5M (6.6kg/d) level of feed intake during gestation tended (P=0.06) to be greater than sows on 2.0M (5.9kg/d) level of feed intake. There were no differences (P>0.1) among 4 levels of feed intake in terms of numbers of total born and weaning piglets. However, both piglet weight at birth (1.46, 1.52, 1.53 and 1.51kg for piglets from sows on 0.5M, 1.0M, 1.5M and 2.0M levels of feed intake during gestation, respectively) and at weaning (6.37, 6.55, 6.64 and 6.38kg for piglets from sows on 0.5M, 1.0M, 1.5M and 2.0M levels of feed intake during gestation, respectively) were maximized at 1.5M level of feed intake. Sows housed in group pens had greater (P<0.01) net BW gain (24.7 vs. 19.2kg) from day 27 of gestation to weaning compared with sows housed in individual stalls. However, there were no differences (P>0.1) between the 2 housing systems in terms of litter size and piglet weight at birth and at weaning. In conclusion, increasing levels of feed intake during 4 short periods of gestation increased BW and BF gain during gestation and led to less BW gain and more BF loss during lactation. Piglet weight at birth and at weaning was maximized at 1.5M level of feed intake. However, housing systems did not affect reproductive performance. Group pen housing system may be beneficial in terms of increased overall BW gain during gestation and lactation.

Effect of replacing conventional soybean meal with low-oligosaccharide soybean meal on growth performance and carcass characteristics of wean-to-finish pigs1.

A trial was conducted to determine the effect of replacing conventional soybean meal (CSBM) with low-oligosaccharide soybean meal (LOSBM) on growth performance and carcass characteristics of wean-to-finish pigs. A total of 432 crossbred pigs (19 d and 6.6 ± 1.2 kg BW) were blocked by sex and BW and assigned to 1 of 6 dietary treatments: 1) CSBM in all phases and fishmeal and spray-dried plasma protein (FM/SDPP) in phases 1 to 3, 2) CSBM in all phases but with no FM/SDPP, 3) LOSBM and FM/SDPP in phases 1 to 3 and CSBM in phases 4 to 6, 4) LOSBM in phases 1 to 3 and CSBM in phases 4 to 6, 5) LOSBM in phases 1 to 6 and FM/SDPP in phases 1 to 3, and 6) LOSBM in phases 1 to 6. The results showed that pig growth performance (ADG, ADFI, and G:F) during the overall period (phases 1 to 6) and carcass traits (HCW, dressing percentage, fat depth, loin depth, and lean percentage) were not affected ( > 0.05) by dietary treatments. Moreover, replacing CSBM with LOSBM in phases 1 to 3 did not affect early phase growth performance in the absence of FM/SDPP but reduced ( ≤ 0.05) ADFI and increased ( < 0.05) G:F during the nursery period (phases 1 and 2) in the presence of FM/SDPP. In phase 2, LOSBM increased ( < 0.05) blood urea nitrogen in comparison with CSBM. In conclusion, reduction of oligosaccharide by replacing CSBM with LOSBM in the early, late, or entire phase of the wean-to-finish period did not improve growth performance and carcass characteristics of pigs.

Effects of different feeding levels during three short periods of gestation on gilt and litter performance, nutrient digestibility, and energy homeostasis in gilts.

The present study investigated the effects of different feeding levels during 3 short periods of gestation on gilt and litter performance, apparent total tract digestibility (ATTD) of energy and nutrients, and energy homeostasis in gilts. A total of 18 gilts were allotted to 1 of 3 dietary treatments using a completely randomized design. All gilts were fed 1 common corn-soybean meal-based diet with the amount of 1.0 × maintenance energy intake (100 × BW (BW) kcal ME/d) throughout gestation except 3 periods of 7 d when dietary treatments were imposed on d 27, d 55, and d 83 of gestation. During the 3 short periods, gilts were fed 1 of 3 different feeding levels: 0.5, 1.0, and 2.0 × maintenance energy level (0.5M, 1.0M, and 2.0M, respectively). Results showed that gilts on 2.0M feeding level had higher ( < 0.05) weight gain from d 27 to 109 of gestation (37.05 vs. 15.34 kg) and greater ( < 0.05) BW change, average daily gain, and gain to feed ratio during gestation periods 1 (d 27-34) and 3 (d 83-90) when compared with gilts on 0.5M feeding level. No differences ( > 0.10) in litter performance were observed among the 3 feeding levels. Additionally, the slopes of BW change in response to feeding levels in period 1 were 4.32 kg/0.5M change from 0.5M to 1.0M feeding level and 3.72 kg/0.5M change from 1.0M to 2.0M feeding level, respectively. There were quadratic ( < 0.05) effects of feeding levels on ATTD of dry matter and gross energy during periods 1 and 2 (d 55-62). Furthermore, fasting plasma concentrations of acyl ghrelin and nonesterified fatty acid (NEFA) in period 1 were greater ( < 0.01) in gilts on 0.5M feeding level than those on 2.0M feeding level. In conclusion, increasing feeding levels during 3 short periods increased primiparous sow performance during these short periods but did not affect litter performance. ATTD of energy and nutrients, and BW change efficiency were maximized for gilts on 1.0 M feeding level. The data also indicated that sows on the lowest feeding level were exposed to negative energy balance as evidenced by the higher plasma acyl ghrelin and NEFA concentrations.

Effect of replacing conventional soybean meal with low oligosaccharide soybean meal fed to weanling piglets.

An experiment was conducted to investigate the effect of replacing conventional soybean meal (CSBM) with low-oligosaccharide soybean meal (LOSBM) on growth performance, blood urea nitrogen (BUN), intestinal morphology, viscosity of the intestinal contents, and visceral organ weight of weanling pigs. Thirty-two 19-d old individually housed pigs (6.2 ± 0.4 kg BW) were blocked by BW, and randomly assigned from within blocks to 1 of 4 dietary treatments: (1) CSBM with inclusion of fish meal and spray dried plasma protein (CSBM+), (2) CSBM without inclusion of fish meal and spray dried plasma protein (CSBM-), (3) LOSBM with inclusion of fish meal and spray dried plasma protein (LOSBM+), and (4) LOSBM without inclusion of fish meal and spray dried plasma protein (LOSBM-) according to a 2 × 2 factorial arrangement. Pigs were fed the experimental diets ad libitum for 14 d. Average daily gain and ADFI were not affected ( > 0.05) by the dietary treatments. However, inclusion of fish meal and spray dried plasma protein improved ( = 0.04) the gain to feed ratio. Replacing CSBM with LOSBM reduced ( = 0.01) viscosity of the intestinal contents. Dietary treatments had no effect ( > 0.05) on the small intestinal length and weights of organs including the pancreas, liver, heart, kidney, and spleen. No differences ( > 0.05) were observed between dietary treatments in villus height, crypt depth, and the ratio of villus height to crypt depth in the ileum, and crypt depth and the ratio of villus height to crypt depth in the jejunum; however, jejunal villus height was reduced ( = 0.02) when replacing CSBM with LOSBM. Concentration of BUN was higher ( = 0.01) for pigs fed the LOSBM diets compared with pigs fed the diets containing CSBM. In conclusion, LOSBM reduced the intestinal digesta viscosity but had no effects on growth performance and intestinal morphology when fed to piglets during the first 2 wk after weaning.

Effect of different feeding levels during three short periods of gestation on sow and litter performance over two reproductive cycles.

The present study investigated the effects of different feeding levels during 3 short periods of gestation on sow and litter performance and its impact on subsequent reproductive performance. A total of 160 multiparous sows were allotted to 1 of 4 dietary treatments using a randomized complete block design with initial body weight (BW) and backfat (BF) as the blocking criteria. All sows were fed one common corn-soybean meal-based diet with the amount of 1.0×maintenance energy intake (100×BW0.75kcalME/d) throughout gestation except 3 periods of 7 d when dietary treatments were imposed on d 27, d 55 and d 83 of gestation. During the 3 short periods, sows were fed 1 of 4 different feeding levels: 0.5, 1.0, 1.5 and 2.0×maintenance energy level (0.5M, 1.0M, 1.5M and 2.0M, respectively). Results showed that both BW gain (16.12, 24.74, 30.62 and 36.71kg, respectively) and BF change (-0.27, 0.99, 1.49 and 2.45mm, respectively) from d 27 to 109 of gestation increased linearly (P<0.01) with the increase of gestation feeding levels. In contrast, with the rise of gestation feeding levels, lactation BW gain (14.31, 9.84, 7.09 and 3.50kg, respectively) decreased linearly (P<0.01), while BF loss during lactation (-0.79, -0.92, -1.12 and -1.57mm, respectively) increased linearly (P=0.05). Additionally, average daily feed intake during lactation (7.05, 7.00, 6.91 and 6.52kg, respectively) tended to decrease linearly (P=0.09) in response to the increase of gestation feeding levels. Furthermore, piglet birth weights increased linearly (P<0.01) with the increase of gestation feeding levels, while piglet weaning weights were similar (P>0.10) among treatments. Subsequent reproductive performance was not affected (P>0.10) by feeding levels during the previous reproductive cycle. In conclusion, increasing feeding levels during 3 short periods of gestation increased BW and BF gains during gestation and caused less BW gain and more BF loss during lactation due to the reduction of lactation feed intake in response to increasing gestation feeding levels. Increasing feeding levels during 3 short periods of gestation increased piglet birth weight, but did not affect piglet weaning weight. The feeding strategies in the current reproductive cycle did not impact subsequent reproductive performance. It was estimated that requirements of 1.20M, 0.66M and 0.65M feeding levels were needed to maintain a constant BW during d 27-34, d 55-62 and d 83-90 of gestation, respectively, indicating current maintenance energy requirement may underestimate the actual maintenance energy requirement in the early gestation, but overestimate the actual maintenance energy requirement in the mid and late gestation.

Plasma acyl ghrelin and nonesterified fatty acids are the best predictors for hunger status in pregnant gilts.

Sows are usually restricted fed during pregnancy to maximize their reproductive efficiency, which may predispose sows to a state of hunger. However, an objective measurement of hunger status has not been established. In the present study, we examined the correlation of plasma hormones and NEFA and selected the best predictors for hunger status using pregnant gilts. Three different levels of feed intake (0.5, 1.0 and 2.0 × maintenance energy intake [0.5M, 1.0M and 2.0M, respectively]) were imposed from Day 28 to 34 of gestation to create different hunger statuses in pregnant gilts. Plasma hormones related to energy homeostasis and NEFA were analyzed to quantify their response to different levels of feed intake. A total of 18 gilts (197.53 ± 6.41 kg) were allotted to 1 of 3 dietary treatments using a completely randomized design. Results showed that BW change, ADG, and G:F from Day 28 to 34 of gestation were higher ( < 0.01) for gilts on the 2.0M feeding level than for gilts on the 0.5M feeding level. Plasma acyl ghrelin concentrations showed a relatively flat pattern during the 24-h period. Plasma acyl ghrelin and NEFA concentrations and areas under the curve (AUC) were greater ( < 0.05) in gilts on the 0.5M level of feed intake than in those on the 2.0M level of feed intake. No differences were observed among the 3 feeding levels in terms of plasma glucagon-like peptide 1 and leptin concentrations. Additionally, consumption time for 1.82 kg feed on Day 35 of gestation was longer ( < 0.01) in gilts fed the 2.0M level of feed intake from Day 28 to 34 of gestation than in those on the 0.5M level of feed intake. Simple linear regression results showed that the AUC of acyl ghrelin was the best predictor for consumption time ( = 0.82), whereas the AUC of NEFA was the best predictor for BW ( = 0.55) or backfat change ( = 0.42) from Day 28 to 34 of gestation. In conclusion, our data suggested that a relative flat pattern existed in pregnant gilts in terms of the diurnal plasma profile of acyl ghrelin and that the level of feed intake of pregnant gilts was negatively correlated with plasma concentrations of acyl ghrelin and NEFA, which, in turn, were negatively associated with feed consumption time. The AUC of acyl ghrelin and NEFA seemed to be the best predictors for hunger status of pregnant gilts.

Effects of dietary tryptophan:lysine ratio on the reproductive performance of primiparous and multiparous lactating sows.

The objective of this study was to determine the effects of dietary tryptophan (Trp) to lysine (Lys) ratio on the performance of lactating sows. Thirty primiparous and 195 multiparous lactating sows (Landrace×Yorkshire) were allocated on the basis of parity, body weight, and backfat to 5 dietary treatments according to a randomized complete block design with 5 blocks of farrowing date. The 5 experimental diets contained 0.16%, 0.19%, 0.23%, 0.26%, or 0.29% standardized ileal digestible (SID) Trp and SID Lys level was identical (0.87%) for all diets, with the Trp:Lys ratio being 0.18, 0.22, 0.26, 0.30, and 0.33, respectively. Sows received their assigned lactation diets from day 109 of gestation to weaning. Litter size was standardized to 10-12 piglets within 2 days after farrowing. The average lactation length was 19 days and no creep feed was provided. Changes of sow body weight and backfat during lactation, weaning-to-estrus interval, litter size and weight, litter weight gain, preweaning piglet mortality, and performance of subsequent parity (total born alive, stillborns, and mummies) were recorded. A quadratic pattern of body weight loss (P=0.046), backfat loss (P=0.067), and average daily feed intake (P=0.096) with increasing Trp level was observed for the primiparous sows during lactation, and the losses were minimized with the SID Trp:Lys ratio of 0.25 (0.22% SID Trp) and average feed intake was maximized with the SID Trp:Lys ratio of 0.22 (0.19% SID Trp) according to a segmented regression analysis model. Nevertheless, preweaning piglet mortality of the primiparous sows increased linearly and quadratically (P<0.001) as Trp level increased. On the contrary, piglet mortality of the multiparous sows decreased linearly (P=0.031) with increasing dietary Trp and the mortality was noticeably reduced when the SID Trp:Lys ratio reached 0.26 (0.23% SID Trp). Furthermore, stillborn piglet numbers of multiparous sows in the subsequent parity decreased linearly (P=0.035) with increasing level of Trp. Other parameters were not significantly (P>0.05) influenced by the dietary treatment. In conclusion, our results indicate that the optimal Trp:Lys ratio for lactating sows is between 0.22 and 0.26.

Effect of feeding peroxidized dried distillers grains with solubles to sows and progeny on growth performance and metabolic oxidative status of nursery pigs.

This experiment evaluated the effects of including peroxidized corn dried distillers grains with solubles (DDGS) in diets for sows and nursery pigs on growth performance, vitamin E (VE), and Se status, and the incidence of mulberry heart disease (MHD) of nursery pigs. Sows (n = 12) were fed corn-soybean meal diets (C-SBM) or C-SBM diets with DDGS (40% and 20% in gestation and lactation, respectively) for 3 parities. In the third parity, 108 weaned pigs (BW = 6.6 ± 0.36 kg) were blocked by BW within litter, assigned to pens (2 pigs/pen; 5 and 4 pens per litter for groups 1 and 2, respectively), and pens were assigned 1 of 3 nursery diets: 1) corn-soybean meal (CON), 2) 30% peroxidized DDGS (Ox-D), and 3) 30% Ox-D with 5 × NRC (1998) level of VE (Ox-D+5VE) for 7 wk, in a 2 × 3 factorial arrangement of sow and nursery diets (n = 9 pens/treatment). The peroxidized DDGS source in nursery diets contained concentrations of thiobarbituric acid reactive substances (TBARS) and peroxide values that were 25 and 27 times greater than a reference corn sample. Sow colostrum, milk, and serum, as well as pig serum and liver samples, were analyzed for α-tocopherol and Se concentrations. Pig serum was analyzed for glutathione peroxidase activity (GPx), TBARS, and sulfur-containing AA (SAA). Pig hearts were evaluated for gross and histopathological lesions indicative of MHD, but none were detected. Pigs from sows fed DDGS tended to have reduced (P = 0.07) VE in serum during lactation and reduced VE at weaning (P < 0.01; 5.6 vs. 6.7 ± 0.1 µg/mL) compared with pigs from sows fed C-SBM. Inclusion of DDGS in sow diets reduced the VE status of pigs during lactation, but not in the nursery when MHD can be a concern. Pigs fed Ox-D+5VE (P = 0.08) tended to have, and those fed Ox-D (P = 0.04) had greater ADFI than pigs fed CON, but ADG was not affected (P > 0.1) by nursery diet. Feeding Ox-D or Ox-D+5VE increased (P < 0.05) serum α-tocopherol compared with CON (2.5, 2.8, and 3.4 ± 0.09 µg/mL, respectively), but TBARS and GPx were not affected by nursery diet. Serum concentration of SAA was 40% to 50% greater (P < 0.01) for pigs fed Ox-D or Ox-D+5VE compared with those fed C-SBM, which was likely due to greater (P < 0.01) SAA intake for pigs fed Ox-D. The antioxidant properties of SAA may have spared VE and Se and masked any effect of Ox-D on metabolic oxidation status. Therefore, increasing the dietary VE concentration was unnecessary in nursery diets containing Ox-D.

Effects of adding supplemental tallow to diets containing distillers dried grains with solubles on fatty acid digestibility in growing pigs.

An experiment was conducted to measure the apparent ileal digestibility (AID) and apparent total tract digestibility (ATTD) of fatty acids in diets containing 0 or 30% corn distillers dried grains with solubles (DDGS) and 0, 5, or 10% tallow. Barrows (n = 24; initial BW = 25 kg) were surgically fitted with a T-cannula at the distal ileum. Pigs (n = 4/diet) were randomly assigned to diets: corn-soybean meal control (CON), CON plus 5% tallow (5T0D), CON plus 10% tallow (10T0D), CON plus 30% DDGS (0T30D), CON plus 5% tallow and 30% DDGS (5T30D), and CON plus 10% tallow and 30% DDGS (10T30D). Eight replicates per treatment were achieved by randomizing diets among pigs for a second collection period. Each pig was fed their respective diet for a 5-d adaptation period followed by 3-d fecal collection and 2-d ileal digesta collection periods. The AID and ATTD of fatty acids was calculated using the index method and acid-insoluble ash as an indigestible marker. When tallow was added to diets with 0% DDGS, there was no effect on AID of palmitic acid (C16:0) or SFA, while AID of stearic acid (C18:0) was increased (66.87% for CON, 72.06% for 5T0D, and 76.81% for 10T0D; P < 0.01). However, when diets contained 30% DDGS, the AID of all SFA was reduced as levels of tallow increased C16:0 (77.62% for 0T30D, 69.66% for 5T30D, and 68.43% for 10T30D), C18:0 (85.87% for 0T30D, 64.08% for 5T30D, and 61.25% for 10T30D), and SFA (79.88% for 0T30D, 68.23% for 5T30D, and 66.29% for 10T30D). The AID of MUFA was not affected when tallow was added to diets with 30% DDGS but actually increased in 5T0D and 10T0D. The amount of apparent ileal digested fatty acids increased with the addition of DDGS and tallow regardless of their digestibility. Amounts of ileal digested MUFA and PUFA increased when both DDGS (P < 0.01) and tallow (P < 0.01) were included in the diet compared to when either ingredient was excluded. For ileal digestible SFA, an interaction (P < 0.01) between DDGS and tallow was observed. Interactions between DDGS and tallow were observed for ATTD of all fatty acids (P < 0.01), except for linoleic acid and PUFA, which were not affected by dietary treatment. The amount of ileal digestible PUFA increased with tallow addition independent from the inclusion level of DDGS and it was a function the dietary concentration of the fatty acid. Adding tallow to corn-soybean based diets increased the amount of digested SFA, but in diets with DDGS, the increment in amount of ileal digestible SFA was less prominent due to lesser digestibility of SFA.

Effects of adding supplemental tallow to diets containing 30% distillers dried grains with solubles on growth performance, carcass characteristics, and pork fat quality in growing-finishing pigs.

Crossbred pigs (n = 315) were blocked by initial BW (6.8 ± 1.1 kg) and randomly assigned to 1 of 4 dietary treatments to evaluate the effects of dietary inclusion of tallow and corn distillers dried grains with solubles (DDGS) on pig growth, carcass traits, and pork fat quality. Diets consisted of a corn-soybean meal control diet (CON) and another 3 corn-soybean meal diets containing 5% tallow (T), 30% DDGS (D), or 5% tallow plus 30% DDGS (TD) in a 2 × 2 factorial arrangement of treatments. Diets were formulated to contain similar levels of available P and standardized ileal digestible Lys:ME among treatments. Pigs were housed in 40 pens, with 7 to 8 pigs per pen, to provide 10 replicates per treatment. Overall ADG did not differ among treatments. Compared with CON (2.76 kg/d) and T (2.59 kg/d), feeding 30% DDGS reduced the ADFI (interaction, P > 0.05) of pigs when fed with 5% tallow (2.45 kg/d for TD) but not when fed alone (2.76 kg/d for D). There was no effect of DDGS on overall G:F, but pigs fed diets with tallow had greater (P < 0.01) G:F (0.4) than pigs fed no tallow (0.37). Feeding tallow increased (P < 0.01) HCW, carcass yield, and backfat depth of pigs independent of DDGS. Feeding DDGS reduced (P < 0.01) belly firmness, as measured by belly flop angle, independent of tallow (D = 71.8° and TD = 57.7° vs. CON = 134.0° and T = 113.4°) and tallow also tended to reduce belly firmness (P < 0.10). Feeding DDGS and tallow reduced the concentration of SFA in belly fat, while the concentration of MUFA were increased (P < 0.01) by feeding tallow but not DDGS. Conversely, feeding DDGS increased (P < 0.01) the concentration of PUFA in belly fat but there was no effect of tallow. An interaction (P = 0.03) between DDGS and tallow for iodine value (IV) of belly fat was observed, in which addition of tallow or DDGS increased the IV of belly fat (64.22 for T and 71.22 for D vs. 59.01 for CON) but addition of both reduced IV (67.88 for TD). The IV of belly fat and backfat were correlated (P < 0.01) with the IV product of the diet fed in phase 3 (r = 0.49 and r = 0.81, respectively). In conclusion, adding 5% tallow to 30% DDGS diets improved G:F and carcass yield while reducing the IV of belly fat. However, pork fat firmness as measured by belly flop angle was not improved.

Interactive effects of distillers dried grains with solubles and housing system on reproductive performance and longevity of sows over three reproductive cycles.

An experiment was conducted to evaluate the interactive effects of dietary distillers dried grains with solubles (DDGS) in sow diets and housing systems on reproductive performance and longevity. Sows (311 for parity 0 and 90 for parity 1) were assigned randomly within parity to 1 of 4 treatments and maintained on these treatments for up to 3 reproductive cycles. Sows were fed either fortified corn-soybean meal control diets (CON) during gestation and lactation or diets containing 40% DDGS in gestation and 20% DDGS in lactation and were housed either in individual stalls or group pens with electronic sow feeders during gestation. Sows fed DDGS had smaller (P < 0.05) litter size (born alive, 11.0 vs. 11.6; weaning, 9.8 vs. 10.2) and had more (P < 0.05) stillborns (0.9 vs. 0.7) than sows fed CON. Litters nursing sows fed DDGS gained less weight (P < 0.01) than litters nursing sows fed CON (47.8 vs. 49.8 kg, respectively). Group-housed sows tended to farrow smaller litters (born alive, 11.0 vs. 11.5; P < 0.10) and had fewer pigs at weaning (9.9 vs. 10.2; P < 0.05) compared with stall-housed sows. Litters from group-housed sows tended (P < 0.10) to gain less weight while suckling than those from stall-housed sows (48.3 vs. 49.4 kg, respectively). Diet did not affect the percentage of sows that completed each successive reproductive cycle. Stall housing tended to increase (P = 0.06) the completion rate of sows at the second reproductive cycle (80.0 vs. 68.2%) and increased (P < 0.05) the completion rate of sows in the third reproductive cycle (68.9 vs. 55.8%) compared with group housing. Sows fed DDGS produced fewer (P < 0.05) live-born pigs (26.2 vs. 27.4) and tended (P < 0.10) to have fewer pigs weaned (23.7 vs. 24.5) over 3 reproductive cycles compared with sows fed CON. Stall-housed sows farrowed more (P < 0.05) total pigs (30.1 vs. 26.7) and live pigs (28.4 vs. 25.2) and had more weaned pigs (25.2 vs. 23.1) compared with group-housed sows over 3 reproductive cycles. In conclusion, long-term feeding of DDGS decreased litter size and sow productivity but did not affect sow longevity. Long-term housing of sows in group pens decreased litter size, sow longevity, and sow productivity. The detrimental effects of housing pregnant sows in pens were most notable when sows were fed corn-soybean meal-based diets compared with DDGS diets.

Dietary lipid sources and levels for weanling pigs.

Collaborative studies comprising growth performance and metabolism experiments were conducted to reevaluate growth performance and nutrient and energy utilization responses of nursery pigs to dietary lipid sources and levels. Two lipid sources (soybean oil or tallow) were included at the rate of 1%, 3%, or 5% at the expense of cornstarch in a 2 × 3 factorial arrangement for 6 diets, and Lys was added to maintain a constant calorie:Lys ratio. A growth performance experiment (d 0 to 7, d 7 to 21, and d 21 to 35 postweaning) involving a total of 822 crossbred pigs was conducted at 9 research stations. Each station contributed 2 to 7 replicate pens with 4 to 6 pigs per pen, resulting in a total of 28 replicate pens per diet. The initial BW ranged from 5.9 to 7.3 kg, and the final BW ranged from 20.9 to 28.9 kg. Diets fed during d 7 to 21 and d 21 to 35 were evaluated with 120 barrows in 2 metabolism experiments with 10 individually fed barrows per diet to determine digestibility and retention of nutrients and energy. Lipid source and the interaction between lipid level and source did not affect growth performance. Lipid did not affect growth performance from d 0 to 7. There was a quadratic decrease (P < 0.05) in ADG with increasing level of added lipid only during d 7 to 21 postweaning. The ADFI was decreased (P < 0.01) both during d 7 to 21 and d 21 to 35 postweaning with increasing level of lipid supplementation. A linear improvement (P < 0.001) in G:F with increasing level of lipid supplementation occurred during both d 21 to 35 and d 0 to 35 postweaning. There was a linear increase in DE, ME, and nitrogen-corrected ME (MEn) of diets fed during d 7 to 21 postweaning with increasing lipid level regardless of lipid source. For diets fed during d 21 to 35 postweaning, there were interactions (P < 0.05) between lipid source and level for digestibility of DM, N, lipid, and energy and for DE, ME, and MEn of diets. The improved feed efficiency was, perhaps, partly attributable to the increase in ME content of the diets with added lipids. There were interactions (P < 0.05) between lipid source and level for efficiency of energy use for BW gain for diets fed during d 21 to 35. The efficiencies of use of DE, ME, and NE for BW gain were not affected in pigs fed diets containing increasing levels of soybean oil; however, there were linear increases in these response criteria for pigs fed diets containing increasing levels of tallow. These results indicate that the energy values of soybean oil from the 2012 NRC study used in formulating these diets were fairly accurate.

Effects of abrupt introduction and removal of high and low digestibility corn distillers dried grains with solubles from the diet on growth performance and carcass characteristics of growing-finishing pigs.

Two experiments were conducted to evaluate the effects of feeding continuously a diet containing 40% dried distillers grains with solubles (DDGS) or intermittently diets containing 20 or 40% DDGS on growth performance and carcass quality of pigs. Responses of the pigs to abrupt introduction and removal of dietary DDGS with differing concentrations of standardized ileal digestible (SID) AA were also evaluated. In Exp. 1, crossbred pigs (n=216; initial BW=51.3±3.1 kg) were assigned randomly to 1 of 4 treatments, which included a corn-soybean meal control (CON), a 20% DDGS diet (D20), a switch between D20 and CON (D20-CON), and a switch between a 40% DDGS diet and CON (D40-CON) with 6 pens per treatment. Pigs abruptly introduced and removed from a 20% DDGS diet (D20-CON) exhibited no differences in growth performance or carcass quality compared with CON pigs. However, intermittently feeding a 40% DDGS diet (D40-CON) resulted in lighter HCW (P<0.05) compared with all other treatments. In Exp. 2, crossbred pigs (n=324; initial BW=33.2±3.0 kg) were assigned randomly to 1 of 6 treatments, including a corn-soybean meal control (CON), a 40% low SID AA DDGS diet (LD), a 40% high SID AA DDGS diet (HD), LD and CON diets alternated (LD-CON), HD and CON diets alternated (HD-CON), or HD and LD diets alternated (HD-LD) with 6 pens per treatment. Final BW and ADG were less (P<0.05) for LD and HD-LD pigs compared with CON pigs, but HD pigs tended to have reduced (P<0.10) final BW and ADG. Loin muscle area was smaller for LD and HD-LD pigs compared with CON pigs (P<0.05). Percentage carcass lean was not affected by dietary treatment. Backfat of DDGS-fed pigs was more unsaturated than CON pigs, but AA digestibility of DDGS did not affect this response. Digestibility of AA in DDGS can influence pig performance and carcass quality when fed at high concentrations (40% or more). The use of a high SID AA DDGS source may diminish some of the negative responses observed for growth performance and carcass characteristics when feeding high concentrations of DDGS if accurate values of SID AA are used in diet formulation. Periodic inclusion and removal of 40% DDGS from diets did not adversely affect growth performance or carcass quality regardless of the SID AA digestibility of the DDGS used. These results indicate that it is possible to abruptly incorporate and remove DDGS from grower-finisher swine diets without meaningful detrimental effects on growth performance or carcass quality.

Impact of distillers dried grains with solubles particle size on nutrient digestibility, DE and ME content, and flowability in diets for growing pigs.

A study was conducted to determine the effect of particle size of distillers dried grains with solubles (DDGS) on DE and ME content, diet DM, energy, N, P digestibility, and diet flowability for growing pigs. One DDGS source was processed through an Urshel Commitrol mill or a hammer mill to achieve mean particle sizes of 818, 595, and 308 µm. The basal control diet consisted of 96.8% corn with supplemental minerals and vitamins. Three experimental diets were formulated by replacing 30% of corn from the basal diet with DDGS of different particle sizes. Thirty-six growing pigs (initial BW of 40 ± 1.13 kg) were assigned to 1 of 4 treatments in a randomized complete block design according to their BW block and housed in individual metabolic crates for a 9-d adaptation period followed by a 4-d total collection of feces and urine. Pigs were provided ad libitum access to water and fed an amount of their respective experimental diets equivalent to 3% of the initial BW of each pig. Feed, feces, and urine samples were analyzed for DM, GE, N, and P and used to calculate diet apparent total tract digestibility (ATTD). Gross energy was also used to calculate DE and ME of diets as well as the DE and ME content of corn and DDGS with different particle sizes. Diet drained and poured angles of repose were measured using a modified Hele-Shaw cell method to evaluate the diet flowability. Inclusion of 30% DDGS with an average particle size of 308 µm improved (P < 0.05) dietary ATTD of DM and GE as well as DE (4,006 vs. 3,783 kcal/kg DM) and ME (3,861 vs. 3,583 kcal/kg DM) compared with 818 µm DDGS. No differences (P > 0.05) were found in N and P digestibility among the 3 DDGS diets. The DDGS particle size of 595 µm had greater (P < 0.05) DE but not ME compared with 818 µm DDGS, and DE and ME were not different between 308 and 595 µm. Compared with a 595 or 818 µm DDGS, grinding DDGS to 308 µm reduced diet flowability as indicated by a greater (P < 0.05) drained angle of repose. These results suggested that for each 25 µm decrease in DDGS particle size from 818 µm to 308 µm, the ME contribution of DDGS to the diet is 13.46 kcal/kg DM, but diet flowability will be reduced.

Assessment of energy content of low-solubles corn distillers dried grains and effects on growth performance, carcass characteristics, and pork fat quality in growing-finishing pigs.

Two studies were conducted to assess the energy content of low-solubles distillers dried grains (LS-DDG) and their effects on growth performance, carcass characteristics, and pork fat quality in grow-finish pigs. In Exp. 1, 24 barrows (Yorkshire-Landrace × Duroc; 80 to 90 d of age) in 2 successive periods were assigned to 1 of 6 dietary treatments. In individual metabolism stalls, pigs were fed a corn-soybean meal diet (control); control replaced by 30, 40, or 50% LS-DDG; or control replaced by 30 or 40% distillers dried grains with solubles (DDGS) at 3% of their initial BW for 12 d. All diets contained 0.25% CrO(2). During the 5-d collection period, feces and urine were collected from each pig. Feed, feces, and urine were analyzed for DM, GE, and N concentrations, and feed and feces were analyzed for Cr content. The ME content of LS-DDG (2,959 ± 100 kcal/kg of DM) was similar to that determined for DDGS (2,964 ± 81 kcal/kg of DM). In Exp. 2, 216 Yorkshire-Landrace × Duroc pigs were blocked by initial BW (18.8 ± 0.76 kg) and assigned to 1 of 24 pens (9 pigs/pen). Pens within block were allotted to 1 of 3 dietary treatments (8 pens/treatment) in a 4-phase feeding program: a corn-soybean meal control (control), control containing 20% LS-DDG, or control containing 20% DDGS. Treatment had no effect on final BW, ADG, ADFI, or HCW. Pigs fed LS-DDG had similar G:F (0.367) compared with pigs fed DDGS (0.370), but tended (P = 0.09) to have decreased G:F compared with pigs fed the control (0.380; pooled SEM = 0.004). Dressing percent was less (P < 0.01) for pigs fed LS-DDG (72.8%) and DDGS (72.8%) compared with the control (73.8%; pooled SEM = 0.22). Pigs fed LS-DDG (54.8%) had greater (P = 0.02) carcass lean compared with pigs fed DDGS (53.4%), but were similar to pigs fed control (54.1%; pooled SEM = 0.33). Bellies from pigs fed DDGS (12.9°) were softer (P < 0.01) than those from pigs fed control (17.7°; pooled SEM = 1.07) as determined by the belly flop angle test. Feeding LS-DDG (14.1°) tended (P < 0.10) to create softer bellies compared with control-fed pigs. The PUFA content of belly fat was reduced (P < 0.01) by LS-DDG (14.0%) compared with DDGS (15.4%), but was increased (P < 0.05) compared with pigs fed the control (9.4%; pooled SEM = 0.34). In conclusion, LS-DDG and DDGS had similar ME values and inclusion of 20% LS-DDG in diets for growing-finishing pigs supports ADG and ADFI similar to that of diets containing 20% DDGS, and may reduce negative effects on pork fat compared with DDGS.

Corn distillers dried grains with solubles in diets for growing-finishing pigs: a cooperative study.

An experiment involving 560 crossbred pigs (28 replications of 4 to 6 pigs per pen) was conducted at 9 research stations to assess the effects of dietary concentrations of corn distillers dried grains with solubles (DDGS) on pig performance and belly firmness. Fortified corn-soybean meal diets containing 0, 15, 30, or 45% DDGS were fed in 3 phases from 33 to 121 kg of BW. A common source of DDGS containing 90.1% DM, 26.3% CP, 0.96% Lys, 0.18% Trp, 9.4% crude fat, 34.6% NDF, 0.03% Ca, and 0.86% P was used at each station. Diets were formulated to contain 0.83, 0.70, and 0.58% standardized ileal digestible (SID) Lys during the 3 phases with diets changed at 60 and 91 kg of BW, respectively. The DDGS replaced corn and soybean meal, and up to 0.172% Lys and 0.041% Trp were added to maintain constant SID concentrations of Lys and Trp in each phase. At each station, 2 pigs from each pen in 2 replications were killed and a midline backfat core was obtained for fatty acid analysis and iodine value. In most instances, there were differences among stations (P < 0.01), but the station × treatment interactions were few. Body weight gain was linearly reduced in pigs fed the greater amounts of DDGS (0 to 45%) during phase I (950, 964, 921, and 920 g/d; P < 0.01) and over the entire experimental period (944, 953, 924, and 915 g/d; P = 0.03), but ADFI (2.73, 2.76, 2.68, and 2.70 kg) and G:F (347, 347, 345, and 341 g/kg) were not affected (P = 0.15 and P = 0.33, respectively) during the entire test. Backfat depth was reduced (linear, P < 0.02) by increasing amounts of DDGS (22.5, 22.7, 21.4, and 21.6 mm), but LM area (47.4, 47.4, 46.1, and 45.4 cm(2)) was not affected (P = 0.16) by treatments. Estimated carcass fat-free lean was 51.9, 52.2, 52.4, and 52.1% for 0 to 45% DDGS, respectively (linear, P = 0.06). Flex measures obtained at 6 stations indicated less firm bellies as dietary DDGS increased (lateral flex: 11.9, 8.6, 8.4, and 6.6 cm; linear, P < 0.001; vertical flex: 26.1, 27.4, 28.2, and 28.7 cm; linear, P < 0.003). Saturated and monounsaturated fatty acid concentrations in subcutaneous fat decreased linearly (P < 0.001) and PUFA concentrations increased linearly (P < 0.001) with increasing DDGS in the diet. Iodine values in inner (61.1, 68.2, 74.7, and 82.2) and outer (67.9, 73.6, 79.6, and 85.8) backfat increased linearly (P < 0.001) as DDGS in the diet increased. In this study, feeding diets with 30 or 45% DDGS did not have major effects on growth performance, but resulted in softer bellies. Regression analysis indicated that iodine values increased 4.3 units for every 10 percentage unit inclusion of DDGS in the diet.

Effect of cross-fostering on transfer of maternal immunity to Mycoplasma hyopneumoniae to piglets.

The aim of this study was to assess the effect of cross-fostering on transfer of maternal Mycoplasma hyopneumoniae-specific humoral and cell-mediated immunity (CMI) from gilts to piglets. Cross-fostering, carried out within gilt pairs, was based on the gilts' M hyopneumoniae vaccination status in accordance with the following scheme: six pairs of vaccinated gilt × non-vaccinated gilt (V × N); five pairs of non-vaccinated gilt × vaccinated gilt (N × V); and five pairs of vaccinated gilt × vaccinated gilt (V × V). The piglets were cross-fostered at 0, six, 12 or 20 hours after birth. Two piglets per gilt per time point were cross-fostered (that is, eight piglets per gilt were moved) and the remaining piglets served as non-cross-fostered controls. In addition, four litters served as non-cross-fostered controls. A maximum of 10 piglets per gilt were sampled. The piglets' M hyopneumoniae-specific humoral immunity was assessed by ELISA and their CMI was assessed by delayed-type hypersensitivity testing. M hyopneumoniae-specific antibodies were detected in non-cross-fostered piglets from vaccinated dams and from piglets cross-fostered within the V × N gilt pair at six hours or more, and within the V × V gilt pair at all time points. Piglets cross-fostered within the N × V gilt pair had detectable M hyopneumoniae-specific antibodies only if they had been moved within six hours of birth. The transfer of M hyopneumoniae-specific CMI to piglets appeared to be source-dependent, and was detected only in piglets maintained on their vaccinated dams for at least 12 hours after birth.

Effect of dietary supplementation of oregano essential oils to sows on colostrum and milk composition, growth pattern and immune status of suckling pigs.

This study evaluated the effects of supplementing sow diets with oregano essential oils (OEO) during gestation and lactation on sow colostrum and milk composition and on the growth pattern and immune status of suckling pigs. A total of 70 second-parity sows were randomly assigned to 1 of 2 gestation dietary treatments within 24 h after service: control (CON) or CON + 250 mg/kg of OEO (OREG). In lactation, sows were again assigned to either the CON or OREG dietary treatment. Thus, the lactation treatments were CON-CON, CON-OREG, OREG-CON, and OREG-OREG. Colostrum and blood samples were collected from 6 sows per lactation dietary treatment. Thymus lymphocyte (T lymphocyte) subpopulations (γδ, cluster of differentiation 8, and 32 cluster of differentiation 4) were enumerated in blood and mammary secretions along with IGF-1, IgG, and IgA concentrations. Piglet growth rate were determined from 18, 17, 17, and 18 litters from the CON-CON, CON-OREG, OREG-CON, and OREG-OREG lactation dietary treatments, respectively. Growth rates were determined in 630 piglets, and piglets were individually identified and weighed on 1, 5, 9, 12, 16, and 19 d of age. Oregano essential oil supplementation during gestation or lactation had no effect (P > 0.05) on GE, CP, GE:CP, GE:fat, and IGF-1 in sow milk. Reductions of the fat percentage in milk on d 7 (P < 0.05) and d 14 (P = 0.07) were found in sows supplemented with OEO during lactation compared with those in the CON treatment. Milk from sows supplemented with OEO during lactation had the greatest number of T lymphocytes compared with those in the lactation CON treatment on d 14 of lactation (P < 0.01). The number of T lymphocytes in milk was greater for sows in the CON-OREG treatment compared with those other treatments on d 14 of lactation (P < 0.05). Energy intake was greater on d 1 to 5 in piglets from sows fed OEO during gestation than those from sows in the CON treatment (P < 0.05). A trend (P = 0.10) for greater milk intake was observed in piglets from sows supplemented with OEO during gestation compared with those from sows in the CON treatment. Similarly, a tendency for an increase in ADG on d 1 to 5 was found in piglets from sows supplemented with OEO during gestation compared with those from sows in the CON treatment (P = 0.10). Insulin-like growth factor-1 at birth and on d 7 and 14 of lactation did not differ among piglets from sows assigned to the different dietary treatments. Oregano essential oil supplementation of sow diets did not affect (P > 0.05) immunoglobulin concentrations in piglets after suckling. Supplementing sow diets with OEO during gestation or lactation did not affect (P > 0.05) the T lymphocytes, percentage of T-lymphocyte subpopulations, and natural killer cell activity of piglets during lactation. Supplementing sow diets with 250 mg/kg of OEO during gestation and lactation did not affect the growth potential of and immune responses in suckling piglets.

Effects of tryptophan supplementation on aggression among group-housed gestating sows.

The objective of this study was to determine the effects of dietary Trp supplementation on mixing-induced aggression and the associated stress, and on reproductive performance in gestating sows. After weaning, sows were mixed in pens with electronic sow feeders on concrete-slatted floors. Each pen housed 21 ± 2.8 sows, with approximately 2.7 ± 0.43 m(2)/sow of floor space allowance. Multiparous sows (n = 168) from 8 breeding groups were used, with 4 groups assigned to a control diet and 4 groups assigned to a high-Trp diet. Control sows received corn- and soybean meal-based diets throughout gestation (0.15% Trp) and lactation (0.21% Trp). Three days before and after mixing, sows assigned to the high-Trp treatment received approximately 2.3 times the dietary Trp (0.35% in the gestation diet and 0.48% in the lactation diet) fed to control sows. Six focal sows (2 sows from each of parity 1, 2, and 3 or greater) in each pen were designated and videotaped for 72 h after mixing to determine the type and number of aggressive interactions among sows. Before and 48 h after mixing, saliva samples were collected from focal sows, and scratches were assessed on all sows. Data were analyzed using the FREQ and GLIMMIX procedures (SAS Inst. Inc., Cary, NC). Aggression among sows was intense during the initial 6 h and decreased between 6 and 72 h after mixing. The initial aggression caused scratches and increased cortisol concentrations (P < 0.05). Mature sows tended to fight for longer periods (112 vs. 52 s/h per sow, SE = 23.8; P < 0.10) but had fewer scratches caused by aggression (injury score = 4.3 vs. 6.5, SE = 1.13; P < 0.01) than parity-1 sows. Supplementation of dietary Trp reduced the total duration of head-to-head knocking (P < 0.05) but did not affect other aggressive behaviors. There was no difference between dietary treatments in injury scores or saliva cortisol concentrations. Sows in the high-Trp treatment had more total piglets born (12.5 vs. 10.5 pigs/litter, SE = 0.55; P < 0.05) and more stillborn piglets (1.5 vs. 0.8 pigs/litter, SE = 0.20; P < 0.05), but had no significant change (P = 0.12) in piglets born alive (10.8 vs. 9.7 pigs/litter, SE = 0.42) compared with control sows. The results indicate that the initial aggression after mixing caused more injuries in young sows than in mature sows. Supplementation of dietary Trp at 2.3 times the control amount for a short period did not effectively reduce aggression and the associated stress in sows at mixing.

Dietary effects of distillers dried grains with solubles on performance and milk composition of lactating sows.

A study was conducted to evaluate the dietary effect of adding increasing concentrations of distillers dried grains with solubles (DDGS) to corn- and soybean meal-based sow lactation diets on sow and litter performance, energy and N digestibility, plasma urea N (PUN), and milk fat and protein concentrations. Mixed-parity sows [n = 307; 221 ± 15 kg of BW, 4.54 parities, litter size of 10.6, and litter weight at birth (alive) of 15.14 kg] were assigned randomly to 1 of 5 dietary treatments: control (CON; corn-soybean meal); 10, 20, and 30% DDGS; and 30% DDGS high-protein (HP) diets. Sows were moved to farrowing rooms on d 109 of gestation and were fed the dietary treatments until weaning. Within each treatment group, feces and urine for energy and N digestibility analysis (from d 10 to 12 of lactation) and blood for PUN analysis and milk fat and protein concentrations (on d 0 and 19 of lactation) were collected from 6 randomly chosen parity 3 to 5 sows. There were no dietary effects (P = 0.10) of DDGS on ADFI of sows and sow backfat change. However, sows fed 30% DDGS HP lost more BW compared with sows fed CON (P < 0.05). There were no dietary effects (P = 0.71) of DDGS on preweaning mortality of piglets, litter weight gain, and piglet ADG. Dietary treatments did not affect (P > 0.05) DE, ME, N retention, or N digestibility of the diets. There were no differences in the concentrations of fat and protein in milk at weaning (d 19) among dietary treatments. Sows fed 20 and 30% DDGS had less (P < 0.05) PUN at weaning (d 19) than sows fed CON and 30% DDGS HP. Inclusion of up to 30% DDGS in a lactation diet did not affect (P > 0.05) sow and litter performance, DE and ME contents of the diets, N retention and digestibility, and milk composition compared with sows fed a corn-soybean meal CON diet. It was concluded that addition of up to 30% DDGS in a lactation diet will support satisfactory sow and litter performance.