Effects of L-carnitine fed during gestation and lactation on sow and litter performance

Multiparous sows (n = 307) were used to evaluate the effects of added dietary L-carnitine, 100 mg/d during gestation and 50 ppm during lactation, on sow and litter performance. Treatments were arranged as a 2 (gestation or lactation) x2 (with or without L-carnitine) factorial. Control sows were fed 1.81 kg/d of a gestation diet containing .65% total lysine. Treated sows were fed 1.59 kg/d of the control diet with a .23 kg/d topdressing of the control diet that provided 100 mg/d of added L-carnitine. Lactation diets were formulated to contain 1.0% total lysine with or without 50 ppm of added L-carnitine. Sows fed 100 mg/d of added L-carnitine had increased IGF-I concentration on d 60 (71.3 vs. 38.0 ng/mL, P<.01) and 90 of gestation (33.0 vs. 25.0 ng/mL, P = .04). Sows fed added L-carnitine had increased BW gain (55.3 vs 46.3 kg; P<.01) and last rib fat depth gain (2.6 vs. 1.6 mm; P = .04) during gestation. Feeding 100 mg/d of added L-carnitine in gestation increased both total litter (15.5 vs. 14.6 kg; P = .04) and pig (1.53 vs 1.49 kg; P<.01) birth weight. No differences were observed in pig birth weight variation. Added L-carnitine fed during gestation increased litter weaning weight (45.0 vs. 41.3 kg, P = .02); however, no effect of feeding L-carnitine during lactation was observed. No differences were observed in subsequent days to estrus or farrowing rate. Compared to the control diet, feeding added L-carnitine in either gestation, lactation, or both, increased (P<.05) the subsequent number of pigs born alive, but not total born. In conclusion, feeding L-carnitine throughout gestation increased sow body weight and last rib fat depth gain and increased litter weights at birth and weaning.     

Effects of a novel carbohydrate and protein source on sow performance during lactation

Ninety-one primiparous and multiparous sows and their pigs were used to evaluate the effects of a novel carbohydrate- and protein-based feed ingredient (Nutri-Pal, NP) on sow and litter performance during lactation. Nutri-Pal is a feed supplement for sows that consists of a blend of milk chocolate, brewer's yeast, whey products, and glucooligosaccharides. The dietary treatments consisted of a corn-soybean meal control and a corn-soybean meal plus 5% NP fed from d 110 of gestation to weaning. The diets were formulated to be equal in total Lys and ME. Sows were allotted to treatment based on parity, body weight, and the date of d 110 of gestation. There were 46 and 45 sows per treatment over four farrowing groups. Litters were standardized to 10 pigs and weighed within 1 d of farrowing, and all sows weaned at least 8 pigs at an average age of 21 d. Sows were weighed on d 110 of gestation, d 1 postfarrowing, and at weaning. Sows were fed three times daily during lactation. Sows were checked twice daily after weaning for signs of estrus. The weaning weight of sows fed NP was increased (P < 0.10) compared with those fed the control diet. Sows fed the control diet tended (P = 0.11) to lose more weight per day from d 110 of gestation to weaning than the sows fed NP. Otherwise, sow response variables (sow weight on d 110 of gestation and d 1 postfarrowing, d 110 of gestation to d 1 postfarrowing and lactation weight change per day, d 110 of gestation to d 1 postfarrowing, lactation, and total feed intake, days to estrus, pigs born alive or dead, and litter and average pig birth weight) were not affected (P > 0.10) by diet. There were no effects (P > 0.10) of diet on litter performance response variables (pigs weaned, litter and average pig weaning weight and gain, and survival percent). The NP feed ingredient had minor effects on sow productivity, but it did not affect litter productivity indices.     

Efficacy of sucrose and milk chocolate product or dried porcine solubles to increase feed intake and improve performance of lactating sows

Two experiments were conducted to determine the voluntary feed intake and performance of lactating sows fed diets containing a sucrose/milk chocolate product (MCP) blend (Exp. 1) or dried porcine solubles (DPS; Exp. 2). Dried porcine solubles is a coproduct of heparin extraction from porcine small intestines. In Exp. 1, mixed-parity sows (n = 108) at two research centers were assigned to a corn-soybean-meal-based diet formulated to contain 0.9% total lysine or a similar diet that contained 4% sucrose and 2% MCP on an as-fed basis. Sows were allowed ad libitum access to dietary treatments from the day of farrowing until pigs were weaned at approximately 21 d postpartum. Diet had no significant effect on voluntary feed intake of sows during lactation, backfat depth, or postweaning interval to estrus, but it had variable effects on body weight changes. Inclusion of the sucrose/MCP blend in diets elicited a 2% improvement in litter weaning weight at one research center and a 6% depression in litter weaning weight at the other center (diet x research center, P < 0.05). Litter size throughout lactation was unaffected by dietary treatment. In Exp. 2, mixed-parity sows (n = 119) at two research centers were assigned to corn-soybean meal-based diets formulated to contain 0.9% total lysine with 0, 1.5, or 3.0% added DPS. Sows were assigned to dietary treatments within research center, farrowing group, and parity at parturition. Dried porcine solubles tended to increase (P < 0.10) total feed consumed in the first 9 d of lactation and average daily feed intake over the entire lactation (6.03, 6.53, and 6.30 kg) for sows fed 0, 1.5, and 3.0% DPS, respectively. Litter size and weight on d 18 of lactation were not affected by concentration of DPS in the diet. Days from weaning to estrus and percentage of sows displaying estrus were not influenced by diet. We conclude that inclusion of the sucrose/MCP blend in the diet for lactating sows had no consistent effect on voluntary feed intake of sows and weight gain of nursing pigs. Inclusion of DPS at 1.5 or 3.0% tended to improve feed intake of lactating sows but had no significant influence on litter performance.     

The addition of ground wheat straw as a fiber source in the gestation diet of sows and the effect on sow and litter performance for three successive parities

A regional experiment was conducted at 8 experiment stations, with a total of 320 sows initially, to evaluate the efficacy of adding 13.35% ground wheat straw to a corn-soybean meal gestation diet for 3 successive gestation-lactation (reproductive) cycles compared with sows fed a control diet without straw. A total of 708 litters were farrowed over 3 reproductive cycles. The basal gestation diet intake averaged 1.95 kg daily for both treatments, plus 0.30 kg of straw daily for sows fed the diet containing ground wheat straw (total intake of 2.25 kg/d). During lactation, all sows on both gestation treatments were fed ad libitum the standard lactation diet used at each station. Response criteria were sow farrowing and rebreeding percentages, culling factors and culling rate, weaning-to-estrus interval, sow BW and backfat measurements at several time points, and litter size and total litter weight at birth and weaning. Averaged over 3 reproductive cycles, sows fed the diet containing wheat straw farrowed and weaned 0.51 more pigs per litter (P 相似文献   

Response of sows and litters to added dietary biotin in environmentally regulated facilities

A 3-yr study was conducted to evaluate the effects of biotin on sow longevity, reproductive performance and piglet performance to weaning utilizing 161 sows and 414 litters. Sows and gilts were fed a basal corn-soybean meal diet (without any antibiotic or chemotherapeutic compounds) during gestation and lactation containing either 0 or .55 ppm added biotin. The basal diet contained .17 ppm total dietary biotin based on microbiological assay. Results indicated sow culling rates and weight gains, number of live pigs at birth, pig weights at birth and weaning, and the interval from weaning to rebreeding were similar for both treatment groups. However, sows fed the diet with added biotin weaned more (P less than .05) pigs/litter overall and at gestation-lactation period 1 than did sows fed the basal diet without added biotin, although biotin did not increase (P greater than .10) the number of pigs weaned at gestation-lactation periods 2 through 5. The incidence of dermatitis, hair loss and soundness of feet and legs did not appear to be affected by adding biotin to the diet. Thus, the addition of .55 ppm biotin to a corn-soybean meal diet fed during gestation and lactation did not improve any of the criteria measured except number of pigs weaned overall.     

Effects of dietary valine concentration on lactational performance of sows nursing large litters. NCR-42 Committe on Swine Nutrition

A cooperative study, using 231 primiand multiparous crossbred sows from six experiment stations (IN, KS, MI, MN, ND, and OH), was conducted to determine the effects of elevating dietary valine concentration in corn-soybean meal diets on lactational performance of sows nursing large litters. Crossbred sows were fed diets containing a minimum of .60% lysine during gestation. Sows were allotted at farrowing to four dietary valine concentrations, .80, .95, 1.10, and 1.25%. Crystalline L-valine replaced cornstarch to maintain a constant ratio of corn:soybean meal across diets. Dietary lysine, provided by corn, soybean meal, and .15% crystalline L-lysine x HCl, was .90% in all diets. Sows were allowed ad libitum access to feed. Sows were weighed within 24 h after farrowing, and all litters were adjusted to > or = 10 pigs/litter by d 2 following farrowing. Average sow parity, number of pigs on d 2, and lactation length for the four treatments were, respectively, 2.3, 2.3, 2.3, 2.5; 10.9, 10.8, 10.8, 10.7; and 25.1, 24.5, 25.2, 25.0 d. The ADFI during lactation was 5.87, 5.77, 5.87, and 5.74 kg (P > .50); hence, valine intakes were 41, 48, 55, and 61 g/d (linear, P < .01). Lysine intake ranged from 51.5 to 52.7 g/d (P > .50). Sow weight after farrowing averaged 198 kg (P > .60). Overall pig survival to weaning was high (>92%), and the number of pigs weaned (10.1, 10.3, 10.3, 10.3) did not differ (P > .30) among treatments. Litter weaning weights (73.6, 73.6, 74.5, 72.6 kg), litter weight gains (55.1, 55.1, 56.0, 54.1 kg), sow weight change during lactation (-4.9, -5.4, -4.8, -6.3 kg), and return-to-estrus interval (7.5, 6.4, 6.9, 8.2 d) were not affected (P > .30) by dietary valine. There were no station x treatment interactions (P > .50). These results indicate no benefit of elevated dietary valine for lactating sows nursing > or = 10 pigs and consuming a corn-soybean meal diet containing .90% lysine and .80% valine.     

Effect of Lactation Diet Fat Level on Sow and Litter Performance

The primary objective of this study was to determine the effects of supplemental dietary fat during lactation on sow BW, sow backfat thickness, sow feed consumption, litter size, and pig growth rate. Dietary treatments included 0, 3, 6, and 9% supplemental low acid yellow fat in a traditional corn-soybean meal basal lactation diet. A total of 160 Landrace and crossbred sows (approximately 40 per treatment) were included in the study. Sows fed 3 and 6% supplemental fat had greater (P<0.10) average backfat thickness at weaning. Sow weight change and feed consumption were inconsistent among dietary fat levels. Dietary fat level during lactation did not affect number of pigs born alive or number of stillborns. However, the 9% fat level was associated with more mummified pigs at birth. Number of pigs weaned was greater for the 0% supplemental fat than for the 9% fat level. The largest average pig weights at 21 (5.8±0.29 kg) and 28 (7.48±0.38) d of age were those from sows fed the 3% added fat diet. Sows with ≤25.4 mm backfat at farrowing had more pigs born alive (P<0.05), had less backfat at 21 and 28 d of lactation (P<0.05), and consumed more feed during wk 2 and 3 of lactation. Of all sows fed the control diet, sows with >25.4 mm backfat at farrowing consistently had heavier pigs throughout the lactation phase (P<0.05). Backfat loss during lactation was lower (P<0.05) for sows with ≤25.4 mm at farrowing within all dietary treatments. Consistent significant differences were not observed in sow weight loss or feed consumption between low and high backfat sows for each dietary treatment. Sow backfat loss during lactation is dependent on body condition at farrowing, in that, fatter sows at farrowing have greater backfat loss during lactation. Sows with ≤25.4 mm of backfat at farrowing responded to added dietary fat treatments and produced heavier pigs throughout the lactation period.     

Recombinant porcine somatotropin for sows during late gestation and throughout lactation.

Two experiments were conducted to evaluate whether administration of recombinant porcine somatotropin (pST) to sows (Hampshire-Yorkshire) enhanced lactational performance. In Exp. 1, sows (n = 84) were fed a corn-soybean meal diet (17.8% CP), or a similar diet with 8% added fat, from d 108 of gestation to d 28 of lactation. Half of the sows fed each diet were injected with 6 mg/d of pST from d 108 of gestation to d 24 of lactation. Diets were fed at 2.27 kg/d from d 108 of gestation until farrowing and then were self-fed during lactation. By d 3 of lactation, litter size was standardized at 8 to 10 pigs per litter. Treating sows with pST resulted in a 10-fold increase (P less than .001) in serum somatotropin at 4 h postinjection. Serum glucose was increased (P less than .01) and serum triglycerides, creatinine, and urea N were decreased (P less than .01) by pST. During the summer, apparent heat stress occurred in pST-treated sows, resulting in 14 deaths. Most (10) of the deaths occurred just before, during, or shortly after farrowing. Fewer (P less than .08) deaths occurred when pST-treated sows were fed the diet with added fat. Sows treated with pST consumed less feed (P less than .10) and lost more backfat (P less than .10) during lactation than controls. Increasing the dietary fat did not prevent these changes. Weaning weights of pigs and milk yield of sows (estimated by deuterium oxide dilution) were not affected by pST treatment. In Exp. 2, sows (n = 42) were injected weekly with 0 or 70 mg of pST on d 3, 10, 17, and 24 of lactation. Litters were standardized by d 3 at 8 to 10 pigs, and sows were fed the same control (low fat) diet as in Exp. 1. Sows treated with pST consumed less feed and lost more weight and backfat during lactation than untreated sows. Litter size, average pig weaning weights, and milk yield were not influenced by pST treatment. These data indicate that a 6-mg daily injection of pST from 6 d prepartum to d 24 of lactation or a 70-mg weekly injection of pST from 3 d postpartum to d 24 of lactation does not increase milk production in lactating sows.     

Effects of salinomycin on sow weight change during lactation and on sow reproductive performance

Forty-five gravid cross-bred sows (mean parity 3.3 +/- .3) were randomly allotted to two dietary treatments: corn-soybean mean (CS) or CS plus 60 mg salinomycin per kilogram of diet (CSS). Sows were fed their respective diets through two successive parities with dietary treatment initiated at 100 d postcoitum and continued until weaning of the second successive litter. Therefore, sows fed CSS received salinomycin for 14 d before the first parturition and for approximately 153 d before the second parturition. Daily feed intake was restricted to 2 kg.hd-1.d-1 during gestation and to 3 kg.hd-1.d-1 from weaning to breeding. All sows. had ad libitum access to feed during lactation. Sows were weighed 7 d prior to parturition, at weaning and at breeding. Weaning-to-estrus interval and farrowing interval were recorded for all sows. Litters were weighed at birth and weaning. There were no differences (P greater than .05) between dietary treatments in sow weights before parturition, at weaning or at breeding for either first or second farrowing. The CSS-fed sows lost more weight from weaning to breeding after the first (P less than .03) and second (P less than .05) lactation periods than CS-fed sows. The CSS-fed sows tended to gain more (P = .06) weight during lactation than CS-fed sows. There were no differences (P greater than .05) between treatments in lactation feed intake, weaning-to-estrus interval, farrowing interval, litter size born or weaned, litter weights at birth or at weaning, or in sow culling rate.(ABSTRACT TRUNCATED AT 250 WORDS)     

Effect of feather meal as a source of valine for lactating sows

An experiment was conducted to evaluate feather meal as a source of Val in lactating sow diets. Sows (five farrowing groups; mean parity = 2.34) were allotted to one of two dietary treatments on the basis of ancestry, parity, and weight and date of d 110 of gestation. The treatment diets included 1) corn-soybean meal lactation diet (n = 40) or 2) corn-soybean meal lactation diet with 2.5% feather meal (n = 39). The diets were formulated on an equal Lys basis. All litters were adjusted to 10 pigs within 24 h after farrowing, and all sows weaned at least nine pigs. Sows were bled at 110 d of gestation and at weaning, and serum urea N was determined. Backfat thickness was determined ultrasonically at 110 d of gestation and at weaning. Serum urea N and backfat thickness at d 110 of gestation were used as covariates for serum urea N and backfat thickness at weaning, respectively. The litter response criteria (weaning weight, litter weight gain, and percentage survival) were not affected (P > .10) by feather meal. The sow response criteria (weaning weight, weight loss per day, weaning backfat thickness, change in backfat thickness, ADFI, and days to estrus) were not affected (P > .10) by feather meal. Sows fed feather meal had increased (P < .01) serum urea N and tended (P = .15) to have decreased sow weaning weight. Following the initial analysis of the data, the data set was split into two groups: 1) sows with litters gaining less than 2.17 kg/d (n = 19 and 20 for control and feather meal diets, respectively) and 2) sows with litters gaining more than 2.17 kg/d (n = 21 and 19 for control and feather meal diets, respectively). These two groups were analyzed separately. In sows with litters gaining less than 2.17 kg/d, the litter and sow criteria were not affected (P > .10) by treatment. In sows with litters gaining more than 2.17 kg/d, sow weaning weight was decreased (P < .04) and sow weight loss (P < .02) and serum urea N (P < .01) were increased in sows fed feather meal. Feather meal (as a source of Val) did not improve litter weight gain, but it increased serum urea N.     

Effects of additional feed during late gestation on reproductive performance of sows: a cooperative study

A cooperative research study involving 1,080 litters was conducted at eight stations to determine the effects of additional feed during the last 23 d of gestation on reproductive performance of sows and on preweaning performance of their pigs. Primiparous and multiparous sows were fed fortified corn- or sorghum-soybean meal diets (14% crude protein). Control sows received 1.82 kg/d from March through November and 2.27 kg/d from December through February. Treated sows were fed an additional 1.36 kg of feed/d from d 90 of gestation to farrowing. Sows were allowed to consume the same diet ad libitum during a 21-d lactation. Additional feed in late gestation resulted in greater (P less than .001) sow weight gain from d 90 to d 110 of gestation (16.8 vs 9.0 kg) and greater (P less than .001) parturition-lactation weight loss (21.3 vs 16.4 kg). Total weight gain from breeding to 21 d of lactation favored sows that received extra feed (27.5 vs 22.7 kg; P less than .001). Sows receiving extra feed had more live pigs at farrowing (10.05 vs 9.71, P = .06) and at 21 d postpartum (8.35 vs 8.06, P = .09), and the pigs were heavier at birth (1.48 vs 1.44 kg, P = .003) and at 21 d (5.37 vs 5.20 kg, P = .006). Lactation feed intake and number of days from weaning to estrus were not affected by treatment. The results indicate that additional feed in late gestation improves reproductive performance in sows. In this study, the cost of an additional 31 kg of feed/sow was more than offset by the value of the additional sow weight gain (approximately 5 kg), the additional .3 of a pig/litter at weaning and the additional 2.6 kg of total litter weaning weight.     

Lactation feed disappearance and weaning to estrus interval for sows fed spray-dried plasma

Four experiments involving 265, 410, 894, and 554 sows (Exp. 1 to 4, respectively) were conducted to determine the effect of spray-dried plasma (SDP) at 0 or 0.25% (Exp. 1 and 2) and 0 or 0.50% (Exp. 3 and 4) in lactation diets on average daily feed disappearance (FD), sum of sow BW, fetal and placental loss from d 110 gestation to weaning (SWL), litter size at weaning, litter weight at weaning, and average days from weaning to first estrus (WEI). Experiments 1, 3, and 4 were conducted during summer months, and Exp. 2 was conducted during fall to winter months. Experiment 1 used only parity 1 and parity 2 sows and Exp. 4 used only mature (>2 parities) sows, whereas Exp. 2 and 3 used all parity groups. Sows fed SDP in Exp. 1 had increased (P < 0.01) FD and a tendency for reduced (P = 0.06) SWL and WEI (P = 0.06). Sows fed SDP in Exp. 2 had a tendency for increased (P = 0.09) sow BW at weaning and reduced (P = 0.09) SWL, whereas other variables were not different between diets. Parity 1 and 2 sows fed SDP in Exp. 3 had increased (P < 0.01) FD, but mature sows fed SDP had reduced (P = 0.02) FD. Pig survival and litter size at weaning for all parity groups was not different between diets. The WEI for parity 1 sows fed SDP was reduced (P = 0.02) and tended to be reduced (P = 0.10) for mature sows fed SDP, but was not different between diets for parity 2 sows. More parity 1 sows fed SDP were detected (P = 0.01) in estrus 4 to 6 d after weaning, and fewer were detected (P < 0.01) in estrus 6 d after weaning compared with control parity 1 sows. In Exp. 4, FD was reduced (P < 0.01) for mature sows fed SDP; however, litter weight and average pig BW at weaning was increased (P < 0.01) with more (P < 0.01) marketable pigs (pig BW > 3.6 kg) weaned per litter. Relatively low dietary levels of SDP (0.25 to 0.50%) fed to parity 1 sows farrowed during summer months increased lactation FD and reduced WEI. Mature sows fed SDP during summer months consumed less lactation feed without compromising WEI, but had an increased litter weight, average pig BW, and number of marketable pigs at weaning.     

Utilization of distillers dried grains with solubles and phytase in sow lactation diets to meet the phosphorus requirement of the sow and reduce fecal phosphorus concentration

Two experiments were completed to determine the potential for using distillers dried grains with solubles (DDGS) in diets with or without phytase to provide available P, energy, and protein to highly productive lactating sows without increasing their fecal P. In Exp. 1, the dietary treatments were as follows: (1) corn and soybean meal with 5% beet pulp (BP) or (2) corn and soybean meal with 15% DDGS (DDGS). Besides containing similar amounts of fiber, diets were isonitrogenous (21% CP, 1.2% Lys) and isophosphorus (0.8% P). Sixty-one sows were allotted to dietary treatments at approximately 110 d of gestation (when they were placed in farrowing crates) based on genetics, parity, and date of farrowing. Sows were gradually transitioned to their lactation diet. On d 2 of lactation, litters were cross-fostered to achieve 11 pigs/litter. Sows and litters were weighed on d 2 and 18. Fecal grab samples were collected on d 7, 14, and 18 of lactation. Dietary treatment did not affect the number of pigs weaned (10.9 vs. 10.8) or litter weaning weight. On d 14, DDGS sows had less fecal P concentration than BP sows (28.3 vs. 32.8 mg/g; P = 0.04). Fecal Ca of sows fed DDGS decreased for d 7, 14, and 18 (55.6, 51.4, and 47.1 mg/g of DM, respectively; P = 0.05) but not for BP sows. In Exp. 2, the dietary treatments were as follows: (1) corn and soybean meal (CON), (2) CON + 500 phytase units of Natuphos/kg diet, as fed (CON + PHY), (3) corn and soybean meal with 15% DDGS and no phytase (DDGS), or (4) DDGS + 500 FTU of Natuphos/kg of diet, as fed (DDGS + PHY). Sows (n = 87) were managed as described for Exp 1. Litter BW gain (46.0, 46.3, 42.1, and 42.2 kg; P = 0.25) and sow BW loss (8.1, 7.2, 7.4, and 6.3 kg for CON, CON + PHY, DDGS, and DDGS + PHY, respectively; P = 0.97) were not affected by dietary treatment. Fecal P concentration did not differ among dietary treatments but was reduced at d 14 and 18 compared with d 7 (P = 0.001). However, fecal phytate P concentration was decreased by the addition of DDGS when DDGS and DDGS + PHY were compared with the CON sows except on d 7 (P < 0.05). Sows fed CON diet had greater fecal phytate P than sows fed DDGS, and sows fed DDGS + PHY had less fecal phytate P than sows fed DDGS with no phytase (P = 0.001). Although these experiments were only carried out for 1 lactation, these results indicate that highly productive sows can sustain lactation performance with reduced fecal phytate P when fed DDGS and phytase in lactation diets.     

Lactational and subsequent reproductive responses of lactating sows to dietary lysine (protein) concentration

Gilts (n = 208) were used to evaluate the effect of lysine (protein) intake over three parities on lactation and subsequent reproductive performance. Sows were assigned randomly to one of five experimental diets at each farrowing. The five corn-soybean mealbased lactation diets contained increasing concentrations of total lysine (.60, .85, 1.10, 1.35, and 1.60%) and CP (14.67, 18.15, 21.60, 25.26, and 28.82%). Other amino acids were provided at a minimum of 105% of the NRC (1988) ratio to the lysine requirement. Sows had ad libitum access to their assigned diets from parturition until weaning (19.5+/-.2 d postpartum). All sows were fed a common gestation diet (14% CP and .68% lysine) from weaning to next farrowing. Litter size was standardized by d 3 postpartum to 10 pigs in parity 1 and 11 pigs in parity 2 and 3. Increasing dietary lysine (protein) linearly decreased (P<.05) voluntary feed intake of parity 1 (from 5.4 to 4.6 kg/d), 2 (from 6.5 to 5.8 kg/d), and 3 sows (from 6.8 to 6.2 kg/d). With the increase of dietary lysine (protein) concentration during lactation, litter weight gain responded quadratically (P<.05) in all three parities. Maximal litter ADG was 2.06, 2.36, and 2.49 kg/d in parities 1, 2, and 3, respectively, which occurred at about 44, 55, and 56 g/d of lysine intake for parity 1, 2, and 3 sows, respectively. Increasing dietary lysine (protein) had no effect (P>.1) on sow weight change, weaning-to-estrus interval, and farrowing rate in all three parities and no effect on backfat change in parity 2 and 3, but tended to increase backfat loss linearly (P<.1) in parity 1. A linear decrease of second litter size (total born, from 11.7 to 10.1, P<.1; born alive, from 11.0 to 8.9, P<.01) was observed when dietary lysine (protein) increased during the first lactation. Lysine (protein) intake during the second lactation had a quadratic effect on third litter size (P<.05; total born: 13.3, 11.2, 11.6, 11.9, and 13.6; born alive: 11.8, 10.1, 10.3, 11.2, and 12.4). However, fourth litter size was not influenced by lysine (protein) intake during the third lactation. These results suggest that the lysine (protein) requirement for subsequent reproduction is not higher than that for milk production. Parity influences the lysine (protein) requirement for lactating sows and the response of subsequent litter size to previous lactation lysine (protein) intake.     

Value of raw soybeans and soybean oil supplementation in sow gestation and lactation diets: a cooperative study

A cooperative study using 215 sows during two parities (349 litters) was conducted at six stations to determine the effect of raw soybeans in gestation and lactation diets on sow and litter performance. Sows were bred and allotted to fortified corn diets containing either soybean meal (control) or raw soybeans. A corn-soybean meal-soybean oil diet, isocaloric to the raw soybean diet, was included as a third treatment at three stations. All diets contained 14% CP. These diets were fed during both gestation and lactation through two parities. The daily gestation feed intake ranged from 1.8 to 2.3 kg/sow, depending on station. During lactation, the sows were allowed ad libitum access to their respective diets. Gestational weight gain was not influenced by diet, but sows fed raw soybeans consumed less (P less than .01) feed during lactation and had greater (P less than .01) lactational weight loss and their pigs were lighter in weight (P less than .05) both at 21 d and at weaning (varied between 3 and 5 wk of age). Sows fed the diet with supplemental oil had reproductive and lactational performance similar to those fed the control diet. Milk obtained at d 10 to 14 of lactation from sows fed raw soybeans had lower (P less than .05) protein content than milk from sows fed the other two diets, but fat content of the milk tended to be increased by raw soybeans or by added soybean oil. Return to estrus was not affected by diet.(ABSTRACT TRUNCATED AT 250 WORDS)     

Effect of lactation and rebreeding phase energy intake on primiparous and multiparous sow performance

Fifty-three primiparous sows were used to study the effects of a high-energy, fat-supplemented diet on sow lactation and rebreeding performance. Sows received either a low [Lo, 12.5 Mcal metabolizable energy (ME)/d] or high (Hi, 16.0 Mcal ME/d) energy sorghum-soybean diet during a 28-d lactation. At weaning, sows were randomly allotted, within lactation treatment, to a low (lo, 5.54 Mcal ME/d) or high (hi, 9.61 Mcal ME/d) energy sorghum-soybean diet until the day of first postweaning estrus. Primiparous sows fed Lo weaned larger (P less than .05) litters than sows fed Hi; however, average pig weight was not affected by lactation treatments. Primiparous sows fed Hi had more backfat at weaning (P less than .01) than Lo sows. In contrast, sow weight was not affected by dietary treatments. Neither lactation nor rebreeding treatments influenced days to rebreeding; however, an interaction (P less than .01) was observed. Mean days from weaning to rebreeding for Lolo, Lohi, Hilo and Hihi sows were 10.0, 7.6, 6.9 and 17.1, respectively. Forty sows were maintained on the same dietary treatments during their second parity. Sows receiving Lo during their second parity farrowed and weaned more (P less than .05) pigs than Hi sows. Multiparous sows fed Hi nursed heavier (P less than .05) pigs on d 21 of lactation and at weaning compared with Lo sows. Sows fed Hi were heavier (P less than .05) and had more (P less than .01) backfat at weaning of their second litter compared to Lo sows. Days to postweaning estrus were not affected by lactation or rebreeding diets. Mean length of the second parity rebreeding interval for Lolo, Lohi, Hilo and Hihi sows was 6.2, 10.2, 7.0 and 10.5 d, respectively. These results suggest that feeding levels during lactation of 12.5 Mcal ME/d or higher supported adequate rebreeding performance. Postweaning feeding levels did not influence days to first estrus. Feeding a high energy diet continuously throughout the lactation and rebreeding phases in primiparous sows may lengthen the postweaning interval to estrus.     

Dietary medium- or long-chain triglycerides improve body condition of lean-genotype sows and increase suckling pig growth

In a field trial conducted on a commercial swine farm, lean-genotype sows (n = 485) were fed diets containing 0 or 10% supplemental fat as either medium-chain triglyceride or choice white grease from d 90 of gestation until weaning (15.5 d). Effects on standard sow and litter production traits were examined together with assessment of sow body condition using live ultrasound. Daily feed intake during lactation was 10% higher in sows consuming diets without added fat (7.2 vs 6.5 kg; P < 0.01); however, lactation ME (23.9 Mcal/d) and digestible lysine (54 g/d) intakes were unaffected (P > 0.10). Sows supplemented with fat were 4 kg heavier on d 109 of gestation (220 vs 224 kg; P < or = 0.01), 1 d after farrowing (210 vs 214 kg; P < or = 0.01), and at weaning (210 vs 214 kg; P < or = 0.01). Expressed as overall gain, this amounted to a 23% increase (0.66 vs 0.86 kg/d; P < or = 0.01) and was accompanied by a 49% increase in backfat (0.82 vs 1.68 mm; P < or = 0.03) from d 90 to farrowing. Changes in sow weight (-0.01 kg/d) and backfat (+4.2 mm) over lactation were minimal and were not affected by fat supplementation (P > or = 0.10). Longissimus muscle area at weaning was slightly greater (44.96 vs 46.2 cm2) in sows consuming fat than in control sows (P < or = 0.05), but changes in longissimus muscle area were not significant from d 90 to weaning (P > or = 0.10). Gestation length, pigs born alive, average birth weight, survival (d 3 to weaning), and days to estrus were not affected by diet (P > 0.10). However, supplemental fat increased pig ADG (192 vs 203 g/d; P < 0.01) and average pig weaning weight (4.3 vs 4.5 kg) at 15.5 d (P < or = 0.02). No differences between the two fat sources were detected. This large-scale study demonstrated that supplemental fat during gestation and lactation effectively improved sow condition and improved suckling pig performance without affecting energy intake during lactation, implying improved efficiency of sow energy utilization.     

Effects of dietary salt level during gestation and lactation on reproductive performance of sows: a cooperative study

Two experiments involving 1,020 litters were conducted at eight research stations to determine the effects of dietary NaCl (salt) concentration during gestation and lactation on reproductive performance of sows. Primiparous and multiparous sows were fed fortified corn- or grain sorghum-soybean meal diets at 1.82 kg/d during gestation. During the winter months (December, January, February) the feeding level was increased to 2.27 kg/d. Sows had ad libitum access to diets during lactation. Dietary concentrations of added salt were .50 and .25% in Exp. 1 and .25 and .125% in Exp. 2. When more feed was fed during gestation, the salt concentrations were reduced to .40, .20, .20 and .10%, respectively, in order to maintain a constant daily intake of Na and Cl during gestation. Gestation weight gain and lactation (21-d) weight loss of the sows were not affected by dietary salt level in either experiment. In Exp. 1, lowering the salt concentration did not influence the number of pigs farrowed, but it resulted in a .05 kg/pig reduction (P less than .01) in average birth weight. Average 21-d pig weights also tended (P less than .19) to be lower in the low-salt group. There was a decrease in litter size from the first to the second farrowing for sows fed low salt, but not for sows fed the higher salt concentration. In Exp. 2, reducing the salt content from .25 to .125% did not alter reproductive performance. The overall ratio of males to females at birth in the population of greater than 10(4) pigs was 52.3:47.7. Lower salt intakes tended to reduce the percentage of males born in both experiments, although the differences were not significant (P greater than .3). The results indicate that reducing the salt concentration in sows diets from .50 to .25 or .125% reduces birth weight in newborn pigs. When continued for more than one reproductive cycle, feeding less than .5% salt appears to reduce litter size at birth and weaning.     

Sow litter size is increased in the subsequent parity when lactating sows are fed diets containing n-3 fatty acids from fish oil

Supplementing diets with n-3 fatty acids from fish oil has been shown to improve reproductive performance in dairy cattle and sheep, but there is little published literature on its effects in sows. The aim of this study was to evaluate the reproductive performance of sows fed fish oil as a source of n-3 PUFA prefarrowing and during lactation. From d 107.7 ± 0.1 of pregnancy, 328 sows ranging in parity from 0 to 7 (parity 1.95 ± 0.09, mean ± SE) were fed either a diet containing tallow (control) or an isocaloric diet containing 3 g of fish oil/kg of diet (n-3). Diets were formulated to contain the same amount of DE (13.9 MJ/kg), crude fat (54 g/kg), and CP (174 g/kg). Sows were fed their treatment diet at 3 kg daily for 8 d before farrowing and continued on treatment diets ad libitum until weaning at 18.7 ± 0.1 d of lactation. After weaning, all sows were fed a gestation diet without fish oil until their subsequent farrowing. There was no effect (P > 0.310) of feeding n-3 diets prefarrowing on piglet birth weight, preweaning growth rate, piglet weaning weight, or sow feed intake. However, n-3 sows had a larger subsequent litter size (10.7 ± 0.3 vs. 9.7 ± 0.3 total born; 10.2 ± 0.3 vs. 9.3 ± 0.3 born live; P < 0.05). In conclusion, this is the first study to demonstrate that feeding sows a diet containing n-3 PUFA from fish oil fed before farrowing and during lactation increased litter size in the subsequent parity independent of energy intake.     

The use of feed-grade amino acids in lactating sow diets

Background: The use of feed grade amino acids can reduce the cost of lactation feed. With changing genetics,increasing feed costs, and higher number of pigs weaned with heavier wean weights further evaluation of higher inclusion levels of feed-grade amino acid in lactation diets than previously published is warranted. Two experiments(Exp.) were conducted to determine the optimal inclusion level of L-lysine HCl to be included in swine lactation diets while digestible lysine levels remain constant across dietary treatments and allowing feed grade amino acids to be added to the diet to maintain dietary ratios relative to lysine to maximize litter growth rate and sow reproductive performance. Furthermore, the studies were to evaluate minimal amino acid ratios relative to lysine that allows for optimal litter growth rate and sow reproductive performance.Results: Exp. 1: Increasing L-lysine HCl resulted in similar gilt feed intake, litter, and reproductive performance.Average litter gain from birth to weaning was 2.51, 2.49, 2.59, 2.43, and 2.65 kg/d when gilts were fed 0.00, 0.075,0.150, 0.225, and 0.30% L-lysine HCl, respectively. Exp. 2: The average litter gain from birth to weaning was 2.68,2.73, 2.67, 2.70, and 2.64 kg/d(P 0.70) when sows were fed 0.1, 0.2, 0.3, 0.4, and 0.4% L-lysine HCl plus valine,respectively. No other differences among dietary treatments were observed.Conclusions: Collectively, these studies demonstrate corn-soybean meal based lactation diets formulated with a constant SID lysine content for all parities containing up to 0.40% L-lysine HCl with only supplemental feed grade threonine and a methionine source have no detrimental effect on litter growth rate and subsequent total born.