Performance of sows fed high levels of nonstarch polysaccharides during gestation and lactation over three parities

The effect of feeding sows a starch diet or a diet with a high level of nonstarch polysaccharides (NSP) during gestation, lactation, or both gestation and lactation during the first three parities on reproductive performance, body weight, and backfat was studied. Four-hundred and forty-four postpuberal gilts were allotted to a 2 x 2 x 2 factorial experiment. Treatments were diet composition during gestation (including the weaning-to-estrus interval; G-Starch: 274 g/kg of starch and 123 g/kg of fermentable NSP or G-NSP: 86 g/kg of starch and 300 g/kg of fermentable NSP), diet composition during lactation (L-Starch: 293 g/kg of starch and 113 g/kg of fermentable NSP or L-NSP: 189 g/kg of starch and 216 g/kg of fermentable NSP) and group-housing system during gestation (free access stalls or electronic feeding). Both gestation diets were formulated to be isoenergetic. During lactation, sows were given free access to the lactation diets from d 6 after parturition onwards. Body weight and backfat gains during gestation were lower in sows fed the G-NSP diet than in those fed the G-starch diet (P < 0.001). The effects were more pronounced in the electronic feeding system than in the free access stalls. These results indicate an overestimation of the energy value of fermentable NSP. Body weight and backfat losses during lactation were less in sows fed the G-NSP diet during gestation than in those fed the G-starch diet (P < 0.05),which can be explained by a 0.4 kg/d higher (P < 0.001) feed intake during lactation of the sows fed the G-NSP diet. Sows fed the L-NSP diet lost more backfat during lactation than sows fed the L-starch diet (P < 0.05). The number of total piglets born and live-born piglets was 0.5 piglet higher in sows fed the G-NSP diet than in those fed the G-starch diet (P < 0.05). Lactation diet did not affect the number of total piglets born or live-born piglets. This study shows that, although high NSP diets negatively influence body weight and backfat thickness of the sows, it is possible to feed sows a diet with a high level of fermentable NSP diet during both gestation and lactation without negative effects on reproductive performance. Under the conditions of this study, feeding sows a diet with a high level of fermentable NSP during gestation and a high level of starch during lactation seems the most favorable feeding strategy.     

Effects of additional starch or fat in late-gestating high nonstarch polysaccharide diets on litter performance and glucose tolerance in sows

The effects of feeding additional starch or fat from d 85 of gestation until parturition on litter performance and on glucose tolerance in sows that were fed a diet with a high level of fermentable nonstarch polysaccharides (NSP) were studied. The day after breeding, 141 multiparous sows were assigned to the experiment. At d 85 of gestation, sows were assigned to the treatments. Sows were fed 3.4 kg/d (as-fed basis) of a high-NSP diet or the same quantity of the high-NSP diet and an additional 360 g of starch (from wheat starch) daily, or the same quantity of the high-NSP diet and an additional 164 g of fat (from soybean oil) daily. During lactation, all sows were given free access to the same lactation diet. Approximately 1 wk before the expected time of parturition, an oral glucose tolerance test was performed in 38 randomly chosen sows by feeding pelleted glucose (3 g/kg BW0.75). Blood samples for glucose analyses were taken at -10, 10, 20, 30, 40, 50, 60, 70, 80, 90, 105, and 120 min after glucose was fed. The supply of additional dietary starch or fat did not increase piglet birth weight or total litter weight at birth. Sows that were fed the high-NSP diet had more (P = 0.097) live-born piglets and fewer (P = 0.084) stillborn piglets than did sows that were fed additional fat, whereas sows that were fed additional starch were intermediate for these variables. Piglet mortality after birth was not affected by dietary treatment. Body weight and backfat gains in the last month of gestation were higher for sows fed additional starch or fat than for sows fed the high-NSP diet (P < 0.001 and P = 0.017, respectively). Feed intake in lactation was greatest by sows fed the high-NSP diet, least by sows fed additional starch at the end of gestation, and intermediate by sows fed additional fat (P = 0.099). The differences in lactation feed intake did not result in differences in BW and backfat losses during lactation. Sows that were fed additional fat had the greatest glucose area under the curve (P = 0.044), indicating that these sows were less tolerant to glucose. In conclusion, feeding additional energy (starch or fat) in late-gestating sows that are fed a high-NSP diet did not increase litter weight at birth or piglet survival, but did increase maternal gain. Feeding sows additional energy from fat might induce glucose intolerance, whereas feeding sows additional energy from starch did not induce glucose intolerance.     

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.     

Effects of postweaning dietary energy source on reproductive traits in primiparous sows

An experiment was conducted to study the effects of major dietary energy source fed from weaning to ovulation or from ovulation to d 35 of pregnancy on reproductive traits in primiparous sows. Dietary energy sources were used to manipulate the plasma insulin concentration. One hundred thirteen sows were used in a split-plot design. From weaning to ovulation sows were fed at two times maintenance either a diet with tallow (Fat) or maize starch plus dextrose (Starch) as the major energy source. From ovulation onward, sows within each dietary group were alternately reassigned to either the Fat or the Starch diet and were fed at 1.25 times maintenance. Estrus detection was performed three times a day from d 3 to 9 after weaning and sows were inseminated each day of standing estrus. On d 35 of pregnancy, the sows were slaughtered and their reproductive tracts were removed. Plasma insulin concentration was higher in sows fed the Starch-rich diet than in sows fed the Fat-rich diet on d 4 after weaning (1.30 vs 0.97 ng/mL, P = 0.08) and on d 32 of pregnancy (1.20 vs 0.51 ng/mL, P < 0.001). Plasma glucose and IGF-I concentration on d 4 after weaning and d 32 of pregnancy did not differ between sows on the two dietary energy sources. The percentage of sows exhibiting estrus within 9 d after weaning was 52 and 67% for the Fat and Starch diet before ovulation, respectively (P = 0.11), whereas the weaning-to-estrus interval was 134 vs 123 h, respectively (P = 0.12). Survival analysis showed that sows fed the Fat-rich diet had a 1.6 times higher risk to remain anestrous until d 9 after weaning than sows fed the Starch-rich diet (P = 0.04). No effect of dietary energy source, either before or after ovulation, on uterine, placental, or embryonal development on d 35 of pregnancy was found. It can be concluded that the dietary energy source provided after weaning can affect the risk of sows to remain anestrous but does not affect uterine, placental, or embryonic traits.     

Effects of feeding sows fat or fructose during late gestation and lactation

The effects of dietary fat or fructose supplementation during late gestation and lactation on sow milk production and composition and on progeny were examined. On d 88 of gestation, 24 sows were allotted by parity to three dietary treatments (eight sows/treatment). Treatments were 1) a 12.5% crude protein, corn-soybean meal control, 2) the control + 10% added fat or 3) the control + 23% high fructose corn syrup. All treatments were fed to supply 1.82 kg/d of the control diet from d 89 of gestation to parturition with sows in treatments 2 or 3 receiving .18 kg of additional fat or .53 kg of additional high fructose corn syrup, respectively. Feed was gradually increased from d 1 to 7 of lactation to 4.54 kg/d of the control diet (plus .45 kg of added fat and 1.33 kg of added fructose for treatments 2 and 3) and remained at these levels for the remainder of the 21 d lactation period. All treatments were iso-nitrogenous; treatments 2 and 3 were iso-caloric. Litter birth weights, number of pigs born alive, weaning weights and piglet survival rate were not affected by sow treatment. Stillbirths were less (P less than .05) for sows fed fat. Lipid content of milk 24 h post-farrowing was greater (P less than .05) from sows fed fat compared with sows fed fructose. Milk production estimates indicated that multiparous sows fed fat produced more (P less .05) milk than sows fed the control diet. On d 112 of gestation and d 15 of lactation, serial blood samples were drawn to monitor sow response to a glucose challenge (1 g/kg body weight).(ABSTRACT TRUNCATED AT 250 WORDS)     

Effects of exposure to high ambient temperature and dietary protein level on sow milk production and performance of piglets.

The effects of high ambient temperature and level of dietary heat increment on sow milk production and piglet performance over a 28-d lactation were determined in 59 multiparous crossbred Large White x Landrace pigs kept at a thermoneutral (20 degrees C) or in a hot (29 degrees C) constant ambient temperature. Experimental diets fed during lactation were a control diet (NP; 17.6% CP) and two low-protein diets obtained by reduction of CP level (LP; 14.2% CP) or both reduction of CP and addition of fat (LPF; 15.2% CP); the NE:ME ratio was 74.3, 75.6, and 75.8% for NP, LP, and LPF diets, respectively. All diets provided 0.82 g of digestible lysine/MJ of NE, and ratios between essential AA and lysine were above recommendations. Creep feed was provided after d 21 of lactation. Reduction of CP level did not influence (P > 0.10) milk production, milk composition, or piglet performance. Despite higher nursing frequency (39 vs 34 sucklings per day), milk production decreased (P < 0.01) from 10.43 to 7.35 kg/d when temperature increased from 20 to 29 degrees C. At d 14, DM (18.6 vs 18.1%) and energy (4.96 vs 4.75 MJ/kg) contents in milk tended (P = 0.09) to be higher in sows kept at 29 degrees C. Over the 28-d lactation, piglet BW gain and BW at weaning decreased (P < 0.01) from 272 to 203 g/d and 9.51 to 7.52 kg, respectively, when temperature increased from 20 to 29 degrees C. Daily creep feed intake over the 4th wk of lactation was higher (P < 0.01) at 29 degrees C than at 20 degrees C (388 vs 232 g/litter, respectively), which was reflected in a greater increase in BW gain between wk 1 to 3 and wk 4 at the higher temperature (147 vs 130%); BW gain between weaning and d 14 postweaning was higher (P < 0.05) for piglets originating from sows kept at 29 degrees C (280 vs 218 g/d). In connection with their lower growth rate, DM (31.2 vs 33.0%), protein (15.5 vs 16.0%), lipid (12.3 vs 13.9%), and energy (8.39 vs 9.09 kJ/g) contents in weaned, slaughtered piglets were lower (P < 0.01) at 29 than at 20 degrees C. In conclusion, modification in the CP:NE ratio in order to decrease dietary heat increment did not affect milk production and piglet performance in thermoneutral or hot climatic conditions. Our results confirm the negative effect of high ambient temperatures on milk yield and emphasize the importance of creep feed supply to improve pre- and postweaning growth of piglets in these conditions, especially when weaning occurs after 3 wk of age.     

Energy balances of lactating sows in relation to feeding level and stage of lactation

Twelve crossbred sows were used in an energy balance study to estimate energetic efficiency of milk production from feed. Balances were made from 7 to 14 d and from 18 to 25 d of lactation. Two feeding levels were applied (high and low). The low level (L) was meant to supply energy slightly above maintenance, with energy needed for milk to be derived from body reserves. The high level (H) was meant to supply sufficient energy for maintenance and for milk production. The low-level animals received 2.5 to 2.6 kg of feed/d and the high level animals 4.8 to 6 kg/d. The loss of weight of sows during lactation depended more on feeding level than on stage of lactation. A high level of feeding to sows resulted in heavier piglets compared with the low feeding level (significant after 10 d). At 24 d of age piglets with the high-feeding-level sows weighed 7.5 kg and those with the low-level sows, 5.7 kg. At the high level, animals excreted 1,200 to 2,800 kcal more milk energy per day than the low-level animals. Energy for milk from feed was produced with an efficiency of 67 to 69% with a maintenance requirement of 112 to 125 kcal metabolizable energy (ME) X W-.75 X d-1. Efficiency of milk production from feed was calculated as 62% and the maintenance requirement was 68 kcal. In this calculation, milk was corrected toward zero energy balance. Another way of calculating this efficiency after correcting feed toward zero energy balance resulted in estimates of 68% for efficiency and of 88 kcal ME X W-.75 X d-1 for maintenance requirement. From these data it was derived that, for each piglet, the sow needed to receive .5 to .6 kg of extra feed (ME content 3,000 kcal/kg) per day to cover milk production. Level of metabolic rate for nursing piglets was estimated as 97 kcal ME X W-.75 X d-1 for maintenance and, in addition, .195 kcal/kcal extra of milk intake above maintenance.     

Influence of different phosphorus levels and phytase supplementation in gestation diets on sow performance

A total of 104 sows of different parities were studied. They were fed four diets with different phosphorus (P) levels during gestation for two reproductive cycles, while the same diet was fed during lactation. The aim was to decrease the total P level in the diet during gestation and to evaluate the effect on sow performance. The gestation treatments were low P (LP-; 3.7 g P/kg feed), low P with phytase (LP+, Ronozyme P; 765 FTU/kg feed), medium P (MP; 4.5 g P/kg feed) and high P (HP; 6.0 g P/kg feed). Daily feed allowances were 2.6 kg during gestation and 9.2 kg during lactation. Number of born piglets and piglet mortality were higher (p < 0.05) in the LP treatments than in the MP and HP treatments. No difference (p > 0.05) in the numbers of live-born piglets, piglet birthweights, sow weights or piglet weight gains was found between the treatments. Phosphorus level in sow milk was the highest (p < 0.05) in the MP treatment, while no effects (p > 0.05) of treatment were found on milk Ca levels, P and Ca levels in serum of sows and piglets, nor on the analysed mineral, fat and protein contents of piglets. The estimated average requirement of P for the entire gestation period was 4.4-4.5 g/day. In conclusion, a reduction of dietary total P content during gestation did not result in negative effects on sow or piglet performance. This suggests that it should be possible to lower the dietary P content for gestating sows, compared with earlier recommendations, and thereby reduce the environmental P pollution.     

Effects of dietary fermentable carbohydrates on behavior and heat production in group-housed sows

The effects of dietary nonstarch polysaccharides (NSP) on behavior and heat production in group-housed sows were studied. Twelve groups of six nonpregnant sows were fed one of four experimental diets that were similar in composition except for starch and NSP contents. Exchanging sugar beet pulp silage (SBPS) for tapioca created the difference in dietary starch and NSP ratio. On a dry matter (DM) basis, diets contained 0, 10, 20, or 30% SBPS. Sows were group-housed. Intake of fermentable NSP (fNSP) for diets containing 0, 10, 20, or 30% SBPS averaged 7.06, 9.18, 11.61, and 13.73 g x kg(-0.75) d(-1), respectively. Sows were fed, once a day at 0800. Dry matter intake for diets containing 0, 10, 20, or 30% SBPS, averaged 38.05, 38.38, 38.53, and 38.35 g x kg(-075) x d(-1), respectively, and ME intake averaged 523, 518, 514, and 493 kJ x kg(-0.75) x d(-1), respectively. On average, sows spent 177 min/d on physical activity, of which 8.8% was spent on eating. Time spent in physical activity was affected by diet (P = 0.005). Sows fed 0 or 10% SBPS spent more time on physical activity than sows fed 20 or 30% SBPS (P = 0.002). Energy cost of physical activity averaged 464 kJ x kg(-0.75) x d(-1) (standard estimated mean of 31) and was similar for diets (P = 0.679). Total heat production (HP) and activity-related heat production (AHP) were affected by diet (P < 0.05). Sows tended to be quieter when fNSP intake increased (P = 0.063). The effect of fNSP intake on HP and AHP was not constant during the day. During the night period, fNSP intake did not affect HP and AHP (P > 0.10). During the day period, increased fNSP intake decreased HP (P = 0.006) and tended to decrease AHP (P = 0.062). During eating, increased fNSP intake increased HP (P = 0.012) and tended to increase AHP (P = 0.074). Despite similar DMI, sows fed 0 or 10% SBPS spent less time eating than sows fed 20 or 30% SBPS (P = 0.009). Feed consumption rate was higher (P = 0.003) in groups fed 0 or 10% SBPS than in groups fed 20 or 30% SBPS. Feed consumption rate decreased by 0.19 g DM x kg(-0.75). min(-1) (P = 0.003) for each gram of fNSP intake. The energy saving effect of physical activity on the NE value of fNSP from SBPS ranged between 2.3 and 3.7 kJ/g of fNSP intake. In conclusion, intake of fNSP from SBPS affected energy expenditure for physical activity (P = 0.063); however, this effect was not constant during the day.     

The influence of gestation feeding strategy on body composition of gilts at farrowing and response to dietary protein in a modified lactation

Previous experiments have indicated that reproductive function in lean, modern genotypes may be more dependent on body protein mass than, as previously believed, on body lipid reserves. This was investigated in a 3 x 2 factorial arrangement of treatments, involving 60 first-parity sows, comparing three pregnancy feeding strategies and two lactation diets. During pregnancy, sows were fed either a basal diet (5 g lysine/kg, 13 MJ of DE/kg [C]) or the same quantity of basal diet + energy source [E], or additional basal diet supplying both protein and energy [A]. The level of supplement for E and A was adjusted weekly to achieve a backfat thickness measurement (P2 position) of 28 mm at farrowing. Isoenergetic lactation diets were fed to appetite and provided either high (180 g CP/kg, 9 g lysine/kg [H]) or low lysine (120 g CP/kg, 6 g lysine/kg [L]). From d 21 of lactation, sows were separated from their litters and housed next to a boar for 8 h each day; final weaning occurred on d 31. Pregnancy treatment differences in backfat and weight were achieved, with C sows having less backfat on d 1 of lactation than E and A sows (E = 28.1, A = 28.0, C = 22.7 kg, P < 0.001). Sows fed additional basal diet were heavier than E sows, which were heavier than C sows (E = 190, A = 201, C = 178 kg, P < 0.001). Average feed intake over lactation showed a pregnancy feeding effect, with E sows eating less than A or C sows (E = 4.9, A = 5.2, C = 5.4 kg/d, P < 0.005). Total lactation weight loss was affected by pregnancy feeding (E = 18.0, A = 19.0, C = 8.4 kg, P < 0.05) and by lactation diet (L = 19.0, H = 11.3 kg, P < 0.05), whereas total lactation backfat loss was affected only by pregnancy treatment (E = 6.9, A = 6.5, C = 4.6 mm, P < 0.05). No pregnancy treatment or lactation diet effects were observed for litter performance. Lactation diet affected weaning-to-estrus interval, with more sows on the H diet coming into estrus within 6 d of partial weaning (P < 0.05), but there was no pregnancy treatment effect. Therefore, voluntary feed intake during lactation was suppressed by increased fat reserves at a limited body protein mass but not when body protein mass was also increased. Partial weaning-to-estrus interval was increased by reduced dietary protein.     

Combined yeast culture and organic selenium supplementation during late gestation and lactation improve preweaning piglet performance by enhancing the antioxidant capacity and milk content in nutrient-restricted sows

This study was conducted to investigate the effects of dietary supplementation with yeast culture (YC) and organic selenium (Se) during late gestation and lactation on reproductive performance, milk quality, piglet preweaning performance, antioxidant capacity, and secretion of immunoglobulin in multiparous sows. A total of 160 healthy cross-bred sows (Landrace × Yorkshire, mean parity 4.1 ± 0.3) were randomly assigned to 4 groups as follows: 1) high nutrient (HN), 3,420 kcal/kg digestible energy (DE) and 18.0% crude protein (CP); 2) low nutrient (LN), 3,240 kcal/kg DE and 16.0% CP; 3) LN + YC, LN diet + 10 g/kg YC; 4) LN + YC + Se, LN diet + 10 g/kg YC + organic Se (1 mg/kg Se). Feeding trials of sows started from d 85 of pregnancy to d 35 of lactation. Compared with sows in the LN group, sows fed the LN + YC + Se diet had greater litter weaning weight, average litter gain, and milk fat content (14-d and 25-d milk) (P < 0.05). The content of malonaldehyde (MDA) (colostrum and 14-d milk) was lesser, and the activity of glutathione peroxidase (GSH-Px) (colostrum and 25-d milk) was greater when sows were fed the LN + YC + Se diet, compared with sows fed the LN diet (P < 0.05). Supplementation of YC and organic Se in the nutrient-restricted diet improved sows’ reproductive performance and pig weaning body weight by enhancing the antioxidant capacity and fat content in milk.     

Yield and composition of milk and weight gain of nursing pigs from sows fed diets containing fructose or dextrose

Yield and composition of milk and growth of nursing pigs in response to dietary treatment were estimated from 25 lactating sows during a 22-d period. Eight sows were fed 6 kg/d of a corn-soybean control diet (C sows). Nine were fed the control diet in which approximately 6.5 g X kg body weight (BW-1) X d-1 of carbohydrate was supplied by fructose corn syrup (F sows) and eight were fed the control diet containing equivalent carbohydrate supplied by powdered dextrose (D sows). Blood samples collected via jugular cannulae were analyzed for plasma concentrations of fructose, glucose and insulin. Concentrations of fructose and glucose from F sows were significantly higher throughout the study than that from D and C sows, while insulin concentration was approximately 2.5-fold lower. Milk yield from F sows on d 14 and 21 was significantly higher and pigs weaned on d 21 were heavier than those from D and C sows. Sows fed the diet containing fructose experienced significant BW loss during lactation. Coefficients of gross correlation across treatments showed milk yield and litter weight gain to be negatively associated with percentages of protein, lipids and total solids in milk, but positively associated with concentrations of lactose and gross energy. Nursing pig weight gain at weaning was more responsive to total yields of milk and milk nutrients than to composition. These data support the hypothesis that source of metabolizable energy (ME) affects milk yield, composition and efficiency at which the sow converts dietary nutrients into milk.     

Protein and fat utilization in lactating sows: I. Effects on milk production and body composition

In order to provide data with which to challenge a model of metabolism of lactating sows, we conducted a study to determine milk production and body and mammary composition in sows consuming a range of energy and amino acid intakes and nursing 11 to 12 pigs. Sows (2nd through 4th parity) consumed the same ration during gestation and consumed 6.1 kg/d (as-fed) for a 20 d lactation. Litter size was standardized at 12 pigs within 3 d of farrowing. Diets were formulated to provide three different amounts of protein intake and two different amounts of fat intake. Protein intakes of sows in high (HP), medium (MP), and low protein (LP) treatment groups were 863, 767, and 678 g/d with 59, 53, and 47 g/d lysine at two levels of fat intake, 117 (LF) and 410 g/d (HF). Number of pigs weaned per litter was 11.4 +/- 0.5 and milk production and litter weight gain was less (P < 0.01) in the last week of lactation for sows consuming the least protein. Medium and low protein intakes increased (P < 0.05) loss of body lean and protein. Change in carcass protein during lactation was -1.4, -3.0, -2.2, -1.2, -1.9 and -2.1 kg (SD 2.6) for sows fed HPLF, MPLF, LPLF, HPHF, MPHF, and LPHF. Body fat (carcass and visceral) change was 0.4, -3.7, -4.1, -0.3, 3.4, and -1.3 kg (SD 6.6) in HPLF, MPLF, LPLF, HPHF, MPHF, and LPHF groups. Total amount of mammary parenchyma increased more (P < 0.05) in sows fed a higher fat diet. These data are consistent with general knowledge of changes in body composition in lactation of sows. However, changes in body protein and fat were correlated across treatments and different from that reported for sows nursing smaller litters. These data help our quantitative understanding of nutrient flux in sows nursing large litters and allow a severe challenge of existing models of metabolism in sows.     

Influence of Carnichrome on the energy balance of gestating sows

Twelve multiparous sows with an average initial weight of 182 kg were used in a randomized complete block design to determine the effects of feeding Carnichrome (50 mg of carnitine and 200 microg of chromium picolinate per kilogram of feed, as fed) on energy and nitrogen utilization in early, mid-, and late gestation. All sows were fed a diet with or without Carnichrome for the preceding 28-d lactation, the weaning-to-estrus period, and for the duration of gestation. Daily feeding allowances over pregnancy were based on calculated energy and nutrient requirements to achieve a target sow maternal weight gain of 20 kg and remained constant throughout gestation. Heat production (HP) and its partitioning (activity, thermic effect of feeding short term [TEFst], basal) were determined in early (wk 5 or 6), mid- (wk 9 or 10), and late (wk 14 or 15) pregnancy using indirect calorimetry. Net maternal weight gain and total number of fetuses averaged 21.6 kg and 16.4, respectively. Organic matter and energy digestibility for the Carnichrome diet was greater (P < 0.05), which resulted in greater DE and ME contents (0.6%, P < 0.05) compared with the control diet. The digestibility coefficient of energy in the current experiment for a typical corn and soybean meal diet (92%) was greater than that predicted from DE values of corn and soybean meal in feeding tables (88%). Carnichrome had no effect on total HP, energy retained as protein or lipid, and maternal energy retention in early, mid-, or late gestation. Heat production in late gestation increased linearly (4.0 kJ/[kg BW0.75 x d]) for each additional day from d 90 to 110, despite the reduction of ME intake per unit of BW0.75. Metabolizable energy requirement for maintenance was 405 kJ/(kg BW0.75 x d). On average, activity HP was 116 kJ/(kg BW0.75 x d), which was equivalent to 20% of ME intake; however, this value ranged from 11 to 37% between sows, which corresponds to duration of standing ranging from 210 to 490 min/d. Energy cost of standing activity averaged 0.30 kJ/(kg BW0.75 x min). In conclusion, Carnichrome had no effect on the components of heat production and maternal weight gain during gestation, although it improved energy and organic matter digestibility of the diet.     

Effect of postweaning feeding on the performance and energy balance of female rabbits at different physiological states

The feeding of a high-fiber and low-energy diet to young rabbit does from weaning to the first kindling was used to modify their body reserves, stimulate their energy intake, and reduce the energy deficit during the first lactation. Rabbits (53 per group) were given ad libitum access to either a control or high-fiber diet (CP, 17.6 vs 15.8% of DM; crude fiber, 15.5 vs 19.9% of DM; digestible energy, 2,565 vs 2,261 kcal/kg of DM, respectively) from weaning to their first kindling. During lactation, both groups received the same diet, which contained 19.3% CP, 16.5% crude fiber, and 2,634 kcal/kg digestible energy (dry matter basis). Four comparative slaughters were performed to estimate the chemical and energy balance of rabbit does at different physiological states: at the beginning of the trial (12 rabbits, 45 d of age), at mating (10 rabbits per group, 136 d), at kindling (10 rabbits per group, 167 d), and at the end of lactation (12 and 11 rabbits for the control and the high-fiber group, 197 d). Large changes in body weight and composition were observed between slaughters. From 45 d to mating, doe body fat and energy increased 7.93 and 4.64 times the initial content, respectively. During pregnancy, body protein concentration decreased from 203 to 186 g/kg. At the end of lactation, body fat and energy concentration were reduced to values close to those measured at 45 d of age. Dietary treatment affected body chemical and energy balance during pregnancy and lactation but not reproductive and lactational performance. The high-fiber diet stimulated feed intake from weaning to the first kindling but not dietary energy intake. During lactation, the rabbits fed the high-fiber diet ate 10 kcal x d(-1) x kg live weight(-.75) more and lost less body fat (-405 vs -504 g) and body energy (-3,628 vs -4,294 kcal) than the does fed the control diet (P < .001). In the same period, all does showed water and protein retention (185 and 45 g, on average) regardless of dietary treatment. In conclusion, feeding young does a high-fiber diet until their first kindling reduced the chemical and energy body deficit at the end of the first lactation.     

Dietary energy source at two feeding levels during lactation of primiparous sows: I. Effects on glucose, insulin, and luteinizing hormone and on follicle development, weaning-to-estrus interval, and ovulation rate

Our objective was to study the effects of dietary-induced insulin enhancement during and after lactation on the reproductive performance of primiparous sows. During a 21-d lactation period, 48 sows were allotted to a 2x2 factorial experiment. Treatments were feeding level (high or low; 44 MJ or 33 MJ NE/d) and dietary energy source (fat or starch). After weaning, all sows received the same amount of feed (31 MJ NE/d from weaning to estrus and 17.5 MJ NE/d from breeding until slaughter) of the same energy source as fed during lactation. On d 7, 14, and 21 of lactation and d 22 (weaning), blood samples were taken every 12 min for 12 h and analyzed for plasma glucose, insulin, and LH. Sows were slaughtered on d 35 of the subsequent pregnancy, and ovulation rate was assessed. During lactation, postprandial plasma glucose and insulin concentrations were higher for sows fed the starch diet than for those fed the fat diet (P<.001), whereas feeding level had no effect. Basal and mean LH concentrations were not affected by treatments. The LH pulse frequency on d 7 of lactation was greater for sows fed the starch diet than for those fed the fat diet (.52 vs .17 pulses/12 h; P = .03). The high compared with the low feeding level resulted in a greater LH pulse frequency on d 21 of lactation (.89 vs .47 pulses/12 h; P = .05) and on d 22 (8.63 vs 5.77 pulses/12 h; P = .02), in a higher percentage of sows that exhibited estrus within 10 d after weaning (96 vs. 63%; P = .01), and a tendency for a higher ovulation rate (18.0 vs. 16.2; P = .09). Plasma glucose and insulin concentrations were not related to any of the LH traits. The LH pulse frequency after weaning was related to the weaning-to-estrus interval (WEI) and was best explained by a linear-plateau model. In sows fed the low feeding level, follicle size after weaning was correlated with LH pulse frequency after weaning and with the WEI, whereas in sows fed the high feeding level these correlations were not significant. Our results indicate that an improved dietary-induced insulin status during and after lactation does not overcome the inhibitory effects of lactation on subsequent reproduction at any of the feeding levels.     

The effect of late pregnancy feed allowance on the milk composition of the sow's colostrum and milk

The composition of colostrum and milk and of sows fed either 3.4 kg or 1.0 kg daily of a conventional sow diet during the last 14 days of gestation was investigated. The fat content of colostrum of the very restrictedly fed sows was higher compared with the standard fed sows. There was a significantly decrease in the crude protein and immunoglobulin contents of colostrum during the first 4 h post farrowing. The milk composition 14 days after farrowing was not affected by the late pregnancy feeding level. The composition of milk was significantly correlated with the 3 week litter weight. The colostrum IgG content was not correlated to the mortality of piglets during the first week post favouring. The content of crude protein and immunoglobulins in the milk was not correlated with the frequency of post weaning diarrhoea.     

High-fiber diets in pregnant sows: digestive utilization and effects on the behavior of the animals

Twelve pregnant, multiparous sows were assigned during gestation to three dietary treatments in a 3 x 3 Latin square design to evaluate the effect of increasing levels of crude fiber (CF): a conventional diet low in CF (L, 15.8 MJ DE/kg of DM, 3.3% CF), a diet with a medium level of CF (M, 14.4 MJ DE/kg of DM, 10.6% CF), and a high-fiber diet (H, 12.9 MJ DE/kg of DM, 18.1% CF). The daily feed supply was adjusted to provide the same 33.4 MJ of daily digestible energy (2.4, 2.7, and 3.0 kg/d for diets L, M, and H, respectively). Over the day, a shorter time standing was spent when sows received the H diet (291 min/d) compared with the L (363 min/d) and M diets (324 min/d). Duration of feeding was longer with the high-fiber diet. Mastication represented the main part of the feeding activity in sows fed the H diet (56%) and was reduced with the M and L diets (40% and 25%, respectively). Feeding rate increased when fiber level decreased (67, 120, and 152 g/min for the H, M, and L diets, respectively). Feeding the fibrous diet reduced the incidence of nonfeeding oral behaviors. These results show that high-fiber diets can reduce apparent feeding motivation of pregnant sows and, thus, improve the welfare of sows subjected to feed restriction.     

Survival and postweaning performance of pigs from sows fed fat during late gestation and lactation

Sows were fed a control corn-soybean meal gestation diet to d 80 of gestation. One group of sows (n = 25) continued receiving the control diet until the end of lactation, whereas two groups were placed on other treatments. One group (n = 27) was fed a diet containing 5% added solid fat pellets from gestation d 80 through lactation, whereas another group (n = 25) was fed a diet with 10% added solid fat pellet from gestation d 100 through d 14 of lactation. Feed supply was 2.27 kg/d during gestation and to appetite during lactation. Pigs from sows fed the control diet or 5% solid fat pellet diet were weaned with an age range of 22 to 28 d and immediately allotted in a 2 x 3 factorially designed 4-wk feeding trial. Pigs from these two sow groups were fed diets 1) without fat, 2) with 4.5% choice white grease or 3) with 5% solid fat pellet. Sow weight loss, backfat change and pig weights were not different at weaning among treatments. Survival rates of all pigs to 21 d averaged 90% with no significant differences between treatments. Pigs from fat-fed sows had more (P less than .05) glycogen per gram of liver, 41% more total liver glycogen and 16% more serum glucose at birth. Weanling pigs from fat-fed sows grew slower (P less than .05) than pigs from control sows. Supplemental fat during gestation increased liver glycogen of pigs, which should help survival, but the feeding of fat throughout lactation had a negative effect on ADG during a 4-wk postweaning period.     

Effects of dietary electrolyte balance on the chemistry of blood and urine in lactating sows and sow litter performance

One hundred fifty-three sows (average parity of 2.2) were used to determine the effects of dietary electrolyte balance (calculated as mEq/kg of diet for Na + K - Cl) on sows and their litters during lactation. The sows were fed corn-soybean meal-based diets (1.0% lysine, 1.0% valine, 0.95% Ca, and 0.80% P; as-fed basis) starting on d 109 of gestation and throughout the 21-d lactation experiment. Dietary electrolyte balance (dEB) was 0, 100, 200, 350, and 500 mEq/kg (as-fed basis), well above and below the dEB of 185 mEq/kg found in a simple corn-soybean meal-based lactation diet. To achieve the desired dEB, diets had the following: 1) 1.8% HCl (6 N) and 1.06% CaCl2, 2) 1.0% CaCl2, 3) 0.04% NaHCO3, 4) 1.29% NaHCO3, and 5) 2.54% NaHCO3 (as-fed basis). Increasing dEB increased blood pH (linear and quadratic effects, P < 0.001), partial pressure of carbon dioxide (linear effect, P < 0.001), HCO3- concentration (linear and quadratic effects, P < 0.001), and blood base excess (linear and quadratic effects, P < 0.001). However, increased dEB resulted in lower blood concentrations of K (linear and quadratic effects, P < 0.04), Cl (linear and quadratic effects, P < 0.001), and ionized Ca (linear and quadratic effects, P < 0.001). Changing dEB did not affect ADFI; water usage, litter weight gain; sow weight change; sow backfat change; percentages of CP, lactose, and fat in the milk; percentage of sows returning to estrus; days to estrus; and number of pigs born alive in the subsequent litter (P = 0.06). However, piglet survivability to d 10 and overall was greatest with the lower dEB treatments (linear effect, P < 0.05). The pH (linear and quadratic effects, P < 0.001) and colony forming units of total bacteria (linear effect, P < 0.03) in the urine increased as dEB of the diet was increased. In conclusion, dEB had pronounced effects on the physiological status of sows and decreasing dEB below that in a simple corn-soybean meal-based diet decreased bacterial counts in the urine and increased piglet survivability. However, milk composition, sow and litter weights at weaning, and subsequent rebreeding performance of the sows were not affected by dEB.