Effect of different feeding strategies and dietary fiber levels on energy and protein retention in gestating sows.

The aim of the study was to investigate whether increased inclusion of sugar beet pulp (SBP) alters retention of fat, protein, and energy when backfat (BF) is restored in early- and mid-gestation. In total, 46 sows were fed one of four dietary treatments with increasing inclusion of SBP providing dietary fiber (DF) levels of 119, 152, 185, and 217 g/kg; sows were assigned to one of three feeding strategies (FS; high, medium, and low) depending on BF thickness at mating and again at day 30 for the following month. On days 0, 30, 60, and 108, body weight (BW) and BF thickness were measured and body pools of protein and fat were estimated using the deuterium oxide technique. On days 30 and 60, urine, feces, and blood samples were collected to quantify metabolites, energy, and nitrogen (N) balances. On days 15 and 45, heart rate was recorded to estimate heat energy. At farrowing, total born and weight of the litter were recorded. In early gestation, BW gain (P < 0.01) and body protein retention increased (P < 0.05) with increasing fiber inclusion, while body fat retention increased numerically by 59%. The increase in BF was greatest for sows fed the high FS, intermediate when fed the medium strategy, and negligible for sows fed the lowest FS (P < 0.001). Nitrogen intake, N loss in feces, and N balance increased linearly, whereas N loss in urine tended to decrease with increasing inclusion of fibers in early gestation. Concomitantly, fecal energy output and energy lost as methane increased linearly (P < 0.001), while energy output in urine declined linearly. Total metabolizable energy (ME) intake therefore increased from 36.5 MJ ME/d in the low fiber group to 38.5 MJ ME/d in the high fiber group (P < 0.01). Changing the ME towards more ketogenic energy was expected to favor fat retention rather than protein retention. However, due to increased intake of ME and increased N efficiency with increasing fiber inclusion, the sows gained more weight and protein with increasing fiber inclusion. In conclusion, increased feed intake improved both fat and protein retention, whereas increased DF intake increased protein retention.

Feeding sows sugar beet pulp (SBP) has many known benefits, for example, increased satiety and high fermentability. This study investigates the ability of the sow to utilize energy for fat retention when replacing part of starch with dietary fiber. After a demanding lactation, sows need to restore body fat, and concomitantly avoid excessive protein retention, which will increase energy demand for maintenance and risk of locomotory problems. The hypothesis in this study is that energy from fermented fibers is more efficient for fat retention than dietary starch. In the study, sows had numerically greater fat retention when fed high concentrations of fiber from SBP, but concomitantly sows unintendedly also increased their protein retention, which in turn substantially increased their body weight. Sows were allocated to one of three feeding strategies depending on their body condition score (lean, medium, or fat) in early gestation, and backfat was efficiently restored in most sows within a month. In conclusion, although gestating sows have a high capability to utilize energy from fermentable fiber, they are disposed to protein over fat retention. These aspects need to be addressed in the nutrition of modern genotype sows.

Optimal protein concentration in diets for sows during the transition period.

The aim of the present study was to determine the optimal concentration of dietary protein required in transition diets for multiparous sows that enhance the farrowing process, colostrum production, and subsequent lactation performance. Forty-eight multiparous sows were allotted to one of six dietary treatments according to body weight (290 ±â€…3 kg) and parity (3.8 ±â€…0.2) from day 108 of gestation until 24 h after the onset of farrowing. The diets were isoenergetic and contained increasing concentrations of dietary protein (expressed as standardized ileal digestible [SID] Lys) and were supplied at a daily feed supply of 3.8 kg. On day 108 of gestation and days 2, 7, 14, 21, and 28 of lactation, body weight, and back fat thickness were recorded, and blood was sampled on day 108 of gestation, at the onset of farrowing, and days 3, 10, 17, and 24 of lactation from the sows for analysis of plasma metabolites. On day 115 of gestation, urine, and feces were collected for nitrogen (N) balance. The number of liveborn and stillborn piglets and time of birth were recorded and blood from every fourth piglet was sampled at birth for blood gas analysis. Piglets were weighed individually from birth until weaning, to estimate the colostrum and milk yield of the sows. Colostrum and milk samples were collected, and their compositions were determined. On days 3 and 28 of lactation, sows were injected with deuterium oxide to estimate body composition. The N utilization was maximized when the concentration of SID Lys in the transition diet was 6.06 g/kg (P < 0.01). When urinary concentrations of urea were expressed relative to creatinine, the relative concentration of urea remained low until a dietary concentration of 6.08 g SID Lys/kg, above which the relative concentration of urea increased (P < 0.01). Stillbirth rate increased linearly with increasing SID Lys concentration in the transition diet (P < 0.001), thus the concentration of SID Lys should be kept as low as possible without impairing sow performance excessively. A carry-over effect on milk yield was observed, showing that a dietary SID Lys concentration of 5.79 g/kg during transition optimized milk production at an average yield of 13.5 kg/d (P = 0.04). Increasing loss of body fat in lactation was observed with increasing SID Lys concentration in the transition diet (P = 0.03). In conclusion, the transition diet of multiparous sows should contain 5.79 g SID Lys/kg when fed 3.8 kg/d (13.0 MJ ME/kg), for a total SID Lys intake of 22 g/d.

In late gestation, the protein requirement of sows increases rapidly due to growth of the fetuses and mammary glands, whereas their energy requirement only is slightly increasing. Recent studies show that a feed supply of 4.1 kg/d in the last week of gestation is beneficial for the farrowing process and subsequent lactation performance. However, studies on feed supply cannot separate the effects of dietary fractions, so the sows' requirement for protein in the transition period remain unclear. The aim of the present study was to determine the dietary protein requirement of multiparous sows using a dose­response design with six diets containing increasing dietary protein (expressed as standardized ileal digestible [SID] Lys) from 3.99 to 8.57 g SID Lys/kg at a feeding level of 3.8 kg/d. Results indicate that the utilization of nitrogen (protein) during the transition period was maximized when the diet contained 6.06 g SID Lys/kg. Colostrum yield was unaffected by dietary treatment while dietary SID Lys in transition diet was found to have a carry-over effect on milk yield in the subsequent lactation period that was optimized at 5.79 g SID Lys/kg. As the concentration of SID Lys in the transition diet increased, stillbirth rate also increased, therefore, the concentration of SID Lys should be kept as low as possible without impairing sow performance excessively. In conclusion, the transition diet of multiparous sows should contain 5.79 g SID Lys/kg when fed 3.8 kg/d (13.0 MJ ME/kg), for a total SID Lys intake of 22 g/d.

The effect of dietary omega-3 fatty acid supplementation on fetal growth, piglet birth weight and plasma fatty acid concentrations, using docosahexaenoic acid in early gestation in sows.

The objective of the study was to test the effect of the omega-3 fatty acid docosahexaenoic acid (DHA) on fetal and placental development as well as the birth weight of piglets. A total of 238 multiparous sows were allocated to either a control diet group or a DHA diet group with an omega-6 to omega-3 ratio of 9.8 and 2.4, respectively, from mating to day 43 of gestation. A blood sample was collected and back fat thickness was measured prior to mating, on days 14, 42 and 112 of gestation. On day 43 of gestation, 14 sows were slaughtered and measurements of fetuses and placentas were taken. Piglets in some litters were weighed individually at farrowing. Dietary treatment did not affect fetal characteristics and back fat thickness (P > 0.05). Dietary treatment increased the plasma concentrations of total omega-3 fatty acids in sows (P < 0.05). Sows fed the DHA diet had a shorter gestation length compared to the control sows (P < 0.05), but the number of born piglets was not affected (P > 0.05). The average piglet birth weight and the within-litter variation in birthweight were unaffected by dietary DHA (P > 0.05), however, sows fed DHA diet had fewer piglets under 800 g at birth compared to control sows (P < 0.05). In conclusion, addition of DHA decreased the dietary ratio of omega-6 to omega-3 fatty acids, increased plasma n-3 fatty acid concentrations in sows and decreased the number of piglets weighing under 800 g at birth.

Feeding level during the last week of gestation can influence performance of sows and their litters in the subsequent lactation.

This study investigated the impact of feeding level during the last week of gestation on performance of sows and their litters in the subsequent lactation. A total of 48 sows were assigned to one of six feeding levels (1.8, 2.4, 3.1, 3.7, 4.3, or 5.0 kg/d) from day 108 of gestation until farrowing. Post-farrowing, all sows were fed similarly during lactation with a gradual increase in feed allowance in accordance with Danish recommendation until it reached the maximum allowance of 9 kg/d on day 17 of lactation. Plasma samples were collected from the sows during farrowing and lactation, and sow's body weight and backfat thickness, and milk samples were taken during lactation. Litters were standardized to have 13 to 15 piglets each and weighed once weekly during lactation. Plasma concentrations of urea, acetate, and butyrate in sows linearly increased (P < 0.001), while non-esterified fatty acids linearly decreased (P < 0.001) during farrowing with increasing feeding level. Moreover, concentrations of triglycerides (P < 0.001), acetate (P = 0.007), and succinate (P < 0.001) were greater in plasma collected at the onset of farrowing compared to the end of farrowing. Conversely, concentrations of glucose, urea, and butyrate (P < 0.001) were lower in plasma collected at the onset of farrowing than at the end. Sows fed 2.4 and 3.1 kg/d exhibited greater triglyceride concentrations than those fed 3.7 (P = 0.03) and 5.0 (P = 0.02) kg/d. Sows fed 1.8 kg/d during the last week of gestation had lower milk yield in wk 1 (P < 0.001) and wk 2 (P = 0.001) of lactation compared to the other groups. Additionally, litter weight gain (P = 0.04) and litter weaning weight (P = 0.007) were lower in sows fed 1.8 kg/d compared to the other groups. The greatest milk yield, litter growth, and litter size were observed in sows fed 3.7 kg/d during the last week of gestation, whereas the estimate generated by the regression model revealed that sows should have been provided with 4.0 to 4.1 kg/d as an adequate feeding level to maximize these performances in the subsequent lactation. Interestingly, feeding level during the last week of gestation did not influence feed intake during lactation. In conclusion, this study highlights the significance of adequate feed supply (4.0 to 4.1 kg/d) during the last week of gestation in order to maximize performance of sows in the subsequent lactation.

Feeding sows at high or ad libitum level during an extended gestation period has been found to have a negative impact on the subsequent lactation performance. Conversely, in some European countries, it has been a common practice to reduce the feed allowance during the last 2 to 3 d before expected farrowing to mitigate issues like constipation and postpartum health problems such as mastitis, metritis, and agalactia. However, recent studies suggest that sows should be fed approximately 4 kg/d during transition period to improve farrowing performance. In the present study, we investigated the carry-over effects of feeding level (dose­response design) during the last week of gestation on lactation performance of sows and their litters in the subsequent lactation. The findings revealed that a lower feeding level during the last week of gestation reduced milk yield and litter size at weaning. Milk yield, litter growth, and litter size at weaning were greater in sows supplied with 3.7 kg/d during the last week of gestation. However, the estimate generated by the regression model indicates that sows should be provided with 4.0 to 4.1 kg/d during the final week of gestation to enhance their performance in the subsequent lactation. Therefore, the present results emphasize the benefits of maintaining an adequate feeding level during the last week of gestation to improve sows' lactation performance in the subsequent lactation.

Influence of four fiber-rich supplements on digestibility of energy and nutrients and utilization of energy and nitrogen in early and mid-gestating sows.

The digestibility of energy and nutrients in fiber-rich diets depends greatly on the fiber source but most data are from studies with growing pigs. The purpose of this study was to investigate the apparent total tract digestibility (ATTD) of nutrients in different fiber-rich diets and to quantify whole-body metabolism and utilization of energy and nitrogen (N) in gestating sows. Four fiber-rich diets based on sugar beet pulp (SBP), soy hulls (SH), palm kernel expellers (PKE), or a mixed fiber (MF) were formulated, with an average daily intake of total fiber (TF) of 471, 507, 651, and 437 g/d, respectively. A total of 48 multiparous sows were stratified by body weight at mating (day 0) and assigned to one of the four diets throughout gestation. Body weight and backfat were measured, and body pools of fat and protein were estimated using the deuterium oxide dilution technique at days 0, 30, and 60. On days 30 and 60, urine and fecal grab samples were obtained. On days 15 and 45, heart rate was measured to estimate total heat production. The ATTD of nutrients differed across treatments (P < 0.001), while in vivo organic matter digestibility deviated with up to ±3.3% units from in vitro enzyme digestibility of organic matter. The ATTD of energy was highly negatively correlated with intake of lignin (P < 0.001), while ATTD of N was highest (negatively) correlated (P < 0.001) with intake of insoluble non-starch polysaccharides (NSP). The ATTD of all nutrients except NSP was lowest in PKE-fed sows and highest, except for N, in sows fed the SBP diet. The ATTD of N was highest in the MF-fed sows and ATTD of NSP was lowest in the MF-fed sows. Sows lost most energy as heat (53% to 72% of gross energy intake), followed by energy in feces (15% to 17%), urine (3% to 4%), and methane (0.5% to 0.9%). Energy for maintenance accounted for the majority of the heat production and the total energy retention was lowest and highest in the SBP- and PKE-fed sows, with a retention of 3.3 and 13.3 MJ/d, respectively (P < 0.001). Sows lost most N through urine, the lowest and highest N loss (relative to intake) was observed in SH- and SBP-fed sows (50% to 63%, respectively), while 14% to 26% was retained as body protein. In conclusion, the fiber-rich diets were utilized efficiently by gestating sows with respect to energy with ATTD values above 82% in all four fiber-rich diets, whereas the high TF content in the diets compromised the N utilization in gestating sows.

How much energy and nutrients a pig can use from the feed depends greatly on the feed ingredients, feed level, and the physiological stage of the animal. Fibers are of great interest because they can improve health and welfare of pigs and co-products from the food and agriculture industries are among the most interesting. The ability to degrade different fiber sources and utilize energy and nutrients are poorly understood in gestating sows, but highly important when formulating the feed composition. The hypothesis was that sugar beet pulp was superior to the other three fiber-rich sources investigated: soy hulls, palm kernel expellers, or a mix of fibers, with respect to intake and utilization of energy and nutrients. We did not find sugar beet pulp to be particularly superior with respect to energy (fermentation or utilization), whereas utilization of nitrogen was highest for sugar beet pulp but compromised in the three other diets depending on fiber sources.

Feeding the modern sow to sustain high productivity.

Selection for hyper-prolific sows has increased the litter size by more than 50% during the last three decades, and proper nutrition of the female pigs has concomitantly changed due to improved prolificacy and productivity of gilts and sows. This review summarizes the physiological characteristics and nutritional challenges associated with feeding modern hyper-prolific sows during the gilt rearing period and during gestation, transition, and lactation periods. The review presents up-to-date knowledge of the energy and lysine requirements of female pigs and focuses on how nutrition may increase fat gain and limit protein and weight gain in the gilt rearing period and in early and mid-gestation. In late gestation, fetal and mammary growth should be considered and during the transition, colostrum yield and farrowing performance need to be optimized. Finally, milk production should be optimized and body mobilization should be minimized in the lactation period to achieve high feed efficiency in hyper-prolific sows.

Fetal and placental development in early gestation of hyper-prolific sows.

Modern hyper-prolific sows produce large litters with a high within-litter variation in birth weight and an increased number of low-birth-weight piglets per litter with higher mortality rates and lower growth rates compared to heavier littermates. This study aimed to describe fetal development in hyper-prolific sows, to characterize differences between large and small fetuses, and to determine when within-litter variation in fetal weight can be detected. Forty-seven multiparous sows were blood-sampled and slaughtered at day 28, 33, 45, 50, and 56 of gestation. Number of fetuses were counted, fetal body and organ weights were measured, and the intrauterine positioning was recorded. Length, width, and area of each placenta was measured and the fetus weight/placental weight ratio was calculated. The umbilical cords of the smallest, medium and the largest fetus of each litter were sampled for histological analysis. In total measurements were obtained for 1161 fetuses. The results revealed no difference in fetal survival between the gestational days (P > 0.05). Intrauterine positioning near the cervix significantly reduced fetal weight at day 56 (P < 0.05). Total litter weight and average fetal weight increased with gestational age and individual fetal weight was negatively affected by litter size from day 33 and onwards (P < 0.05). The coefficient of variation for within-litter variation in fetal weight was higher at day 28 compared to the other gestational days (P < 0.05). Relative brain- and heart weights decreased from day 28-56 (P < 0.001). Small fetuses had relatively heavier brains and hearts at day 45, 50 and 56 (P < 0.001). Size of placenta, fetus weight/placental weight ratio and length of umbilical cord increased with gestational age (P < 0.001). There was a positive correlation between size of placenta and weight of individual fetus (P < 0.001), the weight of the fetus was positively correlated with umbilical cord length (P < 0.001) and the umbilical cross-sectional area was correlated to fetal weight at day 56 (P < 0.01). Individual fetal weight was positively correlated to the fetus weight/placental weight ratio (P < 0.001). In conclusion, fetal growth was affected by litter size, placental weight, and -area, and umbilical cord length. Lightweight fetuses were characterized by having placentas with lower weight and area and shorter umbilical cords. Lastly, within-litter variation in fetal weight was detectable at day 28, and the coefficient of variance remained stable from day 33-56.

Increased feed supply and dietary fiber from sugar beet pulp improved energy retention in gestating sows.

The aim of the study was to investigate whether increased inclusion of sugar beet pulp (SBP) alters retention of fat, protein, and energy when backfat (BF) is restored in early- and mid-gestation. In total, 46 sows were fed one of four treatments with increasing inclusion of SBP with dietary fiber (DF) levels of 119, 152, 185, and 217 g/kg; sows were assigned to one of three feeding strategies (FS; high, medium, and low) depending on BF thickness at mating and again at day 30 for the following month. On days 0, 30, 60, and 108, body weight (BW) and BF thickness were measured, and body pools of protein and fat were estimated using the deuterium technique. On days 30 and 60, urine, feces, and blood samples were collected to quantify metabolites, energy, and N balances. On days 15 and 45, heart rates were recorded to estimate the heat production. At farrowing, total born and weight of the litter were recorded. In early gestation, BW gain (P < 0.01) and body protein retention increased (P < 0.05) with increasing fiber inclusion, while body fat retention increased numerically by 59%. Increase in BF was the greatest for sows fed the high FS, intermediate when fed the medium strategy, and negligible for sows fed the lowest FS. N intake, N loss in feces, and N balance increased linearly, whereas N loss in urine tended to decrease with increasing inclusion of fibers in early gestation. Concomitantly, fecal energy output and energy lost as methane increased linearly (P < 0.001), while energy output in urine declined linearly, and total metabolizable energy intake, therefore, increased from 40.5 MJ ME/d in the low-fiber group to 43.5 mega joule (MJ) metabolizable energy (ME)/d in the high-fiber group (P < 0.001). Changing the metabolizable energy toward more ketogenic energy was expected to favor fat retention rather than protein retention. However, due to increased intake of metabolizable energy and increased N efficiency with increasing fiber inclusion, the sows gained more weight and protein with increasing fiber inclusion. In conclusion, increased feed intake improved both fat and protein retention, whereas increased DF concentration increased protein retention.

Feeding sows sugar beet pulp (SBP) has many known benefits, for example, increased satiety, and it is a highly fermentable fiber source for sows. This study investigates how efficient sows utilize energy for fat and protein retention in response to increased SBP inclusion in the diet. After a demanding lactation, sows need to restore body fat and concomitantly avoid excessive protein retention, which increases energy demand for maintenance and risk of locomotory problems. The hypothesis in this study was that energy from fermented fibers is more efficient for fat retention than dietary starch. In the study, sows had numerically greater fat retention when fed high concentrations of fiber from SBP, but, concomitantly, sows unintendedly also increased their protein retention, which in turn increased substantially their live weight. Sows were fed one of three feeding strategies depending on the body condition score (lean, medium, or fat) in early gestation, and backfat was efficiently restored in most sows within a month. To conclude, gestating sows have a high capability to utilize energy from fermented fiber, but sows prefer to retain protein rather than fat, which needs to be addressed in the nutrition of modern genotype sows.

Identifying Risk Factors for Low Piglet Birth Weight, High Within-Litter Variation and Occurrence of Intrauterine Growth-Restricted Piglets in Hyperprolific Sows.

This study aimed to identify risk factors affecting PBW, high CVPBW and the occurrence of IUGR piglets in 12 commercial Danish herds with hyperprolific sows using free-access stalls, floor or electronic sow feeding systems in the gestation unit. The following factors were investigated: the duration of previous lactation, the length of the interval from weaning to insemination, the length of gestation, litter size, parity, sow backfat thickness in late gestation and the type of feeding system in the gestation unit. The study included newborn piglets from 452 litters with the following production indicator averages: 21.3 piglets/L, 1235 g PBW, 22.9% CVPBW and 10.9% and 11.8% within-litter occurrence of severe and mild IUGR piglets, respectively. Increasing length of weaning-to-insemination interval decreased PBW by 25.8 g/day. For 2nd to 9th parity sows, each additional piglet in the litter increased CVPBW by 0.38%, the occurrence of severe IUGR piglets by 0.68% and mild IUGR piglets by 0.50%. Sows of 5th parity and older had a 1.39% higher CVPBW and 49.1 g lighter piglets compared with sows of 2nd to 4th parity. PBW was lower in one ESF herd, suggesting complex interactions that need to be further elucidated. The main critical risk factor observed was litter size.

Impact of four fiber-rich supplements on nutrient digestibility, colostrum production, and farrowing performance in sows.

This study aimed to investigate the impact of dietary fiber (DF) sources on sow and litter performance, and apparent total tract digestibility (ATTD) of gross energy (GE) and nutrients. A total of 48 sows were stratified for body weight at mating and randomly assigned to one of four DF sources (mixed fiber [MF], palm kernel expellers [PKE], sugar beet pulp [SBP], or soy hulls [SH]) and fed the diet from mating until farrowing. Within DF treatments, sows were supplemented with one of two extra energy sources (glycerol or sugar dissolved in water), whereas a third group (control) received water from day 108 of gestation until farrowing. The number of total born, live-born, and stillborn pigs; birth time and birth weight of the pigs; farrowing duration; and farrowing assistance (FA) were recorded. Live-born pigs were weighed again at 12 and 24 h after birth to record weight gain, which was used to estimate intake and yield of colostrum. Blood samples were collected once daily from day -3 relative to farrowing until day 1 after farrowing in sows and once from selected pigs right after birth. Fecal samples were collected on day 114 of gestation and colostrum at 0, 12, 24, and 36 h after onset of farrowing. Intake of soluble and insoluble nonstarch polysaccharides (NSP) was greater for SBP (P < 0.001) and PKE (P < 0.001) supplemented sows, respectively, when compared with other groups. Farrowing duration and stillbirth rate were not affected by DF sources, but PKE and SH supplemented sows had greater FA than SBP and MF supplemented sows (P < 0.001). Extra energy supplement did not improve the farrowing performance. Concentration (P = 0.02) and output (P = 0.04) of dry matter in colostrum, and ATTD of GE (P < 0.001) and crude protein (CP; P < 0.001) were lower for PKE supplemented sows than in sows from the remaining groups. Intake of insoluble NSP correlated negatively with ATTD of GE (P < 0.001) and CP (P < 0.001). Concentrations of glucose (P < 0.001), lactate (P < 0.001), CO2 (P < 0.001), and HCO3 (P < 0.001) in sows blood were increased with time progress relative to farrowing. Newborn pigs from PKE supplemented sows had greater concentration of lactate (P = 0.02) and lower blood pH (P = 0.02) than the remaining treatments. In conclusion, PKE supplement reduced ATTD of GE and CP, and concentration and output of dry matter in colostrum but increased FA. Results of this experiment indicated that the use of PKE as a fiber source for late gestating sows should be avoided.

The Effect of Different Feeding Systems on Salivary Cortisol Levels during Gestation in Sows on Herd Level.

The aim of this study was to investigate herd cortisol levels as an indicator of stress during gestation in three different feeding systems. Twelve commercial Danish herds with 800 to 3050 sows were included, with either free-access feeding stall (Stall), floor feeding (Floor), or electronic sow feeding (ESF; n = 4 herds per system). Saliva samples were collected from 30 sows/herd in the gestation unit for cortisol analysis with an average of 67.2 gestation days for ESF, 72.4 days for Floor, and 68.6 days for Stall. Data on piglet birth weight (PBW) and the percentage of intrauterine growth restricted (IUGR) piglets from 452 litters (9652 piglets, 8677 liveborn) from all 12 herds were obtained on the saliva collection days. The cortisol levels in saliva increased throughout gestation (p < 0.01), and lower concentrations were observed among sows belonging to Stall (4.80 nmol/L), compared to Floor (7.03 nmol/L) and ESF (7.87 nmol/L), and that difference was significant as an independent effect in the case of ESF (p < 0.01). There was no difference between Floor and ESF or Stall and Floor (p > 0.05). An interaction was observed between parity and feeding system, with parities 4-5 in ESF herds having lower levels than other parities within the ESF system (p = 0.02).

The effects of long- or short-term increased feed allowance prior to first service on litter size in gilts.

Replacing stock is costly in any pig production. In addition, it takes time for young animals to reach the same level of productivity as more mature animals. Therefore, the aim of this study was to investigate the effects of long- or short-term increased feed allowance (covering the luteal and follicular phases) prior to service in the second estrus on first parity performance. In order to achieve this, altrenogest was used to synchronize the gilts cycle to allow a precise feeding strategy, and only gilts inseminated 0-10 d after altrenogest withdrawal were included in the study. Altrenogest was given at days 0-18 to control the luteal phase and, therefore, treatments covered different feeding strategies in either or both the luteal phase (days 0-18) and follicular phase (days 18-25). High feed allowance (H) was induced using 0.97 kg more feed per day compared to the low feed allowance (L) given 2.33 kg/d. Four feeding strategies, low-low (LL), high-high (HH), high-low (HL), and low-high (LH), were included. Once gilts had been inseminated, feed allowance was reduced to 2.23 kg/d to prevent the loss of embryos in early gestation. A tendency was observed between feeding strategy and backfat thickness before altrenogest treatment, showing that total born piglets were positively correlated to backfat in the LL and LH (no increased feed allowance or short-term increased feed allowance), treatments (P = 0.076), compared to when gilts had longer periods with high feed allowance (HH and HL). High feed allowance in the follicular phase (LH) tended to increase the number of total born piglets compared to the other groups (P = 0.069) when applied in the follicular phase of the second standing estrus after the gilts were given altrenogest. This would be equivalent to the last 5-7 d of a 21-d cycle in gilts. The three other feeding strategies, comprising either the luteal and follicular phases (HH) or the luteal phase (HL) or none (LL), did not increase litter size. The weight of the gilt when entering the insemination section also had an effect on total born piglets (P < 0.001) with an increase in litter size with increased weight of the sow, but no differences between treatments. In conclusion, the weight of the gilt had an influence on the total litter size and gilts with low backfat tended to respond more positively to a longer period with high feed allowance than fatter gilts.

Optimal feed level during the transition period to achieve faster farrowing and high colostrum yield in sows.

This study aimed to determine the optimal supply of lactation feed during the transition period to minimize farrowing duration (FD) and maximize colostrum yield (CY) and quality with the overall aim of reducing piglet mortality. A total of 48 sows were stratified for body weight and assigned to six levels of feed supply (1.8, 2.4, 3.1, 3.7, 4.3, and 5.0 kg/d) from day 108 of gestation until 24 h after the onset of farrowing. The number of total born, live-born, and stillborn piglets; birth time and birth weight of each piglet; and frequency of farrowing assistance (FA) was recorded, and blood samples were obtained from newborn piglets at birth. Live-born piglets were further weighed at 12 and 24 h after birth to record weight gain, which in turn was used to estimate intake and yield of colostrum. Colostrum samples were collected at 0, 12, 24, and 36 h after the onset of farrowing. FD was shortest (4.2 h) at intermediate (3.7 kg/d), longest (7.1 to 7.6 h) at low (1.8 and 2.4 kg/d), and intermediate (5.6 to 5.7 h) at high (4.3 and 5.0 kg/d) feed intake (P = 0.004; mean comparison). FA was lowest (0.7% to 0.8%) at intermediate feed intake (3.7 and 4.3 kg/d) and substantially elevated (4.3% to 4.7%) at both lower and higher feed intake (P = 0.01; mean comparison). The cubic contrast revealed 4.1 kg/d as the optimal feed intake to achieve the shortest FD and to minimize FA. Newborn piglets from second-parity sows were less vital than piglets from gilts as evaluated by blood biochemical variables immediately after birth. CY was greatest at 3.1 kg/d (P = 0.04), whereas the cubic contrast revealed 3.0 kg/d as the optimal feed intake to maximize CY. Concentrations of colostral components were affected by the diet, parity, and their interaction except for lactose concentrations. In conclusion, the study demonstrated the importance of proper feed level during the transition period on sow productivity. Moreover, this study estimated 4.1 and 3.0 kg/d as the optimal feed intake during the transition period to improve farrowing characteristic and CY, respectively, and these two feed intake levels supplied daily 38.8 MJ metabolizable energy (ME) and 23.9 g standardized ileal digestible (SID) lysine (3.0 kg/d) or 53.0 MJ ME and 32.7 g SID lysine (4.1 kg/d). The discrepancy of optimal feed intake for optimal farrowing and colostrum performance suggests that it may be advantageous to lower dietary lysine concentration in the diet fed prepartum.

Optimal lysine in diets for high-yielding lactating sows1.

The objective of the current study was to determine the optimal concentration of dietary standardized ileal digestible (SID) Lys required to maximize litter gain and minimize sow BW loss in modern high-yielding lactating sows when SID CP was kept constant across dietary treatments. A total of 396 parity 1 to 5 sows (L × Y, DanBred, Herlev, Denmark) were included in the study from day 3 after farrowing until weaning at day 26. Sows were allocated to 6 dietary treatments increasing in SID Lys concentration (6.19, 6.90, 7.63, 8.33, 9.04, and 9.76 g/kg). Diets were isoenergetic (14.04 MJ ME/kg as-fed). Litters were standardized to 14 piglets at day 3 ± 2 d postpartum. At day 3 ± 2 d and at day 26 ± 3 d in lactation, litter weight, and sow BW and back fat were registered. On a subsample of 72 parity 2 to 4 sows, litters were additionally weighed at days 10 and 17 ± 3 d, and milk and blood were sampled at day 3 ± 2 d, and 10, 17 and at 24 ± 3 d in lactation. For the 72 sows, body pools of fat and protein were also determined at days 3 ± 2 and 26 ± 3 d using the D2O dilution technique. All data were analyzed as a randomized complete block design using PROC MIXED in SAS. Furthermore, data were subjected to linear and quadratic polynomial contrasts. Variables with quadratic or linear effects or days in milk × treatment interactions were selected for analysis in PROC NLMIXED using linear broken-line models to evaluate optimal SID Lys concentrations. Only models that converged and the best fitting models were included. Average daily litter gain increased until a breakpoint at 8.11 g/kg of SID Lys (as-fed). At and above the breakpoint, multiparous and primiparous sows had litter gains of 3.36 and 2.93 kg/d, respectively. Weaning litter size (13.0 ± 0.1) was similar between the 6 dietary treatments (P = 0.28). Lactation sow BW loss was minimized to 0.17 kg/d at 9.05 g/kg of SID Lys and sow body protein loss was minimized to 0.23 kg at 9.22 g/kg of SID Lys. Linear broken-line analyses showed that for 3, 10, 17, and 24 DIM, plasma urea was minimized at 7.02, 8.10, 8.73, and 8.32 g/kg of SID Lys, respectively, and milk fat was maximized at 7.80 g/kg of SID Lys. In conclusion, in our conditions, high-yielding lactating sows required 8.11 g/kg of SID Lys to maximize litter gain and 9.05 g/kg of SID Lys to minimize sow BW loss. Based on plasma urea, the optimal dietary concentration of SID Lys was lowest in week 1, intermediate in week 2 and 4, and greatest in week 3 of lactation.

Optimal crude protein in diets supplemented with crystalline amino acids fed to high-yielding lactating sows1.

The objective of the current study was to determine the requirement of standardized ileal digestible (SID) CP for maximal litter gain in high-yielding lactating sows due to insufficient supply of either His, Leu, Val, Ile, or Phe. The content of SID Lys was formulated at 95% of the recommended level, while that of Met, Met+Cys, Thr, and Trp was formulated at 100% of the recommended level or slightly greater using crystalline AA. A total of 540 parity 1 to 5 sows (L×Y, DanBred, Herlev, Denmark) were included in the study from day 3 after farrowing until weaning at day 26. Sows were allocated to six dietary treatments increasing in SID CP content (96, 110, 119, 128, 137, and 152 g/kg). Litters were standardized to 14 piglets at day 3 ± 2 after farrowing. At day 3 ± 2 after farrowing and at day 26 ± 3, sow BW and back fat, and litter weight were recorded. On a subsample of 72 sows (parity 2 to 4), litters were also weighed at days 10 and 17 ± 3, and milk and blood were sampled at day 3 ± 2 d, and 10, 17 and at 24 ± 3 d in lactation. Sow body pools of protein and fat were determined on the 72 sows at days 3 ± 2 and 26 ± 3 d using the D2O dilution technique. All data were subjected to ANOVA, and to linear and quadratic polynomial contrasts. Variables with quadratic effects or days in milk × treatment interactions were analyzed using linear regression or one-slope linear broken line using the NLMIXED procedure of SAS. Average daily litter gain reached a breakpoint at 125 g SID CP/kg (as-fed). Multiparous sows had a greater litter gain than primiparous sows (3.33 vs. 3.02 kg/d above the breakpoint; P < 0.001) but litter size (13.1 ± 0.1) at weaning were unaffected by dietary treatment (P = 0.62). Sow BW loss was minimized at 102 g SID CP/kg. Concentrations of protein and casein in milk increased linearly with increasing SID CP (P < 0.001). Milk urea reached a minimum at 111-118 g SID CP/kg (P < 0.05) and milk fat a maximum at 116 g SID CP/kg (P < 0.05). In conclusion, 125 g SID CP/kg feed was required to maximize litter gain.

Nitrogen utilization of lactating sows fed increasing dietary protein1.

The objectives of the study were 1) to quantify dietary N utilized for milk N and N loss in urine and feces, in sows fed increasing dietary CP with a constant amount of Lys, Met, Thr, and Trp to meet their standardized ileal digestible (SID) requirement and 2) to determine the optimal dietary CP concentration based on dietary N utilization for milk production. Seventy-two sows were fed 1 of 6 dietary treatments, formulated to increase the SID CP as followed: 11.8, 12.8, 13.4, 14.0, 14.7, and 15.6% and formulated to be isocaloric (9.8 MJ NE/kg). Diets were fed from day 2 after parturition until weaning at day 28 (± 3 d). Litters were equalized to 14 piglets and weighed within 48 h following parturition. Sows were weighed and back fat scanned, at day 18 (± 3 d) and day 28 (weaning; ± 3 d). Litter weight was recorded at day 11, 18 (± 3 d), and 28 (± 3 d). Nitrogen balances were conducted on approximately day 4, 11, and 18 (± 3 d). Daily milk yield was estimated from recorded litter gain and litter size. To calculate sows mobilization of fat and protein, body pools of fat and protein were estimated by D2O (deuterated water) enrichment on day 4 and 18 (± 3 d). No linear, quadratic, or cubic effects of increasing dietary CP was observed for sows total feed intake, sow BW, body pools of protein and fat, protein and fat mobilization, total milk yield, and piglet performance. The protein content in milk increased linearly with increasing dietary CP in week 1 (P < 0.05), week 2 (P < 0.05), and week 3 (P < 0.001). Urine production did not differ among treatments and N output in urine increased linearly with increasing dietary CP concentration in week 1 (P = 0.05), week 2 (P < 0.001), and week 3 (P < 0.001). Urine N excretion relative to N intake increased linearly with increasing dietary CP (P < 0.001). Milk N utilization relative to N intake decreased linearly from 77.8% to 63.1% from treatment 1 through 6 (P < 0.001). Corrected milk N utilization decreased from 68.6% to 64.2% from treatment 1 through 6 (P < 0.05). In conclusion, a low dietary CP concentration for lactating sows with supplemented crystalline AA improved the efficiency of dietary N utilization and reduced the N output in urine without affecting lactation performance.