Impact of litter size, supplementary milk replacer and housing on the body composition of piglets from hyper-prolific sows at weaning.

The modern hyper-prolific sow gives birth to 17 live-born piglets on average. An alternative strategy to nurse sows and artificial rearing may be providing milk replacer while letting all the piglets stay with their dam. However, milk replacer is of lower nutritional quality than sow milk and may reduce the body fat content of piglets who use milk replacer to compensate for low suckling success due to competition at the udder. Therefore, the aim of this study was to investigate the body composition at weaning of two random sow-reared piglets per litter from 93 litters by using the deuterium oxide dilution technique. The piglets were part of large study with a 2×2×2 factorial design of either 14 or 17 piglets from day 1 (LS: LS14/LS17) with or without access to milk replacer (MILK: -MILK/+MILK) and reared by crated or loose-housed sows (HOUSING: CRATE/ LOOSE). From behavioral observations day 21 in +MILK, piglets were divided according to their frequency of drinking milk replacer and suckling (Nutrition Source). Increasing LS from 14 to 17 reduced the average daily gain from 258 to 228 g/d and body fat % from 14.4 to 12.7% (P<0.01). In a two-way interaction between LS and HOUSNG, the body fat percentage was lower (P=0.04) and the water percentage tended to be higher (P=0.07) in LS17 CRATE compared to the other treatments (i.e. LS17 LOOSE, LS14 CRATE and LOOSE). There was no effect of MILK on piglet composition day 28 (P>0.1). In +MILK, the Nutrition Source affected piglet body composition (P<0.05) as piglets with low suckling frequency (LOW) had lower body fat and higher water content compared to piglets who had high suckling frequency (SUCKLE). Unexpectedly, drinking milk replacer in addition to suckling (MIXED) did not increase piglet body fat content. Relying mainly on milk replacer (CUP) caused body fat and water contents to be intermediate to piglets with high (SUCKLE and MIXED) and low suckling frequency (LOW). In conclusion, LS had a clear impact on piglet growth and body composition at weaning. In contrast, supplementation of milk and housing had only negligible impact on litter performance. Some individual piglets that had low frequency of sow milk intake benefitted from milk supplementation. Loose housing appeared to benefit piglet body fat at weaning but this was due to a greater piglet mortality.

Impact of sow parity on yield and composition of colostrum and milk in Danish Landrace × Yorkshire crossbred sows.

The present study aims to characterize the colostrum, milk yield and composition and to determine whether sow parity would influence yield and composition of colostrum and milk in Danish Landrace × Yorkshire crossbred sows. The data were collected from sow parity numbers 1 (n = 27), 2-4 (n = 48) and 5-6 (n = 30) from Danish Landrace × Yorkshire crossbred sows reared in a commercial swine herd in Thailand. The piglets were weighed on day 0 (<1 h), 1 (24 h), 3, 10 and 17 after birth to determine the colostrum and milk yields of the sows using a prediction equation. Milk samples were collected manually within 1 h of the onset of parturition and on days 3, 10 and 17 after farrowing to evaluate milk composition. A general linear model procedure was used to analyze the effects of sow parity numbers on colostrum yield and composition and a general linear mixed model procedure was used to analyze the effects of sow parity numbers on yield and composition of milk. The model included the fixed effects of sow parity number and time (day after parturition). The sow parity numbers 2-4 (7.0 kg) had a higher colostrum yield than 1st parity sows (5.4 kg, P = 0.002) and parity 5-6 sows (5.9 kg, P = 0.025). No evidence of parity differences was observed on milk yield (P = 0.306). No effect of sow parity numbers on fat, protein and lactose in milk was observed. The dry matter in sow parity numbers 2-4 (19.8 g/100 g) had a tendency to be higher than sow parity number 1 (18.6 g/100 g, P = 0.107) and 5-6 (18.4 g/ 100 g, P = 0.053). In conclusion, sow parity number had an impact on colostrum yield in Danish Landrace × Yorkshire crossbred sows in a tropical climate but did not influence colostrum, milk composition and milk yield. Colostrum yield in Danish Landrace × Yorkshire crossbred sows was the highest in sow parity numbers 2-4.

Fatty acid profile of phospholipids and sphingomyelin in milk and regulation of sphingomyelin synthesis of mammary glands in cows receiving increasing levels of crushed sunflower seeds.

The objective of this study was to investigate the effect of increasing dietary supplementation of crushed sunflower seed (CSS) in the diet of dairy cows on the fatty acid (FA) composition of phospholipids and sphingomyelin in milk, and on mammary transcription of genes that are important for sphingomyelin de novo synthesis. Four groups of 6 cows received diets supplemented with CSS at 0% (control), or 5, 10, or 15% of dry matter for a 5-wk experimental period. Milk samples and mammary biopsies were collected at the end of the experiment. Phospholipid concentration in milk fat decreased linearly with CSS supplementation. Sphingomyelin concentration in milk fat was unaffected by CSS supplementation. Daily yield of phospholipids decreased linearly with CSS supplementation. Daily yield of sphingomyelin was not significantly affected. The CSS supplementation linearly increased the proportion of monounsaturated FA in milk phospholipids. The major isomer incorporated into phospholipids was C18:1 (n-9 cis), which showed a linear increase with CSS supplementation. The C22:0 proportion in sphingomyelin increased linearly with CSS supplementation and constituted between 15.2 to 25.4% of total FA in sphingomyelin. However, CSS supplementation linearly decreased C23:0 sphingomyelin. Mammary transcription of serine palmitoyl transferase, long chain subunit 1 and subunit 2, the rate-limiting enzymes in ceramide synthesis, showed a linear decrease with increasing CSS supplementation. In conclusion, the data showed that dietary supplementation of CSS linearly increased the proportion of unsaturated FA and monounsaturated FA in milk phospholipids with no effect on phospholipid concentration. In addition, CSS supplementation linearly decreased n-3 polyunsaturated fatty acid proportion in sphingomyelin. The results further showed that mammary transcription of important genes for sphingomyelin de novo synthesis is regulated by lipid supplementation.

Increased dietary protein for lactating sows affects body composition, blood metabolites and milk production.

Hyper-prolific sows nurse more piglets than less productive sows, putting a high demand on the nutrient supply for milk production. In addition, the high production level can increase mobilization from body tissues. The effect of increased dietary protein (104, 113, 121, 129, 139 and 150 g standardized ileal digestible (SID) CP/kg) on sow body composition, milk production and plasma metabolite concentrations was investigated from litter standardization (day 2) until weaning (day 24). Sow body composition was determined using the deuterium oxide dilution technique on days 3 and 24 postpartum. Blood samples were collected weekly, and milk samples were obtained on days 3, 10 and 17 of lactation. Litter average daily gain (ADG) peaked at 135 g SID CP/kg (P < 0.001). Sow BW and back fat loss reached a breakpoint at 143 and 127 g SID CP/kg (P < 0.001). Milk fat increased linearly with increasing dietary SID CP (P < 0.05), and milk lactose decreased until a breakpoint at 124 g SID CP/kg and 5.3% (P < 0.001) on day 17. The concentration of milk protein on day 17 increased until a breakpoint at 136 g SID CP/kg (5.0%; P < 0.001). The loss of body protein from day 3 until weaning decreased with increased dietary SID CP until it reached a breakpoint at 128 g SID CP/kg (P < 0.001). The body ash loss declined linearly with increasing dietary SID CP (P < 0.01), and the change in body fat was unaffected by dietary treatment (P=0.41). In early lactation (day 3 + day 10), plasma urea N (PUN) increased linearly after the breakpoint at 139 g SID CP/kg at a concentration of 3.8 mmol/l, and in late lactation (day 17 + day 24), PUN increased linearly after a breakpoint at 133 g SID CP/kg (P < 0.001) at a concentration of 4.5 mmol/l. In conclusion, the SID CP requirement for sows was estimated to 135 g/kg based on litter ADG, and this was supported by the breakpoints of other response variables within the interval 124 to 143 g/kg.

Effect of litter size, milk replacer and housing on production results of hyper-prolific sows.

The modern hyper-prolific sow gives birth to more piglets than she has functional teats (in the following called supernumerary piglets). The aim of the present study was (1) to investigate the production consequences of hyper-prolific sows rearing supernumerary piglets equal to the mean live-born litter size, and (2) investigate whether potential negative effects on survival and growth could be alleviated by providing access to milk replacer and/or providing easier access to the udder (by loose housing). At day 1 (D1) postpartum (pp), 93 litters were standardised to 14 or 17 piglets (LS14/LS17) after which no piglets were moved between sows leading to decreased litter size if piglets died. Litters were provided with or without milk replacer in milk cups (+MILK/-MILK), and sows were either crated or loose housed (CRATE/LOOSE) in a 2 × 2 × 2 factorial design. Piglet mortality was higher in LS17 compared to LS14 (P < 0.01; OR = 2.0), higher in -MILK compared to +MILK (P = 0.01; OR = 1.2) and higher in LOOSE compared to CRATE (P = 0.02; OR = 1.8). This study showed that sow rearing of supernumerary piglets while supplying with milk replacer can increase piglet survival. It also showed that early mortality before piglets learned to drink milk replacer posed a challenge using this automatic milk replacer system. An interaction between access to milk replacer and the standardised litter size D1 affected litter weight (P < 0.01) and piglet weight day 28 (D28) (P = 0.03). The highest litter weight D28 was found in LS17 +MILK (P < 0.01) but with a lower individual piglet weight than in LS14 -MILK. Piglet weight D28 was higher in LS14 -MILK compared to LS17 regardless of access to milk replacer. Heterogeneity in piglet weight within litters D28 was larger in LS17 (P = 0.03) but could be reduced with +MILK in CRATE (P < 0.01). No effects were found on sow weight loss and feed intake (P > 0.05). In conclusion, the results showed that sows cannot rear the supernumerary piglets without further management interventions to reduce mortality. Supplying supernumerary piglets equal to the mean live-born litter size of hyper-prolific sows with milk replacer can from results of this study be an alternative strategy to the use of nurse sows.

Transcriptional profiling of swine mammary gland during the transition from colostrogenesis to lactogenesis using RNA sequencing.

BACKGROUND: Colostrum and milk are essential sources of antibodies and nutrients for the neonate, playing a key role in their survival and growth. Slight abnormalities in the timing of colostrogenesis/lactogenesis potentially threaten piglet survival. To further delineate the genes and transcription regulators implicated in the control of the transition from colostrogenesis to lactogenesis, we applied RNA-seq analysis of swine mammary gland tissue from late-gestation to farrowing. Three 2nd parity sows were used for mammary tissue biopsies on days 14, 10, 6 and 2 before (-) parturition and on day 1 after (+) parturition. A total of 15 mRNA libraries were sequenced on a HiSeq2500 (Illumina Inc.). The Dynamic Impact Approach and the Ingenuity Pathway Analysis were used for pathway analysis and gene network analysis, respectively. RESULTS: A large number of differentially expressed genes were detected very close to parturition (-2d) and at farrowing (+ 1d). The results reflect the extraordinary metabolic changes in the swine mammary gland once it enters into the crucial phases of lactogenesis and underscore a strong transcriptional component in the control of colostrogenesis. There was marked upregulation of genes involved in synthesis of colostrum and main milk components (i.e. proteins, fat, lactose and antimicrobial factors) with a pivotal role of CSN1S2, LALBA, WAP, SAA2, and BTN1A1. The sustained activation of transcription regulators such as SREBP1 and XBP1 suggested they help coordinate these adaptations. CONCLUSIONS: Overall, the precise timing for the transition from colostrogenesis to lactogenesis in swine mammary gland remains uncharacterized. However, our transcriptomic data support the hypothesis that the transition occurs before parturition. This is likely attributable to upregulation of a wide array of genes including those involved in 'Protein and Carbohydrate Metabolism', 'Immune System', 'Lipid Metabolism', 'PPAR signaling pathway' and 'Prolactin signaling pathway' along with the activation of transcription regulators controlling lipid synthesis and endoplasmic reticulum biogenesis and stress response.

Effect of experimentally increased protein supply to postpartum dairy cows on plasma protein synthesis, rumen tissue proliferation, and immune homeostasis.

The effect of experimentally increasing the postpartum protein supply on plasma protein synthesis, rumen tissue proliferation, and immune homeostasis was studied using 8 periparturient Holstein cows in a complete randomized design. At calving, cows were assigned to abomasal infusion of water (CTRL) or casein (CAS) in addition to a lactation diet. Casein infusion was gradually decreased from 696 ± 1 g/d at +2 d relative to calving (DRTC) to 212 ± 10 g/d at +29 DRTC to avoid excessive supply. Synthesis rate of plasma proteins was measured at -14, +4, +15, and +29 DRTC by measuring [C]Phe isotopic enrichment in arterial plasma free Phe, total plasma proteins, and albumin after 3, 5, and 7 h of jugular ring[C]Phe infusion. Plasma volume was determined at +4 and +29 DRTC by dilution of a [I]BSA dose. Synthesis rate of tissue protein in biopsied rumen papillae was determined by measuring [C]Phe isotopic enrichment, and mRNA expression of selected genes was measured by real-time qPCR. Total and differential leukocyte counts were performed and immune responsiveness of monocytes was evaluated by tumor necrosis factor ɑ (TNFɑ) concentration on ex vivo whole blood stimulation with Escherichia coli lipopolysaccharide (LPS) and responsiveness of T-lymphocytes by interferon γ (IFNγ) concentration on stimulation with Staphylococcus aureus enterotoxin ß (SEB). Further, ELISA plasma concentrations of IgM, IgA, and IgG were determined. The DRTC affected the majority of investigated parameters as expected. The CAS treatment increased milk protein yield (P = 0.04), and tended to lower TNFɑ (P = 0.06), and lowered IFNγ (P = 0.03) responsiveness per monocyte and lymphocyte, respectively, compared with CTRL. Further, fractional synthesis rate of albumin was greater at +4 DRTC for CAS compared with CTRL but did not differ by +29 DRTC (interaction: P = 0.01). In rumen papillae, synthesis rate of tissue protein was greater for CAS compared with CTRL (P < 0.01) and mRNA expression of genes for cell proliferation tended to be or were greater for CAS compared with CTRL (P ≤ 0.07). In conclusion, increased postpartum protein supply seem to enhance vital body functions as interpreted from increased liver synthesis of albumin, increased rumen papillae proliferation, and stabilized the ex vivo inflammatory responsiveness of leukocytes. Further studies are needed to enlighten the importance of increased postpartum protein supply in periparturient cows.

Mammary nutrient uptake in multiparous sows fed supplementary arginine during gestation and lactation.

Arginine is the precursor for the synthesis of nitric oxide and may increase mammary plasma flow (MPF), which may in turn increase mammary nutrient uptake. Quantifying mammary nutrient uptake improves our understanding of mammary nutrient metabolism and may potentially allow identification of limiting nutrients for colostrum and milk production. Thus, the objectives of the present study were 1) to study the impact of 25 g/d of crystalline Arg (ARG) on MPF and uptake of nutrients by the mammary glands compared with an isonitrogenous supply of Ala (51 g/d; control [CON]) fed to a total of 8 sows from d 30 of gestation until weaning on d 28 of lactation and 2) to quantify mammary nutrient uptake in late gestation and in early and at peak lactation. Sows were surgically fitted with indwelling catheters on d 76 ± 2 SEM of gestation. -amino hippuric acid (AH) was infused (3.0 mmol/h) in the infusion catheter inserted in the mammary vein, initiated 1 h before the first blood sample at -10, -3, 3, and 17 d in milk (DIM). Blood samples were simultaneously drawn from catheters inserted in the femoral artery and the mammary vein, and the samples were collected in hourly intervals from 0.5 h before to 6.5 h after feeding. Sow milk production was assessed at 3 and 17 DIM. Arterial plasma concentrations of Arg and Ala were increased in ARG and CON sows, respectively ( < 0.01), whereas we did not succeed in detecting a greater MPF in ARG sows ( = 0.30). Arterial-venous differences ( = 0.03) and net mammary flux ( = 0.01) of Ala were increased in CON sows, while the net flux of most other metabolites ( > 0.05) was unaffected by treatment. The mammary extraction of all essential AA was below 13% in late gestation. The average mammary extraction of essential AA at peak lactation was greatest for Leu (51%), while the preprandial extraction was greatest for Lys (57%). The mammary carbon balance (input-output) was negative (-39 ± 12 mol C/d) in early lactation but almost balanced at peak lactation (-13 ± 14 mol C/d), suggesting that mammary fat depots contributed to milk synthesis. In conclusion, we failed to observe an increased MPF and mammary uptake of AA and energy metabolites in ARG-supplemented sows. The mammary extraction rate of essential AA indicated that AA were not limiting for the mammary glands in late gestation, while Lys and Leu appeared to be the 2 most limiting essential AA for milk production at peak lactation.

Dietary supplement rich in fiber fed to late gestating sows during transition reduces rate of stillborn piglets.

The beneficial effects of dietary fiber (DF) from a behavioral and welfare perspective have been thoroughly studied. However, data on the effects of DF on reproductive performance are scarce. Therefore, the aim of this study was to investigate the impact of increased DF supply during the last 2 wk of gestation on stillbirth rate, preweaning mortality, and total piglet mortality. A total of 644 sows were selected for the experiment from a commercial farm, and the sows were inseminated in weekly batches. Sows in the control group ( = 310) were fed according to the normal feeding strategy of the farm with a gestation diet until 1 wk before expected farrowing, then a transition diet until d 5 of lactation, and then a lactation diet until weaning. Sows in the treatment group ( = 334) were fed as the control group except that 280 g/d of the gestation diet (from d 102 to 108 of gestation) and 570 g/d of the transition diet (from d 109 of gestation until farrowing) was daily replaced with 350 and 700 g/d, respectively, of a DF-rich supplement. Both groups received isocaloric diets on a NE basis. The numbers of live-born and stillborn piglets as well as mortality of live-born piglets with presumed causes of death were recorded. The supplemented DF reduced the proportion of stillborn piglets from 8.8 to 6.6% ( < 0.001) and mortality of total born piglets from 22.3 to 19.9% ( = 0.004) but had no impact on preweaning mortality of the piglets ( = 0.21). Moreover, supplemented DF reduced the proportion of death due to poor viability ( < 0.001; 2.8 vs. 1.5% in the control and treatment groups, respectively) and prevalence of piglet diarrhea ( = 0.004; 0.7 vs. 0.3% in the control and treatment groups, respectively). Crushing, low birth weight, and poor viability were the top 3 contributors to preweaning mortality of live-born piglets, in descending order. In conclusion, the supplemented DF reduced the proportion of stillborn piglets and total piglet mortality as well as mortality due to poor viability and piglet diarrhea in lactation.

Impact of fat source and dietary fibers on feed intake, plasma metabolites, litter gain and the yield and composition of milk in sows.

Sow lactation diets often include fat sources without considering the impact on digestion, metabolism and performance. Fiber ingredients may reduce feed intake and are often completely excluded from lactation diets, although locally available ingredients may be cost-efficient alternatives to partly replace cereals in lactation diets. Thus, a standard lactation diet low in dietary fiber, and two high-fiber diets based on sugar beet pulp (SBP) or alfalfa meal (ALF) were formulated. The SBP diet was high in soluble non-starch polysaccharides (NSP), whereas ALF being high in insoluble NSP. Each diet was divided in three portions and combined with 3% soybean oil (SOYO), palm fatty acid distillate (PFAD), or glycerol trioctanoate (C8TG) as the dietary fat source. Equal amounts of metabolizable energy were fed to 36 second parity sows from day 105 of gestation and throughout lactation to study the impact on feed intake, plasma metabolites, milk production and litter performance. Backfat thickness and BW of sows were recorded on days 3, 17 and 28 of lactation; blood was sampled on days 3 and 17; milk samples were obtained on days 3, 10, 17 and 24 of lactation; and piglets were weighed on days 2, 7, 14, 21 and 28 of lactation. Litter gain and milk yield during late lactation were greater in sows fed C8TG or SOYO than in sows fed PFAD (P=0.05), whereas loss of BW (P=0.60) and backfat (P=0.70) was unaffected by fat source. Milk protein on days 3 and 10 of lactation were lower in C8TG and SOYO sows, than in PFAD sows (P<0.05). The lowest concentration of plasma lactate on day 3 (P<0.05) and plasma acetate on day 17 (P<0.05) was observed in C8TG sows. Milk yield was unaffected by fiber treatment (P=0.43), whereas milk protein concentration was lowest in ALF sows (P<0.05). Feed intake tended to be lower (P=0.09), and litter gain during the 3rd week of lactation was decreased (P<0.05) in SBP sows. In conclusion, performance was enhanced in SOYO and C8TG compared with PFAD sows, possibly associated with reduced energy intake in PFAD-fed sows. Furthermore, the SBP diet seemed to impair feed intake and litter gain at peak lactation, suggesting that effects of the dietary fiber fraction on energy intake determines the potential inclusion level of fiber-rich ingredients.

Technical note: Measurement of mammary plasma flow in sows by downstream dilution of mammary vein infused -aminohippuric acid.

The objectives of the present study were to design a method to estimate mammary plasma flow (MPF) in lactating sows using downstream dilution of -aminohippuric acid (AH) and to compare these estimates with MPF estimates based on specific AA as internal markers (MPF-AA). A permanent indwelling catheter was surgically implanted in the femoral artery, and another 2 were inserted in the right cranial mammary vein of 8 second- and third-parity sows on d 76 ± 2 SEM of gestation. On the 3rd and 17th days in milk, arterial and venous blood samples were drawn in hourly intervals from 0.5 h before until 6.5 h after feeding. The MPF in the right cranial mammary vein was measured by downstream dilution of infused AH (3.0 mmol/h). Total MPF-AH was calculated assuming that the measured flow constituted the flow from 5 out of 14 suckled glands on the basis of the anatomical structure of the mammary vascular system. Total MPF-AA was estimated on the basis of the output of the specific AA marker in milk and the arteriovenous differences of the marker as free AA in plasma, assuming a direct transfer of AA from plasma to milk protein. Total MPF-AH was 6,860 L/d in early lactation and increased to 8,953 L/d at peak lactation ( = 0.003). In early lactation, MPF-AA estimates were greater or tended to be greater (132% to 175%; < 0.10) than MPF-AH estimates for all internal markers, except Met (119%). Moreover, MPF-AH was correlated with MPF-AA only for MET as an internal marker ( = 0.74; = 0.03) in early lactation. In contrast, MPF-AH and MPF-AA estimates did not differ and were well correlated at peak lactation with the strongest correlation observed when Met ( = 0.84; = 0.009) and Phe + Tyr ( = 0.82; = 0.01) were used as the internal AA markers. Litter gain increased from d 3 to 17 of lactation (2.13 vs. 3.46 g/d; = 0.001) and was correlated with MPF-AH during lactation ( = 0.74; < 0.001), whereas no correlation between litter gain and MPF-AA was observed ( > 0.10). These results suggest that downstream dilution of infused AH and the AA methods are applicable methods to estimate MPF at peak lactation. The reason for the observed discrepancy in early lactation between MPF- AH and MPF-AA is not obvious but might be related to the rapid metabolic changes observed in early lactation. In conclusion, MPF measured by downstream dilution of mammary infused AH was higher at peak compared to early lactation, which the internal AA marker approach failed to show.

The effect of varying duration of water restriction on drinking behaviour, welfare and production of lactating sows.

Access to drinking water is essential for animal welfare, but it is unclear if temporary water restriction during the night represents a welfare problem. The aim of the present study was to investigate the effect of various durations of nightly restriction of water on thirst in loose housed lactating sows from day 10 to 28 of lactation. A total of 48 sows were deprived of water for either 0 h (n=12; control), 3 h (n=12; 0500 to 0800 h), 6 h (n=12; 0200 to 0800 h) or 12 h (n=12; 2000 to 0800 h). Control sows consumed 22% of their water intake during the night (2000 to 0800 h), whereas water consumption during this time was reduced to 13%, 7% and 0% in sows restricted for 3, 6 and 12 h. With increased duration of nightly water restriction a reduced latency to drink (26.8, 18.0, 5.3 and 6.7 min for 0, 3, 6 and 12 h sows; P<0.001) and an increased water intake during the 1st hour after water became accessible (2.1, 3.4, 4.7 and 5.6 l for 0, 3, 6 and 12 h sows; P<0.001) was seen. During the last 30 min before water became accessible more sows deprived of water investigated (0%, 50%, 75%,and 50% of 0, 3, 6 and 12 h sows; P<0.01) or forcefully manipulated (0%, 17%, 50% and 33% of 0, 3, 6 and 12 h sows; P<0.05) the water trough, suggesting frustration and a negative experience of thirst. When all signs of imminent water access were provided, but access was delayed by 25 min, a tendency for more of the sows deprived of water for 6 and 12 h to interact forcefully with the water trough was seen (22%, 18%, 42% and 67% of 0, 3, 6 and 12 h sows; P=0.09). Duration of water restriction did not affect water consumption on a 24-h basis, nursing behaviour or performance. In conclusion, behavioural indicators of thirst increased with increasing duration of nightly water restriction in lactating sows.

Impact of sow and litter characteristics on colostrum yield, time for onset of lactation, and milk yield of sows.

The aim of the present study was to estimate the concurrent impact of sow and litter characteristics on sow productivity. Sow productivity was defined as colostrum yield (CY), onset of lactation (the time point when milk secretion increased steeply, approximately 31 h postpartum), transition milk yield (MY; 36-60 h postpartum), and the mean MY in wk 1 to 4 of lactation. Therefore, the study investigated how factors related with sow nutrition, litter characteristics, farrowing characteristics, and composition of mammary secreta affected sow productivity. Data obtained from 5 previous sow experiments were used. The variables describing sow productivity were all defined as dependent variables and Pearson coefficient of correlation was used to examine relations among dependent variables. The results showed that CY was positively correlated with transition MY and MY in wk 1 and 2 of lactation (P < 0.05), and time for onset of lactation was positively correlated with transition MY (P < 0.05) but negatively correlated with MY in wk 1, 2, and 4 of lactation (P < 0.05). Multivariate regression analyses with a backward elimination approach were performed for each dependent variable to investigate relations with characteristics of sow nutrition, litter size, farrowing, and composition of mammary secreta (independent variables). Litter size was positively related with both CY and MY in wk 1 to 4 (P < 0.001). Milk protein concentration was negatively correlated with MY in all 4 wk (P < 0.01), which indicated that high yielding sows were unable to maintain milk protein synthesis during lactation. Additionally, mean intake of ME prepartum ( < 0.05) was included in the regression model for transition MY and the BW of the sow on d 3 was included in the regression model for MY in wk 1 ( P< 0.05). Except litter equlization, none of the observed independent variables were related with time for onset of lactation. In conclusion, when maximizing sow productivity in the future, it may be rewarding to pay attention to sow productivity in the colostrum period and around time for onset of lactation, and special attention should be given to dietary supplies of protein and essential AA.

Determination of protein and amino acid requirements of lactating sows using a population-based factorial approach.

Determination of appropriate nutritional requirements is essential to optimize the productivity and longevity of lactating sows. The current recommendations for requirements do not consider the large variation between animals. Therefore, the aim of this study was to determine the amino acid recommendations for lactating sows using a stochastic modeling approach that integrates population variation and uncertainty of key parameters into establishing nutritional recommendations for lactating sows. The requirement for individual sows was calculated using a factorial approach by adding the requirement for maintenance and milk. The energy balance of the sows was either negative or zero depending on feed intake being a limiting factor. Some parameters in the model were sow-specific and others were population-specific, depending on state of knowledge. Each simulation was for 1000 sows repeated 100 times using Monte Carlo simulation techniques. BW, back fat thickness of the sow, litter size (LS), average litter gain (LG), dietary energy density and feed intake were inputs to the model. The model was tested using results from the literature, and the values were all within ±1 s.d. of the estimated requirements. Simulations were made for a group of low- (LS=10 (s.d.=1), LG=2 kg/day (s.d.=0.6)), medium- (LS=12 (s.d.=1), LG=2.5 kg/day (s.d.=0.6)) and high-producing (LS=14 (s.d.=1), LG=3.5 kg/day (s.d.=0.6)) sows, where the average requirement was the result. In another simulation, the requirements were estimated for each week of lactation. The results were given as the median and s.d. The average daily standardized ileal digestible (SID) protein and lysine requirements for low-, medium- and high-producing sows were 623 (CV=2.5%) and 45.1 (CV=4.8%); 765 (CV=4.9%) and 54.7 (CV=7.0%); and 996 (CV=8.5%) and 70.8 g/day (CV=9.6%), respectively. The SID protein and lysine requirements were lowest at week 1, intermediate at week 2 and 4 and the highest at week 3 of lactation. The model is a valuable tool to develop new feeding strategies by taking into account the variable requirement between groups of sows and changes during lactation. The inclusion of between-sow variation gives information on safety margins when developing new dietary recommendations of amino acids and protein for lactating sows.

Mechanistic model to predict colostrum intake based on deuterium oxide dilution technique data and impact of gestation and prefarrowing diets on piglet intake and sow yield of colostrum.

The aims of the present study were to quantify colostrum intake (CI) of piglets using the D2O dilution technique, to develop a mechanistic model to predict CI, to compare these data with CI predicted by a previous empirical predictive model developed for bottle-fed piglets, and to study how composition of diets fed to gestating sows affected piglet CI, sow colostrum yield (CY), and colostrum composition. In total, 240 piglets from 40 litters were enriched with D2O. The CI measured by D2O from birth until 24 h after the birth of first-born piglet was on average 443 g (SD 151). Based on measured CI, a mechanistic model to predict CI was developed using piglet characteristics (24-h weight gain [WG; g], BW at birth [BWB; kg], and duration of CI [D; min]: CI, g=-106+2.26 WG+200 BWB+0.111 D-1,414 WG/D+0.0182 WG/BWB (R2=0.944). This model was used to predict the CI for all colostrum suckling piglets within the 40 litters (n=500, mean=437 g, SD=153 g) and was compared with the CI predicted by a previous empirical predictive model (mean=305 g, SD=140 g). The previous empirical model underestimated the CI by 30% compared with that obtained by the new mechanistic model. The sows were fed 1 of 4 gestation diets (n=10 per diet) based on different fiber sources (low fiber [17%] or potato pulp, pectin residue, or sugarbeet pulp [32 to 40%]) from mating until d 108 of gestation. From d 108 of gestation until parturition, sows were fed 1 of 5 prefarrowing diets (n=8 per diet) varying in supplemented fat (3% animal fat, 8% coconut oil, 8% sunflower oil, 8% fish oil, or 4% fish oil+4% octanoic acid). Sows fed diets with pectin residue or sugarbeet pulp during gestation produced colostrum with lower protein, fat, DM, and energy concentrations and higher lactose concentrations, and their piglets had greater CI as compared with sows fed potato pulp or the low-fiber diet (P<0.05), and sows fed pectin residue had a greater CY than potato pulp-fed sows (P<0.05). Prefarrowing diets affected neither CI nor CY, but the prefarrowing diet with coconut oil decreased lactose and increased DM concentrations of colostrum compared with other prefarrowing diets (P<0.05). In conclusion, the new mechanistic predictive model for CI suggests that the previous empirical predictive model underestimates CI of sow-reared piglets by 30%. It was also concluded that nutrition of sows during gestation affected CY and colostrum composition.

Energy and nutrient deposition and excretion in the reproducing sow: model development and evaluation.

Air and nutrient emissions from swine operations raise environmental concerns. During the reproduction phase, sows consume and excrete large quantities of nutrients. The objective of this study was to develop a mathematical model to describe energy and nutrient partitioning and predict manure excretion and composition and methane emissions on a daily basis. The model was structured to contain gestation and lactation modules, which can be run separately or sequentially, with outputs from the gestation module used as inputs to the lactation module. In the gestating module, energy and protein requirements for maintenance, and fetal and maternal growth were described. In the lactating module, a factorial approach was used to estimate requirements for maintenance, milk production, and maternal growth. The priority for nutrient partitioning was assumed to be in the order of maintenance, milk production, and maternal growth with body tissue losses constrained within biological limits. Global sensitivity analysis showed that nonlinearity in the parameters was small. The model outputs considered were the total protein and fat deposition, average urinary and fecal N excretion, average methane emission, manure carbon excretion, and manure production. The model was evaluated using independent data sets from the literature using root mean square prediction error (RMSPE) and concordance correlation coefficients. The gestation module predicted body fat gain better than body protein gain, which was related to predictions of body fat and protein loss from the lactation model. Nitrogen intake, urine N, fecal N, and milk N were predicted with RMSPE as percentage of observed mean of 9.7, 17.9, 10.0, and 7.7%, respectively. The model provided a framework, but more refinements and improvements in accuracy of prediction (particularly urine N) are required before the model can be used to assess environmental mitigation options from sow operations.

Neonatal piglet survival: impact of sow nutrition around parturition on fetal glycogen deposition and production and composition of colostrum and transient milk.

Piglet survival is a major problem, especially during the first 3 days after birth. Piglets are born deficient of energy, but at the same time they have a very high energy requirement because of high physical activity, high need for thermoregulation (because of their lean body with low insulation) and high heat production in muscle tissues. To be able to survive, newborn piglets may rely upon three different sources of energy, namely, glycogen, colostrum and transient milk, which orchestrate to cover their energy requirements. Piglets are born with limited amounts of energy in glycogen depots in the liver and muscle tissues and these depots are sufficient for normal activity for ∼16 h. Intake and oxidation of fat and lactose from colostrum must supply sufficient amount of energy to cover at least another 18 h until transient milk becomes available in the sow udder ∼34 h after the first piglet is born. Selection for large litters during the last two decades has challenged piglets even further during the critical neonatal phase because the selection programs indirectly decreased birth weight of piglets and because increased litter size has increased the competition between littermates. Different attempts have been made to increase the short-term survival of piglets, that is, survival until day 3 of lactation, by focusing on improving transfer of vital maternal energy to the offspring, either in utero or via mammary secretions. Thus, the present review addresses how sow nutrition in late gestation may favor survival of newborn piglets by increasing glycogen depots, improving colostrum yield or colostrum composition, or by increasing production of transient milk.

Intrauterine growth restricted piglets defined by their head shape ingest insufficient amounts of colostrum.

The increasing litter sizes of modern pig breeds have led to a significant number of piglets that are born undersized ("small" piglets) and some have been exposed to different degrees of intrauterine growth restriction (IUGR). The aim of this study was to investigate the physiology and capability to ingest colostrum of these small piglets, suffering from various degrees of IUGR, to see if their IUGR score could be a useful tool for easy identification of piglets in need of intervention in the colostrum period. Piglets were classified at birth based on head morphology. Piglets were classified either "normal," "mildly IUGR" (m-IUGR), or "severe IUGR" (s-IUGR), based on head morphology. Blood samples were collected at birth and at 24 h, and colostrum intake during two 12-h periods and blood metabolites at 0 and 24 h were measured. At 24 h, piglets weighing <900 g at birth and the median piglet in birth order were sacrificed, and organ weights and hepatic glycogen were measured. Overall, there was an influence of the piglets' classification on most characteristics, with normal piglets having a greater colostrum intake between 0 and 12 h (P < 0.001) and between 12 and 24 h (P < 0.05), and higher birth weight, crown rump length, body mass index, and ponderal index (P < 0.001), and a tendency toward a higher vitality score (P < 0.069) than s-IUGR piglets. There was a time × IUGR interaction, with plasma glucose levels being lowered (P < 0.001) and lactate levels elevated (P < 0.001) in s-IUGR piglets at 24 h compared with normal and m-IUGR piglets. Some differences were found in electrolytes; sodium plasma concentrations were greatest for normal piglets (P < 0.05) and highest at 0 h (P < 0.05). At 24 h of age, s-IUGR piglets had a higher heart (P < 0.001) and brain percentage (P < 0.001), and a lower liver percentage (P < 0.001) relative to body weight, compared with normal piglets. In addition, s-IUGR piglets had less hepatic glycogen than m-IUGR piglets and normal piglets. The present study showed that the physiology of piglets in the colostrum period was affected by IUGR status at birth and their intermediary metabolism was altered due to different colostrum intakes. Furthermore, it was demonstrated that the head shape of newborn piglets is a good selection criteria for identifying piglets that need oral supplementation during the neonatal stage.

Impact of feeding and post prandial time on plasma ketone bodies in sows during transition and lactation.

Two experiments were conducted with the aim of studying how dietary fat source, reproductive stage (Exp. 1), and diurnal variation (Exp. 2) affect plasma ketone bodies in sows. In Exp. 1, 40 second-parity sows were fed 1 of 5 lactation diets from 7 d prepartum until 28 d postpartum, with low or high levels (3% or 8%) of dietary fats with different proportions of medium- and long-chain fatty acids. Blood was obtained by jugular venipuncture on d 3 and 7 prepartum, and d 1, 10, 17, and 28 postpartum, and concentrations of plasma beta-hydroxy butyric acid (BHBA), acetoacetate + acetone (AcAc+Ac), glucose, NEFA, lactate, acetate, and butyrate were determined. For 4 out of 5 treatments, plasma BHBA decreased slightly, whereas plasma AcAc+Ac remained stable. However, plasma BHBA (P < 0.01) and AcAc+Ac (P < 0.001) doubled after d 10 of lactation in sows fed 4% octanoic acid and 4% fish oil diet (4+4% FO; P < 0.001), compared with earlier in lactation (P < 0.001). Plasma AcAc+Ac was positively related to BHBA (P < 0.01), glucose (P < 0.05), and butyrate (P < 0.001), and negatively related to the acetate:butyrate ratio (P < 0.001). In addition, plasma BHBA was positively related to lactate (P < 0.01), acetate, and butyrate (P < 0.05). In Exp. 2, diurnal variations of plasma metabolites were studied in 5 sows sampled every second hour from a jugular catheter throughout a 24-h period on d 5 and 17 of lactation and analyzed as in Exp. 1. In addition, milk and urine samples were collected and analyzed for BHBA and AcAc+Ac. No diurnal variations in plasma BHBA or AcAc+Ac were observed and plasma AcAc+Ac was unchanged from d 5 to 17 of lactation (3.7 µM), whereas BHBA declined from 58 µM on d 5 of lactation to 52 µM on d 17 of lactation (P < 0.05). Minor amounts of AcAc+Ac were found in urine (8.6 µM) and this was not affected by days in milk, whereas the content of AcAc+Ac in milk and BHBA in milk and urine were less than the detection limit in 4 of 5 sows. In conclusion, dietary fat source affected plasma concentrations of ketone bodies, but the concentrations were much less than normally observed in dairy cows and, therefore, primary ketosis does not appear to be a major problem in sows. In addition, this study indicates that the intermediary metabolism of sows was challenged when sows were exposed to high fat diets in late gestation.

Milk production in sows from a teat in second parity is influenced by whether it was suckled in first parity.

The impacts of a teat being suckled or not in first parity on its development, gene expression, and milk yield in the next parity were studied. Forty-seven first-parity sows (Sus scrofa) were divided into 2 groups: i) the same teats suckled in 2 subsequent lactations (controls, CTL; n = 22); and ii) different teats suckled in 2 subsequent lactations (treated, TRT; n = 25). In the first lactation, over half of the teats (Teats 1, 2, 5, 6, and 7 from 1 side of the udder, and Teats 3, 4, and 7 from the other side) were sealed with tape so that they were nonfunctional. During the next lactation, the CTL group had the same teats sealed as in the first lactation, whereas the opposite teats were sealed for the TRT group. In both parities, litters were standardized to 7 piglets around birth and to 6 piglets (1 piglet per available teat) at 48 h postpartum. During the second lactation, piglets were weighed at birth and on d 2, 4, 7, 14, 21, 35, and 56 postpartum. Weaning was at 17 ± 1 d of age. Behavioral measures were obtained (using 24-h video recording) on d 3 and d 10 of lactation on 15 sows per treatment to evaluate satiety of piglets, using aggressiveness and nursing behavior as indicators. At weaning in the second lactation, 16 sows per treatment were slaughtered and 4 functional mammary glands were collected for compositional analyses and parenchyma from 2 nonfunctional glands was collected to measure mRNA abundance for selected genes. Piglets from CTL sows weighed 1.12 kg more than piglets from TRT sows (P < 0.05) on d 56, and functional mammary glands from CTL sows contained more parenchymal tissue, more DNA, and more RNA (P < 0.01) than those from TRT sows. The relative mRNA abundance of prolactin in parenchymal tissue tended to be greater in CTL than TRT sows (P < 0.10). Behavioral measures indicated a greater hunger level for piglets using teats that were not previously suckled. Current findings clearly show that teats that were suckled in first lactation produce more milk and have a greater development in the second lactation than nonsuckled teats.