509 Late-Breaking: Effect of a Sensory Additive on Sow Reproductive Performance

The addition of a sensory additive to sow diets during the summer improved feed intake during lactation, and litter performance. The aim of this study was to evaluate the impact of the sensory additive on sow lactation performance during cooler temperatures. Three consecutive groups (n = 61 total) of sows were farrowed during winter (October, December and January). Sows were weighed, and back fat depth was measured, at 110 d of gestation prior to entering the lactation room, and again at weaning. The sows were sorted by parity, and then allotted by BW at d 110 to Control or 0.075% sensory additive (Luctamax® SowVive, Lucta S.A., Spain). Experimental diets were offered upon entry to the lactation room and fed through weaning. Feed disappearance was recorded every three days. Sows were fed 2.72 kg/head/day until farrowing, and then allowed to eat ad libitum from 24 hours post-farrowing until weaning. Data were analyzed using the PROC MIXED procedure of SAS as an RCBD with treatment as the fixed effect and group as a random effect. No differences were observed on sows feed intake (P > 0.4), 10th rib backfat thickness change (P = 0.632) and body weight change from d 110 of gestation to weaning (P = 0.65, Table 1). Sows fed the sensory additive lowered preweaning mortality by 4.9% (P = 0.051), and weaned an additional 1.42 piglets (P = 0.026) with similar weaning weights (P = 0.86) when compared to control. In conclusion, in the current study, lactation diets supplemented with a sensory additive improved litter performance and helped maintain sow body condition.

Identification of SNPs and Candidate Genes for Milk Production Ability in Yorkshire Pigs

Sow milk production ability is an important limiting factor impacting suboptimal growth and the survival of piglets. Through pig genetic improvement, litter sizes have been increased. Larger litters need more suckling mammary glands, which results in increased milk from the lactating sow. Hence, there is much significance to exploring sow lactation performance. For milk production ability, it is not practical to directly measure the milk yield, we used litter weight gain (LWG) throughout sow lactation as an indicator. In this study, we estimated the heritability of LWG, namely, 0.18 ± 0.07. We then performed a GWAS, and detected seven significant SNPs, namely, Sus scrofa Chromosome (SSC) 2: ASGA0010040 (p = 7.73E-11); SSC2:MARC0029355 (p = 1.30E-08), SSC6: WU_10.2_6_65751151 (p = 1.32E-10), SSC7: MARC0058875 (p = 4.99E-09), SSC10: WU_10.2_10_49571394 (p = 6.79E-08), SSC11: M1GA0014659 (p = 1.19E-07), and SSC15: MARC0042106 (p = 1.16E-07). We performed the distribution of phenotypes corresponding to the genotypes of seven significant SNPs and showed that ASGA0010040, MARC0029355, MARC0058875, WU_10.2_10_49571394, M1GA0014659, and MARC0042106 had extreme phenotypic values that corresponded to the homozygous genotypes, while the intermediate values corresponded to the heterozygous genotypes. We screened for flanking regions ± 200 kb nearby the seven significant SNPs, and identified 38 genes in total. Among them, 28 of the candidates were involved in lactose metabolism, colostrum immunity, milk protein, and milk fat by functional enrichment analysis. Through the combined analysis between 28 candidate genes and transcriptome data of the sow mammary gland, we found nine commons (ANO3, MUC15, DISP3, FBXO6, CLCN6, HLA-DRA, SLA-DRB1, SLA-DQB1, and SLA-DQA1). Furthermore, by comparing the chromosome positions of the candidate genes with the quantitative trait locus (QTLs) as previously reported, a total of 17 genes were found to be within 0.86–94.02 Mb of the reported QTLs for sow milk production ability, in which, NAV2 was found to be located with 0.86 Mb of the QTL region ssc2: 40936355. In conclusion, we identified seven significant SNPs located on SSC2, 6, 7, 10, 11, and 15, and propose 28 candidate genes for the ability to produce milk in Yorkshire pigs, 10 of which were key candidates.

241 Evaluation of a DFM and OA, Alone or in Combination, on Sow Reproductive and Litter Growth Performance

Forty-seven sows and their progeny were used to determine if feeding gestating and lactating sows a Bacillus licheniformis direct-fed microbial (DFM), an organic acid blend of medium chain and short chain fatty acids (OA), or in combination improves sow lactation feed and water intake, litter growth, and subsequent reproductive performance. On approximately d80 of gestation, sows were fed one of four diets in a 2 x 2 factorial design: 1) gestation control (CON; 0.55% SID Lysine), 2) CON with DFM (1.6x109 CFU/kg of complete feed), 3) CON with 0.4% OA, 4) CON with both DFM and OA. Dietary treatments were also fed throughout lactation (1.00% SID Lysine) starting on approximately d112 of gestation when sows entered farrowing facility. There was a tendency (P = 0.079) for DFM to decrease the amount of sow body weight loss in lactation by approximately 6% compared to sows not consuming the DFM, likely related to DFM sows numerically (P = 0.124) consuming 8.4% more feed during d7-14 of lactation. Sows fed the OA diets had fewer mummies/litter (P = 0.038) compared to diets not containing OA. Sows fed diets with the DFM gave birth to lighter pigs born alive (P = 0.003) compared to non-DFM fed sows, and a tendency for an interaction (P = 0.092) existed where feeding OA+DFM lessened the decrease in born alive BW. There was an interaction tendency (P = 0.133) where sows fed DFM returned to estrus 22 hours sooner than CON, but only 8 hours sooner when sows were fed the OA+DFM diet. In conclusion, feeding a Bacillus licheniformis DFM to sows may decrease pig born alive weight but reduce sow BW loss through 6.4% more lactation feed intake, quickening the return to estrus. Feeding the OA alone or in combination did not improve sow reproductive and litter growth performance in this study, and may require a larger sample size.

Impact of Sow Transition Diet and Genetic Line on Sow Reproduction Under Heat Stress Conditions

The objective was to evaluate a sow transition diet and genetic line for farrowing duration and sow lactation characteristics. One batch of second parity sows (n = 78) were farrowed at the NCDA Tidewater Research Station in July. Sows consisted of two genetic lines, one selected since 2012 for young age at puberty and the other selected for old age at puberty. From day 109 of gestation until day 3 of lactation, sows were fed either 2.73 kg of a corn-soy lactation diet (3322 Kcal ME/kg, 0.99% SID lysine) once per day or 1.36 kg twice per day of a transition diet (3489 Kcal/kg, 0.71 SID lysine). The transition diet contained 45% wheat middlings, 8% added soybean oil, 3000 FTU/kg of phytase and 500 ppm zinc sulfate. Continuous traits and categorical traits were analyzed in SAS using linear models and chi-square tests, respectively. Results showed sows fed the transition diet farrowed numerically faster (P = 0.18) than those receiving the lactation diet (3:04 vs. 3:47). Transition diet fed sows tended (P = 0.10) to have a shorter wean-to-estrus interval than sows fed the lactation diet (5.27 vs. 5.69 days). Sows from the young puberty genetic line tended (P = 0.07) to have a greater average daily feed intake during lactation when compared to old puberty line females (4.92 vs. 4.71 kg). Young puberty sows also had a greater (P = 0.03) percentage of females exhibiting estrus by day 7 after weaning when compared to the old puberty genetic line (80 vs. 57%). No differences (P = 0.39 to 0.87) were detected between diets or genetic lines for stillborn piglet percentage, average piglet birth weight, average piglet weaning weight or litter size at weaning. Results suggest young puberty sows are more likely to return to estrus under the conditions of this study.

PSVIII-14 Impact of altering Lys:energy ratio during gestation on offspring post-wean growth performance

Lysine and energy supply in gestation can influence preweaning mortality and sow lactation feed intake but little data exists for the impact on offspring post-weaning performance. A study evaluated the effects of dietary Lys:energy during gestation on offspring performance from weaning until market. Both primiparous and multiparous females (n=59 in 2 groups) were blocked by parity, balanced by weight and allotted to one of three gestation feeding regimens: 1.50 g SID Lys/Mcal ME (Control), 1.50 g SID Lys/Mcal ME from d2–89 and 2.11 g SID Lys/Mcal ME from d90–110 d of gestation (PF1) and 1.25, 1.07, and 0.88 g SID Lys/Mcal ME from d2–89 for gilts, parity 1 and parity 2+, respectively and 2.11 g SID Lys/Mcal ME from d90–110 d of gestation (PF2). Offspring (n=682) were weaned into 40 pens by maternal treatment (n=13-15 pigs/pen, mixed gender/pen). Pen feed disappearance and individual pig weights were determined at least once each month until market. Animals were marketed by a technician blinded to treatment; to account for potential marketing bias, adjusted d130 weight was calculated. Data were analyzed as a randomized complete block with means separation using Scheffe’s adjustment. The offspring of Control sows had decreased BW at weaning (P < 0.001) versus PF1 offspring and Control offspring had decreased BW (P = 0.001) compared to both PF1 and PF2 at d7 post-weaning. Despite minimal differences in ADG, ADFI, or G:F between treatments, PF2 offspring were heavier (P = 0.02) at market and adjusted d130 weight than Control pigs. While PF1 offspring had similar BW at market than Controls, they spent fewer (138.2 vs. 142.7; P = 0.009) days on feed than Control pigs due to the aforementioned marketing bias. Altered Lys:energy ratio in a single gestation cycle improved offspring post-wean performance.

270 Efficacy of Bacillus subtilis and Bacillus licheniformis (BioPlus2B®) on sow lactation performance, litter growth, nursery performance and health of pigs challenged with PRRS virus post-wean

Probiotics have been shown to support normal growth and immune function in pigs in challenging environments. A commercial probiotic (BioPlus2B®) containing two microbial species (Bacillus subtilis and Bacillus licheniformis) was tested to determine its effect on lactation of sows, pre-weaning performance of litters, and post-weaning performance of pigs challenged with PRRS virus. Sows (n = 120) were fed to meet or exceed NRC 2018 requirements and divided into two treatment groups: control and BioPlus2B®. BioPlus2B® was fed daily at an equivalent of 1.6 x 109CFU/kg and daily feed intake was recorded. Production practices were closely monitored in order to reduce the risk of bacteria cross-contamination between treatment groups and to maintain responsible animal welfare practices. By 24 hours post-farrow, piglets were cross-fostered within treatment group and subsequently weighed. They were weighed again on day 17. Upon weaning at approximately 21 days, piglets from each treatment group were separated into one of three BSL2 rooms and allocated to one of 36 pens per treatment for a 28-day growth study. The treatment group was fed BioPlus2B® daily at 1.1 x 109CFU/kg. At seven days post-wean, pigs were infected IM with 2 x 103.5 TCID 50 of the PRRS virus. Sow, litter, or pen was considered the experimental unit except for birth and wean weights. Sows that consumed BioPlus2B® daily birthed heavier piglets, consumed more feed throughout lactation, and tended to wean heavier pigs than Control sows. Pigs that consumed BioPlus2B® post-wean resulted in greater ADG, ADG:ADFI, and reduced mortality after PRRS infection. Data is expressed as least square means ±SEM. Values at P< 0.05 are considered significantly different while values between 0.05< P≤0.10 are considered a trend. In summary, feeding a defined probiotic supports optimal performance of sows and litters and effective immune responses of pigs challenged with respiratory disease.

272 Hybrid rye may replace up to 75% of the corn in diets for gestating and lactating sows without negatively impacting sow and piglet performance

An experiment was conducted to test the hypothesis that hybrid rye can replace corn in gestation and lactation diets without negatively affecting sow and litter performance. For gestation and lactation, a corn-soybean meal control diet and 3 additional diets in which hybrid rye replaced 25, 50, or 75% of corn were formulated. Sows were randomly allotted by parity to treatments, with 45 replicate sows per treatment. Sows were individually housed for the duration of the experiment. Sow BW were recorded on d 7 and d 105 of gestation, as well as within 24 h after farrowing and on the day of weaning (approximately d 20 of lactation). Number and weights of live born, still born, and mummified piglets were determined within 24 h of farrowing. Data related to piglet mortality were analyzed using SAS Proc Glimmix with binomial distribution, whereas all other data were analyzed using Proc Mixed. The statistical models included the fixed effects of diet and parity. Diet did not influence sow BW or sow ADG at any point in the experiment (Table 1). Diet did not affect number or weights of total, live, or still born pigs, but there was an increase and then a reduction in the number of pigs weaned, litter wean weight, and litter ADG as the inclusion of hybrid rye in the diets increased (quadratic, P < 0.05). Piglet mortality, as well as the proportion of piglets crushed by sows, tended (P < 0.10) to be quadratically reduced as hybrid rye was added to the diet. In conclusion, replacing corn with hybrid rye in gestation and lactation diets had no effect on sow BW changes nor on number or birthweights of piglets, and overall, diets with 25% and 50% corn replacement rate with rye resulted in improved sow lactation performance.

Characterization and Comparative Analysis of Transcriptional Profiles of Porcine Colostrum and Mature Milk Across Multiple Parities

BackgroundThe expression of genes and their regulation during lactation in swine is not well-understood. In order to gain a better understanding of genes and pathways involved in sow lactation, total RNA from colostrum and mature milk samples were sequenced from 65 sows across four parities. A stringent bioinformatic pipeline was used to identify and characterize 44,234 transcripts. ResultsThe 44,234 identified transcripts included 41,875 previously annotated transcripts and 2,359 novel transcripts. Differential gene expression analysis was conducted using a generalized linear model coupled with the Lancaster method for P-value aggregation across transcripts. In total, 1,900 differentially expressed genes (DEG) were identified for the milk type main effect, and 373 DEG were identified for the milk type x parity interaction. Several gene ontology (GO) terms related to immune response were significant for the milk type main effect, supporting the widely-accepted hypothesis that immunoglobulins and immune cells are transferred to the neonate via colostrum.ConclusionsThis is the first study to perform global transcriptome analysis from whole milk samples in sows from multiple parities. Our results provide important information and insight into synthesis of milk proteins and innate immunity and potential targets for future improvement of swine lactation and piglet development.

Impact of sow lactation feed intake on the growth and suckling behavior of low and average birthweight pigs to 10 weeks of age

Improved genetics in commercial pig production have resulted in larger litter sizes. However this has increased the prevalence of compromised pigs exhibiting inferior birthweights, weaning weights, and lifetime performance. This study aimed to determine the effects of increased sow lactation feed intake on growth of low and average birthweight piglets until 10 wk of age. Low (Low BW; <1 kg) and average (Av BW; 1.3–1.7 kg) birthweight animals were reared in uniformly weighted litters comprising 14 piglets on a foster mother offered either a low (Low FA; max 7.5 kg/d) or high (High FA; max 11 kg/d) feed allowance over a 28- ± 1-d lactation. Piglet performance was monitored from birth until 10 wk of age. Sows offered a High FA consumed 42.4 kg more feed on average than those offered Low FA, resulting in a greater derived milk yield (P < 0.05). Animals of Av BW remained heavier than Low BW pigs throughout the trial (P < 0.05). Piglets reared by High FA sows were heavier at weeks 3, 4, 5, and 7 (P < 0.05) but not week 10 (P > 0.05). Growth rate of piglets relative to their birthweight was significantly greater for Low BW piglets than those of Av BW during lactation (P < 0.001). Piglets reared by sows offered a High FA expressed greater relative growth preweaning (P < 0.05); however, postweaning relative growth for piglets reared on sows offered a Low FA was greater (P < 0.05) suggesting compensatory growth. Neither birthweight nor sow feed allowance significantly affected preweaning mortality (P > 0.05). However, Low BW animals on sows with a High FA recorded half the preweaning mortality of Low BW pigs on sows with a Low FA. During week 1 of lactation, Av BW litters recorded a greater total suckling duration compared to Low BW litters (P < 0.05) but there was no difference in suckling frequency (P > 0.05). During week 3 of lactation, High FA litters displayed a significantly lower suckling frequency (P < 0.05) yet a greater total suckling duration (P < 0.001). Average daily gain was greater for Av BW pigs during weeks 4–7 (P < 0.001) but no difference was recorded between weeks 7 and 10 (P > 0.05). Average daily feed intake was greater for Av BW pigs throughout the nursery period (P < 0.05) but feed–conversion ratio did not differ compared to Low BW pens (P>0.05). In conclusion, offering sows a High FA increased weaning weight of all animals; however, birthweight was the major determinant of postweaning performance.

95 The effect of incremental dietary energy density from 13.8 to 15.9 MJ DE/kg on piglet vitality and growth to weaning

Genetic selection for hyper-prolificacy in sows has resulted in a significant increase in the number of piglets born alive per litter; however, a consequence has been a reduction in piglet vitality and survival. Increasing lactation dietary energy density can increase sow energy intake and the survival and growth of piglets from large litters. The objective of this experiment was to investigate the effect of increasing sow lactation dietary energy density on piglet vitality and growth to weaning. At d 108 of gestation, sows (n = 115) were blocked by parity, BW and backfat, and randomly assigned to one of four energy density diets until weaning; 13.8, 14.5, 15.2 and 15.9 MJ DE/kg. At birth, body temperature, IUGR traits and muscle tone were recorded in piglets. At 24 h, piglet body temperature and blood glucose concentration were recorded. Piglets were weighed throughout lactation. Data were analysed using the mixed models procedure in SAS (v.9.4). Average daily energy intake was highest for sows fed 15.9 MJ DE/kg compared to sows fed 13.8, 14.5 and 15.2 MJ DE/kg (115.1 v 98.92, 102.33, 107.83MJ DE/d±1.51; P < 0.01). Piglets from sows fed 13.8 and 15.9 MJ DE/kg were more likely to have more IUGR traits and a higher muscle tone score, respectively, compared with all other treatments (P < 0.01). The 24 h body temperature was higher for piglets from sows fed 13.8 and 15.2 MJ DE/kg than piglets from sows fed 15.9 MJ DE/kg (35.47 and 35.48 v 35.22⁰C±0.05; P < 0.01). Glucose concentration was higher for piglets from sows fed 14.5 MJ DE/kg than piglets from sows fed 15.9 MJ DE/kg (4.70 v 4.15mg/ml±0.14; P < 0.01). Litter weaning weight was heaviest for sows fed 13.8 MJ DE/kg compared with sows fed 14.5 MJ DE/kg (92.90 v 84.97kg±1.59; P < 0.01). In conclusion, feeding lactating sows 15.9 MJ DE/kg increased daily sow energy intake and improved piglet development.