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During the last decade, sow mortality due to pelvic organ prolapse (POP) has increased. To better understand the biology associated with POP, sows were phenotypically assessed and assigned a perineal score (PS) based on presumed POP risk and categorized as PS1 (low), PS2 (moderate), or PS3 (high). The study objective was to identify changes in sow vaginal microbiota that may be associated with POP. The hypothesis is that vaginal microbiota differs between sows with variable risk for POP, and changes in microbiota during late gestation exist between sows with differing risk. Of the 2864 sows scored during gestation week 15, 1.0, 2.7, and 23.4% of PS1, PS2, and PS3 sows, respectively, subsequently experienced POP. Vaginal swabs subjected to 16S rRNA gene sequencing revealed differences in community composition (Bray–Curtis; P< 0.05) and individual operational taxonomic unit (OTU) comparisons between vaginal microbiota of PS1 and PS3 sows at gestation week 15. Further, differences (P< 0.05) in community composition and OTUs (Q< 0.05) were observed in PS3 sows that either did or did not subsequently experience POP. Differences in community structure (alpha diversity measurements; P< 0.05), composition (P< 0.05), and OTUs (Q< 0.05) were observed in gestation week 12 sows scored PS1 compared to week 15 sows scored PS1 or PS3, suggesting that sow vaginal microbiota shifts during late gestation differently as POP risk changes. Collectively, these data demonstrate that sows with greater POP risk have unique vaginal microflora, for which a better understanding could aid in the development of mitigation strategies.

In the U.S. swine industry, feeding programs are focused on using feed ingredients that are easily digestible and cost effective. With the predicted increases in soybean processing, pig producers may have increased availability of a cost-effective protein source in soybean meal (SBM). This expanded availability of SBM may result in feeding protein above the ostensible requirements, which would likely intensify the thermic effect of digestion, potentially increasing the susceptibility of the pig to heat stress (HS). Heat stress has damaging effects on feed intake and growth performance, costing the swine industry >$900 million annually. Therefore, the study objectives were to evaluate the effects of dietary crude protein diets (in the form of SBM) during HS on growth performance in growing pigs. Growing pigs (n = 40; initial BW = 55 ± 5.6 kg) were allocated into six treatments: 1) thermoneutral (TN) ad libitum control diet (TN-Ctl; n = 6), 2) TN pair-fed (PF) control diet (PF-Ctl; n = 6), 3) HS ad libitum control diet (HS-Ctl; n = 8), 4) TN ad libitum high SBM diet (TN-SBM; n = 6), 5) TN PF high SBM diet (PF-SBM; n = 6), and 6) HS ad libitum high SBM diet (HS-SBM; n = 8). The control diet included 15% crude protein (CP) while the high SBM diet included 23% CP with excess amino acids. The study consisted of two periods: Period 1 (P1; 7 d) in which all pigs were housed in TN environments (26.7 ± 1.4°C) with ad libitum access to respective diets. Period 2 (P2; 21 d), HS groups were exposed to cyclical HS with daytime temperatures reaching 35°C and evening temperatures decreased to 29.4°C. During P2, PF groups were fed to respective HS-Ctl or HS-SBM equivalents in TN conditions. Pigs exposed to HS had an overall increase in rectal temperature and respiration rate (0.91°C and 45 bpm, respectively; P≤ 0.01) and HS-SBM pigs had increased evening rectal temperature (± 0.13°C; P≤ 0.01), relative to HS-Ctrl. Overall, HS decreased ADFI (19%; P≤ 0.01), ADG (26%; P≤ 0.01) and increased F:G (10%; P≤ 0.01) irrespective of dietary CP levels. Loin muscle area (P= 0.19) and backfat (P= 0.98) were not different between the TN and HS pigs regardless of diet. Circulating blood urea nitrogen levels did not differ between HS and TN pigs (P= 0.68), but an increase was observed in pigs fed the SBM diet relative to the control diet (P≤ 0.01). In summary, these results demonstrate that HS decreases growth performance, but the negative effects are not augmented by feeding a high SBM diet.

Within the last decade, increased sow mortality resulting from pelvic organ prolapse (POP) has become a growing concern in the swine industry. Despite being widely acknowledged as a prevailing sow welfare and production issue, mitigation strategies are lacking. Previous studies have demonstrated changes in the vaginal microbiome are associated with increased risk for POP during late gestation. Therefore, the vaginal microbiome represents a potential target for prevention strategies. The objective of the current study was to evaluate effects of vaginal infusion using ampicillin on POP incidence. We hypothesized that altering the vaginal microbiome through the use of antibiotics would reduce POP risk during late gestation. Ampicillin was infused into the vagina at two timepoints during late gestation. The first dose (10 mL at 200 mg/mL) was administered approximately three weeks prior to farrowing followed by a second, equivalent dose at approximately three days pre-farrowing. Sows were randomly assigned to treated (TRT; n = 824) and non-treated (CON; n = 739) groups based on gestation pen. Eighty-seven percent of sows in the TRT group received both infusions of ampicillin. At gestation week 15, sows (n = 1076) were evaluated for prolapse risk using a 3-point perineal scoring system. Briefly, a perineal score (PS) of 1 (PS1) presumes little to no risk of prolapse, a PS of 2 (PS2) presumes moderate risk of POP, and a PS of 3 (PS3) presumes high risk of prolapse. From the 1,076 sows assigned a PS, 46.5%, 49.7% and 3.8% of sows were scored PS1, PS2, or PS3, respectively. Ampicillin treatment did not affect PS (P= 0.20) during late gestation, with 45.6%, 51.6% and 2.8% of CON sows and 47.2%, 48.1% and 4.7% of TRT sows scoring a PS1, PS2, or PS3, respectively. Additionally, treatment did not affect POP incidence (P= 0.74), with 4.5% of CON sows and 4.7% of TRT sows subsequently experiencing POP. When evaluating litter characteristics, ampicillin treatment did not affect number of total born, liveborn, or stillborn piglets (P≥ 0.54). However, an effect of PS was observed on total born and stillborn piglets (P≤ 0.01), and a tendency to effect number of liveborn piglets (P= 0.06). Sows assigned a PS3 during late gestation had fewer piglets born alive, presumably due to the increased number of stillborn piglets. Additionally, PS3 sows had 1 more total piglet on average within their litters compared with PS1 assigned sows (P= 0.01). In conclusion, vaginal infusion of ampicillin had no effect on PS, POP incidence or litter characteristics, but PS did have an effect on the number of piglets born alive. This project was supported by the National Pork Board and the Foundation for Food and Agriculture Research.

The swine industry is comprised of highly productive and healthy sows capable of weaning large litters for multiple parities. This prolificacy has resulted in greater metabolic demands during lactation due to increased capacity and demand for milk production. Modern sows also have increased genetic merit for leanness which has altered the amount of energy reserves available for mobilization to support the growing demands of lactation. Together, these factors may render modern sows more vulnerable to metabolic disorders such as postpartum dysgalactia syndrome (PDS) or mastitis-metritis-agalactia (MMA). Described as a metabolic and hormonal disturbance, a hallmark of PDS is a reduction (dysgalactia) or cessation (agalactia) in milk production after farrowing. Insufficient milk production by the sow leads to increased piglet mortality, causing substantial economic losses, reducing sow welfare, and resulting in premature removal of sows from the herd. Our prior reports have shown differences in circulating analytes and inflammatory markers between healthy sows and sows affected with PDS following parturition. However, very few differences were observed before clinical signs were evident, rendering these analytes ineffective in early detection of PDS. Therefore, the objective of the current study was to utilize gas-chromatography mass-spectrometry (GC-MS) to further characterize the biological conditions and metabolic pathways contributing to PDS in sows. Through this, we aimed to identify small molecules in circulation with the potential for use as a biomarker to aid in early detection of PDS. To accomplish this, a study was conducted on a commercial sow farm with a history of poor lactation performance. Sows (n = 36) with clinical signs of PDS were matched by parity and day of lactation with healthy control (CON) sows (n = 36) that remained unaffected. Blood samples collected at farrowing (timepoint 1) and at onset of clinical PDS (timepoint 2) were subjected to GC-MS. As expected, piglets from PDS sows had decreased (P< 0.01) average daily gain and greater mortality than piglets from control sows. Following GC-MS analysis, 16 and 41 molecules were identified as significantly different between CON and PDS sows at timepoint 1 and timepoint 2, respectively (P< 0.10). A difference in 2-hydroxybutyric acid, an early marker for insulin resistance and impaired glucose regulation, was observed at timepoint 1. Additional molecules identified as significantly different at timepoint 1 include D-pinitol, D-glucose, inositol (3,6)-bisphosphate, and others. These differentially abundant molecules at timepoint 1 represent potential biomarkers for early detection of PDS.

Postpartum dysgalactia syndrome (PDS) is a condition affecting periparturient sows, characterized by a reduction in milk and colostrum synthesis shortly after farrowing. Insufficient milk production results in substantial economic losses due to increased piglet morbidity/mortality and premature sow culling. Since PDS develops within a few days following farrowing, the study objectives were to determine if periparturient immune cell profiles and circulating biomarkers differ in sows affected by PDS. We hypothesized differences in immune cells, circulating analytes, and inflammatory markers would exist at farrowing in sows that subsequently developed PDS compared to healthy herd-mates. Thirty-six sows with PDS symptoms were matched by parity and day of lactation with 36 healthy control (CON) sows. Diagnosis of PDS (timepoint 2) occurred on average 9.25 ± 2.67 d after farrowing. Blood samples and litter weights were collected at farrowing (timepoint 1) and at the onset of clinical PDS (timepoint 2). Piglets from PDS sows had lower average daily gain and higher mortality than piglets from CON (P< 0.01). Aspartate aminotransferase was increased (20%; P≤ 0.06) in PDS sows compared to CON at both timepoints. Additionally, blood urea nitrogen was increased in PDS sows at timepoint 1 and timepoint 2 (13%; P= 0.08 and 16%; P= 0.01, respectively). At timepoint 2, total protein, globulin, magnesium, and cholesterol were increased (P≤ 0.03) while γ-glutamyl transferase and albumin were decreased (P≤ 0.02) in PDS sows. Lipopolysaccharide-binding protein, an inflammatory biomarker, was increased (48%; P= 0.07) at timepoint 2 in PDS compared to CON sows. Collectively, these data indicate PDS sows have altered metabolism and appear immune activated compared to healthy herd-mates, and further investigation is needed to determine if PDS can be predicted at farrowing.Postpartum dysgalactia syndrome (PDS) is a multifactorial disorder characterized by reduced milk production and resulting in substantial economic losses to the swine industry due to negative effects on piglet growth and mortality. Evaluating hematological factors before and after PDS diagnosis could lead to timely and more targeted interventions to minimize piglet mortality and improve sow longevity.Postpartum dysgalactia syndrome (PDS) is a multifactorial disorder affecting periparturient sows characterized by a pronounced reduction (dysgalactia) in milk secretion. Insufficient milk production limits piglet growth, leading to increased piglet mortality and often removal of affected sows from the herd, ultimately compromising sow longevity and negatively impacting the profitability of swine operations. The objective of this study was to determine if differences in circulating immune cells, analytes, and inflammatory markers exist at farrowing in sows that subsequently develop PDS compared to healthy herd-mates. Thirty-six sows with PDS were matched by parity and day of lactation with 36 healthy control (CON) sows. Blood samples were collected at farrowing (timepoint 1) and at the onset of clinical PDS (timepoint 2). Differences in markers of tissue catabolism (blood urea nitrogen, β-hydroxybutyrate, aspartate aminotransferase, alanine aminotransferase) and inflammation (lipopolysaccharide-binding protein, haptoglobin, albumin) were observed in PDS sows compared to control, suggesting PDS sows have altered metabolism and are potentially immune activated compared to healthy herd-mates.

Agalactia is characterized by reduced milk production after farrowing, resulting in economic losses due to increased piglet mortality. Although a variety of management factors have been associated with the etiology of agalactia, a specific causative mechanism has not been identified. Since clinical signs of agalactia develop in the days following farrowing, the objective of the current study was to determine if periparturient immune cell profiles and circulating biomarkers are predictive of future agalactia. Blood samples and litter weights were collected from sows (n = 374) within 24-36 hours after farrowing (timepoint 1) and sows were subsequently monitored for symptoms of agalactia and gaunt piglets. When a sow was designated as agalactic (n = 36) blood samples and litter weights were collected again (timepoint 2) and also from a parity matched healthy control sow (n = 46) of the same day of lactation. Agalactia diagnosis occurred on average 9.25 ± 2.67 d after farrowing. Average daily gain (ADG) of piglets from agalactic sows was 55% less (P< 0.01) than ADG of piglets from controls. Additionally, piglet mortality was substantially greater (P< 0.01) in litters from agalactic sows compared with controls. Circulating immune cells and metabolites were determined. Cholesterol, blood urea nitrogen, and globulin were increased 22.3, 17.8, and 34.1%, respectively, in agalactic compared with control sows at timepoint 2 (P≤ 0.01). Aspartate aminotransferase tended to increase in agalactic sows compared with control at timepoint 1 (P= 0.08). No differences in immune cell profiles were observed between agalactic and control sows at either timepoint (P≥ 0.14). Collectively, these data suggest metabolic changes are occurring in sows experiencing agalactia compared with healthy herd mates, but that very few of the metrics analyzed at timepoint 1 predicted future agalactia. This project was supported by Zoetis; TI-07023.

Seasonal infertility (SI) caused by heat stress (HS) impacts the US swine industry by reducing litter size, farrowing rates, and production efficiency. Identifying the biological underpinnings of SI is a foundational step towards developing mitigation strategies to reduce the nearly $1 billion annual revenue losses to the swine industry. The study objective was to investigate the direct and indirect effects of HS via HS conditioned serum infusion in swine. We hypothesized gilts housed in thermoneutral (TN) conditions receiving gradual infusions of serum obtained from HS gilts would experience altered endocrine and metabolic function compared to gilts receiving serum from TN gilts. Prepubertal gilts (n = 18) were assigned to donor or recipient groups and donors were allocated to TN or HS environments. Blood was collected from HS donors and TN donors exposed to 24-hours of HS or TN conditions, respectively. Serum was infused into recipients housed in TN conditions via indwelling jugular catheters. Over a 24-hour period approximately 20% of the estimated recipient gilt serum volume from donors (pooled by treatment) was infused into recipients. After infusions were completed, gilts were euthanized and tissues collected. Increased rectal temperatures were observed in HS recipients compared to TN recipients (P ≤ 0.05). Protein extracts from liver and ovary underwent proteomic analysis via liquid-chromatography with tandem mass-spectrometry (LC-MS/MS) to assess protein abundance. In the liver and ovary, we identified 135 and 264 proteins, respectively, that were differentially abundant between TN and HS recipients (P < 0.10). Gene Ontology enrichment analysis identified alterations to pathways involved in hormone regulation, immune response, and apoptosis. Collectively, these data demonstrate gilts receiving HS serum experienced altered endocrine and metabolic function compared to gilts receiving TN serum. This project was supported in part by the Iowa Pork Producers Association. USDA is an equal opportunity provider and employer.

Sow mortality has increased during the last decade with a large portion due to pelvic organ prolapse (POP) manifesting during late gestation and early lactation. Approximately 21% of sow mortality is attributed to POP, creating a significant economic and animal welfare concern. The study objective was to identify differences in sow fecal microbiota associated with POP risk and to determine if fecal and vaginal microbial communities are correlated. Using an established perineal scoring (PS) system, 2,864 sows were assigned PS1 (low), PS2 (moderate), or PS3 (high) based on phenotypic observations and presumed POP risk during gestation week 15. Of those sows scored, 1.0%, 2.7%, and 23.4% of PS1, PS2, and PS3 assigned sows, respectively, subsequently experienced POP. At the time of scoring, fecal swabs were collected from sows (n = 213) and DNA was extracted for 16S rRNA gene Illumina MiSeq sequencing, and analyzed using mothur, phyloseq and SAS. Additionally, co-occurrence networks were constructed between fecal and vaginal microbial communities using CoNet (V1.1.1), to identify correlations in taxa abundance. Differences in fecal community composition (PERMANOVA; P< 0.05), structure (alpha diversity measurements; P< 0.05), and 13 individual operational taxonomic units (OTU; Q < 0.05) were detected between PS1 and PS3 sows. The abundance of several taxa were correlated across sample collection sites, suggesting the fecal and vaginal microbial communities may influence one another. Collectively, fewer differences exist in fecal microbiota in sows differing risk for POP than previously observed in vaginal microbiota, suggesting the vaginal microbial communities may be a better indicator of POP risk. Understanding correlations between the fecal and vaginal microbial communities may provide strategies or targets for combatting POP. This project was supported by the National Pork Board and the Foundation for Food and Agriculture Research.

Postpartum metritis, or the inflammation of the uterus after parturition, is often a direct result of bacterial infection and considered to contribute to agalactia / dysgalactia in multiple species. Diagnosing metritis has included evaluation of vaginal and cervical fluid (CF) discharge for signs of infection (i.e., purulent discharge, strong odor, and discoloration). Metritis in sows results in economic losses for the swine industry due to increased numbers of sows requiring repeat inseminations to establish pregnancy, longer weaning to estrus intervals, association with increased abortions, and is also linked to agalactia. This study aimed to compare the microbial communities of the CF, the vaginal cavity, and feces from sows shortly after parturition, to identify similarities and differences in relative microorganism abundance between these body sites. Fecal and vaginal swabs were collected from 82 sows within 24-36 hours post-parturition. Additionally, CF was collected from each sow and classified based on color and consistency. Extraction of DNA was performed from all 246 samples and used for 16S rRNA gene Illumina MiSeq sequencing. Sequence analysis was conducted using MOTHUR (V1.43.0). No changes in CF microbial community composition or structure were determined related to CF color but differences (P< 0.05) were detected relative to CF consistency. Taxa were compared across body sites to identify correlated phylotypes using CoNet (V1.1.1). The abundances of several phylotypes harboring metritis-relevant pathogens were correlated with common commensal microorganisms across body sites (including Fusobacterium, Streptococcus, Escherichia, and Staphylococcus) suggesting interactions between these body sites exist. This work provides initial insights into postpartum sow CF microbial communities, and the interconnectedness with the vaginal and fecal microbiota. This project was supported by Zoetis (TI-07021).

Porcine pregnancy establishment and maintenance are dependent on the formation of functional corpora lutea (CL). Manganese (Mn) is critical for CL function as it is a cofactor for Mn superoxide dismutase and enzymes involved in cholesterol synthesis. Previously, we have shown that luteal Mn content increased and luteal progesterone (P4) concentration decreased in the CL of gilts fed diets supplemented with an Mn–amino acid complex (Availa-Mn; Zinpro Corporation) compared with controls fed Mn sulfate. Importantly, serum P4increased from 0 (estrus onset) to 12 d post estrus (dpe), as expected, but P4abundance in circulation was not affected by dietary Mn source (P= 0.15). We hypothesized that a more bioavailable Mn source (which results in increased luteal Mn content) would alter the luteal proteome and abundance of mRNA associated with steroid biogenesis during the mid-luteal phase of the estrous cycle. Postpubertal gilts (n= 32) were assigned to one of the four gestation diets. The control diet (CON) contained 20 ppm of supplemental Mn in the form of Mn sulfate. Three additional diets included 20 (TRT1), 40 (TRT2), or 60 (TRT3) ppm of supplemental Mn in the form of a Mn–amino acid complex instead of Mn sulfate. Dietary treatment began at estrus synchronization (approximately 20 d before estrus) and continued through 12 dpe when gilts were euthanized and tissues were collected. Protein and total RNA extracts from the CL were used for proteomic analysis via label-free liquid chromatography with tandem mass spectrometry to assess global protein abundance and quantitative real-time polymerase chain reaction (qRT-PCR) to assess specific mRNA abundance, respectively. Compared with CON, 188, 382, and 401 proteins were differentially abundant (P< 0.10) in TRT1, TRT2, and TRT3, respectively. Gene Ontology enrichment software revealed that proteins involved in P4signaling and cholesterol synthesis were downregulated in CL of gilts fed Mn–amino acid complex compared with controls. Quantitative RT-PCR showed that relative transcript abundance of genes encoding steroidogenic enzymes (CYP11A1and StAR) in CL tissue was decreased in gilts from TRT2 compared with CON (P= 0.02), but TRT1 and TRT3 were not affected (P≥ 0.30). Collectively, these data support our hypothesis that a more bioavailable dietary Mn source may influence luteal function by altering the abundance of protein and mRNA involved in steroidogenesis.

Sow mortality, as the result of pelvic organ prolapse (POP), has been increasing in the last decade in the U.S. swine industry. The objective of this study was to identify potential biological markers associated with risk of POP in sows. We hypothesized that sows differing in perineal score (PS) from PS1–PS3 (PS1—a presumed low POP risk; PS2—a presumed moderate POP risk; and PS3—a presumed high POP risk) would differ in circulatory biomarkers of inflammation and hormonal profiles. On gestation week 15, 2,864 individual sows were assigned a PS, and subsequently, 1.0%, 2.7%, and 23.4% of PS1, PS2, or PS3 sows, respectively, experienced POP. During PS assignment at days 107–116 of gestation, blood samples were collected from sows on two farms of similar genetics, feed sources, and health status. Whole blood was subjected to complete blood count (CBC) analysis (n= 212) and steroid hormones were measured in serum from a subset (n= 110) of animals assigned PS3 parity matched to PS1. Lipopolysaccharide-binding protein (LBP), tumor necrosis factor-alpha (TNF-α), haptoglobin, C-reactive protein (CRP), and creatine kinase (CK) levels were also evaluated. Complete blood count analysis revealed decreased (P≤ 0.05) mean platelet volume (3.9%), lymphocytes (6.5%), and monocytes (7.5%) in PS3 compared to PS1 sows. Increased (P≤ 0.02) abundance of androstenedione (13.4%), androsterone (18.2%), estrone (24.8%), and 17β-estradiol (26.2%) was observed in PS3 compared to PS1 sows. Additionally, a 25.8% increase (P= 0.04) in LBP in PS3 compared to PS1 sows was observed. Many dynamic physiological changes occur in sows during late gestation as they approach farrowing. The data presented herein demonstrate that distinct differences in concentrations of circulating biomarkers exist between late gestation sows at high or low risk for POP and may serve as a useful tool for understanding the etiology of POP and evaluation of mitigation strategies.

Functional corpora lutea (CL) are required for pregnancy establishment and gestational maintenance in swine, and CL function is susceptible to environmental influences. Manganese (Mn) could be critical in regulating CL function since it is a component of the antioxidant enzyme Mn superoxide dismutase (MnSOD) as well as enzymes involved in cholesterol and steroid hormone synthesis. We hypothesized that a more bioavailable dietary Mn source would increase Mn content in the CL thereby influencing luteal function during the mid-luteal phase of the estrous cycle. Postpubertal gilts (n= 32) were assigned to one of four gestation diets. The control diet (CON) met or exceeded National Research Council (2012) requirements and was formulated to contain 20 parts per million (ppm) of added Mn in the form of Mn sulfate. Three additional diets included 20 (treatment [TRT]1), 40 (TRT2), or 60 (TRT3) ppm of added Mn from a Mn–amino acid complex (Availa-Mn; Zinpro Corporation) instead of Mn sulfate. Dietary treatment began at estrus synchronization onset and continued through 12 days post estrus (dpe) of the ensuing estrous cycle. Blood samples were collected at estrus onset, which was assigned as 0 dpe, as well as 4, 8, and 12 dpe. Gilts were euthanized and tissues were collected at 12 dpe. Serum progesterone (P4) increased (P< 0.01) from 0 to 12 dpe but was unaffected by dietary treatment (P= 0.15) and there was no effect of the interaction between day and treatment (P= 0.85). Luteal Mn content increased (P≤ 0.05) by 19%, 21%, and 24% in gilts fed TRT1, TRT2, and TRT3, respectively, compared to CON. Luteal P4concentrations decreased (P= 0.03) 25%, 26%, and 32% in gilts fed TRT1, TRT2, and TRT3, respectively, compared to CON. Relative to CON gilts, CL calcium content decreased (P= 0.02) by 36%, 24%, and 34% for TRT1, TRT2, and TRT3 gilts, respectively. Collectively, these data support the hypothesis that feeding a more bioavailable Mn source increases Mn accumulation in CL tissue. If and how this influences CL function may be related to altered luteal P4concentrations.