bluuebunny/crossref_metadata_2025 huggingface dataset:
184 Increased feeding level in peak lactation is an effective tool to control body weight loss in hyper prolific sows
Authors: Bruun Thomas S , Højgaard Camilla K , Strathe Anja V
Published: July 2019

Research has shown that feed restrictions in late lactation can increase BW loss and affect subsequent reproduction. Therefore, this study was designed to determine how increasing maximum daily feed allowance (MDFA) in late lactation and litter size (LS) affected body weight (BW) and back fat (BF) loss, and subsequent reproduction in sows nursing above 12 piglets. A total of 619 DanBred sows (parity 1 to 5) were randomly assigned to 1 of 6 treatments combining 2 levels of LS (12 or 14 piglets) and 3 levels of MDFA (6.17 kg; 7.20 kg; 8.23 kg; DM basis). Maximum feed allowance was achieved at d 15 and kept constant to weaning at d 24. The diet was formulated to contain 11.2 MJ NE/kg DM and to comply with all AA according to Danish recommendations. Sows were fed 3 times a day. Standardization of litters were done within 48 h after farrowing. Sows were weighed and BF measured in P2 at litter standardization and at weaning to calculate BW and BF loss during lactation. In total, 543 of 619 sows with 0 or 1 dead piglet during lactation were included in the data, and linear mixed models were used for data analysis. No interaction between LS and MDFA was found (P > 0.05). Loss of BW (16.2 kg and 21.0 kg; P < 0.0001) and BF (2.42 mm and 2.94 mm; P < 0.0001) increased when LS increased from 12 to 14 piglets, respectively. Increasing MDFA reduced BW loss from 24.5 kg to 18.3 kg to 13.0 kg (P < 0.0001), whereas BF loss decreased from 3.0 mm to 2.8 mm to 2.3 mm (P < 0.0001). Subsequent farrowing rate and total born piglets in the next litter were unaffected by MDFA (P = 0.149 and P = 0.527, respectively). In conclusion, BW and BF loss of lactating sows can be controlled efficiently by increasing MDFA in peak lactation.
189 Comparative transcriptomic analysis between Total RNA and mRNA isolated from feces of neonatal dairy calves
Authors: Osorio Johan S , Rosa Fernanda
Published: July 2019

The fecal RNA method can be used to evaluate biological adaptations of the gastrointestinal tract of dairy calves through gene expression analysis. The process of RNA isolation from fecal samples presents several challenges, including the potential enrichment of prokaryotic (bacterial), RNA which can dilute the targeted eukaryotic RNA and consequently affect the sensitivity of the fecal RNA method to low expressed genes. Therefore, our objective in this study was to determine the differential eukaryotic RNA enrichment in total RNA vs mRNA from feces of healthy neonatal dairy calves. To test this, a comparative transcriptomic profiling of genes specific for epithelial cells, including cytokeratin 8 (KRT8) and aquaporin (AQP3), as well as inflammatory-related genes (TLR4 and IL1B) was performed in fecal samples collected from 6 pre-weaned Holstein calves. The total RNA was isolated from 200 mg of feces, using a Trizol based method along with the RNeasy Plus Mini Kit (Qiagen). Then, 45 μg of fecal total RNA was used to isolate mRNA through magnetic selection using Dynabeads® Oligo (dT)25 (Invitrogen). The standard curve was composite from all samples including cDNA from total RNA and mRNA. The internal control genes used in this experiment were B2M, ACTB, GAPDH, RPS9, and PPIA. Normalized gene expression data were log-transformed prior to statistical analysis using the Proc Mixed of SAS (SAS 9.4). The expression of KRT8 was greater (P = 0.03) in fecal mRNA than in fecal total RNA. A trend (P = 0.09) was observed for greater expression of TLR4 in fecal total RNA than in fecal mRNA. The expression of AQP3 and IL1B was not different. These preliminary data further confirms that fecal RNA method has potential to be used as a tool to evaluate gastrointestinal tract health in dairy calves, but further adjustments are needed to improve accuracy and robustness.
192 Effects of continuously infusing glucose or casein at the terminal ileum on biomarkers of metabolism and intestinal morphology in growing pigs
Authors: Mayorga Edith J , Horst Erin A , Al-Qaisi Mohmmad , McCarthy Carrie S , Goetz Brady M , Abeyta Megan A , Lei Samantha , Acosta Jesus A , Patience John F , Baumgard Lance H
Published: July 2019

Objectives were to determine the effects of continuously infusing glucose (GLU) or casein (CAS) at the terminal ileum on circulating metabolism and intestinal architecture in pigs. Crossbred gilts (81 ± 1 kg BW) fitted with ileocecal cannulas and jugular catheters were enrolled in 2 experimental periods (P). Period 1 (4 d) served for the collection of baseline measurements. At the beginning of P2 (4 d), pigs were assigned to 1 of 3 infusion treatments: 1) control (CTL; water; n = 7), 2) GLU (500 g/d; n = 6), and 3) CAS (300 g/d; n = 6). Water, GLU, and CAS solutions were continuously infused (125 mL/h) through the ileocecal cannula for the entirety of P2. Pigs were sacrificed following P2 and segments of jejunum, ileum, and colon were collected. Data were analyzed using the MIXED procedure of SAS. During P2, circulating glucose and non-esterified fatty acids were similar among treatments (P > 0.10). A tendency for a treatment × time interaction was observed for insulin as it decreased over time in CTL pigs, while it remained almost unchanged in GLU and CAS treatments during P2 (P = 0.07). Blood urea nitrogen (BUN) decreased in GLU relative to CTL pigs during P2 (21%; P = 0.01), whereas it gradually increased (76%; P < 0.01) from 6 to 96 h post-infusion in CAS pigs when compared to their CTL counterparts. No differences on fecal pH were observed across treatments (P = 0.62). Ileum villus height tended to increase in CAS relative to CTL pigs (P = 0.08). Similarly, ileum villus height:crypt depth was increased in CAS compared to CTL pigs (P = 0.02). Goblet cell area was similar across treatments but tended to decrease in the jejunum in GLU when compared to their CTL counterparts (P = 0.09). In conclusion, continuously infusing GLU or CAS into the terminal ileum differently altered BUN patterns, but surprisingly had little effects on intestinal morphology.
191 Early weaning in pigs induces long-term alterations in intestinal nutrient transporter function and expression partially via beta adrenergic enteric neural receptors
Authors: Li Yihang , Matos Karina , Rajput Mrigendra , Moeser Adam James
Published: July 2019

Early weaning (EW) has negative impacts on performance and health that persist from wean-to-finish. The mechanisms linking EW and lifetime performance reductions are poorly understood. The objective of this study was to investigate whether EW influences the long-term development of intestinal epithelial nutrient transporter function and expression and the potential mechanisms. Yorkshire gilts were split-weaned from their sows at 15 d (EW) or 28 d of age (Late Weaning; LW) and transferred to an on-site nursery room. All pigs received the same diets in a standard phase feeding program and were euthanized at 75 d of age. Mid-jejunum and distal ileum were mounted on Ussing chambers to evaluate Na+-dependent glucose and amino acid (AA) transporter function, measured as nutrient-induced changes in short circuit current (Isc). EW gilts exhibited reduced capacity for electrogenic transport of glucose (by ~30%; P < 0.05) and glutamate, glutamine, and alanine by (~ 30–35%; P < 0.05), compared with LW pigs. In contrast, jejunal and ileal lysine transporter function was upregulated (by 110% and 25%, respectively; P < 0.05) in EW pigs. Epithelial expression for glucose transporter (SGLT1) was reduced (P < 0.05) while glucose/fructose transporter (GLUT2), fructose transporter (GLUT5) and lysine transporters (B0AT1, CAT1, and ATB0, +) were enhanced in the EW jejunum. No differences observed in villus morphology between EW and LW pigs. Pretreatment of ileal mucosa on Ussing chambers with the Na+ channel blocker (Tetrodotoxin) or the β-adrenergic receptor blocker (Propranolol) augmented glucose, lysine and alanine transporter function in EW but not LW pigs. Together, these data show that EW in gilts induces lasting and divergent alterations in intestinal nutrient transporter function and expression which is mediated in part by the enteric nervous system and β-adrenergic receptor pathways. These new findings may explain why EW pigs exhibit lasting deleterious impacts on performance. Further mechanism-based investigations could reveal new targets for optimizing performance in EW pigs throughout the production lifespan.
193 Characterisation of poor gastrointestinal tract development in gilt progeny
Authors: Wijesiriwardana Danni A , Craig Jessica , Ringuet Mitchell , Fothergill Linda , O’Halloran Kirrily , Turpin Diana , Munoz Lynette , Collins Cherie , Furness John B , Pluske John , Cottrell Jeremy , Dunshea Frank R
Published: July 2019

Progeny of primiparous sows (gilts) have poor production performance compared to those of multiparous sows. This has been attributed to underlying biological events that occur early in life. We specifically focused on the development of the gastrointestinal tract (GIT) and its function in sow vs gilt progeny (SP vs GP) reared under commercial conditions. Piglet tissues were harvested at birth, at 24 h, and pre- and post-weaning (28 v 29 d) and used to quantify GIT integrity. All data were analysed using Genstat V18 for the effects of parity (sow vs gilt) in birth (0 vs 24 h) and weaning (pre- vs post) cohorts. GIT integrity was quantified from freshly excised tissue in Ussing chambers for transepithelial electrical resistance (TER) and macromolecule permeability (FD4; labelled 4kD dextran). Permeability was measured in stomach, colon, jejunum and ileum. Over the 24-h neonatal period, TER was significantly reduced in the stomach and colon (P = 0.048 and 0.003 respectively) with GP having lower stomach TER than SP (P = 0.015). TER increased in the jejunum and ileum over the 24-h neonatal period (P = 0.004 and 0.002 respectively). An interactive effect of parity and time on ileum FD4 was observed (P = 0.043) where FD4 in SP ileum decreased over the 24-h neonatal period and FD4 in GP ileum increased over the 24-h period (P = 0.043). Jejunum FD4 was significantly higher in GP than SP over the 24-h neonatal period (P = 0.048). An interactive effect of parity and time was observed in the colon over the weaning period where TER increased in SP but decreased in GP (P = 0.005). Stomach TER decreased over the weaning period in both GP and SP (P = 0.013). Jejunum and ileum TER decreased over the weaning period (P = 0.003 and 0.057 respectively). Ileum FD4 was higher in GP than SP over the weaning period (P = 0.037). These findings reflect a reduction in GIT development in GP compared with SP, and gut leakiness may be an underlying reason for poorer production performance and increased morbidity of GP.
194 Performance and febrile response of nursery pigs to a porcine reproductive and respiratory syndrome virus challenge
Authors: Jasper Jessica , Helm Emma T , Todd Blaire , Gabler Nicholas K
Published: July 2019

Porcine reproductive and respiratory syndrome (PRRS) virus is an economically significant pathogen that antagonizes production in all stages of the swine industry. In nursery pigs, it increases the risk of mortality and reduces growth performance parameters. Thus, the objective of this study was to further understand how PRRS virus infection and its associated viremia and serology levels related to febrile response and performance in nursery pigs. Over two replicates, 37 three-week post-weaned PRRS naïve gilts (11.2 ± 2.56 kg BW) were randomly assigned to one of two treatments: Control (CON, n = 16) or PRRS virus-inoculated (PRRS+, n = 21). All pigs were housed individually in a BSL2 facility for the 21 d test period. PRRS serology, BW, ADG, ADFI, and G:F were determined at 0, 7, 14 and 21 days post inoculation (dpi). Core body temperatures were collected daily using a biosensor microchip. Data was analyzed using mixed procedure of SAS with dpi as a repeated effect and CON or PRRS+ as a treatment effect. Treatment, dpi and their interactions were assessed. As expected, viremia and antibody titers in PRRS+ pigs were significantly different compared to CON pigs, which remained negative (P < 0.001). The lowest PRRS Ct was observed at dpi 7, while antibody titers were highest between dpi 14 to 21 (P < 0.001). Compared with the CON, PRRS+ reduced BW gains by 17, 33 and 42% at dpi 7, 14 and 21 respectively (P < 0.001). The PRRS challenge also reduced ADFI by 30, 67 and 68% at dpi 7, 14 and 21 respectively, compared to CON (P < 0.001). The febrile response in the PRRS+ pigs peaked between dpi 7 and 14 then returned to CON baseline level by dpi 21 (P < 0.001). Overall, PRRS virus challenge induced a sustained febrile response that contributes to the attenuated performance of nursery pigs.
195 Depriving piglets of maternal feces changes piglet physiology and performance before and after weaning
Authors: Aviles Edgar O , Rakhshandeh Anoosh , McGlone John J
Published: July 2019

Coprophagy has been described in piglets, but its effects on piglet physiology, behavior, and performance have not been fully assessed. Therefore, this study was conducted to evaluate how deprivation of maternal feces influenced these measures before and after weaning. Eight litters were randomly assigned to one of two treatments following a CRD design: Control and treatment (TRT). Piglets in the control group had access to maternal feces while piglets in TRT litters were deprived of maternal feces for the first 7 d of age. Measures of piglet behavior were observed for 24 h on d 7 of age. Blood samples were collected from two piglets from each litter (i.e. male and female) at 0, 7, and 21 d of age for hematological analyses. Litters were weaned at 25 ±2 d of age and post-weaning growth performance was assessed until 100 d post weaning. During the first 3 d post-partum, sow fecal output was low or absent. After 3 d post-partum, sows defecated 220.7 ± 43.86 g/d (DM basis). No treatment effects were observed on measures of behavior, hematocrit or hemoglobin at 0, 7, and 21 d of age (P > 0.05). Relative to the control group, TRT piglets had 25% lower WBC numbers (PP ≤ 0.05). At 100-d post-weaning, control pigs were 8.33 ± 1.9 kg heavier than TRT pigs (P < 0.05). Collectively, these results show that when piglets had access to maternal feces during the first 7 d of age, while not changing nursing or other behaviors, they had better pre- and post-weaning performance than piglets deprived of maternal feces. Further studies are needed to determine the mechanisms (nutritional, microbial, or pheromonal) through which maternal feces changes physiology and improves the growth of piglets.
196 Direct comparison of human microbiota-associated (HMA) gnotobiotic piglet and mouse models
Authors: Aluthge Nirosh D , Tom Wesley A , Bartenslager Alison C , Burkey Thomas E , Heath Kelly D , Kreikemeier-Bower Craig , Kittana Hatem , Ramer-Tait Amanda E , Fernando Samodha C
Published: July 2019

The objective of this study was to compare the establishment of human fecal bacterial communities in porcine and murine animal models. Many gut microbiota studies use human microbiota-associated (HMA) rodents as translational animal models; however, it has been questioned as to how successfully a human microbiota can be established in rodents considering the many differences that exist between rodents and humans. The domestic pig (Sus scrofa domesticus) has many anatomical, physiological, and immunological similarities to humans and has been widely used as a model for humans in biomedical and nutritional studies. Thus, the porcine model may be an alternative to rodent models in gut microbiota research. The current study was designed to evaluate the establishment of the same human donor microbiota in the rodent and pig models. Both germ-free piglets and mice (C3H/HeN) were transplanted with fecal microbiota from four human donors: Infant (0–5 m), child (1–12 yrs), adult (18–64 yrs), and elderly (65+ yrs). To monitor the establishment of the transplanted microbiota, weekly fecal samples were collected for 5 wks. All fecal samples were subjected to 16S rRNA gene-based amplicon sequencing using the Illumina MiSeqTM platform to characterize bacterial community composition. Unweighted unifrac distances were compared between the bacterial communities of the human donor and the corresponding HMA porcine and murine fecal samples. Statistical significance was tested using the Mann-Whitney U test (P = 0.05). This analysis suggested that more taxa are colonized in the mice compared to the piglets receiving the same infant donor microbiota, while for the child, adult, and elderly donors, the piglet model established the human donor microbiota better than the mice receiving the same donor samples. This suggests that in the latter stages of human development, more species of the human fecal inoculum colonizes the pig gut compared to the mouse gut.
200 Improving efficiency of embryo transfer (ET) programs by optimizing fertility and management of recipients
Authors: Wiltbank Milo , Garcia-Guerra Alvaro , Sala Rodrigo V , Fosada Meliton , Carrenho-Sala Luciana , Moreno Juan F
Published: July 2019

Multiple experiments were performed to optimize efficiency and fertility in recipients of fresh in vitro produced (IVP) embryos. In experiment 1, heifers (n = 520) were synchronized and received an embryo on d 6–8 after estrus or 6–8 d after GnRH in a fixed time ET (FTET) program using modified 5-d CIDR-Synch protocol (d-8: CIDR inserted; d-3: CIDR removed and PGF2α treatment; d-2: second PGF2α; d0: GnRH to induce ovulation). Pregnancy per ET (P/ET) at d 32 and d 60 were similar but pregnancy per treated potential recipient (efficiency of recipient utilization) was greater for FTET than estrus (+49.7%). Subsequent experiments sought to optimize FTET protocol by analyzing whether CIDRs could be used multiple times (up to 4 uses similar P/ET) and whether multiple PGF2α treatments were needed at end of program (no difference when no GnRH given at start of protocol). Thus, a simple, inexpensive FTET program has similar fertility as ET after estrus but is more efficient at recipient utilization. A large retrospective analysis (n = 12,569 ET) was performed using FTET program. Embryo stage and quality were major embryo factors impacting P/ET. Transfer of d 7 fresh embryo to d 7 or d 8 recipient was better than d 6 (+24.4%). Two experiments (GnRH or CIDR treatment) evaluated increasing circulating P4. In GnRH experiment, heifers (n = 1,562) on d5 received GnRH (200 μg) or Control (untreated). On D12, P4 was greater (P < 0.001) in GnRH-treated (7.2 ± 0.1ng/ml) vs Controls (6.0 ± 0.1ng/ml). There was greater P/ET at D33 and D60 of pregnancy for Stage 7 than 6 embryos. Treatment with GnRH did not alter P/ET but decreased pregnancy loss between D33 and D60 in heifers receiving Stage 7 embryos (11.6 vs 27.6% in recipients with accessory CL on d 33). In CIDR experiment, treatment with 2 CIDRs (from d 13; one new CIDR each 7 d) elevated circulating P4 and tended to decrease pregnancy loss (d 27 to 62; 25.9 vs 11.9%) and increase P/ET (40.4 vs 53.6% on d 62). Thus, elevating P4 decreased pregnancy loss during FTET program using fresh IVP embryos.
204 Genomics of age at puberty in gilts
Authors: Ciobanu Daniel
Published: July 2019

Our previous research demonstrated that age at puberty is characterized by moderate heritability and is an early pre-breeding indicator of sow fertility. Early selection of gilts, based on genomic prediction of age at puberty and fertility in general, is considered a potential approach to reduce sow culling. Phenotypes, genotypes and tissues from UNL resource population (n > 1,700) were used in initial genome-wide association to identify regions of the genome associated with age at puberty. The proportion of phenotypic variation for age at puberty explained by the Porcine SNP60 BeadArray was 27.3%, with top genomic regions responsible for relatively small effects. The top 1-Mb windows (1%) explained 6.7% of the genetic variation with one window located on SSC2 (12–12.9 Mb) displaying pleiotropic features, affecting both age at puberty and litter size. These top genomic regions were oversaturated with new genetic variants discovered by deep genomic and RNA (arcuate nucleus) sequencing, which were integrated in SowPro90, a custom Affymetrix SNP array. Using a subset of sows representing extremes of the distribution for age at puberty (n = 283) and genotyped with the SowPro90 led to identification of a SNP in the proximal promoter of the UBE2L6 (SSC2, 13.3Mb; F = 13.39; P = 0.0003), a gene known to modulate function of ISG15, a marker for pregnancy. This novel SNP, which exceeded the effect of the original top SNP in the region (DIAS0004771; F = 6.98), explained 6.8% of the proportion of phenotypic variance. Identification of functional polymorphisms that influence age at puberty could lead to improvements in the accuracy of genomic prediction while reducing sow replacement rates. This project was supported by AFRI Competitive Grant no. 2013-68004-20370 from the USDA-NIFA.
208 Molecular mechanisms through which heat stress compromises reproduction in pigs
Authors: Ross Jason W , Hale Benjamin J , Seibert Jacob T , Romoser Matthew R , Adur Malavika K , Keating Aileen F , Baumgard Lance H
Published: July 2019

Seasonal variations in environmental temperatures impose added stress on domestic species bred for economically important production traits. These heat-mediated stressors vary on a seasonal, daily, or spatial scale, and negatively impact behavior and reduce feed intake and growth rate, which inevitably leads to reduced herd productivity. The seasonal infertility observed in domestic swine is primarily characterized by depressed reproductive performance manifesting as delayed puberty onset, reduced farrowing rates, and extended weaning-to-estrus intervals. Understanding the effects of heat stress at the organismal, cellular, and molecular level is a prerequisite to identifying mitigation strategies that could reduce the economic burden of compromised reproduction. Additionally, hyperthermia experienced in utero influences industry-relevant postnatal phenotypes. Understanding tissue-specific molecular mechanisms through which heat stress confers suppressed reproductive ability is essential to the development of mitigation focused hypothesis driven solutions. This work was supported by the National Pork Board and the Iowa Pork Producers Association.
209 Effects of heat stress on the intestinal tract of poultry
Authors: Rostagnos Marcos
Published: July 2019

Stress is a biological adaptive response to restore homeostasis, and occurs in every animal production system, due to the multitude of stressors present in every farm. Heat stress is one of the most common environmental challenges to poultry worldwide. It has been demonstrated that heat stress negatively impacts the welfare and productivity of broilers and laying hens. However, our knowledge of basic mechanisms associated to the reported effects, as well as related to poultry behavior and welfare under heat stress conditions is in fact scarce. The adaptive response of poultry to a heat stress situation is complex and intricate in nature, and it includes effects on the intestinal tract. Intervention strategies to deal with heat stress conditions (e.g., management practices, feed additives, diet formulation, and others) have been the focus of most published studies. Nevertheless, effectiveness of most of the interventions has been variable or inconsistent. This review focuses on the scientific evidence available on the effects of the heat stress response on different facets of the intestinal tract of poultry, including its integrity, physiology, immunology and microbiology.
218 Effect of GnRH injection at -72 h in MGA-PG estrus synchronization protocol
Authors: Erickson McKay , Funston Rick N
Published: July 2019

Beef heifers (n = 1524) from two operations in central Nebraska were randomly assigned to one of two treatments [0 or 5 μg GnRH at prostaglandin F2α (PGF) administration 72 hrs before insemination]. Both locations utilized MGA-PG fixed-time AI (TAI) estrus synchronization protocol. The first location (L1, n = 1076, 382 ± 3 kg) processed heifers 72 hours prior to insemination and every third heifer was assigned to receive an injection of GnRH (5 ug) (TRT) and an injection of PGF. The remaining heifers received PGF and 0 μg GnRH. At insemination all heifers received 100 ug GnRH. Heifers were then observed for estrus behavior from 10–21 days post TAI and re-inseminated if estrus was detected. Heifers pregnant from the second breeding were added to final pregnancy rate. The second location (L2) utilized estrus detection patches and performed only TAI (n = 448, 363 ± 7 kg) following MGA-PG synchronization protocol outlined above without the estrus observation period. Treatment did not significantly (P > 0.20) improve TAI pregnancy rates [L1 TAI 56.3% (TRT) vs 57.3%; L1 AI Total 78.3% (TRT) vs 73.9%; L2 TAI 58.5% (TRT) vs 52.5%] among the two herds. The administration of 5 μg GnRH at PGF tended to increase (P = 0.12, 74% vs 63%) pregnancy rates for those inseminated during the follow up heat detection period at L1. The treatment did not (P > 0.20) improve pregnancy for the time-AI heifers. In addition, TAI pregnancy rates were similar (P > 0.20) at L2. There were greater (P < 0.20) effect of pen on pregnancy rate.
215 Influence of BVDV exposure on AI conception and breeding season pregnancy success in beef herds
Authors: Epperson Kaitlin M , Rich Jerica J J , Zoca Saulo Menegatti , Perkins Stephanie D , Northrop Emmalee J , Daly Russell F , Walker Julie A , Rhoades Jim R , Perry George A
Published: July 2019

Bovine Viral Diarrhea Virus (BVDV) causes reproductive and economic losses in cattle. The objective of this study was to evaluate the influence of BVDV exposure on reproductive success (AI and breeding season conceptions). Well vaccinated cows (n = 367) and heifers (n = 540) from 9 different herds were synchronized using the 7-d CO Synch + CIDR protocol and were fixed-time AI (FTAI). On d 28 following insemination, blood samples were collected, and pregnancy status was determined by transrectal ultrasonography and the IDEXX Rapid Visual Pregnancy Test. Non-pregnant animals were resynchronized and FTAI a second time. In six herds bulls were comingled with females beginning 10-15 d after the second AI. Final pregnancy status was determined 33–80 d following the first pregnancy diagnosis. Blood samples were tested for the presence of BVDV antigen using the IDEXX BVDV PI X2 Kit. Positive samples were indicative of animals with an active infection. Herds were determined as having BVDV exposure by the presence of at least one animal having a positive test for active antigen (n = 4 exposed herds, n = 5 non-exposed herds). Statistical analyses were performed using the GLIMMIX procedure of SAS. Herds that had BVDV exposure during the breeding season had significantly decreased (P < 0.01) first service AI conception rates compared to herds that had no exposure (34 ± 2.3% vs. 54 ± 2.3%). Additionally, breeding season pregnancy rates were decreased (P < 0.01) in herds that had BVDV exposure compared to non-exposed herds (69 ± 3.4% vs. 80 ± 3.6%). There was no significant effect of BVDV exposure on embryonic loss (P = 0.42) or percentage of animals which lost a pregnancy and rebred by the end of the breeding season (P = 0.63). In conclusion, BVDV exposure in well vaccinated herds still had a negative effect on both first service AI conception rate and overall breeding season pregnancy success.
217 Influence of daily temperature fluctuations on estrus activity determined by an electronic estrus detection system and conception to artificial insemination in cross-bred beef heifers
Authors: Cushman Robert A , Chase Chadwick C , Rich Jerica J J , Northrop Emmalee J , Thallman R Mark , Snelling Warren M , Kuehn Larry A , Brown-Brandl Tami M , Perry George A
Published: July 2019

Behavioral estrus occurs in response to estradiol, and the intensity of activity registered in some electronic estrus monitoring systems is greater in dairy cows that conceive to artificial insemination compared to cows that do not conceive. Ambient temperature may influence estrus activity and follicular development. Therefore, we hypothesized that differences in temperature would associate with peak activity and conception to artificial insemination in cross-bred beef heifers. Heifers (n = 346) in south central Nebraska were observed twice daily for 21 d for behavioral estrus and artificially inseminated between June 4 and June 25, 2018. Onset of estrus and peak activity were extracted from the electronic system. Ambient temperature was merged with onset of estrus, and data were analyzed using the MIXED procedure of SAS with pregnancy status to artificial insemination as a class effect. There was no difference in peak activity between heifers that conceived to artificial insemination and heifers that did not conceive to artificial insemination (P = 0.45). The ambient temperature at onset of estrus was greater for heifers that did not conceive to artificial insemination than for heifers that conceived to artificial insemination (P < 0.05). Time of onset significantly influenced peak activity (P < 0.01), with the greatest peak activity occurring in the early morning hours and in the early evening hours. Daily temperatures increased until 1600 h and decreased thereafter (P < 0.01). Differences in peak activity do not associate with conception to artificial insemination in beef heifers as in dairy cows, but temperature at onset of estrus influenced conception to artificial insemination. Based on increased peak activity in the evening when temperatures were still greater than the early morning hours, the perceived trajectory of temperature may influence behavioral estrus more than the actual temperature. USDA is an equal opportunity provider and employer.
226 Impact of corn silage level on finishing cattle nutrient digestion, ph characteristics, and feeding behavior
Authors: Wilson Hannah C , Jolly-Breithaupt Melissa L , Watson Andrea K , MacDonald James C , Erickson Galen E
Published: July 2019

When used as a roughage source in a finishing diet, corn silage can have different effects on digestion compared to hay because of the presence of additional corn grain. The objective of this study was to determine the effects of corn silage inclusion level on cattle digestion and feeding behavior. In a digestion study, 3 ruminally cannulated steers (430 kg ± 0.20 kg) were utilized in a generalized randomized block design with 8 periods. Treatments consisted of 3 levels of corn silage included at 0, 7.5 and 15% of the diet DM and a control treatment with 15% alfalfa. Results showed DMD, OMD, NDF digestibility, and ADF digestibility were greatest for cattle fed CS0 followed by CS7.5, CS15, and Alf (P < 0.01). Average ruminal pH was least for CS0, CS7.5 was intermediate, followed by Alf and CS15 with the greatest pH (P < 0.01). Total VFA production was greatest in cattle fed CS0 followed by CS7.5 and Alf with CS15 having the least. Acetate to propionate ratio was least for cattle fed CS0, intermediate for CS7.5 and CS15 and greatest for Alf. Cattle ate the same number of meals which were similar in size as a % of total DMI (P ≥ 0.60). However, cattle fed Alf and CS0 spent more time eating compared to cattle fed CS7.5 and CS15 (P = 10). The rate of intake (kg/hr) was greatest for CS15 (9.55) and decrease linearly for CS7.5 (9.44), Alf (8.12) and least for CS0 (7.68; P = 0.04). These data suggest that cattle, typically at high risk for reduced performance, are susceptible to negative effects of high grain diets, like acidosis, when fed no or low inclusion of roughage. Feeding silage at 15% was similar to feeding alfalfa at 7.5%.
223 Effects of high protein DDGS in SFC or DRC-based diets on nutrient digestibility and ruminal fermentation characteristics
Authors: Ovinge Lauren , Norman Mitch , Wheeler Kaylee , Erickson Galen E
Published: July 2019

The effect of high protein dried distillers grains plus solubles in steam flaked corn (SFC) or dry rolled corn (DRC)-based diets on rumen fermentation and nutrient digestion was evaluated. Six ruminally and duodenally cannulated heifers were utilized in a 6×6 Latin Square experiment using a 2×3 factorial treatment design. One factor was SFC or DRC-based diets, and the other factor was a control with no DGS (CON), regularly produced DDGS (DDGS), or High Protein DDGS (HiPro) included at 30% in the diet (DM basis). Data were analyzed using the MIXED procedure of SAS, with individual steer within period as the experimental unit. There was an interaction of apparent total tract starch digestibility (P 0.01), as including either DDGS or HiPro reduced starch digestibility in DRC-based diets and tended (P = 0.06) to reduce starch digestibility in SFC-based diets. Digestibility of starch was greater (P < 0.01) for SFC versus DRC-based diets across distillers treatments. Dry matter and OM apparent total tract digestibility was lowest (P < 0.01) for HiPro and DDGS was intermediate. There was no difference in molar acetate proportions (P > 0.43) between treatments. Dry rolled corn tended (P = 0.08) to have greater propionate proportion than SFC (44 vs 38%; respectively). Ammonia concentration was greater (P < 0.01) for DRC-based diets, and greatest for CON (P < 0.01) over DDGS and HiPro treatments. Average ruminal pH was unaffected by treatment (P > 0.16). Digestible energy (Mcal/kg) tended (P = 0.08) to be greater for CON over HiPro and DDGS. The use of HiPro did not affect apparent total tract nutrient digestibility as compared to DDGS in SFC or DRC-based diets. The use of either distillers product did result in a reduction in energy intake and digestibility, without affecting ruminal metabolic parameters.
222 Effect of corn stalk inclusion rate on performance and rumination behavior in beef steers
Authors: Jennings Jenny S , Lockard Catherine L , Lawrence Ty E
Published: July 2019

Coarse roughage, such as corn stalks, in feedlot diets aids in the formation of a fibrous mat within the rumen. The fibrous mat supports rumen health, buffers pH, and reduces acidosis risk in cattle consuming high-concentrate diets. Excess roughage can increase physical fill, thus lowering the animal’s ability to consume enough energy for efficient growth. The objective of this experiment was to quantify feedlot growth performance, rumination, ruminal pH and carcass quality and yield outcomes of cattle consuming a finishing diet with increasing levels of roughage. Fifty-one steers (initial BW = 295 + 11 kg) were randomly allocated to 1 of 3 dietary treatments; 5% (5CS; n = 18), 10% (10CS; n = 17), or 15% (15CS; n = 16) corn stalks (DM basis) in a steam-flaked-corn based finishing diet. Steers were fitted with a sensory collar that recorded rumination (min/d) and one-half of the steers (n = 27) received a rumen bolus that continuously monitored pH. The experiment was conducted using a randomized complete block design. Data were analyzed using a mixed model; treatment was a fixed effect and block was a random effect. As CS inclusion increased, we observed increased DM intake (P = 0.01; 7.7, 8.2, and 8.5 kg/d, respectively), decreased gain efficiency (P < 0.01; 0.18, 0.16, and 0.14 kg/kg DM, respectively), and a tendency for decreased ADG (P = 0.09; 1.34, 1.33, and 1.22 kg/d, respectively). Ruminal pH was highest (P < 0.01) for 15CS (6.28) and similar for 5CS and 10CS (6.10). Steers spent more time ruminating (P < 0.01) when consuming the 10CS diet (361 min/d) and least with 5CS diet (279 min/d). Increasing CS to 15% decreased rib fat thickness (P = 0.01), decreased calculated YG (P = 0.02), and decreased marbling score (P < 0.01) compared with the 5CS and 10CS treatments. Feeding excess corn stalks (≥ 15%) may prevent adequate energy intake, thus diminishing feedlot growth performance and carcass merit.
229 Characterization of the rumen bacterial communities of bison heifers maintained on a pasture-based diet
Authors: Fresno Rueda Anlly M , Griffin Jason , Kruse Carter , St-Pierre Benoit
Published: July 2019

The North American bison has evolved to thrive on a diverse range of habitats and climate. As a ruminant, it is dependent on the metabolic activities of symbiotic microorganisms to digest the plant fibers that make up the majority of its diet. To gain further insight into the bison rumen environment, which has remained largely unexplored, the primary objective of this study was to determine the diversity and composition of ruminal bacteria in bison fed a pasture-based diet. Ruminal content from 19 heifers maintained on pasture at the Standing Butte Ranch (North Stanley, South Dakota, USA) was collected by stomach tubing. Following extraction of microbial genomic DNA, PCR was performed to amplify the V1–V3 region of the 16S rRNA gene, then amplicons were sequenced using an Illumina MiSeq(2×300) platform. Next-generation sequence data was then analyzed using a combination of custom Perl scripts, publicly available software (Mothur v. 1.40) and online tools (RDP classifier and NCBI Blast). Bacteroidetes and Firmicutes were found to be the dominant phyla in the rumen environments analyzed, together representing 85.3% to 96.6% of sequence reads in individual samples. In contrast, the ratio of Bacteroidetes to Firmicutes showed a much broader range (0.57 to 3.90), suggesting that the rumen bacterial communities of the sampled animals exhibited a wide array of distinct composition patterns. However, Pearson correlation analysis did not support an association between the Shannon alpha diversity index and the abundance of either Bacteroidetes or Firmicutes (P > 0.05). Interestingly, Pearson correlation analysis supported a positive association between Bacteroidetes and Fibrobacteres (P < 0.05), as well as between Firmicutes and Planctomycetes (P < 0.05). Together, these results suggest that at least two rumen enterotypes, Bacteroidetes-Fibrobacteres and Firmicutes-Planctomycetes, can be distinguished in the rumen of North American bison heifers maintained on a pasture-based diet.
332 Young Scholar Presentation: regulation of immune signaling by extracellular vesicles
Authors: Ylioja Caroline M , Mamedova Laman K , Bradford Barry J
Published: July 2019

Exosomes and other extracellular vesicles traffic a variety of protein and nucleic acid cargo throughout the body. Immune cells especially utilize these vesicles for communication, and they are being studied in clinical settings for their potential to act as disease markers, but also to serve as drug delivery systems. In animal science, a large part of the research around exosomes has centered around their presence in milk, as well as their bioavailability and potential impact for the neonate and for humans; milk-derived exosomes are enriched with immune-related proteins and microRNA that may relate to maternal health, mammary function, or neonate development. We sequenced miRNA isolated from colostrum of dairy cows predicted to feature either moderate or high degree of immune suppression, but found minimal differences (2 differentially expressed miRNA of 343 miRNA analyzed) between the two groups. Immune suppression exhibited during early lactation may also be related to altered exosome-mediated communication between immune cells. We studied the ability of bovine exosomes to alter immune responses of primary bovine monocyte-derived macrophages and found that exosomes alone or in combination with LPS were able to stimulate cytokine production to a greater extent than LPS alone. The ability of exosomes to transport cytokine, bioactive lipid, and regulatory RNA cargo suggests potential involvement in transition cow health. Altered exosome content and function have been associated with uterine infection, mastitis, and metabolic dysfunction; future studies with exosome signaling may help clarify the complexities of transition cow immune function and point to strategies to support immunity.
336 Effects of supplemental SoyPass in forage-based diets containing distillers grains on performance of growing steers
Authors: Spore Tyler J , Carlson Zachary E , Erickson Galen E , Klopfenstein Terry , Watson Andrea K
Published: July 2019

One hundred twenty individually fed steers (initial BW 283 kg) were utilized in an 84-d growing trial to evaluate effects of increased metabolizable lysine from non-enzymatically browned soybean meal (SoyPass) in grass hay based diets containing wet distillers grains plus solubles (WDGS). Treatments were arranged as a 2 × 3 factorial design with two levels of WDGS (20% or 35% of DM) and three levels of supplemental SoyPass replacing 0%, 30%, or 60% of WDGS. The statistical model included animal as the experimental unit and level of WDGS and SoyPass substitution were included as fixed effects. Covariate regression was used to test for linear and quadratic interactions between WDGS and SoyPass substitution. No interactions were detected for ADG between SoyPass supplementation and level of WDGS in the diet (P = 0.76). Additionally, SoyPass inclusion had no effect on ADG (P = 0.49). However, ADG was increased for steers consuming the 35% WDGS diet compared to steers offered the 20% WDGS diet (1.13 vs. 0.86 kg/d, respectively; P < 0.01). A SoyPass × WDGS interaction was detected for DMI (P = 0.01). As SoyPass replaced WDGS in the 35% diet, DMI increased linearly from 8.10 to 8.93 kg/d (P = 0.01). In the 20% WDGS diet, DMI decreased as SoyPass replaced 60% of the WDGS compared to 30% (7.68 vs. 8.36, P = 0.02). Therefore, G:F decreased linearly (P = 0.01) as SoyPass replaced WDGS in the 35% treatment and increased quadratically (P = 0.02) for the 20% WDGS treatment. Furthermore, BUN increased linearly as SoyPass replaced WDGS in the 20% diet (P = 0.01) but was not affected by SoyPass substitution in the 35% diet. Overall, results indicate forage-based growing diets formulated with low-levels of WDGS (< 20%) may be deficient in metabolizable lysine, which could be supplied with SoyPass.
335 Metabolizable protein requirement of lightweight beef calves
Authors: Redden Miles D , Shike Daniel W , McCann Joshua C
Published: July 2019

The objective was to assess the metabolizable protein (MP) requirements of lightweight beef steers. The 2016 Beef Cattle Nutrient Requirements Model (BCNRM) prediction of MP requirements in lightweight beef steers (less than 250 kg) is limited by available performance data in beef calves. Fall born Angus × Simmental crossbred steers (n = 172; BW = 153 kg) were weaned at 70 d of age (± 26 d), backgrounded 73 d, implanted with Component TE-IS, blocked by BW as light (96–163 kg) or heavy (163–215 kg), and assigned to one of four treatments for 56 d. Treatment diets provided MP at: 0.59 (MP1), 0.69 (MP2), 0.85 (MP3), and 0.91 kg per d (MP4) based on observed DMI. Energy was similar across all treatments at 2.14 Mcal/kg ME. Shrunk body weights were collected on d 0 and 56 to estimate performance. Dry matter intake was affected (P < 0.01) by treatment and increased (linear; P < 0.01) with greater provision of MP. As a percent of shrunk body weight, DMI averaged 2.8% and tended (linear; P = 0.07) to increase with MP. Based on observed DMI, ADG for MP1, MP2, MP3, and MP4 was predicted using the BCNRM at 1.15, 1.55, 1.99, and 1.98 kg, respectively. Observed ADG increased quadratically (P = 0.01) with MP1, MP2, MP3, and MP4 gaining 1.86, 2.13, 2.3, and 2.3 kg, respectively. Final BW increased (quadratic; P = 0.02) with greater MP as MP1, MP2, MP3, and MP4 were 258, 273, 282, and 284 kg, respectively. Gain:feed increased quadratically (P = 0.04) with observed values for MP1, MP2, MP3, and MP4 being 0.323, 0.357, 0.359, and 0.360, respectively. Steer ADG response exceeded BCNRM predictions by 29%. Data suggest MP requirements of lightweight beef steers (BW = 213 kg) are 0.85 kg per d to achieve 2.3 kg ADG when fed a 2.14 Mcal/kg ME diet.
341 Evaluation of the safety of an algal biomass as an ingredient in finishing cattle diets
Authors: Norman Mitch , Carlson Zachary E , Hilscher Fred H , Erickson Galen E , Brodersen Bruce , Loy John , Wilson Jonathan , Rabe Christian , Watson Andrea K
Published: July 2019

Algae production is increasing to supply the growing demand for Omega-3 fatty acids for aquaculture, human food and pet food; co-products from the algae industry could be a suitable feed ingredient for cattle feeding. A safety study was conducted to evaluate feeding algal biomass to cattle. Crossbreed cattle (20 steers and 20 heifers, 255 kg initial BW, SD=14) were individually fed 4 inclusions of condensed algal residue solubles (CARS; 0, 2.5, 5, 7.5 % of diet DM) displacing dry rolled corn in a finishing diet (62.5 to 70% corn and 15% distillers grains) for a minimum of 97 d. At harvest, organs were weighed and sampled. Blood was collected every 30 d. Performance data were analyzed as a RCBD with treatment, gender, and treatment by gender interactions as fixed effects, BW block as a random effect and individual animal as the experimental unit. Orthogonal contrasts were used to test for linear, quadratic and cubic responses due to CARS inclusion. Increasing CARS in the diet quadratically increased DMI and ADG (P ≤ 0.01). A linear increase was observed for G:F, NEm,and NEg as CARS increased in the diet (P < 0.01). All organ weights measured were within expected ranges for cattle, with 6 out of 27 having differences in weight due to treatment (P ≤ 0.05). Histopathology analysis of organs revealed no differences due to treatment (P ≥ 0.24). Out of 21 blood chemistry measures, 8 were affected by treatment (P ≤ 0.02). Nearly all blood chemistry parameters were within expected ranges for cattle. No adverse effects of feeding CARS were observed in hematology, blood chemistry, or histopathology analyses. The feedstuff CARS demonstrated to be a safe and efficacious feed ingredient for cattle diets and maximized HCW, ADG, and DMI when fed at 2.5 or 5% of the diet.
338 Effect of eicosapentaenoic acid and docosahexaenoic acid supplementation on placenta and fetal liver mRNA, and fetal liver and brain fatty acids profile on early gestation in sheep
Authors: Roque Jose Alejandro , Oviedo Mario Francisco , Lee Hector Aaron , Relling Alejandro E
Published: July 2019

Polyunsaturated fatty acids supplementation in late gestation change offspring metabolism; however, their effect is not well known on early gestation in ewes. The objectives of this study were to determine the effect of dietary supplementation with eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) in pregnant ewes on the concentration of EPA and DHA on fetal liver (FL) and fetal central nervous system (FCNS), and to evaluate the effect of the supplementation with EPA+ DHA on mRNA expression of genes associated with transport and metabolism of fatty acids (FA) in FL and placenta (caruncles and cotyledons). Twelve ewes (4 pens, three per pen) were blocked by pregnancy day. The ewes were assigned during the first 45 d of gestation to diet with an addition of 1.5% (dry matter bases) monounsaturated FA (MUFA) or EPA+DHA. A C-section was conducted at d 45 of gestation to collect FL, FCNS, caruncle and cotyledon. Data were analyzed using a mixed procedure (SAS). For the placenta mRNA concentration, a 2x2 factorial was used considering caruncle and cotyledon as the second main factor. Isomers of C18:1 (t6,8 and t12) increase (P < 0.05) in FL and FCNS with MUFA supplementation, fatty acids C20:3 (n-6), C20:3 (n-3), C22:1, C22:5 and C22:6 increase (P < 0.05) in FL and FCNS with EPA+DHA supplementation. In FL there was a tendency to increase for mRNA expression of FATP-1 (P = 0.10) with EPA+DHA supplementation, while mRNA concentration for LPL was greater (P = 0.02) for MUFA supplementation. In placenta DNMT3b and FFAR-4 showed a significant FA x tissue interaction (P < 0.05). These results suggest that FA supplementation during early gestation alters the FA profile in FL and FCNS and changed mRNA concentration of genes involved in the transport of FA and cell metabolism.