Mortality In Pigs Research Articles

CD1d facilitates African swine fever virus entry into the host cells via clathrin-mediated endocytosis

ABSTRACT African swine fever (ASF) is a highly contagious and acute hemorrhagic viral disease with high morbidity and mortality in domestic pigs and wild boars. The disease has become a global threat to the pig production industry and has caused enormous economic losses in many countries in recent years. However, the molecular mechanism underlying ASF virus (ASFV) entry of the host cells is not fully understood, which restricts the development of vaccines and antiviral-drugs of ASFV. In this study, we found that the host protein CD1d acts as a host factor, which mediates ASFV entry into the host cells. As the main capsid protein on the surface of ASFV virions, p72 can mediate viral entry. Using IP-MS assay, CD1d was identified as a binding partner of p72 on surface of ASFV virions. Knockdown of CD1d expression and blocking the cells with anti-pCD1d antibody, or incubating ASFV virions with soluble CD1d protein could significantly inhibit ASFV infection. CD1d is located on the membrane surface of primary porcine alveolar macrophages (PAMs) and mediates the virus entry via binding to p72. CD1d knockout or CD1d knockdown assay showed that CD1d could facilitate ASFV virions internalization via clathrin-mediated endocytosis (CME). Furthermore, CD1d interacts with EPS15 to mediate ASFV entry via clathrin-mediated endocytosis. Overall, our findings revealed that CD1d is a novel host-entry factor involved in ASFV internalization via the EPS15-clathrin endocytosis axis and a potential target for antiviral intervention.

Structure of the pork value chain in Northern Uganda: implications for Taenia solium control interventions.

This study characterizes the pork value chain in Agago, Kitgum, Lamwo, and Pader districts of Northern Uganda and analyzes its implications on the transmission and control of Taenia solium infections. Data were collected through focus group discussions (FGDs) with farmers and pig and pork traders, key informant interviews (KIIs) with local government officials and consumers, and district-level multi-stakeholder mini workshops organized in the study area. The value chain actors identified include input and services providers, pig farmers, live pig traders, pork traders, and consumers. Most of the pig production, marketing and consumption was found to occur through informal channels. Pig production in this area is dominated by smallholder extensive systems, with most producers keeping less than 10 pigs. The production segment of the pig value chain is characterized by low use of inputs and services such as veterinary extension, drugs and improved feeds. Pigs scavenge for food under free-range systems and are at risk of parasitic infections such as the zoonotic helminth Taenia solium. This risk is exacerbated by the inherent contextual aspects of the study sites including low latrine coverage, open defecation, and high poverty. In addition, some respondents viewed pigs as "sanitation policemen" where they leave them to roam around and eat dirt including feaces thereby cleaning the environment. T. solium was recognized as an important pig health constraint in this value chain alongside African swine fever (ASF). Unlike ASF that was associated with the pig mortalities, the cysts were associated with rejection of pigs by traders at purchase, condemnation of pig carcasses by meat inspectors and rejection of raw pork by consumers at points of sale. Poor organization of the value chain and lack veterinary extension and meat inspection services results in some pigs infected with T. solium entering the food chain, exposing consumers to infection with the parasite. To reduce the pig production losses and public health impact from T. solium infections, there is need for control and prevention interventions targeting specific nodes of the value chain where the risk of transmission is highest.

Complete genome analysis of African swine fever virus genotypes II, IX and XV from domestic pigs in Tanzania

African swine fever (ASF) caused by ASF virus (ASFV) is an infectious transboundary animal disease notifiable to the World Organization for Animal Health causing high mortality in domestic pigs and wild boars threatening the global domestic pig industry. To date, twenty-four ASFV genotypes have been described and currently genotypes II, IX, X, XV and XVI are known to be circulating in Tanzania. Despite the endemic status of ASF in Tanzania, only one complete genome of ASFV from the country has been described. This study describes the first complete genome sequence of ASFV genotype XV. In addition, the first Tanzanian complete genome of ASFV genotype IX and three ASFV strains belonging to genotype II collected during ASF outbreaks in domestic pigs in Tanzania were determined in this study using Illumina sequencing and comparative genomics analysis. The generated ASFV complete genome sequences ranged from 171,004 to 184,521 base pairs in length with an average GC content of 38.53% and encoded 152 to 187 open reading frames. The results of this study provide insights into the genomic structure of ASFV and can be used to monitor changes within the ASFV genome and improve our understanding of ASF transmission dynamics.

Effects of Core Antigen Bacterin with an Immunostimulant on Piglet Health and Performance Outcomes When Challenged with Enteric and Respiratory Pathogens.

A total of 90 pigs, approximately one day of age, were used in a 42-day study to evaluate whether Endovac-Porci, a core antigen vaccine with an immunostimulant, provides piglets with broad-spectrum protection against the enteric and respiratory effects of Gram-negative bacteria. This study was a single-site, randomized, prospective, blinded, comparative placebo-controlled design. Individual pigs were randomly allocated to 1 of 2 treatments in a randomized design. An individual pig was considered the experimental unit for the farrowing phase (Study day 0 to 21), and the pen was considered the experimental unit for the nursery phase (Study day 21 to 42). Thus, there were 45 replications per treatment during the farrowing phase and 15 replications per treatment during the nursery phase. Treatments included a control product (saline; CP) and an investigational product (Endovac-Porci; IVP). On Study day 23, all pigs were challenged with enterotoxigenic Escherichia coli strain expressing K88 (F4) fimbriae and Pasteurella multocida. Individual pigs were weighed and feed consumption was measured to determine body weight gain, average daily gain, and feed-to-gain ratio. Clinical and fecal scores and overall health were recorded daily. Overall, administering the IVP to pigs led to an increase (p < 0.01) in body weight gain and average daily gain compared to pigs administered the CP. Pigs administered the IVP had reduced (p < 0.01) mortality compared to pigs administered the CP. There was a Study day × treatment interaction on clinical and fecal scores (p < 0.01). There was also a main effect of Study day where clinical and fecal scores increased (p < 0.01) as the Study day increased. Treatment also had an effect on clinical and fecal scores, where pigs administered the IVP had lower (p < 0.01) clinical and fecal scores compared to pigs administered the CP. In conclusion, administering pigs with the Endovac-Porci vaccination significantly improved the performance (i.e., body weight, body weight gain, and average daily gain) and health (i.e., clinical and fecal scores), while reducing the overall mortality in pigs challenged with E. coli K88 orally and Pasteurella multocida intranasally post-weaning. Results from this study suggest that Endovac-Porci could provide broad-spectrum protection against enteric and respiratory effects of Gram-negative bacteria in piglets.

The mass mortality of Asia's native pigs induced by African swine fever

AbstractAsia's wild pigs are ecosystem engineers and a key food for predators and people. The arrival of African swine fever (ASF) in 2018 induced near‐100% fatality in domestic pigs and decimated the Chinese pork industry in 2020 but outcomes for wild pigs have been delayed and unclear. Here we report on the mass mortality of native wild boar (Sus scrofa) in Peninsular Malaysia. ASF was confirmed at our long‐term study site in February 2022 and wild boar carcasses increased &gt;100‐fold in June 2022 compared to prior years. Camera trapping revealed an 87% decline in wild boar activity in 2022 compared to five prior surveys. Wild boars retired in old birthing nests and pairs of animals died next to each other in the open. Similar results are being anecdotally reported across the region with immense repercussions suspected on ecology and conservation. We urge a rapid research response to take advantage of this unique natural experiment.

Epizootics Associated in Ghoongroo Pig Mortality in an Organized Farm Under Hot and Humid Climatic Condition in West Bengal, India

Epizootics Associated in Ghoongroo Pig Mortality in an Organized Farm Under Hot and Humid Climatic Condition in West Bengal, India

Systematic Identification and Comparison of the Expressed Profiles of Exosomal MiRNAs in Pigs Infected with NADC30-like PRRSV Strain.

Exosomes are biological vesicles secreted and released by cells that act as mediators of intercellular communication and play a unique role in virus infection, antigen presentation, and suppression/promotion of body immunity. Porcine reproductive and respiratory syndrome virus (PRRSV) is one of the most damaging pathogens in the pig industry and can cause reproductive disorders in sows, respiratory diseases in pigs, reduced growth performance, and other diseases leading to pig mortality. In this study, we used the PRRSV NADC30-like CHsx1401 strain to artificially infect 42-day-old pigs and isolate serum exosomes. Based on high-throughput sequencing technology, 305 miRNAs were identified in serum exosomes before and after infection, among which 33 miRNAs were significantly differentially expressed between groups (13 relatively upregulated and 20 relatively downregulated). Sequence conservation analysis of the CHsx1401 genome identified 8 conserved regions, of which a total of 16 differentially expressed (DE) miRNAs were predicted to bind to the conserved region closest to the 3' UTR of the CHsx1401 genome, including 5 DE miRNAs capable of binding to the CHsx1401 3' UTR (ssc-miR-34c, ssc-miR-375, ssc-miR-378, ssc-miR-486, ssc-miR-6529). Further analysis revealed that the target genes of differentially expressed miRNAs were widely involved in exosomal function-related and innate immunity-related signaling pathways, and 18 DE miRNAs (ssc-miR-4331-3p, ssc-miR-744, ssc-miR-320, ssc-miR-10b, ssc-miR-124a, ssc-miR-128, etc.) associated with PRRSV infection and immunity were screened as potential functional molecules involved in the regulation of PRRSV virus infection by exosomes.

Antagonisms of ASFV towards Host Defense Mechanisms: Knowledge Gaps in Viral Immune Evasion and Pathogenesis.

African swine fever (ASF) causes high morbidity and mortality of both domestic pigs and wild boars and severely impacts the swine industry worldwide. ASF virus (ASFV), the etiologic agent of ASF epidemics, mainly infects myeloid cells in swine mononuclear phagocyte system (MPS), including blood-circulating monocytes, tissue-resident macrophages, and dendritic cells (DCs). Since their significant roles in bridging host innate and adaptive immunity, these cells provide ASFV with favorable targets to manipulate and block their antiviral activities, leading to immune escape and immunosuppression. To date, vaccines are still being regarded as the most promising measure to prevent and control ASF outbreaks. However, ASF vaccine development is delayed and limited by existing knowledge gaps in viral immune evasion, pathogenesis, etc. Recent studies have revealed that ASFV can employ diverse strategies to interrupt the host defense mechanisms via abundant self-encoded proteins. Thus, this review mainly focuses on the antagonisms of ASFV-encoded proteins towards IFN-I production, IFN-induced antiviral response, NLRP3 inflammasome activation, and GSDMD-mediated pyroptosis. Additionally, we also make a brief discussion concerning the potential challenges in future development of ASF vaccine.

Study of the mortality rate in pre-fattening pigs

The focus of this experimental work was the long-term analysis of the mortality of pigs in the pre-fattening category, as well as the determination of the most important etiological and predisposing factors of death. We carried out this research on farm in the east of Slovakia, in the Spiš region, over a period of three years. Based on our 36-month monitoring of pig mortality, we found that pre-fattening mortality was on a downward trend with mortality rates of 2.79%, 2.72% and 2.71% in consecutive years. There is also a certain seasonal impact on mortality in pre-fattening, because we found a higher incidence of deaths especially in the cold spring, autumn and winter months. Diseases such as respiratory and diarrheal diseases were among the most important etiological and predisposing factors of mortality in the observed farm.

Effects of gruel feeding and oral dextrose on the survivability of pigs after weaning.

Two experiments were conducted in a 14,400 head nursery using 3,087 (experiment 1) and 988 (experiment 2) pigs to determine the effect of gruel feeding (experiment 1) and supplemental oral dextrose (experiment 2) on nursery pig survivability after weaning. Upon arrival to the nursery, for experiment 1, the smallest 10% of pigs were selected and randomly placed in pens with 61 to 108 pigs per pen. Pens of small pigs were assigned to one of two treatments in a completely randomized design. Treatments consisted of gruel feeding two or four times per day for 14 d postplacement. At each gruel feeding, approximately 1.13 kg of solid feed was added to a round bowl (Rotecna S.A., Agramunt, Spain) located at the front of each pen and water added at a decreasing rate over time. In experiment 2, every other pig removed for welfare considerations (lameness, sick, or unthrifty) from the general population or pens of small pigs received a single 10 mL oral dose of a 50% dextrose solution (Vet One, MWI Animal Health, Boise, ID), as a source of glucose, before being placed in a removal pen. All removed pigs were tagged and weighed, body temperature recorded, and blood glucose concentration measured prior to and 30 min after entering removal pens. Overall, gruel feeding small pigs two or four times per day for 14 d postplacement did not influence (P > 0.10) mortality from weaning to the end of gruel feeding (3.78% vs. 4.25%, respectively). Likewise, dextrose administration did not influence (P > 0.10) pig mortality after removal to approximately 38 d postweaning (21.4% vs. 23.4% respectively), even though blood glucose concentration increased (P < 0.001) 30 min after removal for pigs administered dextrose. An interaction was observed for blood glucose concentration and body temperature (P < 0.001) where pigs with blood glucose concentrations less than 70 mg/dL had increased mortality as body temperature increased. In contrast, pigs with a blood glucose concentration of 70 mg/dL or greater had decreased mortality as body temperature increased. Pigs weighing less than 4.5 kg also had increased mortality (P < 0.001) compared with pigs weighing greater than or equal to 4.5 kg at removal. In summary, gruel feeding four times per day vs. two times per day or providing a dextrose supplement to pigs removed from the general population did not improve the survivability of pigs after weaning. Additionally, pigs removed with decreased body weight or with body temperature or blood glucose concentrations below or above the normal range had decreased survivability.

Efficacy of water application of a humic substance, butyric acid, vitamins C, D, and E and/or electrolytes on performance and mortality in health-challenged nursery pigs¹.

Health challenges continue to be rampant in nursery pigs which has led to increased industry-wide mortality trends. Therefore, the objective of these three studies was to evaluate a water supplement (HV; HydraVantage, Kent Nutrition Group, Muscatine, IA) which is a proprietary blend of a humic substance, butyric acid, and vitamins C, D, and E, as well as an electrolyte blend on nursery pig performance and mortality. Experiment 1 consisted of 196 crossbred weanling pigs (7 pigs per pen with 14 pens per treatment) which were randomly allotted by BW to two treatments consisting of control (water for 33 d) or HV at 15 g/L of stock solution and proportioned through a medicator (1:128) for 11 d followed by water for 22 d. There were no performance differences. However, mortality was reduced (P < 0.01) from 6.12% for the control to 0.00% for HV. In experiment 2, there were 488 weanling pigs (6 to 10 pigs/pen with 14 pens per treatment) which were randomly allotted by BW to four treatments in a 34-d trial. Treatment 1 was control (water), and treatments 2 and 4 were HV at 15 g/L of stock solution for 11 and 34 d, respectively. Treatment 3 utilized HV at 15 g/L stock solution during days 0 to 11 with 7.5 g HV/L stock solution utilized during days 11 to 21 followed by water. No performance differences were observed among the four treatments. Mortality was 10.89%, 4.82%, 5.54%, and 7.26% for treatments 1 to 4, respectively, with treatment 1 having a higher mortality (P < 0.05) compared to treatments 2 to 4. In experiment 3, a 2 × 2 factorial study was conducted (7 pigs per pen with 14 pens per treatment) in which the treatments were: 1) water; 2) HV at 15 g/L stock solution for 34 d; 3) electrolytes at 241 g/L stock solution for 34 d; and 4) HV at 15 g/L of stock solution and electrolytes at 226 g/L of stock for 34 d. Overall pen gain tended to be improved (P = 0.09) with supplemental HV. Moreover, mortality was reduced (P = 0.06) by 36% (16.86% mortality for treatments 1 and 3 vs. 10.73% mortality for treatments 2 and 4). Supplemental electrolytes had no effect on mortality. These data suggest that HV has a positive effect by reducing mortality in nursery pigs undergoing health challenges.

Evaluation of a Lactococcus lactis-based dried fermentation product administered through drinking water on nursery pig growth performance, fecal Escherichia coli virulence genes and pathotypes, antibiotic usage, and mortality.

A total of 34,749 pigs were used in two experiments to evaluate the effects of a postbiotic dried fermentation product (DFP) administered through drinking water on nursery pig growth performance, antibiotic injection frequency, morbidity, mortality, fecal consistency, and characterization of fecal Escherichia coli. The DFP is composed of bioactive molecules derived from Lactococcus lactis. In Exp. 1, 350 barrows (DNA Line 200 × 400; initial body weight [BW] 6.1 ± 0.01 kg) were used in a 42-d study with five pigs per pen and 35 pens per treatment. The DFP was supplied for 14 d at a target dosage of 24 mg/kg BW using a water medicator at a 1:128 dilution. On days 7 and 14, fecal samples were collected for dry matter (DM) and to determine, by a multiplex polymerase chain reaction (PCR) assay, prevalence of 11 virulence genes characteristic of E. coli pathotypes. There was no evidence (P > 0.10) for differences for growth, incidence of diarrhea, number of antibiotic injections, removals, or fecal DM. On both fecal collection days, E. coli virulence genes were present with day 7 samples positive for genes that encode for hemolysins (hlyA, exhA), intimin (eae), and enteroaggregative heat-stable enterotoxin (astA). Prevalence of enterotoxin genes (elt, estA, estB, astA) increased on day 14, but DFP had no effects on the prevalence of any of the virulence genes. A total of 32 out of 72 E. coli isolates were identified as enterotoxigenic pathotype and all except one were from day 14 fecal samples. Fourteen isolates were positive for F4 fimbria and one isolate was positive for F4 and F18 fimbriae. In Exp. 2, 34,399 nursery pigs (initially 5.6 kg) were used in 20 nursery barns with 10 barns per treatment (control or DFP). The target dosage of the DFP for the first 14 d was 35 mg/kg BW. Following the 14-d supplementation period, pigs continued to be monitored for approximately 31 d. There was no evidence (P > 0.05) for the DFP to influence the overall percentage of pigs that died or growth performance. From days 0 to 14, providing the DFP reduced (P < 0.05) the percentage of pigs that were euthanized. However, providing the DFP increased (P < 0.05) the overall percentage of pigs that were euthanized and total mortality. For the number of antibiotic injections (treatment interventions), providing the DFP reduced the number of injections for the common period (P < 0.001) and overall (P = 0.002). These results indicate that the DFP did not influence growth performance but providing the DFP in Exp. 2 led to increased total nursery pig mortality.

Nipah Virus Disease: Epidemiological, Clinical, Diagnostic and Legislative Aspects of This Unpredictable Emerging Zoonosis.

Nipah virus (NiV) infection is a viral disease caused by a Henipavirus, belonging to the Paramyxoviridae family, responsible for a zoonosis. The course of the disease can be very serious and lead to death. NiV natural hosts are fruit bats (also known as megabats) belonging to the Pteropodidae family, especially those of the Pteropus genus. Natural infection in domestic animals has been described in farming pigs, horses, domestic and feral dogs and cats. Natural NiV transmission is possible intra-species (pig-to-pig, human-to-human) and inter-species (flying bat-to-human, pig-to-human, horse-to-human). The infection can be spread by humans or animals in different ways. It is peculiar how the viral transmission modes among different hosts also change depending on the geographical area for different reasons, including different breeding methods, eating habits and the recently identified genetic traits/molecular features of main virus proteins related to virulence. Outbreaks have been described in Malaysia, Singapore, Bangladesh, India and the Philippines with, in some cases, severe respiratory and neurological disease and high mortality in both humans and pigs. Diagnosis can be made using different methods including serological, molecular, virological and immunohistochemical methods. The cornerstones for control of the disease are biosecurity (via the correct management of reservoir and intermediate/amplifying hosts) and potential vaccines which are still under development. However, the evaluation of the potential influence of climate and anthropogenic changes on the NiV reservoir bats and their habitat as well as on disease spread and inter-specific infections is of great importance. Bats, as natural reservoirs of the virus, are responsible for the viral spread and, therefore, for the outbreaks of the disease in humans and animals. Due to the worldwide distribution of bats, potential new reports and spillovers are not to be dismissed in the future.

Oronasal or Intramuscular Immunization with a Thermo-Attenuated ASFV Strain Provides Full Clinical Protection against Georgia 2007/1 Challenge

African swine fever (ASF) is a contagious viral disease of suids that induces high mortality in domestic pigs and wild boars. Given the current spread of ASF, the development of a vaccine is a priority. During an attempt to inactivate the Georgia 2007/1 strain via heat treatment, we fortuitously generated an attenuated strain called ASFV-989. Compared to Georgia, the ASFV-989 strain genome has a deletion of 7458 nucleotides located in the 5'-end encoding region of MGF 505/360, which allowed for developing a DIVA PCR system. In vitro, in porcine alveolar macrophages, the replication kinetics of the ASFV-989 and Georgia strains were identical. In vivo, specific-pathogen-free (SPF) pigs inoculated with the ASFV-989 strain, either intramuscularly or oronasally, exhibited transient hyperthermia and slightly decreased growth performance. Animals immunized with the ASFV-989 strain showed viremia 100 to 1000 times lower than those inoculated with the Georgia strain and developed a rapid antibody and cell-mediated response. In ASFV-989-immunized pigs challenged 2 or 4 weeks later with the Georgia strain, no symptoms were recorded and no viremia for the challenge strain was detected. These results show that the ASFV-989 strain is a promising non-GMO vaccine candidate that is usable either intramuscularly or oronasally.

Development of a quadruple PCR-based gene microarray for detection of vaccine and wild-type classical swine fever virus, African swine fever virus and atypical porcine pestivirus

BackgroundClassical swine fever (CSF), African swine fever (ASF), and atypical porcine pestivirus (APPV) are acute, virulent, and contagious viral diseases currently hampering the pig industry in China, which result in mummification or stillbirths in piglets and mortality in pigs. Diagnostic assays for the differentiation of infection and vaccination of CSFV, in addition to the detection of ASFV and APPV, are urgently required for better prevention, control, and elimination of these viral diseases in China.MethodsA quadruple PCR-based gene microarray assay was developed in this study to simultaneously detect wild-type and vaccine CSFV strains, ASFV and APPV according to their conserved regions. Forty-two laboratory-confirmed samples, including positive samples of 10 other swine viral diseases, were tested using this assay to confirm its high specificity.ResultsThis assay's limit of detections (LODs) for the wild-type and vaccine CSFV were 6.98 and 6.92 copies/µL. LODs for ASFV and APPV were 2.56 × 10 and 1.80 × 10 copies/µL, respectively. When compared with standard RT-PCR or qPCR for CSFV (GB/T 26875–2018), ASFV (MARR issue No.172), or APPV (CN108611442A) using 219 clinical samples, the coincidence was 100%. The results showed that this assay with high sensitivity could specifically distinguish ASFV, APPV, and CSFV, including CSFV infection and immunization.ConclusionThis assay provides a practical, simple, economic, and reliable test for the rapid detection and accurate diagnosis of the three viruses and may have good prospects for application in an epidemiological investigation, prevention, and control and elimination of these three diseases.

Effects of mat feeding on the growth performance, removal, and mortality of pigs after weaning.

Four experiments were conducted to determine the effect of mat feeding strategy on the growth performance, removal, and mortality of pigs after weaning. In exp. 1, 1,392 weanling pigs (initially 7.0 kg; approximately 24 d of age) were randomly allotted to 1 of 2 mat feeding treatments (mat feed vs. no mat feed). Overall, mat fed pigs had a tendency for improved ADG (P = 0.065) and G:F (P = 0.060) compared to pigs not offered mat feed. Mat fed pigs had fewer removals (P = 0.013) compared to pigs not offered mat feed. In exp. 2, 2,912 weanling pigs (initially 5.5 kg; approximately 21 d of age) were randomly allotted to 1 of 2 mat feeding treatments (mat feed vs. no mat feed). Overall, no differences in growth performance were observed. However, mat fed pigs had decreased (P < 0.026) final body weights compared to pigs not offered mat feed. This may be related to removal rates as mat fed pigs had fewer removals (P = 0.026). In exp. 3, 3,264 weanling pigs (initially 5.5 kg; approximately 21 d of age) were randomly allotted to 1 of 4 treatments in a 2 × 2 factorial with main effects of diet form (pellet or crumble) and mat feeding (mat feed vs. no mat feed). No interactions between diet form and mat feeding were observed. No differences were observed in overall growth performance for the main effect of mat feeding. Pigs offered pelleted feed had decreased overall ADFI (feed disappearance from the feeder and feed placed on the mat; P = 0.013) and improved G:F (P < 0.001) compared to pigs offered crumble feed. No differences were observed in removals or mortalities for the main effect of mat feeding or diet form. In exp. 4, 3,227 weanling pigs (initially 5.1 kg; approximately 21 d of age) were randomly allotted to 1 of 3 treatments consisting of mat feeding small (3.2 mm) pellets, mat feeding large (12.7 mm) pellets, or no mat feeding. Overall, no differences were observed in ADG or G:F. Mat fed pigs had increased ADFI (P < 0.001) compared to pigs not offered mat feed. Given the shorter duration of this experiment, the extra feed provided with mat feeding had a greater impact on overall feed usage than exp. 1, 2, and 3. No differences were observed in removals or mortalities. When combining the removal and mortality data for the four experiments, mat fed pigs had fewer removals (P = 0.002) compared to pigs not offered mat feed. In summary, mat feeding may encourage earlier feeding behavior, therefore reducing the removal rate of pigs post-weaning.

392 Young Scholar Award Talk: Strategies to Maintain Nutrient Intake, Reduce Weight Loss, and Improve Livability in Newly Weaned Pigs

Abstract Low feed consumption immediately after weaning disrupts nutrient intake and results in what is commonly known as a post-weaning growth check. While most pigs recover from this initial reduction in feed intake (FI), some pigs fail to successfully transition, leading to morbidity and mortality. Several pre- and post-weaning strategies have been suggested to improve post-weaning FI; however, as nursery pig mortality continues to increase across the industry there is need to optimize current intervention and management practices. Hence, we conducted 10 different experiments using 17,290 pigs. The first series of experiments evaluated the effect of mat, gruel, or creep feeding on nursery pig growth performance, morbidity, and mortality. Different sensory attractants offered pre- and post-weaning on the FI and body weight loss of nursery pigs after weaning were also assessed. Lastly, research evaluating the metabolic status of pigs when removed from general population pens was conducted which then expanded to research comparing sire lines with different growth curves to better understand the stress response of pigs post-weaning and the impacts on intestinal permeability, FI, and lifetime performance. Implementation of these strategies had limited effects on nursery pig growth performance; however, did show we can successfully reduce the percentage of pigs that lose weight after weaning, which may influence lifetime growth and removal rates. Specifically, creep and mat feeding can be used to reduce morbidity and mortality in the nursery. Nonetheless, attempts to maintain FI has minimal effects compared to genetic selection. Late maturing lines significantly reduced early nursery FI and growth compared with early maturing genotypes. In summary, nursery pig research needs to look beyond growth performance and focus on the behavior and health by nutrition interaction of pigs after weaning in order to continue identifying strategies to maintain continuity of nutrient intake and improve livability.

Co-Deletion of A238L and EP402R Genes from a Genotype IX African Swine Fever Virus Results in Partial Attenuation and Protection in Swine.

African swine fever virus (ASFV) is the causative agent of African swine fever (ASF), resulting in up to 100% mortality in pigs. Although endemic in most sub-Saharan African countries, where all known ASFV genotypes have been reported, the disease has caused pandemics of significant economic impact in Eurasia, and no vaccines or therapeutics are available to date. In endeavors to develop live-attenuated vaccines against ASF, deletions of several of the ~170 ASFV genes have shown contrasting results depending on the genotype of the investigated ASFV. Here, we report the in vivo outcome of a single deletion of the A238L (5EL) gene and double deletions of A238L (5EL) and EP402R (CD2v) genes from the genome of a highly virulent genotype IX ASFV isolate. Domestic pigs were intramuscularly inoculated with (i) ASFV-Ke-ΔA238L to assess the safety of A238L deletion and (ii) ASFV-Ke-ΔEP402RΔA238L to investigate protection against challenge with the virulent wildtype ASFV-Ke virus. While A238L (5EL) gene deletion did not yield complete attenuation, co-deletion of A238L (5EL) and EP402R (CD2v) improved the safety profile of the single deletions, eliciting both humoral and cellular immune responses and conferred partial protection against challenge with the virulent wildtype ASFV-Ke virus.

Effect of Dietary Supplementation of Finishers with Herbal Probiotics, Ascorbic Acid and Allicin on the Cost and Quality Characteristics of Pork

This study analyzed the effect of finishing diet supplementation with herbal probiotic preparation, ascorbic acid, and allicin on mortality rates of pigs, and longissimus lumborum (LL) and semimembranosus (SM) muscle quality, including the levels of cholesterol, macroelements and microelements. The experiment was carried out on 3614 hybrid pigs (equal share of gilts and barrows), of the offspring of PIC410 boars and DanBred sows (Landrace-Yorkshire), divided into two groups. The experimental group of pigs received Fermented Herbs Extract (Multikraft, Austria) enriched with probiotics (S. cerevisiae, L. casei, L. plantarum) in addition to ascorbic acid (E300) and allicin during the finishing period (95 days), while the control group was fed a typical finishing diet containing levels of antibiotics consistent with those used in commercial pig production. Our results showed a positive effect of supplementation with herbal probiotics, allicin and ascorbic acid in lowering finishing pig mortality and increasing pork quality as evidenced by higher pH (40 min post mortem in the SM muscle; 24 h and 48 h in the LL muscle), lower thaw loss, higher dry matter and intramuscular fat (IMF), and higher yellowness (b*) and chroma (C*) while maintaining similar carcass lean/fat content. However, results showed no effect of the supplements on the levels of cholesterol, macroelements, and microelements in the LL muscle, except for Mn, whose concentration was higher in the control group. Compared to barrows, the carcasses of gilts were characterized by a greater share of lean meat and lower backfat thickness, with similar physicochemical and functional characteristics of meat. The results also showed interactions between the groups of pigs (control and supplementation) and their sex in shaping L* and the content of ash, potassium and phosphorus in the muscles. In summary, from the point of view of production economics, the use of the analyzed supplements in the finishing feed and through fogging resulted in better health (no need for the use of antibiotics) and lower mortality of pigs, which ultimately resulted in better financial results. In addition, the use of these additives in pig fattening had a beneficial effect on meat quality.

Effective Selection for Lower Mortality in Organic Pigs through Selection for Total Number Born and Number of Dead Piglets.

Simple SummaryBreeders use breeding goals to guide genetic gain in a population in a desired direction. Breeding goals consist of economically interesting traits, in which each trait receives an economic value. For example, to increase the size of a piglet litter, breeders use a breeding goal that includes the trait “number of live piglets in a litter” for a specific day after birth. While the litter size is selected using the trait “number of live piglets,” it is composed of two traits: “total number born” and “number of dead piglets.” The current study used simulations to illustrate that selection for litter size could be improved by selecting for the latter two traits rather than the former. This approach corrects for the fact that these two traits are genetically related to each other, but they also have genetic differences. Further, splitting one trait into two traits allows breeders to focus on the specific elements of a trait. For example, organic pig breeders could select for better piglet welfare by splitting “number of live piglets” into two traits, giving a negative economic value to the number of dead piglets.Selection for the number of living pigs on day 11 (L11) aims to reduce piglet mortality and increase litter size simultaneously. This approach could be sub-optimal, especially for organic pig breeding. This study evaluated the effect of selecting for a trait by separating it into two traits. Genetic parameters for L11, the total number born (TNB), and the number of dead piglets at day 11 (D11) were estimated using data obtained from an organic pig population in Denmark. Based on these estimates, two alternative breeding schemes were simulated. Specifically, selection was made using: (1) a breeding goal with L11 only versus (2) a breeding goal with TNB and D11. Different weightings for TNB and D11 were tested. The simulations showed that selection using the first breeding scheme (L11) produced lower annual genetic gain (0.201) compared to the second (TNB and D11; 0.207). A sensitivity analysis showed that the second scheme performed better because it exploited differences in heritability, and accounted for genetic correlations between the two traits. When the second breeding scheme placed more emphasis on D11, D11 declined, whereas genetic gain for L11 remained high (0.190). In conclusion, selection for L11 could be optimized by separating it into two correlated traits with different heritability, reducing piglet mortality and enhancing L11.