Benchmark USA | 2024


STOP & SEE US AT WORLD PORK EXPO BOOTH: V251 TENT: G158 Topigs Norsvin USA Phone: (952) 641-0220 Email: 1.Innovative Leaders 2.Technical Support 3.Next Level Genetics 4.Progress in Pigs; Topigs Norsvin is the leading swine genetics company renowned for its innovative genetic solutions for cost-efficient pig production. Research, innovation and fast dissemination of genetic progress are cornerstones of our company. We are committed to help our customers to be successful in terms of production efficiency, meat quality, animal robustness and healthy, high productivity. 5.The Topigs Norsvin Team Topigs Norsvin [Top Pigz Nors Vin] noun When you think Topigs Norsvin, know you are recieving next level genetics and support. We have a team committed to empowering customers with the tools and resources they need to succeed in today’s competitive market.

Spring 2024 3 | | Published By: Media & Publishing & PigCHAMP, Inc. 1531 Airport Road, Suite 101 Ames, Iowa 50010 866-774-4242 Canadian Office: 90 Woodlawn Road West Guelph, ON N1H 1B2 888-248-4893 x293 PigCHAMP Product & Sales Manager Jayne Jackson Editor Andrew Joseph Sales & Support Specialist Hailey Arthur PigCHAMP Benchmarking Manager Susan Olson Sales Manager Andrew Bawden Marketing & Operations Denise Faguy Postmaster Please send returns to: 90 Woodlawn Road West Guelph, ON N1H 1B2 Benchmark Resources Online These articles, along with articles from past Benchmark magazines and additional expert information, can be found on the PigCHAMP website: If you have any additional information or suggestions for future articles please contact us at We will post these articles on the swine news pages, or include them in future issues of Benchmark. To receive weekly swine newsletters (free), email with the title Swine. All rights reserved. Editorial materials are copyrighted. Permission to reprint may be granted upon request. Cover: beshoy –, Yevhenii – Building bricks: tuomaslehtinen – 4 Benchmark Welcome 5 Potential “Benchmarks” for sow longevity 7 Beating the heat 11 A holistic approach to breeding for enhanced sow longevity 13 Swabs for precision 14 Guard the gate 16 Endgame 2024 18 USA 2023 year summary 19 Solution-based analysis for the long-haul 22 Gilts are the foundation for productivity and longevity 24 30 pigs/sow/year: Now what? 27 The good, the bad, and the ugly 30 2024 pork industry outlook 32 US pork exports a bright spot for producers

4 Spring 2024 These are turbulent times for pork producers. Because of that, in addition to benchmarking data, this year our theme for Benchmark magazine is “Building Blocks for the Long Haul, Bringing Longevity to the Farm.” Our goal is to provide swine producers with information related to several aspects of swine agri-business to help you tackle issues that ultimately have an impact on your business. Of course, we believe that data, particularly PigCHAMP benchmarking data, can assist you in making business decisions for your swine operation. It can help regardless if the decisions are related to the health and welfare of your animals, nutrition and production issues, or even labor and finance issues. The 2024 issue of Benchmark magazine also looks at technology to see how artificial intelligence might impact pork production in the future. PigCHAMP offerings for 2024 are also provided to help make your job smoother and easier. The updated PigCHAMP APP Intermittent Mode allows you to record data to your device wherever you are and then sync your records when connectivity is available. The PigCHAMP APP also allows you access to complete sow history and the ability to edit or delete events with real-time event validation. As noted, we know that these are turbulent times. But information and the interpretation of data can help you make solid business decisions that will help you weather the storm because we know you are in it for the long haul. If there is anything we can do to help, please let us know. Graham Dyer President & CEO PigCHAMP is proud to partner with these swine industry leaders. Our connectivity with these partners provides you with better, faster, and simpler information tools. 2024 BENCHMARK WELCOME Spring 2024 Graham Dyer WELCOME

High replacement rates for gilts and young sows have skewed current parity distributions on many farms towards younger females that haven’t reached their peak productivity. Identifying potential causes of this reduced longevity is challenging because many factors affect reproductive performance, and it is reasonable to speculate that these probably differ among farms and possibly within the same farm over time. Previous research using a technique called multiple regression analyses has shown that close to 50 percent of the variation observed in sow lifetime productivity on commercial farms can be explained by aspects of the litter from which the replacement gilt was weaned. These are commonly referred to as “litter of origin” traits and include things such as the number of pigs born, nursing, and weaned; birth and weaning weights; and weaning age (Figure 1). From a practical perspective, this means that if the difference between the most and least productive sows in a herd was, for example, 10 pigs weaned over six parities, then five of these were likely due to their neonatal management, or litter of origin. Collectively, these observations provide an opportunity for using production data collected between birth and weaning as a “benchmark” for estimating the future lifetime productivity of replacement gilts. Birthweight, weaning weight, and weaning age had a positive relationship with adult reproductive performance, while a negative relationship was present for the numbers of pigs born, nursing, and weaning, so any of these could be viewed as potential benchmarks for lifetime productivity. Of these, weaning weight appears to be one of the better candidates because: it is measured at the end of the neonatal period; is influenced to some extent by all the other litter of origin traits mentioned; and is relatively easy to collect. Accordingly, gilts from the same dataset used in the multiple regression analyses were placed into three equal groups based on their weaning weight: the upper, middle, and lower one-third of the entire population. Average weaning weights for these three groups were 21.5 lbs., 16.1 lbs., and 13.2 lbs., respectively, and at rebreeding after parity 3, corresponding percentages of sows still in production for each of these groups were approximately 60 percent, 40 percent, and 20 percent (Figure 2). It is important to recognize that neither the initial multiple regression nor the subsequent weaning weight analyses establish cause-and-effect relationships between litter of origin traits and lifetime productivity. While both are indicative of a strong positive relationship between the two, the true definition of a cause-and-effect relationship is when a management change is initiated first and then subsequent improvements in production occur in “response.” These types of evaluations are done quite often on commercial swine farms and typically involve collecting data before and after a management change is implemented. While there are obvious drawbacks to this approach, if the same management change is implemented across many different farms and the responses are very similar, then this provides good support for the conclusion that the management change caused the production effect. With regards to using weaning weight as a possible “benchmark” for sow lifetime productivity, a logical management change would be setting a minimum weaning weight for all replacement gilts. Females meeting this minimum would be managed accordingly post-weaning, while those that did not would essentially become market animals along with the maternal-line barrows. Once delivered to commercial farms, some measure of longevity, such as the parity at which sows are culled and/or the total number of pigs weaned per sow prior to culling, would need to be recorded. This is currently being done within some commercial production systems, and initial comparisons before and after the comparisons are shown in Table 1. For this dataset, the weaning weight minimum for potential POTENTIAL “BENCHMARKS” FOR SOW LONGEVITY An examination of today’s lifetime productivity expectations and litter of origin characteristics. By W.L. Flowers, Department of Animal Science, N.C.S.U., Raleigh, North Carolina PRODUCTION Figure 1. Relative Contribution of Litter Origin Traits to Lifetime Productivity Figure 2. Weaning Weight and Subsequent Sow Longevity Spring 2024 5

6 Spring 2024 replacement gilts was 14 lbs. and based on the analyses similar to those described earlier. This data has also been restricted to parity 3. This was done because several of the farms did not have quite enough observations from older parities to obtain a good enough estimate of what longevity means. The general trend for all the farms shown is for the proportion of sows still in production at rebreeding after parity 3 and the total number of pigs weaned over three parities to be statistically better after the weaning weight selection criteria was implemented at the multiplication farm. The degree to which these increased varied considerably among farms. This should not be surprising. If a litter of origin traits accounts for 50 percent of the variation in these traits, then the “other” 50 percent is most likely associated with the production environment on commercial sow farms. It is interesting to note that the farms with better lifetime production before screening replacement gilts for weaning weight tended to have smaller positive changes. For Farm No. 2 (in Table 1), the reproductive tracts of gilts delivered to the farm but never detected in estrus are being examined once these females are culled. Ovaries from most of the gilts examined prior to the use of the weaning weight criteria were small, avascular, and tended to contain low numbers of follicles and corpora lutea (Figure 3, top image). These characteristics are consistent with an underdeveloped, sub-functional ovary and are likely linked to poor growth and development during the neonatal period. In contrast, most of the ovaries from their counterparts after implementation appeared to be large, vascular, and contained large numbers of follicles and corpora lutea (Figure 3, bottom image). This suggests that the failure to detect estrus was probably technical (people) rather than biological (pigs). Although these preliminary results are encouraging, it would be unwise to make definitive conclusions or recommendations with regards to the value of using the weaning weight of gilts as a benchmark of their adult reproductive function, because things could be significantly over parities three through six. Interestingly, the most important aspect of this study may very well be the process rather than the result. The process is the following: a qualitative analysis that identifies possible benchmarks; a quantitative assessment to establish specific criteria for a given “benchmark”; and an implementation prospectively to determine the actual responses. It is quite possible and probable that all of these could differ among different production systems or within the same production system over time. POTENTIAL “BENCHMARKS” FOR SOW LONGEVITY By W.L. Flowers, Department of Animal Science, N.C.S.U., Raleigh, North Carolina PRODUCTION Table 1. Preliminary Data from Commercial Sow Farms Before and After Implementation of Weaning Weight Selection Criteria for Replacement Gilts Corpora Albicantia/Only a Few CL/Luteal Cyst Corpora Lutea/Corpora Albicantia Normal follicular growth and ovulation - missed estrus Low Ovulation rate Sows rebred after Parity 3 (%) No Selection Criteria No Selection Criteria Weaning Weight > 14 lbs. Weaning Weight > 14 lbs. Total Pigs weaned Parities 1 - 3 Farm 1 22.7 34.3 27.1 30.7 18.4 30.1 27.1 28.3 40.3 46.3 31.3 33.2 32.3 40.4 30.7 32.4 42.4 49.4 32.8 34.1 31.2 40.1 29.4 31.7 2 3 4 5 Average Dr. William L. Flowers joined the Animal Science Department at North Carolina State University in 1987, and is currently a William Neal Reynolds Distinguished Professor. His research program focuses on improving fertility in swine and has resulted in over 170 peer-reviewed publications and 485 popular press and extension articles. Dr. William L. Flowers Figure 3. Ovarian Morphology from Gilts with no recorded Estrus

Spring 2024 7 Within the pork industry, heat stress poses a significant threat to overall pig production, impairing health, productivity, and well-being at all life stages. Understanding the mechanisms and implications of heat stress is crucial for producers to mitigate its effects and ensure proper animal well-being and industry sustainability. Postnatal heat stress occurs when pigs are exposed to high temperatures, leading to physiological and behavioral changes that can impact their growth and overall health (Figure 1). Heat stress can cause a reduction in feed intake, meaning slower growth and decreased productivity. There may also be a behavior change—more time lying down and less activity—to dissipate heat and reduce metabolic heat production. Heat stress during pregnancy can have an even more profound effect on pig production. Sows exposed to high temperatures during gestation may experience reduced reproductive performance, including lower conception rates and increased embryonic mortality. Furthermore, heat stress during pregnancy can affect the prenatal development of their piglets, leading to lower birth weights, higher mortality rates after birth, and long-term negative effects on piglets throughout their postnatal life (Figure 2; Johnson and Baumgard, 2019; Johnson et al., 2020). Heat stress research has highlighted the importance of managing thermal comfort in pig facilities. By providing adequate ventilation and cooling systems and understanding the thermal requirements of the modern pig, producers can help mitigate the negative effects of heat stress on their animals. Nutritional strategies of adjusting feed formulations and supplementing diets with electrolytes, trace minerals, and antioxidants can support pigs’ health and performance during periods of heat stress. Furthermore, genetic and genomic selection for improved heat stress tolerance may be an effective strategy to improve resilience and reduce the negative effects of heat stress on pigs and their developing offspring. Technology and Heat Stress Mitigation Mitigating heat stress in pigs requires a multifaceted approach to address management practices and environmental conditions. BEATING THE HEAT: Keeping pigs cool and comfortable on the farm Dr. Jay S. Johnson, PhD, Dr. Luiz F. Brito, PhD, and Dr. Allan P. Schinckel, PhD PRODUCTION Figure 1. Effects of heat stress on physiological responses of pigs. Adapted from Johnson et al. (2015a). Figure 2. Postnatal phenotypic changes in pigs exposed to in utero heat stress. Adapted from Johnson and Baumgard (2019).

8 Spring 2024 Producers can employ various strategies to create a comfortable environment for their pigs during times of heat stress and minimize the negative effects on pig performance and well-being. The first step in mitigating heat stress is understanding what environmental conditions can cause pigs to become heat-stressed. Decision-support tools in the form of smartphone applications such as HotHog (Figure 3) are available to producers and allow for real-time predictions of thermal comfort and stress levels. These predictions are based on location and production stage, allowing pig producers to make informed decisions about how to best protect their pigs from heat stress. By leveraging technology and data-driven insights, pig producers can implement proactive measures to minimize the negative effects of heat stress on their operations. Once heat stress risk levels can be identified, one of the most effective ways to mitigate heat stress on swine farms is through the use of conductive heat loss cooling systems. Cooling pads, such as those developed by Purdue University (Figure 4), can aid in dissipating heat (Figure 5A). This can result in downstream positive impacts on piglet growth under heat-stress conditions (Figure 5B). Proper ventilation is another essential component of heat stress mitigation in pig farms. Ventilation systems help remove excess heat, moisture, and airborne contaminants from pig facilities, creating a healthier and more comfortable environment for the animals. By optimizing airflow and temperature distribution, producers can ensure that pigs have access to fresh air and reduce the risk of heat stress. Overall, mitigating heat stress in pig farms requires a comprehensive approach that addresses environmental conditions, management practices, and incorporates technological solutions. By implementing cooling systems, optimizing ventilation, and leveraging technology to monitor and manage heat stress, producers can create a more comfortable environment for their pigs, thereby improving productivity and well-being during times of heat stress. Nutrition and Heat Stress Management Nutrition is key to managing heat stress in pig production. During periods of high temperatures, pigs may experience changes in feed intake and nutrient requirements, which can impact their growth and overall health. Therefore, farmers must adjust their feeding strategies to ensure that pigs receive adequate nutrition to support their well-being during heat stress. One key consideration in nutrition and heat stress management is maintaining the overall hydration levels of the pigs. Heat-stressed pigs may drink more water to regulate body temperature and replace fluids lost through panting. Producers should ensure that pigs have access to clean and fresh water at all times to prevent dehydration and support their physiological needs during periods of heat stress. Furthermore, water-delivered supplements have been shown to be effective in helping pigs recover from heat stress events. Optimizing feed formulas can help support pigs’ health and performance during heat stress. Feeds supplemented with electrolytes, trace minerals, and antioxidants can replenish lost nutrients and support pigs’ physiological functions under heat-stress conditions. In addition, attention should be paid to the energetic requirements of pigs exposed to heat-stress conditions. For example, although ad libitum-fed growing-finishing pigs often grow slower under heat-stress conditions, heat-stressed gestating gilts that are limit-fed following routine production practices grow faster when compared to those housed under thermoneutral conditions (Figure 7). This is likely due to the reductive effects of heat stress on the maintenance costs of pigs (Figure 8), which may result in a more positive energy balance for heat-stressed versus thermoneutral-exposed pregnant gilts that are limit-fed (Figure 9). Pig producers can work with nutritionists to adjust feed formulations and ensure that pigs receive balanced diets that meet their nutritional needs during periods of high temperatures. Lactating sows are particularly susceptible to heat stress, as selection for increased sow productivity has increased their heat production by over 50 percent in the past 40 years. As a result, high environmental temperatures negatively impact BEATING THE HEAT Dr. Jay S. Johnson, PhD, Dr. Luiz F. Brito, PhD, and Dr. Allan P. Schinckel, PhD PRODUCTION Figure 4. The HotHog home screen (left); management and mitigation screen (right). Available for free in the Apple App Store or Google Play. Figure 5. A lactating sow using an electronically controlled sow cooling pad.

Spring 2024 9 their milk production and, consequently, affect the growth and development of nursing piglets. Heat-stressed sows can also have delayed estrus after weaning and reduced conception rates. Producers should pay close attention to the nutritional needs of lactating sows during heat stress and provide supplemental feeds to support milk production and piglet growth. However, it is important to note that nutritional support may not always result in improved piglet growth under heat stress conditions, as heat stress has a direct and negative impact on milk production independent of improved feed intake (Black et al., 1993; Johnson et al., 2021). Therefore, nutritional strategies should be coupled with appropriate cooling technologies for maximum benefit. Harnessing Genetics & Genomics to Combat Heat Stress Genetic selection offers promising opportunities for developing pig populations that are more heat-stress resilient. By developing genomic prediction models and identifying genetic markers associated with heat tolerance and thermoregulatory efficiency, researchers can breed pigs with enhanced resilience to high temperatures and reduce the negative effects of heat stress on animal well-being and productivity. Through selective breeding programs, producers can prioritize traits related to heat tolerance and incorporate them into their breeding objectives. This may include selecting breeding stock with superior heat stress resilience based on thousands of genomic markers, which is already a common practice in pig breeding programs. By selecting heat-tolerant pigs, producers can develop populations of pigs that are better adapted to hot climates and less susceptible to the negative effects of heat stress while still maintaining high productivity levels. Breeding program effectiveness requires the identification of traits that are heritable, repeatable, and can be measured in a large number of individuals in a cost-effective and non-invasive manner. Recent research has identified multiple indicator traits that can be used in breeding programs, including automatically-recorded vaginal temperature, skin temperature, and respiration rate (Johnson et al., 2023; Freitas et al., 2023). In addition to the definition of novel traits for breeding purposes and the development of genomic prediction models, research into the genetics of heat stress tolerance in pigs has identified several candidate genes and genetic markers associated with heat tolerance and thermoregulatory efficiency. By leveraging this genetic and genomic information, researchers and producers can accelerate the breeding process and develop more heat-tolerant pig populations that exhibit improved resilience to high temperatures and heat-stress conditions. Research by our group has shown that various indicators of heat stress response are moderately heritable and that genomic prediction of heat stress tolerance can clearly distinguish more heat-tolerant animals from more heat-sensitive animals (Figure 10; Freitas et al., 2023). BEATING THE HEAT Figure 6. The effects of an electronically controlled sow cooling pad on (A) lactating sow body temperature, and (B) litter weaning weights Adapted from Johnson et al. (2021). Figure 7. (A) Feed intake and (B) average daily gain (ADG) of gestating gilts limit fed 1.82 kg per day and exposed to heat stress (HS) or thermoneutral (TN) conditions. Adapted from Byrd et al. (2022). Dr. Jay S. Johnson, PhD, Dr. Luiz F. Brito, PhD, and Dr. Allan P. Schinckel, PhD PRODUCTION

10 Spring 2024 By utilizing genomic selection techniques, researchers and breeders can help enhance the efficiency and precision of breeding programs and develop more heat-tolerant pig populations more rapidly and effectively, as genetic progress is permanent and cumulative over generations. In conclusion, genetic and genomic selection offer promising opportunities for developing pigs that are more heat-stress resilient. By identifying genetic markers associated with heat tolerance and developing genomic prediction models to calculate the genetic merit of breeding animals (candidates for selection), researchers and producers can develop more heat-tolerant pig populations that are better adapted to hot climates and less susceptible to the negative effects of heat stress while maintaining sustainable production and reproduction levels. By utilizing continued research and innovation, genetic selection can play a critical role in the improvement of the resilience and sustainability of pig production systems in the face of climate change and environmental challenges. Conclusions and Future Directions Addressing heat stress in pig production necessitates a multifaceted approach that needs to encompass management practices and technological innovations, nutritional considerations, and genetic and genomic selection. The research underscores the significance of understanding the physiological and behavioral impacts of heat stress across different life stages, from postnatal growth to prenatal development. Mitigation strategies such as adequate ventilation, cooling systems, and optimized nutrition are pivotal for maintaining pig health and productivity during periods of elevated temperatures. Moreover, harnessing genetic and genomic advancements presents promising avenues for developing more heat-tolerant pig populations, offering long-term resilience against climatic variations. Continued advancements in these areas hold the key to fostering sustainable pig production systems resilient to the challenges posed by heat stress and climate change. As we move forward, collaborative efforts between researchers, producers, and technological innovators will be crucial in ensuring the well-being and productivity of pigs in a changing environment. Dr. Jay S. Johnson is the Supervisory Research Animal Scientist (Research Leader) of the USDA-ARS Livestock Behavior Research Unit in West Lafayette, IN USA specializing in stress and nutritional physiology. Dr. Jay S. Johnson, PhD Figure 8. Maintenance costs of growing and finishing pigs exposed to heat stress (HS) or thermoneutral (TN) conditions. From Johnson et al. (2015b, c). Figure 9. Energy utilization for growth vs maintenance costs in limit-fed gestating pigs exposed to heat stress (HS) or thermoneutral (TN) conditions. Figure 10. Estimated breeding values for heat tolerance and heat stress sensitivity in lactating sows. Adapted from Freitas et al. (2023). Dr. Allan P. Schinckel is professor of animal science in swine genetics and modeling with BS from Iowa State and MS and PhD from the University of Nebraska. He teaches course in pork production, design of breeding programs and modeling of pig growth and nutrient requirements. Dr. Schinckel has recently been involved in heat stress research and the use of electronic cooling pads for boars and sows. Dr. Allan P. Schinckel, PhD Dr. Luiz Brito is an Associate Professor of Quantitative Genetics and Genomics in the Department of Animal Sciences at Purdue University. Luiz also holds Adjunct Faculty positions at the University of Guelph in Canada and at the University of Nebraska-Lincoln. Dr. Luiz F. Brito, PhD BEATING THE HEAT Dr. Jay S. Johnson, PhD, Dr. Luiz F. Brito, PhD, and Dr. Allan P. Schinckel, PhD PRODUCTION

A HOLISTIC APPROACH TO BREEDING FOR ENHANCED SOW LONGEVITY The greater the sow longevity, the more litters can be obtained, increasing farm profits. Dr. Jenelle Dunkelberger PRODUCTION As an industry, we have realized the steady increase in sow mortality throughout the past decade and employed various efforts to respond to this critical production issue. Despite the number of hours and dollars invested in addressing sow mortality, identifying solutions continues to be a challenge. This is likely due to many factors, such as inconsistencies or incomplete recording of removal reasons at the farm, the multifactorial nature of this trait (including both genetic and non-genetic causes), and numerous confounding factors across farms that severely limit, or even disable, the ability to properly analyze farm data. At Topigs Norsvin, we are passionate about exploring the genetic basis for (general) sow longevity as well as the leading, specific causes of sow death loss. While numerous reasons for sow death loss are reported, 83 percent of sow mortality events can be explained by one of the following reasons: 1.) unknown/other; 2.) feet/leg issues; or 3.) vaginal/uterine prolapse (Ross, 2019). Addressing these issues through the breeding program, however, is not trivial. Unknown/Other Genetic improvement starts at the top of the production pyramid. At this level, extensive data is collected on the most genetically elite animals. This data includes information for a diverse set of traits as well as genetic information for each individual. Sow longevity, however, is not among the traits that are measured at these nucleus locations. Due to the need to continuously evaluate the latest generation of animals, the sow replacement rate at nucleus farms is intentionally higher than standard production practices. For this reason, an individual animal’s genetic potential for longevity cannot be evaluated. As an alternative, Topigs Norsvin has a partnership with a large commercial farm in the US, where detailed removal information and genetic information are captured for each female. By linking these animals to others in the database via their genetic relatedness, data collected at the commercial level can be used to estimate the genetic merit of individuals for longevity and related traits at the nucleus level. This is the process that Topigs Norsvin uses to drive genetic improvement in sow longevity. Selection for enhanced sow longevity has been underway for over a decade, facilitated by selection based on two different traits: longevity to parity 2 and longevity to parity 5. This approach of selecting for enhanced (general) longevity is the only way to address the number one sow-death-loss reason when the cause of death is not known. Feet/Legs While selection for enhanced general longevity is used to reduce genetic susceptibility to any or all sow mortality reasons, we also select against the second and third-leading causes of sow mortality—feet/leg issues and vaginal/uterine prolapse, respectively—to complement this approach. At Topigs Norsvin, data is recorded for more than 30 structural traits. Of these traits, special emphasis is placed on phenotyping and selecting against osteochondrosis, given that osteochondrosis is a main cause of lameness. Selection against osteochondrosis has been underway since 1990. At that time, osteochondrosis was scored by evaluating joints post-mortem. This process involved scoring both the medial and lateral condyles of the distal humeral and femur joints (of both legs) to obtain osteochondrosis scores at a total of eight different locations. In 2003, this method was replaced by assigning osteochondrosis scores based on CT images. Now, selection against susceptibility to osteochondrosis is facilitated using a combined score, calculated as the sum of scores assigned using CT images across all eight locations (Aasmundstad et al., 2013). It is important to realize that, because pigs are most susceptible to osteochondrosis at a young age, an unfavorable relationship exists between fast (early life) growth and susceptibility to osteochondrosis (Figure 1). This natural, antagonistic relationship presents a problem for breeders. If selecting for an increased growth rate, susceptibility to osteochondrosis and, therefore, lameness will also increase. For this reason, if selecting for faster growth, explicit selection against susceptibility to osteochondrosis must also be performed. Vaginal/Uterine Prolapse The third-most common sow removal reason is vaginal/uterine prolapse, commonly referred to as pelvic organ prolapse, or POP. There are many potential causes of POP, which may be classified as being either environmental (non-genetic) or genetic in nature. To investigate the potential role of genetics in susceptibility to POP, we launched an investigation in 2020 using data collected from more than 16,000 sows from a single commercial multiplication farm in the US. This was an extremely valuable dataset, consisting of complete pedigree information, genomic data, and detailed removal information for each female in inventory for the past decade. As a first step towards deciphering the potential role of genetics in susceptibility to POP, a genetic analysis was conducted using three generations of pedigree data. The results of this analysis showed that POP is heritable at 22 percent (Stevens et al., 2021; Dunkelberger et al., 2022). In response to these findings, POP was added to the selection index in January 2021. Therefore, explicit selection against susceptibility to POP has now been part of Topigs Norsvin’s breeding program for the last three years. This was the first study to show that POP has a genetic basis. To investigate this further, a follow-up study was conducted in partnership with Vishesh Bhatia, Dr. Jack Dekkers, and Dr. Jason Ross of Iowa State University. The same dataset that was used for the initial analysis was also used for this follow-up evaluation, 2 Topigs Norsvin Figure 1: Antagonistic relationship between early life growth (quantified as the number of days in the growing phase) with osteochondrosis. 2 -0.74 -0.31 -0.39 -0.02 0 66 110 154 198 0 220 Live weight (lbs.) Genetic correlation (days in phase, osteochondrosis) Figure 1. Antagonistic relationship between early life growth (quantified as the number of days in the growing phase) with osteochondrosis. Spring 2024 11

12 Spring 2024 Dr. Jenelle Dunkelberger PRODUCTION A HOLISTIC APPROACH TO BREEDING FOR ENHANCED SOW LONGEVITY however, this time using genomic data rather than pedigree data to account for relatedness between individuals. Results of this follow-up study showed that POP was even more heritable (35 percent) than previously realized (22 percent) (Figure 2) (Bhatia et al., 2023). Next, an analysis was conducted to characterize the genetic basis of POP. Results of this exercise showed that there are, likely, a few major genes that impact susceptibility to POP, including genes with roles in pelvic organ support, smooth muscle tissue, calcium level, and even susceptibility to uterine prolapse in other species. However, in general, genetic susceptibility to POP appears to be due to many genes, each with small effects on POP (Bhatia et al., 2023). Taken together, the results of this collaborative study validated the decision to add POP as a new trait to the selection index, which is an encouraging opportunity to address a major reason for sow death loss through the breeding program. The heritability estimate of 35 percent, referenced above, indicates that 35 percent of the total variation impacting susceptibility to POP is due to genetics. This estimate also implies that the remaining 65 percent of the variation in susceptibility to POP is due to environmental or non-genetic factors. Therefore, genetic solutions alone will not solve POP. Rather, reducing the incidence of POP will require addressing both genetic and non-genetic factors impacting this trait. Although numerous non-genetic factors have been proposed and discussed by industry experts, determining the effect that these factors have on susceptibility to POP is complicated. Many suspected non-genetic factors are explained in the Pelvic Organ Prolapse Project Final Report (Ross, 2019), a summary of analyses conducted by the Iowa Pork Industry Center, led by Dr. Jason Ross. Results from this project showed that of the 20+ variables evaluated using data collected from more than 100 US farms, only water treatment, bump feeding strategy, perineal score, and body condition during late gestation were significantly associated with susceptibility to POP (Ross, 2019). We opted to select two of these variables, the perineal score and the body condition score, for further evaluation in a designed research trial. For this research trial, data was collected on approximately 4,000 TN70 F1 parent females from two different sow farms within the same system. Data was recorded for each female upon entry into the farrowing unit, including the perineal score, body condition score, and caliper score. Each instance of POP was also recorded. However, due to the limited number of POP observations, the perineal score was analyzed as the response variable for all analyses conducted. Results show that body condition score and caliper score were highly and significantly associated with a perineal score, where the thinner the sow, the higher the incidence of the non-ideal perineal score (i.e., moderate to high risk of developing POP) (Dunkelberger, 2024). This finding agrees with the results of the Pelvic Organ Prolapse Project (Ross, 2019), where thin sows were more susceptible to POP. Ultimately, non-genetic solutions, such as proper management of body condition during late gestation, must be used to complement genetic selection for reduced susceptibility to POP. Overall Conclusions Sow mortality continues to be a major concern for the US swine industry, likely because sow mortality appears to be due to any number of complex, underlying causes. At Topigs Norsvin, we take a holistic approach to improving sow longevity by addressing the leading causes of sow death loss through the breeding program. We address the top reason for sow death loss (unknown/other) by breeding for enhanced (general) longevity. The second and third-leading causes (feet/leg issues and vaginal/uterine prolapse, respectively) are addressed via explicit selection for structural traits, osteochondrosis (a leading cause of lameness), and susceptibility to vaginal/uterine prolapse. Results presented in this article show that overall sow longevity, as well as these leading, specific causes of sow death loss, while heritable, are only partially under genetic control. This means that the majority of variation in these traits is due to environmental factors. Therefore, genetics is only one piece of a strategy needed to improve sow longevity. Genetic selection, in combination with non-genetic solutions, will be required to address this critical, multifactorial issue in US swine production. Jenelle holds a Bachelor’s degree from Northwestern College in Orange City, Iowa, and earned a PhD in Genetics from Iowa State University as a USDA National Needs Fellow. She has papers and conference proceedings on animal genetics topics, such as the role of host genetics in response to disease challenge. She continues this area of research as leader of the Global Health & Behavior Platform for Topigs Norsvin. Dr. Jenelle Dunkelberger 3 Topigs Norsvin Genomic-Based Heritability Estimate Pedigree-Based Heritability Estimate Figure 2: Heritability of pelvic organ prolapse estimated using pedigree (A) vs. genomic (B) data. A B Figure 2. Heritability of pelvic organ prolapse estimated using pedigree (A) vs. genomic (B) data.

Spring 2024 13 [Note that this article is a re-written and shortened version taken from its original published form in Frontiers in Veterinary Science by the original author.] Despite advancements in understanding the porcine reproductive and respiratory syndrome virus and increased efforts to prevent, control, or eliminate it, the porcine reproductive and respiratory syndrome virus (PRRSV) still causes significant issues for the pig farming industry worldwide (Cheng et al., 2022; Holtkamp et al., 2013; Nathues et al., 2017). Weaning-age pigs play a significant role in spreading PRRSV and are the subpopulation of choice for surveilling PRRSV in breeding herds (Holtkamp et al., 2021). While traditional blood sampling is ideal for monitoring the virus, alternative sample types, such as swabs, are easier to collect and are frequently submitted to US veterinary diagnostic laboratories for PRRSV investigation. However, there are no guidelines on how these swab samples could be used for PRRSV surveillance in specific scenarios. This study sought to compare PRRSV detection rates by reverse transcription real-time polymerase chain reaction (RT-rtPCR) in swabs and serum obtained from weaning-age pigs with the end goal of determining comparable sample sizes. Methods Three eligible PRRSV-positive herds in the midwestern United States were selected for this study—666 pigs were sampled for serum, nasal swabs (NS), ear-vein blood swabs (ES), and oral swabs (OS). All samples were tested for PRRSV RNA by RT-rtPCR at a National Animal Health Laboratory Network (NAHLN)-accredited veterinary diagnostic laboratory. The binary outcome (RT-rtPCR positive or negative) was obtained for each sample tested, and the distribution of the cycle threshold (Ct) values was evaluated using box plots. Cohen’s Kappa analysis (McHugh, 2012) was used to assess agreement in the RT-rtPCR results between all paired combinations of sample types. Sensitivity and specificity values were obtained for each swab sample using serum as the reference. Appropriate sample sizes were then calculated using the obtained sensitivity and specificity values. Results As anticipated, serum samples exhibited the highest RT-rtPCR positivity rate, with 96 pigs testing positive. These serum samples also demonstrated the lowest median Ct value (Figure 2). Of the 96 pigs testing positive by serum, 80 tested positive by ES and OS, while 72 tested positive by NS. Among the swab sample types, ES showed the lowest median Ct value, whereas NS showed the highest. It was also observed that the lower the RT-rtPCR Ct in serum samples, the higher the likelihood that any swab sample from that pig will be positive. Cohen’s Kappa analysis revealed near-perfect agreement (≥ 0.81) between all paired combinations of sample types. Notably, a small number of pigs tested positive in swab samples but negative in serum: seven by OS, two by ES, and four by NS. The recommended sample sizes for each sample type are presented in Table 1 below. For more sample size recommendations at different prevalence scenarios, please refer to the “Serum and swabs” tab on the free fieldepi sample size calculator for “PRRSV surveillance,” located at Conclusion When practitioners opt to use individual pig antemortem samples rather than the more cost-efficient population-based sampling SWABS FOR PRECISION You can use swabs for PRRSV surveillance in weaning-age pigs with precision. Onyekachukwu Henry Osemeke HEALTH/WELFARE Figure 1. A pictorial summary of samples collected from each piglet. A: Serum collection B: Ear-vein blood swab collection C: Oral swab collection D: Nasal swab collection. Figure 2. RT-rtPCR Ct distribution by sample type. (ES: ear-vein blood swabs; NS: nasal swabs; OS: oral swabs; Srm: serum). The red dashed line represents the RT-rtPCR Ct cut-off value for test positivity. Continued on page 26

14 Spring 2024 GUARD THE GATE A focus on biosecurity at the loading dock can impact animal health and productivity. Jeb Gent HEALTH/WELFARE Today’s pork producers know that biosecurity is essential in every aspect of pig production. While the concept is simple—preventing the spread of pathogens coming into or leaving a farm—the many facets of an effective biosecurity program can be overwhelming and difficult to measure. Taking a focused approach to analyzing biosecurity risks at an operation, prioritizing potential impact, and developing plans for continuous improvement are all key methods for keeping pigs healthy and productive. Effective biosecurity systems include establishing protocols and selecting products that fit your operation’s needs, then training personnel and building a culture to ensure that protocols are carried out consistently and with integrity. Biosecurity Matters for Animal Health and Bottom Line While the return on investment for biosecurity practices is not as concise or easy to measure as other areas of an operation, such as feed costs or vaccinations, we know that achieving the ultimate goal of delivering healthy, full-value pigs through to finishing is only possible when effective biosecurity is in place. Your operation’s longevity relies on it. Health issues in a herd reduce animal productivity, drain profits, and increase the lateral spread of viruses, creating a spiral that is difficult to get out of. The cost of high-profile viruses such as porcine reproductive and respiratory syndrome virus (PRRSv) and porcine epidemic diarrhea virus (PEDv) is well documented and captures headlines. The annual cost of PRRSv in the US national breeding and growing-pig herd was estimated at $664 million in 2011, and PEDv has been estimated to cost the industry $27 million a year. Pork producers also face significant impacts from pathogens that don’t make the headlines but tend to persistently and consistently cause problems in finishing barns. A survey conducted by Holtkamp et al. found that the most common and challenging pathogens in finishing herds in the US were reported to be swine influenza, Mycoplasma hyponeumoniae, and PRRSv. In short, the swine industry battles a large number of pathogens. It can pay dividends to keep them from the production cycle. How do Pathogens Enter the Finishing Herd? The list of potential entry points for pathogens into a finishing herd is long and includes nearly every aspect of an animal’s life and care. For example, research has found that an estimated 55 percent of growing pig groups that are negative for PRRSv at placement are positive for the virus at marketing. This suggests that the virus was introduced sometime during the growing period, which can cause losses of approximately $2.29 per pig from higher mortality and slower growth. Viruses require a vector or pathogen-carrying agent, such as an object, animal, person, dust, or even air, to carry a virus into the finishing herd for possible exposure. Potential hazards include: • Animal movements, including weaned pig removal and introduction to the finishing barn, loading out finished pigs, and removal of mortalities; • Deliveries and removals, including feed and feed ingredients, propane and fuel, garbage removal, new tools and supplies, and manure removal; • People movements, including on-farm employee entry, repair and service personnel entry – both inside and outside a barn, veterinarian and other vendor entry; • Other animals and insects, including rodents; • Air and water entry through ventilation and the opening of barn doors. The transportation process is especially challenging, with the potential for exposure at every step. There is a need for biosecurity to be understood and prioritized by multiple parties. Don’t Forget the Loading Dock While there are many sources of possible pathogen entry, one area that represents a great risk but is often ignored is the loading dock. Loading out pigs headed to the processing plant can be seen as the end of those animals’ potential exposure, but remember that all other pigs in the building are at risk from the pathogens that find their way into the barn while their former barnmates are leaving. Each time the barn door opens, viruses can travel in on dust or on contaminated boots, clothing, or personal objects. The loadout area of a barn can also produce a “vacuum effect” that sucks in air, along with contamination from the outside or the trailer, when doors are opened. This effect increases when outdoor temperatures are warmer due to higher fan ventilation speeds. One of the most eye-opening demonstrations of potential risk in the loadout process is in Dr. Holtkamp’s 2020 trial using Glo Germ fluorescent powder. A mixture of fluorescent powder, wood chips, and obstetrics gel was placed just inside the rollup door of the livestock trailer. As pigs were loaded out, the loadout chute had a “consistently high level of contamination” from what the researchers determined were several sources. As pigs lunged up the chute and into the trailer, they lost traction, causing bedding and contamination to be thrown back onto the chute, whereupon load crew member boots, Application of a hygiene powder or similar product can enhance biosecurity in finishing barns, loading chutes, and livestock trailers. Source: Ascension Ag

Spring 2024 15 Jeb Gent HEALTH/WELFARE GUARD THE GATE sorting panels, and pig handling tools all could have spread contaminated particles. The research confirmed that the traditional loading protocol with crew members walking throughout the barn—bringing finished pigs from pens down the center alley and loadout alley, then back through the alleys to repeat the process with other pens—caused the contaminated particles from the trailer to be tracked back into the loadout alley, center alley, and even nearby pens. Ultimately, if pigs are loaded onto a dirty livestock trailer or an improperly cleaned load chute is used, the risk of introducing new contaminants into the barn is dramatically increased. Stepping up Biosecurity on the Loading Dock Reviewing protocols and adding new practices for loading out finished pigs is a good start to minimizing the risk of pathogens entering barns. I’d recommend three areas to start with: 1. Develop and follow protocols for washing trailers. Trailers that have been effectively cleaned before arriving at a barn are the first step in minimizing the potential for pathogens to enter a building. Establish a written protocol for your barns and operations, and then make sure that all drivers—whether employees or contractors—abide by that protocol. 2. Implement a “staged loading” process. In the trial that we highlighted earlier, Dr. Holtkamp also compared the contamination between a conventional loading process and a staged loading process. Instead of just one line of separation in conventional loading, with the truck driver staying inside the trailer and all other crew members moving throughout the barn, a staged loading process establishes two lines of separation. Using a second line of separation between the loadout alley and center alley requires one person to stay in the load out alley to move pigs to the chute, while other person- nel move the animals out of the pens and down through the center alleyway. The study showed that staged loading reduced the amount of contamination transfer to the barns com- pared to conventional loading, with the second line of separation providing an additional layer of biosecurity during the loading process. 3. Apply hygiene powder or something similar. The application of a hygiene powder or barn lime can provide another layer of biosecurity in trailers and finishing barns. These powders can reduce moisture and pathogen load and create a barrier between vectors and viruses, with the added advantage of covering cracks, hinges, and other areas that can be hard to reach in standard cleaning practices. When choosing a prod- uct, make sure that it meets the specifications for your barns and protocols, including application timing, safety around animals, and expectations for antiviral and anti- bacterial properties. ChloraSorb livestock hygiene powder from Ascension Ag is one option that can be used in hard-to-clean or wet environments and provides research-proven perfor- mance to support animal health and facility biosecurity. The best starting point is to work closely with your veterinarian to develop biosecurity protocols tailored to your operation, then ensure that employees, contractors, and service providers follow the protocols to help protect your pigs, barns, and farm, as well as the US pork industry, from outbreaks and productivity challenges. Illustration of conventional loadout and staged loadout processes. A second line of separation in the staged loadout process provides an additional layer of biosecurity during the loading process. Source: Reprinted from the “Evaluation of a staged loadout procedure for market swine to prevent transfer of pathogen contaminated particles from livestock trailers to the barn” article in the Journal of Swine Health and Production with permission from the author. Jeb Gent is the co-founder of Ascension Ag, a livestock biosecurity company located outside of Ames, Iowa. Solving niche biosecurity challenges on swine and poultry farms is a passion for Jeb. He loves helping farmers save animals, increase profits, and improve production processes. He and his wife have four young children and reside in Ames. In his free time, he enjoys family, friends, church, exercise, and farming. Jeb Gent