Progress 09/01/23 to 08/31/24
Outputs
Target Audience:Producers Veterinarians Allied Industries Extension Staff Scientists Changes/Problems:Challenge - Engagement of the Extension team has been moderate This remains an obstacle. IPIC leadership continues to be enthusiastic, but enthusiasm from Extension Agents is moderate. Again, discussion is good, and in meetings, enthusiasm is high, but translating those conversations to tangible Extension products continues to underwhelm. Solution - I will continue to work with the Extension team and continue to voice my enthusiasm for their work and efforts. I will also continue to seek ways, independent of the Extension team, to reach producers. Challenge - Aim 2 and Extension Aim 1 are moving slower than expected. ?The production dataset we have proved to be more complicated than anticipated. Importantly, a student was dedicated to these analyses and is continuing to make progress. He was a new graduate student, so some training in fundamental aspects of working with large datasets was necessary. What opportunities for training and professional development has the project provided?Students have been involved in the planning, preparation, and execution of Aims 1 and 2 and are now participating in Extension Aim 2. Moreover, this grant was the focus of a recently completed Ph.D. student's dissertation work. Students have also been encouraged to think beyond the scope of the proposed grant and consider the direction that the data are driving them. This has led to several new, unplanned research efforts and experiments. Students have also been involved in more routine training activities including data collection, analyses, and writing. Students have also made presentations at several conferences, which required preparing abstracts and posters for public consumption as well as preparing such that they are able to explain their data and impact to broad audiences. How have the results been disseminated to communities of interest?Over this reporting period we emphasized academic communication via publication and presentations to university colleagues. Given the progress of the grant, we anticipate that these activities will continue during the NCE year. Further, we expect to make additional presentations to lay audiences as the economic and applied analyses will be completed. What do you plan to do during the next reporting period to accomplish the goals?Research Aim 1. Determine the extent to which heat stress differentially causes phenotypic, systemic, metabolic, and muscle dysregulation in barrows and gilts. 1. Determine the extent to which sex impacts systemic dysfunction caused by heat stress. 2. Determine the extent to which sex impacts heat stress-mediated mitochondrial dysfunction. 3. Determine the extent to which sex impacts muscle dysfunction caused by heat stress. 4. Determine the extent to which sex regulates metabolic dysfunction caused by heat stress. Research Aim 1 is now complete. Our focus will be on preparation of publications in peer-reviewed journals as well as lay publications that summarize key aspects of our work. Research Aim 2. Determine the extent to which the effects of natural heat stress impact gilts and barrows in a production system. 1. In our approach we will analyze data sets collected at commercial swine farms. We will complete analyses of relevant production-level data. Extension Aim 1. Determine the differential economic and environmental impacts of lost growth efficiency caused by heat stress in gilts and barrows and transfer that knowledge to producer audiences in an effort to affect positive change in the pork industry. 1. In this aim we will leverage data supplied by producers as in Aim 2. A budgeting approach will be utilized to estimate the total cost of productivity (efficiency) losses due to HS for barrows and gilts separately for a representative swine farm. We will complete analyses of relevant production-level data. Extension Aim 2. Demonstrate effective engineered cooling strategies to the pork industry. 1. Current ventilation management strategies will be adapted to target heat stress mitigation for a particular sex. 2. We will demonstrate to producers and educate producers how to effectively use ventilation and cooling systems to mitigate the negative effects of HS. We will continue to work with the Extension team to develop materials and continue to update them with new knowledge as it becomes available. We are hopeful that this will include data focused on ventilation/barn conditions, the economics of heat stress, and the consequences of heat stress in barrows and gilts at the production level.
Impacts
What was accomplished under these goals?
Research Aim 1. Determine the extent to which heat stress differentially causes phenotypic, systemic, metabolic, and muscle dysregulation in barrows and gilts. 1. Determine the extent to which sex impacts systemic dysfunction caused by heat stress. 2. Determine the extent to which sex impacts heat stress-mediated mitochondrial dysfunction. 3. Determine the extent to which sex impacts muscle dysfunction caused by heat stress. 4. Determine the extent to which sex regulates metabolic dysfunction caused by heat stress. Objectives 1 and 2 were largely completed following year 2 of the award. Objectives 3 and 4 were largely completed during year 3 of the award. Collectively, this has resulted in three publications to date. In addition, at the time of this writing a paper containing mitochondrial function and a deep look at muscle and systemic metabolism is in review, though was beyond the range of year 4 so is omitted from the list above (submitted in Dec, 2024). We anticipate additional papers focused on proteostasis and amino acid utilization during the present no-cost extension year. The final piece of data needed for muscle and systemic metabolism work was completed during year 4. Here, Dr. Rhoads was able to measure metabolic flexibility in heat-stressed skeletal muscle from barrows and gilts. In brief, he discovered that males tended to be more metabolically flexible, regardless of treatment group. More interestingly, males were better able to maintain metabolic flexibility in the face of persistent heat stress than gilts. Ultimately, this means that mitochondrial health and function were better preserved in muscle from barrows than from gilts. These outcomes were consistent with our previous discoveries from high-resolution respirometry and support our previous metabolomics work. Looking forward, we may explore the diaphragm from these animals. This presents an interesting contrast to conventionally selected limb muscles, as during heat stress, animals become largely sedentary but pant. Hence, the limb muscle is hyperthermic but is largely not used, but the diaphragm is hyperthermic, and now its work rate has nearly tripled. How this muscle may respond to heat stress is unknown, but contrasting outcomes discovered in the diaphragm with those previously discovered in limb muscle may provide some mechanistic insight regarding heat stress-mediated dysfunction as well as the consequences of increased work during chronic hyperthermia. Research Aim 2. Determine the extent to which the effects of natural heat stress impact gilts and barrows in a production system. 1. In our approach we will analyze data sets collected at commercial swine farms. Data analysis is fully underway. We have raw data from more than 60,000 pigs from multiple facilities that are currently being analyzed. We also have internal barn environmental data as well as external environmental data. Extension Aim 1. Determine the differential economic and environmental impacts of lost growth efficiency caused by heat stress in gilts and barrows and transfer that knowledge to producer audiences in an effort to affect positive change in the pork industry. 1. In this aim we will leverage data supplied by producers as in Aim 2. A budgeting approach will be utilized to estimate the total cost of productivity (efficiency) losses due to HS for barrows and gilts separately for a representative swine farm. Here are the assumptions/parameters that we are including in the models. We are doing sensitivity analysis around these point estimates as well: Breeding herd impact Typically observe a reduction in annualized farrowing rate (the Steve Pollmann work found a reduction of 2.3%) and litter size (0.06) during summer matings (Apr to Aug). We are doing sensitivity around these assumed estimates. Matings done in the summer months will generally affect results for about five months starting in October to February. November and December results are generally the worst months due to matings done in June to August. The majority (94% of the total is what Pollmann found) of the financial impact is related to reduced farrowing rate with 6% of the impact related to litter size. We are doing sensitivity around these assumed estimates. Finishing pig impact The largest effects are due to reduced gain resulting in lighter carcass weights (8 to 10 lbs) and a slight increase in mortality (0.5 to 1.0%). The duration of the dip is generally 5 months with the lightest weights in July and August. Changes in mortality, feed efficiency, and daily gain or finish weight are the parameters that can vary in the model and sensitivity analysis shown. We allow for differences in barrows and gilts. We are providing the outputs similar to the Assessing Economic Opportunity of Improving Mortality Rate in Breed-to-Wean Swine Production and Assessing Economic Opportunity of Improving Mortality Rate in Wean-to-Finish Swine Production work, i.e., information file factsheets and decision tool spreadsheets. This will allow for further dissemination through presentations, popular press articles, etc. Extension Aim 2. Demonstrate effective engineered cooling strategies to the pork industry. 1. Current ventilation management strategies will be adapted to target heat stress mitigation for a particular sex. 2. We will demonstrate to producers and educate producers how to effectively use ventilation and cooling systems to mitigate the negative effects of HS. Because of our progress, our outputs tended to be more complete stories about various aspects of heat stress. We were invited to participate in the Swine Health Blackbelt Podcast as well as the IPIC seminar series. We also spoke at the Iowa chapter of the American Association of Laboratory Animal Scientists. Based on the strength of that presentation, we were invited to speak at the District 6 meeting. Here, we shared our discoveries with veterinarians and animal health technicians who care for animals in laboratory settings.
Publications
- Type:
Other Journal Articles
Status:
Published
Year Published:
2024
Citation:
Rudolph TE, Roths M, Freestone AD, Yap SQ, Michael A, White-Springer SH, Rhoads RP, Baumgard LH, and Selsby JT. Biological sex impacts oxidative stress in skeletal muscle in a porcine heat stress model. American Journal of Physiology Regulatory, Integrative and Comparative Physiology.
- Type:
Other Journal Articles
Status:
Published
Year Published:
2024
Citation:
Rudolph TE, Roths M, Freestone AD, White-Springer SH, Rhoads RP, Baumgard LH, and Selsby JT. Heat stress alters hematological parameters in barrows and gilts. Journal of Animal Science
- Type:
Other Journal Articles
Status:
Published
Year Published:
2024
Citation:
Rudolph TE, Roths M, Freestone AD, Rhoads RP, White-Springer SH, Baumgard LH, and Selsby JT. The contribution of biological sex to heat stress-mediated outcomes in growing pigs. Animal.
|
Progress 09/01/22 to 08/31/23
Outputs
Target Audience:Target audience includes producers, veterinarians, allied Industries, extension staff, and scientists. Changes/Problems:Finding and retaining suitable graduate students remains a challenge. While one graduate student was exceedingly successful leading these efforts, after her graduation in December, 2023, finding an heir-apparent has been a struggle. Also, stress continues to remain high. The culmination of these things, as well as continued limitations of staffing levels in some areas is a challenge for productivity. It is unclear if this is a transient problem, coincidental, or a more substantial societal shift prompted by COVID-19. Challenge - Engagement of the Extension team has been moderate. This remains an obstacle. IPIC leadership continues to be enthusiastic, but enthusiasm from Extension Agents is moderate. Again, discussion is good and in meetings enthusiasm is high, but translating those conversations to tangible Extension products continues to underwhelm. Solution - I will continue to work with the Extension team and continue to voice my enthusiasm for their work and efforts. I will also continue to seek ways, independent of the Extension team, to reach producers. Challenge - Aim 2 and Extension Aim 1 are moving slower than expected. ?I think we now have a reliable dataset to accomplish goals of both Aims noted above. Also, a student has been identified to lead Aim 2 analyses. This was somewhat slowed by the departure of the original faculty member and the arrival of a suitable replacement. Hopefully, this will go smoothly here forward. What opportunities for training and professional development has the project provided?Students have been involved in the planning, preparation, and execution of Aim 1 and are now participating in Extension Aim 2. Students have also been encouraged to think beyond the scope of the proposed grant and consider the direction that the data are driving them. This has led to several new, unplanned research efforts and experiments. Students have also been involved in more routine training activities including data collection, analyses, and writing. Students have also made presentations at several conferences, which required preparing abstracts and posters for public consumption as well as preparing such that they are able to explain their data and impact to broad audiences. How have the results been disseminated to communities of interest?Over this reporting period we have done a good job disseminating information to our target audiences. Indeed, multiple presentations were given to producers/allied industries, to veterinarians and staff charged directly with animal care, and to scientists. Given the progress of the grant, we expect that such productivity will continue in the coming reporting period. What do you plan to do during the next reporting period to accomplish the goals?Research Aim 1. Determine the extent to which heat stress differentially causes phenotypic, systemic, metabolic, and muscle dysregulation in barrows and gilts. 1. Determine the extent to which sex impacts systemic dysfunction caused by heat stress. 2. Determine the extent to which sex impacts heat stress-mediated mitochondrial dysfunction. 3. Determine the extent to which sex impacts muscle dysfunction caused by heat stress. 4. Determine the extent to which sex regulates metabolic dysfunction caused by heat stress. Objective 1 is largely complete. We are becoming more convinced that the metabolism and nutrient mobilization and utilization of heat stress animals is more complex than previously thought and would be best addressed through tracer studies where we can follow nutrients throughout a heating period. We are also considering a metabolomics experiment focused on the digesta from each animal. Given the potential for differential gut storage and intestinal damage, it seems likely that absorption may differ between TN and HS animals. We are working through the logistics to assure that such an approach is logically sound and will address the hypothesis we are interested in testing. Experiments proposed in objective 2 are complete. Additional experiments that expand observations made in objective 2 may be performed as needed. For example, we may explore metabolic flexibility in muscle from these animals. In the next reporting period we expect to push further into objectives 3 and 4 where we will provide much more biochemical detail regarding the impacts of heat stress. As an example, we are exploring proteostasis as it appears that proteolysis is not increased; however, protein synthesis is decreased. Research Aim 2. Determine the extent to which the effects of natural heat stress impact gilts and barrows in a production system. 1. In our approach we will analyze data sets collected at commercial swine farms. Given raw data in-hand, we expect that over the next reporting period, we will be able to address our proposed hypotheses. Further, since we have internal and external environmental data, we are interested in better appreciating how the two are related to each other and then ultimately to changes in pig production metrics. We are considering if the data at present support such an analysis. Extension Aim 1. Determine the differential economic and environmental impacts of lost growth efficiency caused by heat stress in gilts and barrows and transfer that knowledge to producer audiences in an effort to affect positive change in the pork industry 1. In this aim we will leverage data supplied by producers as in Aim 2. A budgeting approach will be utilized to estimate the total cost of productivity (efficiency) losses due to HS for barrows and gilts separately for a representative swine farm. We expect to complete this project objective during this reporting period using data in-hand. Extension Aim 2. Demonstrate effective engineered cooling strategies to the pork industry. 1. Current ventilation management strategies will be adapted to target heat stress mitigation for a particular sex. 2. We will demonstrate to producers and educate producers how to effectively use ventilation and cooling systems to mitigate the negative effects of HS. Despite our success in this reporting period, the execution of this phase of the grant has been slower than expected (discussed in more detail below). In the next reporting period, we will continue to work with the Extension team to develop materials and continue to update them with new knowledge as it becomes available. In addition, over the next reporting period we expect to: Participate in the traveling Extension tour. Publish a lay article in a relevant publication. Make presentations to scientific audiences. For example, Dr. Selsby has already spoken at Rutgers University and will present at the University of Florida in the coming months. Give a presentation at the AALAS regional conference.
Impacts
What was accomplished under these goals?
Research Aim 1. Determine the extent to which heat stress differentially causes phenotypic, systemic, metabolic, and muscle dysregulation in barrows and gilts. 1. Determine the extent to which sex impacts systemic dysfunction caused by heat stress. 2. Determine the extent to which sex impacts heat stress-mediated mitochondrial dysfunction. 3. Determine the extent to which sex impacts muscle dysfunction caused by heat stress. 4. Determine the extent to which sex regulates metabolic dysfunction caused by heat stress. In this reporting period, as objectives 1 and 2 are largely complete, we emphasized heat stress-mediated changes in skeletal muscle taken from barrows and gilts focused on objectives 3 and 4. Indeed, papers that include production metrics and changes in hematological parameters are in review. A paper containing our measures of mitochondrial function is circulating amongst co-authors and will be submitted in early 2024. In this reporting period, and consistent with our hypothesis, we discovered that muscle from barrows was more resistant to oxidative stress than muscle from gilts. These data are also in review. An observation that continues to puzzle us is the mechanism underlying maintenance of blood glucose during a persistent heating event, as in our 7 d animals. Not only are animals hot, but they are eating less than control animals. Convention holds that heat stress prevents mobilization of fatty acids, which our data corroborate, leaving glycogen and protein as potential substrates. While whole-body insulin sensitivity increases, muscle insulin sensitivity decreases, as does signaling needed to support oxidative phosphorylation, which further implicates protein. Note, increased proteolysis would also explain decreased growth caused by heat stress. We discovered that circulating amino acids plummet during heating in both barrows and gilts. Remarkably, skeletal muscle amino acids were only slightly decreased. Consistent with this, markers of skeletal muscle proteolysis, including calpain and proteasome activities, are largely unaffected, which is counter to accepted dogma. Markers of protein synthesis suggest strongly that synthesis is impaired by heat stress. When we did a deeper dive into changes in muscle amino acids we discovered that, while on the whole, amino acids were largely held by skeletal muscle, ketogenic amino acids were decreased by approximately 50%, which may indicate increased reliance on ketones as a source of ATP. Papers containing these data are in preparation and will be submitted toward the middle and end of 2024. We are eager to pursue this hypothesis and this further underscores the urgent need to perform tracer studies as noted in last year's report. Another potential explanation for the preservation of blood glucose is in regard to energy balance and plane of nutrition. Clearly, heat stressed animals eat less than their TN counterparts. Heat stressed animals; however, may be able to minimize the energy requirement needed for thermogenesis as this function is now supported by the hot environmental conditions. In such a case, not only are these calories not needed, the induced sedentary condition may also decrease the need for calories necessary to support basal functions and even growth. Some support for this idea comes from the feed consumption and feed efficiency data. While feed consumption remains low throughout the heating period, growth efficiency (feed:gain) returns to normal following 7 d of HS. To test this hypothesis, we envision feeding a diet enriched for amino acids in order to meet the amino acid requirement in the face of decreased feed consumption, though are aware of our previous data indicating digesta are trapped in the stomach and passage rate through the small intestine may be increased. Research Aim 2. Determine the extent to which the effects of natural heat stress impact gilts and barrows in a production system. 1. In our approach we will analyze data sets collected at commercial swine farms. Data analysis is fully underway. We have raw data from more than 60,000 pigs from multiple facilities that are currently being analyzed. We also have internal barn environmental data as well as external environmental data. Extension Aim 1. Determine the differential economic and environmental impacts of lost growth efficiency caused by heat stress in gilts and barrows and transfer that knowledge to producer audiences in an effort to affect positive change in the pork industry. 1. In this aim we will leverage data supplied by producers as in Aim 2. A budgeting approach will be utilized to estimate the total cost of productivity (efficiency) losses due to HS for barrows and gilts separately for a representative swine farm. We have not yet initiated Extension Aim 1. Extension Aim 2. Demonstrate effective engineered cooling strategies to the pork industry. 1. Current ventilation management strategies will be adapted to target heat stress mitigation for a particular sex. 2. We will demonstrate to producers and educate producers how to effectively use ventilation and cooling systems to mitigate the negative effects of HS. The research team continues to engage with the Extension team. Again, we met in several sessions over the previous year to keep the Extension team abreast of our progress and share new knowledge. We also emphasized dissemination of our data to a variety of audiences. For example, we published a popular press article in Iowa Pork Producers Association Magazine and also supported a series of Swine X podcasts targeting producers and industry professionals. We were also invited to appear on the Swine It podcast. In addition to these activities, we made presentations at the Iowa Pork Congress, where students were awarded 2nd and 3rd place awards for their presentations, and a presentation at Iowa Swine Day. Finally, we joined an Extension traveling workshop that went throughout the state of Iowa and discussed ventilation controls. This workshop covered the state in a single week, with stops in the four corners of Iowa to better reach producers. We also accepted invitations to present data for graduate students at ISU in a seminar class. Further, we reached scientists by sharing data at the MWASAS conference and the Iowa Physiological Society conference. Data supported by this project were also contained within an invited talk associated with the Growth and Development Award from ASAS, which was awarded during this granting period. Finally, we reached veterinary staff and animal care staff. Internally, we were invited to give a presentation to the Laboratory Animal Resources group at ISU. Based on the success of that presentation, we were invited to share data with the Iowa chapter of the Association of Laboratory Animal Scientists and were recently invited to speak at the regional event in summer, 2024. We also connected with the Health Assurance group within PIC. This relationship led to an invited presentation in early 2023. Because of the success of that presentation and the reference to additional data, we were invited back to further discuss the impacts of heat stress.
Publications
- Type:
Journal Articles
Status:
Under Review
Year Published:
2024
Citation:
Rudolph TE, Roths M, Freestone AD, Yap SQ, Michael A, White-Springer SH, Rhoads RP, Baumgard LH, and Selsby JT. Biological sex impacts oxidative stress in skeletal muscle in a porcine heat stress model. American Journal of Physiology Regulatory, Integrative and Comparative Physiology, in review
- Type:
Journal Articles
Status:
Under Review
Year Published:
2024
Citation:
Rudolph TE, Roths M, Freestone AD, White-Springer SH, Rhoads RP, Baumgard LH, and Selsby JT. The contribution of biological sex to heat stress-mediated outcomes in growing pigs. Animal, in review
- Type:
Journal Articles
Status:
Under Review
Year Published:
2024
Citation:
Rudolph TE, Roths M, Freestone AD, White-Springer SH, Rhoads RP, Baumgard LH, and Selsby JT. Heat stress alters hematological parameters in barrows and gilts. Journal of Animal Science: in review.
- Type:
Other
Status:
Published
Year Published:
2023
Citation:
Selsby JT and Baumgard LH. An aha moment in heat stress research. Iowa Pork Producers Association Magazine.
- Type:
Conference Papers and Presentations
Status:
Other
Year Published:
2022
Citation:
Selsby, JT. NC1184 Iowa Station Report. University of Wisconsin. 9/29/22
- Type:
Conference Papers and Presentations
Status:
Other
Year Published:
2022
Citation:
Rudolph TE, Roths M, Freestone AD, Rhoads RP, Baumgard LH, and Selsby JT. The impact of biological sex on skeletal muscle metabolism following heat stress. Iowa Physiological Society, Iowa City, November, 2022.
- Type:
Conference Papers and Presentations
Status:
Other
Year Published:
2022
Citation:
A sex effect of heat stress. Genetics 691 11/7/22
- Type:
Conference Papers and Presentations
Status:
Other
Year Published:
2022
Citation:
A sex effect of heat stress. Lab Animal Resources seminar 11/10/22
- Type:
Conference Papers and Presentations
Status:
Other
Year Published:
2023
Citation:
Some like it hot!!! The impact of biological sex on heat stress-mediated outcomes. PIC Veterinary Heath Assurance Rounds. Virtual. 1/4/23
- Type:
Conference Papers and Presentations
Status:
Other
Year Published:
2023
Citation:
Achy Breaky Heart: The impact of environment-induced heat stress on the myocardium. PIC Veterinary Health Assurance Rounds. Virtual. 3/1/23
- Type:
Conference Papers and Presentations
Status:
Other
Year Published:
2023
Citation:
Some like it hot!!! The impact of biological sex on heat stress-mediated outcomes. Iowa Swine Day. Ames, IA, June, 2023
- Type:
Conference Papers and Presentations
Status:
Other
Year Published:
2023
Citation:
Some like it hot!!! The impact of biological sex on heat stress-mediated outcomes. Growth and Development Award Talk, American Society of Animal Scientists, Albuquerque, NM, July, 2023
- Type:
Conference Papers and Presentations
Status:
Other
Year Published:
2023
Citation:
Some like it hot!!! The impact of biological sex on heat stress-mediated outcomes. American Association of Laboratory Animal Scientists, Iowa Chapter. Ft. Dodge, IA, 9/21/23
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2023
Citation:
Rudolph TE, Roths M, Freestone AD, Rhoads RP, Baumgard LH. and Selsby JT. Sex-specific alterations in mitochondrial dynamics following environment-induced heat stress. Advances in Skeletal Muscle Biology in Health and Disease. Gainesville, FL, March 14-17th, 2023
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2023
Citation:
Roths M, Rudolph TE, Freestone AD, Baumgard LH, Selsby JT. Heat stress alters cardiac architecture and causes cellular dysfunction. IPIC/Iowa Pork Congress, Des Moines, IA, January 25-26, 2023
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2023
Citation:
Rudolph TE, Roths M, Freestone AD, Rhoads RP, Baumgard LH. and Selsby JT. The contribution of biological sex to heat stress-mediated production outcomes in growing pigs. IPIC/Iowa Pork Congress, Des Moines, IA, January 25-26, 2023
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2023
Citation:
Freestone AD, Rudolph TE, Roths M, Mayorga EJ, Abeyta MA, Goetz BM, Rodriguez-Jimenez S, Opgenorth J, Selsby JT, and Baumgard LH. Effects of mitoquinol during an acute heat stress in growing gilts. MWASAS, Madison, WI, March, 2023
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2022
Citation:
Rudolph TE, Roths M, Freestone AD, Rhoads RP, Baumgard LH, and Selsby JT. The impact of biological sex on skeletal muscle metabolism following heat stress. Iowa Physiological Society, Iowa City, November, 2022
|
Progress 09/01/21 to 08/31/22
Outputs
Target Audience:Producers Veterinarians Allied Industries Extension Staff Scientists Changes/Problems:It's become clear that problems created by COVID-19 will reverberate through the rest of the granting period and create delays. Stress levels continue to remain high, which may be a hangover from COVID, and appear to be further complicated by poor staffing levels at ISU and industry partners with whom we would like to collaborate. Challenge - Engagement of the Extension team has been moderate The IPIC leadership has changed and a new director was recently appointed. Remarkably, this has not changed the enthusiasm for IPIC leadership for a role in this project. Nevertheless, engagement with Extension agents appears moderate. In several meetings, enthusiasm appears high, discussion is rich and insightful, and steps to reach stakeholders are considered; however, it is unclear how this is translating to deliverables reaching stakeholders. Solution - I will continue to work with the Extension team and continue to voice my enthusiasm for their work and efforts. Also, I am taking on additional roles and responsibilities as noted by the expanded list and audiences of planned talks and activities. Challenge - Aim 2 and both extension aims have has also been delayed as research personnel here and at collaborating farms have been heavily taxed. We have made contact and had good engagement with several large producers, but follow through has been poor. Solution - As stress levels decline we expect data collection and our Extension program to resume over the next year. Further, we will dedicate a student to analysis of production data in support of Aim 2 and Extension objectives. What opportunities for training and professional development has the project provided?Students have been involved in the planning, preparation, and execution of Aim 1. As noted previously, COVID-related delays presented a unique training opportunity as we worked to overcome a host of logistical challenges. They also were part of decision making as we altered our scope to advance our knowledge about heat stress in light of these challenges. They were also involved in decision making and study design as we considered recovery. While certainly not part of a formal training program for students, it is these sorts of skills and experiences that will help them in their independent careers as, unfortunately, as we all know, research rarely goes as planned or anticipated. Something will go wrong. Something won't work. Hypotheses won't be supported. How we deal with those challenges will make huge impacts on productivity. Students have also been involved in more routine training activities including data collection, analyses, and writing. Students have also made presentations at several conferences, which required preparing abstracts and posters for public consumption as well as preparing such that they are able to explain their data and impact to broad audiences. How have the results been disseminated to communities of interest?Most of our efforts have been through academic channels. More specifically, we presented data in the form of abstracts at Experimental Biology and at the Midwest American Society of Animal Science conferences. Data were also presented to scientific colleagues at the annual meeting of USDA-focused muscle biologists as well as through a seminar to the Meat Science group at Iowa State University. Finally, we discussed our heat stress work in a lay publication as a deliberate effort to reach a broader audience. What do you plan to do during the next reporting period to accomplish the goals?Research Aim 1. Determine the extent to which heat stress differentially causes phenotypic, systemic, metabolic, and muscle dysregulation in barrows and gilts. 1. Determine the extent to which sex impacts systemic dysfunction caused by heat stress. 2. Determine the extent to which sex impacts heat stress-mediated mitochondrial dysfunction. 3. Determine the extent to which sex impacts muscle dysfunction caused by heat stress. 4. Determine the extent to which sex regulates metabolic dysfunction caused by heat stress. As predicted in last year's report, we have completed planned experiments in objective 1 and are expanding beyond what we proposed. In addition, given our findings of alterations in digestive function caused by heat stress, future studies aimed at better appreciated alterations in nutrient localization during heat stress are being considered. In these experiments we are picturing tracers in feed to monitor passage rates and deep analyses of nutrients contained within the digesta. Experiments proposed in objective 2 are complete. Additional experiments that expand observations made in objective 2 may be performed as needed. In the next reporting period we expect to continue and refine these measures as well as push further into objectives 3 and 4 where we will provide much more biochemical detail regarding the impacts of heat stress. Research Aim 2. Determine the extent to which the effects of natural heat stress impact gilts and barrows in a production system. 1. In our approach we will analyze data sets collected at commercial swine farms. We expect that data collection will continue during this reporting period and are hopeful sufficient data will be available to support objective analyses. Extension Aim 1. Determine the differential economic and environmental impacts of lost growth efficiency caused by heat stress in gilts and barrows and transfer that knowledge to producer audiences in an effort to affect positive change in the pork industry. 1. In this aim we will leverage data supplied by producers as in Aim 2. A budgeting approach will be utilized to estimate the total cost of productivity (efficiency) losses due to HS for barrows and gilts separately for a representative swine farm. We expect that data collection will continue during this reporting period and are hopeful sufficient data will be available to support objective analyses. Extension Aim 2. Demonstrate effective engineered cooling strategies to the pork industry. 1. Current ventilation management strategies will be adapted to target heat stress mitigation for a particular sex. 2. We will demonstrate to producers and educate producers how to effectively use ventilation and cooling systems to mitigate the negative effects of HS. Execution of this phase of the grant has been slower than expected (discussed in more detail below). Nevertheless, we are planning to move forward here as the grant has produced more data. Further, we have already, at the time of this writing, planned or executed the following that will contribute to next year's accomplishments: We planned a podcast series. Recording with key members of the research team have already been scheduled and the preamble has already been recorded. We have drafted an article intended to reach producers to be published in Iowa Pork Producers Association Magazine that offers a high-level update of our research activities and key finding. We will discuss ventilation for heat stress conditions in the annual Extension show that visits all four corners of Iowa in a single week Two students presented data at Iowa Pork Congress. These students earned 2nd and 3rd place awards for their efforts. Dr. Selsby has accepted a speaking spot at the coming Iowa Swine Day Presentations about this work has been given to academic colleagues at other universities, to the Laboratory Animal Resource team at ISU, and to the Animal Health team at PIC The PIC veterinary group may have us back to discuss our findings in hearts in more detail
Impacts
What was accomplished under these goals?
Research Aim 1. Determine the extent to which heat stress differentially causes phenotypic, systemic, metabolic, and muscle dysregulation in barrows and gilts. 1. Determine the extent to which sex impacts systemic dysfunction caused by heat stress. 2. Determine the extent to which sex impacts heat stress-mediated mitochondrial dysfunction. 3. Determine the extent to which sex impacts muscle dysfunction caused by heat stress. 4. Determine the extent to which sex regulates metabolic dysfunction caused by heat stress. As planned in the year 1 progress report, we completed the in vivo phase of this experiment in Fall '21. We successfully heated all needed barrows and gilts for one or seven days and collected needed phenotypic and production data as well as needed blood and muscle for future experiments. At present, several manuscripts containing these data are nearing submission including one focused on production-level metrics, one focused on blood variables including changes in circulating nutrients and endocrine signals, and one focused on muscle metabolism during heat stress. While each of these datasets provides insight into the role of biological sex on heat stress-mediated outcomes, as intended, it is the synthesis of this information, across experiments, that provides real impact. For example, through synthesizing these data, we have discovered that during the initial periods of heat stress, barrows and gilts reach a similar, elevated core temperature. As heating continues, gilts are able to decrease temperature, whereas barrows are not. When production variables are considered it is apparent that gilts are more severely impacted during the first day of heating when temperatures are similar and during 7 d of heat stress when gilts are cooler, production metrics are similar between groups. These data suggesting heat resistance in barrows are supported by changes in the metabolome, mitochondrial function, and in mitochondrial structure that also support improved efficiency in barrows compared to gilts. Separately, we expanded our planned measures and did a deeper dive than expected focused on gut fill. Data from a previous experiment suggested this could be altered by heat stress. In confirmation of that earlier work, we found that during heat stress a large portion of consumed food is trapped in the stomach at the expense of the small intestine. This may be a protective mechanism to keep nutrients away from the fauna and flora living in gut and chronic stomach distension may contribute to decreased feed intake. While seemingly a footnote of heat stress physiology, the practical implications may be substantial. That is, food trapped in the stomach is not available for further digestion or absorption as this occurs in the small intestine. Further, it has already been established that the small intestine is damaged during heat stress and the absorptive machinery may not be functioning optimally. The summation of this evidence points to limited impact of nutritional interventions during heat stress because such therapeutics are trapped in the wrong compartment. We will continue to debate the further impacts of these outcomes. Research Aim 2. Determine the extent to which the effects of natural heat stress impact gilts and barrows in a production system. 1. In our approach we will analyze data sets collected at commercial swine farms. Data collection is continuing as we seek additional industry partners willing to share commercial data. Extension Aim 1. Determine the differential economic and environmental impacts of lost growth efficiency caused by heat stress in gilts and barrows and transfer that knowledge to producer audiences in an effort to affect positive change in the pork industry. 1. In this aim we will leverage data supplied by producers as in Aim 2. A budgeting approach will be utilized to estimate the total cost of productivity (efficiency) losses due to HS for barrows and gilts separately for a representative swine farm. We have not yet initiated Extension Aim 1. Extension Aim 2. Demonstrate effective engineered cooling strategies to the pork industry. 1. Current ventilation management strategies will be adapted to target heat stress mitigation for a particular sex. 2. We will demonstrate to producers and educate producers how to effectively use ventilation and cooling systems to mitigate the negative effects of HS. The research team has engaged several times with the Extension team. These sessions served two purposes. The first was to educate the Extension staff so that they are better informed and can help disseminate and translate our research discoveries to or stakeholders. The second purpose was to plan future Extension activities that might allow greater interaction amongst the research group, the Extension group, and our stakeholders. These sessions have been fruitful and set the stage nicely for continued execution over the coming year. These meetings also resulted in a lay publication led by the Extension team. We also added a demonstration project that was not part of the planned proposal. We had a unique opportunity to follow pigs during the recovery from heat stress so tracked them through market weight. This project provided: 1) a good training opportunity for students, 2) preliminary data and a convincing rationale that this project should be repeated in a more in-depth, intensive way, and 3) we hope data that could be useful to stakeholders. Analyses are continuing.
Publications
- Type:
Other
Status:
Published
Year Published:
2021
Citation:
Romoser M., Selsby J, and Ramirez B. Heat stress and minimizing the impact. National Hog Farmer. June, 2022.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2021
Citation:
Selsby, JT. NC1184 Iowa Station Report. University of Georgia. 10/30/2021.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2022
Citation:
Feelin Hot Hot Hot: Heat stress-mediated changes in skeletal muscle. Meat Science Seminar, Iowa State; 2/8/2022.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2022
Citation:
Rudolph TE, Harold K, Opgenorth J, Baumgard LH, and Selsby JT. Defining the role of endotoxemia during heat stress in oxidative skeletal muscle. Experimental Biology, Philadelphia, April, 2022.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2022
Citation:
Roths M, Rudolph TE, Freestone A, Baumgard LH, and Selsby JT. Heat stress-induced changes in the myocardium. Experimental Biology, Philadelphia, April, 2022.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2022
Citation:
Wesolowski LT, Semanchik PL, Simons JL, Rudolph ET, Roths M, Selsby JT, and Spring-White SH. Heat stress increases mitochondrial complex I capacity in female pigs but favors reliance on complex II in males. Experimental Biology, Philadelphia, April, 2022.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2022
Citation:
Semanchik P, Wesolowski LT, Simons SJ, Freestone A, Rudolph TE, Roths M, Rhoads RP, Baumgard LH, Selsby JT, and White-Springer SH. Heat stress more negatively impacts cardiac muscle mitochondria in female versus male pigs. Experimental Biology, Philadelphia, April, 2022.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2022
Citation:
Roths M, Rudolph T, Freestone A, Baumgard LH, and Selsby JT. Heat stress causes persistent multisystem dysfunction. MWASAS. Omaha, NE, March, 2022.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2022
Citation:
Rudolph TE, Roach CM, Baumgard LH, Keating AF, and Selsby JT. The interaction between heat stress and zearalenone toxicity in porcine skeletal muscle. MWASAS. Omaha, NE, March 2022.
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Progress 09/01/20 to 08/31/21
Outputs
Target Audience: Producers Veterinarians Allied Industries Extension Staff Scientists Changes/Problems:Problem - COVID-19 impacted this project in several ways, all of which contributed to delay our intended start. This was manifested through difficulty in identifying and recruiting suitable students, delays in other projects, which created staffing issues and barn availability challenges, and the increased stress navigating in a COVID-environment. We had hoped to complete the in vivo phase of the project in the spring of 2021 but had to push the in vivo phase to the fall of 2021, which was just beyond the close of the reporting period. Solution - We completed the in vivo phase of the project in the fall of 2021, which was approximately 6 mo later than we had intended. Notably, the experiment appeared to be well-performed and executed, needed tissues were collected and distributed, and measures necessitating fresh tissues were performed. It is unclear if this delay will require a NCE at the conclusion of the granting period. Problem - Aim 2 and both extension aims have has also been delayed as research personnel here and at collaborating farms have been heavily taxed. Solution - As stress levels decline we expect data collection and our Extension program to resume over the next year. Change 1 - Recovery Experiment 1 As part of a closed NIFA-funded project we heat stressed an additional 12 pigs to be used as extras should one of the enrolled pigs be disqualified (illness, death). As part of those preparations we collected blood before and after HS, but then returned the pigs to the herd for finishing. We decided to collect blood from these pigs just before they went to slaughter, some 3 mo following HS. Given some data regarding heart health (see below) we performed a blood panel with a focus on heart/muscle, renal, and hepatic injury. Remarkably, we have clear evidence of muscle and heart injury following heat stress, which after careful scrutiny of published data, are amongst the first record of these findings. We also discovered markers of renal and hepatic injury. Further, and excitingly, of these 12 pigs, 8 were barrows and 4 were gilts. When sex was considered we discovered that biological sex was a significant factor for several outcomes. Finally, some of these changes were also detected three months following a single HS bout. These data will be presented at the coming MWASAS meeting and a manuscript containing these data is in preparation. Change 2 - Recovery Experiment 2 Given the exciting results from the first recovery experiment and the potential for an impact of biological sex on HS-mediated outcomes we decided to repeat this experiment. We considered using outcomes from Recovery Experiment 1 as preliminary data to support a new NIFA application, but decided that these data could be informative to the swine industry and therefore, there was sufficient justification to move with urgency. In brief, 16 gilts and barrows were held under TN conditions and then half of each sex was subjected to 3 d of HS. Blood was collected before, during, and after HS. Pigs will be followed until marketing, which we anticipate will come at the end of January. We have been collecting detailed, individual production measures and blood throughout the recovery process. We are eager to discover the extent to which biological sex impacts recovery from HS. These data will directly support the Extension mission of our proposal. In addition, given outcomes from Recovery Experiment 1, we are eager to explore the potential for lasting cardiac, renal, and hepatic injury. These data may open new possibilities for therapeutic intervention if we confirm injury to other organ systems. Heat stress-mediated cardiac injury A technician/graduate student was interested in how heat stress might damage the myocardium. We discussed several approaches to assess this is she had the creative idea to use calipers to measure heart dimensions. Shockingly, she discovered changes in left ventricle and right ventricle wall thicknesses as well as a shortening of the external cardiac dimension (apex to base). She is in the process of a biochemical evaluation of LV and RV following 24 h of HS. We were able to support this project largely using left over tissues and supplies from other projects so the risk was low and the reward was quite high. These outcomes and that of our recovery experiments is forcing us to consider the heat stressed pig, and pigs in general, more holistically. We are having early discussions about whole-pig health and its potential importance for production efficiency with and without (heat, disease, water, nutrient, social, etc.) stress. What opportunities for training and professional development has the project provided?Students have been involved in the planning and preparation for Aim 1 from the onset. This has created an interesting environment as COVID has created some additional logistical challenges that ultimately let to the postponement of our initially planned project. Students were part of our discussions as we weighed pros and cons of moving forward vs postponing. Ultimately, we decided that postponing was in the best interest of the project and the people involved in it. Student involvement was intentional and intended to help grow their decision making when faced with multiple, competing priorities combined with high pressure and high demands. Separately, the postponement of this project created opportunities to explore some questions that we might not have otherwise considered. This necessitated consideration of systems beyond those which we typically investigate including the kidneys, heart, and liver. These projects are discussed in the Changes section. How have the results been disseminated to communities of interest?No progress What do you plan to do during the next reporting period to accomplish the goals?Over the next year we will complete the in vivo phase of the project described in Aim 1. Indeed, at the time of this writing this has already been completed. We are in the process of processing production and vital parameter data collected during the acclimation phase, the pre-heating phase, and during the heating phase. As an early outcome it appears that even though they were in the same room at the same time as gilts, and pigs of both sexes were evenly distributed throughout the room, barrows had a slightly higher core temperature during heating. This was also reflected in muscle temperature at the time of collection. Research Aim 1. Determine the extent to which heat stress differentially causes phenotypic, systemic, metabolic, and muscle dysregulation in barrows and gilts. 1. Determine the extent to which sex impacts systemic dysfunction caused by heat stress. 2. Determine the extent to which sex impacts heat stress-mediated mitochondrial dysfunction. 3. Determine the extent to which sex impacts muscle dysfunction caused by heat stress. 4. Determine the extent to which sex regulates metabolic dysfunction caused by heat stress. For objective 1, we anticipate we will have completed planned analyses and likely expanded beyond measures proposed in our grant. For example, early outcomes from a previous experiment indicated differences in gut fill in different parts of the GI tract. That is, food was eaten but was trapped in the stomach during HS, meaning it is not available for nutrient extraction (or metabolic heat production). We are hopeful this outcome will be repeated in the study herein and are interested to determine the extent to which this is altered by sex. Mitochondrial functional measures have already been completed in support of objective 2. We are planning additional measures of mitochondrial injury as well as metabolomics over the course the next reporting period. We have also been in contact with the microscopy core for EM of collected muscle. Over the next reporting period we expect to make progress assessing signaling changes in muscle. Indeed, muscle has already been extracted and we are planning to assess redox balance in coming months. We will also likely probe SERCA dysregulation in the next reporting period. To support objective 4, Dr. Rhoads was sent serum from gilts and barrows used for the in vivo phase of the investigation. He was also sent whole muscle to support satellite cell isolation. We are hopeful that he will begin experiments focused on in vitro measures of metabolic function in cells from HS barrows and gilts, but also from cells bathed in serum from TN/HS barrow or gilts. Research Aim 2. Determine the extent to which the effects of natural heat stress impact gilts and barrows in a production system. 1. In our approach we will analyze data sets collected at commercial swine farms. We expect that data collection will continue during this reporting period and are hopeful sufficient data will be available to support objective analyses. Extension Aim 1. Determine the differential economic and environmental impacts of lost growth efficiency caused by heat stress in gilts and barrows and transfer that knowledge to producer audiences in an effort to affect positive change in the pork industry. 1. In this aim we will leverage data supplied by producers as in Aim 2. A budgeting approach will be utilized to estimate the total cost of productivity (efficiency) losses due to HS for barrows and gilts separately for a representative swine farm. We expect that data collection will continue during this reporting period and are hopeful sufficient data will be available to support objective analyses. Extension Aim 2. Demonstrate effective engineered cooling strategies to the pork industry. 1. Current ventilation management strategies will be adapted to target heat stress mitigation for a particular sex. 2. We will demonstrate to producers and educate producers how to effectively use ventilation and cooling systems to mitigate the negative effects of HS. In this objective, we expect that we will begin to prepare Extension material for broad distribution. To support this, the IPIC team has already met and is beginning to execute their plan. This will include traditional printed material but also digital content all supported on dedicated pages on the IPIC website. We also expect that planning for an on-farm experiment will begin where different ventilation conditions are employed in several environmental conditions.
Impacts
What was accomplished under these goals?
Research Aim 1. Determine the extent to which heat stress differentially causes phenotypic, systemic, metabolic, and muscle dysregulation in barrows and gilts. 1. Determine the extent to which sex impacts systemic dysfunction caused by heat stress. 2. Determine the extent to which sex impacts heat stress-mediated mitochondrial dysfunction. 3. Determine the extent to which sex impacts muscle dysfunction caused by heat stress. 4. Determine the extent to which sex regulates metabolic dysfunction caused by heat stress. COVID has had some unexpected impacts on our research progress and certainly contributed to delays for this objective. We hoped to complete the in vivo phase of this project during the first year of the project, but that was not possible. We planned the in vivo phase of the project for execution in the fall, which falls beyond this reporting period. Please see the future plans section for details. Research Aim 2. Determine the extent to which the effects of natural heat stress impact gilts and barrows in a production system. 1. In our approach we will analyze data sets collected at commercial swine farms. Data collection was started for this research objective and will continue into the coming project year. Extension Aim 1. Determine the differential economic and environmental impacts of lost growth efficiency caused by heat stress in gilts and barrows and transfer that knowledge to producer audiences in an effort to affect positive change in the pork industry. 1. In this aim we will leverage data supplied by producers as in Aim 2. A budgeting approach will be utilized to estimate the total cost of productivity (efficiency) losses due to HS for barrows and gilts separately for a representative swine farm. We have not initiated Extension Aim 1. Extension Aim 2. Demonstrate effective engineered cooling strategies to the pork industry. 1. Current ventilation management strategies will be adapted to target heat stress mitigation for a particular sex. 2. We will demonstrate to producers and educate producers how to effectively use ventilation and cooling systems to mitigate the negative effects of HS. We have not yet initiated Extension Aim 2.
Publications
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