bluuebunny/crossref_metadata_2025 huggingface dataset:
542 Rethinking/reexamining Grand Challenges Within Teaching for Workforce Readiness – a Scorecard and Recalibration
Authors: Mulvaney Donald R , Rosenkrans Charles F
Published: October 2021

The ASAS Public Policy Committee (PPC) provides updates of Grand Challenges (GCs; www.asas.org/about/public-policy/asas-grand-challenges) which clearly articulate research priorities while providing science-based information for shaping public policy, and to enhance future funding for research and education programs in animal sciences (AS). In this nexus symposium for 2021, PPC examines previous stated priorities and provides a progress report card and offers additional perspectives and recommendations for research needed to address some of the GCs continuing to face animal agriculture. Among the GCs is teaching for workforce readiness (WR) as the preparation of graduates for diverse roles in the modern workforce has provoked substantial research in recent years. Ensuring new and returning workplace entrants are prepared to enter the workforce with requisite knowledge, skills, abilities, and experiential attributes required in a diverse array of occupations is a GC. Through an examination of the past, present and future instructional landscape, we will examine a gap which exists between WR and expectations of future employers. Expected employee competencies will include critical thinking and problem solving, mastery of human relationship skills and leadership mindsets, diverse and effective communication abilities, influence skills and workplace emotional intelligence. Instructive to meeting the GC are principles identified in ASAS Accreditation Standards for Animal Science Programs. Those standards strive to ensure graduates can communicate the importance of animal agriculture and STEM biology to an increasingly non-ag world. Among the GC of providing experiences are increased emphasis on high-impact programming around internships, externships and apprenticeships layered onto a knowledge, scaffolded curriculum. Use of research methodology to develop and incorporate into practice varied instructional modalities, technologies and practices within a dynamic higher education landscape requires intentional, systematic, and iterative scholarly approaches; which will enable creation of adaptive learning experiences and learning outcomes needed for an ever-changing workplace with its unique challenges and opportunities.
139 Disinformation and Scientific Integrity: The Bad Stuff Is Easier to Believe
Authors: Ryan Camille D
Published: October 2021

The sensational nature of disinformation attracts millions of readers and attention is a scarce resource. And because it attracts the masses, it can be used to undermine or target science and – ultimately – used for monetary gain. How this is done, in practice, is less understood. This presentation provides insights into how we can better understand how this is done through data analysis. We utilize a dataset of ~95,000 unique online articles to evaluate and explore the various tactics that contribute to the evolving disinformation narratives. We are interested in both the who and the how of (dis)information; what incentivizes it and the behavioral responses to it (in terms of reads, “clicks,” links) over time. We are also interested in how key events can trigger drops or spikes in engagements around particular topics. Distortion of science in online (social media) spaces inappropriately raises the risk profile of good technologies which results in delays in getting socially vital products to the market, or shelved or unrealized innovations, and even the loss of important research through vandalization of field trials. Disinformation has been used to problematize science, influencing public opinion, affecting scientific integrity, and impeding science’s social license to operate. This, in turn, results in policies developed based on disinformation rather than scientific evidence. The disinformation landscape needs to be better understood across science, food production and security, and public health.

Key words: disinformation, misinformation, attention economy
140 Past and Future Changes in Scientific Publishing
Authors: Lalu Manoj M
Published: October 2021

Publication in scientific journals remains the primary method to disseminate research findings; however, the landscape of scientific publication is rapidly changing. For instance, although open access publication has led to unprecedented opportunities to share information with the global scientific community, it has also contributed to the rise of “predatory journals.” These journals accept fees to publish articles without promised quality checks (e.g. peer review). In order to better understand current publication practices and the threat predatory journals pose, this session will: 1) Briefly summarize the history of scientific publication and how the current model of peer-reviewed publication developed. 2) Define predatory journals and review components of the international consensus definition (false or misleading information, deviation from best editorial and publication practices, lack of transparency, aggressive/indiscriminate solicitation; Nature doi.org/10.1038/d41586-019-03759-y). 3) Summarize empirical studies that have assessed the current burden of predatory journals. A broad group of stakeholders are affected by these journals, including researchers and the public. 4) Provide a practical approach for audience members to distinguish between predatory and legitimate journals. 5) Highlight some key developments that will lead to new publication models in the future.
142 Open Science: Improving Access and Reducing Bias in Science
Authors: Fox Nick
Published: October 2021

The promise of science lies in the discovery of basic knowledge, new treatments for disease and possible solutions to the world’s problems. Fulfilling this promise requires confidence that the findings of published science are valid—that they represent an unbiased conclusion based on available data. In recent years, however, a “reproducibility crisis” has emerged indicating that published findings across research fields may be less credible than they seem, perhaps due to hidden biases in the research process. This talk will provide an overview of the key challenges that reduce the credibility and reproducibility of research and will discuss how open science practices address these challenges. Current practice is sustained by a dysfunctional incentive structure that prioritizes publication over accuracy. Changing the research culture to prioritize “getting it right” over “getting it published” requires nudges to the incentive landscape, while still fueling the engine of innovation and discovery that drives science into new domains.
169 Estimating the Environmental Impact of Livestock Operations Using the Canadian Whole-farm Model Holos Developed for Canadian Farmers
Authors: Kroebel Roland , Alemu Aklilu , Pogue Sarah , McPherson Aaron
Published: October 2021

The Holos model is a Canadian whole-farm model that uses IPCC Tier II emission factors to calculate greenhouse gas (GHG) emissions from Canadian farming systems. These Tier II emission factors are Canada-specific with respect to land-based nitrous oxide emission, but are universal with respect to the livestock calculation. Here, however, Tier II is limited to ruminant animals, as so far only Tier I models are available for monogastrics. The model is designed to permit farmers to enter readily available farm management information themselves in order to calculate GHG sources and management driven mitigation practices. The presentation will provide an overview of the model and its design (interface and algorithms), and will showcase some of the scientific studies (cradle-to-farmgate) that were accomplished using the Holos model for assessing the carbon footprint of Canadian beef and dairy production systems.
170 Effectiveness of On-line Webinars for Delivering Extension Education to Beef Producers Throughout the COVID-19 Pandemic
Authors: VanValin Katherine , Bullock Darrh , Anderson Leslie , Laurent Kevin , Lehmkuhler Jeffrey W
Published: October 2021

In response to the COVID-19 pandemic, all in-person Extension programs in Kentucky were canceled in March 2020. In order to continue reaching beef producers, a webinar series was developed. The initial series was eight weekly evening sessions. Sessions were streamed live on a video meeting and social media platform and were recorded for future viewing. Programs consisted of a presentation followed by a question-and-answer session, covering multi-disciplinary topics related to beef management. Following each session, participants were asked to complete a survey to gauge the effectiveness of the programs using a series of questions with responses on a 5-point Likert scale. The average number of responses was 17 and ranged from 4–31 respondents per session. Knowledge level before and after the presentation was asked for a given topic to assess the increase in subject awareness/understanding (1: not very knowledgeable; 5: very knowledgeable). The average response across all respondents (n = 138) for pre-program knowledge was 2.98, and the average response post-program was 4.37. This represented a 46.6% change across all topics covered in the post-attendance surveys. The most common age demographic represented by survey respondents was 50–59 years of age, and 84% of respondents reported previously participating in a webinar. Participants were asked to evaluate the webinar technology in terms of its ease of access (1: not very easy; 5: very easy), and the average response was 4.64. Participants were asked to evaluate the material presented in each session for its usefulness (1: not very useful; 5- very useful), and the average response was 4.71. When asked if the webinar was an effective use of time (1: not very useful; 5: very useful), the average response was 4.8. Overall, webinars were an effective means of delivering Extension education related to beef cattle management in the midst of the COVID-19 pandemic.
176 Evaluating Dual-purpose Wheat Varieties in the Southeastern U.S
Authors: West Micayla H , Carrell Russell C , Dillard Sandra L
Published: October 2021

Dual-purpose wheat (Triticum aestivum L.) systems increase farm sustainability by diversifying on-farm income. While these systems are common in the Southern Great Plains of the United States, they are not often utilized in the Southeast. This study aimed to evaluate pre- and post-grazing herbage mass (HM) of four winter wheat varieties managed under a dual-purpose grazing and grain production system. The winter wheat varieties evaluated were generic feed-type wheat (mixed variety, Feed), seed-type wheat (‘GA Gore’) and two forage-type varieties, ‘AGS 2024’ (AGS) and ‘Pioneer 26R41’ (Pioneer). The experiment was a completely randomized block design with n = 4. Each plot was randomly assigned either as no-grazing (CON) or grazing (GF2). Plots were grazed with cow-calf pairs that were fasted 24 h before each grazing event. Grazing was considered complete when the average stubble height was 10 cm. Herbage mass was determined using three 0.1m2-quadrats per plot and clipping to a 10 cm stubble height before (PreG) and after (PostG) each grazing event. Forage samples were then dried at 45°C for 72 h. Data were analyzed using PROC GLIMMIX of SAS (SAS Inst., Cary, NC). Differences were declared at P < 0.05. Initial HM was greater for PreG than PostG (883 and 615 kg/ha, respectively; P < 0.01). Prior to grazing, AGS (1204 kg/ha) was greater (P < 0.02) than all other varieties. Pre-grazing, there were no differences among the other varieties (776 kg/ha; P > 0.14). Post-grazing, AGS had a greater HM than Seed (788 and 391 ka/ha, respectively; P = 0.04), while all other varieties were intermediate (642 kg/ha). Herbage mass was affected by grazing frequency with CON being greater (P < 0.01) than GF2 (993 and 691 kg/ha, respectively). These results indicate that both wheat variety and grazing treatment had an effect on dual-purpose wheat herbage mass.
180 Effects of Forage Mixtures on Rumen Fermentation Parameters as Assessed by Continuous Culture
Authors: Snider Miriam A , Johnson Jacqueline M , Ziegler Sara E , Darby Heather M , Greenwood Sabrina L
Published: October 2021

The impact of using diverse forage mixtures on rumen performance is poorly characterized. The objective of this study was to evaluate the impact of feeding diverse pastures on rumen performance using in vitro continuous culture fermenters. Treatments were assessed using a 4 x 4 Latin square design. Each 10-d period included 7-d of adaption followed by 3-d of sample collection. Dietary treatments (DM basis) included 1) 50% orchardgrass + 50% alfalfa (OG-ALF); 2) 50% OG-ALF + 50% red clover (RC); 3) 50% OG-ALF + 50% pearl millet (MIL); and 4) 50% OG-ALF + 50% sorghum x sudangrass (SUD). Forage diets (131 g DM/ fermenter/ d) were divided into 4 portions/d (33%, 0600 h; 17%, 0720 h; 33%,1800 h; 17%, 1920 h). Fermenter pH measurements were collected every min for the entire experiment. Methane concentrations were measured using a gas probe and recorded twice daily (0530 h,1730 h) in triplicate on d 7, 8, 9, and 10. Daily total effluent samples were collected on d 8, 9, and 10 for VFA analysis. Results were analyzed using PROC MIXED of SAS. There were no differences in total VFA concentrations (P = 0.08), molar proportions (P = 0.22), or individual VFA ratios (P > 0.05) as a result of treatment. Fermenter pH did not differ between fermenters as a result of treatment (P > 0.05). Fermenters receiving OG-ALF had the greatest methane concentration (50.8 mg/dL), which was higher (P < 0.05) than methane concentrations in fermenters receiving MIL (6.2 mg/dL), SUD (6.9 mg/dL), or RC (21.2 mg/dL). Methane concentrations from the MIL, SUD and RC treatments did not differ (P > 0.05). This indicates that binary forage mixtures may have lower nutritional value compared with diverse mixtures, and this diversification could provide nutritional benefits.
189 Techniques in Teaching Forages to Animal Scientists
Authors: Naumann Harley D
Published: October 2021

How do you teach a plant-based course focused on forage physiology, production and management to an animal science student? How do you engage them and keep them engaged? Empathy. Put yourself in the shoes of the animal science student who is sitting in a plant-science course. Make it applied and relatable to the animal scientist. In this talk I will take a case-study approach to sharing my experience as an animal science student tasked with knowing something about plants and how I use that experience to guide my teaching methods in a Forages course at the University of Missouri.
191 Pulsatile Administration of Leucine Promotes mTOR Signaling and Protein Synthesis in Skeletal Muscle of Continuously Fed Preterm Pigs
Authors: Rudar Marko , Suryawan Agus , Nguyen Hanh , Stoll Barbara , Burrin Douglas , Fiorotto Marta , Davis Teresa A
Published: October 2021

Continuous feeding does not elicit an optimal anabolic response but is required for some premature infants. We reported previously that intermittent intravenous pulses of Leu (800 μmol Leu·kg-1·h-1 every 4 h) to continuously fed pigs born at term enhanced skeletal muscle mTOR signaling and protein synthesis (PS). The objective of this study was to determine if the anabolic response of skeletal muscle to intermittent Leu pulses is altered following premature birth. Pigs delivered 10 d preterm by cesarean section were advanced to full oral feeding over four days (195 kcal·kg-1·d-1; 13.5 g protein·kg-1·d-1). Pigs were assigned to 1 of 4 treatments: 1) ALA (continuous feeding; 800 μmol Ala·kg-1·h-1 every 4 h; n = 7); 2) L1× (continuous feeding; 800 μmol Leu·kg-1·h-1 every 4 h; n = 6); 3) L2× (continuous feeding; 1600 μmol Leu·kg-1·h-1 every 4 h; n = 6); and 4) INT (intermittent feeding every 4 h; n = 5). Pigs received a Phe tracer 30 min following the amino acid pulse or intermittent feeding to measure PS in longissimus dorsi muscle. Anabolic signaling downstream of mTOR was determined by immunoblot.ResultsPS was higher in L2× and INT compared to ALA (P < 0.05) but was not different between L2× and INT; PS in L1× was intermediate and not different from other groups. Phosphorylation of 4EBP1 and S6K1 was higher in INT compared to L1× and ALA groups (P < 0.05) but was not different compared to L2×. Phosphorylation of 4EBP1, but not S6K1, was higher in L2× compared to ALA (P < 0.05); phosphorylation of 4EBP1 and S6K1 was not different between L1× and L2×.ConclusionsThese results demonstrate that intravenous Leu enhances mTOR activation and PS in LD muscle of continuously fed preterm pigs. However, the amount required may be higher than in pigs born at term.Source of Research SupportNIH and USDA.
192 Identification of Fos and FosB as Transcriptional Regulators of Bovine Satellite Cell Differentiation
Authors: Lyu Pengcheng , Settlage Robert , Jiang Honglin
Published: October 2021

Transcription factors (TFs) are key regulators of gene expression during cell differentiation. Four TFs including Myf5, MyoD, MyoG and Myf6 have been identified as key myogenic regulatory factors (MYFs) that regulate gene transcription during myogenesis. Satellite cells (SCs) are the myogenic precursor cells in adult skeletal muscle. The objective of this study was to identify additional TFs that control the differentiation of bovine satellite cells. Bovine satellite cells (bSCs) were isolated from 4 crossbred steers and were initially cultured in growth medium for 12 days to expand and then in differentiation medium for 48 hours to differentiate. Chromatin immunoprecipitation followed by sequencing (ChIP-seq) was performed to identify chromatin regions marked with acetylation of histone H3 on lysine 27 (H3K27ac). This ChIP-seq analysis revealed 3,348 and 38,800 H3K27ac-associated chromatin regions in bSCs before and after differentiation, respectively. A motif enrichment analysis of the H3K27ac-marked chromatin regions from the differentiated bSCs indicated the enrichment of binding sites for the 4 MYFs and many other TFs including Fos and FosB. RNA-sequencing revealed the upregulation of Fos and FosB mRNAs in bSCs from growth to differentiation. To verify the roles of Fos and FosB in bSC differentiation, their expressions in bSCs were reduced by siRNA-induced knockdown. Based on qRT-PCR analyses, expressions of MYH2, MYH3, MYOG, and CKM mRNAs, which were selected as markers of muscle cell differentiation, were increased (P < 0.05) in bSCs from growth to differentiation, but the increases in at least three of them were reversed (P < 0.05) by Fos or FosB knockdown. Taken together, these results establish Fos and FosB as transcriptional regulators of bovine satellite cell differentiation.
193 Single Cell RNA-sequencing Reveals a Role of Lipid Metabolism in Muscle Satellite Cells
Authors: Kuang Shihuan , Yue Feng , Oprescu Stephanie
Published: October 2021

Single Cell RNA-sequencing (scRNA-seq) is a powerful technique to deconvolute gene expression of various subset of cells intermingled within a complex tissue, such as the skeletal muscle. We first used scRNA-seq to understand dynamics of cell populations and their gene expression during muscle regeneration in murine limb muscles. This leads to the identification of a subset of satellite cells (the resident stem cells of skeletal muscles) with immune gene signatures in regenerating muscles. Next, we used scRNA-seq to examine gene expression dynamics of satellite cells at various status: quiescence, activation, proliferation, differentiation and self-renewal. This analysis uncovers stage-dependent changes in expression of genes related to lipid metabolism. Further analyses lead to the discovery of previously unappreciated dynamics of lipid droplets in satellite cells; and demonstrate that the abundance of the lipid droplets in newly divided satellite daughter cells is linked to cell fate segregation into differentiation versus self-renewal. Perturbation of lipid droplet dynamics through blocking lipolysis disrupts cell fate homeostasis and impairs muscle regeneration. Finally, we show that lipid metabolism regulates the function of satellite cells through two mechanisms. On one hand, lipid metabolism functions as an energy source through fatty acid oxidation (FAO), and blockage of FAO reduces energy production that is critical for satellite cell function. On the other hand, lipid metabolism generates bioactive molecules that influence signaling transduction and gene expression. In this scenario, lipid metabolism and FAO regulate the intracellular levels of acetyl-coA and selective acetylation of PAX7, a pivotal transcriptional factor underlying function of satellite cells. These results together reveal for the first time a critical role of lipid metabolism and lipid droplet dynamics in muscle satellite cell fate determination and regenerative function; and underscore a potential role of dietary fatty acids in satellite cell-dependent muscle development, growth and regeneration.
500 Late-Breaking: Heart Rate During Exercise Is Positively Correlated with State IV Mitochondrial Respiration in the Equine Skeletal Muscle
Authors: Kawaida Mia Y , Kwon Oh-Sung , Anh Ahram , Reiter Amanda S , Tillquist Nicole M , Reed Sarah A
Published: October 2021

Mitochondria are critical for oxidative phosphorylation in skeletal muscle, especially in athletic species such as the horse. Mitochondrial respiration increases with physical exercise, but the relationship between mitochondrial respiration and cardiovascular functions are not well described in the horse. The objective of this study was to determine if there is a relationship between heart rate (HR) during and after submaximal exercise tests (SETs) and skeletal muscle mitochondrial respiration in polo ponies. We hypothesized that horses with greater maximum HR and average HR during the exercise tests would have greater mitochondrial respiration in skeletal muscle. Twelve fit polo ponies (14.8 ± 1.7 years old, 10 mares and 2 geldings) were equipped with Polar equine heart rate monitors (Polar Electro Inc., Lake Success, NY) and underwent 26-minute SETs designed to mimic a polo chukker followed by a 30-minute recovery period. Muscle biopsy samples from the semitendinosus muscle were taken 2 weeks prior to the SET to determine mitochondrial oxygen consumption using the Oroboros O2k high-resolution respirometer (Oroboros Instruments, Innsbruck, Austria). Data were analyzed using the PROC CORR procedure (SAS Inst. Inc., Cary, NC). Correlations were considered strong at r > 0.6 and significant at P < 0.05. Maximum HR during SET and state IV respiration were positively correlated (P = 0.02, r = 0.68). Average HR during SET and state IV respiration were also positively correlated (P = 0.01, r = 0.72). However, correlations between maximum and average HR and state III respiration were not as strong (P ≥ 0.05, r < 0.6). These data suggest that state IV mitochondrial respiration (proton leak) in equine skeletal muscle may impact cardiac responses to high-intensity exercise. Horses with higher HR during exercise may have less efficient oxidative phosphorylation, resulting in earlier fatigue and/or greater formation of reactive oxygen species resulting from proton leak.
204 Awardee Talk: Recent Advances in Protein Nutrition in Horses
Authors: Urschel Kristine
Published: October 2021

Protein has been recognized as an essential nutrient for animals for well over 100 years. Protein plays many important structural and metabolic roles, and some of its component amino acids have additional functions, including as regulatory molecules, as energy substrates and in the synthesis of other non-protein molecules. Skeletal muscle makes up approximately 50% of body weight in horses, with protein being the major non-water component. As an athletic species, the development and maintenance of muscle mass is of the utmost importance in horses. Because muscle mass is largely determined by the balance of rates of muscle protein synthesis and breakdown, understanding how these pathways are regulated and influenced by dietary protein and amino acid provision is essential. Historically, much research regarding protein nutrition in horses has focused on the protein digestibility of different feed ingredients, and the adequacy of different protein sources in supporting the growth and maintenance of horses. This presentation will focus on some of the current areas of active research relating to protein nutrition in horses: the activation of the signaling pathways that regulate muscle protein synthesis, amino acid supplementation in athletic horses, protein metabolism in aged and horses and those with insulin dysregulation, and amino acid and protein nutrition in predominantly forage-fed horses. There are many exciting opportunities for future research in the area of protein and amino acid nutrition in horses across the lifespan.
213 Nutritional and Genetic Influences on Fatty Acid Composition of Beef and Lamb
Authors: Duckett Susan K , Thomas Alexandra R , Udoka Aliute , Greene Maslyn A
Published: October 2021

There is increased competition in the protein market with the entrance of cell-based and plant-based products. Consumers issues with consumption of red meat typically center around saturated (SFA) fatty acid content and environmental impacts associated with production. Nutritional system used for finishing beef and lamb alters fatty acid composition of the meat product. Forages and grasses that are utilized in a grass-fed finishing system increases the animal’s intake of a-linolenic acid (C18:3 n-3), the main fatty acid present in plants (57%) that can be converted to eicosapentaenoic (C20:5 n-3), docosapentaenoic (C22:5 n-3) and docosahexaenoic (C22:6 n-3) acids in animal tissues. Grain-fed finishing systems increases the animal’s intake of linoleic acid (C18:2 n-6), the main fatty acid present in corn grain (57%), that can be converted to arachidonic acid (C20:4 n-6) and docosatetraenoic acid (C22:4 n-6) in animal tissues. Biohydrogenation of polyunsaturated fatty acids (PUFA) is extensive in the rumen (> 80% of dietary PUFA) and rumen protected supplements are needed to enhance PUFA content of ruminant meat products. Saturated (SFA) and monounsaturated (MUFA) fatty acids are the majority (>75% of total fatty acids) of fatty acids present in ruminant meat products. Therefore, finding approaches to attain greater desaturation of palmitic and stearic acids to their MUFA products, palmitoleic and oleic acids, would be most beneficial. The content of oleic acid and MUFA in beef is highly heritable and some breeds have high levels of MUFA. Stearoyl-CoA desaturase (SCD1) is the rate limiting enzyme in the production of MUFA. More research is needed to find ways of altering SCD1 expression in meat animal tissues to enhance MUFA and lower SFA content.
226 Integrated Pork Production During a Global Pandemic: Impact on the Live Production Supply Chain, Feed Mills, & Nutrition
Authors: Parks Chris , Shipp Tommy , Hoogland Marlin , Cordova Alejandro
Published: October 2021

The global COVID-19 pandemic of 2020/2021 resulted in widespread impacts on the production & processing of animal proteins. Specifically, the U.S. pork industry was hit with multiple, long-term plant closures and slow-downs due to labor safety issues and availability, resulting in a backlog reaction felt throughout the live production supply-chain. Impact and timing differed by region and required variable strategies to address them. While some plants in the Western United States weren’t impacted until the latter stages of the pandemic and thus were attempting to add valuable liveweight, other regions, including the Midwest and Southeastern United States were experiencing moderate to severe reductions in processing capacity that created an accumulation of heavy animals and placed additional feed and ingredient demands on the feed mills. The backlog also reduced available space & disrupted the normal barn fill/empty cycles. While there was no way to prepare for these impacts, university & industry groups attempted to fill the knowledge gap with management and nutritional tools to address the issues of excess inventory, decreasing feed capacity, and supply-chain disruptions. Numerous approaches were employed, including altered grading strategies, sow breeding target reductions, double/triple stocking situations, and feed, ingredient, and nutrient manipulation meant to slow down growth rate and feed intake. Nutritional strategies included the feeding of low energy ingredients as well as low protein/high methionine diets designed to reduce the growth rate of both heavy and light animals. While several of these strategies resulted in moderate success, some resulted in additional issues including stress-related vices, ulcers, increased mortality, and sub-optimal carcass characteristics. Ultimately, continuous planning, coordination, and communication between the plants, feed mills, nutritionists, and production groups enabled a return to normalcy, and while we hope to never experience a pandemic again, we are left with knowledge that will improve the resilience of the U.S. pork industry.
230 Microalgae as an Alternative Feed Protein: Opportunities and Challenges
Authors: Lei Xingen
Published: October 2021

A major mission of the animal industry is to help protect global food security with little or no impacts on climate and environment. In fact, the global food security depends on a sustainable protein production and supply. Currently, there is a direct competition between feed and food protein need. As animal feeds use 70–80% of the produced soybean, alternative proteins are required to sustain the industry. This presentation will report research findings from three large consortium projects in exploring the dual application of microalgae as a new generation of feedstock for biofuel production and high-quality feed protein supply. A comprehensive review will be provided on effects of supplemental full- or de-fatted microalgal biomass in diets for broiler chickens, laying hens, pigs, and fish on their production performance, nutrient metabolism and molecular responses, and health values of their products. Discussions will be given on practical concerns over the production cost related to soybean meal, the production volume/scale for a constant supply, and the biosafety and acceptance as a regular ingredient. Future research will be proposed to synchronize the nutritional, health, and sustainability potential of microalgae as a viable feed protein source.
237 Incidence and Implications of Disparate Uterine and Ovarian Development Observed Among Heifers Evaluated During the Peripubertal Period
Authors: Smith Emily G , Thomas Jordan M , Spinka Christine
Published: October 2021

Rapid development in the reproductive tract occurs in the peripubertal period, with variable rates of development of reproductive tissues potentially resulting in perceived disparities in ovarian and uterine development at pre-breeding examination. Data collected from 22,173 heifers evaluated over five consecutive breeding seasons (2014–2018) were analyzed retrospectively to assess relationships between observed disparities in uterine and ovarian development and the timing of conception within the breeding season. Pre-breeding evaluations were conducted 35–45 days prior to breeding. Weight, hip height, and pelvic area were recorded. A single veterinarian conducted all reproductive evaluations via rectal palpation, and heifers were assigned individual scores for ovarian (2=infantile, 3=no significant structures, 4=large follicle and/or corpus luteum) and uterine (2=infantile, 3=mid-sized, distended tract, 4=well-vascularized, distended or coiled tract) development respectively. Heifers received artificial insemination (AI) based on detected estrus following the 14-day MGA-PG protocol. Pregnancy diagnosis was performed via transrectal ultrasonography. Pregnancy rates to AI (P/AI) were greater for scores 4-4 (n = 14,567) in comparison with 3-3 (n=3,941; P < 0.0001) or 2-2 (n = 44; P < 0.0001) and likewise were greater (P < 0.0001) for scores 3-3 in comparison with 2-2. Heifers with disparate scores of 2–3 (n = 38) did not differ (P = 0.53) from those with disparate scores of 3-2 (n = 53) with respect to P/AI, but either disparity was associated with greater (P < 0.01) P/AI relative to scores of 2-2 and reduced P/AI relative to scores of 3-3 (P < 0.01). Scores of 4-3 (1,698) and 3-3 did not differ (P >0.44) in P/AI, but P/AI tended (P = 0.06) to be greater among scores 3–4 (1,832) in comparison with 3-3. Similar (P > 0.33) P/AI was observed among heifers scored 4-4, 4-3, or 3–4. In summary, disparate ovarian and uterine development impacted timing of conception within the breeding season among heifers with lower tract scores. Such disparities were observed among 0.4% of heifers evaluated.
234 Pregnancy and Hormonal Response in Suckled Beef Cows Administered High-concentration Prostaglandin F2α in a 5-day CO-Synch + CIDR Synchronization Program
Authors: Ahmadzadeh Amin , Corpron McKenzie , Hall John B , Ahmadzadeh Amin , Dalton Joe
Published: October 2021

Two injections of prostaglandin F2 (PGF) in a 5-d CO-Synch+CIDR timed-AI protocol (5-d CIDR) is necessary to induce luteolysis and reduce serum progesterone (P4) concentrations by the time of AI in beef cattle. The objectives were to examine the effects of a single high-concentration dose of PGF in a 5-d CIDR protocol on P4 concentration and pregnancy per AI (P/AI) beef cows. Angus-Hereford cows (n = 404) were synchronized (d0) with a 5-d CIDR protocol and assigned to receive either one injection of high-concentration PGF on d5 (HC; total dose: 25 mg; n = 203) or two injections of conventional PGF (2PG; each injection: 25 mg; n = 201), at CIDR removal (d5) and 8 h later. All cows received AI at a fixed time 72 h after PGF treatment (d8). Pregnancy was determined by ultrasound 48–63 days after AI. For P4 and cyclicity determination, blood samples were collected on d -7, 0, and 8. Cyclicity status and proportion of cows with a CL at d0 did not differ between treatments. Proportion of cows detected in estrus was greater (P = 0.01) for 2PG (63.1%) than HC (49.3%). Treatment did not affect P/AI (P = 0.87; 51% vs. 52% for HC and 2PG, respectively). Serum P4 at AI also affected (P < 0.01) P/AI; as P4 concentration increased, P/AI decreased. ROC analysis showed a greater P/ AI when P4 was < 0.43 ng/mL. Fewer (P < 0.01) HC cows had P4 < 0.43 ng/mL at AI than 2PG (84.0 and 97.0%, respectively). Nonetheless, mean P4 concentrations at AI were less than 0.4 ng/mL for HC and 2PG. Although two doses of conventional PGF (total dose: 50 mg) more effectively reduced P4 to < 0.43 ng/mL by the time of AI than one dose of high-concentration PGF (total dose: 25 mg), P/AI was not different between treatments.
236 Factors Influencing Clearance of Pregnancy-associated Glycoproteins in Postpartum Beef Cattle
Authors: Kline Adalaide C , Walker Julie , Andrews Taylor , Zoca Saulo Menegatti , Epperson Kaitlin M , Quail Lacey , Rich Jerica J , Perry George A , Rhoades Jim R
Published: October 2021

Blood pregnancy tests can determine pregnancy status in cattle; however, pregnancy-associated glycoproteins (PAGs) have a long half-life (80 to 100 d). If tested too soon after calving, false positive readings can occur due to elevated concentrations from the previous pregnancy. This study’s objective was to determine factors that impact clearance of PAGs in postpartum beef females. Blood samples were collected from postpartum Angus and Angus-cross females (primiparous n = 46 and multiparous n = 58); once a week for up to 14 weeks after calving (range of first to last sample 1–7 to 98–105 days postpartum; dpp). Serum was tested in duplicate using the IDEXX Alertys Pregnancy Test. Data were analyzed as a repeated measure using the MIXED procedure of SAS (9.4) with parity, calf sex (sex), days postpartum, and all interactions in the model. Data were analyzed using the REG procedure in SAS. There was a significant effect of dpp (P < 0.01) on PAG concentrations; however, PAG concentrations were not influenced by parity (P = 0.24), sex (P = 0.49), parity by dpp (P = 0.12), parity by sex (P = 0.65), sex by dpp (P = 0.37), or parity by sex by dpp (P = 0.99). Concentrations of PAGs rapidly decreased from d 0 to 50 postpartum and then continued to gradually decrease to d 100. Days postpartum accounted for 67.53% of the variation in PAG concentrations. Prior to 50 dpp, PAG concentrations were sufficiently elevated which resulted in false positive readings (S – N ≥ 0.3). In summary, concentrations of PAGs remained elevated after calving, but the clearance of PAGs were not impacted by parity or sex of the calf. Clearance of PAGs were significantly influenced by days postpartum. Additionally, using a blood pregnancy test prior to d 50 postpartum would increase the likelihood of false positive readings due to residual PAG concentrations from the previous pregnancy.
241 Skeletal Muscle Mitochondrial Capacities Are Impacted by Breed and Temperament in Young Angus and Brahman Steers
Authors: Guy Chloey P , Wesolowski Lauren T , Earnhardt Audrey L , Law Dustin , Neuendorff Don A , Long Charles R , Perry George A , Randel Ron D , Welsh Thomas H , White-Springer Sarah H
Published: October 2021

Temperament impacts skeletal muscle mitochondria in Brahman heifers, but this has not been investigated in steers or between cattle breeds. We hypothesized mitochondrial measures would be greater in Angus than Brahman, temperamental than calm steers, and the trapezius (TRAP) than the longissimus thoracis (LT) muscle. Samples from calm (n = 13 per breed), intermediate (n = 12 per breed), and temperamental (n=13 per breed) Angus and Brahman steers (mean±SD 10.0±0.8 mo) were evaluated for mitochondrial enzyme activities via colorimetry. Calm and temperamental LT samples were evaluated for oxidative phosphorylation (P) and electron transfer (E) capacities by high-resolution respirometry. Data were analyzed using linear models with fixed effects of breed, muscle, temperament, and all interactions. Brahman tended to have greater mitochondrial volume density (citrate synthase activity; CS) than Angus (P = 0.08), while intrinsic (relative to CS) mitochondrial function (cytochrome c oxidase activity) was greater in Angus than Brahman (P = 0.001) and greater in TRAP than LT (P = 0.008). Angus exhibited greater integrative (per mg tissue) and intrinsic P with complex I (PCI), P with complexes I+II (PCI+II), maximum noncoupled E, and E with complex II (ECII; P ≤ 0.04) and tended to have greater intrinsic leak (P = 0.1) than Brahman. Contribution of PCI to total E was greater in Angus than Brahman (P = 0.01), while contribution of ECII to total E was greater in Brahman than Angus (P = 0.05). A trend for the interaction of breed and temperament (P = 0.07) indicated calm Angus had the greatest intrinsic ECII (P ≤ 0.03) while intrinsic ECII was similar between temperamental Angus and calm and temperamental Brahman. Integrative PCI+II and ECII, and the contribution of PCI and PCI+II to overall E tended to be greater in temperamental than calm steers (P ≤ 0.09), while intrinsic ECII tended to be greater in calm than temperamental steers (P = 0.07). The impact of these mitochondrial differences on meat quality measures remains to be determined.
244 Fertility Outcomes Associated with Reproductive Tract Cytokines and Microbiota in Postpartum Beef Cows
Authors: Poole Rebecca K , Ault-Seay Taylor B , Payton Rebecca R , Myer Phillip R , Lear Andrea S , Pohler Ky G
Published: October 2021

Local immune activity in the reproductive tract is crucial in the response to uterine diseases, normal reproductive functions, and establishing pregnancy. Few studies have evaluated the influence of the local immune environment of the reproductive tract on fertility outcomes. The objectives were to 1) evaluate reproductive cytokine concentrations in postpartum cows undergoing estrus synchronization followed by timed artificial insemination (TAI) and 2) correlate reproductive bacterial communities with cytokine concentrations. Angus cows (n = 20) were subjected to a 7-Day Co-Synch protocol with pre-synchronization beginning 21 days prior (d -21) to TAI (d 0). Uterine and vaginal flushes were collected on d -21 and -2. Pregnancy was determined by transrectal ultrasound on d 30. Bacterial community profiling and analyses were conducted targeting the V1 to V3 hypervariable regions of the 16S rRNA gene. Cytokine concentrations for interleukin (IL)-1b, IL-6, IL-10, and transforming growth factor beta (TGF-β) were determined by commercial ELISA kits. Concentration data were analyzed using PROC MIXED and correlations using Pearson correlation in SAS. No differences were detected in vaginal samples (P >0.05). No differences in IL-10 or IL-1b concentrations were detected in uterine samples (P >0.05). Uterine TGF-β concentrations were greater in resulting pregnant than non-pregnant cows (44.0 ± 13.4 pg/mL vs 14.7 ± 4.9 pg/mL; P = 0.05). Uterine TGF-β was negatively correlated with the relative abundance of genera Treponema (r = -0.668; P = 0.05) in resulting non-pregnant cows on d -21. Uterine IL-6 concentrations were greater in resulting non-pregnant than pregnant cows (198.7 ± 21.8 pg/mL vs 144.3 ± 16.1 pg/mL; P = 0.05). Uterine IL-6 and the relative abundance of genera Butyrivibrio were positively correlated (r = 0.742; P = 0.02) in resulting non-pregnant cows on d -21. These results suggest possible relationships between uterine bacterial communities and cytokines prior to TAI that may ultimately affect fertility outcomes in beef cattle.
250 Effect of Pre- and Post-ai Nutrition on Ovarian Dynamics, Steroidogenesis, and Expression of Estrus in Beef Heifers
Authors: Epperson Kaitlin M , Rich Jerica J , Zezeski Abigail L , Zoca Saulo Menegatti , Walker Julie , Geary Tom W , Perry George A
Published: October 2021

The objective of this study was to evaluate nutrition before and after artificial insemination (AI) on follicular dynamics, expression of estrus, and steroidogenesis. Seventy-nine beef heifers were randomly assigned to one of two dietary treatments (High;155% and Low;86% of maintenance energy) 30d prior to AI. Estrus was synchronized (PG 6-d CIDR protocol) and heifers received AI (d0) 8 to 12h following onset of estrus. On d0, heifers were randomly reassigned diets generating four Pre-x-Post-AI nutritional treatments; High-High (HH, n = 20), High-Low (HL, n = 20), Low-High (LH, n = 19), and Low-Low (LL, n = 20). Heifers remained on new diet treatments until embryo collection (flush; d7-8). Blood samples were collected daily from d-3 to d0, and on d1, 3, 5, 7 and 8 for plasma concentrations of estradiol (E2) and progesterone (P4). Dominant follicle diameter was evaluated on d-3 and d0, and CL diameter was recorded at flush. Statistical analyses were completed in SAS using the MIXED (body weight, E2, P4), GLIMMIX (expression of estrus), and GLM (ovarian parameters, interval to estrus) procedures. There were Pre-AI (P < 0.0001) and Post-AI by time (P < 0.0001) interactions on body weight; heifers in high and low treatments gained and lost weight, respectively, during both periods. Estradiol concentrations increased (P < 0.0001) from d-3 (2.18±0.15pg/mL) to d0 (6.05±0.04pg/mL). Pre-AI diet increased the proportion of heifers in estrus (80±6.3% vs. 59±7.9%; P = 0.05), and dominant follicle size (11.7±1.42mm vs. 10.68±1.33mm; P = 0.0016) in High vs. Low, respectively. Additionally, High Pre-AI heifers had greater P4 after AI compared to Low Pre-AI heifers (4.85±0.37ng/mL vs. 3.53±0.38ng/mL; P = 0.015). Post-AI treatment did not influence concentrations of P4 (P = 0.88). There was no effect of Pre, Post or Pre-x-Post-AI treatment on initial follicle size, follicle growth rate, E2 concentrations, interval to estrus, or CL size at flush (P > 0.10). In conclusion, nutrient restriction before AI negatively impacted ovarian function, steroidogenesis, and expression of estru.
264 Using in vivo RNA Interference to Investigate Ruminant Placental Function
Authors: Anthony Russell V , Tanner Amelia R , Lynch Cameron S , Kennedy Victoria C , Rozance Paul J , Winger Quinton A
Published: October 2021

Pregnant sheep have been used extensively for investigating pregnancy physiology, providing valuable information about the progression of ruminant pregnancy. The ability to place indwelling catheters, within both maternal and fetal vessels, allows for steady-state investigation of blood flow, nutrient uptakes and utilization, and hormone secretion, under non-stressed and non-anesthetized conditions. As such, our understanding of the in vivo physiology of pregnancy in sheep is unrivalled by any other species. However, until recently, a significant deficit existed in determining the specific function or significance of individual genes expressed by the placenta in livestock. To that end, we developed and have been using in vivo RNA interference (RNAi) within the sheep placenta to examine the function and relative importance of genes involved in conceptus development (PRR15 and LIN28), placental nutrient transport (SLC2A1 and SLC2A3), and placenta derived hormones (CSH). The lentiviral vector LL3.7 is used to generate virus that is stably integrated into the infected cell’s genome, thereby expressing a short-hairpin RNA (shRNA), that when processed within the cell, combines with the RNA Induced Silencing Complex (RISC) resulting in specific mRNA degradation or translational blockage. To accomplish in vivo RNAi, day 9 hatched and fully expanded blastocysts are infected with the lentivirus for 4–5 hours, and then surgically transferred to synchronized recipient uteri. Only the trophectoderm cells are infected by the replication deficient virus, leaving the inner cell mass unaltered, and we typically obtain 70–80% pregnancy rates following transfer of a single blastocyst. Data will be presented from two projects. One is focused on generating a deficiency in placental glucose transporters at mid-gestation, and the other on the impact of CSH RNAi during late gestation, demonstrating the utility of this experimental approach for examining gene function within the placenta of livestock. Supported by NIH-NICHD grants HD093701 and HD094952.
260 Effect of Dam Nutrition on Offspring Reproductive Performance
Authors: Hall John B
Published: October 2021

Domestic ruminants utilize extensive pasture and rangelands as a primary source of nutrition. These forage sources vary greatly in nutritional content and availability due to season, plant species and climatic factors. Therefore, ruminants are exposed to nutrient excesses and deficiencies at varying points during the reproductive cycle. The objectives of this presentation are 1) to review our understanding of the impact of nutritional changes experienced by the dam during gestation on subsequent reproductive performance of female offspring, 2) examine the timing and duration of nutrient restriction on indicators of fertility in domestic ruminants and 3) compare responses under production conditions to mechanisms determined in controlled experiments. Depending on the time and severity of the nutrient deprivation, physiological effects include reduced gonadal weight, reduction in 2° and 3° follicles, alterations in the hypothalamic-pituitary axis, fetal weight and attainment of puberty. Anti-Müllerian hormone (AMH) and antral follicle count (AFC) are indicators of fertility in ruminants. Severe nutrient deprivation of heifers during the first trimester of gestation reduced AMH and AFC in female offspring. In contrast, a more moderate nutritional challenge to mature cows during early gestation did not result in changes in AMH and AFC in female offspring. Heifers from dams that grazed protein deficient range during the third trimester had delayed puberty onset and reduced pregnancy rates compared to heifers from supplemented dams. Recently, we compared indictors of fertility in heifers from dams that grazed range or irrigated pastures during the first two trimesters. Based on preliminary data, cows that grazed range were nutritionally challenged; however, heifers from range dams did not appear to differ in indicators of fertility from heifers from dams grazing irrigated pastures. Continued investigations on impacts of maternal nutrition on reproduction in offspring under production conditions are warranted.