Come for the dairy nutritionist banter—stay for the fascinating advancements in rumen microbiome science. In episode five, Matt sits down with Jeff Firkins, a dairy microbiologist and nutritionist at The Ohio State University and senior editor at the Journal of Dairy Science at the 2023 ADSA Annual Meeting. The two friends and colleagues reflect on lessons learned from the ruminant nutrition symposium on rumen microbiota—reviewing the forward leap dairy science has taken in understanding the thousands of microbial species in the rumen. Jeff explains his work on rumen fermentation and nutrient–rumen microbiota interactions, along with how he works directly with dairy farmers to think through nutrition challenges in their herds. Matt and Jeff dive into the state of dairy in Ohio and share their mutual respect for the incredible work dairymen perform in the field. Finally—just for you, listeners!—Jeff peers into his crystal ball and shares what he sees as the most promising approaches to improving cow efficiency and reducing methane production—from soil amendments like biochar to feed additives, improvements to forage quality, and more.

Episode Five Show Notes
Learn more about Dr. Jeff Firkins.
Check out the ADSA Annual Meeting sessions mentioned in the episode and save the date for the 2024 Annual Meeting:
Ruminant Nutrition Symposium: Improving Rumen Fermentation Through Altering Rumen Microbiota
Ruminant Nutrition Symposium: Dairy Nutrition to Improve Feed Utilization—Recognizing the Contributions of ADSA Fellow Dr. Bill Weiss

Dairy Nutrition and Managing the Rumen Microbiome for Productivity and Sustainability with Jeff Firkins, PhD

Welcome to Dairy Digressions, the podcast from the American Dairy Science Association. Every other month, host Matt Lucy, PhD, explores the latest developments, fascinating discoveries, and breaking trends in the world of dairy science. 

From pioneering technologies to innovative research, we cover a range of topics related to the dairy industry and go behind the scenes of the top labs and minds in dairy research. Listen in as we dig deep into the science of dairy and discover what’s new and exciting in this ever-evolving field.

Natural Sciences

Science & Medicine

Science

Deep dive with us into the exciting world of stem cell research as we welcome Carl Jiang, PhD, associate professor at the University of Florida and member of the University of Florida Genetics Institute. Jiang’s work focuses on reproductive biology, with an emphasis on understanding the epigenetic mechanisms during the embryo-development period when most pregnancy losses occur. Carl and host Matt Lucy get caught up during the International Embryo Technology Society’s 50th Annual Conference and discuss Carl’s path from growing up in rural China to studying embryology after being encouraged by an undergraduate mentor. The two explain the importance of bovine pregnancy success and how our understanding of the mechanisms of blastocysts—the embryo’s early stage—has been hampered by a limited supply of embryos. In a remarkable breakthrough, however, Carl and his team developed an efficient method to assemble bovine blastoids—bovine blastocyst–like structures—via trophoblast stem cells. Although still in the early stages, this technology opens up a more accessible in vitro model for studying embryo development and helping to potentially reduce pregnancy loss and improve reproductive efficiency in tomorrow’s dairy herds. Carl also lets us behind the scenes of his lab, explaining why one-on-one mentorship and a diversity of voices from around the globe are so important to research success. Finally, he explains why “Journal Club Day” is his favorite day at work and how it can kickstart new ideas and a renewed passion for science. 
Episode Fifteen Show Notes
Learn more about Carl Jiang’s work and connect with him on LinkedIn and Twitter/X. 
Save the date for the 51st International Embryo Technology Society Annual Conference (January 18–21, 2025, in Fort Worth, TX). 
Start earning rewards and journal savings via the ADSA Loyalty Rewards Program for the Journal of Dairy Science and JDS Communications. 
Catch up on the papers discussed in the episode:
Establishment of bovine trophoblast stem cells, Cell Reports (2023)
Bovine blastocyst-like structures derived from stem cell cultures, Cell Stem Cell (2023)






Assembled Bovine Blastoids, the Future of Repro Efficiency, and the Importance of Science as a Global Endeavor with Carl Jiang, PhD

We don’t pick favorites among our guests, but we’re especially thrilled to welcome Jessica A. A. McArt, DVM, PhD, DABVP (Dairy Practice), to the pod! Jess is the new Editor in Chief of JDS Communications and associate professor of ambulatory and production medicine at Cornell University’s College of Veterinary Medicine, where her McArt Dairy Cow Lab focuses on improving cowside detection and the prevention of periparturient disease. Matt and Jess discuss her journey into dairy science—from growing up in Alaska to helming JDS Communications to wrestling with the shocking fact that only 14% of scientific journal editors are women and only 8% are editors in chief. The two discuss the very real systemic gender inequality in academia, its effects on a career in dairy science, and the role these forces play in the current shortage of large-animal veterinary practitioners. Looking to the future, Jess outlines her vision for JDS Communications and her challenge for our community to question assumptions and welcome diverse voices. Taking listeners into her research, Jess explains her recent findings on early lactation disease markers, including hyperketonemia and hypocalcemia–plus an explanation of dyscalcemia, a new term in the scientific milieu that originated in her lab. Finally, Jess leaves us with the best advice she received as a young researcher and the reasons she advises her students and mentees to say “yes” to opportunities—even if it pushes them outside of their comfort zone.  

Fostering Belonging in Our Community, Academia’s Gender Inequality, and Early Lactation Disease Markers with Jessica A. A. McArt, DVM, PhD, DABVP (Dairy Practice)

Join us for a special episode of Dairy Digressions recorded live at the International Embryo Technology Society’s 50th Annual Conference. Between sessions, host Matt Lucy sat down with Goetz Laible, PhD, biochemist and principal scientist at AgResearch and honorary associate professor at the University of Auckland in New Zealand. Their discussion walks listeners through Goetz’s work in developing and evaluating technologies for the genetic improvement of livestock. In the face of our warming climate, Goetz and his animal biotechnology team are working to advance gene-editing technology to help dairy herds cope better—and stay healthy and productive—with increasing heat exposure. The two also deep dive into the science behind Goetz’s recent work on light-colored coats in Holstein Friesian cows. Using direct editing of embryos, Goetz and his team amplified naturally occurring coat mutation—which makes some cows lighter than others—to create lighter-colored cows in a single generation. These animals still retain their classic spots but with increased white coverage and a dilution of black spots to a light gray. Lighter gene-edited cows absorb a staggering 40% less solar radiation than their dominantly black counterparts, representing an important step forward for grass-fed dairy herds that spend most of their time outdoors. Listen in as Goetz sheds light on the potential applications of this technology in dairy herds, including his experience taking it to producers. He and Matt discuss the changing tides when it comes to farmer and consumer openness toward biotechnologies with the potential to help cows lead healthier, happier lives. An avid traveler, Goetz also shares his favorite perk of working in science and his advice for young scientists to embrace collaboration. 
Episode Thirteen Show Notes
Learn more about Goetz Laible’s work with AgResearch and connect with him on LinkedIn.
Save the date for the 51st International Embryo Technology Society Annual Conference (January 18–21, 2025, in Fort Worth, TX). 
Catch up on the papers discussed in the episode:
Production of light-coloured, low heat-absorbing Holstein Friesian cattle by precise embryo-mediated genome editing, Reproduction, Fertility and Development (2023)
Cytoplasmic injection of zygotes to genome edit naturally occurring sequence variants into bovine embryos, Frontiers in Genetics (2022) 
Embryo-mediated genome editing for accelerated genetic improvement of livestock, Frontiers of Agricultural Science and Engineering (2020)
Cattle with a precise, zygote-mediated deletion safely eliminate the major milk allergen beta-lactoglobulin, Scientific Reports (2018) 
Targeted microRNA expression in dairy cattle directs production of β-lactoglobulin-free, high-casein milk, Proceedings of the National Academy of Sciences (2012)

Embryo-Mediated Gene Editing, Coat Color, and Mitigating Herd Heat Absorption in a Warming Climate with Goetz Laible, PhD

Why does the dairy sector have such a good story to tell about environmental sustainability, and how can each of us be a better storyteller for the industry? Join us for a mega episode of Dairy Digressions to find out! Host Matt Lucy is joined by esteemed guest Frank Mitloehner, PhD, a professor and extension specialist in the Department of Animal Science at the University of California, Davis, and director of the UC Davis CLEAR Center. An agricultural engineer and air-quality expert, Frank explains exactly why today’s climate change is outside of normal climate patterns, outlines the three main gases responsible for the greenhouse gas effect (carbon dioxide, methane, and nitrous oxide), and illustrates how their increase leads to higher environmental temperatures. While we know that the energy sector, particularly carbon from fossil fuels, accounts for the majority of global emissions, agriculture and the methane from livestock play a critical role in moving the needle toward our shared net zero–emissions future. With a majority of American refrigerators containing animal-sourced foods, Frank is focused on how we can produce those foods while addressing environmental issues ranging from air quality and emissions to animal welfare, worker health and safety, and more. Using Frank’s home state of California as an example, the two discuss how agriculture is currently excelling in finding ways to turn methane from a liability into an asset; dairy farms are on track to achieve 40% or more methane reduction by 2030, reach climate neutrality, and sell credits to other sectors. Despite these incredible advancements, it can feel like the climate narrative around agriculture remains thorny. Frank explains why he established the CLEAR Center and his work—including a recent trip to speak at COP28—to not only advance the science around climate in agriculture but to break down misconceptions and help consumers and thought leaders better understand the importance of agriculture in sustainably nourishing the world. 
Episode Twelve Show Notes
Learn more about Frank Mitloehner’s work at the UC Davis CLEAR Center, read his blog posts, and connect with him on LinkedIn and X/Twitter. 
Catch up on the papers and the news articles discussed in the
episode:
Big oil distracts from their carbon footprint by tricking you to focus on yours, GHG Guru (2020)
New report: California is pioneering a pathway to significant dairy methane reduction, UC Davis CLEAR Center (2022) 
Sixth Assessment Report (AR6), Intergovernmental Panel on Climate Change (2023) 
Animal board invited review: Opportunities and challenges in using GWP* to report the impact of ruminant livestock on global temperature change, Animal (2023) 
Fifty years of environmental progress for United States dairy farms, Journal of Dairy Science (2024) 




Dairy’s Environmental Progress, Greenhouse Gas 101, and Key Outcomes from COP28 with Frank Mitloehner, PhD

We’re kicking off the new year—and our new season of Dairy Digressions—with a special guest, Pete Hansen, PhD, Distinguished Professor of Animal Sciences and L. E. “Red” Larson Professor at the University of Florida. Pete’s research focuses on embryo physiology and developing new management strategies for increasing dairy cattle fertility, particularly in the face of heat stress and a warming climate. A leader in embryology and early embryonic loss, Pete explains when embryos are most sensitive to heat stress and why—including the scientific tools we have for preventing these effects—from genetic selection to embryo transfer to management for cow health and the potential future of artificial embryos from stem cells. A longtime mentor to undergraduate and graduate students (don’t miss his paper on the topic!), Pete also lets listeners in on his teaching philosophy and shares tips for crafting a lab environment that fosters collaboration, hard work, and joy around science. 


Episode Eleven Show Notes
Learn more about Pete Hansen’s work at the University of Florida, and connect with him on LinkedIn and X/Twitter. 
Are you interested in learning more about the journal
loyalty program mentioned in the episode? Get all the details,
and sign up today! 
Catch up on the papers and the news article discussed on the
episode:
Reflections on a career as a graduate mentor—from baby steps at Wisconsin to today, Journal
of Animal Science (2023)
Stem cells used to model a two-week-old human embryo, Nature
News and Views (2023) 
Complete human day 14 post-implantation embryo models from naive ES cells, Nature
(2023) 
Pluripotent stem cell-derived model of the post-implantation
human embryo, Nature (2023)

Dairy Nutrition and Managing the Rumen Microbiome for Productivity and Sustainability with Jeff Firkins, PhD

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