Podcast Summary: Cattle Chat – Research Update: Liliana Rivas and Cow Efficiency

Podcast: Cattle Chat (Beef Cattle Institute, Kansas State University)
Episode: Research Update: Liliana Rivas and Cow Efficiency
Date: February 6, 2026
Host(s): Dr. Brad White, Dr. Bob Larson, Dr. Philip Lancaster, Dr. Dustin Pendell, Dr. Scott, Special Guest: Liliana Rivas

Episode Overview

This episode of Cattle Chat features a deep dive into the latest research at Kansas State University on two main topics:

1. Leaky gut in cattle, focusing on diagnosis and its implications, presented by grad student Liliana Rivas.
2. Cow efficiency modeling—what it is, how it’s measured, and how mathematical models compare to real-world results.

The discussion offers practical takeaways for beef producers and veterinarians, highlighting ongoing research needs and surprising findings in cattle nutrition and reproduction.

Key Discussion Points & Insights

1. Getting to Know Liliana Rivas (03:10–04:03)

• Liliana is a Colorado native who had no cattle experience until coming to Kansas State University.
• Progressed from working with dairy cows in her undergraduate studies to pursuing a master’s degree focused on cattle health and nutrition.
• Liliana appreciates learning to analyze scientific literature and real research data:

  “I feel like I know how to read scientific literature better. I’m working through a lot of data analysis, and it’s all pretty cool to be a part of.” (00:50)

2. Understanding Leaky Gut in Cattle (04:03–05:50)

• Technical term: Gastrointestinal permeability.
• Dr. Philip explains:

  “What we think is happening ... is that paracellular transport, so molecules going between cells in the GI tract, increases for whatever reason...the tight junctions between cells that keep stuff out ... are weakened, and that allows molecules and even bacteria to cross into the bloodstream.” (04:25)

• Suspected causes: Nutritional stress (feed restriction, high starch diets), heat stress, changes to the microbiome.
• Knowledge Gaps: It’s not clear how frequently leaky gut occurs, what all the causes are, or exactly how it impacts cattle health.

3. Potential Consequences for Cattle (06:34–07:27)

• Main concerns:
  • Bacteria entering the bloodstream.
  • Disruption of mineral uptake and possibly interference with feed-grade antibiotics.
• Dr. Scott’s perspective:

  “You shower the bloodstream with bacteria—that’s probably not good ... Some of the other like metal type things that we have fairly regulated uptake for could be disrupted ...” (06:48)

4. How is Leaky Gut Diagnosed? (07:27–08:08)

• No gold standard test.
• Common research methods:
  • Feeding indigestible sugars or minerals like chromium and measuring their presence in blood or urine.
• Dr. Brad summarizes:

  “So you feed them something that shouldn’t cross over ... If it shows up [in blood or urine] ... you go, ‘Ah, there’s leaky [gut].’” (07:46)

5. Liliana’s Research on Leaky Gut (08:08–11:22)

Research Design:

• Used two indigestible sugars, measured in blood at multiple time points over 36 hours to test permeability.
• Induced leaky gut via feed restriction:

  “We restricted their feed by quite a bit ... to 25% of that intake.” (09:11)

• Focused on yearling (ruminating) calves, ~600–700 lbs to build on previous research that primarily used pre-weaned calves.

Findings:

• Feed restriction reliably induced leaky gut in all animals.
• Both test sugars crossed into the blood, but one did so more consistently, suggesting a better tool for future research.
• Detectable sugar levels occurred between 3 and 36 hours after dosing.

"We found that both sugars were able to cross—one sugar more than the other, or more consistent than the other, which may be a better research tool for us moving forward." (10:20)

Practical Application:

• This method could allow producers/vets to test for leaky gut over a generous window (3–36 hours).
• Next steps: Broader studies, testing across different diets and older cows.

6. Broader Leaky Gut Impacts & Future Research (11:52–12:27)

• Potential connections between leaky gut and other cattle diseases (e.g., respiratory disease).
• Liliana’s work will expand to younger calves in the future.

7. Cow Efficiency: Definitions and Modeling (12:27–20:56)

What is Cow Efficiency? (12:27–13:53)

• Dustin: From an economic/production angle, efficiency = outputs relative to input use.
• Philip:

  “We used the same measure [as previous work]: pounds of calf weaned per pound of feed consumed per cow exposed to the bull.” (13:29)

Measurement Challenges (14:23–16:01)

• Measuring actual feed intake on pasture is extremely difficult—models must estimate intake.
• Used a nutrition model validated against a tightly controlled pen-feeding trial.

Model vs. Real World (16:03–17:24)

• Energy-restricted cows in reality lost more body weight, condition, and fertility than the models predicted.
• The model did not capture dramatic drops in reproductive performance seen in severe feed restriction.

“Our mathematical representation ... is not matching in the real world ... What that’s telling Bob and I, is that we’re missing something in the way we understand how energy restriction impacts reproductive performance of cows.” (16:03)

Why the Mismatch? (17:42–19:48)

• Models may underestimate both postpartum infertility and the depth of fertility impact caused by poor nutrition.
• Dr. Bob Larson on model limitations and practical animal husbandry:

  “I love using math to describe biology, but I understand there are limits...There is still the animal husbandry, the art side of managing cows... So putting together the art and the science is really still very important.” (18:47)

Big vs. Small Cows (19:48–20:37)

• Larger cows aren’t necessarily less efficient; efficiency varies within herds.
• Identifying the most efficient individual cows is tough since it requires impractical intake tracking in real-world ranches.

8. Take-Home Messages for Producers (20:37–22:05)

• Monitor cow body condition, especially before calving, to support fertility and efficiency.
• Math and models can guide but have limits:

  “Our basic understanding of what it takes to be a good efficient cow is ... have her in good body condition going into calving, make sure nutrition is adequate ... as long as when things go well, we’re pretty happy with how that goes.” (20:56)

• Severe undernutrition has a greater negative effect on reproduction than models may predict; hands-on management remains crucial.

Notable Quotes & Memorable Moments

• On daring Olympic sports:

  “I’m going head first, man. Full send.” – Dr. Scott (01:47) “I think I’ll go head first, cuz, I mean, you get injured, you get injured.” – Liliana Rivas (02:52)

• On leaky gut’s unknowns:

  “I don’t know if guts didn’t used to leak and now they do, or we’ve ... gotten some evidence that...might affect whole body health.” – Dr. Bob Larson (05:17) “There’s so many unknowns right now about this leaky gut phenomenon that we don’t have a good way to understand it or to prevent it.” – Dr. Philip Lancaster (05:50)

• On science and practicality:

  “Sometimes I overestimate how good my math is describing biology...” – Dr. Bob Larson (18:46) “There is still the animal husbandry, the art side of managing cows... So putting together the art and the science is really still very important.” (18:47)

Key Timestamps

• 00:50: Liliana on her education and research outlook
• 04:25: Dr. Philip explains leaky gut (GI permeability)
• 06:48: Dr. Scott discusses leaky gut consequences
• 07:46: Blood/urine testing method for leaky gut
• 08:11–11:22: Liliana details her experiment and findings
• 13:29: Philip defines cow efficiency metric
• 16:03: Model vs. real-world findings in cow efficiency
• 18:46: Importance of blending math with animal husbandry
• 20:56: Practical takeaways on managing body condition and nutrition

Takeaways & Closing Thoughts

• Ongoing research like Liliana’s is refining tools and understanding for better cattle health management, especially for conditions like leaky gut with complex, underexplored impacts.
• Efficiency modeling offers valuable guidance, but on-the-ground observation and management are irreplaceable, particularly in guarding against the reproductive costs of poor body condition.
• This episode strikes a balance between scientific exploration and real-world insight, highlighting the value of both for beef producers and veterinarians.

For further questions or topic requests, listeners are encouraged to reach out to the BCI team via email or social media.