Cattle Chat Podcast Summary

Episode Date: December 5, 2025
Host: BCI Cattle Chat Team
Guest: Dr. Cassandra Olds, Entomologist
Main Themes: Theileria—Transmission and Management, Fly and Tick Biology, and Winter Feeding Strategies

Episode Overview

In this episode, the BCI Cattle Chat crew welcomes Dr. Cassandra Olds, an entomologist specializing in livestock disease vectors, to discuss Theileria—an emerging parasitic disease in cattle—its transmission, clinical presentation, and management. The latter portion of the episode shifts to practical advice on winter feed planning and strategies to minimize resource loss and optimize herd health.

Key Discussion Points and Insights

1. Introductions and Lighthearted Opening

Timestamps: [00:05]–[03:55]

• The hosts and Dr. Olds introduce themselves.
• The group shares humorous takes on training montages inspired by the “Eye of the Tiger” theme, relating to procrastination, holiday eating, and puppy wrangling.
• Notable Moment:
  • Dr. Olds: “I may not ever...I'm really good at postponing the exercise.” [03:46]
  • Dr. Olds shares a friend’s advice: “You're not procrastinating, you're just not ready to do it yet.” [03:55]
• Tone: Friendly, light-hearted, relatable.

2. Theileria: Characterization and Transmission

Timestamps: [04:09]–[10:56]

What is Theileria?

• Dr. Olds explains that Theileria is a single-celled eukaryotic parasite, related to malaria, transmitted primarily by ticks.
• Quote:
  • “Its cousin is malaria. And I always say, you know, malaria has been around since mummies in ancient Egypt...So notoriously, these parasites are difficult to control.” — Dr. Olds [04:31]

Modes of Transmission

• Primary: Ticks—the most effective amplifier as the parasite multiplies inside tick salivary glands before infecting cattle.
  • “So you don't need a lot of ticks to get transmission.” — Dr. Olds [05:50]
• Other Vectors:
  • Sucking lice—can transmit, especially among calves.
  • Stable flies—emerging evidence shows flies can mechanically transmit Theileria, prompting ongoing research.
    • “We actually caught stable flies and we chopped the heads...and we found the pathogen in the heads...” [06:36]
    • “Flies are doing a pretty good job of transmitting it.” [07:15]
• Mechanical Transmission: Blood-contaminated equipment—needles, castration, dehorning tools—can also spread the parasite.
  • “Needles definitely. And so we are really, really recommending single needle use.” [07:51]
• Placental transmission: Rare, but possible (~2%).

Amplification Differences: Ticks vs. Flies

• Ticks: Biological amplification—parasite multiplies within tick, causing higher doses and more severe disease.
• Flies: Mechanical, not biological; flies just transfer contaminated blood.
  • “So they're just picking up and moving it...from animal A to animal B.” [08:38]

Stable Fly Biology and Spread

• Population numbers can explode rapidly with the right weather conditions—warm and humid.
  • “Next week you've got 100, and then next week you've got a thousand.” — Dr. Olds [10:56]
• Unlike ticks, fly populations are closely tied to immediate weather.

3. Theileria in Cattle: Clinical Signs and Diagnosis

Timestamps: [10:56]–[16:43]

Clinical Presentation

• Young Calves: Often present like pneumonia (“pneumonia that doesn't respond to treatments”), rapid shallow breathing, depression, sudden loss of appetite.
  • “The hallmark...is that cattle go off feed very quick.” — Dr. Olds [12:43]
• Mature Animals: Looks more like anaplasmosis initially (exercise intolerance, sluggishness, weight loss, fever), followed later by pronounced anemia.
  • Disease can be worse and appear faster with higher infective dose (tick-borne).
• Naïve/Introduced Animals: Most severe cases seen in non-exposed cattle brought into endemic herds or pastures.

Misdiagnosis and True Prevalence

• “...100% infection rates [in long-resident herds], zero history of disease.” — Dr. Olds [14:29]
• Disease often misdiagnosed as anaplasmosis due to overlap in symptoms, particularly in endemic areas.
  • “We may have seen disease for years and misdiagnosed it.” — Brad White [15:39]

Diagnosis

• Blood PCR tests through state diagnostic labs; increasingly affordable.
  • “Even if you don't have disease, test your herd to find out if you have it.” — Dr. Olds [16:15]

Implications for Herd Management

• Incidence of severe disease relates to exposure status and immune experience; endemic herds can be nearly 100% positive with no clinical issues.
• Emphasis on managing risk—don’t unnecessarily cull valuable, asymptomatic positive animals.

4. Control and Management Challenges

Timestamps: [16:43]–[16:49]

• Tick and fly control techniques exist, but are imperfect and typically not sufficient alone.
  • “We don't have a lot of control techniques for tick [and] flies...this is a disease that we're going to have to live with.” — Brad White [16:49]

5. Winter Feeding Strategies and Fly Control

Timestamps: [16:49]–[25:58]

Planning Winter Feeding

• Even in strong markets, controlling feed costs and minimizing waste is essential.
• Best Practices:
  • Remove old, wasted hay from feeding and calving grounds to reduce fly breeding sites.
    • “Unless you remove that breeding site, you can plant as much pesticide as you want...you'll never impact the population.” — Dr. Olds [18:41]
    • “The stable fly loves old hay.” — Bob [18:17]
  • Good area hygiene helps delay population surges of stable and house flies.

Hay Calculation and Inventory Tips

• Importance of accurately estimating cow and bale weights.
• Calculate daily hay needs:
  • Cow body weight x (2–2.3)% = daily forage intake (dry matter basis)
  • Add ~10% for wastage and adjust based on actual disappearance.
    • “So it's not just how many bales do I need for the winter, it's how many bales do I need for the winter, and then I get the first month in, does that seem about right or not, and then I adjust on the fly.” — Brad White [25:58]

Forage Testing

• Underutilized; essential for understanding quality, better ration formulation.
  • “Forage tests are pretty inexpensive for the information you get.” — Jason [21:01]
  • Sample 10–20% of the lot for best representation.

Monitoring Intake and Preventing Body Condition Loss

• Track actual hay disappearance (bales fed vs. expected).
• Monitor, adjust, and account for quality, waste, cow weights, and additional animals.
• Caution: Lower quality hay leads to lower intake and higher waste, complicating feed management.
  • “The better quality hay is...the more rapidly the cows eat it...poorer quality hay, they're gonna eat less and they'll probably waste more.” — Bob [24:08]

Notable Quotes and Memorable Moments

• Dr. Cassandra Olds:
  • “You're not procrastinating, you're just not ready to do it yet.” [03:55]
  • “Its cousin is malaria...these parasites are difficult to control.” [04:31]
  • “Unless you remove that breeding site, you can plant as much pesticide as you want...you'll never impact the population.” [18:41]
• Brad White:
  • “This is a disease that we're going to have to live with over time.” [16:49]
  • “So it's not just how many bales do I need for the winter...does that seem about right or not, and then I adjust on the fly.” [25:58]

Key Timestamps for Important Segments

• 03:55 – Dr. Olds on procrastination and exercise
• 04:31 – Introduction to Theileria: biology, importance
• 05:27 – Transmission: ticks, lice, flies, and more
• 07:51 – On-farm transmission via needles and equipment
• 08:38 – Mechanical vs. biological transmission by flies
• 10:04 – Stable fly population dynamics
• 12:43 – Clinical presentation in calves: hallmark signs
• 14:29 – Herd infection: naïve vs. endemic population risk
• 16:15 – Diagnostic testing and management implications
• 18:17 – 19:25 – Stable flies, breeding, and feed area management
• 21:01 – Value of hay/forage testing
• 24:08 – Monitoring hay disappearance and waste

Summary Takeaways

• Theileria is a challenging, increasingly widespread tick-borne parasitic disease with alternative transmission routes involving flies and mechanical means.
• Clinical signs can easily be misdiagnosed; comprehensive diagnostics and understanding herd infection status are crucial for management.
• Control of vectors is difficult; focus shifts to managing risk, herd immunity, and prudent practices such as single-needle use and feed area hygiene.
• Well-planned winter feeding, accurate estimation, and ongoing monitoring prevent resource waste and animal performance loss.
• Fly control starts with sanitation—removal of decaying hay and manure prevents explosive stable fly populations.

This episode blends expert insight with actionable advice for both disease and feed management, reflecting the realities producers face heading into winter.