Cattle Chat Podcast Summary

Episode: Beef-on-Dairy, Free Martin, Spring Pond Death
Host(s): BCI Cattle Chat Team (Brad, Bob, Scott, Dustin, Phillip)
Date: July 4, 2025

Episode Overview

This episode of Cattle Chat brings together veterinary professionals from the Beef Cattle Institute at Kansas State University to discuss key listener questions and timely topics in beef production. The main themes include the long-term impacts of pre-weaned calf nutrition (with a focus on bottle calves and calf ranches), the biology and management implications of free martins in cattle, and sudden cattle deaths near ponds, exploring whether blue-green algae, lightning, or other factors could be responsible.

Key Discussion Points & Insights

1. Pre-Weaned Calf Nutrition & Long-Term Health

(04:32-13:18)

• Knowledge Gaps in Research:
  • Most research focuses on the “hutch phase” (up to ~80–90 days in dairy calves). There’s little data following calves post-hutch to see long-term impacts.
    • “Most of the university research around nutrition on these calves looks at what we call the hutch phase... There’s been a lot of research done on how to formulate starter rations for these calves to get them off of milk at young ages… But we have very little research that follows them on past that stage.” — Phillip (04:40)
• Colostrum & Health:
  • Colostrum intake is pivotal for health outcomes. Calves that encounter health problems pre-weaning often continue to be disadvantaged.
    • “The ideal situation is a calf basically doesn’t have any bad days... colostrum intake can be associated with health.” — Bob (05:56)
• Butyrate & Rumen Development:
  • Butyrate, produced by rumen microbes digesting carbohydrates, is critical for the development of the rumen wall. Producers can promote butyrate via feed composition (adding digestible starches, fibers, or direct butyrate supplementation).
    • “Butyrate is the primary energy source for the rumen epithelium… so having a good production of butyrate in the rumen is critical for development.” — Phillip (06:40)
    • “One of the ways we do that is we provide much more highly digestible carbohydrates in that starter feed than what beef calves do with grass.” — Phillip (09:09)
• Starch in Starter Diets:
  • A moderate amount of starch (25–30% of diet) is needed, higher than what growing beef calves would receive, because dairy calves transition to solid feed faster.
    • “We want some starch. From what I’ve seen... talking 25 to 30% starch in that starter diet… quite a bit higher than our native beef calves.” — Phillip (08:21)
• Sulfur Tolerance in Young Calves:
  • There’s little published data on sulfur tolerance specific to very young calves. The generally accepted dietary range is about 0.35–0.45%, accounting for both feed and water contributions—especially important in areas with high-sulfur water or feed by-products like distillers grains.
    • “I don’t have a good answer because as far from I know is that most of the stuff that’s been done and published is with older feedlot cattle or even mature animals.” — Phillip (10:59)
    • “An important consideration is total diet is including water contributions… certain areas of the country are going to have a lot more sulfur in their ground water sources.” — Scott (11:45)

Notable Moment:

• Debunking the notion that a high-starch starter ration is automatically bad, given the accelerated rumen development in dairy calves.
  • “We’re giving them seven weeks to make that switch.” — Phillip (09:09)

2. Free Martinism in Cattle & Sexed Semen Technology

(13:50–18:05)

• Definition & Cause:
  • A free martin is a sterile heifer born as a twin to a bull calf, due to hormone transfer between fetuses early in gestation.
    • “A free Martin is a female calf born twin to a bull calf... hormones from the bull calf cross the placenta and affect the female tract so it doesn’t develop normally.” — Bob (13:50)
• Incidence & Sexed Semen:
  • Occurs in >90% of male-female twins. Using sexed semen reduces but does not eliminate the risk.
    • “Very few things... are 100%. So when we sort semen into X female straws and Y male straws, we’re about 90% accurate… Out of a hundred pregnancies, 10 would be the opposite sex of what I selected.” — Bob (15:08)
• Diagnosis & Management:
  • External clues include an abnormally long distance between anus and vulva, and a shallower vaginal vault; definitive diagnosis may require reproductive tract scoring. Free martins are almost always infertile.
    • “Usually there’s some clues externally—the distance between the anus and the vulva... she just doesn’t look quite right.” — Bob (17:15)
    • “Almost zero [chance she’ll breed]... very, very few things in biology are 100% but this is close.” — Bob (17:06)

3. Cattle Sudden Death Near Ponds: Blue-Green Algae, Lightning, or Other?

(18:08–23:31)

• Initial Steps & Differential Diagnosis:
  • Don’t presume the pond is to blame. Always involve a veterinarian and conduct a necropsy.
    • “First and foremost is probably get a veterinarian involved and do a post mortem exam.” — Scott (18:36)
• Blue-Green Algae (Cyanobacteria):
  • Toxic algae can look like a floating “scum” or spilled “green paint,” though colors can vary. Confirm via microscopic examination of a water sample; a visible green ring at the top of a standing sample is a quick field clue.
    • “The best description I could give is it looks like paint—that somebody just dumped green paint on the top of the surface.” — Scott (19:06)
    • “A pretty quick rudimentary test is if you take that sample... and you just set it on a flat surface for about a half an hour, most of those algae are buoyant… you’ll get this green ring at the very top.” — Scott (21:16)
• Lightning Strike:
  • Sudden death near a pond, especially after thunderstorms, could also be lightning. Necropsies may reveal little unless there are burns; often a diagnosis by exclusion based on recent weather and proximity to ponds or trees.
    • “Once in a while you'll see some lesions or something associated with, you know, a direct strike by lightning. But usually what happened is the lightning struck nearby and electrocuted the animal... so it's a little bit of a diagnosis by ruling everything else out.” — Bob (20:07)
• Precautions and Next Steps:
  • Blue-green algae can harm humans—use gloves, avoid inhalation, and submit labeled samples for analysis. If a toxic bloom is confirmed, keep cattle (and people) away until bloom subsides and, ideally, for about a week after the scum disappears.
    • “Some of those can be irritating dermally and some… can actually aerosolize and cause some shortness of breath, that kind of thing.” — Scott (21:16)
    • “Typical recommendations are prevent access until the bloom’s gone and maybe give it a week afterwards for a rough estimate.” — Scott (22:14)

Notable Moment:

• “The only consistent thing about [by-products] is they’re inconsistent.” — Scott (re: sulfur content in distillers grains) (12:32)

Memorable Quotes

• On research gaps in calf nutrition:

  • “Most of the university research around nutrition on these calves looks at what we call the hutch phase… But we have very little research that follows them on [from there].” — Phillip (04:40)

• On butyrate's importance:

  • “Butyrate is the primary energy source for the rumen epithelium... critical for development of rumen papillae and the absorptive ability and functioning of that rumen.” — Phillip (06:40)

• On free martins and twin pregnancies:

  • “A free Martin is a female calf born twin to a bull calf... some hormones from the bull that cross the placenta and affect the female tract so it doesn’t develop normally.” — Bob (13:50)

• On blue-green algae diagnosis:

  • “The best description I could give is it looks like paint—that somebody just dumped green paint on the top of the surface.” — Scott (19:06)

• On uncertainty in by-product feeds:

  • “The only consistent thing about them is they're inconsistent.” — Scott (12:32)

Timestamps for Key Segments

• 04:32 — Start of discussion on pre-weaned calf nutrition
• 06:40 — Butyrate and rumen development
• 08:21 — Starch in starter diets for calves
• 10:59 — Sulfur tolerance in young calves
• 13:50 — Free martinism explained
• 15:08 — Sexed semen accuracy and free martin risk
• 17:15 — Diagnosing a free martin
• 18:08 — Sudden cattle deaths and ponds: initial considerations
• 19:06 — What toxic blue-green algae looks like
• 20:07 — Lightning as a cause of sudden death
• 21:16 — Field test for blue-green algae & handling precautions
• 22:14 — Recommendations for managing toxic pond blooms

Closing Thoughts

This episode underscores the importance of continued research and vigilance in calf nutrition, the nuances of reproductive technology and congenital issues, and a practical, veterinarian-driven approach to diagnosing sudden deaths in herds—especially during challenging spring and summer months. Listener questions keep the show relevant and practical, providing real-world scenarios for expert analysis.

For more information, feedback, or questions, listeners are encouraged to contact the BCI Cattle Chat team at bciksu@edu.