Key Takeaways
- Zeolite worked at a lower dose. About 300 grams per day of zeolite before calving appeared to work as well as the 500 grams per day used in earlier research, and it cost less.
- Most zeolite-fed cows kept normal calcium. About 90% of cows fed zeolite before calving were eucalcemic.
- The study tested calcidiol with two strategies. Researchers studied 92 multiparous Holstein cows. They tested whether adding calcidiol to a negative DCAD diet or to zeolite improved mineral metabolism, calcium regulation, and milk performance.
- Cows were grouped by how well their calcium recovered. Dyscalcemic cows still had blood calcium below 2.2 millimoles per liter on day four after calving.
- Zeolite is easier to manage. Negative DCAD diets require urine pH monitoring and forage mineral analysis.
- Dose depends on the diet. The right zeolite amount will likely depend on the diet’s mineral balance, especially how much phosphorus it contains.
- Both approaches are viable. Negative DCAD diets still work well, and many herds and nutritionists have years of experience with them.
Episode 228: Prepartum Calcium Strategy, Calcidiol, and Cow Performance
Timestamps:
This bonus episode of the Real Science Exchange Podcast was recorded live at the American Dairy Science Association (ADSA) 2026 Annual Meeting. It covers nutritional strategies that support calcium regulation and mineral metabolism as dairy cows move into early lactation. Host Scott Sorrell, Director of Global Marketing at Balchem, talks with Dr. Tom Overton of Cornell University and Dr. Francisco Somare of Progressive Dairy Solutions.
From Argentina to Cornell
To start, Dr. Overton talks about his work at Cornell University. He also explains how Dr. Somare came to Cornell from Argentina on a Fulbright scholarship after working in the feed industry and teaching. Dr. Somare then introduces the poster he’s presenting at the meeting. (00:00 – 01:28)
Study Design: Zeolite, Negative DCAD, and Calcidiol
Dr. Somare explains that the study tested whether combining zeolite and calcidiol could improve mineral metabolism, calcium regulation, and milk performance in early lactation. Researchers enrolled 92 multiparous Holstein cows in four groups. Two groups were fed a negative DCAD diet and two were fed zeolite, and one group under each strategy also received calcidiol. The zeolite groups were fed about 300 grams. (02:34 – 04:13)
Results: Dyscalcemic vs. Eucalcemic Cows
After the study, cows were classified as dyscalcemic or eucalcemic based on how well their calcium recovered. Dyscalcemic cows were still below 2.2 millimoles per liter on day four. Dr. Overton points out that earlier research used 500 grams of zeolite per day. The 300-gram dose tested here cost less and appeared to work just as well. About 90% of cows fed zeolite before calving were eucalcemic. (04:14 – 06:27)
Practical Application on the Farm
Dr. Somare describes zeolite as easier to manage than negative DCAD diets, which require urine pH monitoring and forage mineral analysis. On dosing, he says the right amount will probably depend on the diet’s mineral balance, but the study saw good results at 300 grams. (06:28 – 08:09)
Two Viable Prepartum Options
Dr. Overton adds that recommendations may go up or down depending on the grams of phosphorus in the diet. He also stresses that negative DCAD diets still work well and that many herds and nutritionists have years of experience with them. He sees both approaches as viable options. (09:01 – End)
Listen, Subscribe, and Share
If you enjoyed this episode, subscribe to the Real Science Exchange and share it with your colleagues in the dairy industry. That way, they can join the conversation at our virtual pub table.
Continue learning from leading researchers and dairy industry experts by registering for an upcoming Real Science Lecture Series webinar.
And don’t forget your Real Science Exchange T-shirt! Screenshot your rating, review, or subscription, then email the image to anh.marketing@balchem.com along with your shirt size and mailing address.
FAQ
What is calcidiol, and why use it in transition cows?
How much zeolite was fed in the study?
What is the difference between dyscalcemic and eucalcemic cows?
Is zeolite easier to manage than a negative DCAD diet?
Are negative DCAD diets still recommended?
Full Transcript
Welcome and Guest Backgrounds
Introduction and Meet the Guests (0:00)
Scott Sorrell: Good evening, everyone, and welcome to the Real Science Exchange, the podcast where leading scientists and industry professionals meet over a few drinks to discuss the latest ideas and trends in animal nutrition. Today, I’m here with Dr. Tom Overton and Francisco Somare from Cornell University. Tom, you’re still at Cornell. Francisco has graduated and is now working for PDS down in Argentina, so congratulations on that. Fine company. I know a lot of those guys.
Dr. Tom Overton and Francisco Somare’s Background (0:39)
Scott Sorrell: Tom, I’d like to start with you. Give me a little background on yourself, and then tell me how you met Francisco.
Dr. Tom Overton: Yeah, Scott. As you know, I’ve been at Cornell a long time, combining research, extension, teaching, and some administrative responsibilities over time. Francisco came out of the blue. He applied for a Fulbright scholarship in Argentina and ended up coming to Cornell on it. It was a great opportunity for him. He already had some experience in the feed industry and with teaching down there, but he decided he wanted to do a master’s to further his education and elevate his opportunities in Argentina. We’re really glad we brought him on.
Scott Sorrell: Outstanding. And you’re giving a poster here?
Francisco Somare: Yes, I have a poster tomorrow morning.
Scott Sorrell: Tomorrow morning. Great. Tell me all about it: what the hypothesis was, how you set it up, and then we’ll get into the results.
Ad Read: ReaShure Precision Release Choline
The economics of feeding ReaShure Precision Release Choline: ReaShure is fed during the transition period. Because it’s fed for such a short time, it costs just $15 per cow, and the benefits keep generating income throughout the year. Cows fed ReaShure produced 5 lbs more colostrum, which pays for your ReaShure investment on the very first day of lactation. Cows fed ReaShure also produce 5 lbs more milk per day, every day. That means after the first day, every day is payday. Invest in ReaShure during the transition period and recoup your investment on the very first day of lactation. After that, you got it: payday.
Study Overview and Research Findings
Study Hypothesis and Design (2:34)
Francisco Somare: Our hypothesis was that combining zeolite and calcidiol could have a positive impact on mineral metabolism, calcium regulation, and milk yield, meaning milk performance during early lactation.
Scott Sorrell: Okay.
Francisco Somare: For this study, we enrolled 92 multiparous Holstein cows in four groups. Two groups were fed a negative DCAD diet, and the other two were fed zeolite. Within each strategy, one group of cows was fed calcidiol and the other was not. Those were our four groups.
The zeolite approach was to feed around 300 grams of zeolite. Zeolite is an aluminum silicate that has normally been known as a calcium binder, but it is also a very strong phosphorus binder.
Scott Sorrell: Okay.
Francisco Somare: More recent research has shown that it strongly binds phosphorus.
Scott Sorrell: Very well. And what were the results?
Results and Dyscalcemia Reduction (4:14)
Francisco Somare: The results showed that zeolite helped reduce dyscalcemia in cows. We took blood samples on days [−14], −7, and −3 before calving, on each of the first four days after calving, and on days 7 and 14. Then we classified the cows after the fact as dyscalcemic or eucalcemic, using McArt’s categorization. Eucalcemic cows had already recovered proper calcium concentrations by day four. Dyscalcemic cows still had blood calcium concentrations below 2.2 millimoles per liter on day four.
Scott Sorrell: Tom, any surprises in the results?
Dr. Tom Overton: I don’t know about surprises. One thing about Francisco’s study is that it’s really the first one to feed a lower dose of zeolite, which is more commonly done now in the industry. In our previous work, and in work at Wisconsin, they fed 500 grams per day, which was the recommendation at that time. I don’t know all the prices, but 300 grams is certainly a lot more economical, and it seems to be just as effective. That’s a real gain from this study. The other thing is that Francisco had very few cows, especially on the zeolite treatments, that were still dyscalcemic. So it was very effective.
Francisco Somare: Yes, around 90% of the cows fed zeolite in the prepartum period were eucalcemic. That’s a very big difference compared with the negative DCAD group.
Practical Advice for Nutritionists (6:28)
Scott Sorrell: Any practical advice for nutritionists out there looking to use this product?
Francisco Somare: I think that’s a very important point. In the industry, we’re looking for strategies that are low-management, easy to put into practice, and deliver good results. Zeolite is one of those strategies. If you implement it properly, you’ll get very good results. We know the negative DCAD approach has other requirements. You need to monitor urine pH constantly, and you need to analyze your forages for minerals constantly. The zeolite strategy is, I would say, a low-management approach. It helps farmers who may not have an intensive way of controlling or monitoring these things.
Scott Sorrell: Do you think 300 grams is the sweet spot for dosing, or will it depend on the herd?
Francisco Somare: It will probably depend on the mineral balance of the diet.
Scott Sorrell: Okay.
Francisco Somare: But we consider 300 grams to be fine. As Tom said, earlier research used higher inclusion rates, but we achieved good results with 300 grams.
Scott Sorrell: Good. Tom, anything else?
Ad Read: KeyShure Plus Chelated Minerals
Welcome to the next generation in chelated minerals. Introducing new KeyShure Plus amino acid chelated minerals from Balchem. KeyShure Plus delivers a higher concentration of mineral with a superior amino acid profile. The higher mineral content adds formulation flexibility, opening up space in the ration, and it also reduces the carbon footprint. The superior amino acid profile delivers 28% protein from microbial biomass. The KeyShure Plus line also offers a granulated form for improved handling and reduced dust. Visit balchem.com to see how new KeyShure Plus can deliver the added benefits you need to improve performance and reduce manufacturing hurdles.
Diet Strategies, New Initiatives, and Closing Remarks
Upcoming Spanish Webinar Series Announcement (9:01)
Dr. Tom Overton: The recommendations from both companies marketing these products have been tied to grams of phosphorus in the diet. So the dose will go up or down a little depending on how many grams of phosphorus are in the diet. That seems like a rational approach to me. DCAD diets still work great, too. Lots of herds and lots of nutritionists have plenty of experience with those diets. We see both as viable options.
Scott Sorrell: Good stuff. Francisco, I wish you the best of luck down in Argentina as you embark on your career. I don’t know if you know this, but we run a webinar series in addition to our podcast, and we’re about to introduce a Spanish webinar series with all Spanish-speaking professors. So be on the lookout for that.
Francisco Somare: Okay, great.
Scott Sorrell: Good stuff. All right, thank you.
Podcast Outro and Viewer Information (10:13)
Francisco Somare: Thank you, and thanks to the audience out there.
Scott Sorrell: You bet. Thank you for joining us as well. I hope you learned something, I hope you had some fun, and I hope to see you next time here on the Real Science Exchange, where it’s always happy hour and you’re always among friends.
Announcer: We’d love to hear your comments or ideas for topics and guests. Please email us at anh.marketing@balchem.com with any suggestions, and we’ll work hard to add them to the schedule. Don’t forget to leave a five-star rating on your way out.
You can request your Real Science Exchange t-shirt in just a few easy steps. Like or subscribe to the Real Science Exchange, then send us a screenshot along with your address and t-shirt size at anh.marketing@balchem.com.
Balchem’s Real Science Lecture Series of webinars takes place on the first Tuesday of every month and covers the top research and nutrition topics that will impact your business. We also include small ruminant, monogastric, and companion animal topics throughout the year. Visit balchem.com/realscience to see upcoming topics and register for future webinars. You can also access past webinars and search for the topics most important to you.
