Michael Steele, PhD, and his lab colleagues are asking questions and offering answers for all of you calf raisers. We were happy to sponsor Dr. Steele’s webinar addressing new developments in calf nutrition. Listen as he pinpoints common practices ripe for reevaluation and where to challenge the status quo. His lab is passionate about studying early life programming. They believe you have tremendous opportunities to raise healthier calves by fine-tuning nutrition to enhance both performance and health. You’ll hear about the research behind calf-rearing practices surrounding colostrum feeding, milk composition, feeding planes and weaning nutrition. We hope you enjoy New Developments in Calf Nutrition: Challenging the Dogma.
Research confirms X-Zelit® improves blood calcium concentrations, plus offers other benefits for pre-fresh dairy cows
In a recent study done at the University of Wisconsin-Madison by Frizzarini et al. (2024)*, researchers compared three close-up diets and their implications on blood calcium and performance. The three diets included one diet with X-Zelit, one with negative dietary cation-anion difference (-DCAD), and one with a positive DCAD (control).
The study, which resulted in two publications published in the Journal of Dairy Science, showed that cows fed the diet with X-Zelit had higher blood calcium concentrations and lower blood phosphorus concentrations during the transition period relative to the other treatments. In addition, cows fed X-Zelit had higher colostral IgG concentrations, plus cows in their third or greater lactation fed X-Zelit produced the most milk.
X-Zelit is a dietary phosphorus binder that naturally stimulates a cow to mobilize her calcium reserves for effective milk fever prevention. This novel approach capitalizes on manipulating phosphorus homeostasis, rather than calcium homeostasis. X-Zelit should be fed 14 to 21 days pre-fresh to prevent milk fever and subclinical hypocalcemia.
“Despite the vast improvements made in the industry to manage milk fever, subclinical hypocalcemia and “milk fever breaks” remain a challenge on dairy operations. This challenge has resulted in continuing research of pre-fresh nutrition strategies to mitigate clinical and subclinical hypocalcemia,” says Dr. Meghan Connelly, Protekta dairy research and technical services.
The University of Wisconsin study included 121 multiparous Holstein cows, blocked by lactation number and expected due date. Cows were randomly assigned to one of the three prepartum diets: control (+190 mEq/kg; n = 40), -DCAD (−65 mEq/kg; n = 41), or the control diet supplemented with X-Zelit (synthetic zeolite A; +278 mEq/kg, fed at 3.3% DM, 500 g/day; n = 40).
In Part 1 of the study, researchers evaluated the effects of the three diets on peri-partal mineral metabolism. Some of the mineral metabolism metrics Dr. Frizzarini and colleagues analyzed were blood calcium, blood phosphorus, and fecal phosphorus. The results showed that cows fed X-Zelit exhibited the highest blood calcium concentrations prepartum and during the first few days following calving relative to cows fed -DCAD or control diets.
Also, cows fed the diet with X-Zelit had lower blood phosphorus concentrations relative to all other treatments, which is consistent with previously published research results. In addition, these cows had decreased salivary phosphorus concentrations and increased fecal water extractable phosphate, collectively suggesting that feeding X-Zelit induces a mild hypophosphatemia.
In Part 2, the research team assessed the effects of feeding the same three close-up diets (X-Zelit, -DCAD, and the control diet) on dry matter intake (DMI), energy metabolism, and colostrum and milk production. In this companion paper, researchers measured daily prepartum DMI, daily rumination, colostrum quality and quantity, daily milk production, and supplemental blood work to evaluate energy metabolism.
The results showed that feeding a diet with X-Zelit reduced DMI and rumination prepartum compared to -DCAD and control diets, but no differences were observed in rumination postpartum. Despite the prepartum decrease in DMI and rumination in X-Zelit-fed cows, blood glucose, β-hydroxybutyrate (BHB) concentrations, and body fat mobilization postpartum were not different between treatments.
After analyzing colostrum samples, researchers determined that yield and BRIX score did not differ between dietary treatments; however, colostrum collected from cows fed X-Zelit had the highest IgG concentrations (91.10 ± 2.63 mg/mL for X-Zelit, 78.00 for control, and 78.90 for -DCAD). Results also showed that mature cows (third or greater lactation) fed X-Zelit had the highest milk production (51.0 ± 1.1 kg) during the first 49 days in milk compared to cows fed -DCAD or control diets.
“Overall, these results support that the improvement in blood calcium concentrations pre and postpartum from feeding X-Zelit is most likely regulated by a dietary phosphorus restriction,” said Dr. Connelly. “This research helps further validate the role that dietary phosphorus plays in hypocalcemia and corroborates the results nutritionists and producers are seeing on farms. X-Zelit poses an intriguing option for close-up cows as this mechanism appears to be independent of DCAD, which means the need to source low-potassium forages is reduced.
Consequently, the pre-fresh diet has a lot more forage flexibility and you can include homegrown forages higher in potassium.”
For more details, Feedstuffs highlighted the 2-part study in a feature story, plus Hoard’s and Bovine Veterinarian also covered the research.
References:
J Dairy Sci. (March 13, 2024) Mechanisms by which feeding synthetic zeolite A and a dietary cation-anion difference diets impact mineral metabolism in multiparous Holstein cows: Part 1 https://www.journalofdairyscience.org/article/S0022-0302(24)00546-0/fulltext
J Dairy Sci. (March 13, 2024) Mechanisms by which feeding synthetic zeolite A and a dietary cation-anion difference diets impact feed intake, energy metabolism and milk performance: Part 2 https://www.journalofdairyscience.org/article/S0022-0302(24)00547-2/fulltext
The evolution of milk fever mitigation
Rod Martin knows how efforts to mitigate milk fever have evolved over the years. He shared his decades of experiences in a recent Dairy Herd Management article and offered advice for the future.
Rod, a Protekta dairy nutritionist with more than 35 years of experience and unparalleled insights into managing hypocalcemia, says that back in the ‘80s the focus was on minimizing dietary calcium levels to address milk fever. But the daily calcium limits suggested by the research were not practical in the field.
In the early ‘90s, the correlation between high potassium diets and increased milk fever rates was discovered. Consequently, producers and nutritionists quickly adapted low-potassium diets utilizing forages such as grass hay and corn silage. As hypocalcemia research continued to advance through the next two decades, negative dietary cation-anion difference (DCAD) diets evolved. They not only incorporated potassium but also added sodium, chloride and sulfur to the dietary analysis.
Fast forward to the 2020s. Milk fever and subclinical hypocalcemia mitigation is focused on dietary phosphorus and practical strategies to minimize daily phosphorus intake.
All this progress over the years has led to a low incidence of clinical milk fever, but subclinical hypocalcemia is still unacceptably high. To continue on the right path to controlling this metabolic disorder, more attention needs to be paid to excess phosphorus, Rod says.
Read the full story about the evolution of milk fever mitigation in Dairy Herd Management.
After that, read our summary of the science behind the role of dietary phosphorus in improving blood calcium and preventing hypocalcemia. It details a recent presentation by Pat Hoffman, Professor Emeritus at the University of Wisconsin.
Rod Martin’s article first appeared in Dairy Herd Management. A presentation on the science behind the role of dietary phosphorus in improving blood calcium and preventing hypocalcemia was given by Pat Hoffman, Professor Emeritus, University of Wisconsin.
Dairy Global: A cost-effective approach to stamping out milk fever
Milk fever is still a common dairy cow health issue around the world, but the use of new preventative products, especially synthetic zeolite, is now turning the tide thanks to US research.
Zeolite is a specific family of ‘hydrated aluminosilicate’ minerals that can be produced in synthetic form and is commercially available to feed to pre-fresh dairy cows.
“We are still seeing milk fever on dairy farms in Wisconsin and beyond,” says Patrick Hoffman, Professor Emeritus at the University of Wisconsin-Madison. “However, at this point in time, we now have an alternative way of preventing milk fever and subclinical hypocalcemia by feeding synthetic zeolite 2-3 weeks before calving. As its use spreads, we should see a reduced incidence of hypocalcemia. Zeolite is a very interesting entry into the milk fever prevention market.”
Hoffman notes that in the US and Canada in particular, knowledge about this product is already at a high level. “Most dairy nutrition consultants are aware of feeding zeolite to pre-fresh cows and are working with it to some degree,” he says. “Adoption has happened relatively quickly. Feeding zeolite to prevent milk fever started with a group of researchers in Europe experimenting with natural and synthetic zeolite about 20 years ago. About a decade ago zeolite was introduced in Canada and then into the US.”
Knowledge building
Researchers have known for a long time that feeding excessive levels of phosphorus (P) pre-calving was causing an increase in milk fever (calcium, CA, deficiency) at calving. However, for many years the reasons for this observation were unclear. Scientists now also understand that a peptide hormone active in bone tissue (called fibroblast growth factor 23) can regulate bone resorption of Ca and P (and urinary retention of P).
“About 20 years ago in Europe, they observed that feeding synthetic zeolite before calving elevated levels of blood Ca at calving,” says Hoffman. “They thought zeolite was directly working to cause the release of Ca from the bone (mobilisation) and improved intestinal absorption of Ca before calving, but that wasn’t exactly correct.”
That early research (and research since) has also shown that feeding zeolite before calving consistently reduces blood P levels, which induces bone mobilisation of Ca and P.
However, recently a University of Wisconsin-Madison team led by Dr Laura Hernandez figured out how zeolite was affecting the binding of P and not Ca per se. In their study, feeding zeolite to pre-fresh cows decreased blood and salivary P levels and increased faecal excretion of P. The cows responded to the lower blood P levels by mobilising bone.
These insights into P metabolism, says Hoffman, have made it easier to figure out how to use zeolite and balance the diet of a pre-fresh cow.
Other ways of mitigating milk fever
The team at the University of Wisconsin-Madison continues to study zeolite, but Hoffman says Hernandez and her colleagues have also been studying a compound called 5-HTP, a form of the amino acid tryptophan.
“They’ve discovered that the mammary gland itself can send signals to the rest of the body that it is in need of calcium,” Hoffman explains. “A supplement form of 5-HTP is now being commercialised and it’s very exciting. The team speculates that it may work in concert with zeolite, but that needs to be studied. Whatever is simplest and most effective at the farm level will be implemented on farms.”
Researchers are also testing the supplementation of a plant called Solanum glaucophyllum, which contains the metabolically-active form of Vitamin D, D3. Giving small amounts of this plant in a bolus has been shown to increase blood Ca levels, but Hoffman says that form of application may be labour-intensive and so commercialisation of another format may be a better way forward. Still, other researchers are working on other products that increase Ca absorption from the intestine, such as difructose anhydride.
Zeolite use
Preventing milk fever around the world through giving synthetic zeolite will require education, says Hoffman. “We need to build an infrastructure of nutritionists, veterinarians and farmers who understand the mechanism is new and different.”
He explains that when zeolite is fed, blood P values are going to decrease at calving, which is what needs to happen, and after calving blood P levels will rise quickly to 4 to 6 mg per decilitre (within 24-48 hours).
“Almost all dairy cows experience a transient phase in which blood P decreases at calving then increases quickly after calving,” says Hoffman. “It’s nothing new, but feeding zeolite induces this earlier. So it’s a paradigm shift in thinking about how blood P levels influence milk fever.”
Zeolite should also be fed at the right amount and for the right length of time. Because zeolite binds P, feeding it for too long might cause a P depletion. “Zeolite is fast-acting and is needed only for about 2 weeks, at least a week before calving,” Hoffman explains, “but since we don’t know exactly when calving will occur, we can start 2-3 weeks before.” Zeolite must also be mixed properly into the diet.
Another benefit to feeding zeolite before calving is that the cost is reasonably comparable to other milk fever prevention programs.
Hoffman explains that by feeding zeolite, farmers have to worry less about excess potassium going into the cow (and don’t have to monitor urine pH). This means farmers can feed their own higher-quality forages (alfalfa silage or grass silage) containing more protein and potassium. The need for purchasing low-potassium forages is avoided, protein supplementation costs may go down and that helps pay for the zeolite.
Hoffman adds that many dairy farmers who use zeolite also report that they don’t use as many calcium boluses, which also saves costs.
However, feeding synthetic zeolite is difficult to use in a 1-group dry cow situation, if cows are in the pre-fresh pen for long periods of time (greater than 28 days) and in overcrowded pre-fresh pens.
Worldwide use
Used correctly, zeolite represents a significant advancement in the prevention of milk fever.
Hoffman notes that Ca deficiencies at calving have many negative effects on cow performance, in addition to costing money and requiring more labour. While the second phase is easy to recognise due to clear symptoms, the consequences of early calcium deficiency are not easily detectable and can often be underestimated. In addition, cows that suffer from Ca deficiency have been shown to be more susceptible to other diseases.
This article was written by Treena Hein and first appeared in Dairy Global on Sept. 7, 2023.
Dietary Phosphorus Implications in Transition Cows
Dietary management strategies to improve blood calcium and reduce the risk of milk fever in dairy cows has been extensively studied over the decades. While research has looked at products, work has also focused on evaluating various levels of individual macro-minerals in pre-fresh diets and the impact on a cow’s risk for milk fever. More recently, research has focused on how reducing dietary phosphorus concentrations could help improve blood calcium and reduce the risk of hypocalcemia.
At the 2023 Tri-State Conference, Walter Grünberg, a German researcher, discussed his recent work on restricting prepartum dietary phosphorus content. One of the main highlights was a study that restricted dietary phosphorus (0.16% DM) in close-up dry cows for the four weeks prior to calving. Cows that were fed the restricted phosphorus diet prepartum had decreased blood phosphorus concentrations, while also having significantly greater blood calcium concentrations relative to their counterparts fed a diet adequate in dietary phosphorus (0.30% DM).
Cows fed the restricted phosphorus diet prepartum also had increased markers of bone mobilization. Mobilizing bone is a crucial part of a cow’s physiology to maintain blood calcium as she starts to synthesize colostrum and milk. Bone is a major supplier of calcium during times of extreme demand, such as lactation, due to the large stores of calcium (and phosphorus) found within bone. These signals to mobilize bone in the current study appear to be induced through the presence of low blood phosphorus concentrations, a result of the restricted dietary phosphorus intake. Grünberg’s results indicate that restricting dietary phosphorus content in the close-up dry cow can improve blood calcium status primarily by driving bone resorption.
Grünberg’s research is not the first to show the relationship between dietary phosphorus and blood calcium in the dairy cow. Historically, research has demonstrated that increasing levels of dietary phosphorus results in lower blood calcium concentrations and increased risk of milk fever. This same concept holds true in other species, with work demonstrating that high blood phosphorus concentrations can inhibit vitamin D synthesis. However, a dietary phosphorus restriction large enough to robustly decrease blood phosphorus concentrations and induce bone mobilization to support calcium demand and improve blood calcium at calving had not been studied in the dairy cow until now.
Stay tuned for more on phosphorus restriction pre-fresh and implications on blood calcium —don’t hit the snooze button!
References
Goff, J. P. 2006. Macromineral physiology and application to the feeding of the dairy cow for prevention of milk fever and other periparturient mineral disorders. Animal Feed Science and Technology. 126:237-257.
Lean, I.J., P.J. DeGaris, D.M. McNeil, and E. Block. 2006. Hypocalcemia in Dairy Cows: Meta-analysis and Dietary Cation Anion Difference Theory Revisited. Journal of Dairy Science 89:669–684.
Rader, J. I., Baylink, D. J., Hughes, M. R., Safilian, E. F., and M. R. Haussler. 1979. American Journal of Physiology. Calcium and Phosphorus Deficiency in Rats: Effects on PTH and 1,25-dihydroxyvitamin D3. 236:118-122.
Wächter, S., I. Cohrs, L. Golbeck, M.R. Wilkens, and W. Grünberg. 2022. Effects of restricted dietary phosphorus supply to dry cows on periparturient calcium status. Journal of Dairy Science 105:748–760.
Is your Biosecurity ready for Avian Influenza?
Biosecurity plays a vital role in protecting farms against disease outbreaks. With the recent surge of Avian Influenza (AI) cases across flocks in North America, the need for effective biosecurity measures has never been more evident.
Components of Effective Biosecurity
In a recent article composed by the Poultry Industry Council, three key components of biosecurity were highlighted. Isolation, Traffic Control, and Sanitation. In addition to these three components, a biosecurity program must be practical and scientifically sound.
Isolation. The containment of your flock within a controlled environment. A controlled environment is important as the AI virus is easily spread through mechanical transmission.
Traffic Control. Knowing who and what is entering and leaving your environment. Controlled access points. Visitor logs.
Sanitation. The implementation of products is effective in mitigating the risk of contagious diseases.
Modern biosecurity in the swine industry
The health status of swineherds has significant implications on animal welfare and production efficiency, including growth rate, feed conversion, and profitability. Therefore, swine producers and veterinarians work daily to improve and maintain the health of their herd through critical biosecurity practices. There are many definitions of biosecurity. Simply put, biosecurity is practices implemented to prevent the introduction or prevent the further spread of pathogens capable of causing disease.