Are you only treating cows with visible milk fever symptoms?
For every cow that shows signs of milk fever (stumbling, off-feed, or simply looks “off”), there are many others silently dealing with subclinical hypocalcemia (SCH). Unlike clinical hypocalcemia (milk fever), cows with SCH don’t present obvious symptoms, making detection a management challenge. Cows with SCH have low calcium levels (ionized calcium (iCa) <1.0 mmol/L) and are at risk for decreased milk production, reduced reproductive performance, increased inflammation and health issues, and have a higher risk of being culled.
Even with a well-managed negative dietary cation-anion differential (DCAD) close-up diet, 25-50% of your second-lactation and older cows may still experience SCH after calving. That means some of your cows might be struggling with SCH before you even notice.
While calcium boluses are often used to treat clinical milk fever, they can also be a preventive measure for SCH. Research conducted by an independent veterinary research company at a 6,000-cow dairy showed that incorporating Ca3 BioFresh® Boluses into a fresh cow program improved calcium levels and mitigated the effects of SCH. Cows given one bolus within three hours of calving had improved calcium levels within 12 hours; and adding a second bolus 12 hours after calving boosted calcium levels higher for longer. This proactive approach didn’t just enhance calcium levels; it helped cows transition more smoothly leading to better health post-calving.
Study details
The 6,000-cow dairy used a close-up diet designed to maintain urine pH at 6.0–6.5. Researchers tested three groups of second-lactation and older cows:
- No Bolus: Cows received no supplemental calcium.
- One Bolus: Cows received one bolus within three hours of calving.
- Two Boluses: Cows received one bolus within three hours of calving and another 12 hours later.
Researchers measured blood calcium levels at calving and at 12, 24, and 48 hours post-calving to determine how the treatments impacted iCa levels. Only cows with four sampling times were included in the statistical analysis.
- At 12 hours post-calving: Cows receiving one bolus (Trt 1) showed improved calcium levels (1.06 mmol/L), and cows receiving two boluses (Trt 2) had even higher levels (1.08 mmol/L), compared to the control group.
- At 24 hours post-calving: Cows given two boluses maintained significantly higher calcium levels (1.00 mmol/L) than the control and single-bolus groups.
- At 48 hours post-calving: All groups had similar calcium levels, but the early intervention from boluses helped the treated groups avoid dips during the critical early hours.
If you’re already using calcium boluses to treat clinical milk fever, consider proactively treating SCH. You know fresh cows are key to your herd’s success and supporting them with calcium during this critical time can make all the difference. By addressing SCH early, you’re ensuring the long-term health and productivity of your herd.
Author: Larry Roth, Ph.D., PAS, Agrarian Solutions Vice President of Nutrition