by Kelly Driver
It is widely recognized that colostrum is the single most important meal for newborn dairy calves, delivering essential nutrition, immunoglobulins (Ig) and other important factors vital to setting up a newborn for lifetime success. Highly anticipated new recommendations about passive immunity standards for newborn calves have been published in the August 2020 issue of the Journal of Dairy Science. So, letâs take a look at what research has shown over the years and what the most recent recommendations offer for both individual calves and herd-level goals, as the industry moves again to further improve calf health and reduce morbidity and mortality in young calves.
The back story.
Passive immunity in dairy calves is evaluated by measuring the serum total protein (STP) or plasma IgG within the first seven days of age. The standard for individual calves to be categorized with successful passive transfer for the past 30 years has been >10 g/L serum IgG, while failure of passive transfer of immunity (FPT) was a serum IgG concentration <10 g/L. These levels correlate directly to STP levels of >5.2 g/dL (pass) and <5.2 g/dL (fail).These cutoffs were established based on higher mortality rates in calves with serum IgG <10 g/L.
Studies have shown.
Research conducted by USDA National Animal Health Monitoring System (NAHMS) in 1991 showed that 41 percent of U.S. dairy calves had failure of passive immunity. With education and outreach, NAHMS reported an improvement to 19.2 percent of calves in 2007 and 13.7% in 2014 studies. Over this same time period, preweaned death rates decreased from 10.8% in 1996 to 6.4% in 2014, but the number of sick calves remained at nearly 30 percent.
Jason Lombard, DVM, MS at USDA/NAHMS reported at the 2020 Dairy Calf and Heifer Conference that in the spring of 2018, a group of eighteen U.S. and Canadian calf experts first gathered to scrutinize the 2014 NAHMS calf data, and discuss other published literature to propose new passive immunity standards. The group emphasized that new standards âneeded to be realistic and achievable,â related Lombard to the virtual attendee audience.
Time for an upgrade.
Research has repeatedly shown that healthier calves have improved rates of gain and feed efficiency, resulting in earlier breeding and calving, along with better first and second lactation milk yields. Studies in both dairy and beef calves have also shown reduced morbidity in calves with higher serum IgG levels. Lombard reported the industry group consensus includes four categories, each with corresponding serum IgG concentrations, serum total protein, and Brix percentages. Additionally, the group recommended the percentage of calves that should fall into each category, based on the 2014 NAHMS calf study.
New transfer of passive immunity goals for U.S. dairy calves
|Category||Serum IgG categories (g/L)||Serum total protein level (g/dL)||Brix level (%)||Farm Level % calves|
|Excellent||> 25.0||> 6.2||> 9.4||> 40%|
|Good||18.0 – 24.9||5.8 – 6.1||8.9 – 9.3||– 30%|
|Fair||10.0 – 17.9||5.1 – 5.7||8.1 – 8.8||– 20%|
|Poor||< 10.0||< 5.1||< 8.1||< 10%|
Lombardâs group went on to provide two colostrum feeding recommendations, based on the results of the NAHMS Calf Component survey, to help dairy producers achieve the new passive immunity recommendations:
- A single feeding of colostrum, delivering approximately 300g of IgG, fed at approximately 2 hours after birth, or
- Feeding multiple colostrum feedings and delivering approximately 400g of total IgG in the first 24 hours. (Lombard, 2021)
With nearly 90 percent of calves now meeting the previous pass/fail standard of 10 g/L for serum IgG concentration, that standard was successful in challenging dairy producers to improve their newborn calf protocols and colostrum management. Are you ready for the new challenge to further improve calf health and dairy farm success?
Kelly Driver, MBA has been involved in the New York dairy industry all her life. In addition to raising dairy calves and replacement heifers, she is the Eastern US & Canada Territory Manager for Calf-Tel. Feel free to contact her at firstname.lastname@example.org with your calf questions or suggest a topic you would like addressed in a future blog.
- Godden, S.M., J.E. Lombard, and A.R. Woolums. 2019. Colostrum management for dairy calves. Vet. Clin. North Am. Food Anim. Pract., 35:535-556.
- Lombard, J. (2020, April 8). New passive transfer standards for dairy calves and how to achieve them. Presented at Dairy Calf and Heifer Association Conference.
- Lombard, J.E., N. Urie, F. Garry, S. Godden, et al. 2020 Consensus recommendations on calf- and herd- level passive immunity in dairy calves in the United States. J. of Dairy Science, 103:7611-7624.
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