A vaccination strategy for the prevention and reduction of clinical disease is of paramount importance on every dairy farm and young stock operation in the world. Along with excellent husbandry, great nutrition, and diligent biosecurity, vaccination provides the “hedge of protection” we need to effectively manage infectious (viral and bacterial) disease.
Last week, our group spent an evening with Vic Cortese, chief bovine immunologist for Zoetis, discussing recent advancements and current thoughts on dairy immunology. I will share several take home messages I found very helpful.
It starts with calves
The U.S. dairy industry has done awesome with the neonatal calf. Great job, team!
Many of you have designed and built new calving facilities, which allow for improved cleanliness and the rapid harvest of colostrum from well-immunized dams. We are routinely screening 2- to 7-day-old baby calves, finding serum total protein levels 6 mg/dL and above. This practice of rapid collection and feeding high-quality, clean colostrum is making a real difference in these calves.
New research continues to shed light on the beneficial effects of colostrum fed beyond the traditional first feeding. It appears that colostrum, the rocket fuel for immunity, provides cellular and noncellular nutrients that jump start health benefits to be realized months, and even years, down the road!
Because of this improvement in passive transfer of immunity, many of our previously used injectable viral vaccination schedules may need to be delayed several weeks to several months, due to interference from maternal antibodies. Herd level screening (around 20 calves) of serum antibody “cut point” titers will help establish the best time to immunize for optimal viral (especially bovine viral diarrhea or BVD) response.
This prolonged maternal antibody is a positive result with tangible benefits. Our industry has seen good efficacy with intranasal vaccination in newborns, boostered at preweaning, then followed with an injectable vaccination. The intranasal vaccines are not affected by high circulating levels of maternal antibody.
The bottom line is that young calves rely heavily on the dam to provide the best protection early in life. Avoid hyper-vaccinating with a large number of antigens, which can be rough on the neonate during the early milk-fed period.
Providing nutrition to enhance growth (doubling birth weight at weaning) allows the immune system to properly develop and gain momentum. Remember, the immune response, either due to natural exposure or vaccination, requires plenty of energy and essential nutrients for protection from disease.
Additionally, always invest wisely in prevention. It provides great dividends in return! Excessive exposure to pathogens, especially gram-negative bacteria that typically come from the environment or sanitation issues, is a critical risk area for young calves. Provide lots of clean, dry straw in your hutches or pens. Straw is cheap prevention! Also, utilize sanitation audits to bring attention to risk areas or items.
It is super rewarding to walk calf facilities today. Your hard work is evident! It’s much more difficult for me to catch healthy critters to check on them . . . and that’s a good thing!
Minimize the risks
Cortese brought to our attention that as he visits and consults on farms coast to coast, BVD is alive and well. Our vet team echoes his sentiments, as we continue to identify persistently infected (P.I.) BVD calves routinely in practice. The changing demographics of our industry and movement of large numbers of replacement animals long distances require steadfast diligence with this viral disease.
Most P.I. calves originate from heifers being infected during their first pregnancy. We must rely on timely initial immunization and pre-breeding boosters to keep our risks at a minimum. Remember, no vaccine is 100 percent effective, but we should “stack the deck” in our favor with respect to BVD.
This viral disease is the real deal on farms. It seems to partner with other nasty bugs such as salmonella, several bacterial pneumonia agents, and so forth, providing the “perfect storm” in germ warfare!
Many dairies also include a vaccination strategy for reduction of disease caused by Salmonella spp. As we are well aware, salmonellosis is a zoonotic disease (transferable from animals to humans) and is reported weekly in human disease outbreaks.
I remember my first salmonella outbreak on Steve’s small registered Holstein herd 35 years ago. I recall four or five lactating cows being infected. They all recovered, and the outbreak was over. How things have changed.
Today, cases are often more challenging to diagnose and successfully treat. Some salmonella strains are “host adapted,” allowing the bacteria to be “off the grid” for periods of time. As for now, we must rely on biosecurity, management, early detection, and immunization to provide protection from outbreaks.
Many herds, especially large ones, are also routinely vaccinating for adult bovine bacterial pneumonia (Mannheimia, Pasteurella, and Biberstinia). Years back, a mention of a herd (or adult cow) suffering from pneumonia would provoke a discussion of the “whys” back at the office, as it was that uncommon. Today if the acute disease is severe, animal loss is tragic. Vaccination has been quite rewarding if combined with attention to contributing environmental factors (ventilation, stocking density, and such).
Vaccinations have evolved
Advancements in the understanding of bovine immunology over the last several years has been nothing short of amazing. Collaborative research with human and veterinary immunologists worldwide continues to shed light on our (and our herd’s) ability to resist infectious disease.
Utilizing modern novel vaccination strategies, along with responsible biosecurity and great husbandry, provide a key element for dairy success. No one “perfect” vaccination schedule exists. We must remain diligent in diagnosis on an individual animal and herd basis and tailor schedules to provide maximum protection from disease. Always invest in prevention.
Cheers for 2020 to your family and the animals you provide so much for. God created the farmer to be special . . . this I know.