Calfhood vaccination to prevent post-weaning BRD

By John Maday, Editor, Bovine VeterinarianApril 14, 2015 | 6:15 pm EDT
Drover's Cattle Network

During last week’s Academy of Veterinary Consultants conference, Phil Griebel, DVM, PhD, presented research results suggesting vaccinating newborn calves, using a modified live, intranasal vaccine, can provide protection against pathogens causing bovine respiratory disease later in life.
Griebel is a research fellow at the Vaccine and Infectious Disease Organization and professor in the School of Public Health at the University of Saskatchewan. In his research, he studies the mucosal immune system in newborn calves. Over 70 percent of the cattle immune system, he says, is associated with epithelial cells on the surfaces of the respiratory, gastro-intestinal and reproductive system. And over 90 percent of pathogens, both respiratory and enteric, enter the animal’s system through mucosal surfaces.
Shortly after birth, the mucosal surfaces of newborn calves are rapidly colonized by a wide variety of commensal microbes, which affect the development of the mucosal immune system, Griebel says. This is especially true in the upper respiratory system, which is the first point of infection for pathogens entering through the nostrils.
Using an intranasal vaccine within the first four weeks of a calf’s life potentially can provide several benefits, Griebel says.

· Protection when cows were not properly vaccinated pre-calving.

· Protection in cases of sub-optimal transfer of maternal antibodies.

· Protection when immune status of the cow and calf are unknown.

· Protection in the face of an outbreak of respiratory or enteric disease among newborn calves.

· Enhanced immune protection while maternal antibodies wane as the calf ages. Griebel says the early vaccination can establish an immune memory that provides protection during the early post-weaning period, particularly when compared with vaccinating weaned calves upon arrival at backgrounding or feeding operations, when it takes the vaccine three to four weeks to provide protection.

Griebel also notes that immunoglobulin A (IgA) is the primary antibody secreted at the mucosal surface, and within a few days after a calf’s birth, most of the maternal IgA has been cleared from the respiratory mucosal surface, leaving little to interfere with activity of the vaccine.
Griebel outlined a pair of trials he conducted, one to compare immunity between calves receiving a modified-live, intra-nasal vaccine at branding time (three to six weeks of age) and non-vaccinated control calves, and another study to compare the effects of calfhood intranasal versus intra-muscular modified-live vaccines on immune memory.
In the first trial, researchers vaccinated one group of calves using the modified-live, intranasal vaccine and used a diluent (non-active fluid) intranasally on the control calves. Prior to weaning, they collected serum and selected 20 health calves from each group, which were shipped to the feedlot a week later. After a short receiving period, all the calves were challenged with aerosol containing bovine herpesvirus 1 (BHV-1), the virus associated with Infectious Bovine Rhinotracheitis (IBR), one of the common causes of BRD. At the same time, they segmented the two groups and vaccinated again with the intra-nasal vaccine. This created four groups: One group with no vaccination, one with two vaccinations, one with an early vaccination but no late vaccination and one with late but not early vaccination.
Results included:

· Control cattle lost 20 kg of body weight over the first seven days post-challenge, while the calves vaccinated twice maintained weight.

· The twice-vaccinated calves had significantly lower body temperatures than controls during the first seven days post-challenge.

· All calves were shedding virus by day three, but control calves continued to shed large volumes while the twice-vaccinated calves stopped shedding by day 12. Calves that received the neonatal vaccine but not the weaning vaccine were intermediate in shedding.

· Secondary bacterial infections caused some death loss in control calves but not in either of the vaccinated groups.

· A single intranasal vaccine at three to six weeks of age reduced BRD mortality but not clinical disease.

· Vaccinating early and again at weaning reduced clinical BRD incidence.

In the second trial, the researchers used a similar process except that at branding, they divided calves into six groups. Two received an intramuscular modified-live vaccine, two received an intramuscular killed vaccine, one received the intranasal modified-live vaccine and one group received a diluents.
In this trial, both of the modified-live vaccines helped reduce fever and reductions in gain during the post-challenge period, but the intranasal vaccine was the only one shown to induce sufficient immune memory to reduce the incidence of clinical disease.

Scientists dispute study on antibiotic residues in feedyard dust

By John Maday, Editor, Bovine VeterinarianApril 03, 2015 | 5:58 pm EDT
Drovers Cattlenework

In January, we covered a report from Texas Tech University’s Institute of Environmental and Human Health, outlining a study in which researchers detected antibiotic residues, bacteria and genetic material related to antibiotic resistance in particulate matter downwind of Texas feedyards.
The research paper, titled “Antibiotics, Bacteria, and Antibiotic Resistance Genes: Aerial Transport from Cattle Feed Yards via Particulate Matter,” was published in the Journal of Environmental Health Perspectives.
This week, Michael D. Apley, DVM, PhD at Kansas State University, Samuel E. Ives, DVM, PhD at West Texas A&M University and H. Morgan Scott, DVM, PhD at Texas A&M University released a white paper citing concerns over the conclusions listed in the Texas Tech report.
The three research veterinarians focused on issues of bacterial viability, likelihood of bacterial repopulation and the concentration of antimicrobials found in the feedyard particulates.
“In this paper, many inferences are presented as conclusions when in reality they are actually untested hypotheses,” they wrote. Contrary to much of the media representation of this research, the data do not indicate that there are any viable bacteria present in their samples. The likelihood of non-viable bacterial genes transforming into other living bacteria is of very low probability. The antimicrobial concentrations used in this study are not grounded in appropriate air and soil volume concentrations and do not accurately represent the dispersion and dilution of these agents in the environment.” In an interview published this week in the Journal of Environmental Health Perspectives, Dr. Ives says “qPCR techniques only reveal the presence of bacteria, not their viability. That doesn’t translate to transference to the environment and beyond.”
Read the full white paper from Drs. Apley, Ives and Scott.

Progress or Change

By Burke Teichert || Originally published in BEEF Magazine and at www.beefmagazine.com

In my lifelong learning, I’ve relied on many sources but the most meaningful help has come from two of them:

• Experts from the academic world who have the confidence of their peers and their students, have learned to work and communicate effectively with farmers and ranchers, and whose work addresses economically important questions.
• Farmers and ranchers who are possibility thinkers, pay attention to the science, learn from each other, want to know the truth and adopt practices and careful decisions that make them more profitable.

It is from this perspective (paying attention to the science and observing the practices of profitable commercial ranchers) that I make the following observations on cattle breeding and the way we select and cull.

• Years of observation suggest that the most profitable ranches have cow herds that are at, or just slightly above, average for most economically important traits. The most profitable herds also have lower-than-average milk production. Trying to push a herd beyond average for an environment usually comes with a cost in feed or stocking rate.
• There are many genetic antagonisms (unintended consequences) which can vary from almost imperceptible at first to fairly significant.
• We can make rapid genetic change, but it doesn’t always yield economic progress. Looking at the dairy industry as an example, we see that, if you select primarily for milk, you will get lots of milk. You will also get significant inbreeding as a result of extensive use of artificial insemination (AI) to closely related sires, poor fertility, poor survivability, many health issues and lots of cost. To a lesser extent, I think that focused selection in beef cattle for high growth and carcass grade has yielded some of the same effects.
• Please understand that EPDs and genomically enhanced EPDs work, but too many people have used EPDs as a tool to strive for “maximums.” Maximum is seldom, if ever, the most profitable course.

Improvement Carries a Cost

Most improvement in performance comes with a cost. Often, that cost is in the reduction of performance in another trait, a reduction in stocking rate, or higher feed costs, each of which can take several years to become obvious. We need to be sure the added revenue is greater than the added cost.

• The use of AI, embryo transfer and today’s genomically enhanced EPDs, without great care, can lead to a significant increase in inbreeding for the most popular breeds.
• If cell division to form egg and sperm happened for each gene pair individually, I would not have so much concern. But cells divide a chromosome at a time, which means that to get the good stuff on a particular chromosome, you will also have to take whatever else happens to be on that chromosome – the possible antagonisms.
• The relatively new study of “epigenetics” suggests that environmental factors may turn genes on or off. I think one might further suppose that environmental factors can reduce, enhance or even modify the effect of genes. Genes also have effects on each other – most of which are unknown and unmeasured. That’s just the way complex systems work.
• Many geneticists and a number of seedstock breeders are promoting the use of selection indices. The index becomes a composite of the “economically relevant traits.”

In putting the index together, each trait receives a weighting based on heritability and economic importance. From environment to environment, the relationship of heritability from trait to trait is seldom the same (though it may be close). The relative economic importance of each trait can also vary from place to place and from time to time. There is just enough skeptic in me (I call it being careful) to wonder if the economic weighting for each trait in the index was done correctly for my objectives.
Being a “systems thinker,” considering the forgoing observations and recognizing that the use of EPDs can move us toward or away from our profit objectives, I want to suggest the following combination of management and genetics as a method of herd improvement:

• Cull cows that aren’t doing what you want them to do. Don’t expect careful culling to be a big genetic trend changer. It won’t be. But, it will keep your herd cleaned up, functional and easy to manage. It will help you avoid keeping offspring from the poorest few. I have noticed that, when culling for unacceptable disposition or performance, you only have to remove a few each year to keep problems at a low level and to make life easier and much more enjoyable.
• Use low-cost development and a very short breeding season for yearling heifers, exposing significantly more than will be needed. If you start with heifers that can be developed at a low cost and get pregnant in less than 30 days, you will have better cows raising better calves and with better rebreeding rates. Naturally you will sort off the real misfits before breeding.

This is more management than genetics, but it will give much quicker bottom-line results. This is written from the perspective of one who produces his own replacement heifers. However, if your better alternative is to buy bred cows, you should try to find a producer who comes close to following these recommendations for your source of bred cows.
You must depend on your seedstock provider(s) to make most of the genetic changes you desire in your herd. I want my bull provider to:

• Judiciously use the genetic tools at his disposal.
• Produce and help me select bulls that will produce good mother cows – moderate in size and milk production, and that will work in my environment and with my management. He needs to be a low-cost, low input operator with his cowherd. Since I don’t pamper my cows, I don’t want him to pamper his. Sure, I want good steer calves, but I want mother cows first. A good mother will usually produce an acceptable steer and do it with low cost.
• Keep accurate individual records and report 100% of the records to his breed association. I don’t like the problems or inferior performance to be excluded from the records.
• Help me maintain a reasonable level of heterosis in my herd (somewhere between 65 and 80% of maximum or F1 heterosis). This means I will either need more than one seedstock supplier or the chosen supplier will be able to provide genetics from at least three breeds.
• Not follow popular fads without good justification.
• Be satisfied with slow, sustained, balanced progress. Many years of watching has shown that, when you try to move one trait too far or too fast, you usually give up something else that is good. Balance is very important.
• Beware of, and be honest about, genetic antagonisms as they manifest themselves. While I’m sure I’ve observed many cases of bigger mature size and higher milk being negatively correlated with reproduction, I also see a negative correlation with stocking rate, which is not a genetic correlation. This kind of relationship between a genetic trait and a non-genetic effect needs to be considered.

We have great tools; but, because of genetic and environmental antagonisms, I think we need to be satisfied with slow change in a balanced approach – maintaining or slowly improving genetics for cowherd productivity. Any genetic change that results in more feed cost, a reduction in stocking rate, or a reduction in reproduction should be questioned.

Private Applicator

Note:
I posted yesterday that I would host a Private Applicator Training on April 23rd.  That has been changed to April 21st.  Again if you or someone you know needs to get their PA License. Please call in to reserve your spot.  356-4417.

News updates

Sorry all I haven't updated much lately on the blog.

For all producers:

USDA will be conducting a grasshopper survey in late April.  If you are having problems or see an unusual amount of grasshopper activity, please give me a call here at 356-4417 and I will update the technicians about the problem location.

NOTE:CHANGE!!!

I will be hosting a Private Applicator Training course on April 21st from 1:30 pm to 3:30 pm in the McAlister Room.  This is for individuals that need to get a license.   If you are interested in taking the course or know someone that needs the course please call 356-4417.