All throughout my life I have heard people say “You can’t teach an old dog new tricks”. This means that once you learn something and do it this one way over time you will do it that one way forever. If you are a cattle farmer this is impossible. Learning, listening and adapting are some of the greatest tools that a cattle farmer can have. The cattle industry is constantly changing as a result of consumer preferences, new innovations being created, and methods being improved. Learning and improving is something that all farmers must do. That has been kept at the heart of the mission of Eden Shale Farm. When the Kentucky Beef Network took over the management of Eden Shale Farm in 2012 the goal was to educate cattlemen using a hands-on approach. On the farm, they use many Beef Quality and Care Assurance (BQCA) practices to help guide how the farm is operated and improved. When you are creating your facilities, choosing what is the easiest is not always the best option. The care aspect of BQCA involves keeping the health, safety and wellbeing of your animals at the fore front of your mind. This involves not only how you handle your animals but also their surroundings and resources such as the waterers they drink from, where they eat hay, or where they go for shade.
Additionally, Eden Shale Farm is known for its many features that have been improved upon or built to help educate cattlemen that visit the farm. One of features is the calving barn. One of the biggest things done to help improve this barn was that the floor was dug down to solid soil and then a layer of geotextile filter fabric was added, then 6 inches of dense grade aggregate. Then Geo-Grid interlocking pieces. This created an interconnected floor. The benefits of these changes is that this floor is very easy for the cattle to walk on, moisture is easily drained out so that mud does not develop and even if there is an abundance of moisture for some reason there is still a solid layer that the cattle walk on. Furthermore, since the moisture drains easily, bedding that is put down in here lasts much longer. Giving cattle a dry shaded space can help greatly improve productivity and reduce sickness.
Tire waterers are one of the most widely used features of Eden Shale Farm. All throughout the farm there are various versions of the beloved waterers. A tire-tank waterer can typically hold 500-800 gallons, depending on the size of the tire. A larger diameter means more livestock can drink at one time (e.g., 10-16 head versus one to two for automatic water fountains). When the entirety of the herd goes to get a drink and only 1 can drink at a time, this creates a pile up of cattle waiting to get a drink. It increases the heat since they are standing on top of each other waiting, the cattle also usually do not get the opportunity to drink as much as they want and since it takes so long the herd is usually already leaving before some cattle get the chance to get a drink. With a tire waterer this helps to fix all these problems. Additionally, cattle like to drink together in groups and this gives them the ability to do so. Adding a tire waterer can help keep cattle in better condition, keep them more content and keep them satisfied.
Adding the simple step of making sure to incorporate care into your operation is one of the best steps you can do to improve the productivity and wellbeing of your animals. It can be added to every facet of your farm. From the waterers they drink from, where they go to get shade or the facilities where you work them. And if you need a couple ideas to get started, the Eden Shale Farm open house will be on October 19th or you can check out the resources page on the Eden Shale Farm website https://www.edenshalefarm.com/.

​As I am writing this, we just finished the last of the Spring value-added sales that we at the Kentucky Beef Network help support. These sales include the Kentucky Certified Hereford Influence Sale, the Charolais Influenced Feeder Calf Alliance Sale and the Profit Thru Performance Feeder Calf sale. To put your calves into a sale like this is a great opportunity to help add more value to your calf crop and increase your sale profits.
Reading this, you may wonder what “value-added” means. Value-added applies to ways a producer markets their cattle to make them stand out from other animals. There are numerous ways to go about adding more value to calves that you intend to sale. This can include incorporating basic management practices like weaning, castration and testing for BVD.  That is exactly what the sales mentioned above are doing. They have created an outline of basic management processes that consignors must follow to have their cattle qualify for these sales. These practices help cattle in these sales standout from others as it reduces the workload the buyer has to do to get these animals to the next step on their journey.  Thus, sellers are rewarded for their additional work. It also creates an opportunity for producers to combine their like cattle and sell them as load lots, which also increases your profits.
The sales mentioned above use a mix of practices that help increase the return on the investment on the animals sold. With some planning and effort, most producers can easily incorporate some of these things into their livestock development program and capture those additional returns. To start, these sales have a set vaccination and worming protocol in place. This protocol can include vaccinating for things such as IBR, BVD and blackleg. Some other great management practices include castrating your bull calves and weaning all calves before sale time. Castrating your bull calves can instantly add more value to the calf in question. It can be incorporated into to the management protocols you are already doing on your operation. However, it may mean adjusting your cattle working schedule to catch the calf when it is still young or you may choose to castrate when you get all of your animals up to work them. Weaning your calves before the sale helps them have time to adjust to being away from their mother, which keeps them calmer at the sale barn. It also keeps them in better health with less chances of getting sick when they are sold. Another value-added practice is to work with your local veterinarian to pregnancy check the heifer calves you intend to sale.  You can gain additional value by guaranteeing that those heifers are open.
Overall, using these “value-added” practices can help to create more profitable marketing opportunities. When you do any of these practices, be sure that potential buyers know about them prior to the sale by including it in any description of the animals, making a note of it when you arrive at the stockyards or by placing your calves in a value-added sale with other producers. Remember you cannot be rewarded for extra work if the buyers don’t know about it.

​To raise an animal with respect means to care for an animal’s safety, care, and health. The Raised with Respect BQCA training put all of this together and gave attendees the opportunity to put what they learned into practice plus a bit more. The purpose of the day was to give a well-rounded experience that helped to show that how a farmer treats their animal matters and can have a lasting affect all the way to the plate that someone eats off of.
The day began with some opening comments and then we hopped right into a panel focused on the importance of beef quality. Attendees were able to ask the panel members any questions pertaining to why cattle handling and care mattered all the way from the pasture to the plate. The panel was made up of Chef Josh Moore from Volare Italian Ristorante, Chef Zach Wolf from Steak and Bourbon, Carey Brown of the Kentucky Beef Council and moderated by Kirsten Nickles from Certified Angus Beef. Beef quality matters for a lot of reasons; everybody wants a higher quality beef that also has a great look. The Chefs talked about why beef quality matters to them and how they themselves take pride in serving higher quality meats and how they appreciate the work that a farmer does to produce the meats we eat.
Next, attendees went through rotations that covered a wide variety of topics. Outside in the cattle handling facility Kevin Laurent from the University of Kentucky and Ben Lloyd of the Kentucky Beef Network guided attendees through a BQCA chute side training and cattle handling demonstration. This included how to safely and carefully move cattle and work them into a chute, where and how to safely give vaccinations, and all of the biosecurity that goes into working cattle. The next rotation was with Dr. Darrh Bullock and Dr. Katie VanValin from the University of Kentucky going over management practices for cattle care. Some of these practices included managing your cattle’s body condition scores so that they do not become too thin or too overweight, and using EPDs (Expected Progeny Differences) to guide your cattle herd towards a direction that is best for the animal’s care and for the producer as well. The last of the rotations was with Dr. Michelle Arnold with the University of Kentucky where she led a group about Spring vaccination protocols. This presentation gave attendees the opportunity to see the many options there are when it comes vaccinating their cow herd.
To begin the end of the day everyone headed back to the main room where they did their BQCA exams to receive their certifications while also enjoying some great appetizers from chef Josh Moore and Zach Wolf. After everyone had finished their exams, we then were given the amazing opportunity to eat a delicious meal that chef Josh and Chef Zach had made. To round out the night Paul Dykstra from Certified Angus Beef brought a market update that compared past to current prices and where the market was headed.
Overall, this was a great opportunity to get your BQCA Certification, hear some great talks from professionals, and enjoy a wonderful meal. A big thanks goes out to all the attendees, the speakers, Chefs Josh and Zach, and especially to Certified Angus Beef and Sysco. 

Hoof damage from livestock during the winter months can result in almost complete disturbance of desired vegetation and soil structure in and around heavy use areas. Even well-designed hay feeding pads will have significant damage at the edges where animals enter and leave. Highly disturbed areas create perfect growing conditions for summer annual weeds like spiny pigweed and cocklebur. Weed growth is stimulated by lack of competition from a healthy and vigorous sod and the high fertility from the concentrated area of dung, urine, and rotting hay. The objective of this article is to describe two approaches to revegetating these areas.
Regardless of the reclamation strategy that is employed, it is important to create an environment that will allow seeds to germinate quickly and uniformly, resulting in rapid canopy closure. This will help to inhibit weed seeds from germinating. Creating this environment starts with making sure that soil fertility is in the medium to high range, soil pH is 6.0 to 6.4, and preparing a fine, but firm, seedbed.
Plant cool-season grasses and legumes.
The first strategy is to seed cool-season grasses or a mixture of grasses and legumes in the spring. While this is commonly done, results are usually less than spectacular in most years. Seedings are normally delayed until late spring or early summer. Consequently, seedlings do not have time before the hot summer months set in. The second reason is that summer annual weed pressure is usually very high. Figure 1. Excessive rainfall and high livestock concentration in and around hay feeding areas can result in almost complete disturbance. Summer annuals weeds like foxtail, goosegrass, spiny pigweed, cocklebur, and others actively compete with cool-season seedlings for light and water, often causing stand failures.
If a spring planting of cool-season grasses and legumes is attempted, there are several things that can be done to enhance, but by no means guarantee, success. These are listed below. • Plant adapted forage species.

• Plant forages that are well adapted to Kentucky and the soils and drainage found on your farm. Tall fescue, red clover, and ladino clover are, by far, the best adapted and most versatile forage species for pastures in the Commonwealth. If this area is disturbed again, then investment in novel endophyte tall fescue varieties is not recommended. Information on the best adapted varieties for Kentucky can be found on the University of Kentucky Forages webpage.
• Consider leaving legumes out of the mix. While legumes are an important part of grassland ecosystems, herbicide options for controlling weeds in grass-legume mixtures are limited. Leaving legumes out will allow you to apply selective herbicides to control broadleaf summer annual weeds. For specific herbicide recommendation, you can visit with your local Extension Agent.
• Use the high end of the recommended seeding rate. Seeding rates are normally given as a range (Table 1). For spring seedings, make sure and use the high end of this range. Rapid canopy closure is critical to suppressing summer annual weeds.
• Plant as early as possible. Spring seeded cool-season forages should be planted starting in early to mid-March. Early plantings will have more time to emerge and form a canopy that can shade summer annuals weeds. Early planted grass seedlings will also have additional time to develop a root system that can sustain the new planting during the summer months.
• Plant in two directions. If drilling, cut seeding rates in half and plant in two directions. This will aid in obtaining quicker canopy closure, helping to reduce the germination of weed seeds.
• Use a shallow seeding depth. Small seeded cool-season forages should not be planted deeper than ½ inch. Make sure to check and recheck your seeding depth. Seeding deeper than ½ inch will delay emergence, result in uneven stands, and in many cases cause complete stand failure.
• Control broadleaf weeds in cool-season grasses. Once seedlings have four collared leaves, some herbicides can be applied. Always consult and follow label directions. For the most up to date information on using herbicides on new seedings, contact your local Extension Agent.
• Clip or flash graze new stands. Summer annual weeds compete very aggressively for light, water, and nutrients with cool-season grass seedlings. If not controlled, plantings will likely fail. The most effective control of competition is to flash graze paddocks before weeds get well established. Table 1. Seeding rates for perennial cool-season forage species planted ALONE or in a MIXTURE. Species Seeding Rate (lb/A) Alone In a Mixture Tall fescue 20-25 10-15 Orchard grass 15-20 6-8 Perennial Ryegrass 20-25 10 Kentucky Bluegrass NR† 4-6 Red clover†† NR 6-8 White clover†† NR 1-2 †NR, not recommended ††Do NOT include red and white clover if herbicides will be used to control broadleaf weeds. Flash grazing is accomplished by placing a large number of animals in small areas for a short period of time. This reduces selective grazing and increases grazing uniformity.

 

​Plant cool-season grasses and legumes.
The first strategy is to seed cool-season grasses or a mixture of grasses and legumes in the spring. While this is commonly done, results are usually less than spectacular in most years. Seedings are normally delayed until late spring or early summer. Consequently, seedlings do not have time before the hot summer months set in. The second reason is that summer annual weed pressure is usually very high. Figure 1. Excessive rainfall and high livestock concentration in and around hay feeding areas can result in almost complete disturbance. Summer annuals weeds like foxtail, goosegrass, spiny pigweed, cocklebur, and others actively compete with cool-season seedlings for light and water, often causing stand failures.
If a spring planting of cool-season grasses and legumes is attempted, there are several things that can be done to enhance, but by no means guarantee, success. These are listed below. • Plant adapted forage species.

• Plant forages that are well adapted to Kentucky and the soils and drainage found on your farm. Tall fescue, red clover, and ladino clover are, by far, the best adapted and most versatile forage species for pastures in the Commonwealth. If this area is disturbed again, then investment in novel endophyte tall fescue varieties is not recommended. Information on the best adapted varieties for Kentucky can be found on the University of Kentucky Forages webpage.
• Consider leaving legumes out of the mix. While legumes are an important part of grassland ecosystems, herbicide options for controlling weeds in grass-legume mixtures are limited. Leaving legumes out will allow you to apply selective herbicides to control broadleaf summer annual weeds. For specific herbicide recommendation, you can visit with your local Extension Agent.
• Use the high end of the recommended seeding rate. Seeding rates are normally given as a range (Table 1). For spring seedings, make sure and use the high end of this range. Rapid canopy closure is critical to suppressing summer annual weeds.
• Plant as early as possible. Spring seeded cool-season forages should be planted starting in early to mid-March. Early plantings will have more time to emerge and form a canopy that can shade summer annuals weeds. Early planted grass seedlings will also have additional time to develop a root system that can sustain the new planting during the summer months.
• Plant in two directions. If drilling, cut seeding rates in half and plant in two directions. This will aid in obtaining quicker canopy closure, helping to reduce the germination of weed seeds.
• Use a shallow seeding depth. Small seeded cool-season forages should not be planted deeper than ½ inch. Make sure to check and recheck your seeding depth. Seeding deeper than ½ inch will delay emergence, result in uneven stands, and in many cases cause complete stand failure.
• Control broadleaf weeds in cool-season grasses. Once seedlings have four collared leaves, some herbicides can be applied. Always consult and follow label directions. For the most up to date information on using herbicides on new seedings, contact your local Extension Agent.
• Clip or flash graze new stands. Summer annual weeds compete very aggressively for light, water, and nutrients with cool-season grass seedlings. If not controlled, plantings will likely fail. The most effective control of competition is to flash graze paddocks before weeds get well established. Table 1. Seeding rates for perennial cool-season forage species planted ALONE or in a MIXTURE. Species Seeding Rate (lb/A) Alone In a Mixture Tall fescue 20-25 10-15 Orchard grass 15-20 6-8 Perennial Ryegrass 20-25 10 Kentucky Bluegrass NR† 4-6 Red clover†† NR 6-8 White clover†† NR 1-2 †NR, not recommended ††Do NOT include red and white clover if herbicides will be used to control broadleaf weeds. Flash grazing is accomplished by placing a large number of animals in small areas for a short period of time. This reduces selective grazing and increases grazing uniformity. 

​Plant warm-season annual grasses
The second strategy involves planting a summer annual grass in late spring or early summer. This strategy has a much higher probability of success than planting cool season grasses in late spring. Summer annual grasses, especially sorghumsudangrass or sudangrass, have very rapid emergence and canopy closure. This will prevent summer annuals weeds from germinating and provide forage for grazing or harvesting during the summer months (Figure 2). Perennial coolseason grasses can then be reseeded under more ideal conditions in late summer or early fall.
The following tips will help to enhance your chances of success when using warm season annual grasses.

• Plant adapted summer annuals species. Always plant forages that are well adapted to Kentucky and the soils and conditions on your farm. Summer annuals that can be used to reclaim hay feeding areas include sudangrass, sorghum-sudangrass, pearl millet, and crabgrass. A description of these species can be found in AGR-229, Warm Season Annual Grasses in Kentucky.
• Use the high end of the seeding rate. Seeding rates are normally given as a range. (Table 2). Make sure and use the high end of this range. Even with summer annuals, rapid canopy closure is critical for reducing unwanted weed competition.
• Plant after soil warms. For summer annual grasses to germinate and rapidly emerge, soil temperatures at planting should be at least 60 degrees F. This should allow plenty of time to let hay feeding areas dry out and to get them smoothed up prior to planting. If there is a delay in planting the summer annuals after final tillage, it may be a good idea to do one more pass of light tillage to disturb any weed seedlings that may have germinated.
• Control broadleaf weeds. Once warm-season annual grasses are established, some herbicides can be applied to control summer annual broadleaf weeds. If cool-season perennials are to follow in the fall, make sure and check the label for reseeding restrictions prior to application. Always consult and follow label directions. For more information on using herbicides on summer annual grasses, contact your local extension agent. Figure 2. Sorghum-sudangrass (left) formed a quick canopy that was able to shade out summer annual weeds compared with forage (right). Table 2. Seeding rates for commonly planted summer annual grasses in Kentucky†. Species Seeding Rate (lb/A) Sorghum-sudangrass 30-40 Sudangrass 15-20 Pearl millet 15-20 Crabgrass 4-6 †A small amount of crabgrass, 2-3 lb/A, can be seeded with the taller growing summer annual species to fill in thin spots in the stand that may develop
• Grazing summer annual grasses. Allow taller growing summer annuals like sorghum-sudangrass and pearl millet to reach a height of 18-24 inches before grazing and stop grazing at 8-10 inches. Regrowth can be stimulated be applying 40-60 lb N/A after each grazing but the last. Crabgrass can be grazed once it reaches a height of 6 to 8 inches. Cattle should be pulled off once it has been grazed to a height of 3 to 4 inches. Detailed management recommendations on for individual summer annual species can be found in AGR-229, Warm Season Annual Grasses in Kentucky.
• Haying summer annual grasses. Allow taller growing summer annuals to reach a height of 30 to 40 inches before mowing. This will optimize yield and forage quality. If regrowth is desired, do not mow closer than 6 inches. Apply 40 to 60 lb N/A after each cutting, but the last. Crabgrass should be cut for hay at the late boot-stage. Care should be taken to not mow crabgrass closer than 3 to 4 inches. With the taller, thicker stemmed species, a crimping mower-conditioner will help the crop dry to safe baling moistures, although this may take some time. Ideally, summer annuals should be conserved as chopped silage or baleage.
• Reseeding cool-season grasses in the fall. Pastures with summer annuals should be sprayed with a non-selective herbicide in late summer to control any remaining summer annual grass and any weeds that have germinated. Use a no-till drill to plant cool-season grasses into the killed pasture area. More information on forage establishment can be found in AGR- 64: Establishing Forage Crops

Kansas State University veterinarian Gregg Hanzlicek said being prepared ahead of calving season is the best way for producers to assure they will bring home the newborn calves successfully.
“We're approaching the end of the second trimester and moving into the third trimester which means the metabolic demands of that cow or heifer are going to increase tremendously,” Hanzlicek said.

A key to having a successful calving and production season is for cows and heifers to be in the appropriate body condition, which according to Hanzlicek is a score of 5-7. He said he has seen many cattle in the 3-4 range in the past few months.
“We’re far enough away from calving that we can add condition to these cows and heifers without (creating) an economic burden,” he said. “It really comes down to having a formulated ration that is balanced for protein and energy.”

For those wanting to add scour vaccines to their prevention program, “it’s time to decide what vaccine they are going to use,” Hanzlicek said. “Look at the label and schedule on the calendar when they need to start vaccinating the cows and heifers.”

Hanzlicek said heifers will require two doses of the scours vaccine, while cows need one. The timing of those vaccines is “very, very important,” he said.

Also, Hanzlicek recommends establishing a clean calving area to help reduce the risk of scours. “There’s two major risk factors for scours,” he said. “One is the lack of colostrum consumption. The other is a contaminated environment that the babies are born into.”

Hanzlicek recommends having a location to move the pairs off the calving area to keep the calving facility less contaminated with the scour organisms.

Getting the calf here safely is another factor to consider, "Most operations are going to have to help at least one animal during the calving season,” Hanzlicek said. The last national survey indicated that 1 of every 100 heifers and 2 of every 100 adult cows will need assistance.

Being prepared to pull a calf is important. Hanzlicek said producers should have the following items on hand:

• Clean straps or chains.
• OB sleeves.
• Lube.
• Working calf pullers.
• Veterinarian's phone number.

​Intervening at an appropriate time is important. “If we intervene too early and the cow or heifer is not dilated, we can injure the tissues and hurt the calf,” Hanzlicek said. “If we intervene too late, a lot of times that’s when we end up with stillborn calves.”

According to Hanzlicek, once a cow has reached the second stage of labor, they should give birth within 30 minutes. A heifer should calve within an hour. Second stage labor is when the heifer or cow can be observed experiencing uterine contractions, or the water-bag or calf’s feet are visible.

If assistance from the producer is needed, and they are unable to extract the calf within 15 minutes, then help – either a veterinarian or someone with more experience -- should be called.

Following calving, the calf should be up and nursing within two hours, Hanzlicek said. If not, a colostrum replacer can be given to help get the calf started.
“Colostrum-based powders are the best way to go, and I would recommend that every producer have one or two bags of powder replacer on hand during the calving season,” Hanzlicek said.

“BVD” or “Bovine Viral Diarrhea” virus is one of the most common and costliest viruses affecting KY cow/calf herds and backgrounding operations. Control of the BVD virus is best accomplished through implementation of three equally important practices: 1) surveillance testing to detect and remove infected cattle, 2) vaccination to increase herd immunity and 3) implementation of biosecurity measures to reduce virus entry into the herd. But how would a producer know that BVD virus is circulating in his or her herd? This article, the first in a two-part series, is written to help understand how BVD virus enters a beef herd and how to recognize its effects, and targets for control. Part 2 will address diagnostic testing strategies, how to correctly interpret results, and how to implement BVD virus measures.
One of the initial problems with this virus is its name. Although BVD stands for “Bovine Viral Diarrhea”, rarely does an animal show any symptoms of diarrhea. Instead, cow-calf producers may observe one or more of the following disease manifestations in the herd:
1. Poor reproductive performance despite females in good body condition and fertile bulls.
a. More open cows-Producers may find a decrease in overall pregnancy rate, including a reduced percentage confirmed pregnant after the first service. This infertility and “delayed breeding” are often blamed on the AI technician, a dud bull, hot weather, or fescue when it is actually the BVD virus causing failure to conceive and early embryonic death.
b. Fewer live calves- BVD virus infection during pregnancy may result in abortions, mummies, stillbirths, neonatal deaths, and weak newborns that die shortly after birth.
2. Physical abnormalities including “dummy calves” that cannot nurse, eye defects, and cleft palates in newborns if dams are infected with the virus during mid-pregnancy.
3. An increased number of calf death losses pre-weaning due to pneumonia or scours.
It is important to realize that BVD virus in a herd may not have easily recognizable “classic signs” such as an increased number of abortions or birth defects. It may simply look like fewer mature cows pregnant at pregnancy check, finding cows open that should be calving, or more disease and death loss in pre-weaned calves than usual.
There are two types of BVD virus infection described in cattle; 1) “acute” or “transient” infection and 2) “persistent” infection (PI). An acute BVD viral infection usually lasts 10 days to 2 weeks and symptoms may range from severe to unnoticed, depending on the age of the affected animal and its level of immunity. In an adult unvaccinated (or poorly vaccinated) animal, the virus typically does not cause outward signs of sickness. However, the virus attacks reproductive tissues (ovaries of females, testes in males) resulting in infertility. Bulls may experience prolonged testicular infections. In pregnant cattle, the virus crosses the placenta to the developing embryo or fetus, causing several types of reproductive wastage or malformations, depending on the stage of fetal development when infection occurred.
Acute BVD virus infection in a susceptible calf may result in disease manifestations ranging from mild to severe disease and death. The BVD virus first attacks the immune system where it destroys the production of disease-fighting white blood cells, causing severe immunosuppression. Secondly, it can work synergistically with other viruses to make them more aggressive and deadly. This combination attack results in increased disease and mortality risk in pre-weaned calves exposed to the virus and a substantial risk of respiratory disease and death loss in calves post-weaning.
As mentioned previously, the outcome of acute BVD infection in the cow herd may be observed by a producer as infertility, delayed breeding, abortions, malformed calves, and neonatal death loss. Acute BVD virus infections in pre-weaned calves are recognized by the increased amount of sickness and death loss. What cannot be observed is the 2nd type of BVD infection, the development and birth of persistently infected (PI) calves. If an unvaccinated pregnant cow or heifer is infected with the BVD virus between 42-125 days (about 4 months) of gestation, the virus crosses the placenta and infects the fetus during a critical stage in its immune system development. The virus incorporates itself into the developing fetus, so the immune system does not recognize the virus as a foreign invader. When this calf is born, it is “persistently infected” with the BVD virus (known as a “PI” calf) and is a lifetime “carrier” and “shedder” of massive amounts of virus particles from all its bodily fluids including saliva, nasal discharge, feces, and urine. Those PI calves that survive past sexual maturity will also shed virus particles in milk, semen, uterine secretions, and aborted membranes. A PI cow will always have a PI calf although less than 10% of PI calves come from PI positive dams. One PI calf born on a cow/calf operation usually means there will be additional disease problems within that calf crop. Any fetus infected with BVD later in gestation (150 days (about 5 months) or more) while in the uterus will not become a PI but still will not be “normal”. The virus commandeers certain cell types to produce more virus particles that would normally be used for critical fetal development. This results in destruction of endocrine tissue and may destroy 20-80% of the thymus gland, an important driver of immune function in young calves. These calves will have increased respiratory disease, poor growth and performance, and if they reach sexual maturity, more reproductive issues. Therefore, the reason pre-weaned calves in the same field with a PI calf typically exhibit more sickness and death loss (scours, “summer pneumonias”) is two-fold; 1) due to ongoing immune system suppression from constant BVD virus exposure coming from the PI calf and 2) due to a damaged immune system from BVD virus infection while in utero.
The key to transmission of the BVD virus within and between herds and virus persistence year after year is the PI animal. Ingestion or inhalation of the virus by direct contact with body fluids or aerosols from PI cattle are the main and most important source for BVD virus transmission. In addition, any virus deposited in watering troughs, feed troughs, round bales of hay, cattle trailers-virtually everywhere the PI animal goes-can be picked up by the other cattle in the herd, either by mouth or nose. Importantly, a PI calf shedding virus in the pasture during breeding season will expose many (if not all) of the cows/heifers to the virus during the highest risk time for development of the next generation of PI calves that will be born during next year’s calving season. Acutely infected cattle shed virus particles too but at a significantly lower rate and shorter length of time. A normal calf infected with the BVD virus sheds approximately 10,000 virus particles per day and recovers in 10-14 days. In comparison, a PI calf sheds 10 MILLION virus particles every day of its life. This is why detection and removal of PI animals is crucial to BVD virus control.
Once a producer receives the diagnosis of BVD virus infection in the herd, the first question asked is how did it get here? Research has proven that the #1 cause of BVD virus entering a herd is through the purchase of pregnant females, especially first calf heifers, without properly testing for the virus. The testing strategy must include testing every purchased pregnant female for BVD and also testing her newborn calf for “PI” status. It is not enough to test the dam and ignore her unborn calf because it may not have the same BVD status as its dam and cannot be BVD tested until it is born! It is recommended to calve out purchased pregnant females away from the home herd and test their calves for BVD virus as soon as possible. In addition, don’t allow these cow/calf pairs to have contact with the home herd until each new cow and her calf has a BVD negative test result. Although a pregnant cow tests negative for BVD, always bear in mind she can still be carrying a persistently infected (“PI”) calf that will test positive. Over 90% of PI calves are born from BVD negative dams.
All newly purchased cattle, regardless of age or pregnancy status, should be tested for BVD-PI, vaccinated appropriately, and isolated away from the home herd at least 2 weeks. Other sources of the BVD virus in a cow/calf herd include introduction of new breeding bulls, a calf purchased from a sale to graft on a cow, or feeder calves purchased at auction and brought home to the farm have the potential to be acutely or persistently infected. Even show cattle that are vaccinated and have tested negative for BVD-PI may become acutely infected with the virus and can bring the virus back when they return from fairs and exhibitions. This is why quarantine for all animals arriving to the farm away from the home herd for at least 2 weeks with no nose-to-nose contact or shared water sources is crucial to preventing virus spread. In the same manner, herds with fence line contact with feeder calves or other cattle frequently traded may result in exposure to the BVD virus if allowed to touch noses or share water. There are other minor sources of transmission including fomites (needles, OB sleeves, nose tongs) and vectors including stable flies and horse flies. Other species including sheep, pigs, alpacas, deer, and goats can also carry the virus to cattle.
Although vaccination is a key component in BVD virus control, just vaccinating the herd annually without practicing excellent biosecurity and surveillance for PIs will not keep this virus from gaining entry to the farm. Vaccines against BVD virus (including those with Fetal Protection claims or “FP” vaccines) will reduce the chance of fetal infection and PI development but this is an extremely high bar for any BVD vaccine to achieve. The question of whether to use modified live or killed vaccine is not an easy one to answer. Many popular beef magazines offer articles concerning what types of vaccines work “the best” or are “safest” according to the latest research. The truth is, there are tradeoffs when it comes to vaccine selection. Modified live vaccines (MLVs) offer better and more effective pregnancy protection but the IBR portion of the vaccine can impact conception rates if given too close to breeding season. If using timed artificial insemination (AI), experts recommend administering MLV vaccines at least 45 days pre-breeding to allow 2 estrus cycles prior to insemination. In addition, MLV vaccines can cause abortions if given to pregnant cattle without strict adherence to label directions. Killed vaccines, on the other hand, are safer but are not as good at preventing fetal BVD infection. A herd with excellent biosecurity and at exceptionally low risk can err on the side of safety and use killed vaccine. However, herds that purchase animals including replacement females and/or bulls, herds near stocker cattle or unvaccinated neighboring cattle, show cattle herds, herds with frequent deer contact, or any other probable exposure should err on the side of efficacy and choose modified live. If breeding occurs yearround so MLVs are not an option, an alternative is to administer two doses of MLV vaccine to open heifers (at weaning and a second dose 6 weeks prior to breeding) with annual revaccination using a killed vaccine. This combination stimulates excellent protection without the risk of MLVs although this protective response will diminish after several years. Finally, and perhaps most importantly, cattle herds are unique entities with different risks for disease on every farm so work with a veterinarian to choose the right vaccines for the herd.