– Dr. Lee Jones, DVM, Associate Professor, Department of Population Health, Food Animal Health and Management, Tifton Diagnostic and Investigational Laboratory

I’ve gotten several calls this fall asking about using modified live virus (MLV) vaccines in beef herds. Though modified live virus vaccines have been around for years and have been approved for use in adult cows for about 20 years there’s still a lot of confusion about using them.

First, I need to explain what is meant by MLV vaccines. The vaccines that contain Bovine viral diarrhea virus (BVD types 1 and 2), infectious bovine rhinotracheitis or also bovine herpesvirus type 1 (IBR), Bovine respiratory syncytial virus (BRSV) and parainfluenza 3 (PI3) come in 3 types – modified live, killed or combination (chemically altered). When we refer to ‘modified’ live or killed we are referring to virus vaccines. Not 7 way Clostridia (also called ‘blackleg’) or pinkeye vaccines or other bacterin or toxoid type vaccines. While there is a live bacteria vaccine for respiratory protection, it’s the virus part of the vaccine that causes the controversy. All MLV require mixing and they are clearly labeled on the front of the box MODIFIED LIVE VIRUS. The virus in these vaccines is alive and replicates in vaccinated animals causing a mild version of the disease. That’s how MLV vaccines work.

Why the controversy?

MLV vaccines can cause abortions if used in pregnant cows or heifers and can delay . . .

Continue reading Doc, how do I use a modified live vaccine in my cows?

– Dr. Michelle Arnold, UK Veterinary Diagnostic Laboratory

Figure 1: Anaplama marginale organisms (small purple dots) in the red blood cells (larger pink circles)

What is Anaplasmosis? Anaplasmosis is a disease caused by Anaplasma marginale, a bacterial organism that invades cattle red blood cells (Figure 1) and causes severe anemia, often resulting in death. In Kentucky, the disease affects adult cattle, typically in the fall of the year with most cases occurring from late September through the first 1-2 weeks of November.

What are the symptoms of anaplasmosis? This organism causes anemia in adult cattle which means there is an abnormally low number of red blood cells circulating in the bloodstream. Lack of red blood cells results in oxygen deprivation to the vital organs, but symptoms are not noticed until 40-50% of red blood cells are destroyed. Infected cattle will show signs of weakness, lagging behind the herd, staggering, rapid breathing and sometimes foaming from the mouth. Affected cattle quit eating, have a fever and may appear to rapidly lose weight. Most become very aggressive due to lack of oxygen to the brain. Mucous membranes will appear pale early in the course of disease and progressively turn yellow in color due to jaundice. Death can be sudden, especially with exercise, or cattle may be found dead with no prior symptoms. Typically, several adult animals in a herd will die within Continue reading →

– Dr. Michelle Arnold, UK Veterinary Diagnostic Laboratory

Office of the State Veterinarian is warning beef producers to look for signs of Theileria infection (“theileriosis”) in cattle, with two confirmed cases in beef cattle recently reported in Kentucky. Theileria orientalis Ikeda is a microscopic protozoan parasite that infects the red blood cells of cattle, causing anemia. The disease is primarily transmitted by the bite of an infected Asian Longhorned Tick (Haemaphysalis longicornis) or by blood transfer through the use of contaminated needles and equipment. The tick can feed on many animal species, including humans, but the blood parasite only affects cattle. Once a cow is infected, it may take 1-8 weeks before she shows symptoms of disease.

Figure 1: Three life stages of the Asian Longhorned tick sized relative to the head of an insect pin. Nymphs and adults can transmit Theileria to cattle. Photo used with permission from Dr. Matt Bartone, NC State

There is a spring peak in disease incidence in March-April and a fall peak in September-October. There is no effective treatment for sick cattle or vaccine to prevent infections. However, once infected, cattle become carriers and are protected from new infections. There are no recognized long-term health or production effects from persistent infection. Theileria is not a public health concern and contact with affected cattle doesn’t pose a Continue reading →

– Chris Penrose, Professor & Extension Educator, Agriculture & Natural Resources, OSU Extension, Morgan County

The Asian longhorned tick attacks wild and domestic animals and humans. Photo by Anna Pasternak, UK entomology graduate student.

I became disheartened a few weeks ago after I sent a bunch of ticks to a lab on campus to get identified and they confirmed what I feared: that we have the Asian Longhorned tick here in Morgan County. If I am correct, that makes five types of tick we likely have present in the county and many parts of Ohio. Ticks can give us Lyme Disease, Anaplasmosis, Rocky Mountain Spotted Fever, and a disease that makes us allergic to red meat.

The Asian Longhorned tick (ALT) was found last year in a couple of Ohio counties and the populations of ALT became so high on some cows that they died. That scares me. The good news is there is a team of professionals from OSU, Ohio Department of Agriculture, Ohio Department of Health and United States Department of Agriculture that is on top of this and have been very responsive.

What do we know? They are asexual, meaning they do not need a mate to reproduce. Each tick can lay up to 2000 eggs. They move slowly so the spread is very slow unless they Continue reading →

– S. L. Boyles, L. J. Johnson, W. D. Slanger, B. J. Kreft, and J. D. Kirsch, originally published in the Canadian Journal of Animal Science

Twenty-six of 52 heifers with an average liveweight of 700 pounds were dewormed by intraruminal injection of oxfendazole and placed in drylot on January 31. The other 26 animals served as controls. All heifers were pastured starting on June 14 and the treatment heifers were dewormed in the same manner as at the start of the experiment on July 1 and July 31.

The groups started out with similar total worm eggs per gram of fecal sample, but the dewormed heifers had fewer counts each month thereafter. The drylot average daily gain of the treated heifers was higher (P = 0.01) and less variable (P = 0.12) and by May 29 these animals were heavier by 26 pounds (P = 0.10). The treated animals did not gain as fast on pasture (P = 0.20), but the gain continued to be less variable (P = 0.09). Age at puberty was not different. Number of open heifers in the treated group was 4 vs. 15% for the control group (P = 0.18).

Deworming resulted in faster feedlot gains and more uniform gains during both drylot and pasture.

– Tim McDermott DVM, OSU Extension Educator, Franklin County (originally published in Farm and Dairy)

There are some changes coming to the availability of over-the-counter antibiotics that the livestock producer will want to familiarize themselves with soon in order to make sure they are properly prepared before the changes are implemented in 2023.

What is being implemented is the Food and Drug Administration’s guidance for industry (GFI) No. 263 titled “Recommendations for sponsors of medically important antimicrobial drugs approved for use in animals to voluntarily bring under veterinary oversight all products that continue to be available as over-the-counter.”

The reason for this change is to make sure that there is veterinary oversight of medically important drugs to human medicine and to address the growing resistance of antimicrobials in human medicine by multiple bacteria that have Continue reading →