Beef Cattle Herd Health - Archived

Beef Cattle Herd Health - Archived Articles

UC Davis Veterinary Views: Articles on animal health issues published monthly by Dr. John Maas in California Cattleman, the magazine of the California Cattlemen's Association.

Beef Quality Assurance: What's the Weakest Link?
(PDF: 3pp, 68KB) Nov 2009

Diarrhea in Weaned Calves
(PDF: 3pp, 80KB) Sep 2009

Treating and Preventing Footrot in Cattle
(PDF: 3pp, 76KB) Jul-Aug 2009

Woody Tongue: Recognition, Treatment and Prevention
(PDF: 2pp, 80KB) Jun 2009

Preventing Pinkeye in Your Herd
(PDF: 6pp, 144KB) May 2009

[Spring] Parasite Control for Current Conditions
(PDF: 2pp, 64KB) Apr 2009

Prepare for a Bad Fly Season in 2009: Current Methods For Fly Control In Beef Cattle
(PDF: 4pp, 116KB) Mar 2009

Preventing Damage from Liver Flukes
(PDF: 2pp, 76KB) Feb 2009

Responsible Drug Use & Consumer Confidence in Beef
(PDF: 4pp, 108KB) Jan 2009

Get Ready for Calf Scours
(PDF: 4pp, 88KB) Dec 2008

Sudden Death in Adult Cattle
(PDF: 4pp, 104KB) Nov 2008

Booster Vaccines
(PDF: 3pp, 80KB) Oct 2008

Treating Pneumonia in Beef Cattle
(PDF: 5pp, 128KB) Sep 2008

Pinkeye—Prevention and Treatment
(PDF: 4pp, 164KB) Jun 2008

Fly Control for Beef Cattle—2008
(PDF: 4pp, 112KB) May 2008

Humane Handling and Transport
(PDF: 3pp, 69KB) Apr 2008

Treating and Preventing Retained Placenta in Beef Cattle
(PDF: 3pp, 96KB) Mar 2008

New BVD Vaccines: What's the Story?
(PDF: 2pp, 96KB) Feb 2008

Killer Oak Trees (Oak Toxicity)
(PDF: 2pp, 84KB) Jan 2008

Save an endangered species... your rural veterinarian!
(PDF: 2pp, 116KB) Dec 2007

Coccidiosis in Cattle
(PDF: 2pp, 85KB) Nov 2007

Methods to Prevent Copper Deficiency in Beef Cattle
(PDF: 4pp, 100KB) Oct 2007

Leptospirosis in California Beef Cattle
(PDF: 2pp, 96KB) Sep 2007

Summer Doctoring
(PDF: 4pp, 128KB) Jul-Aug 2007

Anaplasmosis Management
(PDF: 3pp, 102KB) Jun 2007

Fly Control for Beef Cattle—2007
(PDF: 4pp, 124KB) May 2007

Footrot in Cattle
(PDF: 2pp, 84KB) Apr 2007

California's Trichomonosis Control Program: Proposed Changes
(PDF: 3pp, 88KB) Mar 2007

California's Trichomonosis Control Program: The First Three Years
(PDF: 2pp, 84KB) Feb 2007

Trichomonosis Part I: Trichomonosis in Cattle, a Review
(PDF: 4pp, 128KB) Jan 2007

E. Coli O157:H7, Spinach, & Cattle
(PDF: 4pp, 112KB) Dec 2006

Cautions, Precautions, Adverse and Untoward Reactions
(PDF: 2pp, 100KB) Nov 2006

Fall Deworming Considerations
(PDF: 2pp, 76KB) Oct 2006

UC Davis Cattle Health Research to Benefit Cooperator Herds
(PDF: 3pp, 112KB) Sep 2006

Animal Identification: Where Are We Now?
(PDF: 2pp, 74KB) Jul-Aug 2006

Preventing Anaplasmosis
(PDF: 3pp, 28KB) Jun 2006

Fly Control for Beef Cattle, 2006
(PDF: 4pp, 120KB) May 2006

Nitrate Toxicity in Cows with Chocolate Blood
(PDF: 3pp, 116KB) Apr 2006

Will a Wet Year Mean More Problems with Liver Flukes?
(PDF: 2pp, 88KB) Mar 2006

Treatment of Calf Scours
(PDF: 3pp, 108KB) Feb 2006

Antibiotic Choices for Beef Cattle
(PDF: 5pp, 164KB) Jan 2006

Foot and Mouth Disease

Foot and mouth disease is not considered a human health threat. California has not experienced an outbreak of foot and mouth disease since 1929. Yet because of its highly contagious nature and severe economic consequences, the disease is a serious concern in international animal health and a threat to California's beef, dairy and swine industries.

ABOUT THE DISEASE
Foot and mouth disease (FMD) is a highly contagious, debilitating viral disease affecting cloven-footed domestic and wild animals such as deer. Species affected include economically important cattle, sheep and pigs. Because it spreads rapidly and widely, and has grave consequences to animal welfare and international trade, FMD is one of the most feared animal diseases.

FMD can be transmitted to susceptible animals when they are exposed to the following: people wearing contaminated clothing or footwear; infected animals added to a herd or flock; contaminated facilities or equipment on the farm; contaminated transport vehicles; or contaminated water, hay, feedstuffs, hides, or pharmaceuticals. Airborne spread is possible up to 40 miles over land and 180 miles over water.

Current policy for eradication is to establish quarantines, depopulate sick and exposed animals, dispose of animals and disinfect facilities. Vaccination against FMD is considered the last option and is not used except in FMD endemic areas, because vaccination lowers the value of products and limits access to markets.

ECONOMIC IMPACTS
An FMD outbreak would be a potential agricultural disaster. It could cost from $6-14 billion in control costs and lost markets—assuming control was achievable—according to a 1998 UC Davis study projecting estimated economic impacts of an outbreak. Exports would be halted. Movement of animals within the state and the country would be severely restricted. Note that California income in 1998 alone from exports of milk and cream products was $275.1 million and from beef products, $252.7 million. Those exports would stop immediately. Rebuilding farm industries would involve additional expenses and time. Producers and workers in related industries would be affected, including distributors, exporters, packers, retailers and restaurateurs.

WHAT NEEDS TO BE DONE IN THE FACE OF AN OUTBREAK?
FMD must be reported to authorities. Veterinarians are the first to recognize and report FMD to regulatory veterinarians. State and federal agency veterinarians have programs in place to decrease the risk of introduction into the United States and to respond to an outbreak. Authorities require that producers quarantine facilities housing animals suspected of infection with FMD, restrict animal movement on surrounding farms and ranches, and halt exports of animals.

Killing and disposal of affected animals and exposed animals is the accepted method to stop the spread of FMD. Authorities must dispose of carcasses by burial or burning, and disinfect facilities. Restocking is done after the facility has been vacant for a minimum of 30 days, and new animals are closely observed for recurrence of infection.

It is not known how likely an outbreak would be in the United States. Vigilance is critical. There is concern that foreign travelers and visitors from other countries may introduce the disease into the United States without knowing it. When outbreaks occur worldwide, veterinarians and producers should limit foreign visitors to farms to reduce risk of infection. Basic on-farm biosecurity would include disinfectant solutions such as foot baths, disposable boots and disposable coveralls.

VETERINARIANS AND FOOT AND MOUTH DISEASE
Because control is so difficult, preventing introduction of the disease is crucial. Veterinarians assist producers in facing the challenge of recognizing and reporting FMD and would be called upon to participate in the depopulation, disposal, disinfection and evaluating facilities for restocking.

The UC Davis School of Veterinary Medicine plays a key role in being prepared for FMD and other kinds of infectious diseases outbreaks in the following ways:

Educating veterinarians and providing faculty expertise.
Training veterinarians to recognize emerging and foreign animal diseases, manage herd health and work on other issues in livestock and poultry medicine.
Providing information to veterinary practitioners on infectious diseases through online immediate access (foot and mouth disease is included in the following article: Review of Clinical Signs of Foreign Animal Diseases Which a Mixed Veterinary Practitioner Might Encounter on a Dairy).
Supporting surveillance and diagnostic programs through the California Animal Health and Food Safety Laboratory System (CAHFS). Collaborative efforts with state and federal agricultural agencies to recognize the disease, report it immediately and cooperate in emergency response activities.
Preparation of key faculty (11 individuals) through training at Plum Island Animal Disease Center to recognize FMD. CAHFS faculty stand ready to assist with response if FMD occurred in California, and selected faculty members participated in an emergency response exercise led by CDFA and the USDA in 1998.
Conducting of research on infectious diseases--causes, impacts, treatments, and prevention
Helping to ensure food quality, food safety and availability of low-cost food.

Bovine Trichomonosis: Essential Facts and Testing

What is bovine trichomonosis?

Bovine trichomonosis (a.k.a. trichomoniasis) is an important cause of economic loss in cattle operations that use natural service. Surveys in California beef cattle operations have shown that more than 15 percent of herds had at least one infected bull. This disease is caused by a protozoan organism called Tritrichomonas foetus. This organism lives in the folds of the bull's penis and internal sheath. In cows this organism colonizes the vagina, cervix, uterus and oviducts.

How does it get transmitted?
Trichomonosis is a venereal disease of cattle. It is transmitted from cow to cow by a bull or, in rare cases, by contaminated semen or insemination equipment or nonhygienic artificial insemination (AI) procedures.

How does it affect cattle?

The most common signs in an infected herd are:
Early abortion (too early to find an aborted fetus).
Repeated breeding resulting in long breeding seasons.
A wide range of gestational ages at pregnancy check.
Pyometra (pus-filled uterus) in about five percent of cows.
In first-time infected herds, it is common to end with a 50 to 70 percent calf crop strung out over three to eight months.
Bulls show no clinical signs.
Cows can commonly clear the infection within a few months, however, infection in bulls over 4 years of age is usually permanent and is the main source of transmission from one breeding season to another.

How can you test your herd for infection?
Testing for Tritrichomonas foetus is usually done on breeding bulls by performing a scraping of the penis and prepuce in order to obtain a preputial (internal sheath) fluid sample, and inoculationg the sample into special culture media. If one bull is found positive, you should assume that the whole herd is exposed. Studies of positive bulls have shown that this culture method will miss about 10 to 20 percent of infected bulls if the test is performed only once. So, if no infected bull is found on the basis of one culture of all the bulls in the herd, then we can be 80 to 90 percent sure that the herd is "clean."

How can you treat infected herds?
The disease is self-limiting in cows, as opposed to bulls, that will be permanently infected. After several heat cycles, most cows and heifers clear the infection, but this may take months.

There is a vaccine available for Tritrichomonas foetus (Trichguard or Trichguard Plus [Ft. Dodge]). The vaccine helps cows/heifers to clear the infection in a matter of weeks (vs. months in unvaccinated cows). In most cases, it does not prevent infection. No vaccine efficacy has been shown in bulls. There is no approved treatment for infected bulls.

How can you prevent the disease in your herd?

Use young, fertile bulls or artificial insemination (AI).
Culture new bulls at breeding soundness exam time.
Keep a closed herd and test any animal that you buy.

How can you control the disease in your herd?
If one of your bulls is positive for trichomonosis, it is recommended to cull all bulls and vaccinate all females twice, one month apart. The best option to control trichomonosis is to use artificial insemination. If you want to keep your bulls, you can vaccinate all females annually, but it would b e better to cull all bulls and open cows before next season.

An alternative, if you don't want to cull all bulls, is to sample them at least three times at weekly intervals. With three negative tests, we will be 99 percent confident that a bull is negative. Given the sensitivity of the culture diagnostic test, the table below will give you an idea of the confidence you should have in a "negative" bull, depending on how many times he is tested.

How sure can you be that your bulls are clean after a negative test result?
First test - date: 80% sure
Second test (one week later) - date: 96% sure
Third test (one week later) - date: 99% sure