Cattle Notes from Dr. Mick Harding

Clostridium perfringens Type A

Clostridium perfringens Type A is becoming a major concern among cow/calf, stocker, and feedlot operations worldwide. Most producers are more aware of the Type C & D form of the disease. However, Type A is diagnosed approximately 70% of the time when Clostridial enteric disease is suspected. Type A is ubiquitous(everywhere) in nature and is also part of the normal intestinal flora. It lacks a system to make its own nutrients so it uses toxins to attack host cells causing them to liberate nutrients the Clostridium needs to grow. This process causes the disease.

The disease process to the producer is usually seen as sudden death and the animal may or may not appear bloated. The classic "C & D" or "overeating". If the animal is found sick it may have the humped up back and/or be bloated or abdominally distended. Some veterinarians contend that calves with Type A may survive longer than a calf with Type C before they die. In my experience, Type A is usually a sudden death and may involve adult cows. Necropsy will show usually a diffuse hemorrhagic small bowel whereas Type C tends to be more segmental. Diagnostic lab confirmation is needed to tell whether you are dealing with a Type A, C, D, or E.

Prevention and/or control of Type A can be done by giving a conditionally licensed vaccine(Clostridium perfringens Type A Toxoid from Novartis). This can be given to pregnant cows prior to calving to help calves acquire immunity through colostrum. Feedlots can give this product when they are giving other vaccines or implanting. This Type A is grown under specific growth conditions to provide high levels of the alpha toxin antigen which is not found in traditional 7-way or C & D vaccines. The toxin is then inactivated to make the toxoid.

There are currently many autogenous Type A vaccines available from many vet clinics. Some may work but most probably do not. The autogenous products cannot guarantee that the alpha toxin is produced when the Clostridium grows as it may not be grown under optimal conditions to promote toxin production. If the current Type A product you are using appears to be working I would not automatically change, but I would wonder if you needed the vaccine to begin with. I, also, would not start vaccinating with a Type A product without proper lab confirmation of a diagnosis.

Another scenario with autogenous vaccines in general is there legal distribution. Autogenous vaccines are custom made for a specific herd using viruses or bacteria isolated from that herd within the last 24 months. They can only be used in the herd of origin, or with permission in adjacent and non-adjacent herds. For use in adjacent and non-adjacent herds, the use must be justified(lab confirmation of diagnosis and no currently approved product that appears to work on the market). This use also requires approval from the USDA Center for Veterinary Biologics and the State Veterinarian before it is used. Some vets have gotten into trouble for not gaining the proper permission. For this reason I always recommend the Novartis product after lab confirmation of my diagnosis before using autogenous products for Type A.

Mycoplasma in Beef Cattle

Introduction

  • First isolated 100 years ago
  • One strain causes Contagious Bovine Pleuropneumonia (eradicated in U.S)
  • Current manifestation first reported in U.S. in 70's
  • Now disease is widespread and individual cases can occur in any herd
  • Severe outbreaks can be devastating
  • In a 2006 study, Mycoplasma bovis was present in 46% of cattle with normal lungs, 85% of cattle with acute fibrinous pneumonia, and 98% of cattle with chronic pneumonia
  • It grows slowly and requires special media to grow
  • Primarily affects stocker and feeder calves but occasionally found in nursing calves in cow-calf operations

Transmission

  • Many species but Mycoplasma pneumonia is most commonly caused by M. bovis
  • Most likely spread is from calf to calf
  • Direct contact
  • Thru air when closely confined
  • Drenching and balling guns
  • Only survives for short period in environment so contaminated barns, feed troughs, trucks, etc. not that impt.
  • As long as Mycoplasma remains in the upper respiratory tract it does not cause disease
  • When the bacterium enters the lung it causes a pneumonia different from classic shipping fever
  • From the lung it can travel thru the bloodstream where it is capable of entering the joints, organs, and nerves
  • In beef cattle, Mycoplasma most commonly goes to the joints causing a crippling arthritis and tendon inflammation
  • Can also infect ears, eyes, udder, and genital tract

Clinical Signs

Pneumonia

  • Mycoplasma bovis can, by itself, cause respiratory disease
  • Usually an initial stressor causes calves to develop BRDC, and Mycoplasmosis develops 7-14 days later
  • BVDV has been shown to suppress the immune system predisposing cattle to M. bovis and other respiratory diseases
  • Mycoplasma weakens the cattle's immune system and inhibits the respiratory tract's own defenses against disease
  • There are no toxins produced so these calves initially do not look as sick as calves with Mannheimia hemolytica
  • Nearly 100% of calves will be infected within two weeks of exposure

Common Clinical Signs

  • Harsh hacking cough
  • Low grade fever
  • Mildly increased respiratory rate
  • Mild depression
  • Runny eyes
  • Alert and have a fair appetite

However, if they are not treated early condition will worsen dramatically and be much harder to treat. It may take 7-14 days after respiratory tract is infected before calves show dramatic clinical signs, and by this time significant and often permanent lung damage has been done (higher deaths and more chronics)

Necropsy reveals small abscesses throughout the lung (scattered rice appearance) and do not respond well to standard treatments and often relapse up to one month after initial treatment

Arthritis

  • Some calves with pneumonia du to M. bovis will develop a severe arthritis 2-4 weeks later
  • Different strains have different likelihoods of causing joint problems(some outbreaks have many lames while others have none)
  • Affected calves will have swollen joints that are so painful they are reluctant to walk to feed or water
  • By the time joints are involved severe lung damage has probably occurred
  • In rare cases- joint involvement without any signs of pneumonia
  • Knee and stifle most common, but any joints can be involved
  • One or more joints may be involved
  • Inflammation involves the joint capsule and tissues surrounding the joint
  • Cartilage is minimally affected - importantn for prognosis, as even joints that are severely affected often recover

Others

  • Ear infections-dropped ear(s) with draining yellow pus
  • May invade inner ear-head tilt, circling or falling to one side
  • Abortions
  • Infertility
  • Mastitis
  • Inflammation of the eyes in beef cattle

Diagnosis

  • Not able to look at a calf at first pull to tell if Mycoplasma is present
  • Most cases involve an underlying BVD infection causing immunosuppression
  • Definitive diagnosis difficult- can be cultured from nasal secretions and upper airways of normal calves
  • Needs to be recovered from the lungs-requires special culture medium
  • Should be suspected when joint swelling or single drooped ears are noted in a group of calves that have had pneumonia
  • Suspect when pneumonia is unresponsive to treatment
  • Important to remember that some strains of M. bovis may not cause lameness or drooped ears, may be respiratory only
  • In the U.S. M. bovis has become the most common respiratory pathogen of cattle that do not respond well to treatment

Treatment

  • Commonly used antibiotics DO NOT WORK WELL; penicillin, ampicillin, Naxcel, Excenel, Excede, Micotil, A180, Baytril
  • Draxxin (only drug approved) - I would recommend 2 doses 7 days apart
  • Oxytetracycline (LA 200) - Treat every 3 days for 5 treatments
  • Tetradure - 2 treatments 7 days apart
  • Nuflor - Every 4 days for 4 treatments (6 cc.'s/ 100 lbs.)
  • Adspec - Haven't used personally for this, but would have to give daily for 2 weeks
  • Baytril and A180 (may be useful in mixed infections most are) - I haven't had much luck using these
  • Tylosin - 5 cc.'ss/ 100 lbs. daily for 14 days

Two most important factors:

1) Early recognition
2) Prolonged therapy

  • Without extended therapy, 30-70% of the calves can relapse and require treatment again
  • Each time a calf relapses it will have more lung damage and be less likely to recover
  • Current recommendations are to provide continuous therapeutic levels of antibiotics to calves with Mycoplasma pneumonia for 10-14 days
  • CTC in feed- 1 gram/ 100 lbs. for 14 days. I usually follow with .5g/ 100 lbs. for another 14 days
  • Using antibiotics to treat swollen joints is usually unrewarding after pneumonia has been controlled
  • Provide easy access to feed and water
  • May be necessary to run these calves to feed and water several times daily until they have begun to recover
  • Given enough time a large number of these calves will recover
  • It can take weeks to months for the joints to fully recover and the cattle to start gaining weight

Prevention

A large percentage of normal cattle have M. bovis in their upper respiratory tract making it next to impossible for stocker operations to implement biosecurity measures to prevent Mycoplasma from entering as there are many different sources.

  • Cow-calf producers should observe strict biosecurity protocol when bringing in new herd additions
  • Most important-prevent stressors
  • Good vaccination
  • Good nutrition and mineral programs to strengthen immune system
  • Number of cattle received at any one time should not exceed facilities
  • Poor quality or high risk calves should not be acquired unless they can be watched closely
  • Drenching and balling guns should be disinfected between each use
  • Recognize and treat sick cattle early
  • Decreases chronics and deaths
  • Decreases spread among populations
  • Clean waterers in pens after infected group has been removed before new arrivals
  • The vaccines currently available against M. bovis have not been shown to be effective in beef cattle
  • Vaccination has provided best results when used in young calves and two or more doses of an autogenous vaccine were given
  • Use of vaccine on arrival has not shown benefit
  • Usually easier to develop protection against arthritis than pneumonia