Oral and Poster Abstracts

J. Muskens
Animal Health Service Deventer, Deventer, Netherlands
Stillbirth in heifers was an important issue for many Dutch dairy
farmers during the last two decades. A pilot study of 10 dairy herds
with at least 20% of stillbirth of heifers was performed. The study
consisted of extensive post-mortem examinations of one stillborn calf
per herd, blood and urine testing of pregnant young stock at 0.5-2
months before expected calving, and a questionnaire about parturition,
nutrition and management around calving. Nine herds were certified
leptospirose free; one herd was treated with antibiotics. One calf was
BVDV positive at post mortem examination. In none of the calves there
were indications of infections with Neospora caninum or Salmonella
spp., or of a deficiency of iodine. The number of herds with decreased
202 Mycoplasma Diseases in the Bovine: Diagnosis, Prevention
and More
L. Fox 1 , C. Schneider 2 , L. Stipkovich 3
1 Washington State University, Veterinary Clinical Sciences, Pullman,
United States
2 University of Idaho, Moscow, ID, Animal & Veterinary Sciences,
Moscow, United States
3 Veterinary Medical Research Institute of the Hungarian Academy of
Sciences, Veterinary Medicine Research Institute, Budapest,
Hungary
The Mycoplamsa sp. that cause mastitis are simple, cell wall-less
bacteria that can colonize and cause diseases in other extramammary
sites in the bovine. Prevalence of mycoplasma mastitis
appears to be increasing in many locations throughout the world.
Traditionally Mycoplasma sp. mastitis has been considered
contagious pathogens that are transmitted in a fashion that is typical
of other contagious mastitis pathogens (S. aureus and Str.
agalactiae). Such transmission is believed to occur mostly during
milking time, and that introduction of mycoplasma mastitis can
occur through the importation of infected cattle from outside the
dairy. Studies will be reviewed that have indicated that transmission
of Mycoplasma sp. can occur internally. From the extra-mammary
nidus of colonization, Mycoplasma sp. can be transmitted to the
mammary gland, or vice versa. New prevention methods would have
to be developed to counter this mode of transmission. The
established contagious mastitis control practices of employing strict
milking time hygiene that includes post-milking teat asepsis, and of
identification of the infected animals and isolation of those animals
by separation and culling, has been successful and is currently the
method advocated to control mycoplasma mastitis outbreaks. The
fault in this system is that although it controls the outbreaks, it might
not be as effective at preventing the outbreaks from occurring. In
addition to mastitis, Mycoplasma sp. bacteria have been implicated
in a variety of disease conditions in cattle including
bronchopneumonia, septic arthritis, reproductive disorders and otitis
media. The overall annual impact of this etiologic agent on U.S beef
and dairy industries has been estimated to be as high as $100 million.
Calf hood infections may play a role in the transmission of
Mycoplasma sp. in particular, more virulent species such as
Mycoplasma bovis on dairies. Basic mechanistic and applied
Mycoplasma sp. research holds promise for elucidating the
underlying etiology and risk factors associated with calf hood ear
infections. Related areas of research in the U. S. concern the role of
Mycoplasma ovipneumoniae in acute, severe, fatal outbreaks of
respiratory disease in lambs occurring in indigenous native sheep
populations (Ovis canadensis). Emerging evidence indicates that
Mycoplasma sp. may be acting as primary pathogens in these disease
outbreaks.
203 Mycoplasma Bovis Infection of Calves
L. Stipkovits 1 , S. Szathmary 2
Mycoplasma Workshop
blood contents of GSH-Px or copper, or decreased urine contents of
magnesium in young stock was 2, 3 and 2. Five herds had at least one
animal with GSH-Px contents higher than 600 U/g Hb. Five farmers
reported that the afterbirth was delivered within one hour of calving;
four farmers reported that most heifers had retention of the afterbirth.
Five farmers reported an increased mean body condition score of the
pregnant young stock. In 2006 187 stillborn calves were examined post
mortem at the Animal Health Service in Deventer. Of these, 87 calves
had no abnormalities. Signs of asphyxia were diagnosed in 73 calves.
Other diagnoses included congenital defects (n = 8), infections with
BVDV (n = 8) or Arcanobacterium pyogenes (n = 4). Based on these
results, other Dutch field experiences and literature, a possible
approach to dairy farms with an increased numbers of stillborn calves
in heifers will be discussed.
1 Vet.Med.Res.Inst., Mycoplasma, Budapest, Hungary
2 Galen Bio Inc., Mycoplasma, Carlsbad, United States
In cattle, beside Mycoplasma mycoides subspecies mycoides SC,
being present in African and Asian countries, M. bovis is the most
pathogenic species. The infection can be introduced in previously
negative herd by clinically healthy infected animals, by various tools
used in barns, by milk from infected cows and by semen. If the
infected calves are introduced in the groups of negative calves
clinical symptoms of respiratory diseases start to develop. Serouspurulent
nasal discharge can be observed after 4-7 days, increased
rectal temperature, frequent cough, difficulty in breathing and
lethargy develops later after mixing the animals. Over 20% of the
animals in the group can develop mono- or polyarthritis, or otitis, or
meningitis. Weight gain of the diseased calves is decreased
significantly. Mortality due to pneumonia in such infected herd, if
treatment is not performed, can reach 25-30% of calves during first
40 days. Later on animals became asymptomatic, but they carry M.
bovis and can be a source of infection for the other animals. These
asymptomatic animals will still show delayed growth. Body weight
at age 8-10 month is about 100 kg less than the uninfected
animals. Infection with M. bovis through semen results in abortion,
early birth of weak calves, with signs of pneumonia and arthritis.
This can be recorded in few days old calves. About 50% of the
infected cows have retention of embryonic membranes after calving
and develop parenchymatosus mastitis with very high increase in
somatic cell count along with significant decrease in milk
production. Some of the cows also show arthritis. If the milk from
cows suffering from M. bovis mastitis is fed young calves,
respiratory symptoms develop in 3-6 days. If the infection is
introduced through healthy-looking, but infected heifers or cows,
symptoms of the disease (respiratory disease, abortion or mastitis)
develops gradually in relatively fewer animals. Later on the disease
spreads more rapidly. Post mortem examination of young calves died
due to M. bovis infection, inflammation of the trachea, pleuritis and
catarrhal pneumonia of various extensions, enlarged peribronchial
lymph nodes, sometimes inflammation of kidney can be observed. In
the arthritic joint, accumulation of serous-fibrinous exudates,
erosion of the synovial membrane can be detected. Mycoplasmas can
be cultured from several organs.
Key words: cattle, Mycoplasma bovis, isolation, pathology
204 Prevalence of Mycoplasma bovis Infection in French Dairy
Cattle
MA. Arcangioli 1 , MA. Botrel 2 , M. Chazel 2 , E. Sellal 3 , P. Bézille 1 ,
F. Poumarat 2 , D. Le Grand 1
1
Ecole Vétérinaire, Ruminant Mycoplasmosis, Marcy l'Etoile, Lyon,
France
2
AFSSA, Ruminant Mycoplasmosis, Lyon, France
3
LSI, Diagnostic, Lissieu, France
Mycoplasma bovis (Mb) is widely described as a causal agent of
pneumonia in calves and mastitis in dairy cows. Very little information
Mycoplasma Workshop 321