Abortions in cattle Flashcards
Mummification of bovine fetuses has an incidence of
less than 2%.
Breed and previous occurrence are risk factors, with a higher incidence of fetal mummification in Guernsey and Jersey cattle.
In cattle, fetal mummification occurs after what day of gestation?
70 days of gestation, the time of fetal ossification.
Mummification occurs most often between what months of pregnancy?
the 3rd and 8th month of gestation, without any concomitant luteolysis of the CL or opening of the cervix.
After fetal death, the amniotic and allantoic fluids are resorbed, dehydrating the fetal tissues and annex membranes.
Eventually, the caruncles disappear during the dehydration process. The longer the mummified fetus is retained, the dryer, firmer, and more leathery the tissues of the fetus become.
Mummification that produces a dry, stiff fetoplacental unit with no exudate is called
papyraceous mummification, reported in dogs, cat, cattle, buffalo.
In the other type of mummification, known as hematic or chocolate mummification, a viscous adhesive material covers the mummified fetus.
This type has been reported in cattle, buffalo, and dogs.
Fetal mummification is to be differentiated from
fetal maceration, in which the fetus putrefies, in the uterine cavity, in the presence of bacteria and oxygen originating from the open cervix.
Etiology for fetal mummification.
Several potential causes for this condition have been proposed:
bovine viral diarrhea (BVD),
leptospirosis and
mold,
Neospora caninum;
mechanical factors, such as compression and/or torsion of the umbilical cord; uterine torsion;
defective placentation;
genetic anomalies;
abnormal hormonal profiles; and chromosomal abnormalities.
However, a definitive etiology is rarely established, because of tissue degeneration.
Clinical findings in fetal mummification.
A majority of diagnoses of suspected mummification (63%) are established by veterinarians after the farmer notices that the cow’s abdomen is unusually small for the given stage of pregnancy.
Mummies stayed in utero until they were removed, with the presenting complaint usually occurring several days past the calving date.
Therefore, no significant systemic or other type of illness is observed in cows except for spontaneous abortion, which may or may not occur.
Diagnosis of fetal mummification.
Transrectal palpation and ultrasonographic examination show the mummified fetus as a compact, firm, and immobile mass without placental fluid or placentomes.
The ultrasound examination reveals the absence of a heartbeat.
The general physical examination of the dam appears normal, although decreased milk production and weight loss have been observed in rare cases (but may have been attributable to other factors).
Treatment of fetal mummification.
There is a systematic approach to treating pregnant cows diagnosed with fetal mummification.
Prostaglandins (PGs; PGF2α) are the primary and most effective treatment.
In most cases, the mummified fetus will then be expelled from the uterus.
All treated cows should be assessed via transrectal and vaginal examination about 5 days after the first injection of PGF2α, in order to check for the presence of CL, cervical dilation, and the fetus in the vagina.
After expulsion of the fetus, a uterine lavage should be performed to remove fetal and placental debris, and the cow should be rapidly induced into estrus and inseminated.
If the cow does not respond to two injections of PGF2α after 5 days, a decision must be made: proceed with an hysterotomy (laparotomy) or continue medical treatment with a combination of PGF2α and PGE2..
Define abortion in cattle.
Disruption of pregnancy, followed by resorbtion of the fetus, expulsion of the fetus, mummification, maceration or putrification of the fetus.
Line between abortion and premature birth is
210 days of pregnancy.
If before, we will continue with present lactation, if later then calculation of new lactation.
If occurrence on the second half of the pregnancy increase in production may follow.
Causes of abortion in cattle.
May vary a lot (dependent on region, herd situation, feeding and management, infectious disease situation etc.)
genetic factors, trauma, iatrogenic from palpation, temperature, uterine health etc.
Very often we find a reasons only in 40% of cases.
High cost of laboratory investigations + low outcome.
Most of the laboratory investigation results (90%) will say that the reason is infectious disease.
Infectious abortions in cattle.
1. Late pregnancy stage
Name 7 agents.
Bovine herpesvirus 1 (IRT)
Brucellosis
Leptospirosis
Listeriosis
Salmonella abortion:
S. dublin S. typhimurium
Mycotoxicosis
Neosporosis
Describe Bovine herpesvirus 1 (IRT) abortion in cattle.
After 4 months of pregnancy; embryonic mortality, stillbirth, weak calves, reproductive problems in the herd.
Laboratory diagnosis: placenta normal, changes in fetal organs, isolation from placenta and fetal lungs.
Describe Brucellosis abortion in cattle.
Mostly after 5 months of pregnancy. In the herd: lame cows, mastitis, orchitis.
Laboratory diagnosis: Main changes in placenta and placentomes. Histologically endometritis and placentitis.
Also detection of B. Abortus from fetal lungs, abomasum or placenta.
Describe Leptospirosis abortion in cattle.
L. interrogans (L. hardjo)
Infertility abortion from 4 months of pregnancy until the end of pregnancy, weak calves.
Hemoglobinuria, icterus, anemia, fever, mastitis.
Laboratory diagnosis: fetus yellow (icterus), swollen.
Isolation from fetal liver, kidneys and brain (Usually not tho, because time consuming). Serological investigation from the blood is better.
Describe Listeriosis abortion in cattle.
L. monocytogenes
Abortions during last 2 months of pregnancy. Often no clinical signs in mother. Very seldom fever, endometritis.
Laboratory: liver white-gray lesions up to 2 mm. Histologically placentitis and endometritis. Best to take cultures from aborted fetuses.
Describe Salmonella abortion in cattle.
S. dublin S. typhimurium
Sporadic cases, every stage of pregnancy, characterized by placentary necrosis, edema and bleeding.
No specific clinical signs in mother. Stillbirth and perinatal septicemia.
Laboratory: placentitis, autolysis of the fetus. Isolation from placenta or from fetal tissues (fluoresence antibody staining). Serological tests for mother.
Describe Mycotoxicosis abortion in cattle.
Aspergillus, Absidia, Mucor, Rhizopus, Candida, Mortirella
Abortions during the last trimester of pregnancy. Usually no clinical signe before or after abortion.
Placentitis togther with edema of fetal membranes and necrosis. Fetus normal, but histologically changes in lungs (bronchopneumonia).
In case of Aspergillosi,s fetus dehydrated, skin lesions (25% of cases). Placenta thicken ed and leathery.
Describe Neosporosis abortion in cattle.
Neospora caninum
Definitive host, dog. Horizontal and vertical transmission (oocytes from dog feces).
Most of abortions at the middle of pregnancy.
Laboratory: aborted fetuses. Seroepidemiological investigations at the herd level.
Changes in cotyledons (white up to 2mm necrotic areas and calcification, pneumonia, myocarditis, hepatitis).
Infectious abortions in cattle.
2. Earlier stages of pregnancy
Name 2 agents.
Campylobacteriosis
Mycoplasmosis
Describe Campylobacteriosis abortion in cattle.
Campylobacter fetus spp. veneralis causing temporary infertility or earlier embryonic mortality.
Also technically possible sporadic abortions from 4th up to 8 months of pregnancy.
Usually the problem in the herd is infertility and repeat breeding.
Describe Mycoplasmosis abortion in cattle.
Mycoplasma bovigenitalium (granulatory vulvovaginitis and endometritis) and Mycoplasma bovis (mastitis and abortion)
Placentitis and fetal pneumonia.
Isolation from vagina, also in healthy animals (usually less than 1%), M. bovigenitalium up to 12% in healthy animals.
Infectious abortions in cattle.
3. To affect any stage of pregnancy
Name 2 agents.
BVDV
Histophilus somni
