How to Treat Mastitis in Beef Cattle

Given the low diagnostic success charge per unit, the loftier cost of laboratory work, and the low turn a profit margin in both the beef and dairy industries, veterinarians should not attempt to make an etiologic diagnosis in every abortion. Instead, veterinarians should become concerned if fetal loss is >3%–5% per year or per month.

The bodily incidence of abortions in cows due to genetic factors is unknown. Some genetically acquired abortions may not take phenotypically recognizable lesions. Nearly lethal genes crusade early abortion or early embryonic death.

Vitamins A and Eastward, selenium, and fe accept been implicated in bovine abortions, only documentation based on experiments is available merely for vitamin A.

Heat stress causes fetal hypotension, hypoxia, and acidosis. High maternal temperature due to fever may be more important than environmentally induced heat stress.

Although severe trauma may rarely effect in ballgame (the bovine fetus is well protected by the amniotic fluid), farmers undoubtedly blame too many abortions on the cow "getting bumped."

A number of toxins can cause abortion in cows. Ponderosa pine needles tin can cause abortion if ingested in the last trimester; the cows may become moribund subsequently commitment and hemorrhage excessively. The main abortifacient compounds in Ponderosa pine needles are isocupressic acid and labdane resin. Locoweed (Oxytropis or Astragalus sp) contains an indolizidine alkaloid that tin can bear on the corpus luteum, chorioallantois, and neurons, resulting in ballgame or deformities. Broomweed (Guttierrezia microcephala) ingestion can also cause ballgame, as can coumarins from rat poison Overview of Rodenticide Poisoning in Animals Through centuries past, a variety of methods, active ingredients, formulations, and control measures take been used for rodent pest control. These efforts become more apparent as urban areas... read more , many grasses, or moldy sweet clover Sweetness Clover Poisoning in Animals Melilotus spp (sweet clover). In the 1920s, cattle in N America developed a fatal hemorrhagic illness. Diverse causes, including pathogenic organisms and nutritional deficiencies... read more . Sodium iodide, IV, has been contraindicated in pregnant cows, but no abortions or adverse effects occurred in meaning cows treated with a single high dose in some studies. Mycotoxins Overview of Mycotoxicoses in Animals For discussion of mycotoxicoses in poultry, meet Mycotoxicoses in Poultry. Acute or chronic toxicoses in animals can outcome from exposure to feed or bedding contaminated with toxins produced... read more , especially those with estrogenic activity, have been implicated in bovine abortions. Nitrates or nitrites have also been incriminated, but experimental testify is controversial.

Bluetongue Bluetongue is acquired by an Orbivirus with 24 serotypes and is transmitted by biting midges of the genus Culicoides. Historically, bluetongue occurred from approximately latitude 35°S to 40°N, except in the western USA, where it occurs to 45°N. Afterward introduction of an attenuated, alive virus serotype ten vaccine in the 1950s, abortion, mummification, stillbirth, and the nativity of alive offspring with CNS malformations occurred in cattle and sheep. Since then, multiple bluetongue serotypes have been identified equally causes of like reproductive losses in cattle and sheep. Attenuation of bluetongue virus can increase its ability to cross the placenta. At that place is evidence that earlier 2007, reproductive losses were caused by attenuated bluetongue vaccine viruses, either past vaccination of significant animals or past spread of vaccine virus in nature by Culicoides spp.

In 2006, serotype 8 bluetongue virus appeared, spread, and became endemic across northwestern Europe (north of 50°N), where bluetongue was previously unknown. Showtime in 2007, abortions and nascency of "dummy" calves with brain malformations occurred in bluetongue-infected herds; affected calves were documented to have been infected in utero. Since so, many such cases have been reported.

Diagnosis is by identification of precolostral antibodies to bluetongue or identification of the virus by PCR. Brain, spleen, and whole blood are the preferred samples from fetuses and neonates for PCR. Control of bluetongue is by vaccination and direction procedures to reduce exposure to biting midges. Modified-live and inactivated vaccines are available, but their availability and use varies betwixt countries.

The pathology of BVD in the developing fetus is complex. Infection before insemination or during the first 40 days of pregnancy results in infertility or embryonic expiry. Infection between 40 and 125 days of pregnancy results in birth of persistently infected calves if the fetus survives. Fetal infection during the period of organogenesis (100–150 days) may consequence in built malformations of the CNS (cerebellar hypoplasia, hydrancephaly, hydrocephalus, microencephaly, and spinal string hypoplasia). Congenital ocular defects have also been seen (cataracts, optic neuritis, retinal degeneration, microphthalmia). Subsequently 125 days of gestation, BVD may cause ballgame, or the fetal allowed response may clear the virus.

Diagnosis is made via identification of BVD virus by means of isolation, immunologic staining, PCR assay, or detection of precolostral antibodies in aborted calves. The virus is nowadays in a wide multifariousness of tissues, just the spleen is the tissue of choice for testing. Increasing BVD antibody titers in aborting animals or herdmates is diagnostic for recent infection. BVD virus is immunosuppressive and is found in many fetuses with infections caused by other agents (eg, bacteria, Northward caninum). Outbreaks of abortions by organisms that typically cause sporadic abortion should raise suspicion for possible concurrent BVD virus infection.

Prevention should focus on removal of persistently infected cattle and herd vaccination.

Brucellosis Brucellosis in Large Animals (Bang's illness) is a threat in about countries where cattle are raised. In the USA, active control programs, including test, slaughter, and heifer vaccination, have profoundly decreased its incidence. Brucellosis causes abortions in the 2d half of gestation (usually ~7 months), and ~80% of unvaccinated cows in later gestation volition abort if exposed to Brucella abortus. The organisms enter via mucous membranes and invade the udder, lymph nodes, and uterus, causing a placentitis, which may be acute or chronic. Abortion or stillbirth occurs ii weeks to five months after initial infection. Affected cotyledons may be normal to necrotic, and red or yellow. The intercotyledonary area is focally thickened with a wet, leathery appearance. The fetus may exist normal or autolytic with bronchopneumonia. Diagnosis tin can be made by maternal serology combined with fluorescent antibody staining of placenta and fetus or isolation of B abortus from placenta, fetus (abomasal contents and lung), or uterine discharge. Prevention is past calfhood vaccination of heifers.

Brucellosis is a serious zoonosis and a reportable disease, and the appropriate authorities should be contacted.

Campylobacter fetus venerealis causes venereal disease that usually results in infertility or early embryonic death but occasionally causes abortion betwixt 4 and 8 months of gestation. C fetus fetus and C jejuni are transmitted by ingestion and subsequent hematogenous spread to the placenta. Both crusade desultory abortions, ordinarily in the last half of gestation. The fetus can be fresh with partially expanded lungs or severely autolyzed. Mild fibrinous pleuritis and peritonitis may exist noted, every bit well equally bronchopneumonia. Placentitis is mild with hemorrhagic cotyledons and an edematous intercotyledonary area. Campylobacter spp tin be identified past darkfield examination of abomasal contents or civilization of placenta or abomasal contents. Isolation and identification of the species involved is important if vaccination is to be instituted. Venereal campylobacteriosis can be controlled by artificial insemination and vaccination. Campylobacter spp are zoonotic, and C jejuni is an important cause of enteritis in people. (See as well Bovine Genital Campylobacteriosis Bovine Genital Campylobacteriosis .)

Chlamydophila abortus, the cause of enzootic abortion of ewes, causes sporadic abortion in cattle. Most abortions occur near the end of the concluding trimester, simply they tin occur earlier. Placental lesions consist of thickening and yellow-brown exudate adhered to the cotyledons and intercotyledonary areas. Histologically, placentitis is consistently present, and pneumonia and hepatitis can exist found in some cases. C abortus can be identified past examination of stained smears of the placenta or by ELISA, fluorescent antibody staining, PCR, or isolation in embryonated chicken eggs or cell culture. Organisms can often be identified in the lungs and liver merely not as consistently equally in the placenta. There are no vaccines for cattle, although they are produced for sheep Enzootic Abortion of Ewes (EAE) Also come across Direction of Reproduction: Sheep. Abortion in ewes, as in cows, is non e'er easily diagnosed. Although many of the toxins that crusade abortion in cows also cause problems in ewes... read more . The bacterium is zoonotic, occasionally producing life-threatening disease and abortion in pregnant women.

Epizootic bovine abortion is localized to the foothill region surrounding the Sacramento/San Joaquin Valley and the Eastern Sierra Nevada range of California, Oregon, and Nevada. Epizootic bovine abortion usually causes a protracted abortion storm affecting primarily heifers or cows recently introduced to the geographic region; however, abortion can occur 3–5 months after leaving the endemic area. Ballgame is unremarkably in the terminal trimester, and rates may be as high every bit threescore%. The animals abort without illness, and the fetus is seldom autolyzed.

A novel Deltaproteobacterium closely related to Myxococcales,Pajaroellobacter abortibovis, has been identified as the etiologic agent. It is transmitted past the argasid tick Ornithodoros coriaceus ("pajaroello tick"). The aborted fetus may accept hepatomegaly, splenomegaly, and generalized lymphomegaly. Microscopically, there is marked lymphoid hyperplasia in the spleen and lymph nodes and granulomatous inflammation in well-nigh organs. Fetal IgG is increased. Cows seldom abort in subsequent pregnancies, and heifers are often exposed to owned areas before convenance age in an effort to prevent abortions.

Infectious bovine rhinotracheitis (IBR) is a major cause of viral abortion worldwide, with abortion rates of five%–60% in nonvaccinated herds.

The virus is widespread, causes latent infections, and can recrudesce; therefore, any cow with a positive IBR titer is a possible carrier. The virus is carried to the placenta in WBCs; over the adjacent 2 weeks to 4 months, information technology causes a placentitis, then infects the fetus and kills it in 24 hours.

Abortion tin occur any fourth dimension but usually is from four months to term. Autolysis is consistently present. Occasionally, at that place are modest foci of necrosis in the liver, but in a large majority of cases there are no gross lesions in the placenta or fetus. Microscopically, small foci of necrosis with minimal inflammation are consistently present in the liver. Necrotizing vasculitis is mutual in the placenta.

The pathogenic leptospires were formerly classified as serovars of Leptospira interrogans, but they have been reclassified into seven species with >200 recognized serovars. Leptospira serovars Grippotyphosa, Pomona, Canicola, and Icterohaemorrhagiae unremarkably cause abortions in the last trimester, 2–six weeks after maternal infection. The most common organisms in cattle are L borgpetersenii serovar Hardjo type hardjobovis, L interrogans serovar Hardjo type hardjoprajitno, L interrogans serovar Pomona, and Fifty kirschneri serovar Grippotyphosa.

Serovar Hardjo is host adjusted to cattle and tin can establish lifelong infections in the kidneys and reproductive tracts. In addition to third trimester abortions, serovar Hardjo reduces conception rates in carrier cows and cows bred to carrier bulls.

Although dams may show clinical signs of leptospirosis, most abortions are in otherwise healthy cattle. Ballgame rates vary from 5%–40% or more.

The leptospires cause a lengthened placentitis with avascular, light tan cotyledons and edematous, yellowish intercotyledonary areas. The fetus usually dies 1–2 days before expulsion and therefore is autolyzed. Occasionally, calves are born alive only weak. Fetuses infected with serovar Pomona may bear witness icterus. In that location are no specific lesions, just placenta and fetus should be submitted to the laboratory for fluorescent antibody staining or PCR testing for Leptospira.

Although maternal titers are probably waning by the fourth dimension of abortion, an initial titer of >one:800 may exist suspicious. Approximately one-tertiary of cows aborting considering of serovar Hardjo accept titers of <1:100 at the time of abortion. Cows infected with serovar Hardjo tin can shed the organism in urine throughout life. For other serovars, the dam'due south urine can be cultured or examined for leptospires within two weeks of abortion.

For control, sources of infection (such every bit feed or water contaminated by dogs, rats, or wild fauna) should be identified and eliminated. At that place is very piddling or no cross-protection among serovars. Immunization is based on the use of multivalent vaccines. The primary vaccination requires two doses at a 4- to 6-week interval followed by an annual booster. In some areas, use of a bacterin every 6 months provides skillful protection confronting serovars Grippotyphosa, Pomona, Canicola, and Icterohaemorrhagiae but does non protect confronting infection and renal shedding by serovar Hardjo. New monovalent serovar Hardjo vaccines that prevent infection, only exercise not cure existing infections, are bachelor.

The post-obit treatments have been found to eliminate the renal carrier country: a single injection of oxytetracycline (xx mg/kg, IM), a single injection of tilmicosin (x mg/kg, SC), ceftiofur (5 mg/kg/day, IM, for 5 days or xx mg/kg/solar day, IM, for three days), or amoxicillin (xv mg/kg, IM, ii injections 48 hours apart).

Leptospirosis is zoonotic, and urine and milk of dams may be infective for upward to iii months, except for Hardjo, in which case cows tin exist infective for life if not treated. (Meet also Leptospirosis Leptospirosis .)

Listeria monocytogenes can cause placentitis and fetal septicemia. Abortions are usually desultory just may impact 10%–20% of a herd. Ballgame occurs at whatever phase of gestation, and the dam may have fever and anorexia earlier the ballgame; retained placenta is common. The fetus is retained for 2–3 days after death, and so autolysis may be extensive. Fibrinous polyserositis and white necrotic foci in the liver and/or cotyledons are common. Diagnosis is past culture of Listeria from fetus or placenta. There is no available bacterin. Listeriosis Listeriosis is a reportable affliction in many areas and is a serious zoonosis, with spread possible through improperly pasteurized milk.

Fungal placentitis due to Aspergillus sp (septated fungi, 60%–80% of cases), or to Mucor sp, Absidia, Rhizopus sp, and a few other nonseptated fungi, is an important cause of desultory bovine abortion. Abortions occur from 4 months to term and are near common in winter. It is believed the fungi gain entry through the oral or respiratory tracts and travel hematogenously to the placenta. Placentitis is severe and necrotizing. Cotyledons are enlarged and necrotic with turned-in margins. The intercotyledonary surface area is thickened and leathery. Adventitious placentation is common. The fetus seldom is autolyzed, although information technology may be dehydrated; ~30% have grey ringworm-like skin lesions principally involving the head and shoulders. The diagnosis is based on the presence of fungal hyphae associated with necrotizing placentitis, dermatitis, or pneumonia. Fungi tin as well be isolated from the stomach contents, placenta, and skin lesions. Isolation must be correlated with microscopic and gross lesions to exclude contagion afterward abortion.

Neospora caninum is found worldwide and is the most common cause of ballgame in dairy and beef cattle in many parts of the The states.

Dogs and coyotes are definitive hosts for North caninum and can be the source of infection. Ballgame can occur whatsoever time later 3 months of gestation but is nearly common betwixt four and 6 months of gestation. Neospora tin be associated with sporadic abortions or abortion storms, and repeat abortions in cows take been reported.

Almost infections upshot in an asymptomatic congenitally infected calf. Some infected calves are born with paralysis or proprioceptive deficits. Cows are not clinically ill, and placental memory is non common. The fetus is commonly autolyzed or, in a few cases, mummified and rarely has gross lesions.

Microscopically, nonsuppurative inflammation is common in the brain, heart, and skeletal muscles. Organisms tin can be identified in these tissues and the kidneys by ways of immunohistochemical staining and PCR assay. Many tardily gestation fetuses have detectable precolostral antibodies. They remain infected for years and peradventure for life. Vertical transmission is common.

During pregnancy, Neospora Neosporosis organisms can become activated and infect the fetus. This is thought to be the most mutual source of infection. There is no handling. Strict hygiene to preclude fecal contagion of feed by dogs or coyotes may aid in prevention. A commercial vaccine is bachelor.

Tritrichomonas foetus infection causes a venereal disease that commonly results in infertility just occasionally causes abortion in the first half of gestation. Placentitis is relatively mild, with hemorrhagic cotyledons and thickened intercotyledonary areas covered with flocculent exudate. The placenta is oftentimes retained after abortion. A pregnant proportion of cows develop pyometra.

The fetus has no specific lesions, although T foetus can be found in abomasal contents, placental fluids, and uterine discharges. Infected cows typically clear the organism within twenty weeks, but bulls, specially those infected after three years of age, can become lifelong carriers. At that place is no legal, effective treatment for individual animals. Herd treatment is based on identifying and segregating pregnant females from "at-take a chance" females for ≥5 months and by identifying and culling all infected bulls. Prevention is by artificial insemination or natural insemination using noninfected bulls. A killed, whole-jail cell vaccine is available for use in cows to help reduce shedding. (See besides Trichomoniasis Trichomoniasis .)

Trueperella pyogenes causes sporadic abortion at any stage of pregnancy. Rarely, the incidence in a herd may reach epizootic levels. The bacterium is present in the nasopharynx of many salubrious cows and in abscesses. It is not normally present, even every bit a contaminant, in fetuses or fetal membranes, and isolation is almost ever significant. Information technology gains entry to the bloodstream and causes an endometritis and placentitis, which is diffuse with a reddish brown to brown color. The fetus is usually autolyzed, with fibrinous pericarditis, pleuritis, or peritonitis possible.

Bronchopneumonia may exist evident on histopathology, but T pyogenes is best cultured from placenta or abomasal contents. Abortion is unremarkably sporadic, and no effective bacterin is available.

Ureaplasma diversum is a common inhabitant of the vagina and prepuce of cattle that too causes abortions. Abortions are normally sporadic, but astringent outbreaks occur on occasion. The infection may too result in stillbirths and birth of weak calves. Most fetuses are aborted in the third trimester and are well preserved. The cows are non ill, simply retained placentas are mutual. Placentitis and a necrotic amniotic membrane are common features. The intercotyledonary areas are usually thickened and sometimes contain areas of fibrin degradation and hemorrhage. In that location are no gross lesions in the fetus. Microscopically, there is nonsuppurative placentitis and pneumonia characterized by accumulations of lymphocytes effectually bronchi and by diffuse alveolitis. Diagnosis is by isolation of U diversum from the placenta, lungs, and/or abomasal contents.

Akabane virus Akabane and Related Simbu Serogroup Virus Infections in Ruminants Akabane and related Simbu serogroup viruses are transmitted to ruminants by Culicoides midges. They cause congenital abnormalities of the CNS and musculoskeletal system in ruminants.... read more (where present) causes abortion and fetal anomalies. Parainfluenza-3 virus causes abortion in experimentally inoculated seronegative cattle, merely is seldom, if e'er, diagnosed in field cases of abortion. Occasionally, Salmonella spp cause ballgame storms. The cows are normally sick, and the fetuses and placentas are autolyzed and emphysematous. Salmonellae tin can be isolated from the abomasal contents and fetal tissues and from uterine fluids and the dams' feces. Mycoplasma spp, Histophilus somni, and a wide variety of other bacteria can also cause sporadic abortions in cattle. Schmallenberg virus, discovered in Europe in 2011, belongs to the Simbu serogroup and has been associated with infertility, ballgame, and fetal malformation in several ruminant species.

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Source: https://www.merckvetmanual.com/reproductive-system/abortion-in-large-animals/abortion-in-cattle

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