GI3- Farm Diarrhea

immunosuppressive

immune cells; viral receptors on lymphocytes and monocytes.

shed in oral, nasal secretions, feces, urine, semen, biting insects, trans-placentally, iatrogenically

if you vaccinate the calf with a MLV, the dam and fetus can be infected--> abortion, cerebellar hypoplasia, PI calf

acute BVD, persistent infection, mucosal disease (when PI is vaccinated with MLV), reproductive problems, thrombocytopenia/ bleeders, immunosuppression, respiratory disease

when infected in-utero at around 120 days gestation b/c their immune system doesn't recognize it as foreign and it becomes self-antigen; must be infected with a non-cytopathic strain

fever, depression, diarrhea, oral/ esophageal/ abomasal ulcers, +/- lameness with coronary ulcerations; clinical course 7-10 days

less than 2 years old

when a PI calf (infected with ncp strain) is exposed to a cytopathic strain or their ncp strain mutates to a cp strain

[amplified from acute BVD] severe explosive diarrhea, GI ulceration from muzzle to colon, necrosis of peyer's patches, high fever, mortality 100%

more susceptible to respiratory and GI infections and are treated for recurring disease; if exposed to cp strain or gets vaccinated, mucosal disease and death

• <100 days--> abortion
• 100-120 days--> PI calf
• >120 days--> cerebellar hypoplasia, arthrogryopsis, etc

• abortion and poor conception
• infection during middle trimester--> cerebellar hypoplasia, micro-ophthalamia, cataracts, retinopathy with pigmentation

infection with Type II BVD

spontaneous hemorrhages along the GI tract, sclera, at injection sites, death of adults and young, platelet counts <10k

erosions of palate, gums, and under tongue, linear esophageal erosions, abomasal/ ruminal ulcers, peyer's patch necrosis, +/- secondary pneumonia

• virus isolation from blood, feces, areas of erosion
• serology- virus neutralization with 1 samples 10-14 days apart
• PCR on blood, fluids, tissue
• antigen capture ELISA of blood or tissue
• immunohistochemistry of collected tissue

• Pros: safe to use at any stage of pregnancy
• Cons: must be administered twice initially and boostered all the damn time, mainly stimulates only humoral immunity

• Pros: superior immunity (cell mediated and humoral immunity), single injection
• Cons: may cause abortion if used in early to mid gestation

• Mycobacterium avium ss. paratuberculosis
• acid-fast, gram + bacteria

domestic ruminants and wild/ exotic hoofstock; if your cows are co-mingling with wild deer etc, they may become infected that way (even in a closed, negative herd)

bacteria in the feces of adults contaminates the environment for the calf, or infective colostrum is administered to calf--> ingested organisms are absorbed and distribute to the intestinal lymph nodes--> slowly multiply in the LN and work back to intestinal mucosa at the ileo-cecal junction--> colonize ileo-cecal LN and travels to SI--> granulomatous reaction in intestinal wall--> poor water absorption, PLE

Macrophages (can resist lysosome within macs/ lymphs)

6-8 months old, but most within first 30 days

granulomatous reaction; poor absorption of water, loss of proteins (albumin) into gut lumen.

large intestine; small intestine

eliminate all offspring of infected dams to minimize maintenance of the disease within the herd

normal appetite, chronic wasting, chronic diarrhea, hypoproteinemia, submandibular edema (bottle jaw)

>2 years old

• fecal culture with specialized media- mycobactin J for growth, brother cultures are faster
• serologic tests- AGID, ELISA
• DNA probe of feces
• Histopathology- biospy or necropsy (acid fast organisms)

• strict sanitation, remove calves at birth/ do not let nurse dam, clean udder before nursing (beef)
• herd testing with fecal culture and serologic testing
• don't spread manure on fields (bacteria live in manure >1yr)
• don't buy animals from unknown sources, embryo recipients
• consider vaccination in high prevalence herds (need state vet approval, must be tested for bovine TB first)
• monensin to keep cows (shedding decreases but doesn't go away)

• fecal culture + is definitive + (but takes forever), used to establish herd status
• once a herd is established positive, blood ELISAs are more specific

• need approval of state vet
• must test negative for bovine TB first
• only done in positive herds
• done in calves <30 days of age
• predisposes to a granuloma/ abscess in brisket

• coronavirus ( same as for calf scours)
• immunity to natural infection is short-lived
• causes outbreaks!
• incubation 3-5 days

• explosive outbreak of diarrhea +/- hemorrhage
• normal TPR
• normal appetite
• falling milk production
• severity greater in older cows

3-5 days

fecal-oral +/- MAYBE aerosol transmission

• EM of feces in acute cases to ID coronavirus
• ELISA and PCR
• clinical signs
• r/o Salmonellosis

supportive- hydration

grazing- L3 on forages

winter/ environment not hospitable for parasite--> L4 encyst in abomasal wall--> late winter/ spring--> rapid excystation of parasites--> diarrhea/ disease

• large volume, watery diarrhea
• bottle jaw- hypoproteinemia/ hypoalbuminemia- intermandibular edema
• normal TPR

• late winter (Feb-April)
• 2-4 year old animals

• Johne's animals are usually older
• Ostertagia occurs the first time these animals are out on pasture

• history and clinical signs
• increased abomasal pH
• plasma pepsinogen >3,000 due to increased pH inhibiting transformation of pepsinogen to pepsin
• McMaster's fecal initially negative b/c larvae are still emerging, plus you can't ID strongyle type eggs... they all look the same (parasitologists larvate eggs and ID adult parasite...we can't do this)

• Ivermectin, Doramectin, Moxidectin (avermectins macrocyclic lactones)
• Albendazole or Fenbedazole (benzamidazoles)

moroccan leather to abomasal folds

ovine herpesvirus 2; aerosols/ direct contact with young lambs (less than 1 yr of age)

diarrhea, catarrhal nasal exudate, ocular d/c, corneal edema, generalized lymphadenopathy, pneumonia

low; high

• clinical signs
• histopathology- lymphoid panerteritis, GI ulcerations
• PCR sent to colorado state

BVD, IBR, bluetongue, Rinderpest, foot and mouth

you can't and they all die

• S. dublin (host-adapted)
• S. newport (emerging)
• S. typhimurium (zoonotic)

diarrhea (maybe watery, maybe bloody), inappetence, down on milk, abortions, +/- fever

CBC: initially panpeukopenia an neutropenia; then becomes leukocytosis

• feco-oral, direct contact
• stresses cattle can be asymptomatic shedders
• maybe horn flies as potential fomites

copper deficiency, feeding indiscretions, hert failure, renal disease