Cow and Calf Diarrheal Disease

Question 1

What are 3 infectious causes of diarrhea in adult cattle?

Answer 1

-Salmonella
-BVDV
-Mycobacterium avium subsp. paratuberculosis (Johne’s disease)

Question 2

What serovar of Salmonella enterica is host adapted to cattle? What does this mean for infected animals?

Answer 2

Salmonella enterica Dublin. Infected animals can have lifelong infection (never cleared) with intermittent shedding. Typhoid Mary cow!

Question 3

What are the 2 classic presentations of severe salmonellosis in adult cattle?

Answer 3

-Peracute hemorrhagic enterocolitis in cattle of any age
-Late term abortion

Question 4

Historically what was the most important source of Salmonella infections? Today what is the most important source?

Answer 4

Historically: Contaminated animal by-product protein feeds
Today: Cow-to-cow transmission. Salmonellosis is endemic on many large dairies.

Question 5

If you see hemorrhagic diarrhea across all age groups of cattle, what pathogens are you most suspicious of?

Answer 5

Salmonella or BVDV

Question 6

What clinical signs are associated with enteric salmonellosis?

Answer 6

Classical peracute/acute enteric Salmonellosis ->severe hemorrhagic
enterocolitis, sudden onset bloody diarrhea with fever, depression, complete anorexia, rapid dehydration and possibly death.
However, the entire spectrum of enteritis may be seen, ranging from profuse loose, nonhemorrhagic stool through to almost inapparent disease.

Question 7

What factors can impact the severity of disease in a cow exposed to salmonella? Which is the most important factor?

Answer 7

Immune status of the cow, the pathogenicity of the serotype and the infecting dose. Immune status of the cow is most important.

Question 8

What diagnostic tests can be used to identify salmonellosis? Pros and cons?

Answer 8

Culture: Definitive proof requires isolation/identification of the organism from feces in the live animal or intestinal contents obtained at post mortem. Hard to grow Salmonella because rapidly overgrown by other enterics. Often need serial samples and collection method is finicky.
PCR: Better, offered by some labs
Serology: can identify carriers.

Question 9

What constitutes diagnosis of salmonella Dublin carrier status in cattle?

Answer 9

3 positive ELISA tests over 9-12 month period

Question 10

What is the treatment for salmonellosis in cattle?

Answer 10

1- Supportive fluid therapy – oral or intravenous fluids depending upon economics and severity of the fluid losses. In practice – hypertonic saline can be a very
valuable resuscitation fluid in the severely dehydrated animal, followed by oral fluids.
2- Antimicrobials are controversial and should only be considered in cases of bacteremia, which is more likely in calves.

Question 11

How can salmonellosis be prevented in a herd?

Answer 11

Sanitation, isolation of diarrheic animals and identification of a point source if one exists.
Maintain a closed herd if possible –increasingly rare.
Currently available vaccines are not efficacious.

Question 12

What is the general pathophysiology of Persistent BVDV infection and mucosal disease?

Answer 12

Animals infected in utero with non-pathogenic strain ->No immunity at all -> within 1st year get pathogenic strain -> mucosal disease -> 100% fatal

Question 13

What clinical syndromes is BVDV infection associated with?

Answer 13

1- Reproductive failure – abortion at any stage
2- Congenital abnormalities.
3- Enteritis – that can vary from mild to severe, hemorrhagic and lifethreatening.
3- Hemorrhagic syndrome (thrombocytopenia)
4- Persistent infection and mucosal disease

Question 14

What are signs of severe clinical disease associated with BVDV infection?

Answer 14

High fever (104F+)
Acute bloody diarrhea
Marked tachypnea
Erosions on hard and soft palate, tongue and gingiva

Question 15

What are signs of moderate clinical disease associated with BVDV in healthy, well vaccinated cattle?

Answer 15

Moderate fever
Mild diarrhea
Self-limiting

Question 16

Why are serological tests not useful in detecting BVDV positive cattle?

Answer 16

Vaccination makes results uninterpretable

Question 17

How is BVDV treated?

Answer 17

Mild cases: Supportive – fresh water, palatable forages and no exogenous stressors
Severe cases: Fluid therapy (oral or i.v) Broad spectrum antibiotics due to the suppression of cellular and humoral immune function caused by BVDV.

Question 18

What are the 2 cornerstones of BVDV prevention and control?

Answer 18

Identify and cull persistently infected animals and VACCINES

Question 19

How can you identify animals that are persistently infected with BVDV on a herd level?

Answer 19

Skin/ear notch test all animals at birth.

Question 20

What is the most common cause of chronic diarrhea in adult cattle?

Answer 20

Johne’s disease (Mycobacterium avium subsp. paratuberculosis)

Question 21

Why don’t dairy cows develop fulminate Johne’s disease?

Answer 21

They don’t live long enough

Question 22

What impact does Johne’s disease have on a dairy herd?

Answer 22

Economic impact of subclinical infection on milk production and reproductive efficiency

Question 23

How are cattle infected with Johne’s disease?

Answer 23

Infection is usually acquired in the immediate neonatal period (maternity area, dam, etc.), with a subsequent incubation period of 2-10 years.

Question 24

What are the prominent clinical sign of Johne’s disease in cattle?

Answer 24

1- Chronic diarrhea – no blood, no fever
2- Weight loss
3- Production losses esp as progresses
4- Ventral edema due to hypoalbuminemia in advanced cases

Question 25

How is Johne's disease treated?

Answer 25

It is not treated except in very rare cases

Question 26

How can Johne's disease be prevented?

Answer 26

Limit potential exposure of new born calves to adult cow feces. Use colostrum from tested, Johne’s negative cattle. No vaccine.

Question 27

What are signs of Winter Dysentery and when is it usually seen?

Answer 27

1-2 week outbreaks of watery diarrhea usually affecting first lactation heifers more severely. Seen November through February.

Question 28

What causes Jejunal hemorrhage Syndrome?

Answer 28

Aetiology is uncertain- complex disease. Overgrowth of Clostridium perfringens type A within the small intestine and maybe Aspergillus fumigatus.

Question 29

What is pathophysiology of Jejunal hemorrhage syndrome?

Answer 29

Blood clots cause small bowel obstruction and lead to colic, abdominal distension, +/- palpable loops of small bowel on rectal exam, and small volume bloody/melenic diarrhea.

Question 30

What is the best treatment for jejunal hemorrhage syndrome? What is prognosis?

Answer 30

Surgical- Right flank laparotomy – manual massage of jejunal contents –approximately 60% prognosis. If obstructing clots cannot be relieved/reform quickly, or substantial fibrinonecrotic bowel is present – grave prognosis.

Question 31

How do feces associated with abomasal ulcer differ from those associated with jejunal hemorrhagic syndrome?

Answer 31

Classic ulcer: "engine oil" melena JHS: Looks like abomasal ulcer, but with fresh blood too. "Strawberry jam"

Question 32

What are risk factors associated with neonatal calf diarrhea?

Answer 32

Poor dry cow program (dams shedding more pathogens at time of birth into calving area) Contaminated colostrum Failure of passive transfer Poor nutrition Lack of water & comfort Dirty environment Exposure to adults Group housing Stressful management (Dehorning, Castration, Vaccination) Change in Feed, Housing, Weather, Commingling Inappropriate Vx/Tx

Question 33

What sorts of things are considered stressors of calves?

Answer 33

- Dehorning, Castration, Vaccination - Comingling - Changes in Feed, Housing, Weather

Question 34

Why is it considered good practice to separate calves from the dam within 10 - 15 minutes of birth?

Answer 34

Removing calves from the maternity area within 10‐ 15 minutes of birth limits the number of unsuccessful attempts to stand and face‐first falls into bedding that is contaminated with manure and respiratory secretions from the adult animals. Early separation also prevents the calf from suckling dirty udders and consuming insufficient amounts of colostrum which contributes to failure of passive transfer.

Question 35

What behaviors are normal for a calf after birth and when are they expected to happen?

Answer 35

Sternal within 5 minutes Attempting to stand by 10 minutes Many face-first falls "manure meals" Standing by 1 hour

Question 36

Where does exposure to neonatal calf diarrheal pathogens occur?

Answer 36

1- Calving pack – dirty bedding, dirty cows 2- Colostrum – not collected, cooled, or stored properly 3- Tube Feeders – not cleaned and disinfected between calves 4- Feeding equipment – clean and disinfect 5- Warming box – need to clean/disinfect between calves; avoid porous surfaces 6- Calf housing & bedding – clean/disinfect between calves; use adequate bedding; avoid porous surfaces 7- Contaminated people – limit traffic between adult herd and neonatal calves

Question 37

What are the 3 most common pathogens associated with neonatal calf diarrhea?

Answer 37

Rotavirus, Coronavirus, Cryptosporidium

Question 38

What are peak ages for shedding of common neonatal calf diarrhea pathogens?

Answer 38

ETEC: 1 - 3 days Rota, Corona, Crypto: 5 - 10 days Salmonella, C. perfringens: any Giardia, Coccidia: > 21 days

Question 39

What is the most common pathogen diagnosed in 1 - 3 week old calves with abnormal manure?

Answer 39

Cryptosporidium parvum

Question 40

What is the infective stage of cryptosporidium?

Answer 40

Oocyst

Question 41

How long does it take to start shedding Crypto? How long is the shedding period?

Answer 41

On average, after ingestion of the oocysts, it takes at least 3 days for this cycle to complete before shedding is noted. Shedding last approximately 10 days.

Question 42

How common is Crypto on dairy farms?

Answer 42

Nearly ubiquitous- found in 60‐90% of North American dairy herds.

Question 43

How does Cryptosporidium cause pathology?

Answer 43

Once ingested, oocysts undergo the process of excystation in which sporozoites are released into the intestinal lumen and invade the brush border of the intestinal epithelial cells. After invasion, villous fusion, atrophy and crypt inflammation results in the malabsorptive and inflammatory diarrhea seen clinically.

Question 44

What type of cells does Crypto infect and where in the cell is it found? What effect does this have on treatment of infection?

Answer 44

One of the reasons that crypto is so difficult to treat is because it lives within a very specific location within the enterocyte: intracellular, yet extracytoplasmic.

Question 45

How does rotavirus cause pathology?

Answer 45

Infects enterocytes and causes villus atrophy & malabsorption

Question 46

How do you test for rotavirus and when is the best time to test?

Answer 46

PCR EARLY in course of disease

Question 47

What cells does coronavirus infect and how does it cause pathology?

Answer 47

Infects enterocytes AND COLONOCYTES – Villous blunting = malabsorption – Blood if colon involved

Question 48

What diarrheal pathogen can cause sloughing of intestinal casts?

Answer 48

Salmonella

Question 49

What type of disease does infection with Clostridium perfringens type A and C cause?

Answer 49

Necrotic enteritis, hemorrhagic abomasitis Exotoxins damage intestinal & abomasal mucosa – Severe enterotoxemia, rapid death without treatment – Inflammation, necrosis → malabsorptive diarrhea

Question 50

How does enterotoxic E coli (ETEC) cause pathology?

Answer 50

– Adheres to enterocytes through fimbriae – Little to no inflammation (no blood in manure) – Secretory diarrhea due to enterotoxins

Question 51

Which calf diarrhea pathogens pose a threat to humans?

Answer 51

C. parvum, Salmonella spp., Giardia

Question 52

What is the protocol for routine, herd level testing for neonatal calf diarrhea pathogens? What levels of positive detections are considered problematic?

Answer 52

Collect fresh feces from 6 untreated calves that represent the age group affected on the farm. Change gloves between samples and do not pool samples. Use PCR to assess how many of the 6 samples are positive for each of the organism. 1. For rota, corona, crypto: > 2 positive tests out of 6 suggests a problem with that pathogen 2. For Salmonella: zero tolerance policy, any positives for typhimurium, newport, Dublin is problematic

Question 53

When does peak shedding generally occur? How many calves will you test? What test will you request? 1. ETEC 2. Cryptosporidium parvum 3. Rotavirus 4. Coronavirus 5. Salmonella 6. Coccidia

Answer 53

1. ETEC: first 3 days of age 2. Cryptosporidium parvum: 5 – 10 days of age 3. Rotavirus: 5 – 10 days of age 4. Coronavirus: 5 – 10 days of age 5. Salmonella: anytime 6. Coccidia: after 21 days of age Submit individual fecal samples from 6 calves (Don’t Pool). Request PCR tests appropriate for age of animals affected

Question 54

Why is it essential for neonatal calves to receive adequate colostrum?

Answer 54

Calves are born agammaglobulinemic due to type of placentation and require consumption of high‐quality colostrum soon after birth to provide immunity.

Question 55

How long does colostral IgG last?

Answer 55

~ 3 weeks

Question 56

What are the components of colostrum?

Answer 56

* Nutrients- High Fat and Protein content + Vitamins & Minerals * Antibodies * Non‐specific antimicrobials * Maternal leukocytes * Growth factors/Cytokines * Trypsin inhibitor- Protects IgG from proteolytic degradation in the calf GIT

Question 57

What type of immunoglobulin is most abundant in colostrum?

Answer 57

* ~88% IgG * 5% IgA * 7% IgM

Question 58

What component of colostrum helps keep maternal IgG levels high in the calf?

Answer 58

Trypsin inhibitor

Question 59

How does the composition change from colostrum to milk?

Answer 59

-Total solids, fat, protein, IGF‐1, insulin all significantly decrease -Concentration of lactose significantly increases

Question 60

What are diagnostics used to determine IgG levels at the individual and herd level?

Answer 60

Individual calf IgG1 can be measured by radial immune diffusion assay (RID), gold standard, or through turbidometric immunoassays (TIA). Indirect estimation of IgG1 is appropriate for herd level information (does the “herd” have a problem with passive transfer). Serum TP is most common test used to estimate IgG1, but %Brix is equally acceptable.

Question 61

What IgG cut point is used to differentiate calves with adequate and inadequate passive transfer with regards to mortality?

Answer 61

1,000 mg/dl

Question 62

What was the old "mantra" for colostrum feeding? What is the new "mantra"?

Answer 62

OLD: 4 liters in 4 hrs NEW: 4 liters in 1-2 hrs + 2 liters at 12 hrs

Question 63

By what means should colostrum be fed to neonatal calves?

Answer 63

Recommend tube feeding the first 4L (1 Gallon; 4 qts) of maternal colostrum within 1 – 2 hours of birth, and offer a second feeding of 2L (0.5 Gallon; 2 qts) by nipple bottle 12 hours after birth. DO NOT FORCE FEED THIS SECOND FEEDING.

Question 64

Why should colostrum be collected ASAP after parturition?

Answer 64

Deposition of IgG into milk/colostrum stops immediately after the calving process is initiated. As the cow lets her milk down after calving, IgG becomes progressively diluted.

Question 65

What are 4 components of proper colostrum management?

Answer 65

1- Collect ASAP 2- Clean equipment 3- Proper storage- Refrigerate/freeze in small volumes (1 gallon) 4- Do not pool colostrum

Question 66

How can you assess passive transfer in an herd?

Answer 66

Monitor herd’s ability to deliver maternal colostrum by collecting blood from 12 calves 24 hours after birth to 7d of age and measure TP or Brix.

Question 67

What are the new goals for herd level passive transfer?

Answer 67

New guidelines (2020): > 40% > 6.1 g/dL > 70% > 5.7 g/dL

Question 68

What problems are associated with low IgG levels in calves?

Answer 68

Mortality, overall morbidity, diarrhea, respiratory disease

Question 69

1. At what age should blood be collected for Passive transfer assessment? 2. How many calves should be tested? 3. What goal % > 5.7 g/dL? 4. What goal % > 6.1 g/dL?

Answer 69

1. 24 hr to 1 week 2. 12 calves should be tested 3. > 70% > 5.7 g/dL TP 4. > 40% > 6.1 g/dL TP

Question 70

List 3 potential risk factors for failure of passive transfer

Answer 70

* Low volume * Late timing of administration to calf * Delayed collection after calving * High bacterial counts in colostrum from dirty cows or dirty collection or feeding equipment * Pooling colostrum

Question 71

What is the new recommendation for calf feeding?

Answer 71

2 – 3 gallons whole milk per day

Question 72

What effect does providing calves with a higher plane of nutrition have?

Answer 72

* Minimizes the effect of C. parvum on the neonatal calf * Minimize early life weight loss

Question 73

What volume of milk or milk replacer should an average sized Holstein calf drink per day?

Answer 73

2 to 2.5 gallons

Question 74

How does a higher plane of nutrition impact calves infected with C. parvum?

Answer 74

Better Average daily growth and feed efficiency

Question 75

What are the 3 measures of disease for neonatal calf diarrhea?

Answer 75

with abnormal manure, # treated, # detected

Question 76

How do you calculate the calf diarrhea farm detection rate? What is the goal for this metric?

Answer 76

Detection rate = # calves on treatment/ # calves Fecal Score >=2 * Visual detection of abnormal manure using fecal scores (DVM) * Compare to farm treatment records (producer) * GOAL ≥ 85%

Question 77

Describe the UW Calf Health Scoring Criteria for fecal assessment. Which scores are normal vs abnormal and when is treatment indicated?

Answer 77

0- normal 1- semi-formed, pasty 2- loose but remains on top of bedding 3- watery, sifts through bedding 0 - 1 normal manure- no Tx indicated 2 -3 abnormal manure- treatment indicated

Question 78

What differentiates mild from severe cases of neonatal diarrhea?

Answer 78

Mild cases * FS = 2 – 3 * BAR or QAR * Standing * Good suckle and appetite * Fecal blood minimal to none Severe cases * FS = 1 – 3 * Depressed, slow to stand, recumbent, non‐responsive * Suckle minimal to none * T>103 or < 100 °F) * Frank blood in feces * Dehydration

Question 79

When is it OK to use oral electrolyte solution (OES) in claves with diarrhea?

Answer 79

Must have healthy GI tract for OES ie suckle and/or chewing activity. DO NOT USE if abdomen is distended.

Question 80

What are the components of a high-quality OES and what are their functions?

Answer 80

High quality OES contain: 1. Sodium – needed to restore fluid deficits 2. Glucose, citrate, acetate, propionate, OR glycine – to facilitate Na+ absorption 3. Alkalinizing agent –to treat acidosis - 50 – 80 mmol/L - Acetate, propionate, bicarbonate 4. Supplemental energy – treat negative energy balance

Question 81

When should you avoid use of an OES?

Answer 81

Dehydrated, lack of suckle, ventral abdominal distention

Question 82

How do you calculate hydration deficit? How are hydration deficits corrected? What kinds of fluids are used in calves with diarrhea?

Answer 82

* % Dehydration x Body Weight (kg) = L of fluid necessary * Correct half of hydration deficit (2 ‐ 3 L IV) over 4 – 6 hours then reassess clinical condition * Use isotonic IV fluids for rehydration * Should contain bicarbonate and dextrose to address acidosis and hypoglycemia

Question 83

What is a protocol for rapid resuscitation of a down and out calf?

Answer 83

Give 3 x 60 cc syringes of 7.2 % hypertonic saline plus one syringe 10 mL of 50% dextrose administered over 4 minutes (1 minute per syringe, give dextrose first). MUST follow immediately with 2L of warm water via esophageal feeder or bottle if calf will suck.