1. Calf Scours Causes, Prevention, & Treatment Brendan Kraus, DVM Thanks Dr. Larson

2. Calf Scours Complex Multifactorial Disease Host Agent Environment

3. Host Factors Level of Immunity Passive Transfer Calves are born without antibodies Calves should ingest at least 1 gallon of colostrum in the first 12 hours of life (recommendations have changed) Many calves ingest inadequate levels

4. Host: Level of Immunity Passive Transfer

5. Host: Level of Immunity Prevention Tips 1) Ensure Adequate Passive Transfer 2) Prevent Dystocia 3) Bull Selection Based on EPD for birth weight and calving ease

6. Select for Calving Ease

7. Host: Level of Immunity Prevention Tips 4) Proper Development of Dam Dam should calve at BCS 5.5-6.0 Avoid over-condition or rapid weight gain in late gestation (fat in pelvic canal)

8. BCS 6

9. Environment Factors Overcrowding Poor Sanitation Damp or wet ground Age of Dam Poor Quality Milk/milk replacers

10. Environment: Overcrowding/Sanitation Prevention Tips 1) Optimize Environment/Sanitation Calving areas should be as clean and dry as possible Calves should be dispersed as much as possible (intensive vs. extensive)

11. Intensive vs. Extensive Concentration Intensive Permits Ready Intervention Extensive Favors Hygiene

12. Environment: Overcrowding/Sanitation Prevention Tips 1) Optimize Environment/Sanitation (cont.) Separate calving pasture from winter feeding pastures (more uncommon for spring calvers) Feeding strategy considerations

13. Feeding Strategy Considerations Bale feeders Spread bales Feed bunk movement Water sources Stockpiled forage

14. Environment: Overcrowding/Sanitation Prevention Tips 1) Optimize Environment/Sanitation (cont.) Calving areas should have adequate drainage Provide protection from the wind

15. 2) Control Exposure Which calves are at risk? Environment: Overcrowding/Sanitation Prevention Tips

16. Calves are not Equally at Risk! Most calves are 1 to 2 weeks of age at time of death Calves older than 3 weeks are at low risk of death From David Smith et al, 2004 1 to 3 week-old calves are also shedding the most scours pathogens

17. Calves are not Equally at Risk! Calves born early in the calving season are at low risk Calves born late in the calving season are at high risk From David Smith et al, 2004

18. Calves are not Equally at Risk! From David Smith et al, 2004 The risk of scours and the severity of disease in each affected calf increases as the calving season progresses The age at disease onset decreases as the calving season progresses

19. 2) Control Exposure (cont.) Pasture Rotation Keep young calves away from older calves Environment: Overcrowding/Sanitation Prevention Tips

20. Control Exposure: Keep Young Calves away from Older Calves

21. Pasture Rotation 1) Mid-late gestation pasture (minimum) Can be sorted at preg check OR 2) Move heavies every 1-3 weeks New calves being born on clean pasture Older calves staying behind in contamination Herd reassembled for breeding Youngest calf around 3 weeks old

22. Environment: Overcrowding/Sanitation Prevention Tips 2) Control Exposure (cont.) Calve Heifers Early Be Wary of Outside Calves

23. Agent Escherichia coli (1-6 days) Clostridium perfringens (1-14 days) Rota Virus (5-21 days) Corona Virus (5-36 days) Cryptosporidium (6-21 days) Salmonella (6-36 days)

24. E. Coli 2 types: Septicemia & Enterotoxogenic Usually within 3-5 days of life Severe, watery diarrhea (secretory, ETEC) Depression Hypothermia Distant Infections (joints, brain navel, septicemia)

25. Enterotoxogenic E-coli

26. Clostridium perfringens < 2 weeks old Low morbidity : High mortality Healthy, fast growing calves Heavy milking dams Sudden Death Diarrhea/Abdominal Pain Necrosis of small intestine Enlargement of intestinal lymph nodes

27. Rotavirus Most Common Often found in mixed infections 5 days to 3 weeks of age Affects small intestine Voluminous (Malabsorptive) Lactose washout with osmotic diarrhea Dehydration At least 7 days to repair intestinal damage

28. Coronavirus More Severe than Rota 5 days to 30 days of age Large and small intestine Dehydration Anorexia Infects intestinal cells more severely Malabsorption/maldigestion Respiratory Infections

29. Cryptosporidium Zoonotic Potential 7 days to 30 days of age Protracted, non-responsive diarrhea Intracellular but extracytoplasmic Drugs difficult to kill Off Label

30. Salmonella > 10 days of age Foul smelling diarrhea Fibrin and mucosa may be present in stool Distant infections

31. Treatment Challenges Hypothermia Hypoglycemia Acidosis Low Protein Electrolyte Imbalances Hypovolemia/Dehydration

32. Treatment Cornerstone of Treatment is Fluid Therapy Calculate Dehydration % and Replacement Amount

33. Fluid Therapy

34. Correct Dehydration Correct Electrolyte Imbalances Combat Shock Support Internal Organ Function Supplement Energy

35. Fluid Therapy Routes of Administration Oral Intravenous

36. Oral Fluids Must have GI motility (body temp) Must have GI perfusion (dehydration) Must have absorptive function (damage) Benefits-Inexpensive

37. Intravenous Fluids Rapid Replacement of fluid deficits Replacement of Electrolytes (bicarbonate) Base Deficit Correction Replacement of Ongoing Losses

38. Treatment, Other Nutritional Support Body Temperature Maintenance Maintain Oral Fluids/Electrolytes Antibiotics +/-

39. Scours Outbreak Short Term Intervention Strategies Treat affected calves Calving site selection and management Change location of calves Calving season Move pregnant cows away from nursing cows Dystocia management Monitor calving closely Good husbandry and nutrition of dam

40. Scours Outbreak Long Term Prevention Strategies Care and Nutrition of Dam Dystocia Sire selection and heifer development Calving site selection and management Plan ahead, get site ready Pasture Rotation Be as aggressive as you need for your operation Vaccination (last for a reason)

41. Scours Vaccination Dam vaccinated/antibodies in colostrum To be used as a tool in the arsenal Usage determined by risk Vaccination of younger stock Must have two rounds prior to calving the first year Vaccinations available for the calf Will not work as sole prevention measure

42. A Too Common Scenario? It’s March 3, a cold drizzle is coming down as you slide across the pasture in 4WD. Vet and client are surveying a pasture of 40 cow/calf pairs. Calves range in age from 1 day to 2 months. The mud is ankle deep. Approximately 50% of the calves have fluid stools. Four calves have died in the last 2 days, and at present, 4 calves are weak and unable to stand. The client turns and asks, “What do you think we should we do?”

43. Questions?