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

2. Calf Scours Complex • Multifactorial Disease Host Environment Agent

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 ImmunityPassive Transfer

5. Host: Level of ImmunityPrevention Tips • Ensure Adequate Passive Transfer • Prevent Dystocia • Bull Selection Based on EPD for birth weight and calving ease

6. Select for Calving Ease

7. Host: Level of ImmunityPrevention 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/SanitationPrevention Tips • 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/SanitationPrevention 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/SanitationPrevention Tips • Optimize Environment/Sanitation (cont.) • Calving areas should have adequate drainage • Provide protection from the wind

15. Environment: Overcrowding/SanitationPrevention Tips • Control Exposure • Which calves are at risk?

16. Calves are not Equally at Risk! 1 to 3 week-old calves are also shedding the most scours pathogens • 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

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! • 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 From David Smith et al, 2004

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

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/SanitationPrevention 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. Fluid Therapy • 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?