Practical Biosecurity and Biocontainment on the Ranch

Transcription

1 Practical Biosecurity and Biocontainment on the Ranch Ranch Practicum 2017 Dale Grotelueschen, DVM, MS Great Plains Veterinary Educational Center Clay Center, NE

2 Preventive Health Strategies Proactive thinking about animal health Priorities, Goals, Decisions Systems approaches Risk: Assessment, Management, Tolerance Animal stewardship Herd approaches Role for individual animal care

3 Risk considerations for designing plans to control targeted diseases in individual cattle operations Risk Assessment Are animals exposed or infected now or how likely are they to become exposed in the future? Do these risks need to be addressed? Risk Tolerance/Risk Aversion What is my tolerance to health risks? How much risk am I willing to take?

4 Begin With the End in Mind st 21 d Calving Distribution 2nd 21 d 3rd 21 d % calf crop number calves weaned divided by number cows exposed Pounds weaned per exposed cow Price/pound Cost of production

5 Calving Distribution 70% 21% 6% 10% 30% 40% 10%

6 Epidemic (disease) curve % of Total Head Control WeanVAC OHP OHP = other health protocols Day After Feed Yard Arrival Seeger, et al, Bov Pract 2008;42:1, 27-39

7 Impact of Preconditioning on Feedlot Performance Cattle in preconditioning programs were at 4X less likely need treatment Morbidity Morbidity rates of beef steer calves at two health assessment intervals and for the entire feeding period.

8 Reduced risk for disease, control or elimination of disease Biosecurity the outcome of all actions used to prevent disease agent entry into a unit of interest. Biocontainment the outcome of all actions resulting in control of a disease agent in a unit of interest Dargatz, et al Vet Cl FoodAn 18 (2002) 1-5. Smith, Vet Cl Food An 18:1(2002)

9 Prevent Transmission Eliminate Agent Biosecurity Biocontainment Increase Immunity Dargatz, et al, Vet Clin Food An 18 (2002) 1-5 Smith, Vet Clin Food An 18 (2002)

10 Dargatz, et al, Vet Clin Food An 18 (2002) 1-5 Thomson, JU, Proceedings Am Assoc Bov Pract , 1997 Disease control could be improved by better addressing epidemiologic triad Host Agent Immunity has received most attention in outbreaks and prevention plans Factors addressing exposure tend to be ignored Limited success of health programs Environment

11 Immunity Exposure Disease

12 Exposure Immunity Disease

13 Population Dynamics Effect of Vaccination or Field Exposure Number of Animals Susceptible to Disease Disease Challenge Level Resistant to Disease Relative Level of Disease Resistance

14 Consider commingling as a risk factor whenever combining animals/animal groups in your system Cattle on the ranch Cattle coming onto the ranch or feedlot

15 Health Risks Associated with Introduction of New Cattle into Herds

16 These bulls are genetically superior and possess excellent quality characteristics. Is there a downside to purchasing one or more of these bulls?

17 Other cattle in herd (including calves) are carriers This cow has Johne s disease Chronic diarrhea Contagious Leads to Death Possible link to Crohn s disease in humans

18 Is there a downside to purchasing one or more of these bulls IF THEY ORIGINATED FROM THE SAME HERD AS THE COW?

19 Is there a downside to purchasing this heifer or 100 like her? #624 BVD PI Non-Symptomatic Heifer

20 Offspring of a purchased replacement heifer This is a PI BVD Calf BUT...

21 This Ranch Calved these replacement heifers separate from the resident herd. Tested calves and then dams of positive calves. Positives were culled before commingling with resident herd. Resident herd (as part of existing health program) and new arrivals were vaccinated.

22 This Ranch Bottom line..bvd was not introduced into the herd even though PI animals resulted from the purchase. Spent about $150 on tests that potentially saved thousands over the next years.

23 Persistent Infection - Routes Acute infectionpregnant female exposed to NCP BVDV 93% 1½-4+ months gestation Persistently Infected calf Persistently infected female giving birth 7% (Wittum, et al, Prev Vet Med 49 (2001) 83-94)

24 Reproductive effect of acute BVD around time of insemination Conception Rate 20 d after insemination Pregnancy Rate 77 d after insemination Calving Rate 275 d after insemination Controls that did not become infected during pregnancy 79% (11 of 14) a 79% (11 of 14) c 71% (10 of 14)* Group 1 infected by contact with PI cow and calf 4 days after insemination 60% (9 of 15) b 33% (5 of 15) c 33% (5 of 15) Group 2 infected intranasally 9 days before insemination 44% (8 of 18) c 39% (7 of 18) c 39% (7 of 18) * one control heifer aborted between d 77 and d 107, not associated with BVD. a,b: p=0.25 c: all p<0.05 McGowan et al Vet Rec (1993) 133, 39-

25 Introducing New Animals Into a Herd Biosecurity Considerations Reduce risk for disease agent transfer from new arrivals to resident herd Reduce risk for disease agent transfer from resident herd to new arrivals It goes both ways.

26 Calf Diarrhea Introducing cattle during calving increases risk for scours Most cattle carry 1 or more scours agents

27 What risk is present for Trichomoniasis? Great calves, great cows, great bull, great grass

28 Neonatal enteritis (calf scours) prevention with the Sandhills System D. Smith, D. Grotelueschen, T. Knott, S. Ensley Applied Biocontainment

29 What should our goals be? Herd level prevention Eliminate morbidity Eliminate mortality Avoid costs Treatment Labor Reduced production losses Optimized performance $14.00 $12.00 $10.00 $8.00 $6.00 $4.00 $2.00 MED COST PER CALF commercial 1 seedstock commercial 2 $ Source: Dr. John Groves, Elton, MO

30 Effect of Calf Scours on Weaning Weight 19 pound weaning weight advantage to calves not treated for scours over those requiring treatment. 3,637 calves born Annual scour incidence range 13-64% Average annual scour incidence 35%, average annual death loss 1% Northern Agric. Res. Center, Havre, MT Anderson, et al, Prof Animal Scientist, 19:399, 2003

31 Risk Factors Affecting Diarrhea Incidence Research Results Introducing animals during calving season Calving heifers and cows in same calving area Feeding heifers and cows together

32 Risk Factors Affecting Diarrhea Incidence Research Results Extended calving season Calving more heifers in relation to cows High animal density

33 Antibodies from colostrum Immunity Active immune response Passive Age Acquired

34 Immunity Window of vulnerability Passive Age Acquired

35 Immunity Window of vulnerability Immunity Scours Exposure Age

36 Age specificity of calf scours Population at-risk for scours: calves 1-3 weeks of age Frequency histogram age of calves at death Also at-risk for shedding scours agents Count More Age at death (days) Smith, et al Bov Pract (2008) 42:1;1-9

37 Multiplier Effect Cows are shedders Calves are multipliers

38 Key Risks and Interventions to Reduce Exposure RISK: Environmental buildup of scours agents over time in calving area INTERVENTION: Planned move of pregnant animals prior to environment becoming high risk for exposure. RISK: Older calves shed lots of scours agents to younger calves INTERVENTION: Age segregation of calves.

39 Sandhills Calving System Cattle Flow Move pregnant cows in. Calve 2 weeks from Leave date pairs of first calf born Leave pairs Move pregnant Cows. Leave pairs Leave pairs Calve 1 week. Finish calving Lot 1 Lot 2 Lot 3 Lot 4 Lot 5

40 Northwest N Northeast W Move In March 1 Trees & Building Move In March 28 E A Trees Move In March 14 B Move In March 21 Leave pairs Leave pairs Leave pairs 640 A. 75 A. Develop a plan W C 125 A. S Summer Pasture 1 Leave pairs D Winter Pasture 250 A Move in March yr. olds in pasture now Leave pairs Summer Pasture A. 640 A. Move in March 7 Yearling Pasture Pivot Move in March 21 S. of House 600 A. 300 A. Old Bull Pasture 150 A. 200 A. Bldgs Old Field 3 yr olds - 60 hd. in pasture now Leave pairs Move in March 14 E S Yearling Pasture

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