David R' Smith, DVM, PhD

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Designing livestock production systems for One
Health
Planning for the health and well-being of man,
animals, and the environment

• David R. Smith, DVM, PhD
• University of NebraskaLincoln

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One Health and agriculture

• Animal health and well-being
• Human health and well-being
• Environmental health and well-being
• Food protection
• Safe (chemical, physical, microbiological)
• Secure (abundant)
• Defendable (agro-terrorism)

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One Health
Planning for the health and well-being of man,
animals, and the environment
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Selection for antimicrobial resistance
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Responsible antibiotic use education
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Veterinarians Oath
I solemnly swear to use my scientific knowledge
and skills for the benefit of society through the
protection of animal health, the relief of animal
suffering, the conservation of animal resources,
the promotion of public health, and the
advancement of medical knowledge.
AVMA, 1999
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Veterinarians Oath
I solemnly swear to use my scientific knowledge
and skills for the benefit of society through the
protection of animal health, the relief of animal
suffering, the conservation of animal resources,
the promotion of public health, and the
advancement of medical knowledge.
AVMA, 1999
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Veterinarians Oath
I solemnly swear to use my scientific knowledge
and skills for the benefit of society through the
protection of animal health, the relief of animal
suffering, the conservation of animal resources,
the promotion of public health, and the
advancement of medical knowledge.
AVMA, 1999
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Veterinarians Oath
I solemnly swear to use my scientific knowledge
and skills for the benefit of society through the
protection of animal health, the relief of animal
suffering, the conservation of animal resources,
the promotion of public health, and the
advancement of medical knowledge.
AVMA, 1999
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Veterinarians Oath
I solemnly swear to use my scientific knowledge
and skills for the benefit of society through the
protection of animal health, the relief of animal
suffering, the conservation of animal resources,
the promotion of public health, and the
advancement of medical knowledge.
AVMA, 1999
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Veterinarians Oath

• protection of animal health, the relief of animal
  suffering
• conservation of animal resources
• promotion of public health
• AVMA, 1999

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Veterinarians Oath
I solemnly swear to use my scientific knowledge
and skills for the benefit of society through the
protection of animal health, the relief of animal
suffering, the conservation of animal resources,
the promotion of public health, and the
advancement of medical knowledge.
AVMA, 1999
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Ashland County, OH
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good surroundings and clothing, fresh air,
spirits of mindererus, sweet spirits of nitre,
tempting food, nux vomica, tonics, nutritious
food
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Dr. Hess Distemper, Fever, and Cough Remedy will
be found very beneficial in these cases
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Causal theoryHow do you know if a drug or a
vaccine works, or if a management practice causes
an animal health/performance effect?How do you
decide about acting on the information?
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Evidence-based medicine

• Time order
• Magnitude of association
• Consistency
• Biological gradient (dose effect)
• Coherence (biologically plausible)

Clinical Trials Process
Proof of concept
Safety, Immune response, Challenge studies
Safety, Dosage, Limited field studies
Does it really work? Large numbers
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Veterinarians Oath
I solemnly swear to use my scientific knowledge
and skills for the benefit of society through the
protection of animal health, the relief of animal
suffering, the conservation of animal resources,
the promotion of public health, and the
advancement of medical knowledge.
AVMA, 1999
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Neonatal calf diarrhea Death loss Performance
loss Treatment costs Labor,
medication Human toll Risk for injury,
frustration
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Neonatal calf diarrheaPublic Health Concerns
Zoonoses Salmonella
Cryptosporidia Antibiotic usage
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Sandhills Calving System reduces scours
Successful Farming John Walter and Betsy Freese
Jan 25, 2006

• In about an hour, Terry Clements finishes a
  chore that has helped cut calf scours on his Loup
  County, Nebraska, ranch to nonexistent

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The Principles of Animal Hygiene and Preventive
Veterinary Medicine

• The faith in cures and the practice of
  dealing with disease problems only after they
  have arisen, which thousands of years of magic
  and dosing have firmly establishedis
  antagonistic to disease prevention
• Leunis Van Es
• Lincoln, NE 1932

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Great advances in medicine
Kochs postulates of infectious disease causation
Flemings discovery of penicillin
Pasteurs pioneering work in germ theory and
immunology
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Great advances in medicine
Hippocrates 400 BC On Airs, Waters, and Places
Dr. John Snows pioneering work in modern
epidemiology
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John Snow, London cholera epidemic,1854
remove the handle from the Broad St. pump
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The McLean County System of Swine Sanitation

• Management system to control internal parasites
  of young pigs
• Based on farrowing hygiene and movement of sow
  and pigs to clean pastures
• Tested 1919-1926
• Reviewed- 1942 USDA Yearbook of Agriculture.
  pp774-780

A
A. These large, healthy pigs were protected
from the ravages of parasites B. These unthrifty
pigs became parasitized soon after they
were born
B
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Nebraska Field Disease Research Diagnostic
investigation Field epidemiology Case-studies of
interventions
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Agents

• bacteria
• E. coli, Salmonella
• viruses
• rotavirus, coronavirus
• protozoa
• cryptosporidia
• fungi
• mycotic superinfection

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Agents of calf scours

• Diarrhea-causing organisms are common in cattle
  populations
• including herds without scours problems.

bovine coronavirus
cryptosporidia
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The battle between exposure and immunity begins
at birth
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Immunity
Antibodies from colostrum
Age
Passive
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Immunity
Active immune response
Antibodies from colostrum
Age
Passive
Acquired
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Immunity
Window of vulnerability
Age
Passive
Acquired
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Immunity
Window of vulnerability
Scours
Exposure
Age
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Immunity
Scours
Exposure
0-5 6-10 11-15 16-20 21-25
26-30
Age in Days
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Age specificity of calf scours

• Population susceptible to scours calves 1-3
  weeks of age

Also when calves become infective
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Nebraska Sandhills
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The Nebraska Sandhills consists of 19,600 square
miles of sand-dune formation covered by native
grassland.
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Nebraska Sandhills
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Arthur County, NE402 people/718 sq. mile (2004
est)29,705 cattle and calves (2002 USDA)
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Beef herd experiencing severe losses to calf
scours

• 402 cattle with live births, managed as a single
  group intensive grazing
• No treatment or control interventions
• 48 deaths due to scours
• An epidemiologically-pure scours epidemic
• and RECORDS!

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Factors of the calf explaining death from scours

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Factors of the calf explaining death from scours

• Calves born on the day of a pasture-move were
  more likely to die (OR1.9, p0.09)

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Age of the calf at death
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Age of death over time
Death in the same age-range throughout the
calving season
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Size of the at-risk population
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Weekly rates of mortality
Force of disease
neonatal diarrhea deaths / at-risk
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Proportion of the calves born each week that
eventually died from neonatal diarrhea
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• Levels of pathogen exposure increase over TIME
  within a calving season

• Increasing ANIMAL DENSITY (more effective
  contacts and environmental contamination)
• MULTIPLIER EFFECT
• Cows - low level shedders
• Calves multiply pathogens to higher and higher
  levels resulting in greater infectivity

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Multiplier Effect
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Biocontainment strategies for neonatal calf
diarrhea

• Eliminate the agent and keep it out
• Increase host resistance
• Colostrum!
• Prevent effective contacts older infective
  calves and contaminated environment!

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Sandhills Calf Scours Project
Frequency of births
120
100
80

• Re-create the conditions existing at the start
  of the calving season
• Clean calving area
• Absence of older calves as a source of exposure

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Count
40
20
0
5/1
5/8
5/15
5/22
5/29
6/5
6/12
6/19
6/26
7/3
More
5/2
5/9
5/16
5/23
5/30
6/6
6/13
6/20
6/27
7/4
Date
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Sandhills Calf Scours Project
Frequency of births
120

• Re-create the conditions at the start of the
  calving season
• Move pregnant cows to new calving pastures each
  week
• Minimize dose-load
• Improve maternal bonding
• Segregate calves by age to prevent the multiplier
  effect

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80
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Count
40
20
0
5/1
5/8
5/15
5/22
5/29
6/5
6/12
6/19
6/26
7/3
More
5/2
5/9
5/16
5/23
5/30
6/6
6/13
6/20
6/27
7/4
Date
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Sandhills Calving SystemWeek 12
Calving Pasture
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Sandhills Calving System Week 3
Calving Pasture
1-2 week old Pairs
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Sandhills Calving System Week 4
1 week old pairs
Calving Pasture
2-3 week old pairs
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Sandhills Calving System Week 5
2 week old pairs
1 week old pairs
Calving Pasture
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Sandhills Calving System Week 6
Calving Pasture
2 week old pairs
1 week old pairs
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Sandhills Calving System Week 7
Calving Pasture
1 week old pairs
2 week old pairs
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Sandhills Calving System Week 8
Calving Pasture
1 week old pairs
2 week old pairs
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Sandhills Calving System Week 9
Calving Pasture -Finish out
1 week old pairs
2 week old pairs
Groups commingled after youngest calf is 4 weeks
of age
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Develop a plan
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• Less death and illness due to neonatal scours
  (plt0.01)
• Minimal to no treatment or antibiotic use
• 24-fold reduction in animal health expenses
  (plt0.01)

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Sandhills Calving System reduces scours
Successful Farming John Walter and Betsy Freese
Jan 25, 2006

• "This is the number one thing I've done over the
  years that has benefited us economically,"
  Clements says.

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Veterinarians Oath
the protection of animal health, the relief of
animal suffering, the conservation of animal
resources, the promotion of public health

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Systems to prevent neonatal calf diarrhea reduces
the need for antibiotics

• Calf hutches on dairies
• Sandhills Calving System in beef herds

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Weaned calves

• Respiratory disease
• Weaning and commingling

• Liver abscesses
• Adaptation to new rations

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Backgrounding strategies can reduce the need for
antibiotics later

• Low-stress weaning
• Pre-stress vaccination
• Easy adaptation to new diets

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Dairy cattle

• Mastitis
• Contagious
• Environmental
• Lameness
• Nutrition
• Trauma

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Better diets, comfort, and sanitation prevent
mastitis and lameness and reduce the need for
antibiotics
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Milk quality is better today than it ever has been
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The Principles of Animal Hygiene and Preventive
Veterinary Medicine

• those more particularly concerned with the
  food-producing animals must think in terms of
  hygiene, for their success is in no small measure
  dependent upon their knowledge of the subject
• Leunis Van Es Lincoln, NE 1932

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