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Herd and Flock Health Programs: Part 1

Christine B. Navarre, DVM, MS, DACVIM
Extension Veterinarian
Louisiana State University Agricultural Center
Baton Rouge, LA 70803
cnavarre@agcenter.lsu.edu

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Health Programs
- A vaccination program is not a herd health program
- Don’t try to vaccinate you way out of a disease problem
- Good management = good health
- Attack from multiple points
- Ex. Sandhills calving system
- Ex. Butt detail

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Herd Health Plans
- Much more than disease protocols
- Replacement female management
- Male development and soundness
- Nutrition
- Genetics

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Tip of the Iceberg
- Most diseases (infectious and non-infectious)
- Ratio of clinical to subclinical
- 1:5 to 1:20
- So cost of subclinical greater than clinical
- Parasites perfect example
- Because most diseases are subclinical, the occurrence of clinical cases usually indicates some type of management/husbandry stress

Clinical
Subclinical

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Anaplasmosis
- About one death per year average (tip of iceberg)
- 2-5% decrease in reproductive efficiency (underwater)
- 50 lb loss of weaning weights in calves nursing subclinical cows (underwater)
- Vaccine about 10USD/dose (20USD first year)
- 100 cow herd = 1000USD per year
- One dead cow and 2 less calves weaned will pay for vaccine

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Costs of replacing death losses
- Purchase cost
- Increased risk
- Production potential unknown
- Disease introduction

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Necropsy
- A dead animal is the most important animal on the farm that day

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Pharmaceuticals
Prudent Use-After the fact
- Disease factors
- Pathogen
- Location
- Chronicity
- Therapy factors
- Pharmacokinetics
- Pharmacodynamics

Stewardship- Preemptive
- Animal factors
- Husbandry
- Stress
- Biosecurity
- Environment
- Immunity
- Vaccinations
- Genetics
- Physiologic State

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Herd Health: The Numbers
- Economic figures available
- Often averages
- From other regions
- Different herd sizes
- Economic return vs. risk management
- Implant/deworm vs. vaccinate/single use needles
- Records
- The faintest pencil is stronger than the strongest mind

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Herd Health Calendar
- Should be tailored to the operation
- For example -in Louisiana (Subtropical)
- Start with parasite control unless disease issues on farm
- Then add vaccinations
- Work in castration/dehorning/implanting, palpation, fly control, etc.

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Herd Health Calendar
- Some things may not fit
- Anaplasmosis vaccine should be given in the spring
- Fluke treatment in fall

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Efficiency
- Timing is critical
- If you are going to spend the money, use the product at the best time
- Deworming
- Vaccination
- Gathering animals costs money, risks injury

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6 Parts of a Herd Health Program
- Nutrition
- Parasite Control
- Biosecurity
- Vaccinations
- Genetics
- Manage stress

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Nutrition
- If nutrition is optimized, health and production will be also
- If it is not optimized, diseases and production losses WILL be a problem
- Poor nutrition (protein, energy, vitamins, minerals) depresses immunity to diseases
- Poor nutrition interferes with response to vaccination
- Do not attempt to chase a disease problem without also addressing nutrition
- May find, eliminate, and vaccinate for a disease, but another will take its place

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Animal Nutrition Requirements
- Depends on:
- Stage of life
- Breed
- Genetic potential
- Desired output
- Cow condition
- Pregnancy status

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Nutrition
- Energy, protein, vitamins, mineral, water
- Follow NRC Requirements
- Changes depending on stage of production
- Impacts
- Production
- Immunity
- Carcass characteristics
- Immune function, growth and fertility are depressed before clinical signs are evident

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Priorities
- Livestock producers are really grass farmers!
- Economical production is based on economical feeding
- Need to minimize swings in body condition

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BCS (Nutrition) Will Impact
- Conception / Pregnancy Rate
- Date of Conception
- Level of Dystocia
- Youngstock Health and Vigor
- Preweaning Performance
- Postweaning Performance

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Fetal Programming (Developmental Programming)
- The concept that a maternal stimulus or insult at a critical period in fetal development has long term impacts on offspring
- Nutritional stress most studied
- Humans
- Malnurishment in first half of pregnancy
- Offspring have increased incidence of diabetes, obesity, CV disease, behavioral problems
- Two mechanisms
- Direct damage to tissue/organ structure (one off)
- Epigenetic changes (potentially multigenerational)

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Critical Period of formation of Fattening, intramuscular
Intramuscular adipocytes adipocyte hypertrophy
Intramuscular fat
Other fat depots

Conception Mid-gestation Birth 250d Slaughter

Adipocyte hyperplasia Adipocyte hypertrophy

Min Du, et al., 2015

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Fetal Programming-Cattle
- Nutritional stress-mainly protein
- 1st and 2nd trimesters (coincides with high lactation demands)
- Organ development and vascularization/placental development
- Reduced caruncular and cotyledonary weights
- Reduced fetal weights
- Number of oocytes available for life
- Respiratory disease increased

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Epigenetics
- Genes that are inherited are either turned on or off
- Can be passed on to next generations
- Adverse long-term effects reflect a mismatch between fetal environmental conditions and the conditions that the individual will confront later in life

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