Identifying health and disease in ruminants

Why is good health and disease important to the farming sector?

Good health can result in:

• Better feed efficiency

• Improved growth rates

• Higher performance

• Better welfare

• Profitability

Not an exhaustive list

Why is good health and disease important to the farming sector?

Disease can result in:

• Poor public image of farming

• Public health (zoonotic infections)

• Impacts the farmers welfare

• Poor animal welfare

• Impacts trade

• Non- profitable

Not an exhaustive list

When money is tight- disease can creep in as can’t afford to prevent/ treat

Physiological parameters of sheep/ cattle

Be aware that there are physiological parameters- there is a normal range

If an animal is outside the range then it may indicate a problem/ disease

Indicators of good health

• Alert in their behaviour, general demeanour, vocalisation

• Clear, bright eyes

• Appetite with rumination, rumen fill but no abdominal distention

*displaced abomasum- if rumen is not full it can get gaseous and can float up

• No discharge from any orifice- mouth, nose, ears, udder, genitals or anus (clear discharge is ok, opaque is problematic)

• Correct faecal consistency for diet, free from parasites

• No stiffness or lameness

• Good posture, muscle tone and locomotion

• Smooth, glossy hair or good wool/ fleece

• BCS and no weight loss

*if isolated from others- indicates potential problem

How to access the health status of farm animals

• Auscultation (heart, lungs, rumen, intestines)

*Listen to those body parts for noises

• Examination of udder and milk (assess texture of udder, consistency and colour of milk)

• Hooves: lameness/ digital dermatitis

• Visual: are they behaving ‘normally’

• Teeth: aging

• Wool quality, coat quality and hydration status of animal (skin tent test)

• Faecal consistency: is this ‘normal’ for the diet/ animal

Assessing young ruminants: weight

Youngstock up until breeding age are predominantly assessed by weight gain

• are this via BCS is more common

Dairy cattle are slightly different to beef animals and sheep

*offered straw/ pellets from beginning to stimulate rumen

• weaned ideally via a “step- down” technique when calves have at least doubled their birth weight (usually 8-10 weeks)

*step- down method- reduce milk intake over a few weeks prior to full weaning

• served at ~60% of their adult weight between 13 and 15 months

• first calve at ~85% of their adult weight between 22 and 24 months of age

Assessing ruminants: Digestion

Ruminants differ to other animals mainly due to thier GIT

Rumen, reticulum and omasum are considered fore- stomachs

Abomasum is classed as the ‘true stomach’

Pre- weaned animals use the abomasum due to their milk- based diet

Post- weaned animals eat forage/ grass- based diets due to their milk- based diet

Post- weaned animals eat forage/ grass based diets for 2-5 hours and ruminate for ~10+ hours

Rumen fill scoring used to assess and monitor feed intake in last 2-6 h and energy balance

• scores are 1-5

• Score of 3 for lactating animals

• Score of 4 for dry/ heavily pregnant

Rumen fill scoring

Rumen fill scoring used to assess and monitor feed intake in last 2-6 h and energy balance

• scores are 1-5

• Score of 3 for lactating animals

• Score of 4 for dry/ heavily pregnant

Push fist into hip area on LEFT side to assess rumen score

Always want them to be eating/ digesting never doing nothing

Assessing breeding and adult ruminants

It is common to assess adults using BCS

Performed by observation more than physical examination

Assess the covering of fat/ prominence of bones

Scale is 1 to 5 with increments of 0.25

• 1 is emaciated/ extremely thin

• 5 is obese/ extremely fat

Differs depending on stage of lactation but 2.5 to 3 is generally considered ideal for cattle

• at calving 2.5 -3

• 60 days post calving 2- 2.5

• 100 days before drying off 2.5- 3

• ay drying off 2.5- 3

Assessing breeding and adult ruminants

First time breeding stock and adults are assess on BCS and weight

Scoring again runs from 1 to 5 (increments of 0.5)

BCS measured by physical assessment of the vertical and horizontal transverse processes

• generally, a score of 3 is optimal

• ensure multiple pregnancy ewes (twins, triplets, quads) are at least a 3

• at weaning 2.5 to 3 (max) is ideal to ensure good conception rates

To increase BCS by 1 unit, animals need to gain 7-9 kg LW

It can take unto 6 weeks to increase BCS by 0.5 score

No adult animal should score less than 2.0

Mobility scoring of cattle

Healthy feet are imperative to healthy animals and great welfare

DiaryCo mobility scoring system is used for dairy cattle that runs from 0 to 3

• 0 being very good mobility

• 3 being very lame

The same scoring system can apply to beef and sheep

What causes reduction in productivity?

Farm management, animal factors and environmental factors

Intertwined factors cause problems- someone else is a problem and then pathogens get in

Infectious- parasites, viruses, bacteria, prions, fungi

Non- infectious- often genetic element or influenced by animal age and/ or environment kept in

Iceberg effect

The iceberg effect, or spectrum of disease

• a large percentage of the ‘problem’ is subclinical or unreported

• the tip of the iceberg is generally only apparent

What are the biggest financial impacts of farming ruminants?

Lameness and fertility issues

Assessing locomotion and hoof health of ruminants

Lameness

• can be infectious or traumatic

Economic implications

• huge cost to economy

Controlling lameness in cattle and sheep

• address risk factors for main cause of lameness

  • Environment

  • Breeding from sound stock with good hoof conformation

• Preventative foot bathing

• Vaccination (sheep for foxtrot but not effective)

Clinical signs

• changes in gait/ posture and weight bearing. Foul smelling foot/ feet, infection

Treatment

• antibiotics, foot trimming (cattle only), foot bathing

Footrot vaccine

9 different serotypes- vaccine has a bit of each- multivalent vaccine

this can overwhelm the immune system

best to identify what serotype and treat that 1 or 2

Lameness in cattle

Prevalence: 22- 36% of dairy cows (likely an underestimate)

Causative bacterial agents: species of bacteria belonging to the treponema genus responsible for digital dermatitis

Detection: mobility scoring and regular foot trimming

Common lesions: sole ulcers, white line disease

Lameness in sheep

Prevalence: 3.2- 4.9% of flocks (target <2%)

Causative bacterial agents: 90% of lameness is due to

• species of bacteria belonging to treponema genus responsible for CODD

• dichelobacter nodus for footrot/ interdigital dermatitus

Detection: mobility scoring and observation

Notifiable disease in ruminants

Legally obliged to report to APHA, even if it is only suspected

Notifiable diseases can be:

• Endemic: already present in UK- TB

• Exotic: not normally present in UK- FMD

• Some endemic and exotic diseases are zoonotic

Epidemiology

The study of the determinants, occurrence, and distribution of health and disease in a defined population

• used to plan and evaluate strategies to prevent illness and as a guide to the management of diseased animals

Endemic

A disease that is present but limited to a particular region

Epidemic

An unexpected increase in the number of disease cases in a specific geographical area

Pandemic

When a disease’s growth is exponential, affecting several countries and populations

Descriptive epidemiology

Used when referring to the studying of the distribution of disease

• Animal

• Place

• Time

The focus of epidemiology is on entire populations not individual animals

Analytical epidemiology

Used when referring to studying determinants of disease

• Host

• Agent

• Environment

The focus of epidemiology is on entire populations not individual animals

Distribution

The distribution of disease or descriptive epidemiology has 4 key aspects

• How many animals are affected

  • Incidence, mortality rates, and prevalence useful

• Which animals are getting the disease?

  • Breed, age, sex, species

• Where geographically are these animals?

  • Countries and disease rates

  • Locally, neighbours- raduis of control zone

  • Helps to establish if disease is endemic, epidemic, or pandemic

• Where are animals most affected or contracting the disease

  • Are there seasonal patterns

Management practices

Vital disease prevention relies upon good management practices

Most livestock disease are spread through:

• Introduction of new animals/ close contact with neighbouring animals and/ or sick animals

• Shared machinery, vehicles, equipment

• Movement of animals, people (public and workers), wildlife

• Contaminated feed and water

Reduction of disease via: herd/ flock health plans

• Staff training

• Improved hygiene and cleanliness

• Reduce stress/ handle susceptible groups first

*When walking around a farm- start at young and then go to old as to not carry disease on you from older to younger animals

• Stocking densities

• Correct nutrition at age stages

• Regular disease testing (bTB/ Johnes)

What is a vaccine?

Biological preparation that provides active acquired immunity to a particular infectious disease

Vaccination

Use of vaccines to provide herd/ flock immunity

• Over 40 cattle and 20 sheep vaccines licensed for use in the UK

• Common types of vaccine are live attenuated or killed/ inactivated

Considerations:

• Age stage of animal

• Pregnant vs non- pregnant

• When to vaccinate

What can reduce effectiveness?

• Incorrect vaccine storage

• Incorrect dosage, route or site of administration

• Poor timing of follow up booster

• Poor timing of vaccination relative to risk period

Biosecurity

Biosecurity is measures aimed at reducing and/ or preventing the introduction of new diseases into a herd/ flock

4 key principles:

• Selection of purchased animals

• Isolation of new or sick animals

• Movement controls

• Sanitation