PAHD - health and disease in pigs

What does AMR stand for?

anti-microbial resistance

why does anti-microbial resistance occur?

if antibiotics are over used

what happens to trade if there is poor health and disease management?

reduces UK and global trade

what does good health of animals result in?

• better feed efficiency

• improved growth rates

• higher performance

• better welfare

• greater profitability

• more animals/pigs

• better public perception

what does disease in animals result in?

• poor public image of sectors

• reduced public health if zoonotic infections

• increased antibiotic use and AMR

• poor animal welfare

• impacts on trade and profitability

• reduced production

what is the normal heart rate of a pig?

70-80 bpm

what is the respiration rate of a sow?

10-20 breaths per minute

what is the respiration rate of a piglet?

20-40 breaths per minute

what is the rectal temperature of a pig?

39

key signs of good health of a pig?

• alert in behaviour

• clear/bright eyes

• no discharges from mouth, nose, genitals or anus

• smooth skin/hair

• no stiffness or lameness

• upright or curled tail

how do people normally measure weight of pigs for breeding and finishing?

BCS as it is most accurate

how do you normally weigh weaners and growers?

in kg

what is feed conversion ratio?

amount of feed needed to produce 1kg of weight

where are the prime areas of a pig to BCS?

hips and along the spine

why is BCS important in breeding and finishing pigs?

BCS considers both weight and backfat thickness

and pigs with same weight might have different fatness due to being longer or taller

what happens to over-conditioned (4.5/5) sows entering farrowing?

• may suffer dystocia

• will have lower feed intake

• rely on own fat reserves to produce milk

• extra strain on legs and joints

what happens if a sow is under conditioned (<2.5)?

• may not maintain pregnancy

• reduced milk yields

• may have delayed oestrus post partum

• fewer piglets alive

what will both over and under conditioned sows result in?

• leave farrowing having lost BCS

• requires more inputs to get back to 3 BCS

• have decreased number of born in subsequent litter

what are the indirect effects of disease?

• decreased daily live weight gain

• decreased FCR

• increased mortality

• increase in uneven pigs

• increased drug costs

what antibiotic is not used in pig production and why?

colistin due to the high importance in human medicine

what was zinc oxide used for?

post-weaning scours

what does epidemiology mean?

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

what is epidemiology used for?

used to plan strategies to prevent illness and manage animals

what is an endemic?

a disease that is present but limited to a particular region

what is an epidemic?

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

what is a pandemic?

when a disease grows exponentially, affecting several countries and populations

when is descriptive epidemiology used?

the distribution of the disease

animal, place and time

when is analytical epidemiology used?

the determinants of the disease

host, agent, environment

what are the key 4 aspects of distribution of the disease?

1. how many animals are affected - incidence and mortality

2. which animals are getting the disease - sex, breed, species

3. where are the animals geographically

4. when are animals most affected or contracting the disease - seasonal patterns

does African swine fever affect all pigs?

yes

is African swine fever zoonotic and notifiable

not zoonotic but is notifiable

what are the main clinical signs of African swine fever?

• fever

• depression

• recumbency

• loss of appetite

• sudden death without signs

how is African swine fever transmitted?

• infected meats/meat products

• contact with infected pigs, bodily fluids and faeces

• contact with anything contaminated - people, equipment and vehicles

does African swine fever survive in cooked and frozen meat?

yes

has African swine fever ever been in the UK?

no but is in Europe

what does notifiable disease mean?

legally obliged to inform APHA even if disease is only suspected

what are the notifiable diseases of pigs in the UK?

• foot and mouth

• classical swine fever

• swine vesicular disease

• porcine epidemic diarrhoea

• bovine TB

• anthrax

what are the four common body systems that are affected by disease?

• musculoskeletal

• respiratory

• gastro-intestinal tract

• urogenital tract

what is the main musculoskeletal issue?

lameness

what are the main causes of lameness in pigs?

management and bacterial aetiologies

what are the issues with lameness?

• painful, distressing

• eat less

• reduced productivity

• reduced fertility

• more likely to be culled

• loss of animals

when do sows become profitable?

not until the 3rd litter

what flooring causes issues with pig joints?

slatted flooring and hard floors with no straw causes stress on the joints

what is important to get right with slatted flooring?

the width between the slats

how does nutrition affect lameness?

lack of/incorrect nutrition impacts muscle and bone structure

what are the risk factors for musculoskeletal issues?

• flooring

• housing system

• stocking density

• group size

• growth rate

• nutrition

what is bacterial arthritis caused by?

• streptococcus suis

• Actinobacillus suis

what are the six ways to reduce bacterial arthritis?

• teeth clipping

• colostrum management

• iron

• navel treatments

• intercurrent diseases (PRRSv)

• creep feed quality and temperature

how can teeth clipping reduce the incidence of bacterial arthritis?

stop teeth clipping, check piglets mouth and teeth clipping equipment as the bacteria colonise in the upper nasal cavity so lack of disinfectant can cause transfer

how can colostrum management reduce the incidence of bacterial arthritis?

increase colostrum intake and check by blood/serum TP evaluation

how is iron involved in the incidence of bacterial arthritis?

anaemia can be immunosuppressive

hygiene of iron injector going from piglet to piglet

how do you look after the naval to prevent bacterial arthritis?

dip naval with iodine as bacteria can track up

how does state of creep feed influence bacterial arthritis?

creep feed temperature and draughts cause issues as piglets have little adipose tissue for warmth

what other disease present will cause bacterial arthritis?

PRRSv

what type of bacterial is steptococcus suis?

bacterial gram positive commensal of the URT of pigs and is zoonotic

what are the common disease caused by streptococcus suis?

• bacterial arthritis

• sepsis

• endocarditis

• meningitis

• pneumonia

what are the transmission risk factors of streptococcus suis?

• overcrowding

• poor ventilation

• excessive temp fluctuations

• mixing of pigs with age gap of over 2 weeks

• coinfections

what is the treatment and control of streptococcus suis?

• antimicrobials - beta lactams and penicillin

• vaccines are partially effective for some strains

how is streptococcus transferred to humans?

raw meat or bitten by infected pig and it enters the blood stream

what are the main causes of GIT issues in neonates?

• colibacillosis

• coccidiosis

• clostridial enteritis

• rotavirus

• coronavirus

what is swine dysentery caused by?

microaerophilic spirochaete brachyspira hyodysenteriae

what does swine dysentery cause?

• weight loss and productivity

what does swine dysentery cause in 6-14 week old pigs?

muco-haemorrhagic colitis - swelling of the colon membranes

how is swine dysentery diagnosed?

laboratory diagnosis by culture and/or PCR of Brachyspira hyodsenteriae

how is swine dysentery transmitted?

infected pigs, their dung and anything infected by their dung

can swine dysentery spread between farms?

yes due to lack of biosecurity

what happens to pigs growth after being treated for swine dysentery?

take longer to reach slaughter weight

what is a problem with the treatment of swine dysentery?

resistance to the limited range of treatment is increasing

why is swine dysentery difficult to control?

• faecal-oral infection and incubation period may be 7-60 days

• carriers may remain sub clinical for up to 90 days

• organism can survive in moist faeces for 40 days at 5⁰C and 60 days if diluted in tap water

what can be the reservoirs for swine dysentery?

pig manure and slurry, farm dogs, rodents, birds (seagulls/starlings) and flies

how do you kill swine dysentery in the environment?

dry warm conditions and disinfectants

what are the prevention methods of swine dysentery?

• avoid vehicles coming through farm gates

• implement vehicle washing standards

• rodent control

• movement of pigs onto/off farm

• control of visitors

how to treat swine dysentery with antibiotics?

• minimum inhibitory concentration is done before antimicrobial treatment

• antimicrobial treatment early and water medication preferred

what are the commonly used drugs for swine dysentery?

pleuromutilins, carbadox, lincomycin and tylosin

how can the expression of swine dysentery be influenced by diet?

• can be reduced through alteration of fibre to more soluble fibre such as sugar beet pulp

• reduce feed components such as distillers dried grains

problems associated with respiratory issues?

• reduced growth rates

• reduced FCE

• variation in back fat

• increased trimming at abattoir

how many infectious agents are involved in respiratory tract infections?

more than one such as viral and bacterial

are respiratory tract infections contagious and how do they spread?

highly contagious and spread direct by aerosol or indirect by birds and vehicles

what does URT stand for and what does it contain?

upper respiratory tract and compromises of the nose, nasal cavity, mouth, throat (pharynx) and voice box (larynx)

what does LRT stand for and what does it contain?

lower respiratory tract and compromises of the trachea and the lungs - bronchi, bronchioles and alveoli

What is the surface lined with in the trachea, bronchi and bronchioles?

a film of mucous which is continually moved upwards to be swallowed or ejected

how does dust and microbes get cleared from the airways?

stick the the mucous film

how does the alveoli protect itself from invading pathogens?

immune cells can attack the pathogen and prevent damage and systemic infection

what does PRDC stand for?

porcine respiratory disease complex

when does PRDC normally occur?

14-20 weeks of age or 8-10 weeks after moving to the finishing unit

what are the clinical signs of PRDC?

• lethargy

• anorexia

• fever

• nasal discharge

• ocular discharge

• coughing

• laboured breathing

• purple discolouration of skin, especially ear tips

what are the viral agents involved in PRCD?

• PRRSV

• coronavirus

• swine influenza virus

• circovirus (PCV2)

which virus causing PRCD are DNA, RNA, enveloped or non-enveloped?

PRRSV = enveloped ssRNA virus

PCV2 = non enveloped ssDNA

what are the bacterial agents involved in PRCD?

• mycoplasma hyopneumoniae

• streptococcus suis

• actinobacillus suis

what are the management factors to prevent PRDC?

• limit movement of pigs

• limit overstocking based on pig size/weight

• vaccination for PVC2 and PRRSv in place

• avoid mixing of different groups of pigs

what are the environmental factors that can be controlled to prevent PRDC?

• monitor temperature in buildings daily and avoid temperature fluctuations (± 2)

• humidity below 70% by good ventilation

• avoid excessive ammonia levels (<50ppm) by good ventilation

• reduce ascaris larval migration by implementing a worm control plan

what are the signs of urogenital issues?

• reproductive failures and performance

• affects male and female reproduction

• irregular return to oestrus and number of litters decreases per year

• weak and premature piglets

• mummified foetus

what are the most common causes of urogenital infections?

• PRRSV

• stillbirth mummified embryonic death infertility (SMEDI)

• swine influenza A

what are the clinical signs of PRRSv in weaners?

loss of appetite, dullness, reddening of the skin, laboured breathing, rough hair and failure to thrive

what are the clinical signs of PRRSv in gilts/sows?

slow return to oestrus, premature farrowing, mummified foetuses, stillbirths and high pre-weaning mortality

what happens to injection sights and ears when a pig has PRRSv?

bruising at injection sites and ears due to lack of oxygen

how is PRRSv introduced into the herd?

• replacement pigs

• vectors such as flies and slurry

• aerosol over short distances

how can PRRSv be transmitted?

• by nose to nose contact

• from sow to piglet during pregnancy

• by contaminated needles

• through saliva and blood

• by close contact with slurry or infected carcass

• in semen

• by birds or insects

• on contaminated clothes

does PRRSv survive well outside the host?

no

what are the control methods for PRRSv?

• have a closed herd

• introduce screened animals

• isolate new animals

• routine vaccination if farm is at high risk area