pigs

Question 1

pig biology

Answer 1

• reach maturity at ~ 6 months of age, live up to 6-10 yrs
• litters 9-13 piglets (commercial breeds)
• similar biologically to humans
  - simple/monogastric digestive system
  - immune system
  - organs
• dry skin

Question 2

pig behavior

Answer 2

• intelligent – easily trained, excellent hearing and sense of smell
• social animals – house in groups, have a social hierarchy
• behaviors
  - running
  - scratching
  - swimming
  - mud baths

          - no sweat glands ➞ sensitive to heat stress
          - thermoregulation
          - parasite control

Question 3

pork production

Answer 3

• pork is the most consumed meat in the world
• US = 3rd largest producer/consumer of pig products, largest exporter of pig products
• production – mostly indoor confinement = highly controlled, reduced disease risk, but high density (therefore disease outbreaks a concern)
• US – 60,000 commercial pig farms
• 115 million pigs produced each year

Question 4

pig operations

Answer 4

1. farrow-to-finish (all in one operation)

          - breeding and farrowing sows 
          - feed offspring to market weight – 280 lbs 
          - 10-month cycle 
          - expensive, labor intensive

2. farrow to feeder

            - gestation to nursery phase 
            - sold for finishing 
            - reduced operations
            - more economic but less profit
                    - less need for machines ➞ less cost investment 

3. **feeder to finish **

            - finishing operation 
            - reduced operations (don’t manage breeding stock) 
            - lower labor requirements
            - more disease risks ➞ purchase from multiple farms, transportation, risk factors

Question 5

coccidiosis host

Answer 5

• commercial production & backyard pigs
• young piglets (farrowing >10d old)
• intestinal — damages G.I. tract
• subclinical on most farms
• sows don’t get sick ➞ sub-clinical

             	· carriers
        		· bring into farrowing facility 

• not all piglets exposed will get it
• must be a stressor: smaller, poor immune function more susceptible

Question 6

coccidiosis agent

Answer 6

• protozoa, genus Eimeria (many species)
• horizontal transmission: vehicle (feces) & fomites
• vertical transmission: mother to offspring
• pig-specific

Question 7

coccidiosis envir

Answer 7

• biosecurity:

  · cleaning/disinfecting areas btwn litters 
  · quarantine 

• D+ piglets need warm, comfortable envir

            · easy access to warm milk
            · supportive care

Question 8

coccidiosis clinical signs

Answer 8

• diarrhea @ 10d
• lethargic
• weight loss or no weight gain
• dehydration

Question 9

coccidiosis dx

Answer 9

• visual inspection of piglet’s clinical signs
• Necropsy - Visual inspection of the intestines (dead pig)
• cannot diagnostically test while alive

Question 10

coccidiosis tx

Answer 10

• anti-coccidial agents for piglets – poor efficacy, but may help if provided before GI tract damage
• antibacterial agents – not practical because of meat withdrawal period of many months
  - production meat cannot contain antibiotics for a set # of mo
• anti-coccidial disinfectants – clean between litters
  - most effective
  - easy access to milk, probiotics may help but unclear

Question 11

streptococcus suey host

Answer 11

• very common in both commercial & non

            - more so in commercial ➞ confined indoor housing 

• nursing & newly weaned
• worldwide

            - found in all major producing facilities & countries
            - very prevalent in Asia
            - somewhat prevalent here

• zoonotic: common for butchers, farmers & vets to contract
• mature pigs not usually affected ➞ must have underlying stressor

Question 12

streptococcus suey agent

Answer 12

• bacterial pathogen streptococcus suey
• can be clinical or sub-clinical
• transmission:

  - direct horizontal: nose to nose contact
  - direct vertical transmission
  - indirect horizontal: 
    
                       ➝ vehicles — fomites
                       ➝ mechanical — flies & rodents

Question 13

streptococcus suey envir

Answer 13

• biosecurity protocols: disinfectants kill bacteria
• housing density
• reducing stressors

            - aggression
            - ventilation 
            - humidity & temp

Question 14

streptococcus suey clinical signs

Answer 14

• inappetence
• weight loss or not gaining weight
• fever, inflammation
• lethargic
• arthritis
• pneumonia
• shaking/convulsing ➞ it’s close to death

Question 15

streptococcus suey dx

Answer 15

• swab nasal cavities/tonsils - present without clinical infection therefore challenging to diagnose
• clinical signs and analyze farm records to assess risk factors

            - # impacted
            - age impacted
            - # morbidity/mortality
            - envir parameters:
                    ⇾ temp
                    ⇾ humidity
                    ⇾ stocking density

• necropsy - tissue sample, bacterial culture, and PCR testing

Question 16

streptococcus suey tx

Answer 16

• resistant to antibiotics ➞ no highly effective treatment options
• prevention is key – eliminate stressors in young pigs, biosecurity, control of other diseases
• developing vaccine:

            - give to mother ➞ vertical transmission through antibodies in colostrum until 4w
            - bacterial gene sequencing

Question 17

porcine reproductive & respiratory syndrome (PRRS) agent

Answer 17

• PRRS Virus (genus Arterivirus)

                - PRRSV-1 (European origin)
                - PRRSV-2 (N. American origin)

• clinical presentations:

                - breeding animals ➞ reproductive impairment
                - all pigs/ages ➞ resp disease

• very infectious
• vertical transmission
• horizontal transmission:

                - vehicles ➞ fomites, semen, food, water

Question 18

porcine reproductive & respiratory syndrome (PRRS) host

Answer 18

• commercial production
• all ages
• worldwide
• prevalent in US
• sow can contract during breeding &
  artificial inseminations
• most infected pigs become immune

Question 19

porcine reproductive & respiratory syndrome (PRRS) envir

Answer 19

• biosecurity btwn age groups
• quarantine/test new animals
• vx ➞ not very effective
• early weaning & isolation of new liters
• no mixing ages

Question 20

porcine reproductive & respiratory syndrome (PRRS) clinical signs

Answer 20

• fever
• lethargy
• poor growth
• dyspnea, sneezing
• vomiting (older animals)
• reproductive problems ➞ no other disease shows this ➞ key clinical sign for identification

            - premature
            - stillborn
            - mummified fetus
            - weak piglets 

• 2° infx ➞ infected with other pathogens (virus, bacteria)

  - ex: influenza, porcine respiratory coronavirus, Mycoplasma hyopneumoniae

Question 21

porcine reproductive & respiratory syndrome (PRRS) dx testing

Answer 21

• blood sample ➞ PCR or ELISA test

            · ELISA test: antibody test
            · PCR: detects genetic material

• necropsy – tissue sample (lung preferred), PCR or ELISA

Question 22

porcine reproductive & respiratory syndrome (PRRS) tx

Answer 22

• no effective treatment
• exists on most farms
• reduce severity

            - improve comfort
            - easy access to food/water 
            - ↓ stress

• reduce number of infections

            - ↓ stocking density 
            - improve biosecurity measures

• establish a control program & monitor disease
• need more research