Exam Flashcards
Q20. In an aquarium, ammonia excreted by fish is converted first to nitrite then to nitrate by two genera of bacteria attached to surfaces, gravel etc. Name the two genera of bacteria.
Nitrosomonas bacteria convert ammonia (NH3) to nitrite (NO2) and Nitrobacter bacteria oxidize nitrite (NO2) to nitrate (NO3)
These bacterial populations begin to increase as soon as fish are added to an
aquarium. Nitrifying bacteria attach to surfaces within the aquarium and require an
aerobic environment. Aquarium filters produce an expanded aerobic environment for
colonization by nitrifying bacteria.
Q21. Explain (in one sentence) the term “conditioning period” applied to an aquarium and give an estimate of the time required.
The time taken for an established population of nitrifying bacteria to cope with the conversion of ammonia to nitrite to nitrate is called the conditioning period and the established aquarium with a healthy biological filter should not have any ammonia or nitrite. (2-6 weeks)
Q22. The water in an aquarium will gradually drop in pH over time. Explain why.
The nitrogen cycle also produces hydrogen ions (H+) which produce a drop in pH. Aquariums tend to “shift acid” with time.
Q23. a) “White spot” is the name of a common disease of aquarium fish caused by a protozoan. Name the organism responsible.
……………………………………………………………………………………………………………………… b) How is a diagnosis made?
c) Name two chemicals which can be used to treat the disease.
Ichthyophthirius multifiliis or Cryptocaryon irritans (Marine White Spot)
Diagnosis- wet prep under microscope- distinctive rolling, creeping movement and rapidly beating cilia are seen
* Treatment- Formalin and malachite green, copper
Q24. Monogenetic trematodes (skin and gill flukes) are common causes of disease in aquarium fish.
i) Explain how you would diagnose infection with these parasites.
ii) List two chemicals which could be used in treating the disease.
Gyrodactylids (Body Fluke), Dactylogyrids (Gill flukes)
Itchy inflamed body and gills, body scraping or gill biopsy (or fin biopsy)– fresh wet prep under microscope
Treatment: OPs, Praziquantel
Q24.“Fin rot” is an erosive loss of fin tissue in fish and is caused by bacterial infection, mainly with Pseudomonas and Aeromonas. List two factors which predispose fish to fin rot. (2 marks)
* Predisposed by poor water quality, high organic levels, rough handling and trauma
* Fin scrape and wet smear to diagnose– by ruling out fungi lesions and external protozoa. Improve environment. Can treat with 20% Betadine solution applied to lesions twice per day. +/- antibiotics
Sudden increase in scouring and deaths in weaned pigs aged from 4-8 weeks
a) conditions would you consider could cause this
* post weaning E. coli scours (end up as coliform seticaemia), malabsorption (less likely), swine dysentery (more likely in growers), ileitis, salmonella (rare), granulomatous enteritis, PCV2
b) confirm diagnosis
* look at faeces, necropsy (E. coli fluid filled, red intestine, sunken eyes)
c) one disease how would you treat in the short term
* E. coli scours- electrolyte solution in drinkers or injection into stomach, short term you can give antibiotics, inspect 3-4 times per day
d) long term control strategies
* Better diet, Temp fluctuations minimized/ excessive air movement minimized, warm, pre-weaning vaccination, improve hygiene, all in all out, ensure not overcrowding, antibiotics in feed for the first 14 days, pulse antibiotic in water 48-72 hours prior to anticipated onset
poor growth in grower/finisher associated with coughing 15%
a) What dz conditions would you consider could cause these signs?
- Actinobacillus pleuropneumoniae– Pleuropneumonia (APP)
- Pasteurella multocida causing pneumonia
b) How would you confirm your diagnosis?
Necropsy, collect specimen for laboratory tests to confirm diagnosis
c) How would you treat one of the dz you have diagnosed in the short term?
- antibiotics empirical at first (in feed or water) then based on sensitivies (Tiamulin, Pulmotil, Lincomycin, OT)
d) What long-term control strategies for the dz would you recommend?
- vaccination, strategic medication of weaners
- for early detection check that all pigs get up to eat and move
- remove all pigs to hospital pen as soon as observed and provide treatment
- join a pig health monitoring scheme and have pigs examined regularly at slaughter for respiratory disease, proliferative enteritis, and gastic ulcers, check levels of vitamin E and selenium in diets, careful not to overstock, constant access to clean water, good temperature control with little fluctuation
Cystitis- pyelonephritis
* 3-15% death in sows
* Most cases involve ascending infection most apparent in stalled sows where hygiene is poor
* Risk of pyelonephritis increases with age– risk factors include lack of exercise and pelvic muscle tone, perineal hygiene associated with long periods of inactivity and consequent failure to void urine and flush the urinary system
* Tx must commence early- as soon as discharge or perineal staining are detected and a prolonged course of antibiotic medication (10 days) by injection or topdressed onto feed worthwhile. Long acting antibiotic injections have the advantage of requiring treatment every second day. Broad spectrum antibiotics- the tetracyclinces or amoxycillins are useful.
Three key elements about the topic and state why they are important. ID a major risk in relation to the topic and explain how you can manage this risk.
* Sedation a pet pig
- Accurate assessment of bodyweight important.
- If giving IM, can be 4 cm of subcutaneous fat. Pig veins are not very accessible.
- Butyrophenones- Azaperone (+/- ketamine for deeper sedation) (Stresnil)– most common sedative. Anxiolytic. Deep IM. Often used for castration.
Risk- secondary heat source or a blanket to keep pig warm, Azaperone causes peripheral vasodilation and so increases heat loss. Respiratory obstruction is a major concern– ET tubes and laryngoscope and a method of ventilation.
* Diagnosis of lameness in adult pigs
- The absence of deaths and of any gross lesions directs the investigation toward dietary solutions though rare in commercial pigs
- Osteochondrosis- clinical diagnoses should be supported by post mortem and radiography in pets if more definitive diagnosis is required
- With M. hyosynoviae pathogen can be cultured from joints at slaughter
Risk and how you can manage it- OCD may be congenital so care to breed it out or where you bring in stock from if therei s a problem. M. hyosynoviae– improve hygiene. Nutrition- higher quality feed, better balance- vitamin E and selenium.
Post weaning ill thrift. Mort rose from 2 to 6%
a) DDX
- E.coli scours or coliform septicaemia
- Streptococcal meningitis/ arthritis/ septicaemia
- Mulberry heart disease
- Glasser’s disease (antibiotics)
b) Confirm diagnosis
- Necropsy (MHD- severe bruising of heart muscle and increased amounts of fluid in body cavities)
c) Short term treatment
- E.coli : electrolyte in drinkers or injections into stomach cavity, antibiotics
- Streptococcal: penicillin and move to sick bay+ electrolytes if pig can’t stand
d) Long-term control
- diet, no temp flux, no excessive air movement
- Difficult to prevent Strep infections– improve ventilation, reduce stocking rate
Grower/ finisher scouring
DDX
-E. coli scours, SD, roundworm, Proliferative enteritis, Gastric ulcers
Confirm?
Necropsy, look at faeces
Treat one disease
Pulse medication in SD and PE. Olaquindox PE (continuous medication)
Long-term control strategies
- do not overstock, quality water all the time, optimal temperature range, improve ventilation, balanced diet
SICK BAY
Itchy, doesn’t appear infectious– rubbing its neck on fence posts. Likely cause? Diagnosis? Recommendation?
Sarcoptic mange
Ear scrapings or ELISA
Ivermectin- treat all of the pigs
Newborn piglets are scouring within four days of birth
a) What are some likely contributing factors?
- E. coli (first 3 days, another wave post 10 days), transmissible gastroenteritis, coccidiois (I. suis) (between 5 and 15 days), Clostridium perfringens (5-21 days)
b) How can you diagnose the cause of the scouring?
- diseases differentiated on post mortem, histopathology, culture, faecal antigen tests and oocyst detection. Diagnosis of coccidiosis is by the response to totrazuril
c) What are you going to do to treat the pigs?
- Vaccinate the sow prior to birth, if they scour now they are unlikely to scour as older piglets. Where control fails can use antimicrobial tx
- fluid therapy common to all
- sulphonamides will cover both coccidiosis and E. coli in the short term
- E. coli bacterins are based on attachment antigens
d) What are the three disease control options available to you?
- good hygiene, treatment
Q4. What are the principles underpinning a biosecurity program for a pig farm?
- do not feed swill
- minimize contact between domestic and feral animals, especially pigs and goats
- reduce the risk of spread with appropriate controls on pig
- be on the lookout for disease early and report
- controlled entrance and provision of farm boots for clothing and visitors
- training for staff on diseases
- all in all out with a good clean in between
- single source supply of breeding stock and records of pig introductions
- isolation facility
Assessing the health status of a herd
- Cough index- pigs observed in the morning, 10-20 seconds after they had been stirred. 50 pigs in pen were randomly selected and examined during a three minute period, number of pigs that coughed once or more during this observation period recorded. Useful to predict overall prevalence of pneumonia in a herd. Repeat the exercise three times and average the results. Less than 2 coughing episodes/ 3 minutes= OK. More than 10 coughing episdoes/ 3 minutes = trouble.
- Determining mortality percentage e.g. a good target is less than 0.5% deaths in grower/finishers.
- Reduced growth rate would be a major sign for diseases such as SD, proliferative enteritis, mange and resp diseases– greatest cause of financial loss– farmers end up holding onto pigs for longer or selling for less earlier. Ends up sick cycle as over crowded.
Two major risks- and management of risks
- Euthanasia of pigs
- Captive bolt- correct placement is essential, followed by severing a major artery in adult animals
- Anaesthetic overdose- difficult to place an IV in a pig, normal dangers associated with pigs
- Eradicating disease by Swiss depopulation
- All stock less than 10 months removed from facility, no farrowing for 14 days, medicate all remaining stock during this period, vaccinate breeding stock to be retained (e.g. M hyo), clean and disinfection of sheds
- Too big of a farm, success rate is low
- Costs can be high- medication, housing for removed young stock
- Farrowing crates
- increases stress levels can become susceptible to illness and stereotypic behaviours
- Poor CV health, bone density issues and poor muscle health attributed to lack of exercise
- hinged crates that only are made into a small space for 5 days post farrowing to try and prevent overlay; VIP mushroom system– can at times move around freely– spring loaded “mushrooms” encourage sow to lie down in a particular direction which provides some protection
Erysipelas control growing pigs in a bedded system
Replacements bred on the farm
Samples you would collect- kidney cortex, heart valve vegetative lesions, you could take synovial fluid if joints affected and test for E. rhusiopathiae
Tests you would do diagnosis
– treat to confirm diagnosis as diamond shaped skin lesions pathognomonic– + fever, depression, swollen joints, lameness in chronic cases
How might a presuckle serum sample from a newborn piglet in an affected litter help you?
– serology to see if antibodies in the serum from mom’s vaccination prior to birth
TX: PENICILLIN
Control: routine vaccination
A skin disease causing scabby lesions on the head and back of neonatal pigs sebaceous exudate. Mort rate high
- Aetiology- Greasy pig disease younger than 6 weeks. Staph hyicus to invade skin and result in clinical syndrome. Skin break may be caused by a virus (Parvovirus) or mechanical damage.
- Diagnosis- deyhdrated, septicaemic, greasy and cracked coat, secondary infection… Diagnosis based on gross clinical lesions, an exudative dermatitis.
- Treatment- Penicillin, amoxycillin daily for 3 to 5 days. Sprayed or dipped daily with disinfecant and oil or udder cream to keep the skin soft.
- Prevention- environmental factors such as poor sanitation and high relative humidity can contribute to greasy pig outbreaks….
- soak sows entering the farrow crates- brush and scrub
- wash all crates and disinfect
- tail and teeth clipping
Diarrhoea in 7 day old piglets
* E. coli, Clostridium perfringens, Transmissible Gastroenteritis, Coccidiosis, Rotavirus
Some abortions stillbirths and weak neonatal pigs at term in sows and gilts in a herd where white spotted kidneys have been detected in finishing pigs at slaughter
- Aetiology
- Multifocal interstitial nephritis, also called “white-spotted kidney”, corresponds to a chronic and nonsuppurative inflammation of the renal interstitium. The cause is rarely known, but in some cases it has been associated with leptospirosis and porcine circovirus type 2. (Porcine Parvovirus, PRRS)
- Diagnosis- complete history, necropsy, routine tissue for histopathology (brain, liver, kidney, heart, lung, spleen, placenta)
- Treatment- supportive, prevention is the only real treatment
- Prevention- vaccine for Leptospirosis, Parvo, PRRS, PCV2… stocking density, air quality, hygiene, concurrent infections and environmental temperature
Setting up a water medication system
* Medication can be wasted by pigs playing in drinkers, healthy pigs are treated, sick pigs may not drink… minimize hazards relating to residues in pigment.
* Proportioner pumps can deliver measured amounts of medication at a typical dilution 1:100.
* Consider weight of pigs to be medicated
* In hot weather pigs will drin kmore water and waste more water trying to keep cool– medicate pigs in cooler periods of the day +/- spray cooler
Owner of a sow herd reports a reduction in the expected number of farrowings in May, June and July. The problem is spread across all parities but gilts are more severely affected than older sows. What is happening to the herd and what can you do to prevent the problem from occurring in the future?
* Infectious infertility– Erysipelas, classical swine fever, PRRS, Porcine Parvovirus, Leptospira pomona, Toxoplasmosis, Menangle Virus, Brucellosis (uncommon)
* Diagnose the infectious disease– necropsy may be necessary, routine tissues for histopathology (brain, liver kidney heart lung spleen placenta)
* Some of these diseases become endemic after the initial infection and they become immune as well as their progeny for the first few weeks of life until about 10-12 weeks of age where passive protection has declined. Where they can develop their own immunity or become sick.
** Management practices such as all in/ all out– then a massive clean could help rid of infection.
** Stocking density, air quality, hygiene, concurrent infections and environmental temperature
** Vaccinations are available for Leptospirosis, Erysipelas, Parvo, PRRS, CSF, PCV2
Abortion, stillbirth, mummification, birth of weak piglets, anorexia and agalactia in the lactating sows, increased preweaning mortality, postweaning respiratory disease.
Piglets may be born viraemic and transmit the virus for 112 days after infection.
* Prevention: isolation and acclimitization of incoming stock
* Samples: piglets and placenta from affected litters, brain liver, kidney, heart, lung, spleen, placenta (BLKHLPS)
* how long will the disease last? can become endemic. Prevention of viral spread by nursery depopulation can be successful when virus transmission is not occurring in the sow herd– still takes 12-18 months
