Animal Diseases Exam 3

Laminitis Cont

Pain, mild to severe lameness, fever, warm feet with edema above coronary band and increased digital pulses • This is an emergency! • Subclinical laminitis (described most commonly in cattle) • No definitive clinical signs • May walk in a careful manner, narrower base stance • Chronic laminitis • Changes in hoof integrity & conformation -•Diagnose based on clinical signs, +/- radiographs • Treat with anti-inflammatory medication, +/- digital hypothermia (horses), padded foot wraps (horses), corrective trimming/shoeing • Prognosis guarded to poor, especially in horses

Vesicular Diseases

Vesicle • A liquid filled cavity under epidermis (superficial layer of skin) • A blister • Viral infections, burns (chemical or thermal), and toxin/irritant • Swine are susceptible to more viral vesicular diseases than other species of livestock • All viral vesicular diseases cause very similar lesions • It is necessary to perform laboratory tests to differentiate between them

Lameness evaulation

Visual appearance of standing animal • Assess for wounds, conformation abnormalities, and changes in stance/posture • Species will vary on normal posture • Changes can give indication of site of lesions • Observe gait at a walk (horses are also observed at different paces) on level/unobstructed ground • Most farmers will detect only 25% to 40% of truly lame cows

Rickets and Osteomalacia

• Caused by deficiencies in or issues with the relative amounts of vitamin D (lack of sunlight exposure), phosphorus, and/or calcium • Failure of proper cartilage mineralization (rickets, younger animals) and leeching of calcium from bone (osteomalacia, older animals) • Stiff gait, lameness, failure to stand, swelling of long bones, and enlargement of ribs at costochondral junction (where bone meets cartilage) • Treat with injectable Vit D/exposure to sunlight with concurrent supplementation of calcium and phosphorus

Pododermatitis Circumscripta in Cattle cont

• Commonly affects one or both lateral hind claws, predominantly in heavy, high-yielding dairy cattle kept under confined conditions • Treatment aimed at removing pressure from affected area and preventing secondary infection • Corrective claw trimming to shift weight bearing • Application of plastic slippers or blocks • Topical antimicrobials to treat open wounds • Many do not resolve

Dermatophilosis (Rain rot)

• Dermatophilus congolensis • Gram positive bacteria • Also known as streptothricosis & lumpy wool disease • Affects all ruminants, horses, and camelids • Superficial infections • Small raised crusts with imbedded fiber = "paintbrush lesions" • When crusts fall off, skin underneath is red and ulcerated +/- pus • Ears, neck, rump, back, and feet • Not itchy • Deep infections • Nodules under skin = abscesses with enlarged lymph nodes • Most common on face and feet • "Strawberry footrot" in sheep (often associated with contagious ecthyma)

Treatment of Ectoparasites cont

• Ectoparasiticides are regulated by EPA or FDA Center for Veterinary Medicine • If product is applied topically to an animal to treat ectoparasites, and the compound is not absorbed systemically, it likely falls under the jurisdiction of the EPA • No legal extra-label use of products regulated by the EPA • Powders, sprays, and dips of antiparasitics • Dust baths (diatomaceous earth, koalin clay) • If a product is administered parenterally (orally), or if it is applied topically for systemic absorption, it likely falls under the jurisdiction of the FDA • Injectable ivermectin

Interdigital Lesions in Small Ruminants

• Foot scald (interdigital dermatitis) • Inflammation, hair loss, swelling, and moisture associated with skin between digits • Skin will slough in severe cases, often precedes footrot • Dichelobacter nodosus commonly involved • Excess moisture and mud predisposing factors • Treat by improving environment + medicated footbaths • Impacted/infected oil gland in sheep • Duct can become inflamed and obstructed -> distension of gland • Treat by expressing gland contents and treating with antibiotics (prevent infection)

Laminitis

• Inflammation of laminae that bind hoof wall to bone • Attachment of epidermal laminae (connected to hoof wall) to dermal laminae (attached to distal phalanx) can break down = bone rotates/displaces • Predisposing factors include overeating or sudden access to high-grain/low-roughage diets or highprotein diets (corollary to acidosis...release of vasoactive toxins from dying bacteria) • Foot trauma - hard/abrasive flooring (ruminants), supporting limb laminitis • Septic laminitis - bacteria enter through wounds or as complication of other infections ( e.g. mastitis)

Clinical Signs

• May have history of broodiness and prolonged straining w/o producing an egg •Depressed, quiet, lethargic • Potential weakness or paralysis of legs (compression of ischiatic nerve) • Coelomic palpation • Soft or firm distension • +/- shelled egg(s)

Mites cont

• May need a magnifying glass or microscope to aid in diagnosis and identification • Some require a skin scrape to find • Deep scrape for Sarcoptes and Psoroptes • Superficial scrape for Chorioptes • Squeeze follicle to express Demodex •Number of mites ≠ severity of signs (determined by immune system's reaction) • All treated with antiparasitics • Repeated doses often necessary • Control should involve treatment of animal and environment

Contagious Ecthyma

• Parapoxvirus • Can persist in soil for years • Also known as sore mouth, orf, contagious pustular dermatitis • Primarily affects sheep and goats • Can affect other ruminants and humans (zoonotic, lesions typically on hands and face) • Typically causes vesicles (blisters) -> scab lesions lips, muzzle, ears, and in mouth • May develop on teats and udders if kids/lambs infected •Morbidity near 100% but mortality <1% • Most recover in <4 weeks • Lesions can be painful = anorexia/starvation or moms refuse to allow nursing (lesions on udder) •Transmission by direct contact and fomites • Scabs are likely infective • Typically enters through break in skin •Typically diagnosed from clinical signs but PCR is confirmatory

Vesicular Stomatitis

• Rhabdovirus, enveloped RNA viruses • 2 serotypes, no cross immunity between them • Endemic in Southeastern US with epidemics in other parts of US, typically a seasonal distribution with most outbreaks in May - Oct • Most outbreaks in cattle and horses • Also seen in pigs and rarely sheep, goats, and llamas • Horses are susceptible to vesicular stomatitis but not other vesicular viral diseases • Transmission by direct contact (with lesions) and fomites • Arthropod vectors also play a role (both biological and mechanical)

Chlamydial Polyarthritis cont

• Signs include stiffness, lameness, anorexia, fever, and a concurrent conjunctivitis • Calves usually have concurrent diarrhea • Joint swelling (less common in sheep) due to inflammation and fluid accumulation, surrounding muscles may be hyperemic (warm/red) and edematous • Diagnose with cytology of joint fluid (may see Chlamydia) and culture...needs to be specific for Chlamydia • Treatment with long acting antimicrobials in early cases may be beneficial

Epiphysitis in Goats

• Starts with bowing of one or both radii, deviation of digits -> lameness, reluctance to walk, arched back, and joint swelling • Young, rapidly growing kids or young does in late pregnancy/early lactation (heavy milkers, carrying twins or triplets) • Occurs with calcium:phosphorus imbalance, excessive protein or iron intake • Treatment is to correct imbalance • Malformations may self correct over time

Perosis

• Tarsometatarsal deformity in growing, young poultry • Luxation of gastrocnemius tendon • Rotation of leg laterally (abduction) • Impaired mobility • Deficient in manganese, choline, nicotic acid, pyridoxine, biotin or folic acid • Early treatment = reduce luxation, bandage, correct diet • Surgical options to correct exist but have a low success rate, especially in chronic cases

More Foot and Mouth Disease

• Usually accompanied by fever • Young animals may die without clinical signs of illness because of viral damage to developing heart • Zoonotic but very rare (not considered a public health issue) • Few reports of people with laboratory-confirmed cases of clinical illness 1921 - 1969 • Mild disease with vesicular lesions and influenza-like illness • Carriers • > 50% of ruminants that recover from illness and those that are vaccinated and have been exposed to virus can carry virus particles in pharyngeal region • Up to 3.5 yr in cattle, 9 mo in sheep, and >5 yr in African buffalo -• Report! • Quarantine affected animals/farm • Testing is done at very select labs • Tissue of choice for sampling is vesicular epithelium or fluid • PCR, virus isolation, serology, and antigen immunologic tests available • Vaccination is available • Subtypes differ enough that vaccines must be targeted against specific subtype involved in order to be effective control • Inconsistent protection with currently available products

Vesicular Stomatitis Cont

• Virus enters through break in skin or respiratory tract • Incubation 2-8 days • Clinical signs include fever, +/- abortion, and vesicles on feet, mouth, muzzle, vulva, scrotum, and teats • Secondary loss of appetite and lameness • Infection is transient (10-14 days), morbidity typically ~20% in a herd • Zoonotic with flu-like illness and rare vesicles -• Report! Isolate infected animals • Testing similar to FMD and differentiates between causes of vesicles •No specific treatment and no vaccination • Control of arthropod vectors, especially during outbreaks • Commercially produced vaccines are not available in USA, but vaccines for livestock are available in some Latin American countries

White Line Disease

• White line is composed of very soft keratin horn, which fills spaces between the lamella at most distal aspect of claw/hoof wall •Hemorrhage into or separation (avulsion) of claw/hoof wall, most commonly due to abnormal wall stress +/- foreign body penetration • Secondary infection with local abscess and/or infected tract (tunnel into deeper structures) formation is common

Oviduct Impaction

•Accumulation of eggs and cellular debris in oviduct •Often due to ascending bacterial infection and inflammation of oviduct (salpingitis) • Often Mycoplasma, Salmonella, and Pasteurella and E. coli • More common in older layers and those housed in dirty nesting conditions •Can occur in conjunction with oviduct cancer (typically in older birds)

Egg Cont

•Albumen • Cushions embryo • Provides protein source • Inner and outer shell membranes •Air cell • Forms at wider end of egg in separation between shell membranes • Source of air for hatching chick •Shell • Microscopic pores • Covered in proteinaceous cuticle

Chicken mite (Dermanyssus gallinae)

•Also called the "red mite" or "roost mite" •Nocturnal feeders then hide in cracks in poultry house during day •Lay eggs in environment •Can live off the bird for 2-3 weeks •Heavy infestation can cause weight loss and decreased egg production •Can cause anemia and death

White Line Disease Cont

•Cattle and horses • In dairy cattle, commonly affects one or both lateral hind claws, predominantly in heavy, high-yielding cows kept under confined conditions •May appear as a discolored (often black) mark •Need to trim away infected tissue and treat infection •Perform corrective trimming/shoeing

Lyme Disease cont- last neuromuscular disease

•Has been linked to cases of arthritis and laminitis (cattle & horses) and abortion (cattle) •Unsure of how large a role it plays in sheep/goat arthritis • Many animals have tested seropositive (have antibodies to bacteria) but few confirmed cases •Diagnosis by PCR or serology • Antimicrobial therapy recommended for clinical cases • Canine vaccination not routinely used/recommended in large animals • Vector control

General Foot Disorders

•Hoof • Overgrowth, laminitis, rot, abscesses • Skin • Rot • Foreign bodies • Rocks, plant material • Wounds • Punctures and lacerations • Abscesses • Heel bulb, interdigital gland (sheep) • Examination of foot and hoof is best done with a clean foot with a trimmed hoof/claw

Oviduct Cont

•Isthmus (75 minutes) •Short segment • Inner and outer shell membranes •Uterus/shell gland (20 hours) •Short, pouch-like segment • "Plumping" • Albumen doubles in volume with water + solutes •Calcification and pigmentation of shell membranes

Lice

•Lice infestation also called pediculosis •Mostly host specific, may survive off host for varying periods of time •Sucking lice • Mammalian parasites • Feed on the blood of their host •Chewing lice • Mammalian and bird parasites • Feed on epidermal debris, primarily skin scales, sebaceous secretions, and feathers •Live on skin/in hair or feathers •Signs include itchiness, fiber/hair/feather loss, dry scaling and redness of the skin • Sucking lice can cause anemia • Can decrease production/feed efficiency = severely itchy, eat less/move more • Infestations are more common in winter (lower temps, crowding, longer hair coat, poor nutrition) and on stressed animals

Lameness- Musculoskeletal diseases

•Local musculoskeletal disease (fracture, luxation, infection, birth defect, etc.) vs. systemic disease (sepsis, toxin, CNS disease, etc.) •Muscle and muscular attachments (ligaments) • Joints and tendons • Arthritis -> ankylosis •Bone •Feet/hooves

Otitis (Ear Infections)

•Otitis externa most common in camelids • Inflammation and infection in external ear canal •External ear canal is long and narrow • Poor drainage • Easy for material to get trapped, difficult for medications to reach •Contributing factors include skin disease around face/ears, spinose ear tick (Otobius megnini) (more common in SW US), and plant foreign bodies in ear canal •Signs include behavioral changes (head shaking, ear-twitching, scratching) • If progress to middle/inner ear infection (otitis media and interna), can develop neurologic abnormalities •Ear canal is red, thickened, +/- crusty with pus and a foul odor •Can be effectively treated if diagnosed early • Canal becomes stenotic (narrows) if chronic thickening, medications can not reach infection

Male Reproductive Anatomy Chickens

•Paired internal testes •Size and color changes in response to hormonal fluctuations • Increased volume of seminiferous tubules •Epididymis and ductus deferens •Open into urodeum of cloaca •No accessory sex glands •No phallus • Pigeons/doves •Non-intromittent phallus • Chickens/turkeys/peafowl • Intromittent phallus •Ducks/geese • Engorged by lymphatics •Most birds copulate by cloacal apposition

Chickens- Female Reproductive Anatomy

•Single functional ovary and oviduct, left side •Positioned near cranial division of kidney

Avian Reproductive Activity

•Stimulated by photoperiod (increasing day length) and... • Favorable climate (temp, humidity, etc.) • Low predation risk (low stress) • Social interaction • Available food and nest site •Photostimulation of hypothalamus -> release of reproductive hormones -> gonadal development

Lice cont

•Transmitted by direct contact and on fomites (brushes, coats, etc.) •Diagnosed by visualizing adult lice or nits •Need microscopic evaluation to ID type of louse •Treatment of affected animal(s), treatment of contact animals, environmental control, and properly addressing stressors that either permitted initial infestation or exacerbated infestation • Repeat treatment at least 2 weeks apart to kill maturing lice

Supportive Care

•Warm, dark, quiet enclosure •Fluid treatment (intravenous or subcutaneous) •Medications for pain, nutritional support, +/- antibiotics •Calcium supplementation •Necessary for uterine contraction, shell formation, etc. •Oral or by injection

Fowl Pox- Integumentary diseases

• Avipoxvirus • DNA virus in the Poxviridae family • Virus can survive in environment for long periods • Transmitted through direct contact with lesions, aerosolized virus from shed scabs, or carried by biting insects • Infection spreads slowly through flock • Cutaneous (dry) form • Nodules and thick crusts on the skin, most common on unfeathered skin of head and neck • Low mortality

Malignant Edema cont

"Braxy" • Invasion through abomasal wall • Toxemia and necrosis • Mostly seen in sheep • Very high mortality, death occurs in hours to few days • Cutaneous/systemic form can look very similar to "blackleg" and anthrax •Diagnose by culture, PCR, or antibody testing • Prevent with good hygiene and wound care after procedures

Commercial Layers

"Indeterminate egg layers" = respond to +/- of eggs during laying period by curtailing laying or laying extra eggs •Typically a 2 year production cycle •Light manipulation •Optimal diet • Lysine, methionine, calcium, and phosphorus •Ventilation and temperature control

Nutritional Myodegeneration

Acute, degenerative disease of muscle caused by a dietary deficiency of selenium &/or vitamin E in young, rapidly growing calves, lambs, and kids • Also known as white muscle disease and nutritional muscular dystrophy • Dams usually consumed selenium-deficient diets during gestation • Selenium content of pasture is lowest in spring • In US, only central region has sufficient selenium in soil • High concentrations of calcium, sulfur, and copper may decrease selenium absorption • Vitamin E deficiency occurs most commonly when animals are fed poor- quality hay, straw, or root crops • Vitamin E can also be destroyed by oxidation of feed and absorption can be disrupted with GI disease (inadequate bile salts to emulsify fats and aid uptake)

Lyme Disease

Borrelia burgdorferi • Spirochete bacteria • Transmitted by Ixodes ticks from rodents/birds to larger mammals, zoonotic • Of livestock species, disease noted in horses and cattle • Many additional mammalian and avian species become infected but do not develop overt signs

Contagious Footrot in Small Ruminants

Chronic necrotizing disease of interdigital skin +/- hoof • Gram negative anaerobic bacteria • Dichelobacter nodosus (primary) • Fusobacterium necrophorum (co-infection) • Persist on farm in subclinical, minimally affected animals • Lameness, abnormal growth of hooves, loss of condition, impaired wool production and breeding • More commonly seen in sheep than goats, occurs most often in moist dirty environments

Blackleg

Clostridium chauvoei • Naturally found in intestinal tract • Spores remain viable in soil for years • Most commonly seen in sheep and cattle • Contamination of shearing injuries, tail docking, castration site • Or via ingestion • Septicemia = some animals die with no prior signs • Fever, depression and sudden, severe lameness • Initially small, red, warm swelling in the heavy musculature that rapidly progresses to a large, black, cold swelling (necrosis) with air pockets

Swine Erysipelas cont

•Diagnose based on signs and bacterial culture of lesions •Can treat acute cases with antibiotics • Cull chronic cases as they will continue to shed large numbers of bacteria •Zoonotic •Vaccination available • Typically vaccinate sows when not pregnant • Can be used to reduce morbidity during an outbreak

Pododermatitis in poultry

• "Bumblefoot" • Lesions on underside of feet • Vary from mild erosions to full thickness loss of skin to abscesses to bony lesions • Can occur as result of injury, wet or rough footing, obesity, or an abnormal weight distribution on one or both feet • Most successful treatment results from correcting underlying issue • Other treatment options vary: • Soaks, topical creams, bandages, surgery

Vitamin E Deficiency in poultry

• "Crazy chick disease" • Encephalomalacia (swelling and necrosis of brain) • Incoordination, falling over backwards, prostrate with legs outstretched, head tilt • Exudative diathesis (leaking out of small vessels) • Subcutaneous fluid accumulation and bruising • Muscular degeneration

BBC FMD VIdeo

• 2001 UK FMD outbreak estimated to have cost the country at least $6 billion • Estimated that an uncontrolled FMD outbreak in the U.S. could cause economic losses of close to $200 billion across all economic sectors over 10 years • Loss of "FMD-free" status would shut down export markets

Pododermatitis Circumscripta in Cattle

• Also called sole ulcer • Most prevalent and costly of the noninfectious cattle foot lesions • Hole forms in sole of foot secondary to sinking of claw with subclinical laminitis • Pedal bone sinks and crushes the corium, causing ischemic necrosis (death of tissue due to loss of blood flow) • Can also be related to unhygienic conditions (wetness softens the hoof) and aggressive claw trimming

Vesicular Exanthema

• Calicivirus, non-enveloped RNA virus • Swine = vesicular exanthema • Marine animals (sea lions, seals, opal-eye fish) = San Miguel sea lion virus disease • Only ever reported in US (particularly West Coast) • Vesicles on feet and snout, in mouth, and on non-haired skin • Infection is transient • Transmitted by direct contact and fomites • Potentially transmitted by ingesting infected fish or garbage containing meat scraps from swine • Diagnosis and control similar to FMD and VS

Chlamydial polyarthritis

• Chlamydia pecorum (formerly serotype 2 of C. psittaci) • Can be recovered from feces of clinically healthy calves and lambs • Affects sheep (often lambs), calves (4-30 days old most affected), goats, and pigs • Similar strains of same organism are noted to cause abortion in sheep and cattle • Organisms shed in feces and urine, transmitted via ingestion (primarily) and inhalation • Morbidity varies 5-75%

Sheep Ked

• Melophagus ovinus • Wingless fly • Female fly deposits 1 pupa on wool • Hatches in 2-3 weeks • Only a problem in sheep • Bites and feed on blood • Can transmitted other diseases like Bluetongue • Wounds are itchy, can lead to anemia and wool damage • Transmission by direct contact • Treat with antiparasitic • Repeat in 2-3 weeks • Shearing removes majority of keds

Dermatophytoses

• More common in young animals • Also in animals that are immunosuppressed, malnourished, stressed, exposed to increased moisture • Show lambs that are shorn short and washed frequently = removes protective lanolin • Diagnose with fungal culture +/- microscopic evaluation of hair to look for fungal spores • Treatment with topical anti-fungal medication is possible but variably successful • Lesions resolve on own within months in most cases • Disinfect environment/fomites...exposure to sunlight may be helpful

Scaly leg mite (Knemidocoptes mutans)

• Tunnels into tissue under the scales of the leg (occasionally affects comb and wattle) • Entire life cycle occurs on the bird • Skin becomes thickened and crusted • May result in lameness, loss of appetite • Usually on older birds • Need a skin scrape to definitively diagnose

Cloaca

•Chamber into which the reproductive, gastrointestinal, and urinary systems empty •Opens to the outside at the vent (muscular sphincter)

Demodectic Mange

•Demodex spp. • Inflamed hair follicles (nodules) on face, limbs, back, groin area •Usually not itchy to only mildly itchy •Typically only cause signs in immunosuppressed/debilitated animals

Mites

• Parasites that live on or in skin • Feed on blood, feathers, and/or skin • Can be spread by direct contact or fomites • Some spend entire life cycle on the animal and some do not • Some are species specific (feather mites) and some are not (most of the mammalian mites)

Ca, P, and/or Vitamin D3 Imbalance in Poultry

• Particularly detrimental in young, growing birds and egg layers ("caged layer fatigue") • Lack of normal skeleton calcification • Rickets (young birds) • Osteoporosis and osteomalacia (older birds) • Fractures • Weakness, paralysis • Thin shelled eggs • Poor embryonic development

Exudative Epidermitis in Pigs Cont

•Diagnose based on lesions and bacterial culture •Treatment with systemic antibiotics and topical antiseptics •Control by improve sanitation and hygiene, washing sows before farrowing •Vaccination is possible but not common •Possible zoonotic risk

Vitamin E/Selenium Deficiency in Pigs

• Selenium requirement may increase in low protein diets (especially those deficient in sulfur containing amino acids) • Vit E less bioavailable in diets that contain high levels of vit A, polyunsaturated fatty acids, and/or mycotoxins (toxins produced by fungi) • Rapidly growing pigs, 2- 16 wks old most commonly affected • Death is rapid and often precipitated by exercise •Hepatosis dietetica • Subcutaneous edema/fluid in body cavities • Necrosis and hemorrhage of liver • Nutritional myodegeneration • Skeletal muscle degeneration (white muscle disease) • Mulberry heart disease • Pericardial sac distended with fluid, necrosis and hemorrhage of heart • Exudative diathesis •Diagnose based on lesions and testing levels of selenium/vit E in blood • Treat with supplementation (oral or injection)

Contagious Ecthyma cont

• Supportive care can be given if go off feed • Treat secondary bacterial infections with antibiotics •Use of lotions and ointments may actually delay healing • Prevention and control • Only purchase from negative herds/flocks, quarantine, avoid direct contact with other animals at shows • Vaccination can be used during an outbreak • Live vaccination • Only labelled for sheep

Footrot in Small Ruminants cont

•Diagnosed most often on clinical signs •Treatment •Hoof trimming to remove dead hoof horn and expose infected tissue to air •Medicated footbaths • 10% Zinc sulfate + 0.2% laundry detergent •Topical antimicrobical sprays • Injectable antibiotics • Run through footbath, treat with antibiotics, and then move to clean, dry pen • Prevention • Do not bring animals on to farm that have footrot or come from a farm with footrot • Quarantine • Prevent vehicular traffic from areas with known footrot • Routine foot evaluations and hoof trimmings • During wet conditions, treat sheep with medicated foot baths every 10 days (takes 14 days for bacteria to colonize) • Separate lame animals and don't return to flock/herd until footrot is gone • Effective vaccination against D. nodosus exist but it is strain specific and injection site reactions (affects carcass quality) are common • Culling of severely or chronically infected animals

Dystocia/Egg Binding

•Failure of egg to pass through oviduct within a "normal period of time" • Egg becomes "stuck" •Potential causes: • Large or misshapen egg • Low blood calcium • Obesity •Disease/trauma of uterus, vagina, cloaca, vent • Inadequate pubic distance (young birds)

Foot and Mouth Disease Cont

•Transmission: • Direct contact or aerosolized virus via respiratory secretions, milk, semen • Mechanical vectors • Air currents over land or water (reportedly 155 miles over water & 6 miles over land) • Ingestion of feed from infected animals (meat, offal, milk) • Shed in milk in cow before clinical signs develop, can survive pasteurization •Swine are "amplifier hosts" = produce larger infectious aerosols of virus than other species • Expire up to 3,000 times more virus than cattle, spread to more susceptible hosts via aerosol -• Average incubation period varies (species, route of exposure, dose, etc.) • ≥2 days for pigs • 3-8 days in sheep and goats • 2-14 days in cattle • Virus infects epithelium and vesicles develop and rupture within 48 hours • Feet, muzzle/snout, and in mouth most common • Can cause slobbers and lameness • Lesions on vulva, scrotum, and teats less common • When vesicles break open, sites are susceptible to secondary bacterial infection • Animals can lose condition and decrease productivity, which can persist chronically

Dermatophytoses (Ringworm)

•Trichophyton spp. or Microsporum spp. • Fungus, remain viable in environment for years •Circular patches of hair loss, scaling, and crusts • More evident on face/head, legs, and around anus in animals with dense fiber/haircoats • Not typically itchy •Transmission by direct contact or fomites • Isolate infected animals • Zoonotic potential

Oviduct cont

•Uterovaginal sphincter •Vagina (seconds) •Egg expulsion •Small amount prolapses during oviposition (egg laying) •Should return inside the bird almost immediately •Egg exits through cloaca/vent

Sarcoptic Mange

•Variants of Sarcoptes scabiei •Burrows into skin -> causes allergic reaction • In damp areas, can survive off host for 3 weeks •Very itchy skin lesions • Typically starts as small red lesions on head/neck • Lesions spread to rump, flank, and abdomen and become thickened and crusty with loss of hair •Zoonotic

Sex Identification in Birds

•Vent Sexing •Performed in very young chicks •Can also perform (but not usually necessary in poultry) •DNA sexing via blood • Females are heterogametic (ZW) • Males are homogametic (ZZ) •Coelomic endoscopy

Ovary

•When reproductively active, multiple ovum (yolks) develop on ovary •Release of a mature ova = ovulation •Typically next mature ova is released 30-75 min after egg is laid • Except if it is late in day, will occur next day

Sex Identification in Poultry

•Sexual dimorphism • Variations in coloring, body size, behavior, etc. between males and females • Rapid feathering to sex 1 day old Leghorn chicks • Sex-linked coloring

Abnormally Formed Eggs

•Shell (misshapen, soft, abnormal pigmentation) • Immature layers • Stress • Concurrent disease • Inappropriate nutrition, especially calcium levels •Disease in uterus/shell gland

Eggs

•Shell color genetically determined •Clutch (a group of eggs laid by a hen on consecutive days) size and number of clutches per laying cycle also genetic •Clutch size is large for commercial layers

Joint-Ill

• Bacterial septic arthritis • Staphylococci, Streptococci, Corynebacterium spp, Actinomyces spp, gram negative fecal bacteria •Disease in lambs and kids • Bacteria gain entry through umbilical stump, breaks in skin, respiratory or GI tract • Joints are inflamed = swollen, warm, and painful • +/- fever and anorexia • Navel often also inflamed • Treatment with injectable antibiotics • Prevent with repeated dipping of umbilical stump in iodine at birth, and good sanitation

Nutritional Myodegeneration Cont

• Cardiac form = heart failure (respiratory distress, cardiac arrhythmias and death within a relatively short time course) • Skeletal muscle form = stiff gait, trembling or difficulty when standing, firm muscles • Respiratory and swallowing muscles can be affected • Muscle degeneration is characterized by pale discoloration and a dry appearance of affected muscle, white streaks in muscle bundles, calcification, and intramuscular edema -• Muscle degeneration is result of oxidant damage to cell membranes and proteins, leading to a loss of cellular integrity • Both selenium and vitamin E act as part of antioxidant cascades •Diagnosis based on signs and documenting low blood or liver levels of selenium & vitamin E • Treat with injectable or oral vitamin E/selenium supplementation then correction of diet • With skeletal muscle form, improvement is evident after a few days

Chorioptic Mange

• Chorioptes spp. = chorioptic mange • Most common form of mange in US ruminants, horses, and camelids • Only some species are host specific, can survive for weeks off host • Live on the skin surface and do not burrow • Lesions typically start on lower limbs ("leg mange"), itchy + foot stomping • Usually not itchy to only mildly itchy (less pathogenic than sarcoptic and psoroptic mange)

Foot and Mouth Final

• Difficult to distinguish infected animals from vaccinated animals unless purified killed vaccines are used • DIVA (Differentiating Infected from Vaccinated Animals) • Vaccination is used more in enzootic countries to protect producing animals, because slaughter of all at-risk individuals may be economically unfeasible and can cause food shortages • Since 1982, U.S. has shared North American FMD Vaccine Bank with Canada and Mexico for use in case of an outbreak • Could only vaccinate ~14% of cattle in Texas or ~4% of pigs in Iowa • 2018 Farm Bill created a new, U.S.-dedicated National Animal Vaccine and Veterinary Countermeasures Bank, with FMD vaccine as its first priority • https://www.boehringer-ingelheim.us/news/news/foot-and-mouth-disease- fmd-vaccine-bank-what-you-need-know -• Combined use of trade and movement restrictions of animals and animal products has not completely prevented introductions of FMD into FMDfree areas • Usually controlled by: • Slaughter of all infected and susceptible animals • Strict restriction of animal and vehicle movement around infected premises • Proper carcass disposal • Environmental disinfection • Without the use of vaccines • Persistence in wildlife populations (e.g. African buffalo) can make FMD eradication unrealistic

Swine Erysipelas

• Erysipelothrix rhusiopathiae • Gram positive, rod-shaped bacteria • Organism is ubiquitous in swine/swine facilities • Shed in urine, saliva, nasal discharge, and feces • Typically seen in pigs 3 months to 3 yrs, often follows periods of stress • 3 forms: • Septicemia with purple/red discoloration of skin and death • Skin lesions = start as red discoloration, progress to diamond shaped lesions 2-3 days post-infection ("diamond disease") • Arthritis, endocarditis (lesions on heart valves), and reduced growth rate in chronic cases

Treatment of Ectoparasites

• Evaluate management and hygiene • Possible ongoing sources parasitic transfer? • Fomites, wildlife, etc. • Are there areas where parasites can hide or breed? • Is the environment appropriately cleaned prior to bringing in new animals? • Rule out concurrent disease/stress in heavily parasitized animals • Treatment for both animals and environment • Clipping long, heavily soiled, or matted coat can immediately reduce the parasite burden (for those that live on skin/in hair coat), allow topical products to be distributed evenly, and allow for treatment of secondary infections if present.

Decreased Egg Production

• Insufficient day length • Improper nutrition • Emaciation • Water deprivation • Older layers • Molt • Environmental or social stress •Disease • Systemic illness (any infectious disease) • Specific reproductive tract disorders

Lameness cont

• Lameness can be a welfare issue • Also causes stress, which can reduce immunity and productivity • Financial impact (loss of production, cost of treatment, prolonged breeding interval) • Lame cows are more reluctant to use automatic milking systems and show visible signs of stress when forced to do so •Evaluation includes examination, +/- radiographs, +/- blood work (CBC and chemistry panel to evaluate function of body systems), +/- joint aspiration

"Angel Wing" in Waterfowl

• Lateral rotation of distal carpometacarpal bone • Exact cause unknown (excess protein and energy, manganese deficiency...) • Like perosis, options exist for early treatment but their success rate is low

Digital dermatitis in Cattle

• Most common disease of feet of mature dairy cattle and is enzootic in intensively managed dairy operations worldwide • Also called hairy warts • Likely due to a combination of organisms including Treponema spp. (spirochete bacteria) and other predisposing bacteria including Dichelobacter nodosus and Campylobacter spp. • More common if hygiene is poor and footing is rough • 2 presentations: • Erosive/reactive • Proliferative (more common in North America) • Cause discomfort and lameness • Lesions most common in flexor surface of interdigital space on one or both hind feet • Topical treatment with cleaning, antibiotics, and bandaging • Injectable antibiotics in severe cases • Recurrence is typical • Control with routine foot washing, medicated footbaths, and environmental hygiene

Northern fowl mite (Ornithonyssus sylviarum)

• Most important external parasite of caged layers and breeding chickens in US • Spends entire life cycle on bird • Adults are dark red to black and barely visible • Causes soiled feathers around vent, tail, and legs •Heavy infestations can cause decreased egg production and anemia (from blood loss)

Malignant Edema

• Most often Clostridium septicum • Can occur in most species/ages • Most often associated contamination of wounds acquired during shearing, docking, or dehorning • Also associated with injections, castration, umbilical infections • Fever, anorexia, and lesions in the skin/muscle • Inflammation and edema • Soft swellings that pit when pushed on +/- gas accumulation • Muscle and skin undergo necrosis and can slough (fall off) • Infection of uterus during birth can also occur = vaginal discharge

Seneca Valley Virus

• Picornaviridae, non-enveloped RNA virus (just like FMD and SVD) • Recent outbreaks (2015) in Midwestern US • Vesicular lesions on snout and coronary band/hoof of breeding females and boars • 30-70% morbidity and mortality in <7 day old piglets infected shortly after birth • +/- diarrhea prior to death • Transmission and pathogenesis unclear • Report and testing to differentiate from other vesicular diseases

Foot and Mouth Disease

• Picornaviridae, non-enveloped RNA virus • 7 serotypes, 60+ subtypes • Affects many species of cloven-hoofed mammals • Cattle, pigs, sheep, and goats • llamas and alpacas have been experimentally infected but appear to be more resistant to natural infections • Reported in >70 species of wild artiodactyls, including bison, giraffes, elephants, and several species of deer and antelope • All age groups are susceptible, mortality most likely in young animals -• Endemic in many countries of Middle East, Africa, Asia, and in parts of South America •US is currently free of FMD • Has been eradicated here 9 times with last outbreak in 1929 • Reportable in NH (all vesicular diseases are)

Swine Vesicular Disease

• Picornaviridae, non-enveloped RNA virus • Very persistent in environment, difficult to eradicate • Swine considered only natural host • Not currently found in US (foreign animal disease) • Endemic to Italy with sporadic outbreaks in Asia • Vesicles develop on feet and around mouth • Subclinical infection can occur • Infection is transient • Most recover in 2-3 weeks • Transmitted by direct contact, fomites, and ingestion of infected tissues • Shed in respiratory secretions and feces • Differentiate from FMD

Oviduct

• Time from ovulation to lay is approx. 25 hours in chicken • Long coiled tube suspended in connective tissue • 5 parts • Infundibulum • Magnum • Isthmus • Uterus • Vagina -•Infundibulum (15 minutes) •Catches ovum •Site of fertilization •Formation of yolk membrane, chalaza, and dense albumen •Magnum (3 hours) •Longest portion •Thickened glandular wall •Deposition of albumen, Na, Mg, and Ca •Finish forming the chalaza

Dermatophilosis (Rain rot) cont

• Transmission by direct contact with animal or scabs • Predisposing factors: skin damage, excessive moisture, concurrent disease/stress, young animals • Asymptomatic carriers are common • Zoonotic potential • Identifying organism on microscopic evaluation of scab • Can also perform bacterial culture • Treatment with topical or injectable antimicrobials • Protection from wet conditions • Clipping + daily cleansing to remove crusts • Deep infections are very difficult to treat

Fowl Pox Cont

•Diphtheritic (wet) form • Plaques along linings of gastrointestinal and respiratory tracts • Can cause difficulty eating and breathing • High mortality •May result in a decrease in weight gain and egg laying in infected birds •Typically diagnosed based on characteristic lesions or biopsy • Can perform advanced viral testing (PCR, virus isolation, etc.) • Isolate infected birds • Infected birds that survive can develop protective immunity •Vaccination is possible and recommended in high risk areas • Can be performed as a preventative in young birds • Or to limit the spread of infection in a flock •No zoonotic risk

Egg

•Fertilization is not a prerequisite for egg formation •Germinal disc • Becomes embryo •Yolk • Source of minerals, vitamins, protein, and fat for embryo •Chalaza • Suspends yolk in center of egg

Equine Foot

•Foot • Hoof • Other integumentary structures (corium, skin of heel bulbs) • Laminar surface is considerably more extensive than that of ruminants • Digital cushion • Musculoskeletal structures (navicular bone, distal phalanx/coffin bone, middle phalanx/short pastern, coffin joint, associated soft tissue)

Treatment to remove Egg

•Manual expression (well shelled egg in distal tract) •Dilate + lubricate cloaca and vagina •Gentle, steady pressure cranial to egg •Ovocentesis (to collapse eggs in the tract) •Through body wall or cloaca •Large gauge needle to remove egg contents •Remove fragments or allow to pass

Blackleg cont

•Presumptive diagnose based on signs and lesions, confirm with culture, PCR, +/- antibody testing •Can be treated with wound management (if inoculation is through that route), injectable antibiotics, antiserum • Prophylactic antibiotics and antiserum particularly helpful in treating entire flock/herd during outbreak •Control with vaccination

Psoroptic Mange

•Psoroptes spp. mites •Highly contagious, can live off host for weeks •Extremely itchy with hair loss and scabs, often affects ears •Secondary bacterial ear infections possible •Very difficult to eradicate Psoroptes

Exudative Epidermitis in Pigs

•Staphylococcus hyicus •Gram positive, cocci bacteria • Virulent and non-virulent strains • Exfoliative toxins that allow rapid intradermal spread once it has penetrated skin •Also called "greasy pig disease" •Carried on gilt/sow skin or within vagina • Scrapes and bites allow bacteria to penetrate skin, leads to infection •Sudden onset of lesions in piglets (5-60 days old) •Start with a reddening of skin that progresses to pustules and vesicles • Then thin, pale brown exudate ("greasy") covers skin • Typically starts on face, almost always involves the feet •Anorexia, lethargy •Not itchy •Recovery is slow, growth rate is stunted •Morbidity of 10%-90%, mortality is typically low except in very young piglets • Incidence higher in gilt litters (no/little maternal immunity)

Mycoplasma synoviae

•Tendinitis and synovitis • Also causes a subclinical upper respiratory infection •Signs more common in chickens 4-12 wks old •Transmission • Vertical through eggs •Horizontal through contact with infected respiratory secretions •Signs include lameness and swelling of legs, joints, and foot pads -•Exudate (pus) in joints, enlarged liver and kidneys •High variation in virulence across strains • Typically low to moderate morbidity and very low mortality •Diagnosis based on signs and serologic testing or PCR •NPIP efforts have resulted in eradication of M. synoviae from most breeder flocks in US

Abnormally Formed Eggs Cont

•Yolk •Double yolk • Young birds with excessive light stimulation • Excess methionine •Yolk-less eggs • Usually formed around a bit of sloughed tissue • More common in young layers •Blood spots, discolored yolks • Stress • Nutritional imbalance • Toxins/drug administration •Albumen (meat spots, parasites) •Fatigued layers •"Lash egg" = oviductal tissue and debris •Infected/inflamed reproductive tract •End of laying cycle