Comprehensive Veterinary Herd Health: Dairy, Small Ruminant, and Poultry Systems

Comprehensive vocabulary flashcards covering bovine reproductive health, infectious cattle diseases, mastitis and milk quality, small ruminant production and diseases, and commercial poultry production and pathology.

Freemartin

A sterile heifer born co-twin to a male ($> 90\%$ occurrence, chimeric XX/XY) whose female reproductive tract is androgenized, resulting in abnormal internal/external genitalia, an underdeveloped or absent uterus, and $95\%$ sterility.

Postpartum Anestrus

The failure of a dairy cow to resume ovulation and normal estrous cyclicity by $60\,\text{DIM}$ (affecting $10\text{--}20\%$ of cows), commonly associated with a $\text{BCS} < 3$ at calving, a postpartum BCS loss $> 0.5$, or transition disease.

Voluntary Waiting Period (VWP)

The management interval of approximately $50\,\text{DIM}$ following calving during which cows are not inseminated, allowing sufficient time for gross uterine involution ($21\,\text{d}$) and histologic repair ($40\,\text{d}$).

Placentome

The complete ruminant placental unit of exchange composed of the maternal caruncle interlocked with the fetal cotyledon.

Schistosomus reflexus

A severe congenital fetal malformation characterized by fatal ventral spinal reflection and exposed abdominal viscera, presenting as a cause of dystocia.

Retained Placenta (RP)

Failure to expel fetal membranes within normal physiological limits due to impaired immune function and failed placentome detachment, mediated by reduced neutrophil chemotaxis and killing capacity $7\text{--}14\,\text{days}$ prepartum.

Metritis (Cattle)

A systemic uterine infection occurring within $3\text{ to }10\,\text{DIM}$, characterized by fetid (foul-smelling) reddish-brown watery discharge reflecting infection with anaerobic pathogens, carrying a cost of approximately $\\text{\$}500$ per case.

Purulent Vaginal Discharge (PVD)

A localized bacterial infection of the uterus or cervix diagnosed using a Metricheck device at $\ge 30\text{--}35\,\text{DIM}$, frequently associated with Trueperella pyogenes and costing approximately $\\text{\$}200$ per case in lost milk and fertility.

Endometritis (Cattle)

Cytological inflammation of the endometrium diagnosed by brush cytology without necessary concurrent active bacterial infection, hypothesized to arise from dysregulation of postpartum inflammation.

Neospora caninum

An intracellular coccidian parasite with dogs as definitive hosts; produces lifelong subclinical maternal infection in cattle with $> 90\%$ vertical transmission, causing abortions between $4\text{ and }7\,\text{months}$ of gestation.

Epidemiological Triad

The traditional disease model illustrating that clinical illness emerges from the dynamic interplay between host susceptibility, pathogen pressure (agent), and environmental conditions.

Non-Cytopathic (NCP) BVDV

The biotype of Bovine Viral Diarrhea Virus that does not destroy cultured cells; it accounts for $95\%$ of field infections and is the sole biotype capable of crossing the placenta to produce persistently infected (PI) calves.

Persistently Infected (PI) BVD Calf

An animal infected in utero with non-cytopathic BVDV before $125\,\text{days}$ of gestation that develops specific immunotolerance, shedding massive quantities of virus throughout life.

Mucosal Disease

A fatal syndrome occurring exclusively in BVDV PI cattle when superinfected with a cytopathic strain homologous to their persistent NCP strain, producing oral erosions, intractable diarrhea, and near $100\%$ case fatality within $5\text{--}7\,\text{days}$.

Cerebellar Hypoplasia (BVDV)

A congenital central nervous system anomaly marked by an underdeveloped cerebellum resulting in ataxia and tremors, caused by in utero BVDV exposure between $100\text{ and }170\,\text{days}$ of gestation.

Salmonella Dublin

A host-adapted, zoonotic serotype of Salmonella in cattle that frequently presents with severe septicemia and respiratory disease rather than classic enteric signs, often persisting endemically within herds.

Mycobacterium avium subsp. paratuberculosis (MAP)

A slow-growing, thick-walled, acid-fast bacterium extraordinarily resistant to environmental degradation and heat that targets the ileum, causing Johne's disease (paratuberculosis).

Bottle Jaw

Submandibular intermandibular ventral edema in cattle caused by severe hypoproteinemia secondary to protein-losing granulomatous enteropathy in advanced Johne's disease.

Risk Assessment and Management Plan (RAMP)

A standardized biosecurity evaluation scored out of $300$ total points, administered by a veterinarian to identify critical pathways of fecal-oral transmission of Johne's disease across all management groups.

Clinical Mastitis

An intramammary inflammatory condition producing visibly abnormal milk (flakes, clots, watery secretion), categorized as mild (milk only), moderate (milk and udder swelling), or severe (systemic illness).

Subclinical Mastitis

Intramammary inflammation absent of gross visible milk abnormalities, defined by an elevated somatic cell count ($\text{SCC} \ge 200{,}000\,\text{cells/mL}$ or Linear Score $\ge 4$).

Linear Score (LS)

A logarithmic transformation of milk somatic cell count ($\text{LS} = \log_2(\text{SCC})$) that exhibits a linear relationship with lactation milk yield loss.

California Mastitis Test (CMT)

A rapid cow-side chemical test whose reagent detergent lyses somatic cell membranes to release cellular DNA, forming a viscous gel proportional to neutrophil concentration.

Internal Teat Sealant (ITS)

A non-antibiotic bismuth subnitrate paste infused into the teat cistern at dry-off that provides an inert physical barrier mimicking the keratin plug throughout the dry period.

Selective Dry Cow Therapy (SDCT)

The targeted administration of intramammary antimicrobials exclusively to cows or quarters diagnosed with active intramammary infection at dry-off, while uninfected quarters receive only internal teat sealant.

Streptococcus agalactiae

A highly contagious, obligate intramammary pathogen causing widespread subclinical mastitis and elevated bulk milk SCC, characterized by high sensitivity ($90\text{--}95\%$ cure rate) to penicillin.

Staphylococcus aureus (Mastitis)

A major contagious mastitis pathogen characterized by deep micro-abscess formation, intracellular macrophage survival, fibrous scarring of the udder, and poor response to antibiotic treatment.

Coliform Mastitis

An acute environmental mastitis caused by Gram-negative bacteria (Escherichia coli, Klebsiella) from bedding or manure, where cell wall endotoxin release can induce severe endotoxemia within $12\text{ to }24\,\text{hours}$.

Seasonally Polyestrous

The reproductive pattern of sheep and goats where repetitive estrous cycles occur only in response to decreasing daylight hours during autumn and early winter (short-day breeders).

Ram Effect

The induction and synchronization of ovulatory estrus in transition-season ewes provoked by the sudden introduction of a novel intact ram after a minimum period of isolation.

Photoperiod Manipulation (Goats)

An environmental management technique exposing dairy does to $16\,\text{hours}$ of light followed by $8\,\text{hours}$ of light to mimic autumn day length, successfully inducing out-of-season estrus for winter milk production.

Enzootic Abortion of Ewes (EAE)

A highly contagious reproductive disease caused by Chlamydophila abortus, precipitating late-term abortion storms ($10\text{--}50\%$) in small ruminants and carrying significant zoonotic potential.

Tail Docking Length (Sheep)

The anatomical threshold for docking neonatal lamb tails (at $24\,\text{hours to }7\,\text{days}$ of age) situated at the distal boundary of the caudal tail fold, balancing thermal coverage and cleanliness of the escutcheon.

Iodine Deficiency Goiter

Thyroid gland enlargement in aborted or stillborn lambs and kids caused by maternal dietary iodine deficiency during gestation, endemic to regions such as the Great Lakes basin.

Hypothermia-Hypoglycemia Complex

The primary cause of mortality in neonatal lambs and kids during the first week of life, resulting from cold stress, starvation, and the rapid depletion of finite brown fat reserves (rectal temperature $< 37^\circ\text{C}$).

Pulpy Kidney Disease

An acute, fatal enterotoxemia in small ruminants caused by the proliferation of Clostridium perfringens type D and systemic epsilon toxin absorption, classically triggered by excess soluble dietary carbohydrates.

White Muscle Disease

Nutritional muscular dystrophy of skeletal and cardiac muscle in rapidly growing lambs and kids resulting from dietary deficiencies in selenium and/or vitamin E.

Footrot (Sheep)

A severe contagious hoof infection resulting from the synergistic interaction of environmental Fusobacterium necrophorum and Dichelobacter nodosus, leading to detachment of the hoof horn from the sensitive laminae.

Haemonchus contortus

The abomasal 'barber pole worm' of small ruminants that feeds aggressively on host erythrocytes, causing severe regenerative anemia, hypoproteinemia ('bottle jaw'), and death without accompanying diarrhea.

Small Ruminant Lentiviruses (SRLV)

A group of persistent retroviruses comprising Maedi Visna virus in sheep and Caprine Arthritis Encephalitis (CAE) virus in goats, causing progressive chronic interstitial pneumonia, arthritis, indurative mastitis, and wasting.

Caseous Lymphadenitis (CL)

A chronic, suppurative bacterial disease of sheep and goats caused by Corynebacterium pseudotuberculosis, presenting with encapsulated laminated ('onion-ring') abscesses in superficial and internal lymph nodes.

Scrapie

A fatal, federally reportable transmissible spongiform encephalopathy (TSE) of sheep and goats involving progressive central nervous system accumulation of abnormal prion protein ($\text{PrP}^{\text{Sc}}$), with susceptibility strongly linked to codon 171 polymorphisms.

Supply Management

A Canadian federal-provincial system regulating domestic production, pricing, and imports of chicken, turkey, eggs, and dairy under the Farm Products Agencies Act, utilizing production quota, import tariffs, and cost-of-production pricing.

Controlled Access Zone (CAZ)

The outer biosecurity perimeter of a poultry facility encompassing the working farmyard and barns, entered exclusively through dedicated, securable Controlled Access Points.

Restricted Access Zone (RAZ)

The innermost, highly secure biosecurity zone within the CAZ (specifically the poultry housing compartments) requiring complete boot changes, hand sanitization, and protective clothing.

Down-Time (Poultry)

The vacancy interval between flock depopulation and the placement of new chicks, maintained at $14\,\text{days}$ (or reduced to $7\text{--}10\,\text{days}$ following full cleaning and disinfection) to reduce environmental pathogen loads.

In-Ovo Vaccination

The automated administration of biologicals (such as Marek's disease vaccine) directly through the eggshell into the amniotic cavity of 18-day-old embryonated chicken eggs during transfer from setter to hatcher.

Cage Layer Fatigue

A metabolic bone disorder of caged laying hens during peak production caused by calcium, phosphorus, or vitamin $D_3$ exhaustion, causing severe medullary and cortical osteoporosis, vertebral collapse, and posterior paralysis.

Eimeria tenella

The protozoal agent responsible for caecal coccidiosis in chickens, destroying the lining of the caeca during the second schizont phase to produce severe hemorrhage, bloody droppings, and high mortality.

Necrotic Enteritis (NE)

A severe enteric clostridial disease of broiler chickens ($2\text{--}5\,\text{weeks}$ of age) caused by pore-forming toxins (NetB, alpha-toxin) of Clostridium perfringens, manifesting as enterocyte necrosis and a yellow pseudo-membrane ('Turkish towel').

Infectious Bronchitis Virus (IBV)

A highly contagious avian coronavirus causing acute upper respiratory signs (sneezing, gasping, rales), severe nephritis in nephropathogenic strains, and dramatic drops in egg production with watery, misshapen eggs.

False Layer Syndrome

Permanent reproductive tract dysfunction occurring when pullets under $2\,\text{weeks}$ of age contract IBV, causing irreversible cystic degeneration of the oviduct that prevents egg formation despite active ovarian ovulation.

Newcastle Disease (Velogenic)

A federally reportable, highly virulent avian paramyxovirus type 1 infection in poultry causing high mortality with acute respiratory distress, torticollis, and visceral hemorrhage, carrying zoonotic potential to cause human conjunctivitis.

Highly Pathogenic Avian Influenza (HPAI)

A federally reportable type A orthomyxovirus of poultry with wild waterfowl reservoirs, producing acute systemic hemorrhage, cyanosis of the comb and wattles, severe respiratory failure, and mortality approaching $100\%$.