Dairy 6 Ultimate Study Guide

Mastitis

Inflammation of the mammary gland, predominantly caused by intramammary infection from bacterial pathogens.

Intramammary infection (IMI)

An infection within the mammary gland, often caused by bacteria, that leads to mastitis.

Clinical mastitis

Mastitis characterized by visibly abnormal milk, possibly accompanied by physical changes to the mammary gland.

Subclinical mastitis

Mastitis that is not apparent through visible symptoms but can be detected through somatic cell count (SCC) measurements.

Somatic Cell Count (SCC)

A measurement of the number of somatic cells in milk, used to indicate the health of the udder.

Bimodal distribution in infections

A pattern of new intramammary infections that peaks sharply during the first two weeks post-dry-off and again just prior to calving.

Blanket Dry Cow Therapy (BDCT)

Standard practice of infusing long-acting antimicrobials and internal teat sealants into every quarter of every cow at dry-off.

Selective Dry Cow Therapy (SDCT)

Administration of intramammary antibiotics solely to cows with verified infections, using internal teat sealants for uninfected quarters.

Epidemiological Triad

A model describing the interaction between host, agent, and environment in the context of disease occurrence.

Antimicrobial resistance

The ability of bacteria to withstand the effects of medications that once successfully treated them, complicating mastitis management.

Coliform mastitis

Mastitis caused by environmental bacteria such as Escherichia coli, leading to acute clinical cases.

Total bulk compliance threshold

The maximum limit for bulk tank milk somatic cell count, ideally less than 400,000 cells/mL to avoid penalties.

California Mastitis Test (CMT)

A rapid, qualitative screening assay at the quarter level used to detect subclinical mastitis.

Economic loss per case of clinical mastitis

Direct and indirect costs ranging from approximately $120 to $300 for each individual clinical case.

Host-immunity factors

Systemic immune function, nutritional adequacy, and anatomical integrity that affect the host's ability to resist infections.

Environmental mastitis

Mastitis caused by pathogens from the cow's environment, often linked to failure in sanitation and hygiene practices.

Contagious mastitis

Mastitis transmitted from cow to cow, often during milking, due to poor hygiene or care.

Pathogen load

The quantity of pathogens present, critical to determining whether an infection will occur.

Economic impact of mastitis

Mastitis is the most costly disease in the dairy industry; costs include lost production and increased veterinary care.

Dairy Herd Improvement (DHI) programs

Programs that monitor and analyze individual cow milk sampling for health and production metrics.

Endotoxemia

A condition resulting from the presence of endotoxins in the blood, particularly following infections such as coliform mastitis.

Milk production deficits

Loss of milk production attributable to both unharvested volumes and direct impacts of mastitis infections.

Pre-dipping and post-dipping

Hygiene protocols involving the disinfection of teats before and after milking to reduce infection risk.

Core-antigen mutant Gram-negative vaccines

Vaccines designed to reduce the severity of coliform mastitis and its resulting systemic inflammatory responses.

Nutritional management

Adjusting cows' diets prior to dry-off to help manage milk production and reduce mastitis risks.

Culling due to mastitis

The removal of cows from the herd due to chronic mastitis or udder health failures, ideally kept under 5 cases per 100 cows per year.