Bovine Herd Health Flashcards
7 cards from real NAVLE practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Bovine Herd Health flashcards as text
A dairy herd manager asks about dry cow therapy. Which approach describes selective dry cow therapy (SDCT)?
Answer: Treating only cows with elevated SCC or positive culture at dry-off
Selective dry cow therapy targets only cows with evidence of intramammary infection, reducing antibiotic use compared to blanket dry cow therapy.
Calf scours causing the highest mortality in calves under 5 days of age on a US beef operation is most commonly caused by which pathogen?
Answer: Escherichia coli (enterotoxigenic)
Enterotoxigenic E. coli (K99 fimbriae, F5 antigen) causes profuse watery diarrhea and rapid death in calves under 4 days old due to severe dehydration.
A producer wants to reduce the risk of hardware disease (traumatic reticuloperitonitis) in his dairy herd. What is the most cost-effective preventive measure?
Answer: Administering rumen magnets to all cows
A permanent ceramic or bar magnet placed in the reticulum captures ingested ferrous metal objects, preventing them from penetrating the reticulum wall.
Which internal parasite is responsible for 'ostertagiosis type II' (winter ostertagiosis) causing severe hypoproteinemia and diarrhea in yearling cattle?
Answer: Ostertagia ostertagi
Type II ostertagiosis occurs when inhibited L4 Ostertagia ostertagi larvae resume development in late winter/spring, massively emerging from gastric glands and causing profound hypoproteinemia.
A beef operation loses 3 cows to sudden death with no premonitory signs. Necropsy reveals a 'paint-brush' hemorrhage pattern on the heart and rapid bloat. Which clostridial disease is most likely?
Answer: Blackleg (Clostridium chauvoei)
Blackleg (C. chauvoei) classically affects young cattle 6–24 months, causing myonecrosis with rapid death and characteristic crepitant swellings and myocardial hemorrhage.
On a 500-cow dairy, the conception rate to first service drops from 42% to 28% over 3 months. Which herd-level factor should be investigated first?
Answer: Heat detection efficiency and estrus expression
In AI-based dairies, poor heat detection is the most common cause of declining first-service conception rates, as undetected or wrongly timed AI submissions drive down the metric.
What is the recommended colostrum management '1-2-3 rule' for newborn dairy calves?
Answer: 1 gallon within 2 hours of birth, immunoglobulin concentration ≥50 g/L (Brix ≥22%)
The 1-2-3 rule recommends 1 gallon (≈4 L) of high-quality colostrum (≥50 g/L IgG) fed within the first 2 hours after birth, with a Brix refractometer reading ≥22% confirming adequate quality.