ALAT Animal Husbandry and Care 4 — Questions and Answers
Question 1: Which of the following best describes the purpose of sentinel animals in a rodent colony?
- To act as dominant animals that maintain social order
- To serve as health monitors by detecting pathogens circulating in the colony (Correct answer)
- To be used as the first animals in new experiments
- To provide blood for transfusions to sick colony members
Correct answer: To serve as health monitors by detecting pathogens circulating in the colony
Sentinel animals are exposed to used bedding from colony cages and then tested periodically to detect subclinical infections in the colony.
Question 2: A technician is assigned to clean and disinfect rabbit caging. Which step must occur BEFORE disinfection is effective?
- Application of disinfectant at full concentration
- Thorough physical cleaning to remove organic matter (Correct answer)
- Rinsing cages with hot water only
- UV light exposure for 30 minutes
Correct answer: Thorough physical cleaning to remove organic matter
Organic matter (feces, urine, fur) inactivates most disinfectants; thorough cleaning must precede any disinfection step.
Question 3: What is the recommended light cycle for most standard laboratory rodent housing?
- 24 hours light, 0 hours dark
- 12 hours light, 12 hours dark (Correct answer)
- 8 hours light, 16 hours dark
- 16 hours light, 8 hours dark
Correct answer: 12 hours light, 12 hours dark
A 12:12 light/dark cycle is standard for most laboratory rodents to maintain normal circadian rhythms.
Question 4: A technician notices that a rat's fur appears yellow and oily. This condition is known as:
- Chromodacryorrhea
- Chromohidirosis (yellow fur syndrome) (Correct answer)
- Alopecia
- Porphyrin staining
Correct answer: Chromohidirosis (yellow fur syndrome)
Yellow fur syndrome (chromohidrosis) in rats is caused by secretion of yellow/orange pigmented compounds from the Harderian gland onto the fur.
Question 5: What minimum floor space (sq in) per mouse is required for animals weighing up to 25 g, according to the Guide for Care and Use?
- 6 sq in (Correct answer)
- 12 sq in
- 15 sq in
- 3 sq in
Correct answer: 6 sq in
The Guide recommends at least 6 square inches of floor space per mouse weighing up to 25 grams.
Question 6: Which of the following is the primary reason cedar shavings are NOT recommended as rodent bedding?
- They are too expensive for large colonies
- Aromatic hydrocarbons induce liver enzymes and can alter drug metabolism (Correct answer)
- They cause excessive dust that clogs water bottles
- They are too absorbent and cause cage flooding
Correct answer: Aromatic hydrocarbons induce liver enzymes and can alter drug metabolism
Cedar shavings emit volatile aromatic hydrocarbons that induce hepatic microsomal enzymes, confounding pharmacological and toxicological studies.
Question 7: During a health check, a technician observes red-stained tears and nasal discharge in a rat. This secretion is called:
- Hemolymph
- Chromodacryorrhea (porphyrin secretion) (Correct answer)
- Sanguineous rhinitis
- Conjunctival bleeding
Correct answer: Chromodacryorrhea (porphyrin secretion)
Chromodacryorrhea is the reddish-brown porphyrin-containing secretion from the Harderian gland, which appears around eyes and nares during stress or illness.
ALAT Animal Husbandry and Care 4
Which of the following best describes the purpose of sentinel animals in a rodent colony?