Lab Animal Handling
General Principles for animal handling
Injections and Blood Collection
Blood sampling and foreign article administration is the common procedure that is performed regularly on all species, whether for diagnostic purposes or as part of the research.
Injections (Administration volumes)
For non-aqueous injection, consideration must be given to the time of absorption before re- dosing.
No more than two I/M sites should be used per day.
S/C sites should be limited to two to three sites per day.
Table 1 lists the recommended max. volumes that are considered as good practice for the commonly used routes in different lab species.
Blood collection
In all sps, total blood volume is approx. 6%–8% of total body weight, so, to be safe, we can assume that 6% of body weight = blood.
Safe acute sampling
Acute blood sampling is the one-time removal of a large volume of blood or multiple small samples of blood over a short period of time (24 h).
Chronic sampling
Chronic blood sampling is the frequent and repeated removal of small quantities of blood over a long period of time.
10%–15% of circulating blood volume may be removed once every 3 weeks. 1% of body weight can be collected every 3 weeks. |
6 mL of blood per 100 g 60 mL per blood per kg |
For chronic sampling, the rule of thumb is 0.1% of body weight every day for 21 days (e.g. a 30-g mouse can have 0.03 mL of blood collected every day for 21 days). The total volume of blood collected by chronic sampling is higher than acute, as the body continuously produces blood to replace that taken. |
Blood collection sites and volumes
Table 2 Recommended sites for blood sampling.
Table 3 Total blood volumes and recommended maximum blood sample volumes for species of given body weight.
Mice (Mus musculus)
Mice should be picked up by the base of the tail, close to the body.
Pregnant animals and young animals (preweaning) may need to be scooped up with one or both hands.
Weaner mice may be picked up by the tail, and care should be taken as they are usually very lively
Mouse handling and sexing
1. Grasp the mouse near the base of its tail [Fig. A.3(a)].
2. Lift the animal out of the cage and place it in new caging or on a firm surface.
3. Do not suspend the mouse by its tail for a prolonged period of time. Support its body weight quickly, especially for pregnant animals.
4. Check the sex of the animal [Fig. A.3(b)].
Fig. A.3 Mouse handling and sexing. (a) Removal from the cage and transport. (b) Identification of the sex of the animal.
Female mouse: genital area much closer to the anus. The urethra is usually within 1⁄4 inch (0.6 cm) on an adult mouse.
Female: vaginal orifice behind the urethra which may appear to look like a bump and Spot nipples with good lighting (as early as three days after birth)
Male mouse: genital area much farther away from the anus than in females and visible dropped testicles.
Scruffing
2. Ensure that enough skin is gathered to prevent the head from turning, while allowing the animal to breathe normally.
3. Place the tail between ring and little fingers to secure and control the animal.
4. The tail can also be held against the palm of the hand.
Mechanical restraint (plastic restrainer)
1. Grasp the nape of its neck.
2. Place its tail between your fingers to secure and control the animal.
3. Place the mouse’s head into the opening of the restraint box.
4. Release the hold on its neck while maintaining the grasp on its tail.
5. Place the securing block in the appropriate slot for necessary restraint.
Ear punching for identification
2. Place an ear punch in the desired location [Fig. A.6(a)].
3. Firmly and quickly punch its ear to avoid an incomplete cut.
4. Occasionally, the piece of tissue removed will be attached to the ear. This can usually be removed with the help of a pair of forceps.
Gavaging of mouse
1. Select correct-sized needle [Fig. A.10(a)].
2. Measure the needle length against the mouse’s body; should be no longer than from the nose to the last rib.
3. Fill the syringe.
4. Restrain the mouse by scruffing [Fig. A.10(b)].
5. Place the tip of the needle in the mouse’s mouth [Fig. A.10(c)].
6. Slide the tip down the back of the mouth, moving it toward the front in one fluid motion.
7. Once the needle is properly placed [Fig. A.10(d)], administer the injection article.
Rats (Rattus norvegicus)
Physiologic parameters Body temperature = 35.9°C–37.5°C Heart rate = 250–450/min Respiratory rate = 70–115/min |
Guinea Pigs (Cavia porcellus)
Guinea pigs have a mild disposition and are generally easy to handle.
Care must be taken when approaching guinea pigs, as they are nervous animals and are easily startled.
Approach them slowly and gently, and try not to make sudden movements or loud noises.
Guinea pig handling and sexing
2. Grasp the guinea pig around the thorax, placing its hind leg between index and middle finger for added support (Fig. A.25).
3. Check the sex of the guinea pigs by applying gentle pressure above the genitalia.
4.The penis of the male will protrude, making sexing easier (Fig. A.25).
FEMALE
The sows usually have a smooth swelling over their genital area. If one gently pat the genital opening, on a sow, a "Y" shaped opening will appear.
MALE�Slight pressure applied to get penis to extrude.
Female, 3 weeks old
Male, 3 weeks old
Guinea pig restraint technique for technical manipulation
Guinea pigs are quite docile animals.
Restraint by placing the animal on a table top and supporting it with one hand at the head and the other hand around the rump.
An assistant hold the guinea pig in place whilst the other person performs the procedures.
Alternatively, the guinea pig can be anaesthetised.
Rectal temperature:- 38.7 C-39.1 C
Normal respiratory rate:- 55/min
Pulse rate:- 135/min
Gestation period:- 28-31 days
Weaning age:- 6-8 weeks
Mating age:- 6-9 months
Litters:- 4 yearly ; average 4 litter
Room temp:- 15.5-18.5
Humidity:- 40 -45 percent
Weight – adult:- 0.9-6.75 kg
Tidal volume = 4–6 mL/kg
Self-mutilation has been reported in rabbits after IM ketamine administration.
Rabbits (Oryctolagus cuniculus)
Rabbit handling and sexing
1. Grasp the rabbit firmly by the nape of its neck. Place one hand on the rump of the rabbit and lift it from the cage.
2. Support its hind legs with the opposite hand. Tuck its head between its arm and body.
3. Check the sex of the rabbit by applying gentle pressure above the genitalia. The penis of the male will protrude, making sexing easier [Fig. A.28(b)].
The protruding circle: boy bunny
The flatter slit is the girl bunny
Rabbit restraint technique for technical manipulation
2. Place the rabbit in the centre of the towel and fold from one side, ensuring that the rabbit’s head and ears are not covered, but the feet and body are.
Nonhuman Primates (NHPs)
Many problems are encountered while handling &restraining (NHPs).
The use of proper restraint devices and techniques allows safe handling of these animals, and minimises stress and alterations in their physiological parameters.
Always ask for help in handling/restraining the animals and ensure the use of aseptic techniques for procedures.
Physiologic parameters Macaque Body temperature = 37°C–39°C Heart rate = 120–180/min Respiratory rate = 32–50/min Tidal volume = 21 mL |
zoonotic diseases- may be fatal in humans
The use of proper personal protective equipment (PPE) will help reduce zoonotic and physical trauma risks.
PPE- Disposable latex, nitrile gloves (double), Scrubs, Gown (long-sleeved), Properly fitting face mask (N95), Face shield, Nonslippery closed-toe shoes with shoe covers and Hair cover.
Always keep in mind that NHPs are quite aggressive animals; therefore, chemical restraint (ketamine) is generally preferred over physical restraint.
The blood volumes of NHPs vary but are generally around 8% of body weight. The maximum safe volume for a single collection is 6–10 mL/kg.
Common blood collection sites in NHPs include the cephalic, jugular, saphenous, and femoral veins.
NHP physical restraint
Physical restraint should only be attempted by trained, experienced personnel, and it should be both effective and as gentle as possible.
Various restraint devices used for NHPs include cages, nets, chutes and transfer boxes, stocks and restraint tubes, pole and collars, restraint chairs, etc.
For frequent handling, animals may be pole-and-collar trained; for frequent blood collection, tether systems are recommended.
NHPs can be temporarily restrained in a squeeze-back cage to facilitate veinpuncture, injection, topical application of drugs, close-up examination, capture, and other procedures.
Identification methods
Tattoo
the most common method of identification, but there is a risk of fading, so periodic renewal may be required.
Microchip
Microchip identification is probably the best available method for permanent identification of NHPs.
Microchips are permanent and tamper-proof, but are costly to use.
But ….
alternatives
REPLACEMENT
reduction
REFINEMENT
ETHICAL REQUIREMENTS
…. Thank You ….