The document discusses laboratory animals and their use in biomedical research. It states that rodents like mice and rats are most commonly used as they are inexpensive and easy to care for. Ideal laboratory animals must be bred and housed in rigorously controlled environments. Proper housing, management, sanitation and environmental conditions are required to ensure animal welfare and quality research data. Common laboratory animals include mice, rats, hamsters, guinea pigs and others. Rodent breeding procedures aim to provide offspring for research according to investigators' protocols.

1. By: Puja R. Bhalerao
M.Pharm

2.  Theoretically, any organism can be used as a laboratory model for
scientific investigations, but only few species are chosen to serve in
biomedical fields.
 These animal can serve as a model for a human being in all those
functions in which there is a considerable degree of genetic
similarity.
 An important requirement for laboratory animals (apart from price)
is that they should be easy to keep. Today, rodents meet this
demand best. Of all the mammals, mice and rats have been most
frequently used in laboratories.
 Environmental requirements will vary with the species and the
experimental protocol. In general, a constant and comfortable
environment is required to ensure both the health of the
experimental laboratory animal house for meaningful results.

3.  To be defined as laboratory animal, ‘’ The species must be
bred and raised under ideal conditions and kept in a
rigorously controlled environment under constant monitoring
so that all microbiologic and genetic factors are known.”

4.  Mouse
 Mice
 Rat
 Hamster
 Guinea pig
 Pig
 Dog
 Cat
 Monkeys

5.  Proper housing and good management of animal facilities are
essential for the animal well-being, the quality of the research data,
and the health and safety of the personnel.
 At a minimum, an animal must have sufficient space to turn around
and to express normal postural adjustments, it must have ready
access to food and water, and it must have enough clean bedded or
unobstructed area in which to move and rest.
 Whenever appropriate, social animals should be housed in pairs or
groups, rather than individually.
 Many laboratory animals, especially the smaller species, establish
their own microenvironment within their cages. The nature of these
will vary with the animal’s habits, the type cage and the climatic
conditions prevailing within the room itself.

6.  The person in charge of the establishment must ensure regular
inspection and maintenance of the animals .
 Wherever it is possible species should be housed in separate rooms.
Shipment of the same species, acquired from different suppliers,
should also be separate if space permits. Where the mixing of
species and/or stocks from different sources may be unavoidable
every effort should be made to placed together those that are
compatible, have similar environmental requirements .

7. 1. Food, drinking water and bedding:
 Feed:
Animals should be fed palatable, non contaminated and nutritionally
adequate food, daily or according to their particular requirements. .
Packing, transport and storage must be such as to avoid contamination,
deterioration or destruction.
The feed distribution process may vary according to the species,
but must be such as to satisfy the physiological needs of the animal.
 Drinking water:
Animals should have access to potable, uncontaminated
drinking water according to their particular requirements. (During transport,
it is acceptable to provide water as part of a moist diet.) Watering devices
should be checked daily to ensure their proper maintenance, cleanliness and
operation. The methods commonly used in watering involve bottles, dishes
and automatic systems.
 Bedding:
Bedding must be dry, absorbent, non dusty, non toxic and
free from infectious agents or vermin or any other form of
contamination. Special care must be taken to avoid sawdust or bedding
material derived from wood which has been treated chemically.

8. 2. Sanitation:
Sanitation (the maintenance of conditions conducive to
health) involves bedding changing (as appropriate), cleaning and
disinfection. Cleaning removes excessive amounts of dirt and debris, and
disinfection reduces or eliminates unacceptable concentrations of
microorganisms. The standard of a facility depends very much on good
hygiene. . All components of the animal facility, including animal rooms
and support areas, should be cleaned regularly . All cages, pens, racks
etc. must be thoroughly cleaned and disinfected before reuse. As a
general rule, the animal house should be cleaned every day or alternative
day. Animal cages are most efficiently cleaned and sanitized with
mechanical washing equipment operating at 83oC (180oF) or higher, for
a minimum of ten minutes.
3. Contact with the animals:
The performance of an animal during an experiment
depends very much on its confidence in man, something which has to be
developed. It is therefore recommended that frequent contact should be
maintained so that the animals become familiar with human presence
and activity . The staff must be sympathetic, gentle and firm when
associating with the animals.

9.  Temperature:
The temperature must be measured continuously. The
recommended (optimal) temperature range for mice, rats, guinea pigs
and miniature pigs is 20–24 C, while for dogs, cats and rabbits it is 15–
21 C. Sudden change in temperature variations may harm laboratory
animals. Emergency equipment to maintain appropriate environmental
temperatures should be available.
 Humidity:
Extreme variations in relative humidity (RH) have an adverse
effect on the health and well-being of animals. The RH must ordinarily be
maintained at 55+10%. Levels below 40% or above 70% for a prolonged
period must be avoided.
Fluctuations and extremes in relative humidity can
precipitate illness, particularly respiratory diseases.
 Ventilation:
The animal facility should be ventilated properly. It is
preferable to use a total air exchange system.
The purposes of ventilation are to supply adequate oxygen
(fresh air); to remove thermal loads caused by animal respiration, lights
and equipment; to dilute gaseous and particulate contaminants (e.g.
ammonia or dust); to adjust the moisture content of the room air.

11.  Genetics is the science of heredity and variation.
 All animals have a predetermined genotype that they inherit from their
parents. However, an animals genotype can be manipulated by breeding
and more advanced scientific techniques (genetic engineering and
cloning).
 Animal breeding is a segment of animal science that addresses the
evaluation of the genetic value of domestic livestock.
 A breed is a group of domestic animals with a homogeneous
appearance, behavior, and other characteristics that distinguish it from
other animals.
 Animal breeding is the process of selective mating of animals with
desirable genetic traits to maintain or enhance these traits in future
generation.

12.  To maintain breeding colonies according to the needs of
principal investigators .

13. Hand mating
Pair mating
Harem mating

14.  In this method male and female are brought together for a brief
period and then separated once the mating is over.
EX : Rabbits and Hamsters

15.  In this method male and females are mated together rest of their
breeding life.
 In this method in case of mice one male mated with one female , and
left together for the rest of their breeding life.
 in the case of rats , pregnant females should be isolated prior to
delivery.
EX : Rats and Mice

16.  In this method males and females are run together , but separated
prior to parturition .
 In this method four females are regularly mated with one male.
 The female is separated soon after the pregnancy is established, and
replaced by fresh females.
EX : guinea pig

17. Item Rat Mouse
Breeding age – male
female
100 day for both 50 days
50-60 days
Estrous cycle 5 days 4-5 days
Gestation 20-22 days 17-21 days
Weaning age 16-21 days 21 days
Litter size 12 8-12 days
Breeding life : male
female
1 year
1 year
18 months
7-9 months
Mating group 1.3-5 1.3-4

18.  The exact procedure for rodent breeding for investigators is
performed according to instructions in the individual animal use
protocols.
 The most important item on a rodent breeding bin is the cage
ID/breeding record card.
1. This card records the breeding of 1-2 female rodents per cage.
Breeding cage cards should be filled out completely.
2. Records of rodent breeding are also kept in a Breeding Book that is
kept in each room used for breeding.
 One male and 1-2 females are placed in the breeder cage. The pair
should be provided with a Shepard shack or hiding box and fed a
breeder diet. Females should be housed together in order to
synchronize their estrus cycle. The male is then introduced into the
females’ cage.

19.  When sufficient offspring have been produced, the male is removed and
placed back into a holding cage. Otherwise, the male can remain in the
cage with a single female. Alternatively, the male may be removed
before the litter is born to minimize the possibility of cannibalism.
 Females may be separated from males near parturition or they may be
permanently paired with a male.
 Juveniles are usually removed at 21 days, the average weaning age for
rodents, or longer depending on size.
 It is also important to identify individual breeding animals as closely as
possible and record their ages and breeding data. This can be
accomplished by grouping adult breeders and identifying the cage with a
regular cage I.D. card. At the investigator’s request, and according to
instructions written in their animal use protocol, other methods of
identification can be used (ear punching, ear tags, etc.).
 Animals that reach or exceed their breeding life should be culled from
the colony and replaced with offspring reserved for this purpose (It may
be necessary to periodically bring in “new blood,” i.e., new animals from
other blood lines in order to maintain the viability of the colony).