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ASSIGNMENT ON

PRODUCTION, BREEDING AND MANAGEMENT

OF LABORATORY HAMSTER

Small Laboratory Animal – AGB 609 & 610

SUBMITTED TO

Dr. Amit kumar,

Agricultural Research Scientist,

Animal Genetics Division,

Indian Veterinary Research Institute, Izatnagar

SUBMITTED BY

Pavulraj.S,

Roll No: 5246,

M.V.Sc. Scholar,

Division of Veterinary Pathology,

Dr.pavulraj .S

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PRODUCTION, BREEDING AND MANAGEMENT OF

LABORATORY HAMSTER

Hamsters are rodents belonging to the subfamily Cricetinae. The subfamily contains about 25 species.

Hamsters are widely used in research.

In captivity, golden hamsters follow well-defined daily routines of wheel-running activity, which has made them popular subjects in circadian rhythms research. They have a number of fixed action patterns that are readily observed, including scent-marking and body grooming, which is of interest in ethology - the study of animal behavior.

The greatest use of hamsters is in biomedical research. Because captive golden hamsters are highly inbred (being descended from only a few captured individuals), they have a high incidence of a genetic heart condition causing dilated cardiomyopathy. Several inbred strains of hamsters have been developed as animal models for human forms of dilated cardiomyopathy.

Syrian hamsters are also widely-used in research into alcoholism, by virtue of their large livers, and ability to metabolize high doses.

Common experimental models

Diabetes mellitus

Cholelithiasis

Periodontal disease

Myocardial degeneration

Lung diseases including emphysema

Dental caries

Foreign tissue transplantation

Radiobiology research

Parasitology research- Entamoeba spp and Leishmania spp.,

Viral Research-slow virus(Scrapie,chronic measles,etc),type C Onco virus,influenza virus, respiratory syncytial virus studies and vaccine production

Used for in vivo and in vitro diagnostic techniques for numerous infectiousagents - Clostridium spp., Leptospirosis spp.,

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Hypothermia research - When the hamster hibernates, the body temperatureand other physiological parameters, such as heart rate, activity decreasesubstantially. This makes it easy to study long term effects of hypothermia.

Taxonomy

Order: Rodentia

Suborder: Myomorpha

Family: Cricetidae

Genus :

Mesocricetus auratus- Syrian or golden hamster-commonly used in biomedical research

Cricetulus griseus - Chinese hamster - used in biomedical research

Cricetus cricetus - European hamster

Phodopus sungorus - Djungarian (or dwarf) hamster

Cricetulus triton - Korean gray hamster

Cricetulus migratorius - Armenian (or gray) hamster

General characteristics of hamster

1. Have cheek pouches. Used for storing feed, bedding or nesting material and to hide

neonates when mother is frightened. These pouches are devoid of glands and lymphatic

vessels. They readily accept foreign tissue grafts or transplants. So called as

immunologically privileged site.

2. Have thick bodies and short tail.

3. Newborn has teeth.

4. Have sebaceous glands (or scent glands, or flank glands, or hip glands) are located on

left and right dorso-lateral flanks. They are black in color, more prominent in male and

rudimentary in female.

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5. Have never been produced by caesarean derivation of foster-nursing on other germ-

free species.

6. Docile unless surprised or awaken.

7. Nocturnal

8. Hibernate when temperature drops below 5o C, but animal is responsive to external

stimuli.

9. Curious by nature

Biology of Syrian Hamster (Mesocricetus auratus)

Life Span: Body Length: Tail Length: Adult Weight:

Number of Mammary gland: Litter Size: Weaning Age: Estrus Cycle: Duration of Estrus Cycle: Duration of Estrus: Gestation Period:

Puberty: Female Breeding Life: Male Breeding Life: Rectal Temperature:

Blood volume: Heart rate: Respiratory rate: Daily food consumption: Daily water consumption: Urine:

2-3 years, record 4 years 170-180 mm 12 mm 90-175 gm.Often female is larger than the male. 12-16 (22 may occur) 6 or 7 (4-15) about 3 weeks Poly-estrus- all year 4-5 days 4-23 hours 15-18 days (average 15 1/2 days) 8-10 weeks about 1 year 1 year 97.0oF to 102.3o F, average 99.3o F (36.10 C to 38.9o C, average 37.4o C) 7.5% of body weight 275-425 beats/minute 33-l27/minute (average 74) l0-14 gms 7-l0 mL Crystalluria, cream-colored, turbid, pH 8.0

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Feces:

Milk composition:

Chromosome number:

Dental formula:

Almost black, tubular, firm, about 5 mm long 74% water, 12.6% fat, 9% protein, 3.4% sugar 2n = 44

I l/l, C 0/0, PM 0/0, M 3/3 = 16

Management

1. Housing

a. Caging1. Plastic shoebox solid bottoms lid to prevent escape.

2. Space requirements(a) Hamster < 60gm - 10sq.in.(b) Hamster > 60gm – 11-20sq.in.(c) Female with litter - 150sq.in.

Plastic cage

Hamsters are aggressive and territorial. Individual housing after weaning at 21 to 28 days of age will prevent morbidity from fight wounds and subsequent infections. If same sex groups are housed together after weaning, they must be observed frequently for bite wounds and abscesses.

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b. Beddingo Routine types include: hardwood chips, sawdust, shavings, corn cobs,

and beet pulp.o Pregnant animals will use soft paper for nest building.o Bedding should be replaced 1 or 2 times weekly and can be left as long as

2 weeks when is desirable to leave a litter undisturbed.

There are many different types of bedding materials that can be used to line the bottom of cages. Traditionally Wood Shavings (or Sawdust) is used, though there are alternatives to this which can be a big help to anyone with an allergy to them.

The substrate needs to be at least 3cm deep over the base of the cage, this is so it will absorb hamster’s urine and provide stimulation for the hamster of digging into it.

Substrate Pros Cons

Wood Shavings Cheep, widely

available, reasonably absorbent

can get tangled in Long hair, can sometimes not absorb smells well

Sawdust Will not tangle in

coat, very absorbent some fear issues with the dust in

eyes/nose,

wood based cat litter widely available, does

not tangle in coat, can become dusty quickly, often not too

absorbent, not as soft as alternatives

wood pulp beddings (e.g. carefresh/megazorb)

very absorbent, does not tend to tangle,

very soft

can be expensive or hard to find, can sometimes tangle in long hairs

Hemp beddings (e.g. Aubiose)

does not tend to tangle, reasonably

absorbent,

Can be hard to find, will occasional still tangle in long hair.

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Cardboard bedding (e.g.Finacard)

Does not tangle in coats

can be hard to find, tends not to absorb smells well, often does not absorb well, has

been known to have bits of tape etc in it

c. Temperature/Relative Humidity Adults should be maintained at approximately 65 to 70 degrees F with 40-60% relative

humidity. Breeding rooms should be kept slightly warmer (71-75o F). Hamsters are more adaptable to cold extremes than to warm extremes.

d. Photoperiod12-14 hour light period daily with 14 hours required for breeding colonies.

2. Feeding

Nutritional requirements Since the hamster's first stage of digestion is a fermentation process their nutrient utilization is slightly different than that of other rodents. Often times rat feed is used as a basic diet and is then supplemented with rabbit chow or other similar diets.

Soybean meal provides a better protein supplement than fishmeal at about 16% of theration. Protein levels of 18-24% promote more rapid growth, but at the cost of higherincidences of nephritis.

More complex carbohydrates, such as, corn starch are more highly tolerated energsources. 30-40% corn starch in the ration is ideal

Compared to the rat, the hamster has a higher requirement for zinc, copper, andpotassium.

Feed delivery If food hoppers are used, the feed pellets must be able to fall through the slots to the

floor of the cage. This is required because the hamster's muzzle is as broad as they would be forced to chew food from both sides of the metal strips of the feeder resulting in broken teeth and starvation.

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Water A continuous supply of fresh clean water is required. Water delivered via Stainless steel

siper tubes is most desirable. Water should be available to young hamsters when they begin to consume dry food. This is usually at 7 to 10 days of age. If water bottles are used, the sipper tube needs to be placed 1/2 to 3/4 inch above the bedding, until after the pups are weaned at 21 to 28 days of age. An adult hamster will consume 5 ml of water per 100 g of body weight per day.

Sexing and breeding

Sexing

Sexual identification in hamsters is similar to other rodents - the ano-genital distance in the male is greater than in the female

Sexing pups

Sexing of hamster pups is somewhat more difficult, but the principle is the same - the animal with the longer ano-genital distance is the male. Also notice in this image, that the mammary glands are much more distinct in the female pup, on the left.

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Breeding of hamsters

A most important decision will be which male and female hamsters when put together are

• Age of hamsters• Health• Temperament• Color/Pattern and Fur

Not taking due regard to any of these issues can seriously affect production of a strong and healthy litter of pups.

Hamsters may become sexually mature as early as 4 to 6 weeks of age, although the usual age is 6 to 8 weeks. This precocious sexual development makes it important to separate litters by sex at weaning. Optimal age for initial breeding is 8 to 10 weeks for females and 10 to 12 weeks for males.

The age of a female hamster needs to be considered when thinking of breeding. An ideal age for a hamster’s first litter is between 5 and 6 months old. Should never mate a hamster earlier than three months old, as she may not be mature enough to cope with raising a litter and she will still be growing and maturing herself, may have her growth restricted by the strain of producing pups.

It is thought also that it can be dangerous for a female over the age of 6 months to have a first litter as some sources believe this can cause complications in giving birth. Females usually become sterile at about a year old.

The age of the male hamster is less important than that of the female. The hamster needs to be old enough to be large enough and able to breed. Older hamsters may be infertile and with a very old hamster, the act of mating can put quite a strain on his heart, so preferably the male should be a fit and mature young hamster.

Be aware of the general health of the prospective parents. They should exhibit no signs of illness or disease and should be large, fit and the picture of health.

Stage of cycle can be determined by the tenacity and opacity of vaginal discharges. The discharge is thick and opaque at the time of and after ovulation.

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Heat generally begins approximately 1-2 hours after dusk on the third day of the estrous cycle and ovulation is completed 6-10 hours after onset of psychic estrus. The female should be placed in the cage with the male at the beginning of the dark cycle.

If the female is receptive she will quickly assume a lordosis position with hind legs spread and tail erect. If copulation does not occur within 5 minutes or if the female becomes aggressive, she is removed. If copulation occurs, the pair can be left together until the following light cycle.

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Mating

1. Monogamous

Several mating systems are used successfully for Syrian hamsters. In the monogamous system, hamsters are hand-mated. The female is placed with a male 50 to 60 min prior to the start of the dark cycle, 3 days after the appearance of the vaginal discharge. If the female is receptive, lordosis and copulation ensue. It is important to observe the pair, because the female can be very aggressive if she is not receptive and may physically harm the male.

2. Polygamous

In polygamous or group-mating systems, 1 to 4 males and a greater number of females than males are housed together for 9 days or 2 estrous cycles. Group-housed hamsters must be frequently observed for fight wounds, and females checked daily for post-ovulatory discharge. If after 9 days there has been no discharge, the female hamster is assumed to be pregnant or pseudopregnant. Pregnant hamsters begin to gain weight by day 10 of gestation, and the abdomen appears distended. The gestation period of a hamster averages 16 days.

A copulation plug will be visible for a few hours after copulation. Colony raised females can be returned to the colony until day 14 of gestation if they don't fight. Pregnant animals should be separated and undisturbed for at least 2 days prior to and 7 day after parturition to avoid litter cannibolism.

Estrous cycle will not resume for the mother until a few days after her young are weaned. Young from different litters can usually be housed together until 50 days of age.

Care of pregnant hamsters

Hamsters have a very short gestation period of 16 days with pups being born usually between the evening of the 16th day and early on the 17th day.

During the post mating period it is important to supplement the female’s diet with extra

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nutrients. Feed the females a diet of her normal food along with extra protein such as chicken, scrambled egg, and porridge or rice pudding made with milk.

Continue extra foods to the mother right up to and past weaning the pups as raising a large litter requires a lot of energy.

There are very few signs of pregnancy before the 10th day after mating. At this stage can find that the hamster has visible bumps either side, looking like it has swallowed a ping pong ball. The nipples may also become more noticeable.

If you think your hamster is pregnant you must prepare for her to raise the litter. Her normal cage may not be appropriate, and you may wish to consider alternatives or making adjustments.

Cages with tubes are not ideal for a mother to raise her pups in, as, if she gives birth on a higher floor, the pups may fall down the tubes. Also consider in wire cages that pups may possibly be able to escape through the bars. We use tank style cages for our nursing mothers.

Parturition

Pregnant hamsters should be housed singly at least 2 days prior to parturition. This would be about day 12 to 14 of gestation. The main concern, whether in a monogamous or polygamous breeding arrangement, is not to leave the pregnant females with the males. Sufficient feed, water, and nesting material should be provided so that the dam and litter will not be disturbed for 7 to 10 days postpartum. Excessive noise and disturbance of the cage or litter may cause the dam to cannibalize her offspring, especially if she is primiparous.

Raising pups

Mother will give birth to the pups singly, and the whole process can be over quickly. When

born, hamster pups look nothing like the fluffy adults they will become, being small, pink and

totally naked. The eyes and ears will be sealed shut behind skin.

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The nest should be left undisturbed. Never be tempted to open the nest to just catch a

glimpse of the pups, it just is not worth the risk.

Make sure that the mother continues to be fed a high protein diet and is left in peace to be

able to tend to her pups needs.

Sound of squeaks from the nest produced as the pups settle down to feed. Sometimes can

hear the hum of the pups as they contentedly suckle.

A major note of warning if we see a pup outside of the nest, don’t be tempted to touch it.

Mother will usually return to collect the pup herself, but by touching the pup, may transfer our

smell onto it, risking the mother rejecting it and killing it and possibly even more pups.

If, after a long time, the pup is still out and looks too weak, then using some safe material,

such as a spoon or a piece of card rubbed well into mothers toilet corner, scoop up the pup and

return it to the nest.

After the first week mother leaves the nest uncovered, fur appearing on the pups. Can

able to distinguish light colors from dark and if the pups have any patterns like the banded

pattern this will be visible. The ears will have started to stand away from the head and the pups

should have lost that wrinkled look.

The pups will be starting to eat solid food. Mother will usually bring food back to the nest

but make sure there is plenty available for them, so from about six days onwards sprinkle small

particles of food and wheat-germ around the nest for them. At this stage also increase the

amount of food offering to include the pups.

During the second week pups will usually start to venture out of the nest. Make sure that

they can reach the water bottle. Can start to feed second stage baby food to the pups as well

from the first week onward in addition to the chicken, eggs, porridge and vegetables that have

been offering to mother at this stage.

Use a very shallow dish to allow the pups to easily reach the food such as a jam jar lid. This

also makes sure that they cannot fall into deeper bowls of food and possibly drown.

At about 14 days old the pups will begin to open their eyes and their fur will have grown

so that they look very much like mini-hamsters.

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From two weeks onwards the pups will continue to grow quickly.

From three weeks onwards the pups will be being weaned from mother.

Handling and identification

The hamster lacks a tail to assist in restraint, and hamsters are more aggressive than rats or mice. However, there are several ways to safely pick up and manipulate hamsters. This drawing depicts one method. The hamster is grasped around the head and shoulders, with the thumb directed toward the tail. It is important not to surprise or startle the hamster prior to handling, as it might bite.

1. One-hand grasp

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An effective method for firm restraint is to place the hamster on a flat surface and cover it with your palm with the thumb near the hamster's head. Slowly close the hand allowing the loose skin to bunch, as shown here. You will be grasping the skin, not the body of the hamster.

2. Picking up

Grasp the loose skin over the back firmly and lift the hamster. Its eyes may appear to bulge when the skin of the head and neck is grasped firmly, but this is not painful or dangerous. The hamster will now be securely held, with the skin taut over the abdomen and chest. This method of restraint is satisfactory for administering injections, lavage, or other manipulations.

3. Two-hand carry

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Identification

Individually housed hamsters can be identified by cage card, without physical marking of the animals. Ear notches or ear tags are effective identification, if group-housed, other hamsters may chew out the tags or marks. In the past, toe clipping under generalized anesthesia was used for identifying individual hamsters in small populations. But is generally discouraged as an undesirable method since there are adequate

alternatives. Currently, subcutaneously implanted microchip transponders with unique encoded numbers are being used in some facilities for animal identification.

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References

Guide for the care and use of laboratory animals - eighth edition

- Janet C. Garber

The Hamster Handbook

- Patricia Pope Bartlett

Veterinary laboratory manual - 9th edition, veterinary laboratory

service

http://exoticpets.about.com/od/hamsters/p/syrianhams.htm

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