GUINEA PIGS

GUINEA PIGS

Pornchai Sanyathitiseree

Dept. of medicine

Introduction
Reproductive
Behaviour
Handling and restraint
Factors predisposing to disease
Foods
Housing
Disease

GUINEA PIGS ( Cavia porcellus )

Order Rodentia

Suborder Hystricomorpha

Three main breeds ;

English/Common short , straight , fine hair

Abyssinian rough , wiry hair in rosettes or whorls

Perruvian long , straight , silky hair

Dutch guinea pig are smooth-coated with white cheeks and a white blaze and white forequarters and the rest of the head are either red , black , chocolate , cream , golden , silver or agouti.

A guinea pig is commonly known as a cavy. They have stocky bodies , delicate short limbs , rounded hairless pinnae and no tail. They are more closely related to porcupines and chinchillas than to mice and rats. Their tranquil nature , relatively low cost and ease of maintenance make guinea pigs excellent pigs.

They seldom bite or scratch , respond pleasantly to regular handling and can be conditioned to squeal before such reward situations as the owner approaching the cage.

Guinea pigs have no laryngeal ventricle and their vocal cord are small.

All teeth are open rooted and grow continuously throughout life. The incisors are normally white , unlike those of many other rodents.

Adult male(boar) may weight over	1000 grams
Female(sow) usually weight about	850 grams
Food consumption	6 g/100g/day
Water consumption	10 ml/100g/day
Average life span	4 - 8 years
Peak reproductive time for female	3 - 4 mo. to 20 mo. Pet reproduce until 4 - 5 years of age
Sexual maturity	male 3 months female 2 months
Puberty ( male )	9 - 10 weeks
Puberty ( female )	6 weeks
Estrous cycle	15 - 17 days
Gestation period	59 - 72 days ( ave = 68 ) larger litter , shorter duration
Post partum estrus	fertile , 60 - 80 % pregnancy
Average litter size	3 - 4
Normal birth weight	70 - 100 grams
Weaning age	21 days or at 180 g body weight
Rectal temperature	101.5 - 103 F
RR	70 - 130 / min.
HR	230 - 300 bpm
WBC	5000 - 15000 / mcl
Average blood volume	70 ml/kg

Reproductive

After copulation there is a plug in the vagina formed by coagulation of the ejaculate. One or two days after copulation this plug falls out of the vagina.

In guinea pigs , unlike other rodents , anogenital distance is not an accurate method of determining sex. Instead , the guinea pig should be restrained and the shape of the external genitalia examined.

Determining the gender of guinea pigs is easily performed after the first day of life. The females have a Y-shaped anogenital area and the male it is slit-shaped. In males the os penis is palpable. The vagina is closed by a membrane except during estrus and at the time of parturition.

Pregnancy can be detected beginning on the 16 th day after breeding( ampullae have diameter of 1 cm. and can be palpated). After 23 days the diameter of the fetus is about 2 cm. After 30 th day of pregnancy in the guinea pig a torsion of the uterus can occur.

Females should first be bred between 3 and 7 months of age. After 7 months , the pelvic symphysis may be permanent fused; parturition may be difficult.

If the female is bred for the first time at age of 6 - 7 months , there are often problems. The symphysis widens less easily and fat can hider the passage through the pelvic canal.

Normal parturition is rapid , occuring typically with a few minutes between births. Guinea pigs do not built nests. Pups are normally delivered within a 30 minutes period with a resting period os approximately 5 minutes between pups.

The young are born fully haired and with eyes open.Young guinea pigs are able to run around directly after being born and can immediately eat hard food. The normal nursing periods of this species is 10 - 21 days , but young guinea pigs can also grow without nursing from the mother.

Behaviour

They are non-aggressive and they rarely bite or scratch.

Guinea pigs unlike hamsters and some other pets are sociable creatures and are usually all the happier for company , although they may ignore their humans more as a result.

Guinea pig are identical for children because they tend to be sweey tempered , pettable and relatively easy to catch if they escape from your child’s hand- mice , hamster , and gerbils , by contrast are able to hide for weeks or more if they escape.

If frightened, they may run around enclosure at a very fast speed , which makes one hard to catch.

Handling and restraint

Guinea pigs are easily frightened , make energetic attempts to escape being caught and often struggle and sequeal when handled.

They can be lifted by grasping the trunk with one hand while supporting the hindquarters with the other hand. A pig must be handled gently because the lungs can be injured if the animal is grasped too firmly onn the back. Support of the hindquarters is especially important when pregnant animals are being handled because it prevents struggling.

Factors predisposing to disease

Guinea pigs are ordinarily quite vigorous but are extremely susceptible to environmental factors that reduce resistance to infection. These factors include poor sanitation , overcrowding , improper temperature and humidity control and inadequate diet ( particularly insufficient vitamin C ). Even a simple change in the location of a cage can cause some weight loss.

Illness might not be immediately obvious to an untrained observer.

Do not house guinea pigs with animal species that carry Bordetella bacteria as a subclinical infection ( rabbits, cats , dogs ) as this may cause severe disease in cavies

The guinea pigs appear to be particularly susceptible to anaphylaxis with marked respiratory distress

Clients should be made aware of the potential of reaction prior to any injection.

Foods

During the first few days of life the guinea pig learns to discriminate between what is food and what is not. For this reason , changes in food later in life can lead to anorexia because the new food is not recognized.

A guinea pig’s main diet should consist of dried timothy hay (or another grass hay ) , supplemented by pellets and fresh vegetables. If grass hay is not feasible , a legume hay such as alfalfa may be substituted, although that should be avoided if possible because too much calcium can cause bladder stones.

Commercial guinea pig feed with 20% crude protein and 16% fiber is recommend.

Use only plain kind of guinea pig pellets (without nuts and dried fruit , which are high in fat and not good for your guinea pig)

Grass , carrot , and tomato --> all useful food. It is a source of vitamin C .

It is unable to synthesize its own vitamin C as it lacks the enzyme L- gulonolactone oxidase which is require to convert L- gulonolactone to L- ascorbic acid.

10 mg/kg
20 mg/kg ---> during pregnancy

The daily requirements for this vitamin will be met as long as a balanced diet of dry food,carrots and greens is fed. The vitamin C content of dried food will deteriorate over 9 - 12 weeks , so deficiency problems will arise if the dry food is stale.

It require a dietary source of supplemetal vitamin C add 50 mg cup drinking water or 200 mg vitamin C per liter ( If the water is not dechlorinated, it will inactivate the vitamin C ) and include one or more high vitamin C - containing food daily; 1/4 orange or small handful cabbage

Limit treat to no more than 1 - 2 tablespoon/24 - hour period : small amount green vegetables , carrot tops , apple , alfalfa cubes.

If you are not giving them the appropriate amount of the high vitamin C food , below on a daily basis , you will need to give vitamin C supplement. Crushed chewable C vitamins dissolved in the water works well for this.

The following chart shows the vitamin C content in milligrams (mg.) of 1 cup portions of selected food.

	Vitamin C (mg.)
Turnip Greens	260
Mustard Greens	252
Dandelion Greens	200
Kale	192
Brussels sprouts	173
Parsley	140
Collard Green	140
Guavas	125
Beef Greens	100
Cauliflower	100
Kohlrabi	100
Strawberries	100
Broccoli leaf	120
Broccoli Flortets	87
Spinach	60
Rasberries	60
Rutabaga	52
Orange	v
Cabbage(all leave and Chinese cabbage also)	50

Broccoli stem has 0 mg. Of vitamin C

Notice that oranges have less vitamin C than dark leafy greens.

Food values of cultivated crops

Broccoli contains vitamins A and B 2 , folic acid and vitamin C
Cabbage contain vitamin A and B6 , folic acid ,and vitamin C It also contains calcium , iron , copper and potassium.
Carrot contain calcium , iron , sodium and vitamin A,B1,B2,B6 and C
Clauliflower contain vitamin C , A and B1
Lettuce should only be fed in small amounts.It also contains the substance laudanum , which can be harmful.
Watercress this can be fed as a treat. It contains calcium , sodium , folic acid ,vitamin C and A

Food values of fruit

Apple They can be fed as a trteat but not given in large quantities as they are fairly acidic.

Rabbit food is also unsuitable as it does not contain adequate amount of vitamin C.

A balanced diet must include the following every day:

Concentrate - the dry food
Roots - carrot or beetroot
Green foods - cultivated or hedgerow plants
Hay - of good quality
Fresh water

As the guinea pig is always eating , a supply of hay must be constantly available to prevent boredom. Guinea pigs which have plenty of hay to eat are less likly to develop vices like hair chewing.

Cavie have sensitive intestinal tract; sudden alteration in diet ( including change in food brand ) may result in serious in GI upset and anorexia

Feed is usually supplied ad libitum in a hanging feeder.

Feed bowls should be cleaned regularly as a cavy may sit in them to defecate

Frequent defecate in floor - mount water bowls

Sipper tubes should be throughly cleaned daily (use large pipe cleaner) and water changed daily to avoid bacterial overgrowth in the bottle. An inverted bottle with a small siper tube justabove the bedding. Guinea pigs often mix food and water in their mouths and then pass the mixture back into the sipper tube , causing a green discolouration of the water that resembles the color of algae.

Rabbit feed looks like guinea pigs chow but is lower in protein and lack vitamin C. A guinea pid fed rabbit feed will demonstrate signs of vitamin C deficiency with in two weeks.

A pellet food with a guaranteed vitamin C, vitamin C content will be reduced with storage. ( no more than three month old from time to manufacture )

Keep diet in stable because they are fastidious feeders and may stop eating or suffer intestinal disturbance if the diet is change too quickly

Housing

Although guinea pigs are generally hardy , poor husbandry practices will lead to immediate deterioration in health.

Any kind of cage with a solid buttom (not wire) is okay. As for size , a rule of thumb is a minimum of two square feet per guinea pig. If they are not allowed to run around the room for exercise on a more or less daily basis , they will need a lot of more space to be happy and healthy.

Since guinea pigs do not jump very high , you do not need very tall sides for whatever housing you provide. Guinea pigs are not apt to climb and thus can be kept in open top cages with side at least 10 inches high.

Bedding should be provided in abundance : hardwood shavings , composite recycled paper materials , pellets , shredded paper.

If a young guinea pig must be put on mesh flooring , a piece of cardboard placed on the floor will ease the transition from a solid floor. By the time the animal has chewed up the cardboard and grown larger , it will have learned to walk safely on wire.

Bedding must be changed frequently to prevent fecal material and urine moisture build up.

Hidding box is appreciated for sleeping or retreat if startled.

Room temperature should be maintained between 65 and 75 F and the cage should not be placed in direct sunlight.

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