Animal Management: Reproduction in Rabbits and Rodents

Name 4 common pet rodent species

guinea pig, hamster, rat, mouse

Is a rabbit a rodent?

no

What is the main role of the vet in rabbit and rodent reproduction?

preventing reproduction

At what age to rabbits/rodents become capable of reproducing?

age of sexual maturity

What is the age of sexual maturity in a male rabbit?

4-6 months (or >8 in giant breeds)

What is the age of sexual maturity in male guinea pigs?

9-10 weeks

What is the age of sexual maturity in female guinea pigs?

4-6 weeks

What is the age of sexual maturity in male and female hamsters, rats and mice?

6-8 weeks

When do you want to determine the sex of rabbits/rodents?

before they reach sexual maturity

Why do you want to determine the sex of rabbits/rodents before they reach sexual maturity?

so you can separate male and female before able to breed

Is it easy to determine the sex of young animals?

NO

What is the main method to determine is a juvenile rodent is male or female?

anogenital distance

anogenital distance

distance between the anus and urethral opening

What is the difference between the anogenital distance in male and female rodents?

females closer, males further apart

Is the left male or female?

female

Is the right male or female?

male

Is the left male or female?

male

Is the right male or female?

female

Is the left male or female?

female

Is the right male or female?

male

How do you identify male rats, mice and hamsters?

• testes visible in scrotum

• no visible nipples

How do you identify female rats, mice and hamsters?

visible nipples

What shape is the preputial orifice in male guinea pigs?

i shape

How do you identify male guinea pigs?

• preputial orifice is round - forms “i” shape

• penis can be extruded

• large testes in adult males

How do you extrude the penis of a male guinea pig?

gentle pressure cranial to prepuce

How can you identify female guinea pigs?

anogenital area is “Y” shaped

Do both male and female guinea pigs have a pair of inguinal nipples?

YES

What shape is the preputial orifice in male rabbits?

round

How do you identify male rabbits?

• round preputial orifice

• penis can be extruded with gentle pressure cranial to prepuce

• large testes in adult males

How do you identify female rabbits?

slit-like vaginal opening (when apply gentle pressure around genitals)

What is the duration of a hamster, rat, mouse or gerbil’s oestrus cycle?

4-6 days

What is the duration of oestrus in a hamster, rat, mouse or gerbil?

10-24hrs

What are the ovulation characteristics of hamsters, rats, mice or gerbils?

polyoestrus, spontaneous ovulation

What is the gestation period of hamsters, rats, mice and gerbils?

15-26 days (species dependent)

Do hamsters, rats, mice, gerbils, guinea pigs and rabbits have post-partum oestrus?

YES

What is the duration the oestrus cycle of guinea pigs?

15-17 days

What is the duration of oestrus in guinea pigs?

6-11hrs

What are the ovulation characteristics of guinea pigs?

polyoestrus, spontaneous ovulation

How long is the gestation period of guinea pigs?

63 days (2 months)

What is the duration of the oestrus cycle of a rabbit?

no regular oestrus cycle

What are the ovulation characteristics of rabbits?

polyoestus, induced ovulation

How long is the gestation period of rabbits?

31-33 days

Are rabbits seasonal or non-seasonal breeders?

non-seasonal

What do rabbits have instead of a regular oestrus cycle?

cycle of mating receptivity

How many days are rabbits receptive in their cycle of mating receptivity?

approx 14 of every 16 days

How common is it for false pregnancy to occur in rabbits?

fairly common

When does false pregnancy (rabbits) occur?

if mated but no fertilisation or due to stress

How many kits are there per rabbit litter?

6-8

When can rabbits be weaned?

5-8 weeks

What are rabbit kits born like?

altricial

altricial

helpless, naked, blind and death

Are guinea pigs seasonal or non-seasonal?

non-seasonal

How many pups are there usually per litter in guinea pigs?

3-4

In what way are guinea pigs born?

precocial

precocial

eat solid food from birth, able to see, hear, run around

When can you wean guinea pigs?

2-4 weeks old

Why are guinea pigs problematic in parturition?

narrow pelvic canal and large babies

What does parturition require the separation of?

the 2 halves of the pelvis at the pubic symphysis

In young guinea pigs, what is the pubic symphysis like?

fibrocartilaginous (and becomes soft and stretchy in response to relaxin)

When does the pubic symphysis in guinea pigs remain fibrocartilaginous?

if a sow has a litter when young

What happens to the pubic symphysis is a sow does not have a litter when young?

becomes calcified and permanently fuses together

In guinea pigs, at what age does the pubic symphysis become calcified?

8-12 months

What are guinea pigs at high risk of if they have their first litter after 8 months of age?

dystocia

At what age are guinea pigs at high risk of dystocia when having their first litter?

after 8 months

Are hamsters, rats, mice and gerbils seasonal or non-seasonal breeders?

non-seasonal

How many pups are there in litters of hamsters, rats, mice and gerbils?

10-11

How are hamsters, rats, mice and gerbils born?

altricial

When do you wean hamsters, rats, mice and gerbils

3 weeks

What are the 3 options when controlling reproduction of rabbits and rodents?

1. keep males and females separate

2. surgical neutering

3. chemical neutering

What are the pros of separating males and females when controlling reproduction?

• quick

• easy

• cheap

What are the cons of separating males and females when controlling reproduction?

• welfare implications

• increased risk of diseases in entire animals

• requires additional space for housing

How should rabbits be kept?

pairs or small groups

What is the ideal pairing of rabbits to keep in?

neutered male with neutered female or 2 neutered males (2 neutered females may be ok)

What do entire rabbits often become?

territorial and aggressive resulting in fighting and bullying

Why is it inappropriate to house rabbits with other species as companions?

cannot express normal social behaviour

Are guinea pigs, mice and rats sociable or not naturally sociable animals?

highly sociable

How should guinea pigs, mice and rats be kept?

single-sex groups or pairs or harems

Are hamsters naturally sociable or not naturally sociable?

not naturally sociable

How are hamsters best kept?

alone

What breed of hamster can be housed in pairs if introduced when young?

dwarf hamsters

Spay

removal of ovaries and uterus

castrate

removal of testes

What common rabbit/rodent pet species is routinely surgically neutered?

rabbits

How many weeks can males remain fertile for after castration?

3 weeks

What are the pros of surgical neutering?

• reduces aggression

• reduced risk of diseases

What are their very high risk of in entire female rabbits?

uterine tumours

What is there a very high risk of in entire female rabbits?

mammary tumours

What are the cons of surgical neutering?

• cost

• anaesthetic risk

• post-op complications

• need to wait >5 months before spaying

What age can you castrate from?

10 weeks

What can be used (off license) for chemical neutering of male and female rats?

hormonal implant

What are the pros of chemical neutering?

• quick

• minimally invasive

• reduced risk of mammary tumours (rats)

What are the cons of chemical neutering?

• anaesthetic required

• may need to repeat

• cost

When is a hormonal implant given?

when reach sexual maturity

What advice should you give owners regarding neonates?

minimal intervention best

Why is minimal intervention regarding neonates best?

may abandon/eat young if stressed

How many times a day do rabbits usually feed their young?

once or twice a day

When do neonates remain in their nest until?

they’ve opened their eyes (7-10 days)

Should you neuter the male or female animal if you can only do one?

female