SIGNS OF PREGNANCY IN CAVIES
by Mette Lybeck Ruelokke (Mette the Vette)
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After a successful mating, life for the female cavy will go on as usual. The first sign of pregnancy is usually the absence of a new season approx. 16 days after mating; but only a few days later, when the sow is about 3 weeks pregnant, it is possible for the experienced breeder to feel slight swellings inside the belly. Each swelling represents a foetus in the womb.
A suitable method to feel such an early pregnancy is to place the pig with its front feet on a table lifting the rear end with two hands, one under each side of the belly. Place four fingers under the belly and thumbs on top, then press your thumbs gently downwards until you can feel from below. Stop pressing if you feel bowels or if the sow resists your examination. After a short break you can continue, and you'll soon learn to distinguish the different structures inside the belly; kidneys (just behind the ribs, usually only the left one can be felt), intestines (droppings are easily felt lying like pearls on a string) and the pregnant womb. Thoroughly feel your way through the belly from the middle outwards in all length from ribs to pelvis. After some practice you will be able to recognise smaller and smaller swellings earlier and earlier in pregnancy, the lower limit being about 3 weeks pregnant, where the diameter is like a five pence coin. Pregnancy swellings in early pregnancy are felt like tiny water-filled balls lying on a row on each side of the belly. Take care not to press too hard though.
At 4 weeks pregnant the swellings are still well separated and easy to distinguish, and an attempt can be made to determine the number of foetuses, but you will find that your guess will quite often be wrong. If you are unable to feel the foetuses lying in the womb, weighing the sow at regular intervals (i.e. once a week) is a suitable alternative. Whilst the weight the first couple of weeks is almost unchanged, a significant increase in weight can be seen from 4 weeks of pregnancy. The increase will of course depend on the number of foetuses and will continue throughout the pregnancy. Any weight loss in this period is a sign of illness e.g. caused by toxaemia or foetal death.
From 5 weeks onward the sow will become thicker every day, and if the boar has other mating duties, you can remove him now, but most sows appreciate the company and may be happier of kept together with another cavy (e.g. a young boar or sow)
Seven weeks after mating foetal movements are usually recognised, and these will become more and more pronounced. At the end of the pregnancy in is possible to see and feel a little leg moving around and to hear and feel the babies chewing. At this stage the sow may have become unbelievably big if she is carrying a large litter. The weight of the litter represents up to 50% of her total weight. Now it is definitely time to remove any boars, if a post partum mating is unwanted; and most sows will appreciate being left on their own.
After about 9 weeks of pregnancy the birth ways will start opening. This process can easily be felt on the pelvis, as the syphysis, which is the line where the two pelvic parts meet underneath will be widening. This widening will continue until it reaches a max. of 1-2 fingers width with 24 to 48 hours before parturition. To feel the pelvic widening, place a finger just in front of the vagina underneath the cavy. If you are not sure, try to compare the sow with another pig.
In late pregnancy the sow will be very restricted in her movements and move around reluctantly, but she must still have a good appetite and be bright, otherwise there is a risk of toxaemia developing.
Pregnancy lasts for approximately 10 weeks or, more exactly, 67-72 days, big litters tending to be born a few days earlier than a single baby. Sometimes literature indicates that pregnancy lasts for as little as 52 days, but in my (and several other's) opinion babies born before day 65 are premature and are likely to die.
Such a long pregnancy is unique amongst the rodents, and reflects the fact that cavy babies must be fully developed and able to escape from enemies from day 1, as cavies, unlike rats, and mice don't have underground burrows where the offspring can be kept safely whilst they grow up and develop hair, mobility and senses.
Mette Lybek Ruelokke