- Intact guinea that is female are “sows” and intact males are “boars”.
- Mature boars have actually distinct scrotal pouches and testes that are large.
- Male guinea pigs have actually a few accessory intercourse glands, including big, paired seminal vesicles or vesicular glands, that can easily be recognised incorrectly as uterine horns.
- Puberty does occur at around 2 months in females and between 2-3 months in men.
- The pubic symphysis separates within the last few times of maternity.
- Separation associated with the pubic symphysis may be insufficient in sows bred after 7-8 months of age and dystocia may result in him or her. Other possible factors behind dystocia consist of obesity and large fetal size.
- Sows often give birth to 2-4 large, precocial pups. Other rodent types generally speaking have actually big litters.
- Pregnancy toxemia is a cause that is important of mortality in guinea pigs. This disorder is frequently noticed in primiparous, overweight sows in belated gestation. The prognosis is oftentimes guarded. Minmise the chance of maternity toxemia by motivating workout, preventing obesity, and minimizing stress in the sow that is pregnant.
- Unilateral or bilateral ovarian cysts are quite typical, especially in older sows.
- Ovariohysterectomy or ovariectomy is advised to avoid the introduction of ovarian cysts along with other problems that are reproductive non-breeding friend sows.
Guinea pigs are helpful in reproductive studies simply because they share numerous reproductive characteristics with people (Fig 1). 26 Like people, guinea pigs have a very hemochorial placenta, by which maternal bloodstream is available in direct connection with the fetal chorion, in addition to comparable trophoblast intrusion habits and uterine vasculature that is comparable. 20 , 23 , 26 The guinea pig’s gestation duration may also be split into trimesters, analogous towards the condition that is human. 26 needless to say, some popular features of guinea pig reproductive anatomy and physiology are distributed to other people in purchase Rodentia, along with other features are unique for this species that is special. This short article ratings physiology and physiology associated with guinea pig reproductive tract and summarizes some clinically significant medical issues.
Figure 1.Guinea pigs (Cavia porcellus) are helpful in lots of studies that are reproductive.
Intact male guinea pigs, or “boars”, enter puberty between 70-90 days, nevertheless men commence to show intimate behavior, such as for example mounting, at four weeks of age. 9 , 17 , 23 At 2 months, boars start to ejaculate while mounting. 23 Expression of sexual behavior and real development is notably suppressed in the event that boar is housed using its mom and/or siblings. 11
Boars are generally bigger than females, with both sexes having a single set of inguinal mammae. 5 Mature boars have big, paired testes, that are found on either part associated with the perineum in distinct, superficial scrotal sacs (Fig 2). 5 , 9 , 23 The testicles are frequently completely descended in to the scrotum by 81 times. 2 In the event that testes never have descended by 4 months of age, the guinea pig should be thought about cryptorchid. 9 The canals that are inguinal available for a lifetime. 9 , 19 to avoid herniation post-castration, numerous clinicians utilize a shut strategy or perhaps a modified available strategy, where in actuality the tunica is roofed when you look at the suture which is used to connect from the spermatic cable and vessels. 32
Figure image that is 2.Gross of testicle (arrow) in an adult boar (Cavia porcellus). The epididymis lies across the surface that is dorsolateral of testis. The end associated with the epididymis offers rise into the ductus deferens. Credit: Drury Reavill, DVM, DABVP (Avian Training), DACVP. Click image to expand.
Clinical Suggestion: Although big, paired testes are clear in mature boars, sex identification could be challenging in young pups. In the event that testicles aren’t obvious, sexing can be facilitated by placing mild stress at the bottom of this prepuce to partially extrude your penis. 23
The S-shaped penis comprises of the human anatomy and glans. Guinea pigs have a penis that is os which will be discovered inside the dorsal area for the whole duration of the glans. 9 , 19 Like many hystricomorph rodents, your penis even offers minute, saw-toothed white spurs arranged dorsolaterally in 2 synchronous lines through the urethral orifice to your glans. Additionally there is a sac that is intromittent the ventral area associated with glans penis. 9 During erection, the sac everts and two styles that are horny. 5 , 9 , 23 the big event among these 3-5 mm long projections is unknown. 9
Male reproductive glands include the seminal vesicles (vesicular glands), coagulating glands, bulbourethral glands, while the prostate (Fig 3). 5 , 27 A rudimentary gland that is preputial be contained in the boar. 9
Figure 3. Reproductive structure of this guinea pig (Cavia porcellus) boar. (A) seminal vesicle (B) testis C) vas deferens (D) anterior prostate gland or coagulating gland (E) urinary bladder (F) Cowper’s or bulbourethral gland (G) urethra (H) penis (we) epididymis. Picture credit: Drs. Craig Franklin and Cindy Besch-Williford. Click image to expand.
- The big, clear, smooth seminal vesicles are the biggest reproductive glands of this boar, calculating as much as 100 mm in total and 6-9 mm in diameter. These long, coiled, paired sacs that are blind ventral to the ureters and go into the urethra by a couple of ducts instantly caudodorsal towards the ductus deferens. 9 , 19 , 23 , 27
Clinical Suggestion: The big, paired vesicles that are seminal be recognised incorrectly as uterine horns.
Each hair follicle associated with guinea pig is related to an androgen-dependent sebaceous gland. These glands are numerous across the straight back and may also be discovered round the rectum, where these are generally called the caudal gland or “grease gland”. 9 , 23 The caudal gland is much more developed when you look at the boar and it is employed for fragrance marking (Fig 4). Boars usually rub or push on their rump against an area, in addition to secretions deposited act as a sexual attractant and to mark territory. 9 , 23
Figure 4.Caudal gland (large arrow) and perineum (little arrow) in a male guinea pig (Cavia porcellus). https://adult-friend-finder.org/about.html Source: Uwe Gille via Wikimedia Commons. Click image to expand.
Puberty happens around 2 months of age within the feminine guinea pig or “sow”. 23 Peak reproduction is seen between 3-4 to 20 months and reproduction might carry on until 4-5 years old. 19 , 23 Guinea pigs are seasonally polyestrous and breed year-round in captivity. 9 , 23 Sows are spontaneous ovulators, by having a cycle that is estrous 15-17 times (range 13-21 times). 19 Sows display distinct signs and symptoms of proestrus and estrus. During proestrus, sows are more active, chasing cage mates around, swaying their hindquarters, and creating a definite guttural noise. Estrus lasts 6-11 hours, and in this time the sow shows lordosis, curvature regarding the back with elevated hips, in addition to vulvar dilation. 23
The sow possesses a pair that is single of mammary glands with just one couple of inguinal mammary nipples (Fig 5), nevertheless supernumerary nipples are normal. 9 , 19 , 22 in comparison with the boar, the sow’s nipples are much much longer and much more prominent. 9
Figure 5.Both male and guinea that is female (Cavia porcellus) have just one set of inguinal mammary glands. Supply: Drury Reavill, DVM, DABVP (Avian Practice), DACVP. Click image to enlarge.
Sows have paired ovaries and a bicornuate womb, composed of paired uterine horns, an uterine that is short, and just one os cervix (Fig 6, Fig 7). 5 , 9 , 23
Figure 6.View of just one uterine horn (arrow) in mature guinea pig (Cavia porcellus). Supply: Drury Reavill, DVM, DABVP (Avian training), DACVP Click image to expand.
Figure 7.Gross view associated with uterine horns (little arrows) and human anatomy (big arrow) in a guinea pig (Cavia porcellus). Supply: Drury Reavill, DVM, DABVP (Avian Training), DACVP. Click image to expand.
During anestrus and pregnancy, the genital opening in hystricomorph rodents is sealed having an epithelial membrane called the genital closing membrane layer. The membrane layer starts at estrus, 26 or 27 of gestation, and at parturition in many animals day. 19 , 22 , 23 , 29 The sow possesses Y-shaped despair in perineal cells. The opening that is vulvar at the intersection regarding the branches therefore the rectum is situated at the foot of the Y (Fig 8). 23
Figure 8.Y-shaped despair into the perineum of the guinea pig sow (Cavia porcellus), illustrating the vulva (white arrow) plus the anal area (yellow arrow). Supply: Dorcas O’Rourke, DVM, MS, DACLAM. Click image to expand.
Whenever a female that is receptive introduced, the boar starts to purr and sway their posterior back and forth, while circling, and often cleaning contrary to the sow and on occasion even spraying urine during the sow. In the event that feminine is unreceptive, aggressive male behavior can be seen such as for instance barbering hair from the female’s throat. 19 A receptive female will enable the male to sniff and lick her anogenital area. 6 , 11 , 19 She assumes the lordosis place and permits the male to mount her. Whether ejaculation does occur or perhaps not, a man shall perform vaginal grooming by dragging their perineum over the cage flooring. Meanwhile the feminine doubles over and makes use of her lips to groom her genitals. 19 Mating frequently happens at night. 8
Copulation is verified because of the existence of a strong, rubbery deposit in the vagina called the copulatory or genital plug, made up of a great mass of ejaculatory fluid. 23 there are many theories in the function of the copulatory plug in rodents, including semen storage space, avoidance of semen leakage, promotion of semen transportation, and/or to stop later on fertilization by other men. 23 The copulatory plug falls out a long time after mating. 23
The typical guinea pig maternity persists 68 times, with a reported variety of 59-72 times. 9 , 19 , 23 These times differ with stress, parity, and size that is litter. 23 average size that is litter 2-4 pups with a variety of 1-13 pups. 23 clear stomach distension isn’t seen until belated gestation. 8