Key Points

• Intact female guinea pigs are “sows” and intact males are “boars”.
• Mature boars have actually distinct scrotal pouches and big testes.
• Male guinea pigs have actually a few accessory intercourse glands, including big, paired seminal vesicles or vesicular glands, which are often seen erroneously as uterine horns.
• Puberty does occur at around 2 months in females and between 2-3 months in males.
• The symphysis that is pubic within the last times of maternity.
• Separation for the symphysis that is pubic be inadequate in sows bred after 7-8 months of age and dystocia may result in these people. Other prospective reasons for dystocia consist of obesity and fetal size that is large.
• Sows frequently give delivery to 2-4 big, 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. Reduce the chance of pregnancy toxemia by motivating workout, preventing obesity, and minimizing stress in the sow that is pregnant.
• Unilateral or bilateral cysts that are ovarian quite typical, especially in older sows.
• Ovariohysterectomy or ovariectomy is preferred to stop the introduction of ovarian cysts as well as other problems that are reproductive non-breeding friend sows.

Introduction

Guinea pigs are helpful in reproductive studies simply because they share numerous traits that are reproductive humans (Fig 1). 26 Like humans, guinea pigs have a very hemochorial placenta, by which maternal bloodstream will come in direct experience of 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 individual condition. 26 needless to say, some popular features of guinea pig reproductive anatomy and physiology are distributed to other people of purchase Rodentia, as well as other features are unique for this unique species. This short article ratings structure and physiology of this guinea pig reproductive tract and summarizes some clinically significant medical issues.

Figure 1.Guinea pigs (Cavia porcellus) are helpful in a lot of reproductive studies.

Intact male guinea pigs, or “boars”, enter puberty between 70-90 times, nonetheless men start to show intimate behavior, such as for example mounting, at four weeks of age. 9 , 17 , 23 At 2 months, boars commence to ejaculate while mounting. 23 Expression of intimate behavior and development that is physical notably suppressed in the event that boar is housed having its mom and/or siblings. 11

Boars are usually bigger than females, with both sexes having a solitary couple of inguinal mammae. 5 Mature boars possess big, paired testes, that are situated on either region of 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 have not descended by 4 months of age, the guinea pig is highly recommended cryptorchid. 9 The inguinal canals remain available for a lifetime. 9 , 19 to avoid herniation post-castration, many clinicians start using a shut method or a modified available strategy, where in actuality the tunica is roofed into the suture that is used to tie from the spermatic cable and vessels. 32

Figure 2.Gross image regarding the testicle (arrow) in an adult boar (Cavia porcellus). The epididymis lies across the surface that is dorsolateral of testis. The tail associated with epididymis offers increase into the ductus deferens. Credit: Drury Reavill, DVM, DABVP (Avian Training), DACVP. Click image to expand.

Clinical Suggestion: Although big, paired testes are unmistakeable in mature boars, gender identification may be challenging in young pups. In the event that testicles aren’t apparent, sexing are facilitated by putting mild stress at the beds base regarding the prepuce to partially extrude your penis. 23

The penis that is s-shaped of the human anatomy and glans. Guinea pigs have a penis that is os that is discovered inside the dorsal area regarding the whole amount of the glans. 9 , 19 Like many hystricomorph rodents, your penis comes with moment, saw-toothed white spurs arranged dorsolaterally in 2 synchronous lines through the urethral orifice to your glans. There is an intromittent sac on the ventral surface for the glans penis. 9 During erection, the sac everts and two styles that are horny. 5 , 9 , 23 the event of the 3-5 mm long projections is unknown. 9

Male reproductive glands include the seminal vesicles (vesicular glands), coagulating glands, bulbourethral glands, as well as the prostate (Fig 3). 5 , 27 A rudimentary gland that is preputial additionally be contained in the boar. 9

Figure 3. Reproductive anatomy 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 enlarge.

• 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 seminal vesicles can be recognised incorrectly as uterine horns.

Each hair follicle associated with the guinea pig is related to an androgen-dependent sebaceous gland. These glands are numerous across the relative straight back and are found round the anal area, where they’ve been called the caudal gland or “grease gland”. 9 , 23 The caudal gland is much more developed within the boar and it is employed for fragrance marking (Fig 4). Boars usually rub or hit their rump against an area, therefore the secretions deposited act as a sexual attractant and to mark territory. 9 , 23

Figure gland that is 4.Caudalbig arrow) and perineum (little arrow) in a male guinea pig (Cavia porcellus). Supply: Uwe Gille via Wikimedia Commons. Click image to expand.

Puberty happens around 2 months of age into 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 an estrous period between 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 distinct sound that is guttural. Estrus lasts 6-11 hours, and with this time the sow shows lordosis, curvature associated with the back with elevated sides, in addition to vulvar dilation. 23

The sow possesses a pair that is single of mammary glands with an individual couple of inguinal mammary nipples (Fig 5), nevertheless supernumerary nipples are typical. 9 , 19 , 22 in comparison to the boar, the sow’s nipples are much longer and much more prominent. 9

Figure 5.Both male and guinea that is female (Cavia porcellus) have just one couple of inguinal mammary glands. Supply: Drury Reavill, DVM, DABVP (Avian Training), DACVP. Click image to expand.

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). Source: Drury Reavill, DVM, DABVP (Avian training), DACVP Click image to expand.

Figure 7.Gross view for the uterine horns (little arrows) and body (big arrow) in a guinea pig (Cavia porcellus). Supply: Drury Reavill, DVM, DABVP (Avian Training), DACVP. Click image to expand.

The vaginal opening in hystricomorph rodents is sealed with an epithelial membrane called the vaginal closure membrane during anestrus and pregnancy. The membrane starts at estrus, Day 26 or 27 of gestation, as well as parturition in lots of pets. 19 , 22 , 23 , 29 The sow features a Y-shaped despair in perineal cells. The vulvar opening lies at the intersection of this branches therefore the rectum is located during 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) and also the anal area (yellow arrow). Supply: Dorcas O’Rourke, DVM, MS, DACLAM. Click image to expand.

Copulation

whenever a receptive feminine is introduced, the boar starts to purr and sway their posterior back and forth, while circling, and quite often cleaning up against the sow if not spraying urine in the sow. In the event that feminine is unreceptive, aggressive male behavior might be seen such as for instance barbering hair regarding the neck that is female’s. 19 a female that is receptive permit the male to sniff and lick her anogenital region. 6 , 11 , 19 She assumes the lordosis place and permits the male to mount her. Whether ejaculation happens or otherwise not, the male will perform vaginal grooming by dragging his perineum across the cage flooring. Meanwhile the feminine doubles over and makes use of her lips to groom her genitals. 19 Mating frequently does occur at night. 8

Copulation is verified because of the presence of a strong, rubbery deposit inside the vagina called https://adult-friend-finder.org/about.html the copulatory or plug that is vaginal made up of an excellent mass of ejaculatory fluid. 23 there are many theories regarding the purpose of the copulatory plug in rodents, including semen storage space, avoidance of sperm leakage, advertising of semen transportation, and/or to stop later fertilization by other men. 23 The copulatory plug falls out a long time after mating. 23

The normal guinea pig maternity persists 68 times, with a reported array of 59-72 times. 9 , 19 , 23 These times differ with stress, parity, and size that is litter. 23 Normal litter size is 2-4 pups with a selection of 1-13 pups. 23 clear stomach distension just isn’t seen until late gestation. 8