The guinea pig (Cavia porcellus) is a favorite friend animal and a research model that is common.

The guinea pig (Cavia porcellus) is a favorite friend animal and a research model that is common.

Key Points

  • Intact female guinea pigs are “sows” and intact males are “boars”.
  • Mature boars have distinct scrotal pouches and big testes.
  • 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 more or less 2 months in females and between 2-3 months in men.
  • The pubic symphysis separates within the last few times of maternity.
  • Separation for the symphysis that is pubic be insufficient 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 usually give birth to 2-4 big, precocial pups. Other rodent types generally speaking have actually big litters.
  • Pregnancy toxemia is definitely a cause that is important of mortality in guinea pigs. This disorder is most often noticed in primiparous, overweight sows in belated gestation. The prognosis is usually guarded. Minmise the chance of being pregnant 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 preferred to stop the introduction of ovarian cysts as well as other problems that are reproductive non-breeding companion sows.

Introduction

Guinea pigs are helpful in reproductive studies simply because they share numerous traits that are reproductive people (Fig 1). 26 Like people, guinea pigs have a very hemochorial placenta, for which maternal bloodstream will come in direct experience of the fetal chorion, also comparable trophoblast intrusion habits and uterine vasculature that is comparable. 20 , 23 , 26 The guinea pig’s gestation duration can be divided in to trimesters, analogous to your individual condition. 26 Of course, some top features of guinea pig reproductive anatomy and physiology are distributed to other users of purchase Rodentia, along with other features are unique for this unique species. This short article product reviews physiology and physiology of this guinea pig tract that is reproductive summarizes some clinically significant medical issues.

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

Intact guinea that is male, or “boars”, enter puberty between 70-90 times, but males 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 real development is considerably suppressed if the boar is housed featuring its mom and/or siblings. 11

Boars are usually bigger than females, with both sexes having a pair that is single of mammae. 5 Mature boars have big, paired testes, that are found on either part for the perineum in distinct, superficial scrotal sacs (Fig 2). 5 , 9 , 23 The testicles are frequently completely descended to the scrotum by 81 times. 2 In the event that testes never have descended by 4 months of age, the guinea pig is highly recommended cryptorchid. 9 The canals that are inguinal available for a lifetime. 9 , 19 to avoid herniation post-castration, numerous clinicians start using a shut method or even a modified available method, in which the tunica is roofed into 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 over the surface that is dorsolateral of testis. The end associated with the epididymis offers increase towards the ductus deferens. Credit: Drury Reavill, DVM, DABVP (Avian Training), DACVP. Click image to expand.

Clinical Suggestion: Although large, paired testes are clear in mature boars, sex identification are challenging in young pups. In the event that testicles aren’t apparent, sexing are facilitated by putting pressure that is gentle the beds base of this prepuce to partially extrude your penis. 23

The S-shaped penis comprises of a human anatomy and glans. Guinea pigs have a penis that is os which can be discovered inside the dorsal area associated with entire period of the glans. 9 , 19 Like other hystricomorph rodents, your penis even offers moment, saw-toothed white spurs arranged dorsolaterally in 2 synchronous lines through the urethral orifice to your glans. There’s also an intromittent sac on the ventral area associated with glans penis. 9 During erection, the sac everts and two horny styles protrude. 5 , 9 , 23 the event among these 3-5 mm projections that are long unknown. 9

Male glands that are reproductive the seminal vesicles (vesicular glands), coagulating glands, bulbourethral glands, together with prostate (Fig 3). 5 , 27 A rudimentary preputial gland may additionally be contained in the boar. 9

Figure 3. Reproductive structure regarding the 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 vesicles that are seminal 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 blind sacs lie 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 locks follicle associated with guinea pig is connected with an androgen-dependent sebaceous gland. These glands are numerous over the as well as will also be discovered across the anus, where these are generally 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, plus the secretions deposited act as a sexual attractant and to mark territory. 9 , 23

Figure 4.Caudal gland (big arrow) and perineum (little arrow) in a male guinea pig (Cavia porcellus). Source: Uwe Gille via Wikimedia Commons. Click image to enlarge.

Puberty happens around 2 months of age when you look at the guinea that is female or “sow”. 23 Peak reproduction is seen between 3-4 to 20 months and reproduction may 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, having an estrous period between 15-17 times (range 13-21 times). 19 Sows display distinct indications of estrus and proestrus. During proestrus, sows are more active, chasing cage mates around, swaying their hindquarters, and creating a definite sound that is guttural. Estrus lasts 6-11 hours, and in this right time the sow shows lordosis, curvature of this back with elevated sides, 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 typical. 9 , 19 , 22 in comparison to 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) possess an individual set of inguinal mammary glands. Supply: Drury Reavill, DVM, DABVP (Avian Training), 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 regarding the uterine horns (little arrows) and human body (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 vulvar opening lies at the intersection regarding the branches in addition to anal area is based at the root of the Y (Fig 8). 23

Figure 8.Y-shaped despair when you look at the perineum of a guinea pig sow (Cavia porcellus), illustrating the vulva (white arrow) as well as the rectum (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 contrary to the sow and on occasion even spraying urine during the sow. If the feminine is unreceptive, aggressive male behavior could be seen such as for instance barbering hair in the female’s throat. 19 A receptive feminine will let the male to sniff and lick her anogenital area. 6 , 11 , 19 She assumes the lordosis place and enables a man to mount her. Whether ejaculation happens or otherwise not, the male will perform genital grooming by dragging their perineum across the cage flooring. Meanwhile the doubles that are female and uses her lips to groom her genitals. 19 Mating often happens at nighttime. 8

Copulation is confirmed by the existence of a company, rubbery deposit in the vagina called the copulatory or plug that is vaginal made up of a great mass of ejaculatory fluid. 23 there are many theories from the purpose of the copulatory plug in rodents, including semen storage space, avoidance of semen leakage, advertising of semen transportation, and/or to stop later on fertilization by other males. 23 The copulatory plug falls out a long time after mating. 23

The guinea that search adult friend finder is average pregnancy persists 68 times, with a reported array of 59-72 days. 9 , 19 , 23 These times differ with stress, parity, and size that is litter. 23 Normal litter size is 2-4 pups with a variety of 1-13 pups. 23 Obvious stomach distension is certainly not seen until belated gestation. 8

0
HeartHeart
0
HahaHaha
0
LoveLove
0
WowWow
0
YayYay
0
SadSad
0
PoopPoop
0
AngryAngry
Voted Thanks!