Er Reproduction Part 3: Fertilization, Gestation, Parturition

Vary from species to species.

In 85% of females.

"After you."
"No, no, after you!"
"No, but I insist!"

In sexual reproduction, the nucleus of a sperm and ovum fuse together in a process called fertilization. This fusion forms a zygote, which is the initial stage of a new organism. The zygote contains the combined genetic material from both parents and will develop into a morula, which is a solid ball of cells, and eventually into an embryo. The other options, cytoplasm and head, do not accurately represent the fusion of genetic material or the formation of a zygote.

In the queen, stage 2 parturition may take several days, but it is uncommon. This means that while it is possible for the second stage of labor in a queen (female cat) to last for several days, it is not a typical or common occurrence. Most queens will complete the second stage of labor within a shorter timeframe.

"Lochia" is a term used to describe the discharge that occurs after childbirth. It consists of blood, mucus, and tissue from the lining of the uterus. This discharge is a normal part of the postpartum period and typically lasts for a few weeks.

The placenta serves as a vital organ during pregnancy, facilitating the transfer of nutrients from the mother to the developing fetus. It also plays a crucial role in eliminating waste products and toxins from the fetal bloodstream. This exchange of substances occurs through the placental barrier, which allows for the diffusion of oxygen, nutrients, and waste products between the maternal and fetal blood supplies. Overall, the placenta acts as a lifeline for the fetus, ensuring its nourishment and removing harmful substances.

During early development, the embryo undergoes significant changes and transforms into the fetus and placenta. This transformation involves the formation of both an embryonic disk and a yolk sac of nutrients. The embryonic disk is a structure that gives rise to the various tissues and organs of the developing organism, while the yolk sac provides essential nutrients for the embryo's growth and development. Together, these structures play crucial roles in the progression from embryo to fetus and the establishment of the placenta, which is responsible for nutrient exchange between the mother and the developing fetus.

Pseudogestation is a condition in which a female animal experiences an increase in progesterone levels after estrus, regardless of whether she is pregnant or not. This period, known as diestrus, typically lasts for 57-58 days. During pseudogestation, the female may exhibit signs of pregnancy, such as nesting behavior and mammary gland development, even though she is not actually carrying any offspring. This phenomenon is believed to be caused by hormonal imbalances and can occur in various species, including dogs, cats, and rabbits.

Stage 3 parturition is the correct answer because it refers to the final stage of childbirth, which involves the expulsion of the placenta. This stage occurs after the baby is born and is completed when the placenta is delivered.

Stage 2 parturition is the correct answer because it refers to the stage of labor where the fetuses are expelled through the cervix and vagina. This stage is characterized by active muscle contractions, which typically last for 20-60 minutes per pup. Stage 1 parturition refers to the initial stage of labor where the cervix begins to dilate, while Stage 3 parturition refers to the expulsion of the placenta after the birth of the puppies. Stage 4 parturition is not a recognized stage of labor.

After the birth of a pup, the placenta is usually passed within 5-15 minutes. This is because the placenta is necessary for the exchange of nutrients and waste between the mother and the developing fetus during pregnancy. Once the pup is born, the placenta is no longer needed and is expelled from the mother's body. The prompt suggests that the correct answer is 5-15 minutes, indicating that this is the typical timeframe for the placenta to be passed after birth.

The symptoms mentioned in the question, such as restlessness, nesting, nervousness, panting, anorexia, and cervical dilation, are indicative of the first stage of parturition, also known as labor. During this stage, the cervix begins to dilate and the uterus starts contracting, preparing for the birth of the offspring. These symptoms are commonly observed in animals before they give birth, indicating that the process of labor is about to begin.

Normal lochia refers to the vaginal discharge that occurs after giving birth. In dogs, it typically lasts 8-10 weeks, while in cats it lasts 3 weeks. The discharge is usually reddish brown in color and should not have a foul odor. This is a normal part of the postpartum healing process and indicates that the uterus is shedding its lining and healing properly. The presence of a foul odor or a different color may indicate an infection or other complications. The option "Reddish brown, no foul odor" accurately describes the characteristics of normal lochia.

Capacitation is the process by which spermatozoa undergo physiological changes that enable them to become capable of fertilizing an egg. During capacitation, the spermatozoa gain the ability to swim with greater motility and acquire the ability to penetrate the egg. Maturing refers to the process of the spermatozoa developing and reaching their full functional potential. Therefore, the explanation for the correct answer is that capacitation is the process by which spermatozoa move into the uterus and up oviducts with swimming action, and then spend time there maturing to fertilize eggs.

Diestrus is considered a better estimate than the breeding date because diestrus is a stage in the reproductive cycle of mammals that follows estrus. During diestrus, the female is no longer receptive to mating and the uterine lining prepares for potential pregnancy. The breeding date refers to the specific date when mating occurred, which may not accurately reflect the stage of the reproductive cycle. Diestrus, on the other hand, provides a more reliable indication of the timing of mating and the potential for pregnancy.

12-24 hours.

In stage 2 of parturition, which is the active labor stage, the puppies are born. The correct answer of 2 hours suggests that there should not be more than a 2-hour gap between the birth of each puppy. This ensures that the birthing process is progressing smoothly and that each puppy is delivered within a reasonable timeframe. A longer gap between puppies could indicate a potential problem or delay in the labor process.

Stage 1 parturition refers to the early phase of labor, where the cervix begins to dilate and the uterus starts contracting. The average duration of this stage is 6-12 hours, which means that most women will experience this phase within this time range. However, it is important to note that stage 1 parturition can last up to 36 hours in some cases. This means that there is a possibility for labor to take longer than the average time frame, but it is less common for it to extend beyond 36 hours.

The behavior described in the question, such as biting membranes, chewing the umbilicas, eating placentas, and vigorously licking the offspring, is considered normal maternal behavior. This behavior is commonly observed in many animal species, including humans, and is essential for the survival and well-being of the newborn. It helps to stimulate the newborn's breathing, remove any potential obstacles, and establish a bond between the mother and her offspring.

After fertilization, the zygote undergoes multiple divisions, resulting in the formation of a blastocyst. The blastocyst is a stage in embryonic development where the zygote has differentiated into two distinct cell types: the inner cell mass and the outer trophoblast. This stage is important for implantation in the uterus, as the trophoblast cells will eventually form the placenta, while the inner cell mass will develop into the embryo itself. Therefore, the correct answer is Blastocyst.

After eating placenta, it is possible for a person to experience vomiting and diarrhea. Additionally, 24 to 36 hours after giving birth, black and watery discharge may occur.

Stage 2 parturition, also known as the active labor stage, typically takes 3-6 hours in the female dog. However, it may last up to 24-36 hours. This stage involves the actual delivery of the puppies, with strong uterine contractions and the expulsion of the fetuses. The duration can vary depending on factors such as the size of the litter, the individual dog's reproductive history, and any potential complications during the birthing process.

Pseudogestation is a condition where a non-pregnant individual exhibits signs and symptoms of pregnancy. Mibolerone and cabergoline are both medications that can cause pseudogestation. Mibolerone is a synthetic androgen that can stimulate the production of progesterone, leading to pseudogestation. Cabergoline, on the other hand, is a dopamine agonist that can increase prolactin levels, which can also result in pseudogestation. Progestogen is a general term for synthetic progesterone, which can also potentially cause pseudogestation. Aubergine, or eggplant, has no known association with pseudogestation.

Signs of pseudopregnancy will return when therapy is stopped.

As progesterone levels decline, some pseudopregnant females may experience mammary development, lactation, maternal behavior, behavioral changes, and discomfort. These are common physiological and behavioral changes that occur in response to hormonal fluctuations during pseudopregnancy. Vocalizing and PU/PD (polyuria/polydipsia) are not typically associated with progesterone decline in pseudopregnant females.

The correct answer includes multiple methods of diagnosing gestation. Palpation around day 21 post diestrus is a method of feeling the uterus to detect pregnancy. Hormone assay, specifically measuring relaxin hormone levels on day 20 post diestrus, can also indicate pregnancy. Ultrasonography involves using sound waves to visualize the fetus in the uterus. Radiography, specifically around 45 days post LH (luteinizing hormone), can show the presence of fetal skeletons. These methods are all effective in diagnosing gestation at different stages and provide a comprehensive approach to confirming pregnancy.