Although this wedsite is about the fetal pig, i found it interesting. The graphics are good and the site is set up in three sections. 1. Anatomy, 2. Estrous cycle and 3. Embyonic and Fetal development. This website was designed by Dr. Wayne Singleton and Dr. mark Diekman and is about reproduction, physiology and anatomy of the sow. It is an understanding of the sows reproductive sysytem, and how it is essential for a successful mating program. A program that is held at the purdue university. This site provides beautiful dissections that are fresh and not what we have viewed in lab.
The anatomy part of this website goes on to explain that the ovaries are the main structures of fetal develpoment. They have 2 major function which are to produce hormones and ova. the infundibulum is the membrane around the ovary and the oviduct is the site for fetilization. The cervix is the site where sperm is deposited and the uterine horns are the passage ways for sprem to meet the ovum.
Estrous cycle, Estrus and Ovulation
The estrous cycle in the sow is normally a 21 day cycle. Non pregnant pigs display a estrus or standing heat throughtout the year. While the sow is nursing her young the estrus cycle will not be present. Follicles are formed on each ovary as the estrus approaches. Follicular growth is influenced by hormones from the pituitary gland. Granulosa cells within the follicle secretes estrogen which is responsible for estrus.
Fertilization, Embryonic and Fetal Development
Although 30-60 million sperm are deposited into to cervix, only a small percentage reach the oviduct.sperm can swim on there own so the cervix with its contractions help the sperm on their way. when fertilization happens the blastocysts enter the uterus and can migrate from one horn to another. The embryo is surrouneded by a serious of fluid filled membranes. Fetal orientation is random, meaning the fetus are facing different directions. Embryos which die become reabsored. The average geatation period from conception to birth is 114 days and the fetus is about 3 to 3 1/2 pounds.
By Wendy Silva
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