Donor Species And Environment

Factors influencing superovulatory response include the donor animal itself and its environment. Response is influenced by species, nutritional status, reproductive history, age, breed, and whether it has been treated previously. In terms of species, it is well recognized that a major limitation to ET in the buffalo is the low yield of transferable-quality embryos.[10] The method of superovulation, although differing in detail among species, is based on administering gonadotropin when it is possible to achieve uniform follicle growth in response to FSH treatment (Table 1).

FSH preparations suitable for ruminant species, pigs, and camelids are without effect in horses.[11] In human IVF programs, pituitary down-regulation of LH and FSH by GnRH has been widely employed. Such down-regulation is usually achieved in the human patient by way of a nasal spray.[12] In farm animals, however, the requisite prolonged administration of this preparation, involving repeated injections, is currently ruled out on the basis of cost. In small ruminants, conventional protocols for superovulation generally involved an initial priming period with progesterone/progestagen-releasing devices (12 days in ewes, longer in goats) and the administration of gonadotropin prior to or around the time of progesterone/progestagen withdrawal. Responses in small ruminants and deer[13] are broadly in line with those expected in cattle, in terms of ovulation rate and yield of transferable embryos. Superovulation can be induced in the gilt and sow by administering a single dose of PMSG at the start of the follicular phase of the estrous cycle.[14] In camelids, which are induced ovulators, it is necessary to induce or simulate a luteal phase as a preliminary to the administration of gonadotropin.[15] In terms of environment, it is well established that seasonal changes in tropical and subtropical regions can markedly influence superovulatory response.

100 Pregnancy Tips

100 Pregnancy Tips

Prior to planning pregnancy, you should learn more about the things involved in getting pregnant. It involves carrying a baby inside you for nine months, caring for a child for a number of years, and many more. Consider these things, so that you can properly assess if you are ready for pregnancy. Get all these very important tips about pregnancy that you need to know.

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