Details Title: ANS 327 MT 2 Questions Description: Yup Total Flash Cards: 38 Created: 11/17/2008 09:03:45		New Users: To study from this flashcard set, or to create your own your own study flash cards, REGISTER HERE. Existing Users: CLICK HERE. Additional Agriculture Flashcards
Cards in this set: Term Define parturition Definition Parturition is the expulsion of both fetus and fetal membranes Term What is responsible for inducing parturition? Definition Fetal cortisol- released from pituitary Term Describe general Stage I parturition Definition Cervical dilation,initiation of myometrial contractions, chorioallontoic membranes rupture and release allantoic fluid Term Fetal endocrine events prior to parturition Definition stressors trigger fetal hypothalamus to release corticotropon releasing hormone (CRH) --> stimulates release of adrenocorticotropic hormone (ACTH) from posterior pituitatry --> stimulates release of cortisol from the adrenal gland Term Maternal endocrine events prior to parturition Definition Progesterone declines, estradiol increases, PGF2a increases and then plummets shortly after parturition Term Enzymes released once fetal cortisol is released Definition 17a hydroxylase, C17-20 lyase, aromatase and they convert prostaglandin to estradiol Term physiologic importance of prostaglandin decline Definition removes prostaglandin block from myometrial contractions, allows for full contractility of myometrium Term physiologic importance of the increase in estradiol Definition Estradiol causes the secretion of cervical mucus, helping aid in parturition Term Physiologic importance of change in PGF2a Definition Causes regression of CL (helping lower prostaglandins being released from CL),works synergistically with estradiol to increase myometrial contractility Term General stage II parturition Definition powerful myometrial contractions as well as abdominal contractions, fetus into cervical canal triggers stretch receptors --> stimulates oxytocin release from pituitary --> stimulates release of prostaglandins helping increase power of myometrial contractions, delivery of fetus marks end of stage II Term General stage III parturition Definition Myometrial contractions still present but less powerful and less frequent, fetal membranes expelled Term indication of parturition onset (cattle) Definition udder is edematous and may leak colostrum, pelvic ligaments relax so gluteal muscles relax and tail head appears raised, vulva becomes edematous and vulvar cleft elongates Term stage I signs (cattle) Definition restlessness, arched back, extended tail, shifting weight, seeking isolation, straining of abdominal muscles at end of stage I Term length of stage I (cattle) Definition ~6 hrs (shorter 3-4 hrs in mature cows, longer in first time heifers up to 24 hours) Term describe passive phase of cervical dilation Definition external os dilates while internal os remains closed Term describe active phase of cervical dilation Definition strong contractions maneuver fetus into cervical canal, causes stretch, induces release of oxytocin Term during start of stage II, is amnion in cattle still intact or ruptured? Definition Intact Term When/how does placental separation occur in cattle? What does this do to the fetus? Definition Gradually in the 2nd stage. Makes fetus hypoxic but not usually acutely anoxic Term how long is stage II in cattle? Definition up to 8 hours, 6 is ideal Term How long are myometrial contractions observable after parturition? Definition 2-4 days Term What is dystocia? Definition Dystocia is difficulty with parturition because either the 1st or 2nd stage were unable to be completed Term what are the most common causes of dystocia? Definition fetopelvic disproportion, primary uterine inertia, secondary uterine inertia Term what is primary uterine inertia? Definition failure of the myometrium to contract enough to push the fetus into the cervical canal despite cervical dilation, parturition does not proceed past 1st stage Term what is secondary dystocia? Definition failure to expel the fetus, muscle exhaustion and/or cessation of responsiveness to contraction stimuli; parturition does not proceed past 2nd stage; commonly seen with fetopelvic disproportion Term why might one decide to terminate pregnancy in cattle? Definition accidental breeding of heifers, or unwanted pregnancy in feedlot heifers Term What are the sources of progesterone in cattle and at what stages are they responsible for releasing it during pregnancy? Definition CL for the first 150-200 days, placental membranes for second portion Term How much progesterone is required to be in the blood in order to maintain pregnancy? Definition ~1ng/mL Term How can one cause abortion in cattle? Definition Prior to 150 days, 25 mg of PGF2a; after 150 days to cause abortion or induce parturition is to use dexamethasone (25 mg) and PGF2a (25 mg) Term How long after parturition is the point of retained placenta? Definition More than 12 hours post parturition Term What are the causes of retained placenta in cattle? Definition lack of proteolytic breakdown, which leaves the membranes intact; or insufficient myometrial contractions (commonly seen with dystocia) Term what are some of the major differences of parturition in horses as compared to cattle? Definition Horses have a much shorter stage 1, and especially stage 2; detachment of the fetus from the membranes is rapid and complete; dystocia is less prevalent in mares Term What is the difference in cervical dilation in horses as compared to cattle? Definition Horses cervices dilate in an active phase only Term which drug is used to induce parturition in mares? Definition Oxytocin Term What must be present in order for swine to have early recognition of pregnancy? Parturition? Definition at least 4 viable embryos; 2+ fetuses to release enough fetal cortisol Term which drugs are used to induce parturition in swine? Definition PGF2a and prostaglandin Term What is "ringwomb"? Definition Inability of cervix to dilate (sheep and goats) Term What does the ewe depend on for progesterone to maintain pregnancy? Definition CL up to day 60, after that placenta (ewe is therefor placental-dependent) Term what does the doe depend on for progesterone production to maintain pregnancy? Definition CL throughout pregnancy (therefor luteal dependent)