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17 Cards in this Set
- Front
- Back
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What is the traditional definition of cystic ovarian syndrome?
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Follicular (fluid-filled) structure >2.5cm, persisting >10d in the absence of a CL
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What is the functional definition of COS?
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Anovulatory follicle >/= 17mm, absence of CL inducing altered cyclicity, with ovarian follicular waves continuing and dominant follicles persisting ~13 days
Lack of uterine tone! NO ovulation, NO LH surge |
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What are possible outcomes of COS?
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Cyst persists: 10-20%
Cyst turnover: 51-56% Spontaneous recovery: 20-60% |
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What are predisposing factors of COS?
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2nd and greater lactation
Early lactation High milk yield Summer calving Fat cows/ketosis Stress (Cortisol decreases GnRH, decreases LH) Health problems (uterine infection, lameness) |
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What level of progesterone indicates a cystic follicle?
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< or = to 1ng/mL
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What is a luteinized follicle?
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Non-pathologic!
Follicle growth- ovulation- release ovum- lutealized- has fluid in the center during transition between CH and CL |
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What does it mean if the follicle has an ovulation papilla?
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HAS OVULATED! NOT a luteal cyst, may be cystic CL
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How do you diagnose COS?
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On rectal palpation: follicle that is ovulation size or bigger (>17mm)
Lack of uterine Tone, Lack of CL Nymphomania persisting: sterility hump, increased relaxin U/s: Fluid filled anechoic structure within ovary homogenous texture to the uterus evaluate thickness of follicle wall/degree of luteinization V. useful for distinguishing cyst from a soft CL with no palpable papilla CL=OVULATION! |
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Pathogenesis of COS?
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Failure of estradiol to stimulate release of GnRH surge from the hypothalamus-- NO LH preovulatory surge, therefore the ovulation sized follicle is in a low progesterone environment- growth continues
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What happens when you can't rest the hypothalamus with COS?
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Cysts persist due to no progesterone exposure
Decreased expression of Estrogen receptor alpha |
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What is Estrogen receptor alpha responsible for/ related to?
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1. Initiation of GnRH signal
2. Progesterone up-regulates ER alpha 3. ERalpha becomes downregulated by Estrogen exposure |
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What causes Decreased progesterone in COS?
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1. Short luteal phase: CL develops but doesn't persist
2. Increased progesterone metabolism: High production dairy cattle eat a lot Increases hepatic blood flow Increases efficiency at conjugating/eliminating steroid Decreases progesterone and estrogen Decreases hypothalamus priming and increases FSH, leading to more follicles (mult ovulations/twins) |
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What is the goal of COS treatment?
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Conception
Increasing circulating progesterone (exposure to progesterone for 7 days restores responsiveness to estradiol) Induce ovulation of a follicle and CL formation |
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What is a successful COS treatment defined as?
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Regression followed by ovulation and formation of a normal CL within 15 days
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What is the best treatment for COS?
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OVSYNCH!
1. GnRH (new follicles develop, luteinization) 2. 7 days later PGF2a (luteolysis) 3. 48 hours later GnRH (ovulation) 4. 16 hours later, timed AI |
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How do you use a CIDR to treat COS?
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Add progesterone via a CIDR for 7d, and PGF at removal then AI,
Or Ovsynch +CIDR increases pregnancy rates |
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How do you prevent COS?
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Decrease incidence of nutritional and metabolic disorders
Genetic selection Decrease stress- good transition cow management |
