Term
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Definition
- Approx. 14-18 hours (short)
- LH peak in the middle of estrus
- Ovulation 12-16 hrs after end of estrus
- Reproductive tract under E2 influence-->strong myometrial tone-->uterus is firm and coiled
- Cervical mucus
- Pheromone in mucus attracts bull
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Term
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Definition
- E2 acts on CNS and causes estrual behavior
- As the cow enters estrus- agressive and mounts other cows
- Lordosis
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Term
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Definition
- Phase of ovulation and early CL formation (approx. 2 days)
- uterus loses tone
- mucus secretion decreases
- Approx. 30% of cows exhibit pseudomenstruation
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Term
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Definition
- Phase of functional CL and P4 production
- Approx. 15 days
- CL persists until about day 16 when PGF-2alpha is produced by the uterus
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Term
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Definition
- Phase of follicular growth and E2 production
- Approx. 4 days
- E2 acts on CNS, uterus, cervix and vagina
- E2 oeaks during this time and induces increased blood supply to reproductive tract causing edema and onset of cervical/vaginal secretions
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Term
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Definition
- Lactationally influenced anestrus
- Last approx. 7 weeks (can be longer)
- Dairy tend to have shorter anestrus than beef
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Term
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Definition
- Ovulation w/o estrus
- first estrus following postpartum anestrus is often silent (about 50%)
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Term
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Definition
- Sterile heifer born with bull co-twin
- Anastomosis occurs in >90% of twin pregnancies
- PGC cross over between the twins
- Freemartin will possess cells having XY and XX genotypes
- Determined by blood test
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Term
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Definition
| Fusion of blood vessels between adjacent placentas |
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Term
| Fertility and Frequency of Freemartin |
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Definition
- 90-95% of heifers born with bull co-twin
- bull twin usually fertile
- Infertility is caused by incompletely developed and masculinized reproductive tract
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