Cycling and the Pregnant Cow Flashcards
(23 cards)
Natural Cover
Relies on detecting the signs of heat and allowing bulls to mate with receptive females
Heat Detection AI
Involves using trained personnel to detect signs of heat and then performing AI accordingly
Timed AI
Allows for insemination at predetermined times, based on hormonal treatments to control ovulation
What is the gestation period for cows?
9 months
When does weaning typically occur?
During the fall
When does first calving occur?
22-24m
How long is lactation?
305d
How long is the voluntary waiting period?
60d post-calving before breeding
How long is the cow estrus cycle?
21 d
Estrus 12-18h
How long is estrus to ovulation? Ovulation to fertilization?
Eā>O = 30h
O ā> F = 6h
How long is sperm transport and capacitation?
Transport: 8h
Capacitation: 6h
How do prostaglandins alter the reproductive cycle?
Induce estrus and synchronize breeding
How does progesterone alter the reproductive cycle?
Maintains pregnancy and can be utilized for synchronization
How do gonadotrophins alter the reproductive cycle?
Stimulate ovarian function and can enhance superovulation
Melengestrol Acetate
Oral progestogen for heifers to synchronize estrus
Controlled Internal Drug Release
Intravaginal progesterone insert left for 7 days to aid in synchronization
Lutalyse is injected to induce estrus and facilitate timed breeding
Ovsynch
Gonadotropins synchronize follicular development
PGF Programs
Estrous synchronization involving palpating the ovaries and injecting prostaglandins if the CL is present
When should implantation and nidation begin?
By day 20
When can a fetal membrane slip be detected?
30d
When can fetal palpation be performed?
35d
When can placentation be assessed?
80d
How is pregnancy diagnosed? When?
60d
Uterine horn enlargement
Membrane
Amniotic vesicle
Fetal heartbeat and visualization
Elevated progesterone
