Available tools for synchronization of estrus
records, heat detection, synchronization aids, AI, advanced reproductive technologies
Breeding methods
natural service, artificial
Natural service
no heat checks, using bull to breed, animals get covered and secure pregnancy better
Artificial breeding
increased breeding for specific traits, greater genetic base to choose from, more work, reduced efficiency at checking for heats and placing semen
AI brings genetics improvement to the ____
herd
AI brings genetic improvement to the ____
herd
Benefits of synchronization
more timely first service, group females for parturition, more uniform weaning weights, reduced time required for detection of estrus, eliminate the need for detection of estrus with TAI, target anestrus animals
Prostaglandin
regress CL
GnRH
stimulate release of FSH and LH, induce ovulation, bypass need for estradiol
Progesterone
negative feedback to GnRH, keeps the animals from going into heat
Prostaglandin uses
synchronization of estrus, treatment of silent estrus, treatment of uterine infection, treatment of cystic ovaries, abortion of feedlot heifers, controls the CL and cause uterine contractions
______ CL does not respond to prostaglandin while _____ CL does to respond to prostaglandin because of less luteal tissue
presistent, cystic
Two available administration methods of progestogens
MGA, CIDR
MGA
orally active feed additive, minimum of 14 days to be effective
CIDR
vaginal insert, minimum of 5-7 days to be affective, progesterone absorbed through vaginal lining
Progesterone uses
induce cycling, suppress GnRH expression, synchronization of ovulation by removing progesterone source, suppress GnRH
Cows have ___ follicular waves
2
Heifers have ___ follicular waves
3
GnRH uses
treatment of follicular cysts, synchronize ovulation, initiate a new follicular wave, given at the beginning or end of cycle, stimulates LH release which controls follicular waves
Heat detection 6-10 hours before estrus
vocal, nervous/restless, smells other cows, rides cows
Heat detection of estrus
nervous/restless, mucous discharge, stands to be ridden, rides other congregates
Main sign that a cow is actually in heat
stands to be ridden
Heat detection of estrus up to 10 hours late
mucous discharge
When most cows express estrus
12 am - 6 am; coolest part of the night
Secondary estrus detection methods
records, chin ball markers, bovine beacon, kamar, estrus alert, chalks and paints
Synchronization rate
percent of females detected in estrus compared to the total number synchronized
Conception rate
percent of females pregnant compared to the number of females inseminated
Pregnancy rate
percent of females pregnant compared to the total number synchronized
Used to get an overall idea of how good the synchronization program is
pregnancy rate
Estrous synch
synchronizing the expression of estrus, requires heat detection, higher PR/higher labor, inseminator confidence
Ovulation synch
synchronizing the time when ovulation will occur, lower PR/ lower labor, often will not show signs of estrus, efficient in problem animals
Prostaglandin problems
cost effective, easy to use, high estrous response, only effective at days 5-16, requires an animal to be cycling, requires extensive estrus detection
GnRH and prostaglandin programs
improves tightness of synchronization, increases PR when using TAI, can reduce the need for estrus detection, expensive synch aid, more intensive synchronization program
GnRH is always
coupled
Progestogen programs
induce cyclicity in anestrus animals, can jump start the estrous cycle in prepubertal heifers, higher estrus response than prostaglandin alone, MGA reduces handling time, CIDRs are expensive, requires other synch aids
GnRH treatment _____ following progesterone treatment is most effective
1-3 days
Common causes of failure of synchronization programs
management factors not up to par, not using the correct system, not administering injections properly, unrealistic expectations