AI Cheat Sheet
Why do we do it?
Control time of AI, no need to have bulls on the farm (SAFETY), target breeding for cooler seasons,
target milk production for higher prices, eliminate heat detection with TAI (timed AI), concentrate
breeding/calving labor, more uniform calf crop and for embryo transfer
When to do it?
At least 40 days after calving (time for uterine involution) and synchronization, average-above average
BCS, previous minimal calving difficulties, heifers at least 65% of adult body weight and normal repro
tracts (SCORE THEM!!!!!)
Can all places do it?
Yes, but…you need to consider…experience with heat detection (MUCH harder than it seems),
experience with AI/semen thawing, cattle moving facilities (chutes, etc.), equipment ok for AI?
Heat detection (not too easy)
Cows in standing heat for 14 hours, stand for about 8 hours (4-30 hours)
Decreases with heat, cold, lameness, strange people/animals around, space restraints, etc.
Need good footing, shade
Young cows, increased lactation stress, uterine infections, nutritional stress decrease signs
Heat check at least 2x per day at 11-13 hours apart (catch ideally 80% of heats)
Usually before milking in AM and after milking in PM (coolest times of the day)
Standing heat---cardinal sign of heat
Mounting or running away ARE NOT cardinal signs of heat (coming into or leaving heat)
Secondary signs----NOT reliable
Head laying, frequent urination, mucus discharge, red/swollen vulva, increased activity,
Roughened tailhead, dirty flanks, changes in behavior, decreased eating time
Only count cows in standing heat…breed 12 hours afterwards (some places 12 and 24 hours later)
AM/PM RULE
Heat detection aids: they’re AIDS only, shouldn’t be use alone (LAZY if done)
Falsely activated, crayons don’t work in rain, forget to take off (showing previous heat trigger)
Fertility rates higher in animals fully activated triggers AND standing heat…do both
Synchronization
Works better with cows than heifers
To hopefully get cows in same stage of cycle to concentrate labor, assist with AI (timing is
KEY…can’t get pregnant if the oocyte isn’t there) and timed AI (eliminates “need” for heat detection)
Hormone Review (KNOW THIS):
Progesterone: Pro-pregnancy, also high in luteal phase (from CL)
Products: CIDR (Controlled Internal Drug Release) or MGA (Melengesterol acetate,
feed additive)
Estrogen: high in estrus (no commercially available estrogen product allowed for use in food
animals)
GnRH: causes LH surge, heat, ovulation
Products: Cystorelin, Factrel, Fertagyl, Ovacyst (all IM, Cystorelin and Fertagyl also IV)
-also hCG product (LH-like activity), labeled for treatment of cystic ovaries: Chorulon
PGF2a (Prostaglandin): lyses the CL, brings cow into heat 2-5 days later IF CL was present
Products: Prostamate, Lutalyse, Estrumate, Insynch (all IM)
*It would not be a bad idea to familiarize yourself with the label for these drugs.
OvSynch, aka “7-2-1” (DO need to know protocols, but THINK)…35-45% pregnancy rates
Currently, normal cow pregnancy rates in Holsteins on dairies…about 17-19%
Reasons: bad AI techniques, missing heats, not breeding on heats, genetics
Day 0: GnRH---causes LH surge, ovulation-----------CL
Day 7: PGF2a----lyses CL from ovulation that occurred from 1st GnRH injection
Days 9: GnRH----ovulation
Day 10: heat detect, AI with AM/PM rule---cows in heat 2-5 days after PGF2a
Does this work for all cows? Probably not, as they need to have a follicle that is close to being
mature enough to ovulate. And if it did, we would have AMAZING fertility rates. Not a
perfect system!!!!
[Also for dairy protocols, add pre-synch and re-synch to basic ovsynch protocols. Co-synch is
Ovsynch with timed AI. Know all these protocols, plus all the protocols for beef. See website.]
What about adding progesterone into the mix?
MGA-PGF (don’t memorize, THINK)…70% pregnancy rates
Day 1-14: Feed MGA (mimics a CL, holds cows in a luteal phase of their cycle)
Day 14-20: stop feeding MGA (decrease in progesterone---heat…will see cows in heat)
Days 20-31: allow cows to cycle on their own (hopefully most are close in stage)
Day 31: PGF2a injection-----lyses CL from cow’s own cycle
Days 32-36: heat detect and breed (in heat 2-5 days after PGF2a), follow AM/PM Rule
The more hormones added, the more $$$$ it costs. Can be good, but need to think about the big
picture! Can you get away with using less hormones? What needs to happen to do so (think
heat detection, good AI technique, not in the summer time, etc.)
Now’s the time for TAI
By now, you should have gotten…HEAT DETECTION IS IMPORTANT AND DIFFICULT!!!!
To get around that, we can use protocols that avoid heat detection (good), but more $$$$$ (bad)
CIDR-CO-SYNCH (you should know what these hormones do by now)
Day 0: GnRH injection, Insert CIDR
Day 7: Remove CIDR, PGF2a
Day 9: GnRH, TAI (2.5 days/66 hours) after CIDR removed
In a study with 3-cycle Synch TAI programs (3 attempts/pregnancy), it cost $48.01 for each pregnancy
in hormones, labor, etc. Kind of expensive. So then think…is that more cost-effective for
having an open cow for a longer period of time due to poor heat detection? If so, then it’s good
for that farm
What about sexed semen?
Good for producing heifer calves (herd replacement, decrease dystocia rates, embryo production,
prove young dairy sires, etc.)
Good for producing bull calves (beef programs, dairy beef, embryo production, etc.)
“Made” in flow cytometer: very expensive equipment, few bulls, high cost
Fluorescent Activated Cell Sorting (FACS): 95-98% accurate, FEW LIVE SPERM
MoFlo: very efficient, 90% efficiency, cooled/frozen semen, 150-200 straws/day
Pregnancy rates DECREASE (probably due to more sperm handling/trauma), use less sperm ($$)
Angus heifers: non-sexed high conc. (98%), sexed low conc. (56%), sexed med. conc. (51%)
Works best if used in heifers (23 months of first calving >>> 30 months of first calving)
Requires well-managed herds, well-trained inseminators
Expected Rates: know normal/average and definitions
Pregnancy Rate
Conception Rate
Heat Detection Rate