Over the past five years with field data using different protocols TAI in dairy herds realized that ovsynch and pre-synch walks very well with protocols similar to those sold in our country (Brazil) rates. And on farms where there is electronic system for detection of estrus or the use of paint on the tail had higher pregnancy rates than with the use of TAI with P4/E2.
This is just an observation of field data with approximately 10 000 inseminations.
Where to p4 / E2 pregnancy rate is 35%, Ovsynch (24%) Pre-Synch (33%) and PGF with estrus detection (40%). Average of all farms assisted 90% of cows are heat after 3 applications of PGF.
Chapter Fertility of fixed-time protocols in dairy cattle Evolution ...
40% is the rate of conception of cows that show heat after application of a dose of PGF in the forty-fifth day post partum. Although still low, I consider better than TAI.
I always like to compare fertility of yearling heifers with that of cows on the same farm, especially if heifers are inseminated after natural estrus. Heifers should have the highest fertility and will provide clues to problems with insemination techniques, semen handling, vaccination programs and general nutrition. Any difference between cows and heifers is then associated with transition cow health, energy balance, heat detection, poor-responders to TAI and similar environmental issues. One can also look at difference between heifers and cows during warm seasons to see the impact of heat stress and its potential carry-over into cooler seasons. Monitoring BCS during 3 weeks after calving can be useful in predicting conception rate at 70-90 days postpartum in lactating cows.
The biggest things to think about for cows is this:
How hard are they milking?
-With all the energy requirements for a dairy cow to produce as much milk as they have been genetically selected for this takes away energy for reproductive cycles/fetal calf growth.
What does the ration look like?
-How is the ration that you are feeding the cows? are you component feeding or using a TMR ration? how are the forages you are using? This plays a huge role in the reproductive cycle for the cows.
What heat detection system are you using?
-Electronic heat detection systems are great for large dairies. But heat detection using your eyes and mind are the best. Using tools such as computer systems for milk production (low milk production for 24-36 hours makes you think of cow in heat), last charted breeding date. Tail paint is a great way to help the herdsman. Having a very dedicated herdsman is the make or break factor in heat detection. if you have a lazy or uninformed herdsman you might as well shoot the semen on their back because it will allow for poor conception/pregnancy rates.
What FTAI protocol are we using?
-Some protocols use easy simplified schedules for that specific farmer/researcher. using presynch protocols help start cows off after 45-60 days post-calving. it also works great for heifers.
In heifers:
-All the aforementioned things play a factor. I would also say a simple PGF-2 alpha shot at 12-14 months old (depending on the farms first calving desires) then allowing for 1-2 cycles then breeding off a natural heat using sexed semen (if able to afford) will help improve conception/pregnancy rates.
Just remember its not a FTAI protocol that will be a cure-all. Dairy production all plays together. Keep it simple!
Jacob, I think you probably meant a prostaglandin F2a injecton at 12-14 months of age rather than an injection of progesterone. Right?
Jack, Yes I'm sorry I had all these thoughts and was a bit ahead of my hands! I got it fixed!
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