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Update on Hill Top Dairy
TIPS ON IMPROVING PREGNANCY
RATES WITH OVSYNCH
The OvSynch program has been used for several years and we are slowly learning how to achieve higher pregnancy rates. The OvSynch program includes giving GnRH at -10 days, prostaglandins (PG) at -3 days, GnRH at -1day and A.I. at 0 day. Now we know that we can expect pregnancy rates of 30 to 40% in dairy cows using this timed AI program.
Some dairymen like this program. It gives them a 30 to 40% "head start" on getting the herd pregnant and it only requires 10 days. What is happening in Japan? What percent of dairymen use OvSynch? I am happy that we have the OvSynch program but wish we could get higher pregnancy rates. Let me describe our breeding program and how we use OvSynch at Hill Top Dairy. We watch cows for estrus starting at 50 to 60 days after calving. We AI all cows observed in estrus. All cows, not observed in estrus by day 80, are injected with PG. If we do not detect them in estrus by day 94, we inject a second dose of PG. All cows that are not bred by day 108 are started on the OvSynch program. We also use OvSynch on two other groups of cows: 1) cows diagnosed open on pregnancy check day and 2) some of our cows diagnosed with cystic ovaries.
ur pregnancy results using OvSynch on these 3 groups of cows range form 30 to 43%. I sort of like the program because it only takes 10 days to get one-third of these three problem groups pregnant. We might get slightly higher pregnancy rates if we used OvSynch on all first service cows
Here are four suggestions on how to improve pregnancy rates with OvSynch:
| 1) | Use the Presynch program plus OvSynch. Presynch means giving two PG injections at -36 days and -22 days followed by the OvSynch program (GnRH at -10 day, PG at -3 days, GnRH at -1 day and AI at 0 day). This program increased pregnancy rates in dairy cows by 14% in a Florida study and by 12% in Kansas when compared to OvSynch alone. These results were obtained on over 500 cows in both of the above states. Presynch works because the two PG injections causes more cows to be in between days 5 to 12 of the estrous cycle. This means we get closer synchrony of ovulation with the OvSynch program. So Presynch works but it requires more injections of hormone, more time, and more labor. |
| 2) | Insemination of cows observed in firm standing estrus always gives higher pregnancy rates than timed AI. Nearly 25% of cows will express estrus other than when they are assigned to be inseminated. So always tell your clients to watch for estrus and AI all cows that express estrus. We always do this at Hill Top and it gives us a higher pregnancy rate. |
| 3) | Always use small needles and syringes when injecting GnRH and PG. Both hormones are in saline and can easily run out of the injection site if large needles are used. We should use a 3 cc. syringe for GnRH and Estrumate and a 6 cc. syringe for Lutalyse. Use a 20 gauge needle that is 1 1/2 to 2 inches long for both hormones and inject deep in the muscle. |
| 4) | Do not load up more than 2 A.I. guns at one time. Research clearly shows that pregnancy rates drop when more than 2 A.I. guns are loaded per technician. The semen thawing operation should be close to the cows. |
The above tips should increase OvSynch pregnancy rates. We must pay attention to details, and handle the cows with care. This always improves our success with A.I.
(Part of this article was published in Hoard's Dairyman, Jan.10,2001, Page 21)
News Letter from Dr. Whitmore, September No.2 2001