Don't leave problem cows to their own devices
It's nearly May 1 and getting cows and heifers in calf is the major priority on many dairy farms at present. Cows and heifers bred on May 1 will calve down on February 6 or 7, 2015.
A great number of you will have started breeding on April 20, with a calving date of January 25 next year. If you started on this date, you should have around 43pc of the cows bred by now. That's assuming your target submission rate is 90pc. In a 100-cow herd, if you want to submit 90 cows in 21 days, you must be breeding four to five cows per day, every day for 21 days. That will keep you very busy with heat detection work.
My definition of submission rate is a pretty strict one and it's the same one that ICBF use. All cows that calve up to the first 21 days of the breeding season are included in the figure. So a cow that calves on the 20th day of the breeding season is counted as being available for breeding.
Now we all know that you can't breed such a cow, but cows shouldn't be calving at this time in the first place. If you gave a farmer the choice of which definition they could use, they often only include cows calved 30 days before the breeding season starts. That's a very weak definition. Stick to the stricter version and if you are in a discussion group ensure theyuse the same.
Calving pattern is a pivotal driver of farm profitability and this is why emphasis is placed on achieving high submission rates in the first three weeks of the breeding season. How good is your heat detection work?
Studies show approximately 10-20pc of cows submitted for AI are actually not in heat. Low accuracy of heat detection will decrease conception rates to AI by 5-10pc. In addition to not going in calf, cows inseminated at the wrong time have a delayed interval to the subsequent AI. Another negative consequence of poor heat detection accuracy is that the risk of pregnancy loss is increased by 8pc for pregnant cows that are incorrectly re-inseminated.
Combine heat detection aids with at least three periods of observation in the field every day to improve accuracy. Remember, 70pc of cows show the greatest signs of heat between 9pm and 7am. That's why heat detection aids are a must.
What do you do with problem cows? We all know cows that calve early will resume cyclicity, be regularly displaying strong heat signs, have completed uterine recovery, passed peak milk production and finished losing body condition score by the time breeding season commences.
As a result of all these positives, early calving cows are likely to be submitted for AI during the first three weeks of the breeding season and have high fertility.
The general advice in the past was that problem cows, if left to their own devices, would eventually resume cyclicity. But doing nothing is not a solution for problem cows. Regardless of how they are bred, problem cows will have reduced conception rates. This is especially true of late calving cows subjected to a fixed time AI procedure. However, by going down this route, it ensures 100pc submission rates, advances the time of second AI in cows that do not conceive to first AI and increases the total number of pregnancies.
Dr Stephen Butler in Moorepark has recommended the following programme for treating problem cows (including late calvers):
* Day 1, am: Insert CIDR/PRID, give injection of GnRH;
* Day 7, am: Remove CIDR/ PRID and give a PG injection;
* Day 9.5, pm: Give a second GnRH injection;
* Day 10, am: Inseminate the cow.
This programme is suitable for normal healthy cows, at first or later services, as well as 'problem' cows (late calvers, anoestrous cows). Expect slightly lower conception rates for problem cows compared with healthy cows.
The injection given on Day 9.5 will usually be given at evening milking. For best results, the recommendation is that the cow is inseminated 16/18 hours after this injection.
- John Donworth is an area manager with Teagasc who is based in Kilmallock, Co Limerick.
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