HeatM8To cidr or not to cidr

Comparison Between cidred and non-cidred Cows

The graphic below shows an on-farm comparison between using cidrs for non-cycling cows as opposed to doing nothing with them.

Both the cidred and non-cidred cows had been calved for 42 days or more, so were early calving cows that had not had a pre-mating heat.

Points to Note;

1- Only 55% of the non-cidred cows were inseminated in the first three weeks as opposed to 100% of the cidred cows.

2- The NRR of both groups was the same at 37%. This correlates to the average NRR of first heats being ~ 40%, the difference is that the cidred cows as a group were inseminated on day 2 of mating and the average insem date for the non-cidered cows is day 19 of mating. A gain of 17 days for the cidr cows.

3- The cidr cows that returned were inseminated in week four of mating hence the six week in-calf rate of 69% as opposed to the six week in-calf rate of the non-cidr group of 51%.

4- A significant stat for the two groups are the empty rates with the cidr group having an empty rate of only 3% as opposed to the non-cidr group of 9%.

Summary

With the early use of cidrs on non-cycling cows there are significant gains to be had;

1- More DIM next year, 17 days in this case.

2- More and earlier born AI heifer calves leading to more options for selective culling of poorer performing cows.

3- A more mature group of heifers at mating leading to better conception rates.

4- A more mature group of heifers as first calvers leading to better lifetime production and fertility performance.

5- A significantly lower empty rate from the cidr group leading to more options for selective culling of poorer performing cows.

The best results from cidrs are when they are used early so that non-cycling cows are inseminated within the first week of mating.

Pre-mating heat detection is vital to be able to identify these early non-cycling cows.

Analysis of Late Calving Cows

% The graphic below shows an analysis of the mating performance of late calving cows.

The main points of interest are;

1- Only 9% SR in first three weeks of mating

2 - The mean date of first service was 31 days after the PSM (Planned Start of Mating) date

3- Only 22% six week in-calf rate

4- A 29% empty rate

Summary

As can be seen from the above analysis, the best return on investment is to identify and treat early calving non-cycling cows.

Late calving cows do not have time on their side to improve their chances of getting back in calf inside the block

By concentrating on the early calving cows there will be less late calving cows.

OAD vs cidr programme

Below are some stats derived from a trial comparing putting non-cycling cows on once-a-day milking versus treating them with a cidr programme

21 day SR;

Control group - 66%

OAD group - 77%

cidr group - 94%

3 week Incalf Rate;

Control group - 38%

OAD group - 42%

cidr group - 54%

Empty Rate;

Control group - 12%

OAD group - 14%

cidr group - 5%

Summary

As can be seen from the above analysis, the best return on investment is to identify and treat early calving non-cycling cows with a cidr programme.

It appears that putting cows on OAD milking does not have a significant impact on the fertility performance of non-cycling cows.

Non-Cycling Cow Treatment

The K.I.S.S Option or the Scan Option

The K.I.S.S. (Keep it Simple Stupid) Option;

1 Identify non-cycling cows 1 week prior to the PSM

2 cidr all non-cycling cows

3 Inseminate all cidred non-cycling cows on day 3 of mating.

The Scan Option;

1 Scan all non-cycling cows 1 week prior to the PSM to identify individual treatments required.

2 Write out a detailed plan for all the individual treatments (cidr, ovsync, estrumate, no treatment, etc.).

3 Leave instructions with the farmer to implement the appropriate treatment for each individual cow at the appropriate time on the appropriate day.

4 Inseminate the individual cows if and when they come in to heat.

Is there any difference in the outcomes of either method?

Well yes there is, these are the results from an on-farm situation when the non-cycling cows were scanned and individual treatments were used.

Non-cycling group size of 120 cows was scanned

98 cows were cidred

22 cows were left as they were considered to be cycling

Of those 22 cows 4 did not cycle in the first 21 days of mating

Of those 4 cows 1 was given estrumate and 3 were cidred

The average first insem date for this group of 22 "cycling cows" was 13 days later than the cidred group.

With the 3 later cidred cows being 28 days later than the cidred group

Costings

The extra time taken to scan all the cows to find 22 "cycling cows" as opposed to just cidring the whole group was approx 2.5 hrs

The cost of this extra time was equivalent to the cost of 22 extra cidrs for those "cycling cows".

The loss of 13 Days in Milk in the next year from these 22 cows was £1,776.00 (20ltrs x 30p x22cows)

Summary

The profitability of block calving lies in achieving a high 6 week in-calf rate

The 6 week in-calf rate is directly tied to the 3 week Submission Rate

Scanning and treating cows individually will lower the 3 week Submission Rate as seen in the example above.

The lost income from less DIM is significant.

The Scan option is more expensive, complicated and time consuming at an already busy time .

The simpler and more profitable option is to cidr all non-cycling cows 1 week prior to the PSM