Farm Ireland

Saturday 18 November 2017

Boosting cow numbers will pay off

John Donworth
John Donworth

John Donworth

By the end of the current milk quota regime, our quota size will have increased by just over 10pc. To enable us to fill all that milk quota, we need an additional 70,000 cows.

In the milk quota year just gone, we were under quota to the tune of 10pc. So, it will take a very big turnaround for us to not only fill our existing milk quota, but also the additional quota we are now receiving each April.

What's the key to increasing cow numbers on your farm? The answer is fairly straightforward: breed the replacement heifers to dairy AI sires. Currently, for every 100 dairy cows, we are breeding 26 replacement heifers. This is an improvement on the situation three to four years ago, when we were only breeding 21 heifers for every 100 cows.

Will 26 replacement heifers/100 cows allow us to find the extra 70,000 cows that the industry needs? No it will not. Approximately 10pc of the replacement heifers fail to make it to the milking parlour, so straight away one is working with a lower figure. Current replacement rates on farms are of the order of 25pc. This is not only due to high empty rates on farms, but also health issues such as a high somatic cell count.

So, if we accept that current numbers of heifers being reared on dairy farms are not sufficient to grow the national dairy herd, how many heifers should we be rearing per 100 cows to increase the size of the dairy herd to required levels?

The target for your farm should be to rear 40 replacement heifers/100 cows. So, how do we go from 26 heifers to 40 heifers? Well, the answer is fairy straightforward. Use enough dairy AI straws and begin with the replacement heifers.

In the EBI Discussion Group competition, the overall number of AI straws used on dairy heifers was 72 straws for every 100 cows. This is well below one straw/replacement heifer. So, if we are breeding Friesian AI on our dairy heifers, we are currently not using enough straws.

Current data suggests that to get 40 heifers from 100 cows, we need to use at least five straws per heifer. That's a total of 200 straws/100 cows, or two straws/cow. We can reduce that figure substantially if we use 1.3 straws on each of our maiden heifers.

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That's a total of 34 straws and it means some breeding heifers will be done twice with dairy AI sires. A tall order and is it too much work? If we are using 34 straws on the maiden heifers, that leaves us with 166 straws to be used on the 100 cows.

So, how many rounds of AI does that add up to? Let's say we submit 90 cows in the first three weeks. That's 90 straws used, and at a conception rate of 55pc that's 50 cows in calf at the end of three weeks.

If we again achieve a 90pc submission rate in the second three weeks of AI and again a 55pc conception rate on the remaining cows, a further 45 straws are used.

So, we have used a total of 169 straws after two rounds of AI on the dairy cows and also used 1.3 straws per breeding heifer. That should give us a total of 34 heifers/100 cows. To reach our target of using 200 straws, we not only need to use dairy AI straws in the third round of AI, but also some in the fourth round. That's using AI for 12 weeks of the breeding season.

Is it a step too far for dairy farmers in 2010? Certainly the rewards are there. Achieving high submission rates is also critically important.

In my calculations, I have used a 90pc submission rate. This leaves very little room for error and on the majority of our dairy farms, the figure is more likely to be close to 70pc, due to spread calving patterns. Immediately, one can see how using 200 straws in a herd of 100 cows plus breeding heifers is going to be a tall order.

However, you must set out your breeding objectives for the coming breeding season. And, if you have the area around the milking parlour to increase cow numbers, or you want to generate surplus stock sales, then it all starts with having a proper plan in place.

The secret weapon in all of this is the breeding heifer. She is genetically superior to her mother. She is also more fertile than her mother. One would expect a conception rate to first service of the order of 70pc. It would be a crying shame to use a beef bull on her, after all that.

Irish Independent