Using teams of high-EBI bulls this springtime

This is especially relevant as recent analysis by ICBF has indicated that while farmers use on average 6.7 dairy AI bulls during their breeding season, 41% of the resultant calves are just to one dairy AI bull, which points to significant overuse of a single AI bull on many farms.

Reports to herd owner

The analysis was a part of a recent report posted to 10,338 dairy herd owners, which provided them with some key statistics relating to the breeding performance of their herd in 2015 and 2016. An example of one such report, together with the relevant national statistics, is given in Table 1.

From this report, one can see that this herd owner had 77 dairy heifer calves born on his farm 2016, all of which were bred from dairy AI sires. This is in comparison with the national average figures of 29 dairy heifers, of which 81% were AI bred. The relevant target for this statistic (percentage of dairy heifer calves that are AI bred) is 100%.

Number of bulls used

Looking at the number of bulls used on this farm indicates that the herd owner in question used 13 different dairy AI bulls on the farm in 2015, which is well above the national statistic of 6.7. Both of these figures are very good and highlight that when using dairy AI, herd owners are “spreading the risk” associated with using AI bulls that are not 100% proven and instead are using teams of AI bulls. This is an excellent statistic to report from a farmer and industry perspective, with both figures being above or in-line with the national target of 7+ AI sires being used.

Overuse of just one bull

However, what is a major concern from the analysis is the overuse of one bull, with 41% of all AI bred heifer calves being to just one bull on the 10,338 herds analysed. This is also relevant for the herd owner reviewed in Table 1, where 25% of his resultant calves were to just one bull, which is above the target of 20% maximum to any one sire.

Why is this figure so important?

The recent EBI evaluations have clearly highlighted that individual AI bulls can drop by as much as €120 as more data comes on stream. However, the average of a team of bulls is much less likely to move, as the risk of one bull dropping significantly is balanced off by the possibility of another bull in the team dropping by much less, or even increasing in EBI value, as more data accumulates.

So the key recommendation from an ICBF and Teagasc perspective is that herd owners use teams of high EBI AI bulls equally on their herds this spring. They should aim for a minimum of seven bulls, with a maximum usage to any one bull of 20% of their semen allocation. This way, the impact of any one bull dropping significantly in EBI will be minimal, in terms of its impact on the average EBI of your calf crop to be born next spring.

Table 1: Example report for a herd-owner.

Dairy Females born on your farm in 2016	Your Herd	National Average*	Target
1. Total number of female calves	77	29	n/a
2. Percentage AI bred (actual number is in brackets)	100% (77)	81% (23)	100%
3. Number of dairy AI bulls used as part of your team	13	6.7	7+
4. Percentage AI bred calves born from the most heavily used AI bull (actual number born is in brackets)	25% (19)	41% (10)	Max. 20%

* National average statistics are based on 10,338 herds & 302,684 dairy females calves born in 2016.

At this stage some 1,533 herds have run ICBF Sire Advice program, which helps to identify and then allocate AI bulls for use on a given herd. Latest statistics from these herds indicates that 78% of the sires being used by these herd-owners this spring are young high-EBI GS bulls, 15% are daughter proven bulls and the remaining 7% are to foreign bulls. This highlights that despite the recent concerns regarding the EBI adjustments (especially for the young GS sires), herd owners are still using these bulls as the main core to their breeding programmes this spring. We will be keeping an eye on this statistic over the coming weeks.

You just can’t go past the young Genomic bulls

Cows & heifers

Milking 310 cows with additional 75 replacement heifers for breeding this Spring. Cows are currently yielding 25 litres, with 2 kg MS/day.

Latest ICBF stats re: teams of bulls

126 heifers calves born in 2016, 87% of which were AI bred, from 14 different AI bulls and with a max of 15% to one bull.

GS or DP bulls and why?

Even though the young GS (Genomically Selected) bulls have dropped a bit, they are still just too far ahead of the Daughter Proven bulls (DP). You can’t go past them. Key is to use them as a team. This year I will use a team of 13 bulls. Last year I used 14. Maximum use of any one bull will be 40 straws this year, which will be 10% of my total straw usage.

Bulls being used in spring 2017

13 AI bulls selected. Main bulls are Pamela, Candy, Sebastian, Rudoplh and Leister. Average weighted EBI of bull team from ICBF Sire Advice is €251.

Breeding programme plan

I’ll be starting AI on 1 May, and plan to use dairy AI for five weeks, then beef AI for another four weeks, then sweeper bulls. I’m using a local AI technician, based on AI’ing once a day. I find it works really well. For the past six years I’ve been running at around 5% empty at the end of the breeding season, which is a great endorsement of the impact that EBI has had on Irish dairy farms.