Looking at some of the first calvers in Greenfield as they approach the end of the first lactation, you would have to question if this is the type of cow that will stay long-term on the farm. Some of the GZY-sired heifers look very leggy, big and Holstein-like compared with the mature cows on the farm.

Now, I say this, recognising that heifers are in their working clothes at this time of the year and it isn’t looks that puts milk solids in the tank. I also say this in the full knowledge that the milk solids and fertility performance of the herd as a whole has improved significantly over the last five years.

So let’s track back. The heifer in the picture above was sired by GZY (Gaddagh Cuddy Reeks) which was top of the EBI list when this heifer (1741) was born on 5 March 2015. She was bulled as a maiden heifer in May 2016, and calved down in spring 2017. The picture shows her this week (mid-November 2017) finishing her first lactation. So how has her sire performed?

The sire was picked as part of a team of bulls in 2014 (Table 1). No calving evaluation proof was available in 2014 when GZY was used so he was selected not knowing if she was hard calving or easy calving. After a few years in use, he now has a calving difficulty of 3.2, which means he is a hard calver. For me, AI sires need to be less than two for heifers and less than 2.5 calving difficulty for cows. Anything higher should not be considered irrespective of proof.

Anyway, let’s continue. By the time the calf landed (spring 2015) the GZY proof was still holding near €350 EBI. By 2016, the proof had fallen as the EBI figures dropped off in the rebalancing of the index and the sire proof dropped to €260 by December 2016. So while he had dropped effectively it was holding or slightly down as everything dropped on average by €70 EBI points. By 2017, when the heifer was calving down for the first time, the proof was down to €227. Now in the latest proof run (August 2017) the sire GZY is down to €191 as GZY now has over 1,100 daughters in his proof.

So what has happened the numbers behind the proof? The predicted milk proof numbers have changed considerably. Now that daughters are milking instead of a predicted proof of 80kg of milk volume and a combined 25kg of fat and protein, the proof is closer to -220kg of milk volume and only a combined 3kg of fat and protein. That’s a significant shift in milk numbers as the progeny proof takes shape. So it looks like this sire, having started out with a good looking milk proof, is not going to do much to bring more fat and protein into the bulk tank. The fact that 25% of our heifers are bred from GZY means we have lost opportunity for genetic gain with this sire. The lesson for the farm is while eight sires were used, we have ended up with two sires siring almost 50% of the heifers – GZY and JRE. JRE is another sire that has dropped off well in EBI. One lesson is very clear – not to use too much of any unproven (genomic) sire.

I started off suggesting that some of the first lactation animals look leggy. Let’s look at the GZY’s beef and maintenance sub-index. In the latest GZY proof, the beef is -€10 and the maintenace figure is €5, so what does this mean? The beef index ranks the economic value on culls and calves – the more negative the figure, the smaller the cow and the calf. The range in the most recent list was -€64 to €0. The -€64 sire is actually a Jersey sire (poor beefing characteristics). Yes, it is interesting to note that almost all of the Holsteins are breeding negative on beef traits so, as an index, ebi is making for smaller cows. GZY at -€10 means he is well towards the bigger end in terms of size.

Maintenance values

In the latest EBI run, the maintenance values range from €78 to -€10. The positive figures build into a better EBI, meaning highly positive is what you want. GZY maintenance is €5, so while positive he is very much near the bottom 5%. His beef and maintenance figures also suggest he will breed bigger cows, which seems to be true if you look at some of our heifers.

What are the implications?

When using genomic sires, we need to use a large number and use them evenly across the herd. We need calving evaluations, so as soon as the information is available we need to have that information to make informed decisions.

If we use too much of one sire or use a hard-calving sire the consequences and cost on the herd can be huge. It will be interesting to see how GZY heifers perform in the herd.

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Drying off started on Greenfield Farm