Browsing through some of the main AI company catalogues, you’d be forgiven for thinking we are in 2001 rather than 2021.

Pushing high-milk bulls seems to be the order of the day again. For example, the main dairy bull panel for Munster Bovine claims the bulls are suitable for herds targeting 500kg to 600kg of milk solids per cow. I thought we moved on from yield per cow as a metric of profit?

All but one of the 18 bulls on this panel are genomically selected. They have an average predicted transmitting ability (PTA) for milk of 181kg and an average EBI for maintenance of just €8.

In other words, these bulls will breed tall and milky cows. Their overall EBI is €273, with a balanced milk and fertility sub-index of €106 and €107 respectively.

These bulls will make up the bulk of the straws used by both Munster and Progressive Genetics AI technicians over the coming weeks as most are on the fresh semen panel.

Of the 18 bulls on the panel, 11 are from three sires. Among these is Diamond Anton FR2239, which topped the active bull list in 2018 with an EBI of €316 and is now at €205, with -€4 for maintenance and daughters producing 7,000l in third lactation at 4.35% fat and 3.58% protein.

Next is Oldcastletown Ronaldo FR2298. He had an EBI of €301 in 2018 and is now at €222. His daughters are doing similar yields to Anton.

Ballygown Albert is the sire of three bulls on the panel and is also on the panel himself with an EBI of €281. This bull doesn’t yet have enough daughters milking, so genomics is still making up a large part of his proof.

It’s difficult to see how, when daughter-proven, most of the bulls on this panel won’t end up with an EBI similar to their sires – that is €60 to €70 less than their current rankings. The daughters of these sires aren’t much good, so how likely is it that their sons will be much better? It’s worth remembering that half of an animal’s genetics come from its sire and half comes from its dam.


That doesn’t necessarily mean that each trait is made up of 50% of genes from the sire and 50% from the dam.

For some traits, the genes can be from just one parent or not from either parent, as the genes can mutate and act like an outcross.

It is these special genes present in what one could call superstar bulls that genomics helps to identify.

Considering most of the sires of these bulls were once superstars themselves and no longer are because they were ‘found out’ by their daughter proof, will the bulls on this year’s panel be any different?

The question farmers should be asking is whether these bulls will deliver long-term gains for their herd or a short-term gain in EBI in the youngstock? I say short term, because if the sire’s EBI drops, then the calf’s EBI will drop also.

Even if they do perform as per their current proof, is this the right cow for Irish farmers? I would say that they are completely the wrong animal for most Irish farmers and are even more wrong for over 4,500 Irish farmers since the Glanbia peak milk restrictions have been introduced.

These high-yielding bulls (+180kg PTA milk and +30kg PTA milk solids) will breed cows that have a very high and not a very persistent peak profile compared with bulls with a moderate PTA for milk volume and a high PTA for fat and protein percentage.

Páidí Kelly from TeamAg Consultancy says that high-milk-volume cows require approximately 1kg extra of dry matter feed intake per day just to produce the extra milk volume.

“Lactose, which is associated with milk volume, is essentially a sugar and takes a lot of energy to produce. When we look at two cows, each producing 500kg milk solids, but one through high volume and the other through high percentages, the high-percentage cow generates slightly higher milk sales because she is penalised less on A+B-C payment system.

“She would have lower feed costs and possibly better fertility because of her lower energy demands. That’s before we look at the maintenance sub-index and the extra costs associated with feeding bigger cows,” he said.

AI companies and farm advisers who are pushing for high-volume cows are doing a disservice to the farmer clients.

The correlation between profit and milk yield per cow is low at 0.15, meaning just 15% of the difference in profit between farms can be explained by milk solids yield per cow.

Costs of production account for 45% of the difference, so is a much more important thing to focus on when trying to improve profit.


The environmental impacts of these larger and high-volume cows is another matter.

Breeding higher-EBI animals is a key plank of the Teagasc greenhouse gas marginal abatement cost curve (MACC).

Improved fertility performance in high-EBI animals will mean fewer replacements are required, which is good from a cost and climate perspective.

However, the main reason why EBI features so highly in the MACC is that the same amount of milk can be produced from fewer cows.

Previous work done by Teagasc found a strong correlation between EBI and methane emissions per cow, but that’s not reflected in the MACC.

Cows don’t produce milk from fresh air. Higher-yielding cows produce more because they eat more and/or partition more of their feed intake towards production and less for other traits, such as maintenance, body condition score gain, etc.

There are finite resources on dairy farms in terms of land and how much feed can be produced.

Moving towards a high-yielding herd, as is being promoted by the use of these bulls, will mean farmers will either have to carry fewer cows or buy in more feed in order to keep the herd fully fed.

We know from experience in other countries that as milk yield per cow increases, it can be harder to fully feed cows at grass and extra meal and concentrate is required.

Dairy systems such as those demonstrated at UCD Lyons require 1.5t of meal per cow, while moderate production systems require about one-third of that per cow and are much easier to manage.

From a nitrates perspective, higher-yielding cows produce more nitrogen because they eat more feed. In Holland, Denmark and parts of the UK, cows have a different nitrate allowance based on their milk production – a reflection of the fact that higher-yielding and larger cows excrete more nitrogen.

The take-home message is that farmers need to carefully choose what AI bulls they will be using this spring. Leaving it to the AI company to decide is a potentially costly approach.

The risk is that they will push the straws they want to sell, rather than the straws that are right for your herd and farming system.

I’d encourage farmers to do their own research on bulls,. There is a huge amount of information available on the ICBF website. Not all superstar bulls will still be superstars after they get a daughter proof.

If using genomic bulls, pick bulls with a strong chance of success.

Calving date – Glanbia restrictions

Moving calving date in order to reduce peak milk penalties, such as those being enforced by Glanbia, would cost the Irish dairy industry €130m annually. This is according to the results of analysis conducted by Teagasc and looks at the impact of moving from a spring-calving system to a 50:50 split autumn- and spring-calving system.

Speaking on a Teagasc podcast, Laurence Shalloo said moving to a split calving system would increase processing utilisation from 62% to 70%, which should result in a milk price increase of 1.3c/l to 1.4c/l, but that costs of production on farms would increase by 3c/l, leading to a drop in farm profit of about 1.6c/l, equal to €130m across all milk produced in Ireland.

Shalloo advised farmers affected by the Glanbia rules to complete a cashflow forecast for the next few years based on different scenarios, such as using once-a-day milking or restricting supply at peak by feeding less meal.

A radical shift in calving date on some or all cows is not advised, as it is virtually impossible not to produce extra milk at peak. Furthermore, it will increase workload and reduce profitability.