A series of farm walks organised by CAFRE dairy advisers, have focused on what farmers can do to cut out any waste linked to animals, fertiliser or feed on farms.

Addressing an event on the McConnell farm outside Armagh, Alan Hopps from CAFRE reiterated that improved efficiency will make the farm more profitable, while also reducing the carbon intensity of milk production.

He challenged farmers to look at their heifer-rearing enterprises and aim for a 25% replacement rate and calving in at 24 months.

“That is the ideal,” said Hopps, adding that the average replacement rate in CAFRE benchmarking is between 28% and 29%, while figures from APHIS suggest the average age at first calving is around 27 months.

Hopps presented data comparing the land required for youngstock in a 120-cow herd, where the replacement rate is 35% and heifers calve in at 30 months, versus a farm with a 25% replacement rate and 24-month calving.

On the first farm, there are 105 heifers at any one time, kept on 24.3ha, while on the second, there are 60 heifers on 12.4ha. In other words, an additional 11.9ha (29 acres) are required on the first farm to rear heifers – this land could be utilised for something else.

“Calve them early and keep your replacement rate down as much as possible,” said Hopps.

On the 88ha McConnell farm, run by Alan, along with his father, William, and son, James, 135 Holstein cows are milked through two robots on a fully contained system. The average age at first calving of heifers currently in milk is 24.3 months. Heifers going onto the robot average 605kg and at 150 days-in-milk this has increased to 650kg.

“The McConnells are doing a good job with the dairy heifers,” said Hopps.


When it comes to hitting targets for replacement rate, he said there are numerous factors involved, including ensuring vaccination protocols are followed and attention to detail around transition cow management. However, previous survey work by CAFRE identified poor fertility as the number one reason for cows to leave the herd, followed by mastitis and then lameness. In addition, 6% die or go off the farm at a cost, while 12% of first-lactation cows don’t get to a second lactation. Overall average lifetime yield on the survey farms was around 30,000l.

“We need to get lifetime yield closer to 40,000l,” said Hopps.

All AI work on the McConnell farm is done by a technician, with cows fitted with collars and scanning done once per month. One recent change has been to check pre-breeders 30 days post-calving, as opposed to 60 days.

Analysis of fertility performance over the winter shows a submission rate of 68%, a conception rate to sexed semen of 43% and a pregnancy rate of 29%.

“A typical figure is in the mid 20s. Over 30 is excellent,” suggested Hopps.


When it comes to bull selection, he encouraged farmers to look at fitness traits such as fertility and lifespan, as well as fat and protein, etc. He also pointed to analysis by CAFRE advisers, which showed that modern Holstein cows already have the genetic potential to produce high volumes of milk. A cow with a predicted transmitting ability (PTA) for milk of zero is still capable of producing 9,000l.

In the McConnell herd, the 2023 heifer calves have a PTA for milk of 340kg, which can potentially equate to over 11,000l, said Hopps.

The McConnell herd is milked through two robots.

Challenge to increase milk from forage

At present, on the McConnell farm there are 122 cows on the two robots, averaging 30.6l per cow at 145 days-in-milk. It means there is around 7% to 8% free time on the robots.

“We have had the robots since 2011 – we try to keep them maxed out the best we can,” confirmed Alan McConnell.

The majority of cows are calving from August through to March, although some heifers have been held back to calve at the end of June 2024, to maintain milk output over the summer period.

Cows are fed a total mixed ration (TMR) of first-cut silage plus whole crop rye and 3.5kg of a blend. They are then fed a maximum of 8kg of concentrate in the robot and topped up to yield via out-of-parlour feeders.

The rolling annual average yield stands at 9,010l from 3.8t of concentrate fed per cow, leaving a milk from forage (MFF) figure at 574l.

“The MFF is modest. My challenge to Alan is to double that, which will lower the amount of concentrate fed. If Alan could get 6kg more silage into the diet, he could save 2kg per cow, per day,” suggested CAFRE dairy adviser Michael Garvey. One of the potential ways to achieve that is to add on more feed space. The main cow house on the farm has five rows of cubicles down one side and three down the other. In total, there is 120ft of feed space for 122 cows. The McConnells intend to add another 30ft in the coming weeks by removing a wall. At present, the TMR is pushed up three to four times per day.

Cow diet

The other issue raised by Michael Garvey relates to the inclusion of whole crop rye in the cow diet. While there is plenty of anecdotal evidence from local farms that including a second forage helps drive intakes, which ultimately has health benefits for cows in high input systems, analysis of rye indicates it is not a high feed value crop.

First-cut silage on the McConnell farm is excellent, with ME at 11.9MJ/kg and a D-value of 74.4. The whole crop rye has a ME value of just 10MJ/kg.

“The rye is diluting down the energy from the first cut. Alan is not getting the value out of the first cut,” suggested Garvey.

But the alternatives to rye might be fairly limited. Alan McConnell points out that his farm is too high for maize and he has found whole crop wheat more challenging to grow, especially given it is planted out later in the year.

“I can get the rye in on 20 September. It is sprayed once, just gets slurry and is cut in the second week of July,” he said.