Heifer performance and extended grazing focus on Teagasc/Lakeland Demo Farms

Teagasc/Lakeland Dairies Joint Programme advisor, Sean Callan visits Killian Brennan in Co. Cavan who plans to extend grazing into November and prioritises reaching heifer target weights. Sean Callan also provides an update on milk and grassland performance across the monitor farms.

Farmer update – Killian Brennan

Killian Brennan’s herd is currently producing 1.89 kg MS/cow, up 0.07 kg MS/cow since the beginning of the month. While milk volume has eased, percentages have improved significantly, with butterfat at 6% and protein at 4.41%. Recent scanning recorded an 8% empty rate in the cows following a 10-week breeding season.

Killian is happy with his grass budget heading into October and aims to keep cows grazing into November. Heifers have been moved off the home farm to an out block, reducing demand and helping to extend the rotation. If growth rates fall significantly below demand, empty cows will be removed to prioritise grass for the in-calf cows. Weekly farm walks and the autumn grass budget on PastureBase will help guide these decisions.

Over the past two weeks, an out block of silage ground received 2 tonnes of lime per acre, while more silage ground received 2,000 gallons of slurry per acre. Parlour washings are also being applied to each paddock after grazing on the milking platform in advance of the closed period.

Weighing heifers

An important farm management task that is often overlooked is ensuring your replacement heifers are hitting their target weights. This will play a huge role in the productivity of your herd. Research has shown heifers not achieving target weight have poorer fertility and subsequent lifetime performance.

Target weights vary between herds, depending on the maintenance figures of the heifers themselves. However, in general, all dairy replacement heifers should be targeting an average daily gain of >0.7 kg/day. Achieving this daily gain should help ensure they hit their target weights. By using ICBF HerdPlus and some other farm software packages, farmers can identify the exact targets for their animals based on their individual maintenance figures.

Weighing the heifers is pointless unless something is changed to rectify any issues with heifers not reaching their targets. On Killian Brennan’s farm, the 2026-born heifers were weighed three times over the summer. 86% of the heifers were on or above target when they were last weighed in mid-August.

Following weighing, concentrate levels were adjusted accordingly. Prior to housing, they will be weighed again and split into three groups for targeted feeding to ensure they reach the required weights for the 2027 breeding season.

In-calf heifers will also be weighed prior to housing and split into two batches accordingly, ensuring adequate feed space and dry matter intake.

Group performance update

Milk solids performance remains good heading into October. Over the past three weeks, milk yield has dropped by 1.5 L/cow. However, protein has increased by 0.33% and fat by 0.34% to 4.00% protein and 5.00% butterfat, respectively, helping to maintain an impressive average production of 1.85 kg MS/cow. This represents a decrease of just 1% compared to three weeks ago. All Teagasc/Lakeland demo farmers have now completed their final scans, with an average empty rate of just 9% across their cows.

Table: Milk production on the Teagasc/Lakeland demo farms (week starting September 28, 2026)

Grass growth rates have eased slightly but remain good, averaging 60 kg DM/ha. Farmers have reduced demand accordingly to help build grass for the final rotations. Average farm cover has increased by 100 kg DM/ha to 992kg DM/ha, while cover per LU has increased by 49 kg DM to 323 kg DM/LU.

Table: Grassland performance on the Teagasc/Lakeland demo farms (week starting September 28, 2026)

Removing empty and underperforming cows from the herd, along with moving heifers off the milking platform, has helped farmers reduce demand and build grass cover. This leaves farms well positioned to extend the grazing season and, weather permitting, keep cows at grass into November.