Oliver O’Hara January/February Update 2026

Breeding

Lambing started in mid-March with the commercial ewes and is progressing well.

Figure 1: Ewe with two lambs in lambing pen

Breeding is almost finished for the cows and heifers that will be bred indoors. They were all AI’d and to Limousin bulls – Keltic Rembrandt (LM8259), Plumtree Fantastic (S1278), Loyal (LM4184), Tomschoice Scorpion (LM1109) and Powerful Proper (LM7416).

Seven heifers were synchronised and bred at the rented shed. They were fixed time AI’d and are due to be scanned in the next month. Two repeated and were served again.

The rest of the cows left to calve will be turned out with the Limousin stock bull on the out farm in Sligo when weather allows.

Figure 2: Some of this year’s calves with cows in the background

On analysis of the stock bulls used, daughter milk was quite low for trying to breed replacement heifers in the herd, ranging from -4.4kg to 4.4kg. LM1109 is the highest at 4.4kg, which is higher than the herd average of 3.5kg so his daughters would help to improve the milk in the herd. The daughter calving interval, which is an indication from fertility ranges from -1.75 days to +2.69 days. The cow calving difficulty is less than 5.1% on all bulls, whereas the heifer calving difficulty ranges from 7.6% to 10.7%. The carcass weight is high and ranges from 22.1kg to 35.8kg which would deliver big cows if kept for replacements. The traits are outlined in Table 1 below.

Table 1: Eurostar traits for AI bulls and stock bulls used to date (November 2025 evaluation, source: ICBF)

If Oliver wanted to improve the daughter milk in the herd, there are proven AI bulls available that could help with this. On a search on ICBF of Limousin bulls on the active bull list with over 7kg of daughter milk there are 7 available as outlined in Table 2; Eylau (LM6601), Ampertaine Metric (LM5764), Nebbiolo (LM3713), Erebos (LM6172), Day (LM2190), Jaurel (LM8715) and Bavardage (AGB).

However the other traits of daughter calving interval and carcass weight also have to be taken into account. The carcass weight ranges from 14.5kg to 36.2kg. The average carcass weight for Oliver’s herd is already 25kg so breeding high carcass cows with high carcass bulls will produce big cows going forward. On the other side, breeding lower carcass cows to higher carcass cows will help to produce a balanced replacement at 18-20kg carcass weight, and still produce a good bull calf too. The daughter calving interval for the herd is +1.01 days and the only bull that will help improve this is LM6601 who has a daughter calving interval of 0 days. AGB has a figure of +8.1 days so he would disimprove fertility in the herd.

The key is to match the bulls to each heifer or cows and aim to breed a replacement with 18-20 kg for carcass weight, 8kg for daughter milk and a negative figure for daughter calving interval (the lower the better).

Table 2: Eurostar traits for AI bulls with daughter milk figures over 6kg (November 2025 evaluation, source: ICBF)

Animal Health

Oliver plans to vaccinate all his breeding cattle and sheep against bluetongue this year. It’s a viral disease affecting cattle and sheep, but it does not affect humans and poses no food safety risk.

It can be transferred 3 different ways:

1. Midge transmission – the main route of infection. A midge bites an infected animal and the virus replicated. After 4-20 days the midge is capable of infecting another animal.
2. Semen transmission – infected bulls can spread the virus through semen.
3. Transplacental transmission – the virus can pass from the dam to the foetus.

The risk period is from April–November  when temperatures >12–15°C allow virus replication in midges.

Symptoms include:

• Fever, inappetence, drop in milk yield
• Reddening of mucous membranes
• Sores on nose, gums, dental pads
• Swelling of face, lips, tongue (“bluetongue”)
• Breathing difficulties, drooling
• Discharge from eyes/nose
• Lameness
• Reproductive signs: abortions, empty cows/ewes, weak or malformed offspring
• Note: Sheep often show severe signs; cattle and goats may appear healthy but still suffer fertility losses

The highest priority for vaccination are breeding stock, i.e. cows, breeding heifers, ewes and rams. The program for cattle is: 2 doses, 3 weeks apart and immunity develops ~3 weeks after second dose. It should be done at least 6 weeks before the breeding season or risk period, and can be given to stock that are already in calf. Each shot will cost €4-4.5o per animal, albeit that sheep only require one shot for protection.

Figure 3: Breeding stock will be the highest priority for the bluetongue vaccine

Greenhouse Gas Emissions

Oliver updated his carbon footprint for the year in conjunction with local climate advisor, Aaron McBrien. His data was entered onto the Bord Bia sustainability survey which allowed him to generate a carbon footprint. The carbon footprint on the farm was 16.54 kg CO2e per kg of live weight gain, which is high for a beef farm. It increased from 13.86 kg CO2e per kg of live weight in 2024 – mainly due to less kg of beef produced on the farm and an increase in fertiliser usage due to extra silage made.

Actions that Oliver could take to reduce this going forward are:

• Reducing chemical nitrogen usage by 10% through liming, spreading fertiliser when grass growth is high and getting more value from his slurry by spreading more in spring.
• Spreading all straight nitrogen as protected urea.
• Spreading 70% of slurry in spring and 30% in summer with none in autumn.
• Turning out weanlings before the end of March and cows by early April where weather allows.
• Calving all heifers at 22-26 months of age.
• Improving the maternal traits of the herd so that more weight gain is coming from milk.
• Maintaining the soil pH which is excellent on the farm.
• Continuing to follow a herd health plan to reduce the risk of disease or parasite burdens.