Breeding

Olivia has selected AI bulls for this year’s breeding season. After some difficult calvings from a Belgian Blue and Charolais AI bull which resulted in 4 caesarean sections on the farm, this year’s bull choices will have a firm focus on calving difficulty.

The myostatin information is available for the heifers and some of the cows in the herd through ICBF (view profiles>genomics). Olivia has checked this information to identify if any heifers or cows have the myostatin mutation genes (Q204x or NT821) which results in a double muscled calf at birth, with harder calving difficulty. Two cows and 1 heifer are carrying one copy of either the Q204x or the NT821. Some of the cows have the F94L mutation which also results in doubled muscled calves, but without the increase in birth weight and calving difficulty. With this information, Olivia can choose carefully what bulls to match to each cow and heifer.

Some of the bulls she has selected this year can be seen in Figure 1 below.

Powerful Proper (LM7416) was picked to breed to maiden heifers. He has a heifer calving difficulty of 7.2% at 99% reliability and Olivia is happy that her heifers are well grown enough to calve him. She has used him in the past without any issues. He also delivers a carcass weight of 24.3kg, with a carcass conformation figure of 2.28 so should produce beefy, saleable cattle. Colour is also important to Olivia as she sells her weanlings live, and Powerful Proper will suit this. She doesn’t plan to keep any replacements off of him as he is low on daughter milk at 2.7kg.

Olivia has some cows in the herd that she does not want to keep replacements from. These will be bred to Charolais AI bull Orbi (CH6490). He has a cow calving difficulty figure of 4.4% at 99% reliability. His carcass weight figure is very good at 34.9kg and the carcass conformation is 1.98. Olivia is very happy that he will produced shapey, brown coloured weanlings for sale which is what her customers in the mart are looking for. He is very poor on daughter milk at -1.4kg so she won’t keep any replacements from him.

On the maternal side, she has selected Lis-na-Ri Gucci (SI4250). He has a cow calving difficulty figure of 3.4% at 99% reliability. His daughter milk is high at 7.6kg, which will add to Olivia’s current figure at 5.6kg. His daughter calving interval is -0.49 days which is an indication of fertility and he has a good carcass weight of 19.1kg. Olivia has picked her best cows to be bred to him with the aim of producing a heifer. Unfortunately sexed semen is not available for him.

Figure 1: Olivia’s bull selection for 2025

Figure 2: Calving difficulty & reliability is a key factor in Olivia’s breeding decisions this year

Grassland

Olivia measured grass on the farm on 9^th July. The grass covers were strong in some paddocks but as June was quite dry she was trying to hold covers in case rain didn’t come. After walking the farm and entering the data on to Pasturebase, she decided to cut 7 paddocks for silage although some of these had been planned for cutting already.

When the paddocks were taken out from the wedge as silage, the farm cover on 9^th July was 781 kg DM/ha with 17 days of grass ahead. The growth rate from 25^th June was 23 kg DM/ha/day and demand was at 46 kg DM/ha/day. This left Olivia back on target for the week.

She spread 1 bag of 18-0-15+3S/acre on some of the farm on 24^th June, and followed up with 0.5 bag protected urea/acre and FYM on the fields that were cut for silage.

Figure 3: Grass wedge on 9^th July 2025

Figure 4: Cows and calves were grazing heavier paddocks but grass was still leafy

Water Quality

Olivia hosted 5 discussion groups on her farm in June. Kieran Kenny, the local ASSAP advisor, was present to discuss water quality on Olivia’s farm. The PIP (pollution impact potential) maps for her farm show that the farm is most prone to nitrogen losses than phosphorus losses.

Figure 5: PIP maps for Olivia’s farm

Kieran explained how Irish dairy and beef farming systems are highly leaky in that only ~30% of nitrogen (N) fed to grazing animals is recovered in meat and milk — most of the rest is excreted as dung and urine.

He outlined  key practices to reduce Nitrogen loss which included;

1. Optimise Soil Fertility

• Ensure pH is at least 6.2 and phosphorus (P) and potassium (K) are at Index 3 or better
• Fields with balanced pH, P, and K retain ~63% of applied N — low-fertility fields retain just ~35%
• Liming acidic soils helps grass yields and improves use of both chemical fertiliser and slurry

2. Include Clover in Swards

• White or red clover reduces reliance on chemical N by fixing atmospheric nitrogen
• Nitrates rules require clover to be present in every grass seed mix

3. Use Protected Urea & Low-Emission Slurry Spreading (LESS)

• Protected urea cuts ammonia emissions and reduces N losses without impacting yield. It’s often the cheapest N-fertiliser per unit
• LESS slurry spreaders significantly reduce N volatilisation during slurry application

4. Fertiliser Nitrogen

• Apply early N (chemical or slurry) only when soil temp > 5–6 °C, grass cover > 400 kg DM/ha, no heavy rain forecast, and ground is dry
• When grass is growing it will take up nitrogen, the risk of losses increase if there is no growth

5. Grassland Measurement & Precision Planning

• Regularly record grass growth (e.g. via PastureBase Ireland)
• Draft detailed Nutrient Management Plans (NMPs) tying fertiliser inputs to actual demand and soil supply

6. Manage Grazing to Minimise Compaction or Poaching

• Grazing animals deposit most N as urine/dung patches; avoid grazing wet, low-drainage soils to reduce N₂O emissions

7. Buffer Strips and Riparian Zones

• Maintain no-spread buffer zones (e.g. 5–10 m for organic fertilisers, 2 m for chemical N) alongside watercourses or sloped ground to trap runoff

8. Graze Later in the Year

Extend the grazing season into autumn/early winter to reduce the amount of slurry stored and spread in riskier periods. Minimising stored slurry also reduces emissions