05 April 2025

AI results in the Derrypatrick herd

The Derrypatrick herd is an 80-cow suckler calf-to-beef research herd at Teagasc Grange. The spring-calving herd receives 100% artificial insemination (AI) and completes the breeding season over a nine-week period, Research Officer in Teagasc Grange, Dr. Peter Doyle tells us more.

A pre-breeding scan detects animals that are not cycling or have reproductive issues. Once breeding commences, the herd relies on three main heat detection methods:

Tail paint;
Vasectomised bull with a fitted chin ball;
Visual heat detection 3-4 times daily.

Any cow/heifer not inseminated after three weeks of breeding is placed on a synchronisation and fixed time AI programme (represents ~10 % of cows). When a cow is identified in heat, the AM/ PM rule is applied for AI.

Over the past five years, the following breeding results were achieved with the Derrypatrick cows:

68% conception rate to first service;
90% submitted for AI in the first three weeks of breeding;
90% pregnant after nine weeks of breeding.

Sire selection criteria

Derrypatrick is currently comparing Aberdeen Angus and Charolais AI sires that can achieve high ‘weight-for-age’ with the aim being to produce carcasses with ‘improved’ fat cover at young ages (20 months) in a grass-based system.

Aberdeen Angus and Charolais sires are selected for cows under the following criteria:

Calving difficulty: < 8 % (easy calving);
Carcass weight PTA: 5 star (high carcass weight);
Age to slaughter PTA: 4 and 5 star within or across breed (early slaughter age);
Carcass fat PTA: 1 and 2 star within or across breed (improved ‘fleshing’ ability);
Reliability of key traits: >70 % (proven bulls).

An example of some of the sires used to date include Aberdeen Angus: BJG, AA4089, AA4323, AA4638, AA4640, AA8559; and Charolais: CH2216, CH4251, CH4562, CH6271, CH6298, CH6310.

The above was adapted for use on Teagasc Daily from the article titled: ‘Artificial insemination in the suckler beef herd’, which was first published in the March-April edition of Today’s Farm.

Read the full ‘Artificial insemination in the suckler beef herd’ article here (PDF).