In pasture-based systems of milk production, the three-week breeding submission rate target is 90%, which is critical in order to achieve a six-week calving rate of 90%.

Nationally only 65% of cows and heifers calve during the first six weeks of the calving season; ideally this should be at 90%. Doing so facilitates long lactations and high levels of milk production.

While nationally this has improved over the past five years, Teagasc’s analysis shows that the effect on profitability is still substantial. On average the national cost is €206 less profit per cow per lactation.

Maximising three-week in-calf rate

Between three and five weeks before the start of breeding, body condition score the whole herd and identify cows with a score of 2.5 or less.

They should be kept on once-a-day (OAD) milking until three weeks after they have been bred.

The second step is to record the heats of cows before breeding starts using tail paint to identify cows that are not cycling. They should be scanned and non-cycling cows synchronised to breed them on mating start date.

Cows that are less than 30 days calved are not suitable for synchronisation and should be left until a group is put together and a second non-cycling group synchronised later on.

Record dates of insemination on the Irish Cattle Breeding Federation (ICBF) HerdPlus, either manually or via the AI technician handhelds. This will allow you to run fertility reports.

Targets are 30% inseminated in week one; 60% submitted by the end of week two; and 90% submitted by the end of week three.

Two factors that can reduce three-week in-calf rate:
  • Low submission rate – because cows are not cycling or because of poor heat detection;
  • Low conception rate – because of the presence of uterine infection.

Non-cycling cows that are calved 30 days or more but not cycling should be synchronised to induce cyclicity.

Also Read: Breeding management of late-calving dairy cows

Poor heat detection

Cows come into heat at all times of the day. On average however they are only on heat for eight hours with slightly more than half of them standing for eight hours or less.

This makes them really difficult to identify in heat. Teagasc research has also found that late-calving cows will be more difficult to spot in heat as they tend to have shorter duration of standing heat and because they come into heat later in the breeding season (when the bulling group will be smaller).

As a result Teagasc recommends two actions:
  • Three periods (or more) of heat detection daily (early morning, midday and late evening);
  • That a heat detection aid or aids are used (such as tail paint and a vasectomised bull).

Uterine infection

The second factor associated with low three-week in-calf rate is low conception rate caused by uterine infection. Research at Teagasc Moorepark on identifying uterine infection is done using a metricheck device.

Five grades of score are identified:
  • Score 1: Clear mucus without pus – this indicates a healthy uterus;
  • Score 2: Mucus with flecks of pus;
  • Score 3: Mucus with <50% pus;
  • Score 4: Mucus with ≥50% pus;
  • Score 5: Mucus with ≥50% pus and odour.

Research at Teagasc Moorepark has also shown that cows with a score of two or greater should be treated with an intrauterine antibiotic subject to veterinary advice to cure the infection and increase conception rates.