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Grange Maternal Herd update: 88% submitted for AI in the first 21 days of breeding

Grange Maternal Herd update: 88% submitted for AI in the first 21 days of breeding

The Teagasc Grange Maternal Herd consists of 90 cows made up of Limousin x Simmental or Simmental x Limousin cows. The herd calves from the first week of February to the end of April.

Usually heifers and cows that have calved are turned out as soon as weather conditions allow to settle them. This spring was very challenging; three weeks after the first groups were turned out we got heavy rainfall, some had to be rehoused and we thought this would affect the breeding season, thankfully May has been a great month.

Breeding 2023 commenced on the 2nd of May and will run until the 11th of July. We carried out a pre-breeding scan the week before and it did pick up some issues; 4 ‘dirty’ cows and 30% of the heifers were not cycling. Sexed semen will be used to produce heifers for upcoming experiments. With AI, heat detection is crucial, we use tail paint on cows, a vasectomized bull wearing a chin ball, and digital methods in addition to visual observation. 88% of breeding animals have been submitted for AI in the first 21 days of breeding.

Herd profile

The Maternal Herd operates on a land area of 42ha. The herd comprises of 90 spring-calving suckler cows. The spring-calving herd is a grass-based system, whereby the objective is to maximise the proportion of lifetime performance from grazed pasture.

The Maternal Herd at Grange was originally established in 2012 to validate the Euro-star Replacement Index. The Replacement Index value of a sire/dam is a monetary value which indicates the additional profit per replacement female bred from that sire/dam, due to improvements in fertility traits, milk yield and beef merit, when compared to a sire/dam with a value of zero. For example, a breeding bull with a Replacement Index of €160 is expected to produce daughters that will generate on average, €160 more profit when compared to daughters of a breeding bull with a Replacement Index value of €0. The current study will be completed in 2023 and focus will move to developing strategies to reduce age at first calving and age at slaughter in a late-maturing suckler cow herd.

Breeding 2023

The breeding season started on the 2nd of May and will run for 10 weeks until the 11th of July, in this time 114 animals will bred. The herd uses 100% artificial insemination. In 2023, the herd will use two rounds of sexed semen on all animals to generate heifers for upcoming experiments; the bulls selected are outlined below.

A pre-breeding scan was carried out on the 28th of April, this scan detected four cows that required a uterine ‘wash out’ and that 30% of heifers had not yet cycled. The non-cyclic heifers had all met the target minimum weight of 380 kg and normal follicular activity was reported so it is unknown why these heifers had not yet cycled. This scan is very useful as the cows that required a ‘wash out’ would likely have not cycled or the infection could have progressed into endometritis.

Heat checking is very important for good conception rates when using AI. Heat detection is facilitated by the following aids:

  • Visual observation
  • Vasectomized teaser bull wearing a chin ball
  • All animals have tailpaint applied
  • Digital technology

The availability of sexed female beef semen has increased in Ireland in 2023. This technology allows farmers to increase the chances of getting a heifer and potential replacement from their heifers or best performing cows. Two rounds of sexed female semen is being used on all animals followed by one round of conventional semen to generate heifers for upcoming experiments.

For conventional semen, the AM/PM rule is normally applied for AI. Animals observed in standing heat in the morning are submitted for AI that evening and animals observed in standing heat in the evening are submitted for AI the following morning.

For sexed semen,you are still using the AM/PM rule but  the recommend AI time is 16 – 22 hours after first observed in standing heat with the later the better in this timeframe applied. For sexed semen at Grange, we are inseminating animals 22-24 hours after the start of standing heat.

  • Animals will get two opportunities for sexed semen as follows:
    • 1st AI – sexed female
    • 2nd AI – sexed female
    • 3rd AI – conventional

Bull selection

While the choice of bulls available as sexed female has increased in 2023, farmers are still not spoiled for choice. When selecting bulls, we aim to select bulls that are

  • At least 4/5 star on the Eurostar replacement index,
  • Have a maximum of 8% beef heifer calving difficulty
  • Are balanced for calving interval, daughter milk and carcass weight

In 2023, the maternal herd requires a mix of early and late maturing sires and we have chosen Aberdeen Angus, Hereford, Limousin and Simmental breeds. The requirement also means that, where possible, bulls would be used across both heifers and bulls. The bulls used are AA4303, AA4743, HE6936, LM2014, LM7416, SI4147 and SI7491.

Breeding to date: 23/5/2023 - 21 days of breeding

  • 88% of animals (100) have been submitted for breeding in the first 21 days of breeding
  • There have been 11 repeats
  • All cows that received a ‘wash out’ have been submitted for AI
  • A 30-day scan will be carried out at the beginning of June on:
    • Animals not submitted for AI
    • Animals AI'd greater than 21 days

Observation for repeats will now become paramount. We don’t use a stock bull, but if you do, visual observation is key, firstly to see if he is serving the cows, make sure to note the dates of serves in a notebook. In three weeks, these dates will be vital to spotting any issues, if you see repeating cows act immediately.

Colin Byrne, Teagasc Grange provided this update as part of the Future beef Programme newsletter for June.