The maternal herd, based in Teagasc Grange, was established in 2012 with a focus on validating the beef replacement index. Heifers were selected to operate two breeding strategies: cows sourced from the suckler herd (three-quarter bred) and first-cross beef cows sourced from the dairy herd.

These animals were selected on their genetic merit with a focus on establishing two diverse genotypes of high genetic merit animals and low genetic merit animals.

The first cows in the herd calved in spring 2014 with two years’ production data now cumulated. Analysis of data from the 2014 production year was clouded in confusion, as when data was presented on the sire level, there was a very narrow range in the genetic merit of animals, with animals described as being very high genetic merit and high genetic merit.

A decision was taken in 2015 to analyse data at cow level which delivered a sufficient range to allow animals to be separated into high and low genetic merit groups.

Cows in the high genetic merit group have a replacement index value of €119, while the low genetic merit animals have a replacement index value of €50.

On a star rating, this compares with a five-star animal and a two-star animal with the difference essentially meaning high genetic merit animals should be €69 more profitable each year than their counterparts in the low group.

Predicted differences

The difference in predicted value comprises a multitude of factors, including aspects such as production performance, cow survival, feed intake, carcase traits, etc.

Table 1 details a number of predicted transmitting ability or PTA cow differences for a range of important production parameters. The herd is run commercially with a range of measurements collected, including the onset of puberty, calving performance, liveweight and body condition score, reproductive performance, milk yield and calf performance.

2015 performance

  • Calving: Calving performance of the herd is detailed in table 2. There was no significant difference between the mean calving date, age at first calving, BCS and liveweight two days post-partum or in calf traits. On a herd basis, there were 21 calves lost out of 126 born to 123 cows. The effect of mortality was limited somewhat due to strong reproductive performance with 0.85 calves produced per cow. Herd researcher Robert Prendiville said nine calves were born dead, including six stillbirths with two half-twins lost, two underdeveloped/deformed calves and one case of abortion from a Neospora positive cow. Thereafter, he reports two casualties, three calves put down, an unexplained loss at four days of age, a case of internal bleeding due to a ruptured navel, three cases of pneumonia, one death due to Cryptosporidium and one unknown cause.
  • Reproductive performance: As mentioned above, breeding and reproductive performance gave the herd a strong platform to work off. This is detailed in table 3 with no statistical differences found. Explaining breeding practices, Rob says breeding started in late April and ran for 13 weeks with three rounds of AI and stock bulls used for the final four weeks. This differed slightly to 2013/14 when AI was used for six weeks and stock bulls for seven weeks. Terminal Aberdeen Angus and Limousin sires were used in AI and stock bulls. Cows were monitored regularly with tail paint and vasectomised teaser bulls utilised as aids for heat detection.
  • Calf performance: Table 4 details calf performance. Milk yield data was collated by weigh-suckle-weigh procedure and showed high genetic merit cows delivered an average of 1kg more milk. The weaning weight on 3 October was not statistically different with high genetic merit sired calves 7kg heavier. Rob explains the assessment on calf value and proportion suitable for live export was calculated by a mart manager, an auctioneer and a live export operator valuing the progeny.

    • In terms of production efficiency, Rob explains they are seeing a tendency of high genetic merit cows producing slightly more milk per unit of energy intake. High genetic merit cows have a milk yield per kilo of grass dry matter intake of 0.58 versus 0.51.

    Table 5 details a number of PTA differences between high and low cows and the actual difference that was recorded. Differences realised to date in the herd are small and as demonstrated in table 6, which details the economic value of a unit change in the different traits, the predicted difference of €69 on the replacement Index has not been realised after the first two years’ production. The carcase weight value of €21.78 is a predicted value based on weaning weight as cattle are only starting to be slaughtered. Slaughter performance, once available, will be added back into the analysis, as will data such as cow survival and feed intake. The trial is a long-term one, which will run over five lactations with any changes in fertility and calving interval along with survivability accounted for on an ongoing basis in the economic analysis.

    To read the full Suckler Focus Supplement click here.