In spring 2018, John Hally, who farms outside Cashel, Co Tipperary, reared 102 dairy-cross calves as part of the Thrive project. These were a mix of steers and heifers, made up of Aberdeen Angus, Hereford, Limousin and Belgian Blue calves from known AI sires.

From spring 2019 onwards, the Dairy Beef Index (DBI), developed by ICBF and Teagasc, has been used to select calves for the Thrive project. The objective of the programme is to identify beef sires that tick the boxes for dairy herds in terms of calving ease and gestation length, while delivering a calf of high genetic merit with positive carcase traits for the beef farmer.

The objective of the programme is to identify beef sires that tick the boxes for dairy herds in terms of calving ease and gestation length

On 10 February, the final nine of John’s 2018-born animals were slaughtered – all of which were Belgian Blue steers. The rest of the group were slaughtered from grass, with some meal feeding from early October through to early December.

With a full year’s data under our belt, we are able to look at some of the statistics from this batch of calves. However, we must remember that this is just over 100 calves from a total of nine different sires, so any individual sire results may not hold true on a national scale. In saying this, there are some interesting trends and results from the data.

Slaughter data

Table 1 ranks the bulls used according to their beef value figure within the DBI. It is important for beef farmers not to get too hung up on the overall DBI and instead look for what the beef value proportion of the index is bringing to the table.

Take the case of the bull BB2145, which has a negative overall DBI of -€42.

However, the beef value is €150 due to a high carcase weight value of +26kg but he is severely negative on calving traits (-€192) with a cow calving difficulty figure of 11.8%.

We must remember that these bulls were used in summer 2017 and, since then, a lot more data has been captured on.

With a calving figure as high as this, it is unlikely this bull will be used on dairy cows in the future. He now ranks 156 on the latest DBI active bull list released in January this year.

While bulls with the highest beef value DBI had the highest carcase weight and best grade, some of the group were rehoused for finishing on a high-concentrate diet.

Carcase gain per day is a good measure to look at as it takes the age variation at slaughter out of the equation. While the difference between all sires may seem small, (ranging from 0.42 to 0.47 for heifers and 0.47 to 0.51 for steers) with an average slaughter age of just over 20 months, each 0.01 increase in the carcase gain/day figure is worth over €23/animal in terms of carcase value.

Notably, the Hereford bulls KZP, GGM and HE2463 had some of the highest carcase gain/day figures.

However, their DBI beef value meant they took three of the bottom four places within the steer sires used. This is perhaps reflected in the fact that the bottom two bulls tended to have a higher carcase fat score at lighter weights.

Calf date of birth

For the purposes of this comparison, the final nine animals that were fed indoors for an additional nine weeks until early February have been excluded as once we introduce a second winter period it becomes a different system – a route John Hally is not looking to go down.

Table 2 looks at the average number of days on farm and average carcase weight across both steers and heifers. Calves born in February spent 588 days on the farm with a carcase weight of 308kg. March-born calves were on the farm for 564 days and had a carcase weight of 283kg. While the number of April-born calves was low, they spent on average 515 days on the farm and averaged a carcase weight of 275kg.

What is striking is that although February-born calves were on farm for 24 and 73 days more than March and April calves, this resulted in a heavier carcase weight of 25kg and 33kg, respectively. Valuing this at the average kill price (€3.78/kg) received for these calves translates to an additional €94.50 and €125/head for February-born calves compared to March- and April-born calves, respectively.

Interestingly, there was no great difference in slaughter date across the three groups, with only one day between February- and March-born calves, with April-born calves actually slaughtered earlier, albeit just over a week in the difference.

This reiterates the benefit of getting calves on farm as early as possible in spring.

This reiterates the benefit of getting calves on farm as early as possible in spring. In reality, large numbers of beef-sired calves won’t be born before March and into April. The difficulty with the late March- and April-born calf is that the window of opportunity to get these calves away at a significant carcase weight, prior to the second winter period, is quite tight. Come early November of the following year, these animals will be just hitting 19 months old.

While there is still a place for these later-born calves, farmers should be aware that these animals will more than likely require a more expensive indoor finishing period and this should be reflected in the price paid for these animals as calves.