Scottish dairy farmer scoops top spots in August DWP heifer proof run

Bruce Mackie of the Rora Holstein herd, Middleton Farm, Aberdeenshire, has four animals ranked in the top 10, including heifers in the top two positions.

DWP is a complete selection Index in the genomic test Clarifide Plus. It includes 14 health and wellness traits alongside the standard traits usually provided. DWP is based not only on lifetime productivity but also places considerable emphasis on health, thereby giving an overall view as to how profitable each animal is likely to be.

The highest-ranking heifer in the August proof run, Rora Norton Hopeful, is June 2021-born with a DWP of 1243. She is sired by Mr Wings Norton, who was selected because he scored highly on health traits and with a lifespan of 150 days.

The second highest ranking heifer, Rora Captain Raducanu, is September 2019-born with a DWP of 1209. She is sired by Genosource Captain, who has a £PLI of 1014 and ranks highly on health with a Lifespan (days) of 131 days.

Mr Mackie, who only fully started genomic testing his heifers in 2019, has achieved top results by selecting his heifers and most of his bulls on their DWP figure.

He said: “I have been selecting genomic bulls on DWP, but not every company publishes a DWP figure. When that’s the case, I choose bulls I predict would have a high DWP figure by looking at their health traits and lifespan with decent milk. DWP is the index for us. It’s always in the back of my mind when selecting bulls, even if they don’t have figures available.

“I use a range of bulls from different suppliers. It’s important not to have all my eggs in one basket with them not being proven sires,” he added.

Mr Mackie has bred sixteen 100-tonne animals in the last seven years. “Longevity is where we want to be. If we have cows that last, that must also lower the amount of carbon produced per litre of milk, so it’s a sustainable way of farming,” he said.

The organic herd currently averages 9,500-10,000 litres (4.15% butterfat, 3.31% protein) with the aim for all cows to produce over 50,000 litres in a lifetime. The average number of lactations per cow stands at 3.26, 19% above the average from Cattle Information Service (CIS) data of 2.74.

When Mr Mackie selects his replacements, he chooses the top 90 animals ranked on DWP. The current lowest DWP animal he will breed from has a figure of 553, which is considerably higher than the average DWP figure for UK tested heifers which is around 430.

All the top 90 DWP animals are bred to sexed semen, with the rest put in calf to Aberdeen Angus. He is currently running a replacement rate of 21-22% in his herd of 230 milking cows (400 including followers).

Although Mr Mackie only retains about 60 of the heifers as replacements, he has a good market for the remaining 30, with the animals not making his cut generally still above the national average for £PLI and DWP. These are sold mainly as in calf or calved heifers.

Colin Penny, Zoetis veterinary livestock consultant, said Mr Mackie’s success breeding top DWP heifers shows what can be done by careful breeding.

“Bruce has not used artificial breeding techniques, such as embryo transfer. Instead, he trusted the data, applied selection pressure to his heifers, and carefully selected bulls, mostly using DWP figures.

“It’s impressive how he has quietly worked away, and in a short time, his excellent breeding decisions have resulted in these top heifers. It’s testament to the time he has taken to carefully select his heifers and bulls for breeding,” he said.

Farmers with the highest-ranking heifer in the top 100 Dairy Wellness Profit (DWP) list are, for the first time, eligible for a prize of 15 free tests; and the highest-ranking heifer for a specific health trait, chosen by Zoetis, will receive 10 free tests.