Usually an advocate of the `if it ain’t broke, don’t fix it’ approach to farming, Mark was happy with his Holstein herd’s cell count and health profile.
“Our cell count has always been pretty good and I initially thought why change something if it isn’t a problem.”
Three factors swayed his thinking: the lack of dry cow treatment to enable blanket therapy to continue, the potential to save money by reducing its use, and changes to microbial stewardship regulations.
DataGene’s selective dry cow tool has delivered on all counts and Mark expects it will be an ongoing part of Craiglands Holsteins that he runs with wife Sam Simpson.
Blanket dry cow therapy refers to the practice of treating all cows in the herd with intramammary antibiotic at drying off. Selective dry cow therapy involves treating only those cows with evidence of infection.
Prior to this year, Mark and Sam applied blanket dry cow therapy across their herd, but there were good reasons for change.
“The first issue was the availability of dry cow [antibiotic],” Mark said.
“It has been in short supply and that’s likely to be the same again next year for a whole range of different reasons.
“The next incentive was to save money and the other thing was that new microbial stewardship requirements came in from September 1.
“There are new European Union requirements for our dairy exports, making sure we’re recording what drugs are going into what cows at what stage and what for. For those reasons, we turned to the DataGene selective dry cow tool.”
The tool determined only 20 per cent of their cows needed dry cow treatment this year, resulting in a substantial saving in antibiotic use.
“There has been a substantial financial saving and we haven’t seen any negative health impact on the herd,” Mark said.
The tool has been designed to ensure herd health.
“Within the tool, you can select the average cell count level you want for mature cows and first lactation cows,” Mark said.
“I set pretty tight margins but if we were drying off 50 cows in a group, there might have only been 10 at the most that we put dry cow in. So, we’re saving 80 per cent.”
Any cow that went over 250,000 average cell count in any test across the year and any heifer that went over 100,000 received selective dry cow therapy. All cows and heifers still received blanket teat sealant to protect against new infections during the dry period.
Mark says this year’s results have convinced him to continue the selective dry cow tool.
The herd usually calves May-June but that has been spread out this year due to the impacts of the 2024-25 drought.
“We had wet periods when we were calving but our cell count is actually better than it was last year,” he said.
“There could be other reasons for that, but the point is that by using selective dry cow it hasn’t adversely affected our cell count,” Mark said.
“There were only a couple of cows with mastitis. That’s about the same as other years, but we’ve saved a lot of money and haven’t put antibiotics in cows that didn’t need it.
“That helps with microbial stewardship. Under the new regulations, you’ve got to have a valid reason for putting antibiotics into cows.”
Mark says it is a simple tool to use. To use it, the herd must have been herd tested at least once in the 80 days prior to dry off.
“Once I set it [the cell count thresholds], every time I dried off a group of cows, I just ran the report straight out of the DataVat website and highlighted the cows that needed to be treated.
“We tracked all of them through the dry period, making sure we didn’t have any flare-ups and there wasn’t a problem.”
The selective dry cow tool is just one more way Mark and Sam can use herd data to make decisions during tough times.
They have been genotyping cows and calves since 2015 and that backlog of information was invaluable during the recent drought when they reduced the herd from 400 to 300 cows.
“We had good data on cows as far as their genetic ability goes so we used the Balanced Performance Index and herd tests to rank cows and decide which ones to let go,” Mark said.
“Because it has been a closed herd, we’ve got extensive pedigrees on all our cows. We worked really hard in building up the genetic merit of the herd and we’ve concentrated on staying a closed herd.
“Every year the BPI level of the herd is improving and it’s already quite high. We’ve got clean-up bulls out of our cows now over 400 BPI.”
Mark and Sam are now rebuilding numbers using replacements, and again the genomic data is at the heart of their decision making.
“We’re using genotyping to identify the cows we don’t want to breed replacements from and instead breeding them to higher-end Angus semen,” Mark said.
“We’re back up to 350 but I’d like another 50 cows on the farm. We’ll be back to that number in a couple of years because we know we’ve got good replacements coming through.”
“With our AI program, we’re working to get calving back to May-June. The challenge last year was in May-June we had no feed. We didn’t start grazing until September,” Mark said.
“Over the next two years, the replacement heifers will be inseminated to calve May-June and we’re doing synchronised programs to bring the others back in the system.
“We don’t usually do a lot of synchronising. We want to get away from using a lot of drugs. That’s an overall goal with the benefits of cost savings and trying to get cows on natural heats.”
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