June: A checkpoint in the season
Where cows are 30 days or more since service, early scanning can provide valuable clarity and allow time to act if problems are identified, writes Laura O'Connell.
For most spring-calving dairy herds, June represents a natural checkpoint in the season. Cows are now post-peak milk production and typically four or more weeks into the breeding period.
The intensity of calving and early lactation has passed, and attention is turning to how well cows are holding to service.
At this stage, the target submission rate should largely be achieved, and the focus shifts to conception to first service, repeat breeders, and cows that are not showing strong heats.
Many farmers describe cows as “quiet” at this point. While this can indicate successful breeding, it can also mask underlying issues.
Where cows are 30 days or more since service, early scanning can provide valuable clarity and allow time to act if problems are identified.
By week four or five of breeding, patterns begin to appear.
Repeat breeding, silent heats, and early embryonic loss are common challenges on dairy farms.
While heat detection, AI timing, and semen handling are often questioned first, nutrition is frequently a contributing factor, particularly during the transition from peak to mid-lactation.
Cows that are losing body condition, experiencing fluctuating intakes, or operating in negative energy balance are less likely to conceive and maintain pregnancy.
These risks increase during June, when grass growth accelerates and grazing management becomes more demanding.
June often brings ideal conditions for grass growth — heat, moisture, and fertiliser availability. Growth rates of 80kg DM/ha and higher are common. On many farms, grass supply can quickly outpace demand, particularly where silage ground has been removed from the grazing platform.
Surplus grass is not a problem in itself, but how it is managed has major implications for both milk production and fertility. Allowing covers to become too strong, or forcing cows to graze heavy residuals, reduces dry matter intake and lowers the energy density of the diet.
This is often reflected in falling milk yield and milk protein percentage. These are early indicators that cows are not meeting their energy requirements at a critical stage of breeding.
When intake drops, cows draw on their own body reserves to sustain production, increasing the risk of poor conception, embryonic loss, and extended calving intervals later in the season.
Milk protein percentage is often one of the earliest warning signs of nutritional stress. A decline beyond normal seasonal trends typically reflects reduced dry matter intake or inadequate energy supply relative to demand.
Monitoring milk solids trends alongside grazing conditions can therefore provide early insight into emerging fertility issues.
Where grass is getting ahead of demand, early intervention is critical. Removing surplus paddocks for bales helps maintain sward quality across the rotation and protects intake.
Cutting grass early, rather than waiting for it to bulk up, produces higher-quality silage and allows paddocks to return to the grazing rotation quickly.
Increasing stocking rate with other stock is another effective strategy where possible. The key objective is to avoid forcing cows to graze poor-quality residuals that compromise intake and performance.
Producing high-quality bales in June can also provide valuable feed later in the season when feed deficits or gaps arise.
The hard work has already been done in getting cows to peak milk, but maintaining performance after peak is where most gains and losses actually occur.
Managing the rate of decline becomes increasingly important. Looking back on milk reports for June and July in previous years can be very informative. Ideally, from peak, weekly declines should be less than 2.5%.
On many farms, the drop-off is greater, often driven by cows’ intakes not being met, grass quality issues, or insufficient supplementation during periods of high demand.
Buffering with high-quality silage or concentrate during these periods can help stabilise performance, support intake, and protect body condition, particularly in cows under breeding pressure.
Breeding performance is not determined by a single factor. It reflects the cumulative effect of nutrition, grassland management, cow condition, and attention to detail.
June offers an opportunity to assess how the season is unfolding and make timely adjustments that can pay dividends in fertility, milk solids, and overall herd performance.
- Laura O'Connell is an InTouch feeding specialist at Alltech Ireland.
