Following the warm June bank holiday weekend, temperatures have dropped significantly, which has seen grass growth rates fall back on dairy farms around the country.
Met Éireann has predicted a cooler airflow to continue over the next seven days, which could see a stagnation in grass growth rates.
According to Pasturebase Ireland (PBI), grass growth has dropped in the last number of days, as the average dairy farm was growing 65kg of dry matter (DM)/ha last week with a demand of 57kg DM/ha.
PBI also identified that 40% of farms are now under 170kg DM/livestock unit (LU), which is not a crisis but something to be weary about.
Reacting to poor grass growth
In the scenario where pre-grazing yields start to drop below 1200kg DM/ha or if you are below 150kg Dm/ha, a few methods may be considered:
- Aim to hold your rotation at 21 days;
- Increase the grazing area, if possible;
- Feed extra meal in the parlour;
- Supplement with silage.
Some of these methods might not be possible for many farmers but at least one method should be a priority to rectify any grass shortage.
You will only be able to identify a grass shortage and keep a close eye on Average farm cover (AFC) , cover/LU and rotation length by walking the farm every five days during this cold period.
By walking the farm every five days, it will allow for quick rectification and mitigate the chances of your cow production levels falling.
The aim throughout this cold weather should be to try and maintain a cover/LU of 170-200kg DM/LU, as this will match demand in the coming days.
The advice from Teagasc is, that even though there may be a number of paddocks with poor grass quality, correcting all paddocks in a rotation should be avoided.
Even though this might correct grass quality in the next rotation, it might put your farm into an unnecessary grass deficit as it will drop grass growth rates by 20-30kg DM/ha.
Returning paddocks that were taken out for bales
It is important to get paddocks that were taken out for bales straight back into the next rotation to maintain a 21-day rotation at this time of the year.
When cows graze a paddock, they recycle a lot of the nutrients through their dung and urine, which means that only 40% of phosphorus (P) and 10% of potassium (K) is removed from the paddocks.
However, when a paddock is cut for silage, it will see the removal of 100% P and 100% K, meaning your nutrient application post-cutting will have to be more vigorous.
To prevent a poor return of grass in paddocks that have been cut for bales, there should be 2,000gal/ac of dilute slurry applied or one bag/ac of 0-7-30 for every three to four bales/ac that was produced to replace the offtakes.
During this colder spell, it is important to keep on top of your grassland management in order to intervene on time, to ultimately, keep your cows producing high levels of milk and to maintain energy intakes during the breeding season.