Grass growth rates have surely taken off this week with growth rates averaging about 77kg of dry matter (DM)/ha/ day and is set to continue for the next week at least.
As things are getting busy on farms with the start of the breeding season and cows getting served along with preparation and harvesting silage, grass can easily get out of hand, which could impact cow performance.
A lot of farms turned a corner in terms of average farm cover (AFC) very quickly in the space of a few days, as many farms went from a deficit to a surplus as soon as the sun arrived after heavy rain.
This good weather is presenting farmers with an opportunity to get silage cut and into a pit or baled at an optimum quality of over 72% dry matter digestibility (DMD).
While it is hugely important to make quality silage, it has to be done while maintaining quality of grass in front of the cows, as with growth rates flying it at the moment, it is very easy to be left with stemmy, poor quality covers very quickly.
Keeping ahead of grass
Every farm is different and every cow is different, meaning some farms and cows are able to handle slight surpluses in grass very well depending on dry matter intakes of the herd and the soil type on the farm.
However, most farms in the country have a surplus of grass with current covers at over 200kg DM/livestock unit (LU). Too much excess grass must be handled.
Grazing covers of over 1,500kg DM/ha only leads to poor animal performance in the milking parlour, poor clean outs, and slows down re-growths and recovery.
Some farmers squeal at the thought of taking out paddocks with surplus paddocks for bales, but it means that cows can get ahead of the grass and stay grazing lush, highly digestible, quality grass that maintains peak milk production.
However, in order for this to work and to avoid any deficits in subsequent rotations, these paddocks should not be left to ‘bulk up’ but should taken out immediately and fertilised, ready for the next rotation.
When growth rates take off, farmers should start walking the farm every five days, which is understandably difficult at a busy time of the year but is definitely worth it to make rapid decisions.
Your pre-grazing yield target should be around 1,400kg of DM/ha when the grass plant is at the three leaf stage and highly palatable.
When grass covers go over this target, it is a strong indicator of surplus grass and farmers should be aiming for 4-4.5cm of a post grazing height to encourage re-growths whilst not impacting cow performance.
The problem is that when cows go in on high pre grazing cover of about 1,500-1,800kg of DM/ha, they are going to leave poor residuals of about 5cm, which will affect that paddocks ability to recover for the next rotation.
Also, grazing stemmy covers will only lead to a hit on your milk protein percentage, so going in on optimal covers and grazing paddocks every 18-21 days is advisable as the grass goes through cycles where it grows new leaves every three weeks.
Lower proteins occur when the stem gets longer as the protein gets suppressed due to the reduced intakes and energy density takes a hit as well.
The demand for grass on the farm should be increased when a surplus occurs and can be done through reducing the amount of meal being fed.
It may also give farmers the opportunity to cut for bales and reseed the paddocks which will increase the demand on the farm, and when the weather is ideal for reseeding, maybe it’s an opportunity to do so when grass is not an issue.
Removing paddocks for bales is still the obvious one and bringing back replacement stock or dry stock to the main platform is another option.
