As I write this week the sun is shining but you know that the rain is not far away with heavy and sometimes persistent showers. It is now becoming clear that the high levels of rainfall are having differing effects on growth and utilisation on farms. Dry farms continue to record high growth rates ranging mid 50’s to mid 70’s kgDM/ha/day but the wetter farms are less ranging from low 40’s to 50’s kg/DM/ha/day. These growth differences affect the ability of the farm to build cover.
Many dry farms are now ahead of target in terms of building cover. Already on a 24-26 day rotation, these farms should try to keep to on this rotation length for another week as they expect continued high growth. When using the grass wedge this week – keep the target line set for a 25-26 day rotation and skip the heavy paddocks – try to cut these paddocks as soon as possible. If you build up too much cover in this period of high growth, you will fail to control supply and the continued heavy covers will affect graze out and subsequent re-growth through the Autumn.
In contrast, wet farms or farm realising poorer growth, should continue to plan to extend the rotation to 28 days by end of August and set the target line in the grass wedge accordingly. If you are behind target according to the Autumn budget then supplementation is required.
The consequence of building farm cover is that pre-grazing covers are also higher than so far this year. In these changeable weather conditions, ensuring good graze out (approximately 4.0cm) and high sward utilisation will be the challenge. It may be time to re-introduce the strip fence to allow for 12-24 hour allowances – down from 36-48 hours. If you move to a 12 hour allowance be prepared to check on the grazing conditions through the day and at dusk at night – confinement in a small space is not ideal in wet weather and with some heavy deluges, poaching can occur. Even though we are still in mid-August the option of on/off grazing must now be considered again especially on wet farms.
As mentioned above, most farms are now building cover with high pre-grazing covers. In the past week it is noticeable that farmers, and myself included, are underestimating these heavy paddock covers when eye-balling. With this in mind, be prepared to get down on your knees and cut a few paddocks with the clippers and quadrant to calibrate the eye. Off course the other variable in the calculation is the grass dry matter which is as changeable as the weather conditions. As a general guide, grass cut with a lot of surface moisture will have a DM% of 13-14% while grass with little surface moisture will have a dry matter of 15-16%. It is noted however, as rotation length increases; dry matter % will also increase as we enter the Autumn grazing period.
