Growth rate in the past week were, as predicted, down on the week before ranging from 35 kgDM/ha/day to 65 kgDM/ha/day. This drop is in line with the continued heavy rainfall and drop in air temperatures. 9am soil temperatures are now, in almost all case below 15 degrees and down to 13.5 degrees on colder wetter farms. This also had the effect of lowering growth rates in the past week.
However, for the first time in a long time we have a positive weather outlook for the coming week. With the exception of Monday and a little of Tuesday high pressure looks to command our weather pattern through the week bringing higher air and soil temperatures and increased sunlight – therefore expect and budget for an increase in growth rate. This increase is very much welcomed in attempting to put farms back on target for their Autumn budget. Don’t forget to adjust accordingly when estimating the dry matter % of grass when measuring – little or no surface moisture on the grass will yield a dry matter percentage of 16-17%, and the longer it is growing the higher it will be.
Given that many farms are well behind in their fertiliser application over the past 2 weeks, it may be prudent to blanket spread the farm mid-week as the final application before the deadline instead of waiting another week. If grass growth is to be maximised in this short period of improved weather then it is essential that there are adequate nitrogen levels available in the soil.
Graze out in paddocks has been poor over the last 3 weeks due to the weather conditions. Once the strip wire is introduced with maximum 24 hour allocations and on/off grazing applied – then little more can be done to improve graze out. The coming week is the time to act on those under grazed paddocks from the previous rotation – if you are on target with regard to the Autumn budget, then you can afford to skip some heavy paddocks and graze out the paddocks which were poorly grazed in the last rotation – try to graze them with a cover of <1200 kgDM/ha. If you don’t address them now, you may not get a chance later in the Autumn.
On a similar vein, I have just returned from a farm which was on target with regard to Autumn budgeting but was finding it very difficult to graze out paddocks. Pre-grazing covers ranged from 1800 to 2200 kgDM/ha and 12-24 hour allocations were applied. Residuals covers after grazing of 200-300kgDM/ha was the result, meaning that the final grazing in each paddock was lost and a required extension of the rotation (now 28 days) was not being achieved. With 3 paddocks remaining at high covers, the recommendation is to pre-cut these paddocks, maximising utilisation slowing down the rotation and ensuring excellent sward quality for the next grazing in October.
Ideally, rotation length in early September should be approximately 32 days extending to 35 days in mid-September. Remember that rotation lengths should be a product of growth rate at the time. If growth rate is high then rotation length should be shorter than target and visa versa.
Another little tip. Unfortunately, some farmers are forced to introduce concentrate and/or silage into the diet in order to lower demand and build farm cover. While in most cases concentrate can be fed in the parlour, the logistics of feeding silage before or after milking is more difficult especially if feeding space is limited. An option is to feed a proportion of the cows on silage for each grazing with the remaining proportion grazing. Rotate the cows on silage and grass so that it does not impinge on their production – for ease of management the best way to do this is to do so on the basis of the rows of cows in the parlour.
