The last ended with the suggestion that we could do with some rain. Now that it has come to pass what has the outcome been?
For most the rain was welcomed and has stimulated a significant increase in growth rate ranging from 40 kgDM/ha to 70kgDM/ha. Those on the lower end of the scale are generally the colder later farms who are yet to raise farm cover above 450 kgDM/ha, while the latter are farms who already had a strong farm cover and the increase in growth has sent them into surplus. Whichever category you lie in, you will need to make decisions to control the surpluses.
Applying the correct demand is the critical issue for the next 8-10 weeks and understanding what demand your farm can cope with is the important point. So, a reminder of what “demand” actually means. Demand is the amount of grass dry matter which is eaten off the farm every day and is expressed in kgDM/ha/day. It is calculated by the number of animals on the platform, multiplied by their daily grass DM intake, divided by the area (ha) of the grazing platform. With further high growth rate suggested through May & June, demand must be increased accordingly by either increasing the number of animals on the platform or reducing the area of the platform. The latter is usually the case, by closing area for first cut silage.
In general demand should be increased to 60-70 kgDM/ha/day until aftergrass from first cut returns to the platform. Your position within this range depends on the farms ability to grow the on average the same amount through this period. Farms with poor grass species and soil fertility should err on the lower end of the scale while and visa versa for ryegrass dominant farms with good fertility. Wetter farms with good species etc may also align themselves at the higher end of the scale due to their ability to grow well in warm drought like conditions. For farms which will drive a demand of 70 kgDm/ha/day or more, it would be beneficial to close paddocks for silage which have a range of covers currently - this allows for a split of the first cut, allowing an earlier reduction of demand with earlier aftergrass.
Speaking to many farmers, there is a concerted effort to “fill the pits” again. Some will feed concentrates through May/June to reduce demand and allow extra ground to be closed for first cut. Remember grass crude protein levels remain high due to the high leaf to stem ratio in the sward – there is no need to feed expensive high CP concentrates.
On a similar vein, the high leaf to stem ratio seems to be playing havoc with milk butterfat levels – in some cases down to 3.20% for a Jersey x Friesian herd! There only explanation that can be given for this drop in fat % is the exceptionally low levels of fibre in the diet, again related the high leaf to stem ratio, a result of excellent graze out of sward through the Spring. Examination of swards at the end of last week showed that some tillers have gone reproductive, with miniature seed heads moving up from below. As they rise, what follows behind is true stem of low digestibility. At this stage they are still below the grazing horizon – paddocks grazed these days will not remove these seed heads – therefore they will be in the grazing horizon the next time they are grazed. From now on it is critical that the grazing pressure is not relaxed – these developing seed heads must be removed as low as possible – otherwise stem will make up a significant portion of the grazing horizon at the next grazing – good for fat% but disaster for protein%.
