August is essential for springtime planning
Published 19/08/2015 | 02:30
The weather is probably the most talked about issue in Ireland. While most families have been disgusted with this year's summer as the school holiday draws to an end, for dairy farmers it's been hard to complain.
Grass has grown reasonably well and conditions have neither been too wet nor too dry. However silage cutting has been rather chancy. Even where farmers have checked every forecast available, knowing when to go for it has been challenging. As a result, some second cuts have been either cut slightly wet or have been caught with a splash whilst wilting.
At times it has also been rather chilly and as a result soil temperatures have been fluctuating up and down having fallen from highs of 20C to lows of 15 to 16C.
Whilst grass has continued to grow, this has had some impact on growth rates. Personally I find a noticeable difference in both the rate and look of the regrowth once the soil temperature falls below 17C. This matches what a scientist once told me - that there was a substantial amount of organic nitrogen available once the soil temperature was above 17C.
Below this temperature there was a greater reliance on nitrogen fertiliser to provide the grass plant's needs, and I tend to believe this having noticed lighter green and slower regrowths at lower soil temperatures.
So if it's colder than normal, it's not a time to contemplate skimping on nitrogen fertiliser. However if the temperature rises substantially, it might lead to a flush in growth but also a rejection of pasture if they become too nitrogen rich. Once again, measuring soil temperature can be a great aid to management decisions.
August is a critical month on the grassland management calendar as it's the time when planning and preparation for spring should begin.
Essentially you should now resist trying to cling on to an ever falling milk production and avoid making decisions focusing solely on the tank. In essence, there are three core aims of autumn management:
• provide sufficient quantity of good-quality pasture for cows in spring;
• promote pastures which are in good condition for rapid growth in spring;
• have cows which are in adequate body-condition score at calving.
Whilst these seem distant targets, getting these essential elements right requires timely decisions during the autumn. Do not underestimate the importance of body condition score! The sustainability of seasonal calving is reliant on a condition score of 3.25 at calving for 90pc of the herd, and is essentially determined by your drying-off decisions.
The removal of quota restrictions and the increasing desperation of farmers to prop up income, may see the improvements of the last two years in calving rates and breeding eroded in one season if this isn't given due consideration.
An adequate condition score requires good feeding and, most importantly, time. August is also a time of year when dairy farmers should start to lengthen the grazing rotation.
The aim of this is to push grass forward into the autumn in an attempt to extend the grazing season. However, August is a tricky month to manage.
Whilst one may be happy that there is an increase in the pasture cover, August can often see surpluses quietly manifest to a level that requires action.
If you see your grass cover increasing substantially and rotation lengths already exceeding 30 days then it is better to cut paddocks for silage in mid to late August.
Otherwise there'll be far too much grass in September, which may require a late cut or the cows eating through exceptionally heavy covers affecting grass growth and milk production.
Therefore it's crucial to do a weekly pasture walk to manage the grass supply and demand at this time. Of course it depends on the farm and the stocking rate but I find that holding a grazing rotation of 22-26 days up until around August 20 works well.
From that point onwards it is ideal to start increasing the rotation length to hit roughly 30 days by September 1, 35 days by September 15, and 40 days by October 1.
More often than not, growth does occur in September, which should mean this will coincide with an increase in the pasture cover up to or exceeding 1,000kgDM/ha by October 1. Avoid increasing this above 1,200kgDM/ha by that date if you want to maximise October and November grass growth rates, tillering, grass quality and grazing residuals.
Personally I feel that extending the rotation to targets specified is more important than the actual cover accumulated. The last grazing rotation should then commence in and around the first week of October.
Mary Kinston is a discussion group facilitator and consultant, and farms with her husband in Kerry. She can be contacted at firstname.lastname@example.org