Now is the time to decide on drying off
With the recent spell of dry weather and improvement in ground conditions, many dairy farmers have been frantic in their attempts to catch up on a number of tasks. Silage cutting, fertiliser and slurry spreading are all at the top of the priority list in an effort to get the farm ready for winter.
On a spring-calving dairy farm, the autumn is a time when a plan must be put in place in terms of grazing management, drying off and culling decisions to determine the number of cows that will be wintered and milked next year.
The whole plan should revolve around setting the farm up for next year. However, as a result of the lower milk receipts for 2012 and the reduced risk of superlevy, there is a big temptation this year to milk on.
Questions and debate about whether it will pay to feed 3-5kg of dairy ration to milk through December when it will cost well over €300/t are now being considered.
If we focus purely on the opportunity to milk on without a suitable management plan for the herd regarding drying off and forage supplies, there is a big risk that some of this extra milk will be produced at the expense of the cow, especially if it results in a cow milking it off her back.
For example, if a cow is milked throughout December producing 10l per day (310l in a 31-day period), she could easily lose body condition and end up calving at 2.6 instead of 3.
According to research by McNamara, the cow will produce around 4l less per day over the first eight weeks of the following lactation. This is a total loss of 224l over 56 days in the following lactation. So in these circumstances, the gain in milk for 31 days is only 86 litres and highly unlikely to cover the extra concentrate fed.
This is before considering the detrimental impact that low condition scores may have during the following breeding season.
You must prioritise the following in relation to next spring:
• Sufficient good quality pasture;
• Pastures in good condition for rapid growth in spring;
• Cows with a good condition score at calving.
This means that your management this autumn must not compromise your required closing grass cover of between 450-700kg DM/ha depending on feed budget.
Avoid taking covers over 1,500kg DM/ha through the winter, and cows must calve at a condition score of 3.25.
If we consider grass management, the autumn is a period characterised by the fall in pasture growth below pasture demand.
Therefore, the priority for grazing management is to extend the rotation and by mid-September most farmers should ideally be using around 1/35th of the farm, which corresponds to a 35-day rotation.
Ideally this will extend to a 40-day rotation by October 1, in tandem with an increase in pasture cover to +1,000kg DM/ha. A feed budget will help you plan this period and determine the amount of supplementary feed required.
Considering the quantity and, in particular, the poorer quality of winter feed supplies, strategically drying-off cows will be a priority this autumn.
Decisions need to be made now to avoid early calving in February or young cows being compromised in body condition by milking them on too long.
Where silage quality is lower than desired, the length of the dry period becomes more important. Also, drying-off or culling low-producing or high-SCC cows will prioritise the available feed for those that can make a return.
Where feed supplies are short, removing cull cows which are empty earlier than in previous seasons will provide a welcome relief on the winter-feeding supplies and may reduce the silage requirement of the remaining milking cows.
In this instance, scanning, milking recording, estimating feed supplies and feed budgeting are essential tools this autumn.
For a February calving herd, scanning cows in September is ideal, since it can be used to determine your drying-off schedule.
The table will aid you with these decisions and, if a cow or heifer qualifies for two or more of the descriptions, then be ready to dry her off.
These same principles can then be revisited for animals still milking in November and December.
Dr Mary Kinston is a farm consultant based in Kerry. Mary.firstname.lastname@example.org
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