Johnstown Castle Winter Milk Herd – Dry Cow Management
Ensuring autumn calving cows are in the correct condition for calving down will significantly reduce the risks of metabolic disorders and the increased workload and loss of production that goes with it. Dairy Specialist James Dunne outlines the dry cow practices in the Johnstown Castle research herd
The autumn calvers in Johnstown Castle are generally given 55-60 days dry. Extra days dry are generally not required because:
- thin cows at drying off are rare
- any dry cows <2.75 BCS at dry off can be offered extra grass intake for 3-4 weeks to correct low BCS.
First 6 weeks after drying off
For the first 6 weeks after drying off approximately, cows are grazed in rotation after the milking group, which will have grazed paddocks to around 5.0 - 5.5cm residual. The dry group grazes the paddock tightly to 3.5cm residual and moves on within 1 to 2 days.A longer duration would result in re-growths being eaten which slows grass growth and increases body condition score (BCS) gain of the dry group. This leader/follower grazing has the effect of limiting feed intake in the early dry period to ensure that excess BCS gain does not occur. Gut fill is not an issue during this period so supplementary hay/straw is not used. Any thinner cows can be grazed on full grass allocation for a few weeks to correct BCS.
At 16-20 days before expected calving date, cows are drafted to a calving paddock which has a standing hay crop established. This sward will have been closed 50 days previous and received no K fertilizer since spring. A pre-grazing cover of around 3,000kg DM per ha is expected. Approximately 1 ha per 30 cows is required for the total dry period. Cows are strip–grazed through this crop, offered 5-6kg DM once per day along a long axis. The balance of forage intake is also provided as moderate DMD, low potassium, <1.8% DM haylage in ring feeders. Cows consume approximately 5 to 6kg DM of this material, so 1.5 to 2 bales per cow will be adequate for the dry period.
It is important to conduct a mineral analysis of bales; some haylage can be higher than expected in K content and should not be fed to close-up dry cows. Re-growth pasture is 100% leaf and can have high energy and K content; therefore it is not suitable for dry cows. Grazing dry cows on a large bare paddock carries similar risk. Cows are back-fenced off the re-growth area as they move through the paddock to prevent this and minimize sward damage.
Dry cow minerals
Dry cows are offered bucket-lick minerals during the far-off, leaderfollower grazing period. These are adequate to build up trace mineral reserves but will not provide adequate Mg to close-up cows. When cows enter the calving paddock mineral licks are provided, but in addition 100g of high Mg (25%) powder mineral per cow is supplemented daily. This is mixed with 1kg barley as a carrier and fed out in troughs once per day. This also provides an opportunity to inspect cows for signs of calving.
Under this system the majority of Autumn cows calve trouble-free outdoors during September and early October, thereafter conditions may necessitate drafting of remaining cows indoors on point of calving. This can be simplified by placing temporary fence around meal troughs to draft cows at feeding each day.
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