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22 May 2019
With many herds dried off now it’s time to think about dry cow feeding levels and requirements. The first thing I would encourage you to do is get the herd body condition scored (BCS). Use the DairyNZ app to score the cows it will give you the proportion of cows at each BCS. Use this information to draft cows into lighter and better conditioned cows so you can allocate feed efficiently.
Once the cows in are mobs we need to decide what to feed them. This is all about time to calving, as cows struggle to put weight on in the last month before calving and the quality of the pasture available can decline the further we get into winter. Autumn saved grass is typically around 11MJ ME/kgDM.
Example: Daily requirements of a 450 kg JXF cow, 12 weeks before calving and gaining 0.5 kg/day LWT (1/2 BCS in 30 days) at 11.0 MJ ME/kg DM.
Maintenance = 54 MJME
Pregnancy = 12 MJME
Liveweight gain (0.50 kg Lwt x 72 MJ) = 36 MJME
Total MJ ME required = 102
Total kg DM Eaten (102 divided by 11.0 ME) = 9.3 kgDM (Note: Diet ME required increased by 36 MJ ME from gain of liveweight)
Many farmers like to use square meters (m2) to allocate feed to cows as it makes it easier when changing the size of the mobs. This means for a 100ha farm on a 100 day round in the winter they can feed 1ha per day. If the average farm cover is 2200kgDM/ha and a stocking rate of 2.8 cows/ha, pre-grazing covers will need to be around 2800kgDM/ha. The calculation would be as follows:
2800 – 1200 residual = 1600kgDM/ha or 0.16kgDM/m2
1ha = 10,000m2 /280 cows = 35.8m2 day x 0.16 = 5.7kgDM/cow/day of grass.
This shows that we need to feed an additional 3.6kgDM/cow/day of supplements to top the diet up to the required level. Bear in mind that when feeding supplements it is worth checking the quality of the feed being fed and remembering if its lower ME content you will need to feed a greater amount to supply the required energy.
22 May 2019
23 kgs DM/day
2017 kgs DM/ha
% in milk
Crude Protein Level