Modelling optimum switch date from twice- to once-daily milking
in dairy herds
V.C.F. WESTBROOKE, A.E. DOOLEY AND I. VETHARANIAM
AgSystems, AgResearch Limited, East St, Private Bag 3123,
Hamilton, New Zealand
E-Mail:
NZSAP 2003 Abstract No. 32
Proceedings of the New Zealand Society of Animal Production
63: 133-137
The production of a dairy herd was simulated at two different
stocking rates (3.4 cows/ha and 4.0 cows/ha) and two seasonal conditions
(an average and a dry Waikato summer). Cows were milked twice-daily
(TDM) for varying periods, before being switched to once-daily milking
(ODM) for the remainder of the lactation. Switching from TDM to ODM
during the milking season reduced the total production of the herd. With
3.4 cows/ha in an average summer, at a break-even value of labour of
$100 /milking ($200 /milking) the optimum switch-over date was January
13 (October 21); a dry season brought forward this date by approximately
two weeks. Increasing payout increased the break-even value of labour at
a given switch-over date. Under a commonly used farmer industry
guideline, break-even labour values under average (dry) conditions were
$53.47 /milking ($61.47) for 3.4 cows/ha and $36.07 /milking ($33.98) at
4.0 cows/ha. A stocking rate of 4.0 cows/ha switching to ODM after peak
production had a lower cash surplus than a 3.4 cows/ha stocking rate
with TDM due to additional ($30,000) feed costs with the higher stocking
rate. These results suggest a formal approach could be used to
complement industry guidelines in deciding when to switch from TDM to
ODM.
Keywords: NZSAPAB;
once-daily milking; labour efficiency; lactation; dairying;
stocking rate; modelling
Last Updated 8/07/2004
