The economic and logistical consequences of using an automatic milking syst
em (AMS) on a dairy farm in the UK in place of the conventional dairy parlo
ur are examined. A three-phase discrete simulation model is combined with a
n economic analysis for a range of real farms, herd size of 85-95, and then
one of these farms is selected and a sensitivity analysis is conducted. Th
e model is able to simulate milking for cows housed all-year and those that
are to be fetched from fields. The model simulates the cows' yield and mov
ement throughout the year, according to their individual lactation curves.
The costs and benefits of an AMS for all-year voluntary presentation, for a
ll-year manually fetched (from fields and barn) and for a combination of vo
luntary presentation from barns in winter, and manually fetched from fields
in summer are examined. An analysis of the efficiency of the robot, i.e. t
ime for robot to attach teat cups, time for cow to walk through the system
and the time that the robot is available to the cow, is conducted. The util
ity of the robot is shown to be as important as robot efficiency and the co
ws will need to be motivated to use the robot for up to 22 h/d.
If dairy farmers are to switch from conventional milking to automatic milki
ng, they will need to decide how to deal with the increase in milk yield, b
y buying more quota or reducing their herd size. The costs of these two str
ategies are shown.
Using current prices and costs, a single-stall robot is compared to a multi
-stall robot. The sensitivity of robot cost and lifetime is shown. If the p
rice of quota is low, the robot is competitive for all-year voluntary prese
ntation with the conventional milking parlour, assuming that the robot can
be shown to have the same reliability. If automatic milking becomes more po
pular, the price of the system is likely to fall. Each reduction of pound 1
000 in the cost of the one robot and two milking stalls increases the annua
l relative profit of a farm (used as a baseline cost) by pound 147. (C) 199
9 Silsoe Research Institute.