Innovative Technology and Sustainable Development of Organic - 1.

535) in 2005 was 0.64 (DCF, 2005). High milk yield accompanied by stress is often mentioned as a
reason for increasing health problems. At CMS farms, milk yield explained 45% of the treatment
index, but no correlations between specific health indicators (such as mastitis) and milk yield were
found. Among AMS users, no correlation between milk yield and treatment index was found (R 2 <
0.01). The treatment of mastitis explicitly comprises the major part of all veterinary treatments for
AMS and CMS farms. The sum of treatments primarily influenced by grazing was 0.70 per cow per
year for AMS farms and 0.63 for CMS farms. One would expect that the extra time spent outside by
CMS herds (2,083 h versus 968 h per year) would show positive health effects (Somers et al., 2003;
Munksgaard and Søndergaard, 2006), but this was not the case.
At AMS farms 3.9% of the cows died per year. The average for all organic herds in 2005 was 4.1%.
Among the 9 CMS farms, 2.7% of the cows died in 2005. Thomsen et al. (2006) found a positive
relation between “loser cows” and zero grazing, and a higher death rate among “loser cows”. Much
longer grazing time (Table 4) among CMS users, did not influence the death rate consistently (P =
0.16).
Labour
In this study, AMS farms used on average 3 min per cow per day, whereas CMS farms used on average
5.3 min per cow per day (P < 0.001); a saving of 2.3 min per cow per day. Extension services in
Denmark registered that 15 months after introduction of an AMS, farm management had adjusted
totally to the new situation. In addition, most AMS farms have increased their herd size at the same
time as they invested in AMS, and previous labour time registrations have found that larger farms
saved relatively more time when using AMS. This could not be supported by our results (Fig. 2).
Minutes per cow per day
10
9
8
7
6
5
4
3
2
1
0
40 60 80 100 120 140 160 180
Herdsize
AMS CMS
Fig. 2. Labour time related to herd size for organic dairy farms using automatic milking systems
(AMS) and conventional milking systems (CMS).
Thesis Frank W. Oudshoorn 53