Agriculture Reference
In-Depth Information
milk, 31% of the beef and 46% of the sheep and goat meat had to be sold to conventional
outlets often at a lower price than that received for organic produce (Hamm and Gronefeld
2004).
Animal disease patterns: an oeriew
Good animal health and welfare is an explicit goal of organic farming. The term 'health' is
often used to indicate 'no diseases', but covers many other components (see
Chapter 8
). We
focus here on the disease problems that organic livestock production faces. We will approach
this issue by giving a short overview of research findings related to disease levels, mostly in
Europe. Organic livestock production has developed and changed in several ways over the past
few years (e.g. standards, attitudes, infrastructure), which should also be kept in mind when
organic research results are evaluated.
At the end of the chapter, we focus on the human role in organic livestock production, and
suggest how to incorporate the principles of health care in a more structured manner.
The background to changes in disease patterns associated with conversion to organic pro-
duction mostly relate to different housing conditions, feeding and outdoor production, treat-
ment criteria, or changes in farmers' attitudes and perceptions. All these changes can have
both positive and negative effects on disease patterns, and since the conversion period may be
characterised by changes and new ways of managing the herd, the conversion itself may have a
negative impact on the disease situation in the herd. Lund and Algers (2005) cautiously con-
cluded, based on a literature review of peer-reviewed journal articles on animal health and
welfare aspects in organic farming, that apart from parasite-related diseases, health and welfare
in organic herds in general are the same or better than in conventional herds. Regarding para-
sitic diseases, Thamsborg
et
al
. (1999) concluded that good prospects are expected for accepta-
ble parasite control for organic farming systems.
Prominent disease problems are similar for organic and conventional dairy herds: mastitis,
lameness and metabolic disease in adult cattle and internal parasite infections in young
animals. The extent of these problems seems to vary more among farms than between organic
and conventional farming. Mastitis has been recognised as the main animal health problem in
organic dairy herds. Disease incidence in general appears to be similar, and occasionally higher
compared with conventional production (Thamsborg
et
al
. 2004, based on several European
studies from 1988 to 2000). Studies from Norway (Ebbesvik and Løes 1994, Hardeng and Edge
2001), Sweden and Denmark (Vaarst and Enevoldsen 1994) in the 1990s found a lower inci-
dence of treated cases of clinical mastitis in organic than in conventional dairy herds. Hovi
and Roderick (1999) found that 50% of surveyed organic herds in England and Wales had rela-
tively high levels of dry period mastitis compared with conventional farms, which had almost
none. The differences between these findings could be associated with the widespread use of
antibiotics in dry cow therapy in conventional herds in the UK. Comparative data on lameness
and claw lesions are not conclusive. Offerhaus
et
al
. (1993) showed that lameness was more
prevalent on conventional farms. Vaarst (1995) and Vaarst
et
al
. (1998b) found no major differ-
ences between systems, whereas a more recent Danish survey showed a higher incidence of
recorded claw and leg disorders in recently converted organic farms (Danish Cattle Advisory
Board 1998). In addition, a considerably higher incidence of liver abscesses has been detected
in Danish organic compared to conventional dairy cows, probably caused by rumen acidosis
due to higher grain proportions of feed ration and more grazing (Jørgensen
et
al
. 2005).
Gastrointestinal parasites and coccidia may cause problems in organic dairy herds espe-
cially among young calves, and lungworm disease can be a problem among dairy cows, partic-
ularly in newly converted herds where the animals have not been on pasture previously. Most
of these diseases can be controlled by appropriate management routines (Svensson
et
al
. 2000),
