This section provides an introduction to health risks and current knowledge of disease patterns in organic cattle herds. Good Practice hints are also provided as an aid to reducing potential suffering as a consequence of restricted veterinary medicine is in organic farming. More detailed information on individual diseases can be found in the indexed Disease Management (Cattle) section and more general veterinary information can be found at Veterinary Management.
A review of health and welfare of dairy cattle has been completed as part of Defra Project (LINK HERE FOR COMPLETED DOCUMENT - DUE END Jun 08)
A change in disease patterns associated with conversion to organic production may be related to:
There may also be other influential factors, such as the introduction of new breeds or species mix.
Defra project The welfare of dairy cows on organic milk production systems (Project AW1020) (SAC, 2006) examined differences in risk of disease between organic and non-organic dairy farms. Generally, there was little difference between the two types of farming system. The following is a summary of the findings:
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A UK survey of organic cattle producers and their perceptions of animal health and welfare problems in their herds found that, in 34 surveyed organic dairy herds, the mean replacement rate was 21%. Mean calving interval was 380 days and average lactation yield was 4950 litres/305 days. The main reasons for culling were mastitis, lameness and infertility. Mastitis was the only disease that was ranked as a serious problem on the farms (Roderick and Hovi, 1999).
The same survey of 112 organic beef herds indicated very few animal health concerns. Infertility and calving difficulties achieved highest rankings in suckler herds, whilst in young stock external parasites, diarrhoea and mineral deficiencies were considered the most serious health issues.
In the same survey, answers from dairy farmers relating to routine use of vaccines revealed that only a minority of farmers used routine prophylactic vaccinations against lungworm (27%) or leptospirosis (19%). The majority of producers relied on clean grazing (54%) and/or mixed grazing (50%) strategies to control helminths in young animals. A small minority (8%) did not use any of these strategies. 77% of the dairy farmers used some type of foot health strategy, the majority adopting foot trimming (62%), with third of these also using footbaths. Over 60% of the farmers used a combination of antibiotics and homeopathy to treat mastitis, but none used antibiotic dry cow therapy. Some 25% of the farms did not use any udder preparation or post teat dipping in connection with milking. The beef producers also used mixed and/or clean grazing to control parasites, with 30% of the respondents using anthelmintics as well.
In a similar study, Halliday et al (1991) surveyed 54 organic farms (12 dairy producers) and found that the farmers perceived mastitis, milk fever, lameness and conception difficulties as the most common disease conditions in their herds. The report also gives detailed information on the use of alternative treatments of diseases and their efficacy as perceived by the farmers.
Weller and Cooper (1996) studied eleven UK dairy herds converting from conventional to organic production. They identified clinical mastitis as the main problem on most farms, with an incidence rate higher than national average, while the incidence of lameness, milk fever, ketosis and post-calving problems was lower than reported elsewhere in UK herds. The mean clinical mastitis incidence before and after conversion were reported as 40.5 and 45.8 cases/100 cows, respectively.
A survey of mastitis in 16 organic dairy herds in England and Wales found that mastitis incidence varied greatly between the organic farms. The overall results suggest that dry period mastitis is a problem in many farms and that the SCC levels are significantly higher than on matched conventional farms. Homeopathy was the main alternative to antibiotics in both treatment and prevention of mastitis on most farms. Average calving interval on the 16 organic farms was 387 days, and culling rate 17%. (Hovi and Roderick, 1999). See Mastitis for more information.
Most other publications on the subject of animal health and welfare in organic dairy herds originate from other European countries. The Danish Institute of Animal Science runs an extensive research programme on organic farming. The main emphasis of the research is on animal production, feeding and housing systems and nutrient flows on organic farms with livestock, but a considerable body of work is also being developed on dairy cow health (Vaarst, 1996; Vaarst, 1995; Vaarst et al 1993, Vaarst et al 1992; Vaarst et al, 1991). Vaarst found that the disease situation on 14 organic dairy farms was comparable with conventional Danish dairy farms, with a lower incidence of lameness and lower veterinary costs. Mastitis was again recognised as the main disease problem.
A 2 year study of 22 Norwegian organic dairy herds (Ebbesvik, 1993) revealed that although milk production was considerably lower than in conventional herds, the organic herds had a lower incidence of mastitis, milk fever and ketosis. Fertility rates and the mean age of culling were also higher than the national average. As a part of the same research project, Olesen (1996) studied the concentration of ketone bodies in the milk and blood of organically managed dairy cows and found that the levels were significantly lower than in conventional dairy cows. This suggests that the organic feeding regimes were successful in maintaining energy balance during lactation.
In an experimental study in Germany, 60 dairy cows were housed under similar environmental conditions and divided into two groups: one managed and fed according to organic standards and the other conventionally (Von Weber et al, 1993). No significant differences were detected in the health parameters, apart from higher somatic cell counts in the organically managed cows. The fertility parameters, however, were significantly more favourable in the organic group.
In the Netherlands, Offerhaus et al (1994) found lower incidence of lameness, ketosis and milk fever in organic dairy herds. Mastitis levels were similar to conventional farms.
While overall levels of health appear to be good in organic cattle, in some situations health issues such as liver fluke (MacNeidthe et al., 1997), parasitic gastro-enteritis (Younie, 1992), or ectoparasite control (Keatinge, 1997) may pose particular problems for organic production, although it has been shown that the strategies used by organic farmers to control gastrointestinal parasites were as successful as those used by non-organic farmers with no differences observed between organic and non-organic farms in the level of internal parasites (SAC, 2006).
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Areas where particular care is needed to avoid suffering in organic dairy herds due to the restrictions on conventional husbandry or treatment methods are:
Drying off cows without antibiotics and avoiding dry period mastitis: if dry cow mastitis becomes a problem on a farm after the withdrawal of antibiotic dry cow therapy, immediate action should be taken to assess the drying off methods used and the dry cow management implemented.
Trace element deficiencies due to non-supplementation, particularly in areas of inherent soil deficiencies: situation should be monitored carefully, and supplementation should be carried out when needed.
Energy deficiencies in high-yielding dairy cows on high-protein forage diets: condition scoring of early lactation cows should be routinely carried out, and any signs of energy deficiency should prompt a change in the feeding.
Treatment of injuries and disease without conventional veterinary medicinal inputs: an organic farm should have a clear policy on when to use, for example, antibiotics or analgesics to prevent further suffering or further spread of a disease, independent of the risk of the animal losing its organic status due to more than two treatments with veterinary medicinal products.
Special care should be taken to avoid any suffering caused by non-treatment or treatment with inefficacious therapies of diseased or injured animals. When new therapies are introduced to the farm, the efficacy should be carefully monitored and where little or no improvement is seen rapidly, a change of therapy form should be considered before undue suffering to the animal is caused. The safest procedure is to leave the judgment on whether the animal is suffering or not to the veterinarian.
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