Project aims
(English)
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We propose an additional epidemiological investigation on cows held in organic as compared with cows held in conventional farms in the cantons of BE, FR, NE, SO and LU. The primary goal is to test the hypothesis that cows held in certified organic dairy herds differ from those held in conventional farms not only with respect to nutrients fed and nutritional management, but also with respect to nutritional status, health status, reproductive performance, milk production, milk composition, frequency of mastitis, anti-biotic resistance of bacteria isolated from infected mammary glands, and presence of VETC in fecal samples and possibly in milk.
Variables to be measured:
- Nutrition and nutritional status: feed evaluation (feeds fed), BCS, body weight (tape measure-ment), metabolic profile (glucose, non-esterified fatty acids, b-hydroxybutyrate, albumin, urea, in-sulin-like growth factor-I, 3.5.3'- triiodothyronine concentrations in blood plasma), fat, protein, urea and acetone concentration in milk. These metabolic and endocrine profiles have been shown to provide the best biochemical indicators of energy and protein balance in dairy cows.
- Health status: metabolic diseases, organ diseases, mastitis (clinical; subclinical based on Cali-fonia mastitis test and somatic cell counts), other clinical diseases and preventive measures (rec-ords of farmers and veterinary practitioners)
- Production: milk yield (kg, fat, protein)
- Reproduction: interval from first to successful insemination, calving-to-conception intervals, con-ception rates calf production
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Abstract
(German)
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Dary cows in farms with organic and integrated production: management, feeding, production, reproduction and udder health
In a case-control study differences between 60 organic farms (OP) and 60 farms with integrated production (IP) were evaluated. Farms were located in the midland and prealpine zones and were a representative sample of the situation in the Canton of Berne, Switzerland. IP farms matched to OP farms were comparable in terms of community, agricultural zone and cow density. Depending on the number of cows/farm, 5, 8, or 13 cows were selected, resulting in 970 multiparous cows that were studied at about 30 days ante partum, and 30 and 100 days post partum (visits 1, 2 or 3). At each visit, body weight, type, and amounts of provided feeds and farm management were documented. Blood and fecal samples were collected at the second visit.. Characteristics of OP and IP farms were as follows: mean size = 17.7 and 16.9 ha; mean dairy cow number = 14.0 and 15.5; mean annual milk quota = 65'900 and 70'000 kg; loose housing systems = 18 and 7% (P=0.053); outside paddocks = 98 and in 75% (P<0.05); Simmental x Red Holstein cows = 87 and 75 %; Holstein cows = 42 and 60%. In winter rapeseed or soya protein and succulent feeds were more often fed (red holsteinP>0.1) in IP than OP farms. Main causes for cow replacements in OP and IP farms were fertility disorders (45 and 45%), age (40 and 42%), sale (30 and 37%) and udder health (35% and 13%; P<0.01). Regular teat dipping after milking was performed in 25% and 43% (P<0.05) in OP and in IP farms. Blanket dry cow treatments were performed in 45% of IP, but not in OP farms (because not allowed). In the lactation preceding the actual study in OP and IP farms the 305-day energy-corrected milk yield was 5'767 and 6'331 kg (P<0.005) and somatic cell counts (SCC) in milk were 118'000 and 115'000/mL. In the actual lactation, at the second and the third visit, SCC were 104'000 and 92'000/mL in OP farms and 73'000 and 80'000/mL in IP farms. Reproduction data during the preceding lactation were similar and on a high level in both OP and IP farms. Alternative veterinary treatments in OP and IP farms were used in 55 and 17%. Thus, OP and IP farms differed in several respects.
Dairy cows in farms with organic and integrated production: subclinical mastitis
Subclinical mastitis is one of the most costly diseases in dairy production and is more frequent in farms with organic production (OP) than in farms with integrated production (IP). Epidemiological studies comparing chronic mastitis in OP and IP farms are lacking. Based on that we have investigated 970 cows in 60 randomly selected OP farms and 60 comparable IP farms in the canton of Berne to test the hypothesis that the prevalence, risk factors and patterns of udder pathogens in OP and IP cows are different. California Mastitis Tests (CMT) were performed at around 31 d p.p. in 483 OP and 487 IP cows and at around 102 d p.p. in 419 OP and 421 IP cows. Cows with CMT =1+ in one quarter but without clinical signs of mastitis were considered to have subclinical mastitis. Of quarters with CMT =2+ a milk sample was taken for bacteriological follow-up. Somatic cell counts (SCC) were available from breeder organisations. Cow-level prevalences of subclinical mastitis for visits 2 and 3 (31 and 102 d p.p.) were 39 and 40% in OP farms and 34 and 35% in IP farms, resp. Quarter-level prevalences of mastitis were 15 and 18% in OP farms and 12 and 15% in IP farms, resp. The median SCC (in 103 cells/mL milk) at 31 and 102 d p.p. were 42 and 45 in OP cows and 28 and 36 in IP cows. Prevalences of Staphylococcus aureus and other staphylococci were higher in IP than OP farms, whereas prevalences of Streptococci other than Streptococcus agalactiae and Corynebacterium bovis were higher in OP than in IP farms. Breed, teat or udder injuries, no antibiotic dry cow therapy, and SCC before drying off were identified as significant risk factors for the development of subclinical mastitis. In conclusion, there was a higher number of subclinical mastitis in the first 100 d of lactation in OP than IP farms. Some of the found risk factors were strongly related to the two different farming systems. However, the farm type was less important than cow and management factors, albeit the farm type is confounded with differences in management factors. The separate analysis of risk factors for OP and IP cows showed, that there are - besides common risk factors such as breed and antibiotic udder treatment after calving - specific effects. Thus, in OP farms the average farm SCC as well as alternative medication and in IP farms the antibiotic dry cow therapy and nutritional aspects may be of special importance.
Dairy cows in farms with organic and integrated production: antibiotic resistance of bacteria isolated from cows with mastitis
Studies in Swiss farms with organic production (OP) have shown that bacteria isolated from cows with mastitis are resistant to many antibiotics (Prevent. Vet. Med. 44, 2000, 205-220). This was surprising because there is basically restrictive use of antibiotics in OP farms and it may be therefore expected that antibiotic resistance in OP cows is low. We have therefore analyzed antibiotic resistance of bacteria isolated from udders with subclinical mastitis of cows held in OP farms as compared with cows held in farms with integrated production (IP). In 60 OP and 60 IP farms in the canton of Berne, 483 and 487 cows, resp., were studied at 21-43 d p.p. and 419 and 421 cows, resp., at 72-135 d p.p. for the presence of antibiotic resistant pathogens. California mastitis tests (CMT) were performed on each quarter. From CMT=2 quarters bacteriological cultures were were isolated, identified and tested. Quarter milk samples from 169 OP and 123 IP cows were screened: 127 samples with Staphylococcus (S.) aureus, 74 with S. other than S. aureus (S. epidermidis, S. xylosus, S. hyicus, Micrococcus sp.), and 90 samples with Streptococci (Sr.) other than Sr. agalactiae (Sr uberis, Sr. dysgalactiae). Antibiotic resistance of S. aureus from OP and IP cows differed numerically for chloramphenicol (20 and 6%), clindamycin (4 and 0%), erythromycin (9 and 0%), gentamycin (11 and 6%), oxacyllin (6 and 0%), penicillin (13 and 3%), quinupristin/dalfopristin (2 and 0%), tetracycline (2 and 0%), ceftiofur (2 and 0%) and for overall resistance (35 and 18%). Antibiotic resistance of S. other than S. aureus from OP and IP cows was numerically different for chloramphenicol (10 and 0%), gentamycin (5 and 0%), oxacyllin (26 and 42%), penicillin (32 and 47%), quinupristin/dalfopristin (5 and 0%), and tetracyline (5 and 0%), but overall resitance the antibiotic resistance was similar (47 and 53%). Antibiotic resistance of Sr. uberis from OP and IP cows differed numerically for chloramphenicol (16 and 11%), clindamycin (10 and 0%), enrofloxacin (42 and 22%), erythromycin (10 and 0%), gentamycin (53 and 33%), penicillin (5 and 11%) quinupristin/dalfopristin (5 and 0%), and overall resistance (79 and 44%). Antibiotic resistance of Sr. dysgalactiae from OP and IP cows differed numerically for enrofloxazin (33 and 75%), erythromycin (0 and 50%), gentamycin (22 and 25%), tetracycline (56 and 100%), and overall resistance (67 and 100%). Resistance against ³2 antibiotics of S. aureus and of S. other than S. aureus from OP and IP cows differed (17 and 3%; 21 and 42%, resp.). Antibiotic resistance was slightly higher among staphylococci from OP than IP cows, except for beta-lactam antibiotics, whereas antibiotic resistant of strepotococci was slightly higher in isolates from IP than OP cows. Overall, the frequency of antibiotic resistance did not significantly differ between OP and IP cows, but seemed to be strain-related. Importantly, none of the strains was resistant for Amoxyylin/Clavulanic Acid or Vancomycin. However, resistance to cephalosporins, erythromycin, gentamicin, and quinupristin/dalfopristin have emerged in these bacteria. Surveillance is now necessary to follow the evolution of antibiotic resistance in mastitis pathogens in order to avoid the emergence of multidrug resistant bacteria in an environment where they are the least expected, such as OP farms.
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Publications / Results
(English)
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The data were presented at a meeting for farmers involved in the study on OP and IP farms on Dec. 11, 2003 in Bern and at the Ann. Meeting of the Schweiz. Vereinigung für Tierproduktion in Zürich on March 3, 2004
and at the 12th Int. Conf. on Production Diseases in Farm Animals, East Lansing, USA, on July 19-22, 2004.
Rösch, Markus (2004): Dairy cows in Swiss organic and conventional farms: Comparison of management, feeding, production, reproduction and udder health. Inaugural-Dissertation, Vetsuisse Fakultät, Universität Bern, Schweiz.
Kuhnert, P., Dubosson, Ch.R.,, Roesch, M., Homfeld, E., Doherr, M.G., Blum, J.W. (2005): Prevalence and risk-factor analysis of Shiga toxigenic Escherichia coli in faecal samples of oganically and conventionally farmed dairy cattle. Veterinary Microbiology, 109, p. 37-45
Roesch, M.; Doherr, MG.; Blum, JW. (2006) Management, feeding, production, reproduction and udder health on organic and conventional Swiss dairy farms. Schweiz Arch Tierheilkd 148: 387-95.
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