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Silages constitute a major component of the feed ration for dairy cows, being a potential source of mycotoxins due to the possible contamination by filamentous fungi capable of producing these toxic compounds. In this study, samples of different kinds of silages collected from farms located in four regions of Spain, were analysed to evaluate the occurrence of aflatoxins (AFs) and Fusarium mycotoxins. Lactic acid bacteria and fungal populations as well as pH and water activity were also studied. Penicillium, Geotrichum and Monascus were the main fungi identified in all the silages examined. The incidence of AFs was low (10 % of positive samples). Fusarium mycotoxins were detected in 40 % of the samples and fumonisins (FBs) were the most commonly detected. Maize silage was the most heavily contaminated type of silage. Levels of mycotoxins detected in positive samples did not exceed the EU guidance values. The lack of relationship between Fusarium counts and its mycotoxin concentrations suggested that mycotoxin production possibly occurred pre-ensiling or immediately post-ensiling. Outcomes showed that mould growth and mycotoxin contamination in silages should be regularly monitored in order to minimize the exposure of dairy cows to contaminated feed., (Copyright © 2019 British Mycological Society. Published by Elsevier Ltd. All rights reserved.)

Bacteria from genera Listeria, Campylobacter and Arcobacter are potentially zoonotic pathogens for humans and they may be detected in dairy cattle farms. In this study the presence of these bacteria was considered in dairy cattle farms in Galicia (northwest of Spain). In the first part of the study, bulk tank milk samples were collected to determine the herd prevalences of Listeria spp. in 98 dairy farms. Additionally 83 silage samples and 97 faeces samples of lactating cows were collected. L. monocytogenes was detected in 6.1%, 9.3% and 6.0% of these samples, respectively. With regard to Campylobacter spp. and Arcobacter spp., 254 faecal samples were collected on 89 dairy farms. Campylobacter spp. was found with a herd prevalence of 36%. It was also confirmed in 20.5% of dairy cattle faecal samples. Arcobacter spp. was isolated in 68.5% of the farms and in 41.7% of faecal samples, with A. cryaerophilus being the most frequently identified species. The results related to the prevalence of the bacteria included in this study confirm their presence in high numbers in different types of biological samples from dairy farms, and suggest that more epidemiological studies regarding this bacteria need to be performed.

This cross-sectional study determined the prevalence of Listeria spp. in bulk-tank milk on dairy farms in the region of Galicia in northwest Spain. The aim was to identify management practices associated with the presence of Listeria spp. and possible effects on milk hygienic quality. A total of 98 farms was randomly selected on the basis of an expected prevalence of 6.5% for Listeria monocytogenes from 20,107 dairy farms in the region. Bulk-tank milk samples were obtained from 98 farms, fecal samples from lactating cows from 97 farms, and silage samples from 83 farms. Listeria monocytogenes was detected in 6.1, 9.3, and 6.0% of these samples, respectively. Statistical analyses confirmed the relationship between low silage quality (as indicated by high pH) and presence of Listeria spp. in silage (29.5 vs. 6.2% for pH above or below 4.5, respectively). Only milking system [tie-stall systems (28.6%) vs. parlor milking (10%)] and inadequately controlled milking order [yes (32.0%) vs. no (10.7%)] had statistically significant effects on management practices for increasing the risk of Listeria contamination of bulk-tank milk.