Fasciola hepatica seroprevalence in Northern German dairy herds and associations with milk production parameters and milk ketone bodies.

Infections with the liver fluke Fasciola hepatica remain a serious problem in dairy herds causing significant production losses. In sheep, a strong relationship between F. hepatica infections and an increase in serum ketone bodies due to reduced feed intake and liver damage was demonstrated. We hypothesized that F. hepatica infections might contribute to an increase in milk ketone bodies in dairy herds. Thus, the objective of the study was to estimate the association between F. hepatica bulk tank milk (BTM) antibodies and milk production parameters (milk yield, milk protein, fat yield), somatic cell count (SCC) and the milk ketone bodies ß-hydroxybutyrate (BHB) and acetone, inferred from Fourier transform infrared (FTIR) spectrometry, via linear mixed model analysis. A further aim was to follow up the F. hepatica seroprevalence in dairy herds in the northern German region East Frisia. We collected BTM samples between October and December from 1022 herds in 2017 and 1318 herds in 2018. Overall, 33.1 % of the herds tested positive in 2017 and 37.0 % in 2018, showing decreased F. hepatica seroprevalences compared to prior seroprevalence studies in the same region in 2010, 2008 and 2006 (> 45 % positive herds). We estimated a significant negative association (P < 0.001) between herd F. hepatica infection category and average milk yield with a loss of -1.62 kg per cow per day in strongly infected herds compared to BTM ELISA negative herds. Moreover, F. hepatica infection category had a significant effect on herd average milk protein and fat yield (P < 0.001), showing a decrease of 0.06 kg for both parameters from BTM ELISA negative herds to strongly infected herds. No significant association with milk SCC was found (P = 0.664). Regarding ketone bodies, we estimated significant higher average BHB values in strongly infected herds compared to the other three infection categories in the model analysis (P = 0.002). The association between F. hepatica infection category and acetone values was not significant (P = 0.079). Besides primary ketosis, fasciolosis should be considered as differential diagnosis in dairy herds with increased BHB values.

May K ，Bohlsen E ，König S ，Strube C ... -  《-》

Patent infections with Fasciola hepatica and paramphistomes (Calicophoron daubneyi) in dairy cows and association of fasciolosis with individual milk production and fertility parameters.

Infections with the liver fluke Fasciola hepatica may result in considerable economic losses in the dairy livestock industry worldwide. Infections have been associated with detrimental impacts on milk production and milk quality as well as reduced fertility. However, most related data rely on examinations on herd level and the rather few studies on individual cow level are based solely on antibodies as measure for F. hepatica infections. This entails the risk of including false-positives as anti-F. hepatica antibodies persist for months even if the infection is cleared. Therefore, the presented study aimed to overcome this issue by assessing the association between F. hepatica infections measured via faecal egg counts (FEC) and milk production as well as fertility parameters in individual dairy cows. In total, 2006 faecal samples from 1166 Black and White dairy cows from 17 small and medium-sized German grassland farms were examined in July and September 2015. The relationship between patent F. hepatica infections and the milk production parameters milk yield, milk protein content, milk fat content and somatic cell score (SCS) was assessed in a linear mixed model using test-day records of individual cows. Patent F. hepatica infections were found on 35.3% (7/17) of farms with an individual cow prevalence of 10.1% (97/963) in July and 9.1% (95/1036) in September. Patent rumen fluke infections were detected on 17.6% (3/17) farms with an individual cow prevalence of 0.4% (4/963) in July and 0.7% (9/1036) in September. No significant association was found between F. hepatica infection status and either SCS as an indicator of udder health or milk production parameters, despite 0.06 and 0.10% lower values for milk protein and fat content in patently infected cows. Linear mixed models and generalized linear mixed models were established to estimate the impact of fasciolosis on the fertility parameters calving to first service (CTFS), calving interval (CI), success in first insemination (SFI) and 56-day nonreturn rate (NRR56). A significantly higher average CTFS of 4.69 days was detected in F. hepatica infected cows (P = 0.025), but no significant relationship was found for the other fertility parameters.

May K ，Brügemann K ，König S ，Strube C ... -  《-》

Bulk milk-estimated seroprevalence of Fasciola hepatica in dairy herds and collecting of risk factor data in East Frisia, northern Germany.

The liver fluke Fasciola (F) hepatica is one of the most important trematodes in cattle farming worldwide. Fasciolosis in dairy cows is leading to production losses due to decreased milk yield, liver condemnation and impaired reproduction. The treatment of dairy cows is unsatisfactory, because available drugs are either effective against adult flukes only or have long withdrawal times or in some countries may not be used at all. In the present study the prevalence of F. hepatica in dairy farms located in East Frisia, which is part of the federal state Lower Saxony, was investigated. East Frisia is considered a high risk area for Fasciola hepatica infections, because of its coastal location, high precipitation and moist pastures. About 750 bulk milk samples were collected in January and November 2006 and analysed for F. hepatica antibodies using the Pourquier ELISA. In addition, questionnaires, which were answered by 260 of the participating farmers, were evaluated to analyse management-related factors associated with fasciolosis. In January and November, 52.1% and 53.6% of the bulk milk samples, respectively, showed positive results. Thereby, 88.1% of the examined farms showed an unchanged infection status, whereas 6.2% of the farms became seropositive during the grazing season and 5.8% of the dairy herds turned seronegative. Statistical analysis revealed a significant negative association between average annual milk production and the frequency of infections with F. hepatica.

Kuerpick B ，Fiedor C ，von Samson-Himmelstjerna G ，Schnieder T ，Strube C ... -  《BERLINER UND MUNCHENER TIERARZTLICHE WOCHENSCHRIFT》

Association between milk yield and milk anti-Fasciola hepatica antibody levels, and the utility of bulk tank milk samples for assessing within-herd prevalence on organic dairy farms.

Fasciola hepatica is an important disease of livestock that is responsible for substantial economic losses worldwide. Estimates of the impact of infection on milk yield vary, likely reflecting different geographical locations, farm-level management, and diagnostic methods. Measuring anti-Fasciola antibodies on bulk tank milk (BTM) by ELISA provides a convenient herd-level diagnosis, but the utility of this test remains unclear. Therefore, we evaluated the utility of BTM ELISA test results in Danish organic dairy farms, including estimating the association between 305 day energy corrected milk yield (305d ECM) and F. hepatica infection both at individual and herd level. BTM samples from 218 organic farms were analysed using IDEXX ELISA and subsequently the farmers were interviewed during spring 2016 with the aim of characterising their management practices. The corresponding farm-level production data covering the period 2014-2017 were collected from the Danish national cattle registry. In the following year, 284 individual milk samples (4-7 per herd) along with BTM samples were collected from a subset of the same herds (n = 55). Linear mixed models were used to estimate the association between milk production and ELISA value at both individual and farm levels, and a generalised additive model was used to assess the relationship between within-herd prevalence and BTM ELISA. A dichotomised BTM result with positive outcome was associated with a reduction of 580.5 kg in average 305d ECM, and a positive outcome on individual-level ELISA was associated with a 919.5 kg reduction in milk yield for cows in their third or later lactations. A strong relationship between quantitative BTM ELISA sample to positive percentage (S/P%) and apparent within-herd prevalence based on dichotomised individual-level milk ELISA was also observed, although this relationship was non-linear in nature. We conclude that a useful indication of the within-herd prevalence of infection can be obtained from BTM ELISA following categorisation as negative, low, medium or high according to S/P% cut-offs of approximately 30, 80, and 150. This approach represents a cheap and useful diagnostic tool for monitoring the long-term success of control strategies for F. hepatica infections on a dairy farm.

Takeuchi-Storm N ，Thamsborg SM ，Enemark HL ，Boes J ，Williams D ，Denwood MJ ... -  《-》

Risk factors for the presence of Fasciola hepatica antibodies in bulk-milk samples and their association with milk production decreases, in Cuban dairy cattle.

Worldwide, Fasciola hepatica infection causes high production losses in the livestock industry. Recently, studies have analyzed the association between measurements of F. hepatica infection intensity and herd management practices. The aim of the present study, the first of its kind in a subtropical region, was to evaluate associations between F. hepatica bulk-tank milk ELISA results with herd management factors and milk yield in dairy herds, in Camagüey, Cuba. The SVANOVIR® F. hepatica-AB ELISA was used to measure F. hepatica antibody levels in a random sample of 516 dairy herds during the period of May-July of 2014. Farm management practice data were collected using a questionnaire. With 82% of the herds testing positive, the results indicate that F. hepatica is very widespread in this area. Reductions in milk production of 18 and 32% were observed in herds with Optical Density Ratios (ODR) of 0.3-0.6 and > 0.6, respectively, when compared to herds with ODR <  0.3. Overall, the longer the milking cows were put out to pasture, the higher the levels of anti-parasite antibodies. Co-grazing with sheep and goats also significantly increased the risk of high ODR. Our data show a widespread occurrence of the parasite as well as a major potential impact of the infection on the Cuban development goal of becoming self-sufficient in milk production. Our risk factor analysis suggests that the prevention of infection around water sources, and the separation of cattle from small ruminants could be useful control measures. This is the first epidemiological survey of F. hepatica abundance, and associated reductions in milk yield, in dairy herds in Cuba.

Arenal A ，García Y ，Quesada L ，Velázquez D ，Sánchez D ，Peña M ，Suárez A ，Díaz A ，Sánchez Y ，Casaert S ，van Dijk J ，Vercruysse J ，Charlier J ... -  《BMC Veterinary Research》