title: Productive and reproductive performances of dairy cattle herds in Treviso province, Italy (2009-2012): an assessment of the potential impact of Schmallenberg virus epidemic.
abstract: BACKGROUND
  Schmallenberg virus (SBV) has spread across Europe since mid-2011, causing unspecific and transitory symptoms in ruminants and congenital malformations in their offspring. Evidence for the impact of SBV on cattle (re)productive performance is limited. Using a comprehensive data set from a SBV-affected province in North-East Italy, this study aimed at assessing the potential impact of SBV emergence on 11 productive and reproductive performance indicators of dairy cattle herds, accounting for weather conditions and other herd-level factors that could also influence these indicators.
  
  
  RESULTS
  A total of 127 farms with an average of 71 cows per farm (range 29-496) were monitored monthly from January 2009 to June 2012. Mixed-effects linear models for longitudinal data were used to assess the average variation in herds' performance indicators over semesters (Jan-Jun 2009, Jul-Dec 2009, Jan-Jun 2010, Jul-Dec 2010, Jan-Jun 2011, Jul-Dec 2011, Jan-Jun 2012) and trimesters therein. Taking the second semester of 2011 as reference, significant decreases in the average lactation length (-6 days, on average) and calving-to-conception interval (-4 days, on average) were observed relative to the same semesters of the years 2010 and 2009, respectively. Similarly, during the last trimester of 2011, which is most likely to cover the SBV infection period in the study area, there was an average decrease of -4 days (lactation length) and -7 days (calving-to-conception interval) compared to the same trimesters of the years 2010 and 2009, respectively. However, the observed decreases actually represent a positive outcome that is not as such imputable to SBV emergence, but rather reflects other beneficial changes in farm management. None of the other indicators showed significant variations, confirming the relatively mild expression of SBV infection in cattle.
  
  
  CONCLUSIONS
  Although the emergence of SBV might have significantly affected the (re)productive performance of some individual farms, we concluded that overall at the province level there were no significant variations attributable to SBV, at least not in a way that would lead to negative effects on farm profitability.
authors.affiliation: Istituto Zooprofilattico Sperimentale delle Venezie (IZSVe), Viale dell'Università 10, 35020, Legnaro, (Padua), Italy. mtoson@izsvenezie.it.
authors.forename: Marica
authors.initials: M
authors.lastname: Toson
authors.affiliation: Istituto Zooprofilattico Sperimentale delle Venezie (IZSVe), Viale dell'Università 10, 35020, Legnaro, (Padua), Italy. lapo.mughini.gras@rivm.nl.|National Institute for Public Health and the Environment (RIVM), Centre for Infectious Disease Control (CIb), PO Box 1-3720, BA, Bilthoven, The Netherlands. lapo.mughini.gras@rivm.nl.
authors.forename: Lapo
authors.initials: L
authors.lastname: Mughini-Gras
authors.affiliation: Istituto Zooprofilattico Sperimentale delle Venezie (IZSVe), Viale dell'Università 10, 35020, Legnaro, (Padua), Italy. kcapello@izsvenezie.it.
authors.forename: Katia
authors.initials: K
authors.lastname: Capello
authors.affiliation: Istituto Zooprofilattico Sperimentale delle Venezie (IZSVe), Viale dell'Università 10, 35020, Legnaro, (Padua), Italy. lgagliazzo@izsvenezie.it.
authors.forename: Laura
authors.initials: L
authors.lastname: Gagliazzo
authors.affiliation: Istituto Zooprofilattico Sperimentale delle Venezie (IZSVe), Viale dell'Università 10, 35020, Legnaro, (Padua), Italy. lbortolotti@izsvenezie.it.
authors.forename: Laura
authors.initials: L
authors.lastname: Bortolotti
authors.affiliation: Istituto Zooprofilattico Sperimentale delle Venezie (IZSVe), Viale dell'Università 10, 35020, Legnaro, (Padua), Italy. mmazzucato@izsvenezie.it.
authors.forename: Matteo
authors.initials: M
authors.lastname: Mazzucato
authors.affiliation: Istituto Zooprofilattico Sperimentale delle Venezie (IZSVe), Viale dell'Università 10, 35020, Legnaro, (Padua), Italy. smarangon@izsvenezie.it.
authors.forename: Stefano
authors.initials: S
authors.lastname: Marangon
authors.affiliation: Istituto Zooprofilattico Sperimentale delle Venezie (IZSVe), Viale dell'Università 10, 35020, Legnaro, (Padua), Italy. lbonfanti@izsvenezie.it.
authors.forename: Lebana
authors.initials: L
authors.lastname: Bonfanti
mesh_terms: D000818:Animals; D002044:Bunyaviridae Infections / Q000453:epidemiology / Q000662:veterinary*; D002417:Cattle; D002418:Cattle Diseases / Q000821:virology*; D003612:Dairying; D058872:Epidemics / Q000662:veterinary*; D005260:Female; D007558:Italy / Q000453:epidemiology; D016851:Orthobunyavirus / Q000302:isolation & purification; D012098:Reproduction / Q000502:physiology