Productive and reproductive performances of dairy cattle herds in Treviso province, Italy (2009–2012): an assessment of the potential impact of Schmallenberg virus epidemic

Table 2 Adjusted estimates of the effects of semester on the average lactation length and average calving-to-conception interval of 127 dairy cattle herds of Treviso province, Italy, obtained from the final mixed-effects linear models with first order autoregressive covariance structure fitted to monthly measurements (January 2009 to June 2012)

Semester	Average lactation length (days)^a				Average calving-to-conception interval (days)^b
Semester	Least square mean†	Standard error	Coefficient	p-value	Least square mean†	Standard error	Coefficient	p-value
Jan-Jun 2009	203.50	2.13	7.65	0.0002	161.20	2.63	1.57	0.4448
Jul-Dec 2009	199.27	2.11	3.41	0.0671	163.72	2.62	4.09	0.0295
Jan-Jun 2010	202.21	2.03	6.36	0.0003	160.79	2.55	1.16	0.4923
Jul-Dec 2010	202.11	2.07	6.26	<0.0001	161.09	2.59	1.46	0.3077
Jan-Jun 2011	200.87	2.04	5.02	<0.0001	159.49	2.57	−0.14	0.8899
Jul-Dec 2011	195.85	2.12	Ref.	-	159.63	2.64	Ref.	-
Jan-Jun 2012	199.97	2.25	4.12	0.0042	159.98	2.72	0.35	0.7870

^aEstimates are adjusted for variables 6 and 12–18 and for mean temperature (see Tables 1 and 3), all included as fixed effects. Random effects were set at the farm level and used sinusoidal terms for seasonal control
^bEstimates are adjusted for variables 12–18, and for mean temperature (see Tables 1 and 3), all included as fixed effects. Random effects were set at the farm level and used sinusoidal terms for seasonal control
†Also referred to as marginal means, are the means after controlling for the other covariates included in the models

ISSN: 1746-6148