Preliminary results suggest that May calving site selection of multiparous group housed dairy cows be influenced by the presence of amniotic fluids? Maria Vilain Rørvang, Mette S. Herskin and Margit Bak Jensen Department of Animal Science, Aarhus University, 8830 Tjele, Denmark Contact: maria.vilainrorvang@anis.au.dk Preliminary results suggest that choice of calving site may be affected by the presence of amniotic fluids from other cows Perspectives If these results are confirmed in larger studies, it may have implications for the management of cows around calving, where cows need to move from group housing to single calving pens. However, further studies are needed in order to verify the attractiveness of amniotic fluids for calving cows and to understand the underlying mechanisms. Amniotic fluids and the placenta contains olfactory cues for the establishment of mother-offspring bonds and maternal behaviour. On pasture, cows have been reported to calve in the vicinity of where their amniotic fluids were initially discharged. AIM: This pilot study investigated if the presence of amniotic fluids – left in the bedding as a result from the previous calving – affected the choice of calving site by group housed dairy cows. Materials and methods Results 1 In group 1, the calving interval ranged from 16-61h The first cow calved where her amniotic sac broke The four subsequent calvings took place within one cow length from the amniotic fluids from the first calving 2 groups of 5 multiparous Holstein cows Bleached for identification Familiar with each other 1 Animals Animals 1 Area within 1 cow length from where the amniotic fluids was spilled Grouped 2 days before first expected calving Access to large area (single and group pens) Ad lib. feed and water 24 h video surveillance Placement of a subsequent calving cow 2 2 Placement of the first calving, which was cleaned out fully Placenta removed after each calving Bloody and moist straw also removed and fresh added Heifer added when a cow was removed 2 In group 2, the calving interval ranged from 31-120h The first cow calved where her amniotic sac broke, and all bedding within 1 m was removed after calving. The second cow calved in another place, and the three subsequent cows calved within one cow length from her. Mean interval between calvings: 88 hours (range 31 to 120). Analysis 7 10 cows calved where amniotic fluids were present in the bedding. Cows did not select calving site randomly (χ2= 5.14, df= 1, P= 0.023). Procedures Birth place and time Place of bursting of amniotic sac One-sample proportion test in R version 3.2.3 Recordings and analysis