Investigations on feed intake behaviour of ad libitum fed group housed pregnant sows at tube feeders

Investigations took place in 3 farms with group sizes of 8 to 32 sows and a d libitum feeding at tube feeders with energy reduced feed (9.3 to 9.6 MJ M E/kg) using unmolassed sugar beet chips (10%), straw meal (25%) resp. in ra tion. Behavioural observations have been made with infrared video technique and time lapse video recording always during 24 hours. Individual duration of staying at trough in 24 hours and percentage of time feeding places wer e used by different number of sows per hour during 24 hours were analysed b y OBSERVER/Video-Tape-Analysis-System. Large individual differences in duration of staying at trough in 24 hours o ccurred between sows of a group with means from 1.8 to 18.0% although all s ows had free access to always available food. Behavioural investigations ha ve shown that several sows did not come to trough over 24 hours without sho wing clinical signs of a disease. At the same time this is a hint at the pr oblem of disease control of ad lib fed sows especially in large groups. Analysing the percentage of time feeding places were used by different numb er of sows a biphasic dynamics of feed intake behaviour of ad I ib fed sows was found with a peak in the morning (7 to 10 a.m.) and a more distinct pe ak in the afternoon (3 to 7 p.m.).