Reproduction performances and conditions of group-housed non ...

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eating and lying behaviour, skin lesions and reaction in fear test were monitored at wean-
ing, at mating and/or three weeks after mating.
The study was conducted during an 11-month period from May 2003 to March 2004. The
timing of the registrations differed maximum 1.5 months between the herds. The 14 herds
were chosen to represent different layouts and management routines to ensure that any
found correlations could be transferred to apply in a broad spectrum of herds. The herd
sizes varied from 180 to 1000 sows. Feeding systems applied in the service unit were freeaccess
feeding and insemination stalls (11 herds), providing feed in long trough (1 herd),
floor feeding (1 herd) and biofix (1 herd). Feeding systems applied in the pregnancy unit
were floor feeding (5 herds), providing feed in long trough (2 herds) or feed dispenser (1),
Electronic Sow Feeding (2 herds), free-access feeding stalls (2 herds), individual feeding
stalls (1 herd) and biofix (1 herd). See Kongsted et al. (2004) for a more detailed description
of the farms.
2.2 Recordings
2.2.1 Reproduction and culling data
For each F-sow, weaning date, date for first mating, date for re-mating for the sows that
returned to oestrus after the first mating were recorded, farrowing date and the number of
born piglets (alive and stillborn). A sow was defined as pregnant after first mating if no
date for re-mating was noted. For culled sows, the date of culling and estimated culling
reason was recorded. The sows were only followed until re-mating, culling or farrowing.
Therefore, the number of culled sows did not include any re-mated sows.
2.2.2 Indicators
The timing of the recordings of the indicators was first of all chosen to give information
about the sows’ conditions from weaning to first mating and from first mating to three
weeks in pregnancy because these stages are believed to be the main periods of relevance
regarding reproduction performance (Kongsted, 2004ab). The motives for choosing the
respective indicators are discussed in Kongsted (2004a) and a more thoroughly description
of the recordings is provided in Kongsted et al. (2004).
Back fat gain and eating behaviour were used as indicators for feed intake. Back fat depth
was measured by means of a digital ultrasound back fat indicator LEAN MEATER ® (Baltic
Korn A/S, Naestved, Denmark) 65 mm from either side of the backbone at the 12 th (last)
and 10 th rib (conventionally known as P2-measurements) at weaning and three weeks after
mating. Eating behaviour was only registered in the eight herds with group feeding in the
pregnancy unit. For each sow, it was recorded whether the sow was eating or not for each
half minute during feeding three weeks after mating. Number of times the sow was not eat-
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