| dc.description.abstracteng | Conventional pig farmers and more particularly their pigs face many challenges throughout
different production stages that can alter the welfare and health of the animals and impair the
farmers economy and motivation in the long run. In Germany, all pig production stages are
regulated but these regulations are seen increasingly critical by different stakeholders as they
outline only minimum husbandry and management standards. On one hand, first
amendments of the “Animal Welfare Livestock Husbandry Ordinance” (German: Tierschutz-
Nutztierhaltungsverordnung), that for example decrease the duration of continuous
confinement of lactating sows or prohibit the castration of piglets without anaesthesia, and on
the other hand, the introduction of so-called animal welfare labels for livestock products, show
both the willingness by government, trade and customers to improve husbandry conditions
but it also increases the urge for substantiating research, as some problems like aggressive
interactions at regrouping and tail-biting during rearing and finishing period are still unsolved
for conventional housing practices.
The objectives of this dissertation were to investigate the effects of different housing systems
during suckling, rearing and finishing period and of different sire breeds on the behaviour
and performance of growing and finishing pigs. In particular, the aim was to study whether
loose-housing of lactating sows and their litters (single and group housing), reduced
regrouping events (single-phased vs. two-phased rearing and/or fattening) or the use of
traditional sire lines could improve the well-being of rearing and fattening pigs in terms of
reducing skin lesions, tail lesions, tail losses, serum cortisol levels and maintain or at best
increase average daily gains, especially for undocked pigs.
Research Article One studied how farrowing and rearing systems affect skin lesions, serum
cortisol, and aggressive behaviour as indicators for weaning stress of piglets. Therefore, 3144
piglets were weaned between May 2016 and March 2018 from three different farrowing
systems: farrowing crates (FC), single-housing free-farrowing pens (FF), and group housing
of lactating sows and litters (GH). After weaning and regrouping, the piglets were moved to
conventional rearing pens (conv; 5.7 m2) or to so-called wean-to-finish pens (w-f; 12.4 m2). One
day after weaning, the piglets’ behaviour was observed and the animals were assessed for skin lesions. One week before and one day after weaning the piglets were blood sampled in order
to analyse the individual difference in serum cortisol. Significantly more piglets raised in FC
and FF had moderate and severe skin lesions than piglets from GH. Also, piglets born in GH
showed lower differences in serum cortisol, and fought less and for shorter durations than
piglets born in FC and FF. Greater cortisol differences and significantly longer fights could be
found in piglets that were weaned into w-f pens compared to piglets in conv pens. The first
research study concluded, that group housing during the suckling period reduced the
weaning stress for piglets with regard to skin lesions, serum cortisol, and aggressive
behaviour. The greater space allowance of wean-to-finish pens showed no benefits concerning
the studied parameters compared to the space allowance of conventional rearing pens.
The first research article showed the potential of alternative housing systems for weaning
stress, but no long-term effects were investigated, especially in regard to the housing of
undocked pigs. The aim of Research Article Two was to present practicable alternatives to
stressful weaning and tail-docking. Therefore, 1106 pigs were weaned from: conventional
farrowing crates (FC), free-farrowing pens (FF), or group housing of lactating sows (GH) into
either conventional rearing pens (Conv) or the piglets remained in their farrowing pens for
rearing (Reaf). Batchwise, the tails of the pigs were docked or left undocked. For this study, all
pigs were relocated and regrouped for the fattening period. Starting one day after weaning,
the pigs were assessed weekly for tail lesions and losses and every two weeks during rearing
period and every four weeks during fattening period for skin lesions. The average daily gain
was calculated separately for the rearing and fattening period. The results showed that
significantly less Conv-GH pigs had skin lesions than Conv-FC and Conv-FF pigs after
weaning. After the regrouping for fattening, significantly less Reaf-GH pigs had skin lesions
than Conv pigs, Reaf-FC and Reaf-FF. While the incidence of tail lesions of undocked Conv
pigs reached its peak in week 4 (66.8 %), tail lesions of undocked Reaf pigs reached their
maximum (36.2 %) two weeks later. At the end of fattening, almost all of the undocked Conv
pigs (99.3 %) and less than half of the undocked Reaf pigs (43.1 %) endured tail loss. To
conclude, the group housing of piglets during suckling period reduced the incidence of skin
lesions. The incidence of tail lesions and tail losses of undocked pigs could be significantly
reduced by rearing in the farrowing pen. Moreover, no housing system affected the
performance negatively.
As research article one and two revealed promising effects of the housing systems on the
occurrence of injurious behaviour, i.e. on the incidence of skin and tail lesions and tail losses,
the focus of Research Article Three was then to investigate the potential of different local,
traditional sire breeds for the behaviour and performance of rearing pigs. Therefore, hybrid
sows (BHZP Landrace x BHZP Large White) were paired with either Swabian-Hall (SH),
Bentheim Black Pied (BB) or BHZP-Piétrain (Pi) boars. In total 1561 piglets were weaned of
which tails were either left intact (43.5 %) or docked (56.5 %), and all male piglets were
castrated. The piglets were housed conventionally on fully slatted plastic floors in mixed-sex
groups. Starting on the first day after weaning, skin lesions were scored once and tail lesions
and losses were scored weekly until the end of rearing. Also, the average daily gain was
calculated for the rearing period and the activity behaviour was analysed for focus pens. The
results showed that significantly fewer BB pigs had severe skin lesions on the front body than
SH or Pi pigs. Moreover, significantly more BB pigs were assessed with no tail lesions and tail
losses for the first four weeks of the rearing period, compared to SH and Pi pigs but these
significant differences dissolve in the last four weeks of rearing. However, numerically more
SH pigs were scored with moderate and severe tail losses at the end of rearing. In terms of
performance, Pi pigs had significantly higher average daily gains than SH and BB pigs,
whether docked or undocked. Against previous expectations, no significant effect of the sire
breed or mean tail lesion score could be detected on the activity behaviour of the focus pens.
In conclusion, the present dissertation could confirm that both, the housing system and the
sire breed, have an effect on the behaviour and performance of growing and finishing pigs.
The amount and duration of aggressive behaviour and thus the incidences of skin lesions
could be decreased by reducing regrouping events at weaning through group housing during
the suckling period and/or through litterwise rearing in the farrowing system, all without
affecting the piglets’ expected performance. This decrease in weaning stress lowered the
incidence of tail lesions and tail losses of undocked pigs significantly. Significantly fewer BB
pigs had severe skin lesions compared to SH or Pi pigs. Also, significantly more BB pigs were
scored without tail lesions and tail losses for the first four weeks of the rearing period.
However, piglets from the two traditional sire breeds could not compete with docked and
undocked Piétrain pigs in terms of performance which possibly might be compensated by an
adjustment of the feeding regime. | de |