Epsilon Archive for Student Projects

Abstract

Pigs are exposed to several different environmental stressors in the modern production
from weaning, mixing, crowding etc. Preslaughter stressors may result in meat
quality problems, such as the formation of pale, soft and exudative meat as well as
the formation of dark, firm and dry meat, which makes the meat to be unattractive.
In 2012, the Swedish Yorkshire (SY) was replaced with the Dutch Yorkshire of the
Z-line (ZY) for financial decisions as well as the ZY having a more efficient breeding
progress in the ZY line. The SY has been indirectly selected for social behaviours to
a larger extent compared to the ZY since the sows of the SY has been selected in
group housed systems while the sows of the ZY have been housed individually. The
aim of this pilot study is therefore to investigate if there are differences in stress related
behaviours and meat quality between the SY and the ZY and between pigs provided
with social training (access pen) early in life with pigs not allowed social training
(control pen). The stress levels and meat quality were measured on in total of 60
pigs. Aiming to assess stress, a Novel Arena test and a Startle test were performed in
the pig facility short before slaughter and a Novel Arena test was also performed at
the slaughter plant. The lactate level in the blood and the temperature and pH of the
carcass was measured at the slaughter plant. During the suckling period, half of the
litters were in the access pen and had the opportunity to walk between two pens while
the remaining stayed within their pen, control pen. The result showed that there were
no significant differences in stress levels or meat quality between the breeds but the
SY had a significant higher meat percentage (P=0.021) compared to the ZY, which
may indicate that the ZY have a higher fat storage. If both of the breeds were kept in
control pens during the suckling period, the ZY had a significant higher growth rate
(P=0.008) and lower age at slaughter (P=0.008) compared to the SY. The pigs in the
control pen performed significant more hesitation (P=0.01) and activity (P=0.038)
compared to the pigs in the access pen in the Novel Arena test in the slaughter plant,
which may indicate that the pigs in the control pen may have been more stressed.
There was no significant difference in the meat quality for the different treatments.
In conclusion, there is no significant difference in the stress levels and meat quality
between the breeds. It may be a difference in stress levels between the treatments,
where the pigs in the access pen and thus with extra social training were less stressed,
but no significant difference between treatments was found for meat quality.

Grisar utsätts för flera olika typer av stress i den moderna produktionen från avvänjning,
blandning, trängsel m.m. Stress innan slakt kan leda till köttkvalitetsproblem så
som till exempel förekomst av blekt, mjukt och vattnigt kött samt bildandet av mörkt,
fast och torrt kött som gör köttet oattraktivt. Den svenska yorkshire rasen (SY) ersattes
år 2012 med den nederländska yorkshire rasen av Z-linjen (ZY) på grund av ekonomiska
anledningar samt att ZY har en mer effektiv avelsframgång. SY har indirekt
avlats för socialt beteende i större utsträckning än ZY eftersom suggorna av SY har
selekterats i grupphussystem medan suggorna av ZY har hållits individuellt. Syftet
med denna pilotstudie är därför att undersöka om det finns skillnader i stressrelaterade
beteenden och köttkvalitet mellan SY och ZY samt mellan grisar som fått extra
social träning (åtkomstbox) tidig i livet och grisar som inte fått extra social träning
(kontrollbox). Stressnivån och köttkvaliteten mättes på totalt 60 grisar. Novel Arena
test och Startle test utfördes i grisanläggningen för att mäta stress såväl som Novel
Arena testet i slakteriet. Laktatnivån i blodet samt temperatur och pH i slaktkroppen
mättes också på slakteriet. Under di-perioden var hälften av kullarna i en åtkomstbox
och hade möjligheten att gå mellan två grisningsboxar medan de resterande stannade
i sin egen box, kontrollbox. Resultatet visade att det inte fanns några signifikanta
skillnader mellan stressnivåerna och köttkvaliteten mellan raserna, men SY hade en
signifikant högre köttprocent (P=0,021) än ZY, vilket kan indikera att ZY har en
högre fettlagring. Om båda raserna hölls i kontrollboxen under di-perioden så fick
ZY en signifikant högre tillväxthastighet (P=0,008) samt lägre ålder vid slakt
(P=0,008) jämfört med SY. Grisarna i kontrollboxen tvekade mer (P=0,01) och hade
en högre aktivitet (P=0,038) jämfört med grisarna i åtkomstboxen under Novel Arena
testet i slakteriet, vilket kan indikera att grisarna i kontrollboxen var mer stressade.
Det fanns ingen signifikant skillnad i köttkvaliteten mellan de olika behandlingarna.
Sammanfattningsvist så finns det ingen signifikant skillnad i stressnivåerna och köttkvaliteten
mellan raserna. Det kan vara en skillnad i stressnivåerna mellan behandlingarna,
där grisarna i åtkomstboxen och därmed med extra social träning var mindre
stressade, men ingen signifikant skillnad mellan behandlingarna visades för köttkvaliteten.