Friend or foam? Improved methods for stunning of pigs with foam : effects of repetition and scent on pig reaction to foam
There are several methods available for stunning of pigs before slaughter, but the most frequently used at larger abattoirs are electricity and CO2. There are advantages and disadvantages with both methods. As there is no method that does not have major animal welfare drawbacks. EFSA (European Fo...
| Autor principal: | |
|---|---|
| Formato: | H3 |
| Lenguaje: | Inglés sueco |
| Publicado: |
SLU/Dept. of Animal Environment and Health (until 231231)
2022
|
| Materias: |
| _version_ | 1855572929915387904 |
|---|---|
| author | Blad, Miranda |
| author_browse | Blad, Miranda |
| author_facet | Blad, Miranda |
| author_sort | Blad, Miranda |
| collection | Epsilon Archive for Student Projects |
| description | There are several methods available for stunning of pigs before slaughter, but the most frequently
used at larger abattoirs are electricity and CO2. There are advantages and disadvantages with both
methods. As there is no method that does not have major animal welfare drawbacks. EFSA
(European Food Safety Authority) concluded in 2004 that research on new and developed methods
for stunning of pigs before slaughter needs to be prioritised. However, research in the area is lacking.
One method that has been researched is stunning with nitrogen filled high expansion foam. With
this method it is possible to use a gas (e.g., nitrogen) that is not thought to be as aversive to pigs as
carbon dioxide, but that is difficult to use in free form due to having similar density as air. The foam
keeps the gas from mixing with air and purges the space from air helping to create an anoxic
environment in a shorter time. When this method has been studied, questions have arisen on how
aversive the foam itself is to the pigs, and whether or not it is possible to reduce this aversiveness
by, for example, adding a scent to the foam or by exposing the pigs to foam on repeated occasions.
The aims of this study were to investigate if the pigs’ behaviour were altered when scent was added
to the foam, and also if repeated exposure to foam would affect the pigs’ behaviour.
In total, 50 pigs with an age of 14-16 weeks were included in this study. There were 30 pigs in the
group with a vanilla scent added to the air-filled foam, and 20 pigs in the group that was exposed to
air-filled foam without an added scent on three consecutive days. The observations from the first
exposure to foam in the group with 20 pigs in the repeated study were also used as a control group
to the study with an added scent.
The result from the experiment with foam with an added scent showed that there was a larger
proportion of pigs exploring the foam when it had an added vanilla scent. There was also an
increased interest in that group to explore the wall, as well as increased activity. No effects could be
shown on number of escape attempts.
The result from the experiment where pigs were exposed to foam on three consecutive days showed
a larger proportion of pigs vocalising, both in forms of grunts and screams/squeals, on day three
than on day one. There were also more escape attempts on day three than on day one. Furthermore,
increased exploration of the walls and decreased exploration of the floor was seen from day one to
three.
In conclusion the results of this study indicate that it is possible to increase the pigs’ interest in the
foam by adding a scent to the foam. If foam is to be given an added scent in the future more research
is needed, both in terms of relevant scent and concentration as well as assuring it has no effect on
the meat for the consumer. The results also indicate that the foam is not highly aversive to pigs, as
pig avoidance behaviour towards the foam does not greatly increase when exposed to it repeatedly.
Number of escape attempts increased slightly however, and a future study with a larger number of
pigs might reveal more information. The increased vocalisation could either indicate a return to
more normal levels of vocalisations because of adaption to the environment but could also mean an
increased reactivity to the situation. It is also possible that increased vocalisation comes from
knowing that that they will soon be let out and therefore try to communicate with their box mates.
Further studies would be needed to confirm stress levels in the pigs in these situations. |
| format | H3 |
| id | RepoSLU17646 |
| institution | Swedish University of Agricultural Sciences |
| language | Inglés swe |
| publishDate | 2022 |
| publishDateSort | 2022 |
| publisher | SLU/Dept. of Animal Environment and Health (until 231231) |
| publisherStr | SLU/Dept. of Animal Environment and Health (until 231231) |
| record_format | eprints |
| spelling | RepoSLU176462022-04-02T01:01:28Z Friend or foam? Improved methods for stunning of pigs with foam : effects of repetition and scent on pig reaction to foam Hur skumt kan det vara? Förbättrade metoder för bedövning av gris med skum : effekter av upprepning och lukt på grisars reaktioner till skum Blad, Miranda pig behaviour stunning foam smell scent fear assessment animal welfare There are several methods available for stunning of pigs before slaughter, but the most frequently used at larger abattoirs are electricity and CO2. There are advantages and disadvantages with both methods. As there is no method that does not have major animal welfare drawbacks. EFSA (European Food Safety Authority) concluded in 2004 that research on new and developed methods for stunning of pigs before slaughter needs to be prioritised. However, research in the area is lacking. One method that has been researched is stunning with nitrogen filled high expansion foam. With this method it is possible to use a gas (e.g., nitrogen) that is not thought to be as aversive to pigs as carbon dioxide, but that is difficult to use in free form due to having similar density as air. The foam keeps the gas from mixing with air and purges the space from air helping to create an anoxic environment in a shorter time. When this method has been studied, questions have arisen on how aversive the foam itself is to the pigs, and whether or not it is possible to reduce this aversiveness by, for example, adding a scent to the foam or by exposing the pigs to foam on repeated occasions. The aims of this study were to investigate if the pigs’ behaviour were altered when scent was added to the foam, and also if repeated exposure to foam would affect the pigs’ behaviour. In total, 50 pigs with an age of 14-16 weeks were included in this study. There were 30 pigs in the group with a vanilla scent added to the air-filled foam, and 20 pigs in the group that was exposed to air-filled foam without an added scent on three consecutive days. The observations from the first exposure to foam in the group with 20 pigs in the repeated study were also used as a control group to the study with an added scent. The result from the experiment with foam with an added scent showed that there was a larger proportion of pigs exploring the foam when it had an added vanilla scent. There was also an increased interest in that group to explore the wall, as well as increased activity. No effects could be shown on number of escape attempts. The result from the experiment where pigs were exposed to foam on three consecutive days showed a larger proportion of pigs vocalising, both in forms of grunts and screams/squeals, on day three than on day one. There were also more escape attempts on day three than on day one. Furthermore, increased exploration of the walls and decreased exploration of the floor was seen from day one to three. In conclusion the results of this study indicate that it is possible to increase the pigs’ interest in the foam by adding a scent to the foam. If foam is to be given an added scent in the future more research is needed, both in terms of relevant scent and concentration as well as assuring it has no effect on the meat for the consumer. The results also indicate that the foam is not highly aversive to pigs, as pig avoidance behaviour towards the foam does not greatly increase when exposed to it repeatedly. Number of escape attempts increased slightly however, and a future study with a larger number of pigs might reveal more information. The increased vocalisation could either indicate a return to more normal levels of vocalisations because of adaption to the environment but could also mean an increased reactivity to the situation. It is also possible that increased vocalisation comes from knowing that that they will soon be let out and therefore try to communicate with their box mates. Further studies would be needed to confirm stress levels in the pigs in these situations. Det finns flera metoder för bedövning av gris vid slakt, där de vanligast använda på större slakterier är koldioxid (CO2) och elektricitet. Med båda metoderna finns både för- och nackdelar. Eftersom det inte finns någon bedövningsmetod som är helt fri från djurvälfärdsmässiga nackdelar menade EFSA (European Food Safety Authority) redan 2004 att forskning på nya och utvecklade bedövningsmetoder av gris inför slakt är önskvärt och bör prioriteras. Trots detta har väldigt få studier gjorts inom ämnet sedan dess. En metod som har studerats är bedövning via ett högexpansivt skum innehållande inerta gaser. En gas som studerats i denna kontext är kvävgas, vilken inte verkar ge upphov till lika kraftigt aversivt beteende hos grisar som koldioxid gör. Skummet gör så att gasen inte blandas med luft vilket annars sker då luft och kvävgas har liknande densitet. Skummet trycker även undan luften så att utrymmet snabbare bli syrefritt, vilket är nödvändigt då bedövning med inerta gaser sker genom syrebrist. I studier kring denna metod har frågetecken uppkommit kring hur obehagligt grisarna upplever skummet, och om det skulle gå att minska det obehaget genom tillsats av till exempel en lukt eller genom att grisarna utsätts för skum vid upprepade tillfällen. Målet med denna studie var att studera om grisarnas beteende ändras om de utsätts för ett luftfyllt skum som är luktsatt, och om deras beteende ändras om de utsätts för icke luktsatt, luftfyllt, skum vid upprepade tillfällen. Totalt ingick 50 grisar mellan 14 och 16 veckors ålder i studien. Dessa var fördelade som följer: 30 grisar utsattes för luftfyllt skum med tillsatt vaniljlukt vid ett tillfälle, och 20 grisar utsattes för ett luftfyllt skum utan tillsatt lukt under tre på varandra efterföljande dagar. Observationerna från det första tillfället med de 20 grisarna i den upprepade studien användes som kontrollgrupp för studien med luktsatt skum. Resultatet av studien med luktsatt skum visar att grisarna utforskade det luktsatta skummet mer och att även utforskandet av väggarna i boxen ökade i frekvens. Aktiviteten ökade också i denna grupp men ingen ökning av flyktförsök sågs. Resultatet av studien där grisar utsattes för skum vid upprepade tillfällen visade att grisarna vokaliserade mer, både genom grymtningar och skrik, och uppvisade fler flyktbeteenden på dag tre än på dag ett. Det var även ett ökat intresse av att utforska väggen, men minskat intresse av att utforska golv på dag tre jämfört med dag ett. Sammanfattningsvis indikerar resultaten i den här studien att det är möjligt att öka grisarnas intresse för skummet genom att tillsätta en lukt till det. Om skummet ska luktsättas i framtiden behövs mer forskning, både på vilka lukter och koncentrationer som vore relevanta samt för att säkerställa att det inte har några effekter på köttet för konsumenten. Resultaten tyder också på att skummet inte är väldigt aversivt eftersom undvikandet av skum inte ökar kraftigt när grisarna utsätts för skum vid upprepade tillfällen. Antalet flyktförsök ökade dock något, men då siffrorna var så låga skulle en studie med fler grisar krävas för att säkerställa relevansen. Att vokaliseringen ökade kan tyda på en normalisering vokaliseringsnivån till följd av tillvänjning av miljön men skulle också kunna tyda på en ökad reaktivitet till situationen. Det är också möjligt att den ökade vokaliseringen kommer till följd av att grisarna förstår att de snart blir utsläppta och därför försöker kommunicera mer med grisarna utanför lådan. Vidare studier skulle krävas för att undersöka stressnivåerna hos grisar i denna typ av situationer. SLU/Dept. of Animal Environment and Health (until 231231) 2022 H3 eng swe https://stud.epsilon.slu.se/17646/ |
| spellingShingle | pig behaviour stunning foam smell scent fear assessment animal welfare Blad, Miranda Friend or foam? Improved methods for stunning of pigs with foam : effects of repetition and scent on pig reaction to foam |
| title | Friend or foam? Improved methods for stunning of pigs with foam : effects of repetition and scent on pig reaction to
foam |
| title_full | Friend or foam? Improved methods for stunning of pigs with foam : effects of repetition and scent on pig reaction to
foam |
| title_fullStr | Friend or foam? Improved methods for stunning of pigs with foam : effects of repetition and scent on pig reaction to
foam |
| title_full_unstemmed | Friend or foam? Improved methods for stunning of pigs with foam : effects of repetition and scent on pig reaction to
foam |
| title_short | Friend or foam? Improved methods for stunning of pigs with foam : effects of repetition and scent on pig reaction to
foam |
| title_sort | friend or foam? improved methods for stunning of pigs with foam : effects of repetition and scent on pig reaction to
foam |
| topic | pig behaviour stunning foam smell scent fear assessment animal welfare |