Housing, stress and productivity : studies in growing and reproducing pigs

Commercial pig production presents the animals with a multitude of potentially stressful challenges. Distress is a threat to animal welfare and may impair productivity. This research aimed to investigate productivity of pigs in relation to some common practices of pig production known to be stressful, to estimate the amount of stress or the level of welfare of the animals, and to establish relationships between stress or animal welfare measures and productivity. To address these issues, four studies were carried out. Studies I and II investigated effects of moderate enrichment on behaviour, basal cortisol secretion, health and daily gain in growing pigs (0-21 weeks of age). Effects of both current and early environmental enrichment were investigated. Small groups with siblings were accommodated in pens either barren or enriched with a moderate amount of chopped straw and wood shavings. Six enrichment regimes were used involving a stable environment or changes in enrichment status at 5 and/or 9 weeks of age. Enriched as compared to barren housing increased average daily gain and decreased post-weaning diarrhoea in the nursery. Current housing, as well as the early environment (0-4 or 0-9 weeks of age), affected stress physiology as measured by behaviour and basal cortisol secretion. Barren housing or experience thereof caused signs suggestive of chronic stress. Stress indicators were not associated with productivity. These results support the use of enrichment for pigs in early life, especially if bedding is scarce later in life. Study III compared the fertility of sows housed either individually or in groups on deep litter from weaning to four weeks of pregnancy. Stall housing decreased the odds for early disruption of pregnancy and increased the odds for pregnancy at day 28 post-service. The causes remained undisclosed, but social stress during short periods of time around oestrus and early pregnancy was proposed. Behavioural indicators showed clear signs of stress in stalls, but behaviour was not associated with fertility. The level or type of stress in stalls may have been insufficient to affect reproduction. These results emphasize the need for a better understanding of factors impairing fertility in sow groups. In Study IV the welfare status of pigs on commercial farms was assessed using an environment-based index comprising several subscales. Welfare scores were regressed on fertility measures. Good-quality floors and stockmanship were the most influential predictors of good fertility, providing some evidence of an association between higher levels of animal welfare (i.e. low levels of distress) and good reproductive performance.Nykyaikaiseen eläintuotantoon liittyy lukuisia tekijöitä, jotka saattavat olla eläimille stressaavia. Stressi uhkaa eläinten hyvinvointia ja heikentää myös niiden tuotosta. Tutkimuskokonaisuuden tavoitteina oli selvittää tiettyjen ympäristötekijöiden vaikutuksia sikojen tuotokseen, arvioida sikojen kokeman stressin määrää tai hyvinvoinnin tasoa sekä tutkia stressin tai hyvinvoinnin tason roolia havaittujen tuotosvaikutusten välittäjinä. Kuivikkeen puutteen tiedetään stressaavan sikoja. Osaritiläkarsinoihin ja lietelannanpoistoon sopivan, niukan kutteri silputtu olki kuivituksen tehoa stressin vähentäjänä tukittiin eri kasvatusvaiheissa annettuna. Kuivitus paransi kasvua välikasvattamossa ja vähensi vieroitusripulia. Kuivikkeen käyttäminen vähensi stressin oireita kuten hännänpurentaa. Varhainen ympäristö vaikutti myöhempään stressifysiologiaan. Kuivittaminen porsituskarsinassa vähensi häiriökäyttäytymistä lihasikalassa. Tulosten perusteella voidaan suositella porsituskarsinoiden kuivittamista myöhemmän häiriköinnin vähentämiseksi. Kuivitetuista karuihin karsinoihin siirtäminen saattaa toisaalta lisätä hännänpurentaa. Varhaistiineyden pito-olosuhteidan vaikutuksia emakoiden hedelmällisyyteen tutkittiin vieroittamalla joko joutilashäkkeihin tai 20 emakon väljiin, runsaasti olkikuivitettuihin ryhmiin ruokintahäkeillä. Tiineyden mahdollisuus 28. päivänä siemennyksestä oli häkeissä 2,3 kertaa suurempi kuin ryhmissä, ja alkaneen tiineyden keskeytymisen riski ryhmissä 4,6 kertaa suurempi kuin häkeissä. Tulokset viittaavat voimakkaan stressin ja/ tai huomattavien energiansaantierojen lyhytaikaiseen esiintymiseen ryhmissä kiiman ja/ tai alkutiineyden aikana. Stressin mittaamiseksi tehdyt käyttäytymishavainnot kokeen loppuvaiheessa osoittivat häkkiemakoiden olevan selvästi stressaantuneita, mutta oireilla ja hedelmällisyydellä ei ollut yhteyksiä. Emakoiden hyvinvoinnin yhteyksiä hedelmällisyyteen tutkittiin toimivilla tiloilla. Hyvinvointia mitattiin olosuhteita painottavalla indeksillä. Emakoiden rotu huomioiden kokonaispistemäärä ei assosioitunut hedelmällisyyteen. Hyvänlaatuiset lattiat ja korkea eläinten hoidon taso kuitenkin nopeuttivat tuotantokiertoa. Emakoiden hedelmällisyyttä koskeneet tutkimukset osoittivat alkutiineyden ryhmäkasvatukseen liittyvän riskejä sekä tuottavuuden että hyvinvoinnin osalta. Toimiva tiloja tarkasteltaessa erot kasvatusmuotojen välillä olivat kuitenkin pienet, todennäköisesti pitkäjänteisen tuotannon kehittämisen seurauksena. Häkeissä pitoon liittyneet stressin oireet kertovat heikentyneestä hyvinvoinnista ja muistuttavat osaltaan tarpeesta löytää toimivia ratkaisuja alkutiineiden emakoiden ryhmäkasvatukseen

Novel saliva biomarkers for stress and infection in pigs : Changes in oxytocin and procalcitonin in pigs with tail-biting lesions

There is a need for feasible and reliable measures to improve and evaluate production animal health and welfare. Oxytocin is a promising novel stress-related biomarker and procalcitonin may be a measure of sepsis. Both have potential for use in pigs and can be measured from saliva, which allows on-farm sampling with minimal impact on the animals. The current study sought to further validate these measures using a spontaneous situation that causes both stress and an increased risk for infections in pigs, namely a tail-biting outbreak. Grower pigs on a commercial farm belonging to three different phenotype groups were selected: control pigs from control pens (CC, N = 30), control pigs (CTB, N = 10), and pigs with tail lesions from pens with a tail-biting outbreak (LTB, N = 27). A single sample of saliva was collected from each pig and analysed for a range of biomarkers related to stress, infection, inflammation, and immune activation. Oxytocin tended to be higher in CC pigs than in LTB pigs, while cortisol was higher in CTB than CC pigs. Procalcitonin tended to be higher, and haptoglobin was higher in LTB than in CC pigs. Adenosine-deaminase levels were similar between phenotypes. These results provide further evidence for the link between stress and tail biting, and indicate that tail-biting lesions are potential routes for systemic spread of bacteria. Further research into saliva oxytocin as a stress biomarker and saliva procalcitonin as a sepsis biomarker in pigs is warranted.Peer reviewe

Managing undocked pigs : on-farm prevention of tail biting and attitudes towards tail biting and docking

Abstract Background Tail biting is a common and serious welfare problem in pig production, causing large economical losses. Tail docking is performed routinely in most EU countries to reduce the tail biting risk. However, tail docking is painful, and does not prevent tail biting totally. The risk factors behind tail docking are multifactorial and most analyses are based on studies using biological or epidemiological approaches. There is very little information available on how producers deal with tail biting on-farm. There are also no studies on the attitude of producers towards tail docking and tail biting in systems with long-tailed pigs. We aimed to study how farmers rate the efficiency of different measures for preventing and intervening with tail biting, when tail docking is not allowed. Furthermore, we investigated the attitudes of Finnish farmers to tail docking and tail biting. Results Respondents scored feeding-related issues to be most important for prevention of tail biting, identifying and removing the biting pig as most important intervention measures, and straw as the most important manipulable material when preventing tail biting. Tail biting was not perceived as a very serious problem by over 70 % of the respondents, even though docking is not allowed, and was reported to occur close to a level which was also considered acceptable by the respondents. Most respondents did not think it is probable they would raise tail docked pigs if it were possible, but about 21 % probably would. Conclusions In comparison with other authors’ findings, the ranking of importance of risk factors for tail biting differs between scientists and farmers, and between farmers in different cultures of pig production. In addition, the attitude towards tail biting and tail docking appears to be very different in producers with different experiences of tail docking. These results indicate that a scientist-farmer dialogue, as well as international communication is important when trying to reduce the risk of tail biting, and subsequently the need for tail docking

Sick and grumpy: changes in social behaviour after a controlled immune stimulation in group-housed gilts

Poor health is associated with an increased risk of tail biting outbreaks in pigs. We propose that this is because illness changes social dynamics either by changing the behaviour of the sick pig towards its penmates, the behaviour of the healthy penmates towards the sick pig, or both. We tested the effect of immune stimulation (lipopolysaccharide (LPS) injection: O111:B4; 1.5 mu g kg(-1) IV) on social behaviour in gilts housed in triplets in a cross-over experiment. Each pen was subjected to the control treatment (all three pigs injected with saline) and then LPS treatment (one pig injected with LPS, two injected with saline), or vice versa. LPS injected pigs had a shift in social motivation and performed more tail- and ear- directed behaviour than saline pigs two days after injection. They seemed to fit the description of 'sick and grumpy'. This change was seen about 40 h after the signs of acute illness dissipated and was not accompanied by a similar increase in activity. We discuss possible mechanisms for this behavioural change in light of changes in neurotransmitter levels at three days after LPS injection described in a previous experiment.Peer reviewe

Hännänpurentaan liittyvät sikojen väliset yksilölliset erot

Hännänpurenta on sikojen häiriökäyttäytymisen muoto, jonka tarkkaa alkuperää ei tunneta.Hännänpurennalle on kuitenkin löydetty laajoissa kartoituksissa lukuisia ympäristöperäisiäriskitekijöitä, jotka eivät kuitenkaan kaikilla yksilöillä johda hännänpurentakäyttäytymiseen.Yhteistä riskitekijöille on niiden aiheuttama stressi eläimelle. Sikayksilöt saattavat reagoidastressoreiden läsnäoloon yksilöllisesti, mikä selittäisi ilmiön, missä samassa ympäristössä yksisika puree ja toinen ei.Stressikäyttäytymistä voidaan tutkia vertaamalla stressiin liittyvien käyttäytymismuotojenesiintymistä ja aivoissa tapahtuvia neurobiologisia muutoksia ajallisesti ja määrällisesti.Serotoniini ja dopamiini ovat hermovälittäjäaineita, joilla on yhteys muun muassakäyttäytymiseen ja häiriökäyttäytymiseen. Kroonisen stressin tiedetään muuttavan aivojenrakennetta ja toimintaa.Tässä tutkimuksessa etsitään neurobiologisia ja fysiologisia eroja poikkeavasti janormaalisti käyttäytyvien sikayksilöiden välillä hännänpurennan aikana. Tutkittavat lihasiatjaettiin kolmeen ryhmään (PURIJA, UHRI, KONTROLLI) käyttäytymistarkkailun avulla saadunkeskimääräisen purentafrekvenssin mukaan. Ryhmiä verrataan anatomisten aivoalueiden(striatum, limbinen alue, etuaivokuori, hippokampus, talamus, hypotalamus) hermovälittäjäaineidenpitoisuuden ja niiden verenkierrossa olevien esiasteiden suhteen. Muita hännänpurentaan jastressiin liittyviä fysiologisia mekanismeja kartoitetaan määrittämällä kortisolin erityksenvuorokausirytmi syljestä, jejunumin alueen morfologinen suoliston kunto ja muu patologinen taihematologinen eroavuus ryhmien välillä. Tämä paperi keskittyy tutkimusten taustan jamenetelmien esittelyyn sekä koeryhmien identifiointiin. Fysiologisten näytteiden analysointi onyhä kesken.Tutkimus kuuluu yhteispohjoismaiseen NKJ- hankkeeseen “Tail biting and tail docking inthe pig: biological mechanisms, prevention, treatment and economic aspects”. Hankkeessaetsitään hännänpurentaan johtavia yksilöllisiä, ympäristö- ja rehuperäisiä riskitekijöitä, purentaaennaltaehkäiseviä ja purentaepidemian pysäyttäviä keinoja, toimivia hoidon- ja kivunlievityksenmuotoja ja mallitetaan hännänpurennan aiheuttamia taloudellisia kustannuksia

Sow mortality is associated with meat inspection findings

Sow meat inspection (MI) and mortality data are important sources of information for use in herd health work. This observational study examined whether MI results of sows associate with sow mortality in Finnish sow herds. We also described some MI findings of sows to create basic references in order to encourage their use in herd health work. The project was widely advertised to farmers of sow herds and practicing veterinarians. Ten herds joined the project voluntarily and 36 other herds after they were contacted by the researchers. MI data (carcass weight, lean meat percentage, arthritis, abscesses, liver condemnations, milk spots, organ condemnations, pleuritis, pneumonia, shoulder ulcers, tail biting, whole carcass condemnations, partial carcass condemnations and kg of meat condemned) were made available by the three largest slaughterhouses in Finland, and sow mortality data were obtained from the National Swine Herd Register for 39 of the study herds for the year 2014. The mean herd size of participating herds was 529 females with a standard deviation of 479 and mean annual mortality 9.0% +/- 5.2%. As much as 22.8% of the 7437 slaughtered sows had at least one MI finding. Heavy carcasses were less likely to have at least one MI finding. A median (range) of 1.8% (0-7.2) and 11.8% (0-34.6) of the sows were recorded to have a whole and partial carcass condemnation, respectively. The most common MI findings were abscesses (5.7%, 0-16.3), shoulder ulcers (3.6%, 0-22.9) and arthritis (2.1%, 0-13.3). In individual carcasses, abscesses were associated with arthritis, shoulder ulcers and pneumonia, which was indicative that these animals most likely had a systemic infection. Pneumonia findings were associated with pleuritis. At the herd level, the increase of sow mortality by 1% was associated with an increased percentage of slaughtered females with at least one MI finding 0.8% (P = 0.01). If sow mortality increased by 1%, the odds ratio for the herd having more than a median percentage of pleuritis was 1.3 (95% confidence interval; 1.01 - 1.57, P = 0.04) compared to the situation of the herd having less than a median percentage of pleuritis. Also, if sow mortality increased by 1%, the percentage of partial carcass condemnations of females increased by 0.4% (P = 0.08). These results suggest that high mortality was associated with an increase of some MI findings. MI results of sows should be used in herd health follow-up of sow health.Peer reviewe

Physiological indicators of stress and meat and carcass characteristics in tail bitten slaughter pigs

Peer reviewe