Outi Hälli

Seasonal alterations in circadian melatonin rhythms of the European wild boar and domestic gilt.

The aims of the present study were: 1) to determine if the European wild boar exhibits a circadian pattern of melatonin secretion under its natural light environment; 2) to compare this pattern with the pattern in domestic pigs reared under the light environment typical for domesticity; and 3) to determine if there are seasonal alterations in melatonin rhythms. Four to six young, pure‐bred, European wild boars and four to six cross‐bred (Yorkshire×Finnish Landrace) domestic gilts were sampled at 2‐hr intervals for 48 hr at the spring/autumn equinoxes and summer/winter solstices. Samples were obtained via saphenous arterial catheters from the wild boars and via ear vein catheters from the domestic gilts. The ambient light intensity was recorded simultaneously with sampling both outdoors and indoors. Following ether extraction, the serum samples were assayed for melatonin using a commercial RIA (Bühlman®). All the experimental animals exhibited a distinct circadian pattern in melatonin secretion, with high concentrations occurring during the scotophase. There was no difference in scotophase melatonin response between the wild boars and domestic gilts in any season in terms of mean melatonin concentration or peak value. The mean duration of increased melatonin secretion (more than two standard deviations over a mean photophase concentration) in 24 hr in the wild boars in spring, summer, autumn and winter, was 10, 6, 11 and 17 hr, respectively, and in the domestic gilts, 9, 8, 12 and 11 hr, respectively. These results demonstrate the existence of circadian rhythm in melatonin secretion in both the European wild boar and domestic pig. In both groups, the duration of secretion is subject to seasonal alterations. The results suggest no difference in photoperiodic‐melatonin transduction between the European wild boar and domestic pig whether due to altered genotype or reduced light environment.

Prevalence of and risk factors associated with viral and bacterial pathogens in farmed European wild boar

Abstract The aim of this study was to estimate in farmed European wild boars the prevalence of and risk factors associated with a range of common porcine viral and bacterial infections, namely, porcine parvovirus (PPV), porcine circovirus type 2 (PCV2), swine influenza virus (SIV), Aujeszky’s disease virus (ADV), classical swine fever virus (CSFV), swine vesicular disease virus (SVDV), coronavirus causing transmissible gastroenteritis (TGEV), porcine reproductive and respiratory syndrome virus (PRRSV), Mycoplasma hyopneumoniae, Lawsonia intracellularis, Brucella spp., and Leptospira spp. A sampling frame was compiled based on a national record of wild boar farmers, and 32 farms were surveyed. Serological screening was carried out on 303 samples from animals slaughtered between 2005 and 2008, and random-effect logistic regression models were developed for pathogens with a ‘non-zero’ prevalence. The apparent animal prevalence for PPV, PCV2, and L. intracellularis was 46.5% (95% confidence interval [CI] 41–52%), 51.1% (95% CI 45–57%) and 59.2% (95% CI 54–65%), respectively. Apparent farm seroprevalence rates for PPV, PCV2 and Lawsonia intracellularis were 56.3% (95% CI, 39–73%), 21.9% (95% CI, 8–36%) and 78.1% (95% CI, 64–92%), respectively. No antibodies were detected against SIV, ADV, CSFV, SVDV, TGEV, PRSSV, Leptospira spp., Brucella spp., or M. hyopneumoniae. Increasing herd size, proximity to dense populations of domestic swine and later sampling times within the survey period were found to be risk factors. Overall, the seroprevalence of these pathogens in farmed wild boar was similar to that in the farmed domestic pig population in Finland. However, it is possible that the rearing of wild boars in fenced estates may predispose them to particular infections, as reflected in higher antibody titres.

Farmed wild boars exposed to Toxoplasma gondii and Trichinella spp.

The meat of wild boar (Sus scrofa L.) can be a source of human infections with zoonotic parasites Toxoplasma gondii and Trichinella spp. We screened 197 wild boar sera collected at slaughter from 25 Finnish farms in 2007-2008 for serological evidence of infections with these parasites. Using a commercial direct agglutination test at a serum dilution of 1:40, T. gondii-specific IgG antibodies were detected in 65 (33.0%) samples, on 14 (56.0%) farms. Females, animals older than 24 months, animals of small herds, and animals originating from south-western parts of Finland were more often T. gondii-seropositive than were males, younger animals, animals of larger herds, and animals originating from the north and east, respectively. Four (2.0%) of the sera, originating from three (12.0%) farms, tested Trichinella-seropositive with an in-house ELISA and a conservative cut-off for seropositivity. One farm had both T. gondii- and Trichinella-seropositive animals. Taken together, an infection source had been present on 16 (64.0%) farms, and 69 (35.0%) of the 197 farmed wild boars intended for human consumption had specific serological evidence of exposure to a zoonotic parasite.

Housing During Early Pregnancy Affects Fertility and Behaviour of Sows

From 1.1.2013 EU legislation will permit stall-housing of dry sows for only 4 weeks post-service. Stalls are associated with compromised animal welfare, but group housing comes with risks from social confrontations. Studies on housing effects on fertility have produced contradictory results as systems are inconsistently defined. Effects of housing on pregnancy rate 28 days post-service (P28), early disruption of pregnancy (EDP) and behaviour were investigated in 12 replicates of 40 sows. Half of the animals were stalled (treatment S, mean parity 2.4) and half group-housed adjacent on 5.1 m(2) deep litter per sow (treatment G, mean parity 2.3). Pregnancy was detected using real-time ultrasound. An EDP-diagnosis required a drop of salivary progesterone concentration from >15.9 to <15.9 mmol/l in a series of samples taken on days 17, 20, 24 and 27 post-service. Behaviour was scan sampled on day 27 for 120 min with 10-min intervals. Data was analysed using mixed regression models in MLwiN. Treatment S increased the odds for P28 with 2.3 and the pregnancy rate of a treatment group with 0.1 compared with G. G increased the odds for EDP with 4.6. Treatment did not affect total exploratory or total passive behaviour. S sows explored floor and fixtures (not bedding) more and performed more passive sitting than G sows. Social stress may have caused the impaired reproductive performance in G sows. S sows showed behavioural signs of decreased welfare, but no corresponding reproductive effects. An interdisciplinary approach is needed when evaluating the appropriateness of housing systems.

Environmental enrichment in early life affects cortisol patterns in growing pigs.

Effects of environmental enrichment at different stages of life on stress physiology of pigs were investigated in a trial with 63 groups, each of four siblings. In each of the three growing phases (suckling 0 to 4 weeks of age, nursery 5 to 9 weeks, fattening 10 to 24 weeks) pens either were (=E) or were not (=0) enriched. Accordingly, the treatments were (i) 000, (ii) E00, (iii) EE0, (iv) 00E, (v) 0EE and (vi) EEE. The enrichment material, renewed twice daily to leave a thin layer, consisted of wood shavings and chopped straw. Salivary cortisol was sampled hourly from 0700 to 1900 h at the age of 9 and 21 weeks. The presence of a circadian secretion rhythm was evaluated by an intra-assay coefficient of variation-based method. An adrenocorticotropic hormone test was performed at 21 weeks. Treatment effects on the odds of a physiological cortisol rhythm were assessed by logistic regression, and effects on cortisol concentrations with a repeated measures GLM. Substrate-enrichment from 0 to 9 weeks of age increased the odds of a rhythm as compared to barren housing (odds ratio (OR) = 30.0, P < 0.01). A flat cortisol secretion pattern may indicate chronic stress and/or delayed maturation of the rhythm. Barren as compared to enriched rearing (0 to 4 weeks of age) seemed to cause a blunted secretion rhythm at 21 weeks of age. Although behavioural and tail lesion observations provided support to the assumption that a blunted rhythm indicates chronic stress, the biological significance of these cortisol results needs confirmation in future studies.

Fertility of Sows Fed ad libitum with a High Fibre Diet During Pregnancy

The effect of ad libitum (ADLIB) feeding strategy on the fertility of the group housed sow was studied in a prospective field trial during 1.5 years. All study animals farrowed under standard farrowing circumstances in crates, and they were provided with an ad libitum feeding throughout the 30-day lactation. After weaning, animals were randomly allocated to one of the two dry sow feeding strategies (AD LIB or CONT). After oestrus detection in groups, they were artificially inseminated and moved into pregnancy pens with partially slatted floor, in groups of 40 sows each. The ADLIB sows (n = 447) were loose housed and provided with ad libitum access to 7.7 MJ/kg feed high in fibre from two feeders per group. The control sows (n = 479; CONT) were also loose housed and given a standard dry sow feed in feeding stalls once a day (2.5 kg/day. The energy content of the feed was 9.3 MJ/kg NE). The feeding strategy (ADLIB vs CONT) had no effect on pregnancy rate (85.8 vs 90.9, p > 0.05), weaning to oestrus interval (7.7 vs 7.3 days, p > 0.05), piglets born alive (11.5 ± 3.5 vs 11.6 ± 3.3, p > 0.05), stillborn piglets (1.2 ± 1.8 vs 0.9 ± 1.5, p > 0.05) nor on progesterone concentration (p > 0.05). CONT sows weaned more piglets (9.7 ± 2.2 vs 9.4 ± 2.0, p < 0.01), whereas the piglets of AD LIB sows were heavier at weaning (8.8 ± 0.9 vs 8.0 ± 1.3 kg, p < 0.05). In conclusion, ad libitum feeding with a high in fibre diet during pregnancy did not affect the reproductive performance.

A practical method for non-surgically inserting intra-arterial catheters in European wild boars (Sus scrofa).

In endocrinological studies, the usual methods for taking blood samples are impractical because of the need for frequent sampling, and catheterization is required. The catheterization methods described for domestic pigs are not suitable for use with European wild boars (Sus scrofa) under field conditions. We describe a method for inserting an intra-arterial catheter into the European wild boar. The animals were sedated with a combination of medetomidin (Domitor 1 mg/ml, Orion-Farmos, Finland) and zolazepam and tiletamine (Zoletil forte vet 50 mg/ml + 50 mg/ml, Virbac Laboratories, France). Four animals were catheterized and sampled at 2-h intervals for 48 h in March under winter conditions and five in June under summer conditions. In March, all the catheters remained in place for the entire sampling period. In June, one animal managed to displace the catheter from its artery, but it was recatheterized and the rest of the samples were collected without problems. This catheterization method is relatively easy to carry out and requires no special facilities.

Short or long day light regimes may not affect reproductive performance in the sow.

The objective of this study was to evaluate the effect of short or long day light regimes on the reproductive performance in the sow. The study comprised approximately 1300 sows and their 3400 breedings in three commercial sow pools, in which a batch farrowing of 40 sows was employed. Each batch remained in the farrowing unit for 8 weeks under either a short day (10 h light, 14 h dark) or a long day (14 h light, 10 h dark) light regime. After weaning and transportation to the central unit, all sows were kept under the long day regime until they were moved back to the farrowing unit. Production results for each individual sow were recorded. The effect of the two different light regimes on the farrowing rate (FR) and on the weaning-to-oestrous interval was evaluated using logistic and Poisson regression models, respectively. The light regime affected none of the parameters significantly. The FR in June, July and August did, however, drop below that in December, January and February (OR 0.7, p < 0.05). The FR was affected by the sow pool (p < 0.01). Parity two sows exhibited a lower FR (OR 0.5, p = 0.05) and higher incidence of delayed first oestrus (IRR 2.7, p < 0.01) than did older sows. This study indicates that despite an artificial light regime, sows may still react to changes in season. In conclusion, use of simple light regime to obtain complete control over reproductive performance appears to be difficult.

Feeding affects reproductive performance and reproductive endocrinology in the gilt and sow

The pig is considered to be a highly prolific species with ahigh ovulation rate and if mated at the right moment, thesow also holds a very high probability of pregnancy. It isgenerally accepted that little variation in live weight of thesow throughout the production cycle is associated withhigh fertility and improved longevity. This goal requireshigh energy intake during lactation, which may beachieved by ad libitum feeding with high energy high pro-tein lactation diet without feed restriction, especially dur-ing the last part of lactation. In endocrinological terms,gonadotrophin secretion is affected by suckling and met-abolic messengers, which transfer information regardinglactation and metabolic state of the dam. These messagesare received by the hypothalamo-pituitary axis and even-tually follicular development is either inhibited orencouraged, depending on the messages. Managementpractices such as intermittent suckling are developed toalleviate the sow to meet with the metabolic challengesimposed by lactation and expected fertility. After mating,social stress and restricted feeding may create a situationwhere embryonic survival and pregnancy is jeopardized.The risk of losing embryos/pregnancy may be highestwhen individual sows experience considerable food dep-rivation for longer than two days around implantation.Feeding a sow group more may provide the farmer withsimple solution to problems with early pregnancy.Approaching term, compromising between high birthweigh of newborn piglets associated with abundant feed-ing and a feed restriction together with increase in fiber toimprove intestinal function may be the strategy of choice.

Metastrongylus spp. infection in a farmed wild boar (Sus scrofa) in Finland

Summary Metastrongylus spp. (Nematoda, Metastrongylidae) are lung worms of swine and occur worldwide. Species in the family include M. apri, M. pudendotectus, M. asymmetricus, and M. salmi. Earth worms are intermediate hosts and pigs get infected when eating earth worms. In Finland wild boar farming began in the 1980s and now there are over hundred farms and over 2000 wild boars in different parts of the country. This case report is part of a study aiming to get more information about the diseases that occur in the farmed wild boar population in Finland. Lungworms were detected in an eight month old farmed wild boar sent for necropsy from a farm situated in eastern Finland. In the group of 25 animals of about the same age, the farmer had noticed poor growth and gait abnormalities. He submitted two euthanized boars (A and B) for necropsy. A routine necropsy was performed and tissue samples were collected for histopathology, bacteriology and parasitology. The boar A was in a poor nutritional condition. The lungs were slightly mottled, but otherwise normally inflated. Large numbers of white thread like nematodes were detected in the bronchi (Fig. 1.). Bones were soft. In the faecal sample, 7500 EPG Metastrongylus spp. eggs were detected with flotation (Fig. 2.). The boar B was in a moderate nutritional condition. No lung worms were detected. The main pathological diagnosis of both was osteomalacia due to deficiency of mineral feeding. However, the the poor nutritional condition of the boar A infected with lung worms was possibly partly due to the lung worm infection. Four additional faecal samples were sent from remaining boars from the farm and two