J. V. Virolainen

Lameness and fertility of sows and gilts in randomly selected loose-housed herds in Finland.

The prevalence of lameness among 646 sows and gilts in 21 selected herds was determined; 8·8 per cent of the animals were lame and the most common clinical diagnoses were osteochondrosis, infected skin lesions and claw lesions. The lame animals had higher serum concentrations of haptoglobin and C-reactive protein than the sound animals. Animals housed on slatted floors had twice the odds of being lame and 3·7 times the odds of being severely lame than animals housed on solid floors. Yorkshire pigs had 2·7 times the odds of being lame than Landrace or crossbred animals. Higher parity and the use of roughage decreased the odds of the sows not becoming pregnant; however, lameness was not a risk factor for non-pregnancy.

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.

Investigation of a simplified artificial lighting programme to improve the fertility of sows in commercial piggeries

Two artificial lighting regimens were studied in a commercial unit of 800 sows. The aim was to develop a simplified lighting regimen to overdrive the effects of season on reproduction. A long-day group had a constant 16 hours light and eight hours dark photoperiod in all units during a production cycle. A short-day group had eight hours of light and 16 hours darkness in a farrowing unit for four weeks and in a mating unit for four weeks. After one month of pregnancy the short-day group was transferred to 16 hours light and eight hours dark for the rest of the dry-sow period. Production data were collected for eight months, and the farrowing rate, weaning to oestrus interval, culling rate for fertility problems and the number of live-born piglets were analysed. Seasonal infertility, which had previously affected the herd, was not detected in either group during the follow-up period. The farrowing rate was 90 per cent for both groups. The median weaning to oestrus interval was five days in both lighting regimens with ranges from four to 74 days in the short-day group and three to 55 days in the long-day group. The long-day programme had a positive effect on the weaning to oestrus interval. When the sows were classified as either ‘normal’, with a weaning to oestrus interval of up to 10 days, or ‘problem’ animals, with a weaning to oestrus interval of over 10 days, the short-day programme also had a positive effect. The culling rate for fertility problems was 2·4 per cent for the short-day group and 3·2 per cent for the long-day group (P=0·027). The only significant predictor for the number of live-born piglets was parity (P=0·027).

Regional Eradication of Mycoplasma hyopneumoniae From Pig Herds and Documentation of Freedom of the Disease

AbstractThe objectives of this study were to 1) screen all sow herds in a region for M. hyopneumoniae, 2) to effectuate an eradication programme in all those herds which were shown to be infected with M. hyopneumoniae, and 3) to follow the success of the screening and the eradication programmes. The ultimate goal was to eradicate M. hyopneumoniae from all member herds of a cooperative slaughterhouse (153 farrowing herds + 85 farrowing-to-finishing herds + 150 specialised finishing herds) before year 2000. During 1998 and 1999, a total of 5067 colostral whey and 755 serum samples (mean, 25 samples/herd) were collected from sow herds and analysed for antibodies to M. hyopneumoniae by ELISA. Antibodies were detected in 208 (3.6%) samples. Two farrowing herds (1.3%) and 20 farrowing-to-finishing herds (23.5%) were shown to be infected with M. hyopneumoniae. A programme to eradicate the infection from these herds was undertaken. During March 2000, a survey was made to prove the success of the screening and the eradication programmes. In total, 509 serum samples were collected randomly from slaughtered finishing pigs. Antibodies to M. hyopneumoniae were not detected in 506 of the samples, whereas 3 samples were considered suspicious or positive. Accordingly, 3 herds were shown to be infected. One of the herds was previously falsely classified as non-infected. Two of the herds were finishing herds practising continuous flow system (CF). Unlike finishing herds which practice all-in/all-out management routines on herd level, CF herds do not get rid of transmissible diseases spontaneously between batches, for which reason a screening was made in the rest of the CF herds (total n = 7). Consequently, 2 more infected herds were detected. In addition to the results of the survey, a decreasing prevalence of lung lesions at slaughter (from 5.2% to 0.1%) and lack of clinical breakdowns indicated that all member herds were finally free from M. hyopneumoniae in the end of year 2000.SammanfattningRegional sanering av Mycoplasma hyopneumoniae från svinbesättningar och dokumentation av sjukdomsfriheten. Syftet för denna undersökning var 1) att analysera (fastställa) infektionsstatus gällande M. hyopneumoniae i alla suggbesättningar i en region, 2) att sanera varje besättning som bedöms vara infekterad med M. hyopneumoniae, 3) att följa analysernas och saneringarnas framgång. Det slutgiltiga målet var att utrota M. hyopneumoniae från alla medlemsbesättningar av ett andelsslakteri (153 smågrisproducerande besättningar + 85 integrerade besättningar + 150 specialiserade slaktsvinsbesättningar) före år 2000. Under år 1998 och 1999 analyserades totalt 5067 råmjölksprov samt 755 serumprov (i medeltal 25 prov/besättning) för antikroppar mot M. hyopneumoniae med ELISA. Antikroppar konstaterades i 208 prov (3.6%). Två smågrisproducerande besättningar (1.3%) och 20 integrerade besättningar (23.5%) bedömdes vara infekterade med M. hyopneumoniae. För dessa besättningar planerades och genomfördes ett saneringsprogram. I mars år 2000 kartlades analysernas och saneringarnas framgång. Totalt undersöktes (analyserades) 509 slumpmässigt tagna serumprov från slaktsvin. Antikroppar mot M. hyopneumoniae konstaterades inte i 506 prov, men tre prov bedömdes vara positiva eller svagt positiva. Det visade sig att 3 besättningar faktiskt var infekterade med M. hyopneumoniae. En av besättningarna visade sig vara en integrerad besättning, som tidigare felaktigt bedömts vara icke-infekterad. Två av besättningarna var slaktsvinsbesättningar med kontinuerlig produktion (KP). I motsats till slaktsvinsbesättningarna med all-in/all-out produktion på besättningsnivån, blir KP besättningarna inte spontant fria från smittsamma sjukdomarna mellan uppfödningspartier. Därför analyserades infektionsstatus också i resten av KP besättningarna (total n = 7). Sålunda konstaterades ännu 2 infekterade besättningar. Resultatet av kartläggningen tillsammans med en förminskning av prevalensen av lungskador vid slakt (från 5.2% till 0.1%) samt brist på kliniska sjukdomsutbrott tyder på, att alla besättningar var slutligt fria från M. hyopneumoniae i slutet av år 2000.

Vulvar Discharge Syndrome in Loosely Housed Finnish Pigs: Prevalence and Evaluation of Vaginoscopy, Bacteriology and Cytology

A total of 21 sow herds were randomly chosen to determine the prevalence of vulvar discharge syndrome (VDS) in loosely housed sows. The median VDS prevalence was low as expected, 0% (range 0-4.5%). Nine of the 655 animals examined (1.4%, 95% CI 0.5-2.3) displayed signs of VDS in 21 non-problem herds. In addition, five VDS problem farms were visited to gather more animals affected with the syndrome in order to estimate which methods of examination are useful. Altogether, 19 VDS animals and 19 healthy controls were found, inspected and sampled. Ten of the VDS animals (53%) and three of the controls (16%) were positive in bacterial culture (p = 0.04) taken with a guarded swab from the anterior vagina. In addition, 94% of VDS animals had a positive vaginoscopic examination result and the corresponding figure in the control sows was 28% (p < 0.0002). Cytological smears were classified as positive in 37% of the case sows and in 5% of the control sows (p = 0.04). Detection of vulvar discharge was associated with vaginoscopic examination findings (p = 0.0005) and with bacteriology (p = 0.04), but not with leucocyte counts (p = 0.07). Susceptibility testing was performed on pure bacterial cultures. Totally, 7 (44%) of 16 isolates were considered to be resistant or showed intermediate susceptibility to at least one of the antimicrobial agents tested (sulpha-trimethoprim and ampicillin). In conclusion, we found vaginoscopy and bacteriology as valid tools in diagnosis of VDS and susceptibility testing of antimicrobial treatments was found to be indicated.