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.

The effect of vulvar discharge syndrome (VDS) on sow and gilt fertility was studied on 26 farms. Of 824 animals inspected in 21 randomly selected and five VDS problem farms, 19 (2.3%) were afflicted with VDS. Altogether 542/799 of the examined animals (67.8%) farrowed thereafter. Nine of the 19 VDS animals (47.4%) and 533/780 non-VDS animals (68.3%) farrowed at the first chance after the examination (p = 0.05). None of the unmated gilts in this study had VDS. Environmental and individual factors likely to be associated with fertility and VDS were tested. In multivariate analysis, factors associated with farrowing were VDS, reproductive status, availability of roughage and confinement to individual stalls. None of the variables tested was associated with VDS. However, all of the VDS problem farms were overcrowded and had concrete, partly slatted floors with little or no bedding. The median value of haptoglobin (Hp) was 2.5 (range 1.3-3.1) g/l in VDS animals and 2.3 (0.5-4.3) g/l in controls (p = 0.6). The median C-reactive protein (CRP) in VDS animals was 30.3 (3.3-171.3) mg/l and in controls 25.9 (3.3-361.1) mg/l (p = 0.7). In conclusion, VDS decreased fertility of gilts and sows in the absence of a systemic acute-phase response, as indicated by stable concentrations of Hp and CRP.

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.

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).

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.