Mycoplasma hyopneumoniae vaccination at or shortly before weaning under field conditions: a randomised efficacy trial.

This study assessed the efficacy of two different Mycoplasma hyopneumoniae vaccination programmes in relation to the time of weaning. Eight hundred and twenty-eight piglets were randomly divided into three groups: group V1 was vaccinated three days before weaning, group V2 at weaning (21 days of age) and group NV was left non-vaccinated. Vaccinations were performed using Ingelvac MycoFLEX. After the nursery period, 306 pigs were allocated to fattening unit (F1) and 501 pigs to a second unit (F2). Efficacy was evaluated using performance parameters and pneumonia lesions at slaughter. Statistically significant differences were obtained in F2 where group V1 had a higher average daily weight gain compared to groups V2 and NV for the entire study period (17 and 18 g/day, respectively) and the fattening period (26 and 36 g/day, respectively) (P<0.05). Considering respiratory disease scores for both fattening units, group V1 was the only group where coughing severity did not increase significantly between placement and the end of the fattening period (P>0.05). Between groups, there were no statistically significant differences for the average lung lesion scores (V1=3.44; V2=4.61; NV=4.55, P>0.05) and the prevalence of pneumonia (V1=35.0 per cent; V2=38.0 per cent; NV=41.4 per cent, P>0.05). Overall, vaccination against M hyopneumoniae before weaning provided numerically better performance than vaccination at weaning, but did not reach statistical significance. An influenza outbreak in F1 and the presence of coexisting mixed respiratory infections in both F1 and F2 could have possibly influenced the performance of both vaccinated groups across all measured parameters.

Impact of particulate matter and ammonia on average daily weight gain, mortality and lung lesions in pigs.

The present study investigated the simultaneous influence of particulate matter (PM10) and ammonia (NH3) on performance, lung lesions and the presence of Mycoplasma hyopneumoniae (M. hyopneumoniae) in finishing pigs. A pig herd experiencing clinical problems of M. hyopneumoniae infections was selected. In total, 1095 finishing pigs of two replicates in eight compartments each were investigated during the entire finishing period (FP). Indoor PM10 and NH3 were measured at regular intervals during the FP with two Grimm spectrometers and two Graywolf Particle Counters (PM10) and an Innova photoacoustic gas monitor (NH3). Average daily weight gain (ADG) and mortality were calculated and associated with PM10 and NH3 during the FP. Nasal swabs (10 pigs/compartment) were collected one week prior to slaughter to detect DNA of M. hyopneumoniae with nested PCR (nPCR). The prevalence and extent of pneumonia lesions, and prevalence of fissures and pleurisy were examined at slaughter (29 weeks). The results from the nasal swabs and lung lesions were associated with PM10 and NH3 during the FP and the second half of the FP. In the univariable model, increasing PM10 concentrations resulted in a higher odds of pneumonia lesions (second half of the FP: OR=8.72; P=0.015), more severe pneumonia lesions (FP: P=0.04, second half of the FP: P=0.009), a higher odds of pleurisy lesions (FP: OR=20.91; P<0.001 and second half of the FP: OR=40.85; P<0.001) and a higher number of nPCR positive nasal samples (FP: OR=328.00; P=0.01 and second half of the FP: OR=185.49; P=0.02). Increasing NH3 concentrations in the univariable model resulted in a higher odds of pleurisy lesions (FP: OR=21.54; P=0.003) and a higher number of nPCR positive nasal samples (FP: OR=70.39; P=0.049; second half of the FP: OR=8275.05; P=0.01). In the multivariable model, an increasing PM10 concentration resulted in a higher odds of pleurisy lesions (FP: OR=8.85; P=0.049). These findings indicate that the respiratory health of finishing pigs was significantly affected by PM10.

Efficacy of vaccination against Actinobacillus pleuropneumoniae in two Belgian farrow-to-finish pig herds with a history of chronic pleurisy.

The efficacy of an Actinobacillus pleuropneumoniae subunit vaccine based on ApxIA, ApxIIA, ApxIIIA and OMP-2 (Porcilis App, MSD) was investigated in two farrow-to-finish pig herds (A and B) affected by chronic pleurisy. In total, 1161 pigs were included. At three weeks of age, the pigs were randomly allocated to non-vaccinated control (NV; n=580) and vaccinated (V; n=581) groups. At 6 and 10 weeks of age, pigs were injected with Porcilis-APP (V group) or adjuvant (NV group). At slaughter (26 weeks), pleurisy and pneumonia lesions were assessed. All pigs were weighed individually at 6 and 26 weeks of age, and average daily weight gain (ADG; g/pig/day) was calculated. Mortality and days of additional treatment (DAT) were registered during the whole experiment. Data were analysed using binary logistic regression or analysis of variance for proportions or continuous variables, respectively. The prevalence of pleurisy and pneumonia was (NV-A=19.3, V-A=7.9, (P=0.000); NV-B=17.9, V-B=0.7, (P=0.000)) and (NV-A=42.4, V-A=21.2, (P=0.000); NV-B=46.7, V-B=19.0, (P=0.000)), respectively. The ADG was NV-A=632±157, V-A=647±91, (P=0.162); NV-B=660±115, V-B=670±82, (P=0.232). The mortality during the experiment was NV-A=5.7, V-A=1.8, (P=0.015); NV-B=2.3, V-B=1.0, (P=0.170) per cent. The DAT was: NV-A=15.04±1.41, V-A=14.95±0.67, (P=0.010); NV-B=21.68±2.43, V-B=16.99±0.62, (P=0.000). The present study showed a significant reduction of the prevalence of pleurisy and pneumonia, and antimicrobial use in V pigs from both herds, and in mortality in V pigs from one herd.

Efficacy of early Mycoplasma hyopneumoniae vaccination against mixed respiratory disease in older fattening pigs.

The present field study investigated the efficacy of early Mycoplasma hyopneumoniae vaccination in a farrow-to-finish pig herd with respiratory disease late in the fattening period due to combined infections with M hyopneumoniae and viral pathogens. Five hundred and forty piglets were randomly divided into three groups of 180 piglets each: two groups were vaccinated (Stellamune Once) at either 7 (V1) or 21 days of age (V2), and a third group was left non-vaccinated (NV). The three treatment groups were housed in different pens within the same compartment during the nursery period, and were housed in different but identical compartments during the fattening period. The efficacy was evaluated using performance and pneumonia lesions. The average daily weight gain during the fattening period was 19 (V1) and 18 g/day (V2) higher in both vaccinated groups when compared with the NV group. However, the difference was not statistically significant (P>0.05). The prevalence of pneumonia was significantly lower in both vaccinated groups (V1: 71.5 and V2: 67.1 per cent) when compared with the NV group (80.2 per cent) (P<0.05). There were no significant differences between the two vaccination groups. In conclusion, in the present herd with respiratory disease during the second half of the fattening period caused by M hyopneumoniae and viral infections, prevalence of pneumonia lesions were significantly reduced and growth losses numerically (not statistically significant) decreased by both vaccination schedules.

Efficacy of in-feed medication with chlortetracycline in a farrow-to-finish herd against a clinical outbreak of respiratory disease in fattening pigs.

The efficacy of chlortetracycline (CTC) in-feed medication to treat pigs with clinical respiratory disease was investigated in a farrow-to-finish pig herd infected with Mycoplasma hyopneumoniae, and with clinical respiratory disease in growing pigs. In total, 533 pigs were included. The animals were vaccinated against M hyopneumoniae and porcine circovirus type 2 at weaning. At onset of clinical respiratory disease, they were randomly allocated to one of the following treatment groups: chlortetracycline 1 (CTC1) (two consecutive weeks, 500 ppm), chlortetracycline 2 (CTC2) (two non-consecutive weeks, with a non-medicated week interval in between, 500 ppm) or tylosin (T) (three consecutive weeks, 100 ppm). Performance (daily weight gain, feed conversion ratio), pneumonia lesions at slaughter and clinical parameters (respiratory disease score) were assessed. Only numeric differences in favour of the CTC2 group were obtained for the performance and the clinical parameters. The prevalence of pneumonia lesions was 20.5, 13.1 and 23.0 per cent (P<0.05) for the CTC1, CTC2 and T groups, respectively. The study demonstrated that CTC, when administered at onset of clinical respiratory disease via the feed at a dose of 500 ppm during two alternative weeks, was able to decrease the prevalence of pneumonia lesions, and numerically reduce performance losses and clinical signs.

Efficacy of florfenicol injection in the treatment of Mycoplasma hyopneumoniae induced respiratory disease in pigs.

This study investigated the efficacy of a single intramuscular injection of a new formulation of florfenicol to treat clinical respiratory disease following experimental Mycoplasma hyopneumoniae infection. M. hyopneumoniae-free piglets were allocated to three groups, namely, a treatment group (TG) and a positive control group (PCG), which were both inoculated endotracheally with a highly virulent isolate of M. hyopneumoniae, and a negative control group. At the onset of clinical disease, the TG received a single injection of florfenicol (30 mg/kg). All pigs were euthanased 4 weeks post-infection. Clinical symptoms were significantly reduced in the TG in comparison with the PCG. Average daily gain, feed conversion ratio, mortality and lung lesions were improved in the TG compared to the PCG, but the differences were not statistically significant.

Comparison of oral versus parenteral iron supplementation on the health and productivity of piglets.

The aim of this study was to compare oral iron supplementation in feed with a standard iron injection and assess the impact on the health and productivity of pigs. The reliability of a quick test (HemoCue) for the measurement of blood haemoglobin concentration was also investigated. Three pig herds, with a total of 88 sows and their piglets, were included in the study. Piglets in treatment group O were fed a special iron-rich feed on days 2 to 4, 5 to 7 and 8 to 12 of lactation using a specially designed feeding device. Piglets in group IM received 200 mg of an iron dextran complex intramuscularly at three days of age. Haemoglobin concentrations and performance of the piglets were compared between groups. The mean haemoglobin concentrations in pigs at weaning were 131.4 and 116.4 g/l for pigs in groups O and IM, respectively (P<0.01). Daily weight gain (253.9 v 248.8 g/day) and piglet mortality (11.4 v 12.2 per cent) were slightly better in group O than in group IM (P>0.05).