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The study aimed to investigate the possible anti-inflammatory activity of larch sawdust as feed supplement in lactating sows' diet and its possible effect on the prevalence of Postpartum Dysgalactia Syndrome under field conditions. In a Greek farrow-to-finish pig farm, fifteen sows were randomly and equally allocated to a negative control group (NC group), a positive control group (PC group), and a treatment group (LT group). The animals of the first two groups received 99% basic diet and 1% corn starch, while LT group animals received 99% basic diet and 1% larch sawdust. The whole trial period lasted 35 days (7 days prior to farrow - day of weaning). At parturition day, animals of the PC group received 2 ml of an anti-inflammatory drug intramuscularly (meloxicam, Metacam®, Boehringer Ingelheim Vetmedica), while the animals of both other groups, received 2 ml of normal saline. Results showed insignificant differences among experimental groups for parameters such as post-partum rectal temperature and piglets performance. On the contrary, a significant increase of mean milk lactation index was observed in LT and PC groups on the 4th day of lactation period, when compared with NC group (p=0.014). Additionally, mean IL-6 concentrations in blood in the LT group showed a tendency for reduction when compared with those found in NC, and insignificant difference (p>0.05) when compared with those observed in PC group 24 hours postpartum. Moreover, the respective TNFα mean level in the LT group at 24 and 72 hours after parturition was similar to that found in PC group, respectively) and significantly lower than that determined in the NC group (p=0.003, p=0.024. The results suggest a possible anti-inflammatory effect of larch sawdust in sows.

The aim of the present study was to investigate the efficacy of single-dose intradermal vaccination against Mycoplasma hyopneumoniae on a commercial swine unit. A total of 1051 healthy suckling piglets of 28±3 days of age were randomly assigned to one of three experimental groups: (a) intradermal: 346 piglets vaccinated intradermally (Porcilis M Hyo ID Once, Intervet SPAH), (b) intramuscular : 351 piglets vaccinated intramuscularly (Porcilis M1 Intervet SPAH) and (c) controls: 354 piglets injected with a placebo (adjuvant only). Performance parameters such as average daily weight gain (ADG), as well as health parameters and lung lesion scores were monitored from four weeks of age until slaughter. The improvement in ADG over the controls, during the finishing phase, was 27 g/day for the intradermal group and 17 g/day for the intramuscular group. Both intradermal and intramuscular vaccinations were effective in reducing clinical signs and lung lesions caused by M hyopneumoniae. Compared with the controls, approximately 10.4 per cent fewer clinical cases were diagnosed in the intradermal group, and 6 per cent fewer in the intramuscular group, during the finishing period. In conclusion, performance results were better in the vaccinated groups than in the control group, while intradermal vaccination afforded greater protection than intramuscular vaccination, especially with regard to morbidity, lung lesion and pleuritis scores.

The purpose of this study was to assess the efficacy of a probiotic containing Bacillus cereus var. Toyoi spores (Toyocerin) and benzoic acid (VevoVitall) on growth performance and diarrhoea in weaning pigs, against negative controls. The trial groups were as follows: (a) NC group (Negative Controls): No treatment (b) TOYO group: Same feed as in the controls plus Toyocerin at a dose of 1 x 10(9) Bacillus cereus var. Toyoi spores/kg feed, (c) BA group: Same feed as in the controls plus VevoVitall at a dose of 5 g/kg feed (5000 ppm benzoic acid) and (d) TOYO+BA group: Same feed as in the controls plus Toyocerin at a dose of 1 x 10(9) Bacillus cereus var. Toyoi spores and VevoVitall at a dose of 5 g/kg feed. In conclusion, the results of this study indicated that administration of Bacillus cereus var. Toyoi spores at 1 x 10(9)/kg feed or benzoic acid at a dose of 5000 ppm or the combination of 1 x 10(9) Bacillus cereus var. Toyoi spores and 5000 ppm of benzoic acid/kg feed, improved the growth performance parameters and reduced the severity of diarrhoea in weaning pigs.

The aim of the present trial was to investigate the efficacy of Virbamix PE (Virbac SA, France) an appetite enhancer and feed flavouring material containing plant extracts of Origanum vulgaris and Allium sativum, added to the feed at one single dose in the control of proliferative enteropathy (PE) in weaning pigs, in comparison to reference treatment with tiamulin (Tiamutine 6.5 Premix/Ceva Animal Health) group and a negative control group. The trial was conducted on a farm with a previous history of ileitis outbreaks. At weaning day (25 +/- 3 days old / day 0 of the trial) a total of 288 (144 male + 144 female) piglets were selected and allocated into three experimental groups, each group comprising of four pens with 24 piglets in each pen. Group 1 (T1 group) served as negative control group (unmedicated), group T2 received medication in feed at the dose of 1 kg Virbamix PE per tonne of feed and T3 group received 32 ppm of tiamulin. Treatments lasted for six weeks (up to the age of 67 +/- 3 days), and no other antibacterial or growth promoter was added to the feed or drinking water in the same period. Administration of Virbamix PE was found to be effective for the control of PE, as shown by the reduction of prevalence of Lawsonia intracellularis in the intestine at the end of the treatment period, as determined by PCR method comparatively with the T1 group, while no significant difference was found between T2 and T3 groups. The diarrhoea score (DS) was significantly higher (P < 0.05) in the control group in comparison with T2 and T3 groups. However, no significant differences were noticed between T2 and T3 groups during the treatment period (P > 0.05). Treatment of piglets with Virbamix PE and Tiamutine 6.5 Premix resulted in significantly higher body weight and average daily gain (ADG) than in T1 group for the total treatment period (P < 0.05). Conclusively, the results of present study indicate that the use of Virbamix PE, could be an alternative and economic method for the control of PE. Moreover, the use of this product is in accordance with the contemporary consumer demands for more environmentally friendly pig production, satisfying at the same time the producer needs for increased and cost-effective performance.

The mycotoxin zearalenone (zen) impairs fertility in farm animals. The aim of the present study was to investigate the effect of zearalenone and its major metabolite (alpha-zearalenol) on boar semen binding capacity, under in vitro conditions. Extended boar semen was exposed to three different concentrations of zen and alpha-zen (40, 60 and 80 microg ml(-1) of semen) for 1 h. Afterwards, the semen was washed and incubated with homologous oocyte hemizona for 4 h. A significant decrease (P < 0.001) in the number of tightly attached spermatozoa on the hemizona was obtained at concentrations of 60 microg ml(-1) and 80 microg ml(-1) of zen and alpha-zen. In conclusion, zen and alpha-zen affected the sperm-zona interaction by reducing the ability of boar spermatozoa to bind to the zona pellucida., ((c) 2007 John Wiley & Sons, Ltd.)

The purpose of the study was to investigate whether, on farms with both post-weaning multisystemic wasting syndrome (PMWS) and porcine reproductive and respiratory syndrome (PRRS), the PRRS vaccination of sows and their fattening pigs protects against these syndromes. In a farrow-to-finish pig farm with a history of PRRS and PMWS, 200 gilts and sows were allocated to one of two groups of equal size. The first group (C-sow group) was used as untreated controls, while the animals of the second group (V-sow group) were vaccinated with live Porcilis PRRS vaccine. At the next weaning, all piglets of half the sows of the C sow group were vaccinated once at 35 days of age with the vaccine (CV group), while the offspring of the other half of the unvaccinated sows were left unvaccinated (CC group). Similarly, the offspring of half the sows of the V sow group were vaccinated (VV group), while those of the other half of the vaccinated sows were left unvaccinated (VC group). No significant differences in morbidity were observed between the groups during the nursery and finishing phases, while morbidity in the growers was significantly reduced in the CV- and VV-groups (P < 0.05). Growers' mortality was significantly reduced after piglet vaccination when compared with unvaccinated pigs of unvaccinated dams (P < 0.05). Average daily gain and feed conversion ratio were significantly improved in vaccinated piglets compared with those in the unvaccinated groups (P < 0.05).

The efficacy of an inactivated aqueous vaccine against Mycoplasma hyopneumoniae was evaluated at two M hyopneumoniae-infected farrow-to-finish commercial farms (A and B) in Greece. In a prospective, randomised double-blind study, two groups on each farm received intramuscular doses of either the vaccine or the adjuvant when they were one and four weeks of age. The pigs were observed daily for clinical signs of disease; morbidity and mortality were recorded; and bodyweight was recorded at intervals. At slaughter, the lungs of the animals were examined and the chest cavities were examined for signs of pleuritis. No adverse reactions to the treatments were observed in any of the pigs. On farm A the vaccinated pigs were on average 6 kg heavier at slaughter, and on farm B they were on average 4 kg heavier; on both farms the average daily gain of the pigs was greater than that of the unvaccinated pigs. The prevalence and severity of enzootic pneumonia in the affected lungs were significantly lower in the vaccinated than in the unvaccinated pigs.

This study was conducted to determine the in vitro effects of three different concentrations (125, 187.5 and 250 microM in diluted semen) of zearalenone (zen) and alpha-zearalenol (alpha-zen) on boar sperm. Semen parameters such as motility, viability and spontaneous acrosome reaction were evaluated. From the results it was shown that both zen and alpha-zen affected the sperm characteristics significantly (p < 0.05), except for alpha-zen at the low concentration which did not decrease the percentage of live reacted spermatozoa significantly. In conclusion, zen and alpha-zen are directly toxic when they affect boar semen in vitro and consequently decrease the fertilization ability of the sperm. The higher the concentration of mycotoxin tested, the greater the decline of sperm parameters noticed. The influence of mycotoxins was found to be time- and dose-dependent.

The purpose of this study was to investigate the safety and efficacy of a commercial European porcine reproductive and respiratory syndrome virus (PRRSV)-inactivated vaccine after 18-month use in gilts/sows at a farm with high seroprevalence. In a farrow-to-finish farm with 1100 sows, all sows and gilts were systematically vaccinated with the PRRS-inactivated PROGRESSIS vaccine for a period of 18 months. Farm's reproductive and litter characteristics were longitudinally recorded for this period and historically compared with those of the year prior to vaccination. Serology, employing immunoperoxidase monolayer assay, had confirmed a high prevalence of PRRS-specific antibodies in most age groups within the farm prior to vaccination. Seroprevalence during the experiment ranged between 0% and 100% in weaners and growers, but remained at stable high levels (> 93%) in finishing pigs and gilts throughout all 2-year period of serology measurements. No local or systemic vaccine side effects were noted throughout the trial period. Vaccinations had resulted over time in a significant improvement of sow reproductive performance (e.g. reduction of premature farrowings, abortions and increase of farrowing rate) and litter characteristics (e.g. increase of the number of live born and weaned pigs and decrease of stillborn, mummified, weak and splay-legged piglets). It has also been observed that the higher the degree of immunization of a sow, the better the improvement of her reproductive parameters. Sows after vaccination have shown improved characteristics compared to homoparous sows prior to the application of vaccinations in the farm.

This trial's aim was to evaluate the effect of in-feed lincomycin for the control of proliferative enteropathy (PE; also known as ileitis) in growing pigs, in which it is associated with significant morbidity levels. Investigation regarding the efficacy of this substance in growing pigs has never been carried out before in a field trial. The trial farm had a previous history of PE outbreaks. On day 1 of the trial (age of 62 +/- 1.5 days), 240 pigs were divided into two groups of 120 pigs/group which were allocated into five pens of 24 pigs each. Therefore, a randomized block design was used with two experimental groups (T1-T2) and five replicates (pens) per group. T1 group served as negative control (NC) animals which were receiving no medication and conversely T2 group received in-feed lincomycin at the dose of 110 mg/kg of feed. The treatment period lasted for 3 weeks, followed by an observation period of 4 weeks up to the age of 111 +/- 1.5 days which was the end of the grower stage. Administration of lincomycin at a dose of 110 mg/kg of feed had beneficial effects compared with the NC group. The pigs of T2 group showed significant improvement of their production parameters in terms of average daily body gain (ADG) and feed conversion ratio (FCR) not only during the treatment period (ADG: 0.515 +/- 0.050 versus 0.481 +/- 0.071 and FCR: 2.38 +/- 0.05 versus 2.56 +/- 0.08, for T2 and T1 groups respectively), but also during the remaining period until the end of the grower stage (observation period: ADG: 0.687 +/- 0.019 versus 0.646 +/- 0.044 and FCR: 2.58 +/- 0.02 versus 2.74 +/- 0.02 respectively). Other effects in the T2 group refer to the reduction of diarrhoea prevalence (mean pen diarrhoea score during the whole grower stage: 0.200 +/- 0.060 versus 0.632 +/- 0.041 respectively), morbidity rates (morbidity rates during the whole grower stage: 15.83% versus 45.00% respectively) and the reduction of Lawsonia intracellularis prevalence as shown by polymerase chain reaction diagnostic method (at the end of the treatment period: 10.0% versus 60.0% respectively). In conclusion, treatment with 110 mg lincomycin/kg of feed for 21 consecutive days had a beneficial effect on the control of PE in growing pigs.

The objective of this field study was to evaluate in an endemically porcine reproductive and respiratory syndrome (PRRS) virus-infected farm the reproductive performance of sows after their vaccination with a PRRS attenuated vaccine. In a farrow-to-finish pig farm with history of endemic PRRS virus infection, a total of 200 gilts and sows were used. They were divided in 2 groups of 100 animals. The first group was used as untreated controls, while the animals of the second group were vaccinated against PRRS virus using the attenuated Porcilis PRRS vaccine (Intervet International, The Netherlands) based on European strain. All health and reproductive parameters were recorded from the time of vaccination up to next weaning. No adverse systemic or local reactions or side effects relative to vaccination were noted. Compared to controls, vaccinated sows showed significantly improved farrowing rate (89% versus 78%) and a tendency for fewer returns to oestrus, particularly those at irregular intervals. Fewer sows farrowed prematurely and showed post-partum dysgalactia syndrome, but more live pigs were born and weaned in each litter after vaccination. It was concluded that vaccination of sows with Porcilis PRRS attenuated vaccine in farms with endemic PRRSV infection has beneficial effects on their health and fertility.

The aim of this study was to assess the efficacy of BioPlus 2B, a probiotic containing Bacillus licheniformis and Bacillus subtilis spores, on the health status and productivity of sows and their litters. A total of 109 gilts and sows were allocated into two experimental groups, as follows: untreated controls (UC) and BioPlus 2B (same feeding as the UC group plus BioPlus 2B) at a dose of 400 g/ton of feed (equal to 1.28 x 10(6) viable spores/g of feed). Treatment started from the day of allocation (14 days prior to the expected farrowing) up to the weaning day. Homogeneity of the groups was satisfied with regard to the parity. From the results it was evident that BioPlus 2B supplementation of the feed improved gilt/sow performance as shown by: (i) the increase of sow feed consumption during the first 14 days postpartum and (ii) the decrease of sow weight loss during the suckling period. Certain blood and milk parameters were significantly improved, as shown by higher serum cholesterol and total lipids concentrations and higher milk fat and protein content at mid-suckling period. As a consequence, a positive effect was also noticed as regard litter health and performance characteristics in terms of: (i) decrease in piglet diarrhoea score, (ii) decrease in pre-weaning mortality thus leading to increase in the number of weaned piglets per litter and (iii) increase in piglet body weight at weaning. Moreover, BioPlus 2B tended to improve the health status and fertility of sows demonstrating: (i) tendency to a lower proportion of sows with Mastitis-Metritus-Agalactia (MMA) problems and (ii) lower proportion of sows returning to oestrus.

During the past 50 years, procedures for raising food-producing animals have changed. Intensification of food production was necessary to keep prices low and to fulfill market demands for the continuously increasing worldwide population. Intensification of farming procedures produced many new problems, some of which had a considerable impact on public opinion about how animals are raised and how food of animal origin is produced and preserved. "Man made diseases" of animals such as bovine spongiform encephalopathy (BSE); contamination of foods with dioxins either through contamination of animal feeds or from the environment; and increased microbial resistance to drugs used for treatment, for prophylaxis of animals from infectious agents, and for growth promotion are some well-known hazards of intensified farming. Veterinarians working on food-producing animals are faced with an increased demand for foods of high quality and safety in developed countries, and higher quantities in the rest of the world. These qualitative and quantitative changes indicate that they must adjust to these new conditions. They will be most successful if their education is adjusted to meet the challenges that the public has created for them through new concepts of the production of food of animal origin. One such concept is the production of foods under fully certified procedures from the farm to the consumer's table. Food safety measures protecting public health will better be achieved if the education of the future veterinarian includes the principles of Hazard Analysis Critical Control Points (HACCP) starting at farm level. This article provides some market-driven ideas in this direction for European Union (EU) countries, including Greece.

The aim of the study was to assess the efficacy of BioPlus 2B, a probiotic containing Bacillus licheniformis and B. subtilis spores, on the health status and productivity of pigs, during weaning, growing and finishing stages of growth. On a commercial farrow-to-finish farm, five experimental groups were formed, each of 54 weaned piglets. The pigs of the first group (double controls) received normal feed with no probiotic and the pigs of the second group (untreated controls) received BioPlus 2B only during the weaning stage. The pigs of the third, the fourth and the fifth group received the same as the second group feed but, at the growing and at a part of the finishing stages, supplemented with three different doses of Bioplus 2B, a low, medium and high dose, respectively. The results have shown that, compared with the double controls, BioPlus 2B-treated pigs had a lower morbidity and mortality during the whole trial period, compared with the double controls (range from 9.26 to 14.81% versus 25.93% and from 0.00 to 3.70% versus 11.1%, respectively), as a result of the lower incidence of post-weaning diarrhoea due mainly to Escherichia coli. Weight gain, feed conversion ratio and carcass quality of the BioPlus 2B-treated pigs were significantly improved compared with the double controls, whilst the beneficial effects of the probiotic were more pronounced when the medium and high doses were used.

This study was conducted to assess the effect of dietary use of a clinoptilolite-rich tuff (Cp) on health status and performance of weaned, growing and finishing pigs and its compatibility during simultaneous oral administration of antimicrobials (AM) such as enrofloxacin (E) or salinomycin (S). Weaners (720) were assigned in 2 experimental groups and 4 subgroups based on the inclusion or not of Cp and AM in their feed (subgroups: NC, ES, Cp, Cp+ES) in order to evaluate their health status, under PWDS prevailing herd conditions. A second part of the trial aimed to the evaluation of piglet performance under conditions with minimized PWDS herd risks. For this purpose, a second set of 264 weaners were assigned in 2 groups and 4 subgroups, in a respective manner. All piglets remained on-trial until slaughtering age; Cp was incorporated in their feed at a rate of 2% from the day of weaning until slaughtering. The health status evaluation consisted in monitoring piglets for adverse effects related to Cp consumption, average daily diarrhoea scoring during weaning and mortality rate calculations throughout. Performance evaluation included individual weighing at the end of weaning, growing and fattening periods and feed consumption assessments. Average daily gain (ADG), average daily feed intake (ADFI) and feed conversion ration (FCR) on a pen basis were further calculated. Cp ingestion was well tolerated by the piglets. Simultaneous administration of Cp and AM in feed, resulted in less severe forms of PWDS, which had a shorter clinical course (P<0.05). Mortality decreased (P<0.05) during the weaning period due to AM administration. Concerning mean pig body weight at the end of each production phase, both Cp and AM had favorable effects (P<0.05). ADG estimated for the whole observation period was improved (P<0.05) by Cp-use along with AM. FCR improvements (P<0.05) were noticed during the different stages of growth due to AM or Cp administration, while Cp/AM interaction was noticed only at weaning (P<0.05).

The aim of this trial was to evaluate the effect of in-feed doxycycline (DOXY) on the control of ileitis in weaned piglets. On a farm with a previous history of ileitis outbreaks, 288 piglets at the age of weaning (25 +/- 2 days old) were divided into four experimental groups, each group comprising three pens with 24 piglets in each pen. Non-medicated animals served as negative control (NC) group, whereas groups DOXY-50, DOXY-125 and DOXY-250 received doxycycline via feed at 50, 125 and 250 ppm, respectively. Therapy lasted for 14 days followed by an observation period of 28 days. In conclusion, administration of doxycycline at a dose rate of 125 or 250 ppm had beneficial effect compared with the NC group. in terms of the reduction of diarrhoea prevalence, the enhancement of growth performance and the reduction of prevalence of Lawsonia intracellularis in the intestine, as shown either by the PCR method or by specific histopathological examinations. Treatment with 250 ppm of doxycycline for a fortnight interval post-weaning seems to be beneficial leading to better growth rates of piglets not only during treatment period, but also throughout the whole nursery phase.

The aim of this trial was to evaluate the effect of in-feed josamycine on the control of ileitis in weaned piglets. On a farm with a previous history of ileitis outbreaks, 288 piglets at weaning age (25 +/- 2 days old) were allocated into three experimental groups, each group comprising of four pens with 24 piglets in each pen. Group one (T1) served the trial as negative control group (unmedicated), group T2 was administered josamycine at 36 mg/kg of feed and group T3 was administered josamycine at 50 mg/kg of feed. Treatments lasted for 14 days followed by an observation period of 28 days. Administration of josamycine at both inclusion levels tested had a beneficial effect compared with the negative control group, by the reduction of prevalence of diarrhoea, the enhancement of growth performance and the reduction of prevalence of Lawsonia intracellularis in the intestine, as determined either by the PCR method or by specific histopathological examinations. The beneficial effect of josamycine was more pronounced at the inclusion level of 50 mg/kg of feed.

Post-weaning multisystemic wasting syndrome (PMWS) and porcine dermatitis and nephropathy syndrome (PDNS) are two recently described conditions of pigs at the late nursery and fattening stages. The aim of this short communication was to describe the first reported occurrence of these conditions and of porcine circovirus type 2 (PCV2) infection in Greece. The clinical signs, gross post-mortem changes and histopathological changes observed in affected pigs, were similar to those previously described for both PDNS and PMWS. As in previous reports, the lesions were associated with PCV2 infection, which was demonstrated by immunohistochemical and in situ hybridization methods.

The study was conducted to evaluate the effect of the long-term dietary use of a natural zeolite (clinoptilolite, NZ) on health status and reproductive performance of sows/gilts and performance of their litters, along with its compatibility with antibacterials (chlortetracycline, CTC) periodically used in medication programmes. Two hundred and forty sows/gilts and their litters were assigned to two main experimental groups and four subgroups, depending on the inclusion of NZ and CTC in their feed. During the trial, frequent sampling of pregnancy feed for mycotoxicological analysis revealed a high contamination level with zearalenone. No adverse or side effects attributed to NZ were noticed. Furthermore, the combined use of NZ and CTC revealed no clinically apparent interactive effect on the availability of the latter. Reproductive performance was significantly improved by the dietary inclusion of both NZ and CTC. The results also suggested that the beneficial effect of NZ could be additionally considered as an indicator of the amelioration of zearalenone exposure consequences.

The study was conducted to evaluate, under field conditions, the effect of the long-term dietary use of a natural zeolite (clinoptilolite, CLI) and antibacterials (chlortetracycline, CTC) on the concentrations of certain vitamins (vitamin A and vitamin E) and minerals (K, Na, P, Ca, Mg, Cu and Zn) in blood and body tissues of the sow. Twenty-four sows were assigned to two main experimental groups and four subgroups, depending on the presence or absence of CLI and CTC in their feed, respectively. CLI was provided to the sows from weaning, during the service, gestation and lactation periods and up to the date of the next service, while CTC was administered for a 2-week period post-service, as well as for a 2-week period following the allocation of the sows in the farrowing house, around 5 days prior to the expected parturition. Blood samples were collected on the starting day of the trial, on the 30th and the 90th day of each pregnancy, on the day of each parturition and on the day of each weaning. Furthermore, 20 sows were similarly distributed in the same experimental groups and subgroups and at the end of the trial they were slaughtered and liver and kidney samples were collected for biochemical analysis. Neither CLI nor CTC supplementation of the diets had any significant effect on vitamins' and minerals' uptake and their distribution in the body, since there was no alteration in their blood serum and liver/kidney concentrations. Furthermore, no CLI x CTC interaction was noticed.

Post-weaning multisystemic wasting syndrome (PMWS), primarily caused by porcine circovirus type 2 (PCV-2), is an economically important disease of pigs in many countries. A trial was designed to investigate the hypothesis that non-specific immuno-modulation can influence the clinical and pathological expression of PMWS in pigs naturally infected with PCV-2. Eighty-four pigs on a commercial pig farm were allocated to three groups of 28 pigs each, during an outbreak of PMWS. The pigs in the first group received an intramuscular injection of a vaccine against Mycoplasma hyopneumoniae (RespiSure, Pfizer, NY, USA) at each of 7 and 28 days of age, followed by an intramuscular injection of normal saline at 42 days of age. The animals in the second group received, by intramuscular injection, normal saline at 7 days of age followed by a non-specific immuno-modulating drug (Baypamun, Bayer, Leverkusen, Germany) at each of 28 and 42 days of age. The pigs in the third (control) group received an intramuscular injection of normal saline on each of 7, 28 and 42 days of age. The trial was concluded when the pigs had reached the age of 73 days. Clinical signs characteristic of PMWS developed in 42.9% of pigs inoculated with RespiSure and in 50% of pigs treated with Baypamun; six pigs from each of these groups died. Moderate to severe gross and histopathological lesions of PMWS, associated with abundant PCV-2 antigen, were seen in a wide range of tissues of pigs from these groups at the end of the trial. In contrast, only 10.7% of pigs in the control group developed clinical signs and only one died. Mild to moderate lesions and scant PCV-2 antigen were occasionally observed in tissues of control pigs at the end of the trial. This is the first study to demonstrate that non-specific stimulation of the immune system by a vaccine or an immuno-modulator drug can potentiate viral replication and increase the severity of clinical signs during an outbreak of PMWS.

A trial was carried out with HYORESP a Mycoplasma hyopneumoniae (M. hyo) vaccine in order to confirm the benefit of vaccination under field conditions in a commercial industrial farrow-to-finish unit, contaminated with M. hyo. Infection with M. hyo was confirmed through positive blood and colostrum samples [enzyme-linked immunosorbent assay (ELISA) test] combined with positive gross lesions of the lung at slaughter. Two different vaccination schedules were tested. Pigs were randomly allocated to three groups: control non-vaccinated group (n = 130, given a placebo injection at 3, 25 and 70 days of age); early vaccinated group (n = 128, given vaccination at 3 and 25 days of age and a placebo at 70 days of age); late vaccinated group (n = 132, given a placebo at 3 and 25 days of age and vaccination at 70 days of age). Both growth rate and feed conversion ratio were signifcantly (P < 0.05) improved in the vaccinated groups compared with the control group. The lung lesion score was also significantly (P < 0.05) improved in both vaccinated groups. In this trial, it was clearly demonstrated that vaccination is highly effective in improving performance in pig units infected with M. hyo. The improvement in the feed conversion ratio in the vaccinated groups was especially impressive: -0.411 (13% improvement) in the group vaccinated twice at 3 and 25 days of age; -0.162 (5% improvement) in the group vaccinated once at 70 days of age. Performances were better when two shots were given early in life compared with one shot later--probably due to an infection taking place rather early in life for most of the pigs. Moreover, a significant reduction in the cost of supportive (injectable) medication was noticed in vaccinated pigs. In conclusion, HYORESP proved to be a very efficacious tool to control M. hyo in infected herds with its remarkable flexibility that allows the vaccination schedule to be adapted to the specific field conditions.

Twenty-five gilts and sows, after pregnancy confirmation using the ultrasonic method, were randomly divided and allocated to the following five experimental groups: SAL0 = negative controls, SAL20 = 20 mg salinomycin per kg of feed, SAL40 = 40 mg salinomycin per kg of feed, SAL60 = 60 mg salinomycin per kg of feed and SAL80 = 80 mg salinomycin per kg of feed. All animals remained under treatment for two consecutive breeding cycles. The sows were fed a home-mixed balanced feed during gestations and lactations. At the third, tenth and eighteenth day of each lactation, blood and milk samples were collected. Blood samples were analysed for cholesterol and total lipids and milk samples were analysed for the determination of the fat, lactose, protein, ash and totals solids concentrations. In all treated groups, cholesterol concentrations were significantly higher (P < 0.05) compared with the controls. Total lipid concentrations were significantly higher (P < 0.05) in SAL40 and SAL60 groups in comparison with SAL0 and SAL20 groups, during both cycles. Milk fat concentrations were higher (P < 0.05) in treated groups than in the control group; the highest concentrations were observed at SAL40 and SAL60 groups. In all treated groups, concentrations of milk lactose were significantly higher (P < 0.05) than those observed in the negative control group. Milk protein concentrations were significantly higher (P < 0.05) in SAL40 and SAL60 groups compared with the SAL0 group, but there was no significant difference in SAL20 and SAL80 groups in comparison with the SAL0 group. No significant differences were observed concerning milk ash concentrations between all groups. In all treated groups, concentrations of total solids were significantly higher (P < 0.05) in comparison with the control group; the highest concentrations were observed in the SAL40 and SAL60 groups. It is concluded that the use of salinomycin in sow diet, increases concentrations of blood triglycerides and cholesterol and improves the quality of milk, thus reflecting on higher weight gain and survival rate of suckling piglets.

Two hundred and fifty gilts and sows (Dalland parent stock) were divided randomly and allocated into the following five experimental groups: SAL0 = negative controls, SAL20 = 20 mg salinomycin per kg of feed, SAL40 = 40 mg salinomycin per kg of feed, SAL60 = 60 mg salinomycin per kg of feed and SAL80 = 80 mg salinomycin per kg of feed. Each gilt and sow was allocated to one of the five groups after the confirmation of the pregnancy using the ultrasonic method and remained under treatment for two consecutive breeding cycles. Throughout the experimental period several parameters related to sow health status, performance and fertility, as well as to health status and performance of their litters were recorded and calculated. Results indicated that salinomycin improves most of the parameters examined, as it leads to significantly higher (P < 0.05): (i) sow body weight gain during gestation; (ii) number of piglets born alive and weaned; (iii) piglet body weight at birth and at weaning, as well as to significantly lower (P < 0.05): (i) prevalence of thin sow syndrome at weaning; (ii) sow body weight loss during lactation; (iii) weaning-to-oestrus interval; (iv) piglet diarrhoea score during lactation; and (v) preweaning mortality. The best results were obtained at the inclusion levels of 40 and 60 mg salinomycin per kg of feed.

Post-weaning diarrhoea syndrome (PWDS) of piglets is caused mainly by Enterotoxigenic Escherichia coli (ETEC) strains. Six organic acids were tested for their efficacy in the control of PWDS, using a total of 384 weaned piglets, in eight groups, during a 28-day period. One group (negative control) was offered a diet free of antimicrobials, one group (positive control) was offered the same diet medicated with 44 p.p.m. of lincomycin and 44 p.p.m. spectinomycin (Lincospectin 22 premix, Upjohn), and six groups were offered feed supplemented with either 1.0 per cent propionic acid, 1.6 per cent lactic acid, 1.2 per cent formic acid, 1.2 per cent malic acid, 1.5 per cent citric acid or 1.5 per cent fumaric acid. Groups were compared with regard to the appearance of clinical signs, mortality, weight gain and feed conversion. All groups supplemented with organic acids had reduced incidence and severity of diarrhoea, and performed significantly better than the negative control group (P<0.05). At the end of the trial, ETEC strains were detected in the control group not receiving antibiotics but not in the treated group. Organic acids and especially lactic acid are a useful tool in controlling PWDS.

Oedema disease usually occurs after weaning and is due to infection with Enterotoxaemic Escherichia coli strains. A total of 240 weaned piglets were used in five groups during a 28-day period. One group (a negative control) was offered feed free of antimicrobials ad libitum, three groups were offered the same diet ad libitum supplemented with either 1.6 per cent lactic acid, 1.5 per cent citric acid or 50 p.p.m. of enrotloxacin (ENR/Baytril I.E.R. 2 5 per cent, Bayer), respectively. Finally, one group was offered the same diet but the amount offered was restricted during the first 12 days post-weaning. Groups receiving acid or ENR additions to the diet had lower mortality than the negative control group (P<0.05). The three groups on treated feed also showed significantly better growth performance and food conversion ratio than the control group (P<0.05). Both organic acids and medication with 50 p.p.m. of ENR for a 10-day period are useful in controlling and/or preventing post-weaning oedema disease.

The efficacy of Paciflor, a bioregulator containing live Bacillus cereus CIP 5832 spores, was assessed in sows during late pregnancy and lactation, as well as in their piglets up to the growing phase. Two groups each of 30 pregnant gilts and sows received normal feed (T1 group), or feed with 85 g Paciflor per ton feed (T2 group), from 15 days prior to farrowing up to the end of the lactation period. Furthermore, 15 litters of the T1 group and 15 litters of the T2 group, were offered normal feed from the 5th to the 70th days of life (T1.1 and T2.1 groups, respectively), while the remaining 15 litters each of the T1 and T2 groups received the same feed but including Paciflor at a dose of 100 g/ton (from day 5 to day 49) and 50 g/ton (from day 50 to day 70). These pig litters were T1.2 and T2.2, respectively. No differences were seen between the T1 and T2 groups with respect to the clinical observations (loss of appetite, fever, mastitis, metritis and returns to oestrus, treatments applied, deaths, or removals to the slaughterhouse), gestation length, bodyweight of sows at farrowing or litter-size at birth. However, during lactation, the fat content of the dam's milk was increased (0.46% more fat), the body weight loss of sows was reduced and the number of weaned pigs per sow was increased (0.6 more pigs per litter) after administration of Paciflor (P < 0.05). Weaning to service interval was also reduced by 1 day (P < 0.05). Moreover, piglets receiving Paciflor with their feed (T1.2 and T2.2 groups) showed less incidence of scours and lower mortality compared to the untreated piglets (T1.1 and T2.1 groups), particularly those pigs originating from Paciflor-treated dams (T2.2 group) (P < 0.05). Despite the fact that no difference was seen between groups with regard to the amount of feed consumed, the feed conversion ratio of Paciflor-treated piglets (T2.2 and T1.2) was significantly improved compared to that of the untreated piglets (T2.1 and T1.1) (P < 0.05). With respect to weight gain, for the Paciflor-treated piglets, those born to Paciflor-treated mothers (T2.2) were 0.56 kg heavier than those born to untreated dams (T1.2) (P < 0.05). It is concluded that administration of Paciflor in dams during the end of pregnancy and during lactation, as well as to their offspring during suckling and the flat-deck period is beneficial for the survival and growth of the piglets.

Six piglets that had survived experimental infection with encephalomyocarditis virus (EMCV) were treated with dexamethasone for a period of 5 days. The virus had not been detected in excretions of putative carriers for a period of 13-20 days before the treatment. All piglets showed a rise in cardiac isoenzyme (CK-MB) activity, from the first day of treatment, suggesting myocardial damage. Antibody titres against EMCV remained stable or slightly decreased during treatment. EMCV was isolated from blood, nasal and faecal samples from all piglets on days 2 and 3 after initiation of treatment and from various tissues of three piglets. Four contact piglets, that were housed together with the dexamethasone-treated piglets, became infected, indicating that EMCV was shed by treated piglets. It is suggested that recovered pigs may play an important role in the dissemination of EMCV.

Thirteen susceptible piglets, aged 40 days, were divided into two groups and were experimentally infected either with a Greek (myocardial) or a Belgian (reproductive) encephalomyocarditis virus (EMCV) strain (total dose 5 x 10(6) TCID50, intramuscularly and intranasally). Six piglets were placed in the same rooms, 24 h later, as contact controls. The following criteria were studied: ante mortem: clinical signs, serum cardiac isoenzyme activities (CK-MB and LD-1), viraemia, nasal and faecal virus excretion and serological response. Post mortem (after death or euthanasia): gross lesions, virus isolation from tissues, RT-PCR, as well as histopathological and immunohistochemical findings. The Greek strain was more pathogenic, producing mortality, with high cardiac isoenzyme activities and pronounced macroscopic myocardium lesions. The Belgian strain was able to induce mild heart lesions, as detected only by cardiac isoenzyme activity and histopathologically. All contact pigs were infected, within the first 1-2 days of their introduction, that coincided with the period of viral excretion by the experimentally infected pigs (up to the 3rd day post infection). Disease was mild, with no mortality.

Post-weaning diarrhoea syndrome (PWDS) of piglets is caused mainly by enterotoxigenic Escherichia coli (ETEC) strains. A new in-feed probiotic, LSP 122 (Alpharma), containing viable spores of Bacillus licheniformis was tested for its efficacy to control PWDS in piglets in a low health-status farm, using four groups with a total of 256 weaned piglets for a 28-day period. One group (negative control) was offered antimicrobial-free and probiotics-free fed, one group was offered feed supplemented with 10(6)viable spores of Bacillus toyoi (Toyocerin(R)) per gram of feed and two groups were offered feed supplemented with 10(6)and 10(7)viable spores of B. licheniformis per gram of feed, respectively, and were compared with regard to the appearance of clinical signs, mortality, weight gain and feed conversion. The results showed that all groups supplemented with probiotics exhibited a reduced incidence and severity of diarrhoea. Mortality in all probiotic supplemented pigs was significantly lower compared with the negative control group (P<0.05). The evaluation of the weight gain data, as well as feed conversion ratio, indicated that the three treated groups performed remarkably better than the negative control group (P<0.05) and the group receiving the high inclusion of LSP 122 performed better than the two other groups receiving probiotics (P<0.05). No ETEC strains were detected on day 22 in the high inclusion of LSP 122 and Toyocerin groups as compared with the untreated control. It was concluded that the high dosage schedule of LSP 122, providing 10(7)viable spores of B. licheniformis per g of feed, is a very useful agent for the control of PWDS due to ETEC., (Copyright 1999 Harcourt Publishers Limited.)

Four groups of 12 pregnant sows of the same genetic background, with similar litter size, living under the same housing conditions and having the same hygienic and nutritional standards, were used. In control animals (gC), a basic feed was provided, in which the dietary level of alpha-tocopherol was 20 mg/kg of feed and that of selenium (Se) was 0.45 mg/kg of feed (standard ration). Sows in the second group (gE) received basic feed supplemented with 30 mg alpha-tocopherol per kg (50 mg/kg of feed, in total). To those in the third group (gSe) basic feed was provided but additionally they were injected with 30 mg Se (sodium selenite) on days 30, 60 and 90 of pregnancy. For the sows in the fourth group (gESe), basic feed was supplemented with 30 mg alpha-tocopherol per kg. In addition they received 30 mg injectable Se (sodium selenite) on days 30, 60 and 90 of pregnancy. The experiment started on day 30 of pregnancy and lasted until weaning day (28 days post-farrowing). It was found that alpha-tocopherol and selenium act synergistically. Piglets born from sows in gESe had the highest immunoglobulin concentration level up to weaning day. All productive and clinical parameters (number of piglets born/litter, number of weaned piglets/litter, and piglets' average body weight at birth and on weaning day) were greater in these piglets in comparison with the animals of the other groups. Diarrhoea problems were minimal in the piglets in gESe.

A live vaccine based on a European isolate of porcine reproductive and respiratory syndrome virus (Porcilis PRRS) was tested in this study in order to determine the protection of fattening pigs against the respiratory form of the syndrome under field conditions. Ten thousand pigs in an infected farm were vaccinated against PRRS virus at the age of 6 weeks and were compared with non-vaccinated pigs with respect to their health status, mortality, performance parameters (average daily gain, average daily feed intake, feed conversion ratio) and the presence of certain pathogens in their lungs. The results showed that treated pigs became ill less frequently and demonstrated reduced mortality compared with untreated ones. As compared with non-vaccinated animals, PRRS-vaccinated pigs also performed in a better way with respect to the feed conversion ratio (P < 0.05) and average daily gain (P < 0.05), while feed intake was similar for both groups (P > 0.05). Bacteriological examinations of the lungs revealed increased incidence of respiratory bacterial infection in untreated pigs compared with treated ones. A tendency for a faster antibody response was also detected in the vaccinees. The results of the present study show that immunization with a live vaccine does protect fattening pigs against the respiratory manifestations of PRRS.

The neural invasion of two virulent Suid Herpesvirus 1 (SHV1) strains was examined in neonatal pigs with or without maternal immunity. One-week-old pigs with comparable levels of maternal immunity (SN-titer = 12-48) were intranasally inoculated with 10(7.0) TCID50 of either of the Ka or E21 strains. The invasion of the strains was examined in the nasal mucosa and in three neuronal levels of the trigeminal nervous pathway as well as in three levels of the olfactory nervous pathway by virus titration and immunohistochemistry (IHC). In control pigs without specific antibodies, both strains invaded up to the end level of each neural pathway. In pigs with maternal immunity, the Ka strain invaded only up to the 2nd level of each pathway with titers being significantly lower (p<0.05) than in the negative controls. However, the E21 strain invaded up to the end levels in both neural pathways of immune pigs with virus titers being similar to those observed in non-immune pigs (p>0.05). IHC revealed that maternal antibodies can protect against a fibroblast-mediated spread of the Ka strain in the lamina propria of the nasal mucosa, as well as against a local spread of the Ka and E21 strains from neurons to their satellite cells in the trigeminal ganglion. In conclusion, the nature of virus strain determines the invasion of SHV1 within the nervous system of maternally-immune neonatal pigs.

Twenty-two polytocous lactating Chios ewes were used to test the effects of bovine somatotropin (bST) on reproduction, progesterone concentration and LH secretion during estrus. Half of the ewes were injected every second week with 160 mg bST in a prolonged release vehicle, from the fifth day post partum until the end of lactation, while the remaining ones were used as controls. All animals were fed the same amount of ration. Supplementation with bST resulted in an increase of milk production (P<0.05) and an insignificant trend for delayed resumption of normal estrous cycles. Although there were no differences between groups, there was also a tendency for the bST group to display lower progesterone concentrations during the first three fortnights after the onset of normal estrous cycles and higher ones during the last three fortnights of the experiment, compared with the control group. Duration of the first normal luteal phase after delivery of the bST group was found to be shorter compared with the control group (P<0.05). After estrous synchronization the bST group showed a shorter estrus compared with the control group (P<0.05). Average and baseline LH concentrations during synchronized estrous in the bST group was lower (P<0.001) compared with the control group. Additionally, the conception rate did not differ between the two groups. This study supports the concept that the beneficial effects of bST treatment on milk production outweigh the potential deleterious effects on reproduction.

The present study investigates the changes in blood cholesterol and total lipids concentrations, as well as changes in milk fat, protein, lactose and total solids content of sows after the long-term administration of virginiamycin (VM) in the feed. Seventy-two (72) healthy Dalland gilts, in 18 groups of four (2 + 2) siblings were used in total. The gilts of each group of siblings were randomly allocated to one of the following four dietary treatments: VM0 = negative control, virginiamycin 0 mg/kg, VM20 = virginiamycin 20 mg/kg feed, VM40 = virginiamycin 40 mg/kg feed and VM60 = virginiamycin 60 mg/kg of feed. Treatments started at the age of 6 months covering three complete breeding cycles (up to the third weaning). The first eight groups of siblings (eight gilts per treatment/32 gilts in total) were used for blood sampling (blood group), while the remaining 10 groups of siblings (10 gilts per treatment/40 gilts in total) were used for milk sampling (milk group). Feeds given at insemination, pregnancy and lactation did not contain any other antibacterial or performance enhancer. The results indicate that all three levels of VM supplementation of gilt/sow feed influenced certain blood parameters by increasing (P < 0.05) both cholesterol and total lipids concentrations on the 30th and 60th day of each pregnancy, at each farrowing and at each weaning. The effect of dietary VM on these blood parameters remained constant throughout three consecutive parities. Moreover, the results indicate a beneficial effect of dietary VM on the milk quality of the sows during the third lactation by increasing (P < 0.05) (i) the mean fat content, (ii) the mean protein content, (iii) the mean lactose content and (iv) the mean total solids content. The highest (P < 0.05) levels in both blood and milk parameters were noticed at the inclusion level of 40 mg/kg of feed.

Virginiamycin (VM), a compound with proven performance-promoting properties in pigs, can also be considered as sow performance enhancer. The present dose titration study investigates the long-term effects of VM on gilt/sow and litter performance. A total of 140 healthy gilts, in 35 sets of 2 + 2 siblings each, were used in this trial; gilts in each set were randomly allocated to the four treatments (35 gilts per each treatment group): VM0 = negative control, virginiamycin 0 mg/kg, VM20 = virginiamycin 20 mg/kg, VM40 = virginiamycin 40 mg/kg and VM60 = virginiamycin 60 mg/kg of feed. VM was added to the gilt/sow feed for a period starting from 6 months of age up to conception of the fourth parity, covering three complete breeding cycles (pregnancy, lactation and weaning-to-conception interval). The feed given did not contain any other antibacterial agent or performance enhancer. Piglets were given exactly the same quantity of creep feed from the fifth day onwards; it did not contain any antibacterial agent or performance enhancer. The lactation period was the same in all gilts/sows (21 days). Results indicate that VM supplementation of the feed improved gilt/sow performance by: (i) increasing (P < 0.05) the mean body weight at each farrowing, (ii) decreasing (P < 0.05) the mean weight loss from farrowing to weaning, and (iii) decreasing (P < 0.05) the mean weaning-to-conception intervals. VM supplementation of gilt/sow feed also resulted in improved litter size and litter performance in terms of: (i) a higher (P < 0.05) mean number of piglets born alive at each birth, (ii) a higher (P < 0.05) mean number of piglets weaned, (iii) a higher (P < 0.05) mean piglet body weight at each birth, and (iv) a higher (P < 0.05) mean piglet body weight at each weaning. These beneficial effects of VM were more pronounced in the VM40 group.

Post weaning diarrhoea syndrome (PWDS) and wasting pig syndrome (WPS) are two entities of the pig industry induced by stress factors occurring at the early weaning and further complicated by opportunistic pathogens. In the present paper we examine--through one pilot and one final trial--whether prevention of these two syndromes can be achieved in the field by immunomodulation of the pig e.g., by improving its non-specific immunological response. In both trials two groups of early weaned piglets were submitted to the treatments. In the pilot trial the first group received no treatment and served as controls and the animals of the second group were injected twice with an inactivated Parapoxvirus based immunomodulator (Baypamun, Bayer, Germany). In the final trial the first group of piglets received no treatment and served as a control group. The animals of the second group were injected twice with a freeze-dried immunomodulator (Baypamun). Piglets were compared with regard to the severity of PWS, mortality, growth performance parameters, and for the presence of pathogens in their faeces. The results have shown that Baypamun treated piglets performed significantly better than negative control piglets in all the parameters examined. It was concluded that stimulation of the non-specific immunity of piglets may be helpful in preventing the appearance of PWDS and WPS in the field.

The aim of this study was to evaluate the effect of different antibiotics used as growth promoters on the control of porcine intestinal adenomatosis when administered in weaning, growing and fattening pig diets, according to Annex I of the European Union directive (70/524/EEC and its subsequent amendments to date) for the use of feed additives. On a farm with a previous history of proliferative enteropathy outbreaks, 648 weaned piglets (23 days old) were divided into nine experimental groups according to bodyweight and sex ratio, each group comprising four pens with 18 pigs in each pen. One group served the trial as a negative (unmedicated) control: another (the positive control) received monensin via feed at 100 p.p.m. up to the end of the growing phase (107 days old) and 50 p.p.m. up to slaughter age (156 days old). The remaining seven groups were offered feed with the addition of the following antibiotics: virginia-mycin (50-20 p.p.m.), avilamycin (40-20 p.p.m.), spiramycin (50-20 p.p.m.), zinc bacitracin (50-10 p.p.m.), avoparcin (40-20 p.p.m.), tylosin (40-20 p.p.m.) and salinomycin (60-30 p.p.m.), respectively. The performance of the pigs in the positive control group was very satisfying and among the highest in the trial, verifying earlier field studies. As a general conclusion it seems that all tested growth promoters had a beneficial effect compared with the untreated control, indicated by the decrease of mortality rate, the elimination of diarrhoeal incidence and the enhancement of growth performance, although the proliferative enteropathy control achieved by each substance was not always satisfactory. More specifically, the antibiotic growth promoters tested can be scaled according to their total efficacy as follows: 1. Salinomycin, tylosin, spiramycin; 2. Virginiamycin, zinc bacitracin, avilamycin; and 3. Avoparcin. Finally, it is considered that part of the growth promotion efficacy of the tested substances is due to their potential capacity to control porcine intestinal adenomatosis; thus, in future growth performance trials, the disease background of the trial farms must be examined, especially for porcine enteropathy challenges.

Oedema disease (OD) usually occurs after weaning and is due to infection with (ETEEC) enterotoxaemic Escherichia (E.) coli. This study further examines the efficacy of three different in-feed usage programmes of enrofloxacin (ENR/Baytril I.E.R. 2.5%), on the control of post weaning OD in piglets. The recommended in-feed dosage of ENR for this clinical indication, i.e. 50 p.p.m., was used. Five groups with a total of 240 weaned piglets for 28 days period were used in this trial. One group (negative control) was offered feed free of antimicrobials, one group was offered feed as that of the negative control group except that the feed consumption was restricted for the first 12 days post weaning, and three groups were offered feed ad libitum medicated with 50 p.p.m. of ENR starting 7 days after weaning for 5, 7 and 10 days, respectively, and were compared with regard to their performance. Mortality was lower compared to the negative control group in all ENR treatments (P < 0.05). The evaluation of the growth performance data, as well as feed conversion ratio, indicated that the three treated groups performed remarkably better than the control group (P < 0.05). It was concluded that a strategic medication initiated 7 days post weaning with 50 p.p.m. of ENR and usually for a 10 day period is useful in controlling and/or preventing post weaning OD due to ETEEC.

Post weaning diarrhoea syndrome (PWDS) in piglets is caused mainly by enterotoxigenic Escherichia (E.) coli (ETEC) strains. Six different in-feed usage programmes of enrofloxacin (ENR/Baytril; I.E.R. 2.5%) were tested for their efficacy on the control of post weaning colibacillosis in piglets, using seven groups with totally 336 weaned piglets for a 28 day period. One group (negative control) was offered feed free of antimicrobials, three groups were offered feed medicated with 50 ppm of ENR starting on weaning day for 5, 7 and 10 days respectively, three groups were offered feed medicated with 50 ppm of ENR starting 7 days post weaning for 5, 7 and 10 days respectively, and were compared with regard to the appearance of clinical signs, mortality, weight gain and feed conversion. The results showed that all ENR treatments reduced the incidence and severity of diarrhoea. Mortality was similar in all ENR treatments, but in the groups where the ENR was added for 10 days immediately after weaning and/or 7 days post weaning for 7 and 10 days respectively was lower compared to the negative control group (P < 0.05). The evaluation of the weight gain data, as well as feed conversion ratio indicated that the six treated groups performed remarkably better than the control group (P < 0.05). No ETEC were detected on days 21 and 28 in all ENR groups contrary to the untreated control. It was concluded that a strategic medication initiated 7 days post weaning with 50 ppm of ENR and only for 7 and 10 days period of time is a useful tool in controlling PWDS due to ETEC.

The degree to which maternally derived antibodies may affect neural invasion of Aujeszky's disease virus (ADV) in neonatal pigs was examined. One-week-old pigs with different levels of maternal immunity were inoculated intranasally with 10(7.0) TCID50 of the Ka strain. The invasion of the virus was studied in both the trigeminal neural pathway (nasal mucosa, trigeminal ganglion = 1st level, pons/medulla = 2nd level and cerebellum/thalamus = 3rd level) and the olfactory neural pathway (olfactory mucosa = 1st level, olfactory bulb = 2nd level and lateral olfactory gyrus = 3rd level) by virus titration and immunohistochemistry (IHC). In control pigs without specific antibodies, virus invaded all neuronal levels in both neural pathways. In pigs with a low concentration of maternal antibodies (SN-titer = 2-3), virus infected all neuronal levels in both neural pathways but, compared to the controls, virus titers were significantly lower (approximately 2 log10) in the trigeminal pathway. In pigs with a high concentration of maternal antibodies (SN-titer = 272-384), virus reached the 2nd neuronal level of the olfactory pathway while no neural tissue had been infected in the trigeminal pathway. Virus titers in the affected neuronal levels of the latter pigs were significantly lower than in the controls. IHC revealed, in non-immune pigs, a fibroblast-mediated spread of the virus in the nasal lamina propria, and a local spread of the virus from neurons to their satellite cells in the trigeminal ganglion. Such a spread of the virus was rarely seen in the nasal mucosa and in the trigeminal ganglion of passively immune pigs. These findings suggest that, in the presence of maternal immunity, defence mechanisms operate at these sites. In conclusion, we can state that a correlation exists between the level of maternal immunity and the protection against invasion of ADV in the nervous system of neonatal pigs.

Optimal reproductive performance of gilts is an economically important characteristic which is influenced amongst others by the general health condition of the animal. In the present pilot study, we examined whether reproductive performance of gilts that were transported from a breeding to a commercial farm can be improved by paramunization, e.g. by enhancing the non-specific immunological response of the animal. Three groups of gilts were submitted to various treatments as follows. The first group received no treatment and served as the control group. The gilts of the second group were injected twice with a paramunity inducer derived from a sheep parapoxvirus (Baypamun liquid, Bayer, Germany), once 2 days before the transport and a second time 2 h before departure. The gilts of the third group were treated as those of the second group, but received an additional injection 2 days after their arrival at the commercial farm. Gilts were compared up to their first farrowing with regard to the appearance of oestrus, the number of the gilts which became pregnant, and the cost of supportive medication. Their litter size at farrowing, the number of piglets born alive and the litter weight have also been recorded. The results show that the number of gilts that showed oestrus and became pregnant was increased after Baypamun liquid treatment, particularly in the third group. The cost of supportive medication per gilt was much lower in treated groups compared to untreated animals. The treatment did not have a significant effect on the total number of piglets born, but some beneficial effect was seen in the number of piglets born alive and the average piglet weight at birth of gilts treated three times with Baypamun liquid. It was concluded that paramunization of gilts at the time of transport may improve their reproductive performance.

This field trial was designed to investigate whether the incorporation of zinc bacitracin into pig feed would prevent porcine intestinal adenomatosis. Two hundred-and-eighty-eight weaned pigs on a farm with a previous history of the disease were divided into 16 pens of 18 pigs. Two dietary regimens of zinc bacitracin were tested: from weaning up to 100 days of age, either 300 or 200 ppm zinc bacitracin were incorporated; from 100 to 125 days of age, either 200 or 100 ppm zinc bacitracin were added; and from 125 to 156 days of age (slaughter), either 100 or 50 ppm zinc bacitracin were added. The results were compared with a positive control group which received 60, 60 and 30 ppm salinomycin during the same periods, and with a negative control group which received no antibacterial and/or performance enhancer. The mortality, diarrhoea scores, average daily weight gains, average daily feed intakes and feed conversion ratios of the pigs were assessed. At slaughter, samples of ileum were taken from eight randomly selected pigs per group for bacteriological and histopathological examinations. The three treated groups all performed better than the control group, and the group receiving the high dose regimen of zinc bacitracin performed significantly better than the groups receiving the low dose of zinc bacitracin or salinomycin.

The ability of salinomycin to control Clostridium perfringens type C infection in sows and their offspring was examined under field conditions. Two groups of sows and their offspring were offered feed either medicated with 60 ppm salinomycin or free of antibiotics, and their performance was compared. The number of piglets with diarrhoea, the duration of the diarrhoea, and the mortality of the piglets during the lactation period were markedly lower in the group given salinomycin. In addition, laboratory examinations showed that the numbers of carrier piglets and sows were reduced after treatment with Salinomycin. Finally, the sows treated with salinomycin lost less weight during the lactation period and weaned more and heavier piglets than the untreated sows. It was concluded that salinomycin incorporated in the diet can be used for controlling C perfringens type C infection in sows and their offspring.

Salinomycin (SAL), an ionophorous polyether antibiotic with growth promoter properties in pigs, has proved to be effective in controlling swine dysentery, porcine intestinal adenomatosis, and porcine haemorrhagic enteropathy. This study examines the ability of SAL to control C. perfringens type-A infection in growing pigs under field conditions. For 2 months, two groups of weaned pigs were offered feed either free of antibiotics, or medicated with 60 ppm and 30 ppm SAL for the first and second month respectively, and were compared with regard to their performance. The results showed that, whilst treatment did not have an effect on the mortality of pigs, the duration of pig diarrhoea during the trial period has been markedly reduced in the SAL group. Laboratory examinations have additionally shown that the number of carrier piglets has been reduced by SAL medication. Finally, treated pigs gained more weight and had a better feed-conversion ratio than untreated pigs during the 2-month trial period. It was concluded that SAL at the registered dose range, used as performance enhancer, can be helpful in controlling C. perfringens type-A infection in growing pigs.

The effects of amperozide on sow performance when administered as a single intramuscular injection of 1 mg kg-1 at the time of either farrowing or weaning, or on both occasions were evaluated. Treatments were given during the rearing of two consecutive litters with each individual sow remaining on the same treatment throughout the trial. In total, 64 sows, 16 per treatment group, were used to investigate the effects on weight loss during lactation, mastitis-metritis agalactia (MMA) and duration of the reproductive cycle. Untreated control sows lost more weight (2 to 3 kg) during lactation than sows treated with amperozide at farrowing. No clinical outbreak of MMA was recorded in the amperozide groups dosed at the time of farrowing. The number of empty days was decreased (about three days) in sows treated with amperozide at weaning. Furthermore, pre-weaning mortality decreased (8 per cent) and piglet growth rate improved (6 per cent) when sows were treated with amperozide at farrowing. The results suggest that amperozide improves the health status and productivity of sows by reducing their emotional responses to novel or threatening situations.

Sixty sows suffering from typical post-weaning TSS were divided into three groups: (1) 20 as negative controls (NC); (2) 20 as positive controls (PC) treated with vitamins, trace elements and antibiotics; and (3) 20 injected with amperozide (2 mg/kg body weight), a new neuroleptic compound with antistress and anxiolytic properties. Amperozide treated sows fully recovered (P less than 0.05) and 80% became pregnant, while figures for the PC and NC groups were only 15% and 10% respectively. Mortality was up to 50% in the NC, 40% in the PC and only 15% in the amperozide treated group (P less than 0.05). These field results warrant further studies in unravelling the aetiology and prevention of this condition.