The effect of josamycine on the control of ileitis in weaned piglets under field conditions.

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.

First report of post-weaning multisystemic wasting syndrome and porcine dermatitis and nephropathy syndrome in pigs in Greece.

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 effects of immuno-modulation on the clinical and pathological expression of postweaning multisystemic wasting syndrome.

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.

The effect of salinomycin on certain blood parameters and milk quality of lactating sows.

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.

The effect of salinomycin on health status and performance of sows and their litters: a dose titration study.

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.

Field study on the efficacy of two different vaccination schedules with HYORESP in a Mycoplasma hyopneumoniae-infected commercial pig unit.

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.

Effects of alpha-tocopherol and selenium on pregnant sows and their piglets' immunity and performance.

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 dose titration study on the effect of virginiamycin on gilt/sow and piglet performance.

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.

Effect of an inactivated Parapoxvirus based immunomodulator (Baypamun) on post weaning diarrhoea syndrome and wasting pig syndrome of piglets.

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.

Control of proliferative enteropathy in growing/fattening pigs using growth promoters.

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.

Effect of a paramunity inducer on reproductive performance of gilts.

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.

The effect of salinomycin on the control of Clostridium perfringens type-A infection in growing pigs.

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.