Detection of Mycoplasma bovis with an improved pcr assay

A Mycoplasma bovis species-specific PCR assay has been developed with improvement of a previously described method (Ghadersohi et al., 1997). This test and its semi-nested version (Hayman and Hirst, 2003) did not function at all in our hands. A new reverse primer (Mbr2) was designed using previously published sequence data. For testing specificity, DNA was extracted from the most frequently occurring mycoplasma species and bacteria of bovine origin. The new PCR detected only Mycoplasma bovis. Moreover, no cross-reaction was observed with the genetically closest relative species, M. agalactiae. The target organism could be detected in a dose as low as 150 CFU ml(-1) in broth cultures using ethidium-bromide-stained agarose gels.     

Differentiation of mycoplasma gallisepticum strains using molecular methods

Increasing use of Mycoplasma gallisepticum (MG) live vaccines has led to a need for the differentiation of MG strains. The MG strains MK-7, MS-16, S6, FS-9 and R strains and the MG live vaccine strain F were compared by random amplification of polymorphic DNA (RAPD) in this study. Using RAPD, different patterns were found among the MG strains. In addition to this, we examined the differentiating potential of polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) primers targeted at the crmA, crmB, crmC, gapA, mgc2 and pvpA genes encoding cytadherence-related surface proteins. These proteins may take part in the pathogenesis of MG-induced disease. Differentiation of strain F is based on the identification of restriction enzyme sites in the PCR amplicons. Using HphI enzyme, crmC PCR amplicons produced different RFLP patterns. Digestion of amplicons of gapA-specific PCR with MboI enzyme also produced distinct patterns. Differences were observed among strains R and F by digestion of mgc2 PCR amplicons with HaelIl and VspI enzymes and digestion of pvpA PCR amplicons with AccI, PvulI and ScrFI endonucleases. This method can be used for the rapid differentiation of vaccine strain from wild strains. Differentiation of MG strains is a great advantage for diagnosticians or practitioners and it is useful for epidemiological studies.     

Development of a computed tomographic calibration method for the determination of lean meat content in pig carcasses

Sixty left sides of pig carcasses were scanned by spiral computed tomography (CT) to measure lean meat weight and percentage. The carcasses were fully dissected and scanned to develop a calibration protocol. Different image analyses were performed on the basis of anatomically defined scans, direct volumetric estimation, body- and grey-scale ranges and using Partial Least Squares (PLS) regression of data provided by CT. The R2 values of the calibrations for lean meat weight were 0.874, 0.976, 0.983 and 0.992, respectively, depending on the method applied. The PLS proved to be the best approach with a calibration RSD of 232 g. When changing from lean meat weight to percentage, the statistical goodness drops-to a very small extent (R2 = 0.988, RSD = 0.56). According to the results, the CT method can be recommended as a reference for determining the lean meat content of pig carcasses.     

Pregnancy stage and number of fetuses may influence maternal plasma leptin in ewes

Maternal plasma leptin is elevated in ewes during pregnancy. The authors studied whether there was any relation between maternal plasma leptin and insulin concentrations, the number of fetuses and the circulating and faecal levels of gestagens. At the end of the breeding season in January the ovarian activity of Prolific Merino ewes was induced/synchronised with gestagen + eCG treatment. Ewes were inseminated artificially (AI) by laparoscopy. Blood and faecal samples were collected before AI (day 0) and again 41, 81 and 101 days later. The plasma levels of leptin (pL), insulin and progesterone (pP4), and the faecal P4 metabolite (P4-met) content were determined. The day 0 level of pL was significantly higher in pregnant (n = 24) than in non-pregnant ewes (n = 32). By day 41 the pL of pregnant animals had doubled, it showed a further moderate increase on day 81, and decreased slightly thereafter. During pregnancy pP4 and faecal P4-met rose continuously and were positively correlated at all stages. The mean levels of pL and pP4 and the faecal content of P4-met were lower in ewes bearing single (n = 12) than in those with 2 (n = 6) or 3-5 fetuses (n = 6). Analysis of variance demonstrated significant differences according to the number of fetuses in the pL and pP4, but not in P4-met (p = 0.042, 0.044, and 0.051, respectively). Leptin showed positive correlation with insulin before the AI but not during pregnancy. On days 41 and 81 pL showed a slight positive correlation with P4 and P4-met, which decreased slightly by day 101. This study shows that although leptinaemia is affected by the number of fetuses and the level of P4, pregnancy stage is a more important regulator than these additional factors.     

Detection and molecular characterization of Suid herpesvirus type 1 in Austrian wild boar and hunting dogs

Aujeszky's disease (AD), caused by Suid herpesvirus type 1 (SuHV-1), is an economically important disease in domestic swine. Thus, rigorous control programmes have been implemented and consecutively AD in domestic swine was successfully eradicated in many countries, including Austria. However, SuHV-1 continues to thrive in wild boar populations, as indicated by high seroprevalences in a number of European countries and by occasional cases of AD in hunting dogs. For the first time, SuHV-1 was detected in Austrian wild boar and a molecular characterization of SuHV-1 isolated from wild boar and hunting dogs was performed. Results of preliminary serological analyses suggest a regional SuHV-1 seroprevalence of over 30% in free-living and almost 70% in fenced wild boar from Eastern Austria. Molecular typing of Austrian SuHV-1 isolates of wild boar origin revealed the presence of two genetically distinct variants of SuHV-1, both capable of infecting dogs that have been exposed to infected wild boar during hunting.     

The identification of a VDAC-like protein involved in the interaction of Babesia bigemina sexual stages with Rhipicephalus microplus midgut cells

Oestrosis is highly prevalent in Mediterranean countries. Understanding the life cycle of Oestrus ovis is crucial to design effective control measures of this myiasis, largely based on the use of macrocyclic lactones. We carried out a survey of ovine oestrosis in the island of Majorca (Spain) and found that 46.03% of animals were infested in a 13-month period. Interestingly, we found significant differences in oestrosis prevalences in winter and autumn when separating the animals by group of age (P<0.001). Pearson correlation analysis showed that prevalence in lambs younger than 4 months was significantly affected by changes in air temperature (P<0.05), but this association was not significant in adult sheep (P=0.081). Chronic infestations or unsystematic treatments may explain confusing results in adult sheep. Observing the evolution of the disease in young lambs, we determined that the hypobiotic period took place from October to February and the beginning of fly activity occurred between May and June. Interannual variations in oestrosis prevalence indicate the need of monitoring the disease to establish the appropriate timing of treatments. We hypothesize that lambs are better indicators of the seasonality of oestrosis than their older counterparts. Furthermore, we propose that observing O. ovis infestations in young lambs can be used as an efficient early warning system of fly activity, to be applied in future control programs.     

Effect of area decrease in a food competition situation in captive wild boars (Sus scrofa)

The aim of the present study was to examine the effect of area reduction on the hierarchy-dependent behaviors of wild boars and crossbred sows (wild boar × Vietnamese pot-bellied pig) living in captivity, with regard to a food competition situation. We first defined the hierarchy system among 7 individuals, living together for more than a year, with a mathematical model based on wins and defeats. We then tested the possibility of a correspondence between the rank position and the age and/or weight. In a first experiment, we defined the frequency of dominant and submissive behavioral elements depending on the rank and on the group level in a food competition situation. We analyzed individually the time spent feeding. In a second experiment, we reduced the size of their living area and observed the potential modifications of the dominant and submissive elements’ frequency as well as the time spent feeding.We found a linear hierarchy among the sows. We did not find any relationship between the rank and the age or the rank and the weight of the animals. However, after excluding the youngest and the lightest leader from the analysis, significant correspondence was found among the aforementioned variables. In such cases, the older and heavier sows occupied the higher ranks in the hierarchy. We also observed that the sow with the higher rank position spent more time feeding and presenting aggressive behaviors compared with the other individuals, whereas the sow with the lowest rank position spent the most time displaying submissive behavior. Moreover, the frequency of dominant and submissive behavioral elements increased when reducing the size of the living area.Based on our results, we found that the area reduction and, therefore, the higher density increased the frequency of aggressive and submissive behavioral elements of the sows.     

Non Cat-Like Ovarian Cycle in the Eurasian and the Iberian Lynx – Ultrasonographical and Endocrinological Analysis

The Iberian lynx is considered the most endangered felid species. Therefore, an ex situ conservation program was initiated to protect this species from extinction. Additional knowledge on lynx reproduction biology and reliable methods for reproductive monitoring are important for developing a captive breeding program. The aim of this study in lynx was to implement transrectal ultrasonography to visualize ovarian structures (follicles, corpora lutea) and to assess ovarian activity in addition to analysis of serum progesterone and oestradiol. Because of limited access to Iberian lynxes, the less-endangered Eurasian lynx and bobcat were also studied in this comparative study. Recent endocrinological studies based on faecal and urinary progesterone and oestrogen metabolites revealed that steroid profiles in both these species were alike and did not follow the typical pattern of other felids. Pregnancy diagnosis was not possible, since progesterone concentrations did not differ between pregnant and pseudopregnant animals. Progesterone was also detected after parturition as well as after weaning until the onset of a new oestrous cycle. In the present study, the presence of corpora lutea during the non-breeding season was confirmed by ultrasonography and by elevated serum levels of progesterone averaging 3.56 ± 1.3 ng/ml in Eurasian and 6.1 ± 0.26 ng/ml in Iberian lynx, respectively. The ultrasonographical findings on the ovarian structures suggest strongly that corpora lutea developed after ovulation stay active until November and regress before the onset of the next oestrus.