Genetic diversity of Swiss sheep breeds in the focus of conservation research

There is constant pressure to improve evaluation of animal genetic resources in order to prevent their erosion. Maintaining the integrity of livestock species as well as their genetic diversity is of paramount interest for long-term agricultural policies. One major use of DNA techniques in conservation is to reveal genetic diversity within and between populations. Forty-one microsatellites were analysed to assess genetic diversity in nine Swiss sheep breeds and to measure the loss of the overall diversity when one breed would become extinct. The expected heterozygosities varied from 0.65 to 0.74 and 10.8% of the total genetic diversity can be explained by the variation among breeds. Based on the proportion of shared alleles, each of the nine breeds were clearly defined in their own cluster in the neighbour-joining tree describing the relationships among the breeds. Bayesian clustering methods assign individuals to groups based on their genetic similarity and infer the number of populations. In STRUCTURE, this approach pooled the Valais Blacknose and the Valais Red. With BAPS method the two Valais sheep breeds could be separated. Caballero & Toro approach (2002) was used to calculate the loss or gain of genetic diversity when each of the breeds would be removed from the set. The changes in diversity based on between-breed variation ranged from -12.2% (Valais Blacknose) to 0% (Swiss Black Brown Mountain and Mirror Sheep); based on within-breed diversity the removal of a breed could also produce an increase in diversity (-0.6% to + 0.6%). Allelic richness ranged from 4.9 (Valais Red) to 6.7 (Brown Headed Meat sheep and Red Engadine Sheep). Breed conservation decisions cannot be limited to genetic diversity alone. In Switzerland, conservation goals are embedded in the desire to carry the cultural legacy over to future generations.

[Livestock owners with specifically increased disease awareness for Bluetongue: A new approach to disease surveillance]

For the first time in Switzerland, specifically trained livestock owners were included in a national disease surveillance program by the Federal Veterinary Office. A questionnaire on data about clinical and epidemiological aspects of Bluetongue Disease (BT) as well as on herd management was completed by 26 sheep owners three months after they had attended a training course about BT. The control group, consisted of 264 randomly selected sheep and cattle owners who had not visited a training course. Results showed that disease awareness for BT after attending the training course was considerably increased. This was especially evident in the better knowledge of the participants about the great number of possible symptoms. Training courses with the objective of increased disease awareness of livestock owners are an efficient, cost-effective instrument in control programs for exotic diseases.

Effects of group stability on aggression, stress and injuries in breeding rabbits

On Swiss rabbit breeding farms, group-housed does are usually kept singly for 12 days around parturition to avoid pseudograviclity, double litters and deleterious fighting for nests. After this isolation phase there is usually an integration of new group members. Here we studied whether keeping the group composition stable would reduce agonistic interactions, stress levels and injuries when regrouping after the isolation phase. Does were kept in 12 pens containing 8 rabbits each. In two trials, with a total of 24 groups, the group composition before and after the 12 days isolation period remained the same (treatment: stable, S) in 12 groups. In the other 12 groups two or three does were replaced after the isolation phase by unfamiliar does (treatment: mixed, M). Does of S-groups had been housed together for one reproduction cycle. One day before and on days 2, 4 and 6 after regrouping, data on lesions, stress levels (faecal corticosterone metabolites, FCM) and agonistic interactions were collected and statistically analysed using mixed effects models. Lesion scores and the frequency of agonistic interactions were highest on day 2 after regrouping and thereafter decrease in both groups. There was a trend towards more lesions in M-groups compared to S-groups. After regrouping FCM levels were increased in M-groups, but not in S-groups. Furthermore, there was a significant interaction of treatment and experimental day on agonistic interactions. Thus, the frequency of biting and boxing increased more in M-groups than in S-groups. These findings indicate that group stability had an effect on agonistic interactions, stress and lesions. (C) 2012 Elsevier B.V. All rights reserved.

Bovine viral diarrhea virus in free-ranging wild ruminants in Switzerland: low prevalence of infection despite regular interactions with domestic livestock

ABSTRACT: BACKGROUND: In the frame of an eradication program for bovine viral diarrhea (BVD) in Swiss livestock, the question was raised whether free-ranging wildlife could threaten the success of this sanitary measure. Therefore, we conducted serological and virological investigations on BVD virus (BVDV) infections in the four indigenous wild ruminant species (roe deer, red deer, Alpine chamois and Alpine ibex) from 2009 to 2011, and gathered information on interactions between wild and domestic ruminants in an alpine environment by questionnaire survey. RESULTS: Thirty-two sera out of 1'877 (1.7%, 95% confidence interval [CI] 1.2-2.4) were seropositive for BVDV, and a BVDV1 sub genotype h virus was found in a seropositive chamois (0.05%, 95% CI 0.001-0.3). The seropositive animals originated from sub-alpine or alpine regions and significantly more seropositive red deer, chamois and ibex than roe deer were found. There were no statistically significant differences between sampling units, age classes, genders, and sampling years. The obtained prevalences were significantly lower than those documented in livestock, and most positive wild ruminants were found in proximity of domestic outbreaks. Additionally, BVDV seroprevalence in ibex was significantly lower than previously reported from Switzerland. The survey on interspecific interactions revealed that interactions expected to allow BVDV transmission, from physical contacts to non-simultaneous use of the same areas, regularly occur on pastures among all investigated ruminant species. Interactions involving cervids were more often observed with cattle than with small ruminants, chamois were observed with all three domestic species, and ibex interacted mostly with small ruminants. Interactions related to the use of anthropogenic food sources were frequently observed, especially between red deer and cattle in wintertime. CONCLUSIONS: To our knowledge, this is the first report of BVDV RNA isolated from an Alpine chamois. Nevertheless, our results suggest that BVDV infections are only sporadic in Swiss wild ruminants, despite regular occurrence of interactions with potentially infected livestock. Overall, serological, virological and ethological data indicate that wildlife is currently an incidental spill-over host and not a reservoir for BVDV in Switzerland.

Antimicrobial resistance in Escherichia coli strains isolated from Swiss weaned pigs and sows

Based on Directive (EC) No 99/2003, monitoring programs on the development of antimicrobial resistance in bacteria from livestock are implemented in many European countries. The aim of the present study was (i) to establish comprehensive baseline data on the antimicrobial resistance situation in Escherichia coli isolates obtained from healthy pigs (pooled fecal samples) originating from 60 Swiss pig-breeding farms, and (ii) to analyze differences in the resistance frequency between Escherichia coli isolates from weaned pigs and sows. Susceptibility testing (disc diffusion method) was performed on 429 isolates from weaned pigs and 431 isolates from sows. Overall, 17.7% of the isolates from weaned pigs and 22.5% of the Escherichia coli isolates from sows were susceptible to all antibiotics tested. Low resistance prevalence was found for amoxicillin, amoxicillin/clavulanic acid, ampicillin, cefquinome, ciprofloxacin, colistin, florfenicol, and gentamicin. The most frequently found resistances were against streptomycin (60.6% of the isolates from weaners and 64.3% of the isolates from sows), sulfonamide (51.5% and 26.9%), tetracycline (35.2% and 22.0%), and trimethoprim (27.5% and 11.1%). With exception of colistin, most resistances were found for those antibiotics commonly used on the farms. Except for ciprofloxacin and streptomycin, isolates from weaned pigs showed higher resistance prevalence than those from sows. This difference was significant for cefquinome, florfenicol, sulfonamide, tetracycline, and trimethoprim (p<0.05).