Modifying otter boards to reduce bottom contact: effects on catches and efficiencies of triple‐rigged penaeid trawls

Two otter‐board modifications designed to minimise bottom contact (and therefore habitat impacts) were compared against conventional otter boards for their relative effects on the engineering and catching efficiencies of triple‐rigged penaeid trawls. The first modification involved restricting the angle of attack (AOA) of a flat–rectangular otter board to <30^° by attaching a restraining line to an adjacent sled, while the second was a ‘batwing’ otter board comprising a sled‐and‐sail assembly operating at 20^° AOA. The modifications reduced otter‐board bottom contact by up to 8 ha over a night's fishing without affecting standardised catches (per ha) of the targeted eastern king prawns, Penaeus plebejus, nor the fuel required. Further, compared to all other trawls, the restrained trawls caught less discarded bycatch (by up to 37%), while the trawls spread by the modified flat–rectangular and batwing otter boards caught more individuals of three retained benthic teleost species per ha than the conventional configuration; results that were attributed to species‐specific herding responses. Both modifications represent simple alternatives where there are concerns over either benthic impacts or, for the restraining line, unwanted bycatches in penaeid‐trawl fisheries.     

Novel employment of lactate dehydrogenase release from porcine aortic endothelial cells (PAEC) as a quantitative marker of cytotoxic activity in thermophilic Campylobacter spp. from human faecal isolates, poultry and environmental sources

The aim of this study was to employ a novel cytotoxicity assay based on primary porcine aortic endothelial cells in combination with a lactate dehydrogenase release assay to quantitatively determine differences in cytotoxin production between Campylobacter jejuni, C. coli, C. lari and urease-positive thermophilic campylobacters (UPTC), isolated from human faeces, animals and environmental sources. Campylobacter isolates totalling 34 and comprising of C. jejuni (n = 24) C. coli (n = 5) and UPTC (n = 4) and C. lari (n = 1) were analysed. The cytotoxic response ranged from 32.15 to 64.47% and 33.08 to 59.41%, for C. jejuni from chicken and human isolates, respectively and there was no statistically significant difference (P > 0.05) in cytotoxic response between C. jejuni isolated from humans and chicken isolates (50.78% versus 50.55% cytotoxicity, respectively). However, there was a difference in response between C. jejuni and C. coli isolated from chickens (50.78% versus 33.22% cytotoxicity, respectively). The greatest cytotoxic response was obtained with the UPTC group of organisms examined (n = 4 isolates) (mean cytotoxic response = 57.11% cytotoxicity. Employment of this cytotoxin assay may help identify virulent strains in poultry that could potentially proceed to cause clinical problems for humans and thus intervention measures targeted at the reduction or elimination of such specific strains, may be sought.     

Autosomic 27 Trisomy in a Standardbred Colt

A 19-month-old Standardbred colt was donated to the University of Pennsylvania School of Veterinary Medicine with a suspicion of intersexuality. The anal−genital distance and penis were normal, and there was no evidence of intersexuality, but the colt was bilaterally cryptorchid. Several aspects of the colt's behavior appeared unusual, including general temperament and behavior described as sympathetically dull and affable. With herd mates, the colt appeared slow to perceive or to learn the usual intraspecies social cues. An atypical gait characterized by intermittent unnatural shuffle of the hind limbs, sliding them along in short rhythmic strides for 3 to 10 seconds at a time was noted at times when a horse might normally transition from a slow walk to a fast walk or a slow trot. Occasionally the colt exhibited slight protrusion of the tongue through the teeth and lips with jaw movements and smacking of the tongue against the teeth as if struggling to retract the tongue to the normal position. Evaluation of the karyotype combined with fluorescent in situ hybridization (FISH) revealed an abnormal male karyotype showing trisomy of chromosome 27 (65, XY + 27). The colt was euthanized at 24 months of age, and a necropsy revealed no significant abnormalities. This case of trisomy was not associated with developmental abnormalities described in other rare reports of trisomy in horses; however, some features were strikingly similar to that of humans with trisomy 21. FISH was demonstrated to be an excellent method for correct identification of equine chromosomes.     

Challenging the boundaries of local and scientific knowledge in Australia: Opportunities for social learning in managing temperate upland pastures

Evidence of an emerging focus on the role of farmer knowledge in developed countries is highlighted by the debate on the nature of local and scientific knowledge. Less attention has been paid to the interaction of different ways of knowing for sustainable capital-intensive agriculture. This paper explores the relationship between local and scientific knowledge in managing temperate pasture and grazing systems in Australia. The nature of farmer knowledge is firstly examined by describing the experiences of farm families in managing native and introduced perennial grasses in upland areas of the Murray-Darling Basin. The building of knowledge and skills through social learning was explored in group case studies and interviews with stakeholders involved in pasture research and development. The interchange of local and scientific knowledge in groups was shown to have a synergistic effect, whereby local knowledge was broadened and strengthened, and scientific knowledge adapted and molded to specific situations. The effectiveness of social learning was greatest in collaborative programs based on small, local groups involved in monitoring and evaluation of whole farm pasture and grazing systems.     

Cumulative selectivity benefits of increasing mesh size and using escape gaps in Australian Portunus armatus traps

The individual and cumulative effects of increasing mesh size (from 56‐ to 75‐mm stretched mesh opening) and installing three escape gaps (36 × 120 mm) in collapsible‐netted round traps were assessed to address concerns associated with excessive discarding in an Australian portunid fishery. Compared to conventional traps comprising 56‐mm mesh throughout, those with the same mesh size and escape gaps caught significantly fewer (by 54%) undersized blue swimmer crabs, Portunus armatus Milne‐Edwards and yellowfin bream, Acanthopagrus australis Günther (by 64%). Irrespective of escape gaps, simply increasing the mesh size to 75 mm did not significantly affect catches of undersized P. armatus, although 87% fewer A. australis were retained. Traps with both 75‐mm mesh and escape gaps maintained reductions of A. australis, but had a clear cumulative effect on P. armatus selection, retaining 84% fewer undersized individuals across a larger size at retention. The results support using escape gaps in existing conventional traps, but illustrate the need to configure the minimum legal mesh size to approach the desired target size of P. armatus as a precursor to maximising trap selectivity. Larger‐meshed traps also require less material (i.e. plastic), which benefits their manufacture and, equally importantly, reduces environmental costs when lost.     

Spatial and temporal distribution of Lepeophtheirus salmonis (Kr?yer) larvae in a sea loch containing Atlantic salmon, Salmo salar L., farms on the north-west coast of Scotland.

A plankton survey investigated spatial and temporal distributions of larval sea lice in a sea loch on the north-west coast of Scotland. Plankton tows were collected approximately weekly at two depths (0 and 5 m) at five sample stations over a 2-year period. The survey began in March 2002 when Atlantic salmon, Salmo salar L., farms in the study area stocked with fish and finished in March 2004, after farms completed harvesting. Over 90% of lice recovered were Lepeophtheirus salmonis (Kr?yer); therefore, the results of this paper refer largely to that species. The data were analysed using generalized additive models with explanatory variables for time, depth and station. Greatest densities of nauplii were recovered at stations adjacent to farms indicating that the local salmon farms were a likely source of larvae at times during the production cycle. There were significant temporal trends in larval densities and the stocking and harvesting of farms can possibly account for these increases and decreases, particularly at the start and at the end of the production cycle. The distribution of copepodids was more widespread than that of nauplii, indicating that the larvae can be transported several kilometres from the point of release.     

Prevalence of Multi-Drug-Resistant Salmonella in Equids Maintained by Low Income Individuals and on Designated Equine Farms in India

We examined 872 equids (445 maintained by low-income individuals and 427 maintained on nine designated equine farms) and, using previously described methods for bacteria, isolated Salmonella from fecal samples of 59 (6.77%) animals. Of the 646 horses, 183 donkeys, and 43 mules that had feces cultured for Salmonella, 42 (6.5%), 7 (3.8%), and 10 (23.3%), respectively, were excreting Salmonella strains in feces. Six horse mares were excreting Salmonella enterica of two different serovars simultaneously. A total of 65 Salmonella enterica isolates belonged to 13 serovars, namely S. paratyphi B var Java (14), S. I. 4, 5, 12, 27: r, i: 1, 5 (11), S. Drogana (8), S. Newport (7), S. Saintpaul (5), S. Lagos (4), S. Typhimurium (5), S. Kottbus (3), S. Bovismorbificans (3), S. Dumfries (2), S. Tshiongwe (1) S. Weltevreden (monophasic) (1), and S. enterica ssp salamae (1). With Salmonella-specific polymerase chain reaction (PCR) using hisJ gene primers, 107 (12.3) fecal samples yielded a specific amplicon of 496 bp. On using PCR, prevalence of Salmonella in donkeys, horses, and mules was 4.9%, 10.8%, and 65.1%, respectively. With both methods of Salmonella detection in feces, prevalence was significantly higher in female than in male donkeys and horses. Salmonella shedding in feces was significantly higher in equids maintained by low-income people than those at designated equine farms. Almost all Salmonella isolates (63 of 65) had multiple-drug-resistance (MDR, resistance to three or more drugs). Salmonella isolates were commonly resistant to sulfamethoxazole (90.8%), tetracycline (70.8%), doxycycline (67.7%), furazolidone (66.2%), and colistin (55.4%). A few isolates had resistance to trimethoprim (3.1%), ciprofloxacin (3.1%), ceftriaxone (3.1%), ceftazidime (3.1%), cefoperazone (3.1%), chloramphenicol (4.6%), cefotaxime (6.2%), gentamicin (9.2%), ampicillin + cloxacillin (9.2%), cotrimoxazole (13.8%), kanamycin (13.8%), amoxicillin + clavulanic acid (16.9%), imipenem (16.9%), ampicillin (18.5%), amikacin (23.1%), neomycin (27.7%), nalidixic acid (33.8%), and streptomycin (36.9%). With the exception of 13 Salmonella isolates of S. Drogana (4), S. Newport (4), S. I. 4, 5, 12, 27: r, i: 1, 5 (4) and S. Kottbus (1) serovars, all had one or more than one plasmid. Molecular weight of plasmids ranged between 3 kDa and >87 kDa. One heavy plasmid (≥87 kda) was present in all the 52 plasmid-positive strains. Presence of plasmid could not be correlated with MDR in Salmonella isolates from equids.     

Fertility Results of Artificial Inseminations Performed with Liquid Boar Semen Stored in X-CellTM vs BTS Extender

The objective of the present field study was to compare the fertility results for boar semen diluted in X-cell stored up to 4-5 days before artificial insemination (AI) with semen diluted in Beltsville thawing solution (BTS) used for AI following 2-3 days of storage (where the first day being the collection day). A total number of 2601 double inseminations in Norwegian herds were included in this two-trial study. All the boars used in the study were mature cross-bred Norwegian Landrace x Duroc (LD), which were routinely used for AI in Norway. The inseminated gilts and sows were Norwegian Landrace x Yorkshire (LY). The AI doses contained 2.5 billion spermatozoa, and consisted of a mixture of semen from three, occasionally four, boars (i.e. heterospermic semen). Fertility was measured in terms of the likelihood of farrowing and subsequent litter size. The fertility of the semen in both of the extenders was satisfactory and no significant differences were found either in semen stored 4-5 days in X-cell compared with 2-3 days in BTS or in semen stored 2-3 days in X-cell compared with 2-3 days in BTS. The storage capability findings for the long-term extender X-cell could significantly simplify the practical issues of semen production and the distribution of AI doses containing 2.5 billion spermatozoa. However, in pig production systems where all semen is used within 2-3 days, the short-term extender BTS is as good as the more expensive extender X-cell.