Bovine tuberculosis and milk production in infected dairy herds in Ireland

This study describes the relationship between bovine tuberculosis (TB) and milk yield in TB-infected dairy herds in Ireland. The study had two objectives: to determine whether cows detected as TB reactors (and thus subject to immediate slaughter) were likely to be the higher milk-producing cows, and to determine whether subclinical TB infection was associated with reduced milk production at or around the time of disclosure (detection). All Irish dairy herds restricted from trading between the 1^st June 2004 and the 31^st May 2005 as a result of two or more TB reactors by the Single Intradermal Comparative Tuberculin Test (SICTT) were considered for study. The data consisted of 419 herds. Data were collected on all TB reactors and a random sample of 5 non-reactor cows in these herds: a data set of 4340 cows (2342 TB reactors and 1998 non-reactors). Previous milk data for the cows were taken into consideration and thus all lactations on a cow were analysed together with the years of lactations. There was an inherent hierarchical structure in the data, with lactations nested within cows and cows within herds and thus a linear mixed model with two random effects was used to describe the data. The results of this study showed that for all lactations and years under investigation, milk yield was significantly lower for TB reactor cows, with differences ranging from 120 kg (2003, lactation 3) to 573 kg (2001, lactation 1), when compared to the non-reactor cows.     

Quantitative trait loci for early maturity and their potential in breeding for earliness in Brassica juncea

A doubled haploid population of Brassica juncea, developed from a cross between two parental lines differing for days to maturity, was used to study the efficiency of indirect selection for a primary trait through selection of secondary trait(s) over direct selection for the primary trait when quantitative trait loci information is available for both primary and secondary traits, and applied. Days to maturity was considered as primary trait, while days to first flowering, days to end of flowering, flowering period and plant height were considered as secondary traits. An RFLP linkage map was employed for QTL analysis of maturity and maturity-determinant traits, and a stable QTL B6 simultaneously affecting these two types of traits was identified. This linked QTL explained 11.7% phenotypic variation for days to maturity, 20.7% variation for days to first flowering, 24.3% variation for days to end of flowering and 14.4% variation for plant height. Phenotypic evaluation of maturity and/or maturity-determinant traits, viz. days to first flowering, days to end of flowering and plant height revealed that limited genetic advance for early maturity can be achieved through phenotypic selection of the primary and/or the secondary trait(s). However, the estimates of genetic advance for early maturity based on combined phenotypic evaluation and linked QTL data was found to be, at least, three times higher compared to genetic advance based on phenotypic evaluation only, demonstrating the potential of marker-assisted selection in breeding for early maturity in B. juncea.     

Estimating tree component biomass using variable probability sampling methods

As a signatory to the Kyoto Protocol, Australia is obliged to stabilize greenhouse gas emissions at 8% above 1990 levels by 2008–2012. To demonstrate achievement of this goal, Australia requires national annual estimates of changes in vegetation biomass as greenhouse gas emissions from land use change. These emission estimates are, however, uncertain due largely to the scarcity of existing allometric equations for calculating biomass. The large investment of time and funding required for harvesting, particularly using traditional techniques such as double regression and ratio sampling, also precludes the generation of new equations. Alternative techniques for rapid, cost-effective, and reliable estimation of biomass therefore require investigation. This study, conducted in central Queensland, compared estimates of component biomass that were generated for seven trees of the woodland species Eucalyptus populnea (poplar box) using ratio sampling and variable probability sampling techniques, namely randomized branch sampling (RBS) and RBS with importance sampling (IS). Application of randomized branch sampling consistently underestimated the biomass of leaf and small branches (<1 cm in diameter) and produced weak prediction equations. In contrast, results suggest that RBS with IS is particularly useful in predicting woody (trunk and branches >1 cm in diameter) biomass, and prediction equations agreed with existing equations for this species. However, this method tended to overestimate individual tree woody biomass. The study concluded that RBS with IS was a viable alternative to current methods.     

A primary extraskeletal osteogenic sarcoma arising in the spleen of a dog

This paper describes a primary extraskeletal osteogenic sarcoma arising in the spleen of an 11-year-old, male, cross-bred Terrier. Initial diagnosis was made after surgical removal of a splenic mass, at which time the liver and other abdominal viscera appeared grossly normal. However, elevations in the activities of alanine aminotransferase and alkaline phosphatase in blood taken 7 days after laparotomy suggested that hepatic metastases were developing. This was confirmed when the dog died 3.5 months after surgery, with massive hepatic metastatic involvement. There appears to be no previous report of the spleen being the primary site of such a neoplasm in the dog.     

First report of a mecA-positive multidrug-resistant Staphylococcus pseudintermedius isolated from a dog in New Zealand

CASE HISTORY: A 14-year-old neutered male Sealyham terrier was referred for assessment of a persistent pyoderma. It had experienced numerous episodes of dermatitis involving pododermatitis, pyoderma and otitis over the previous 6 years.

CLINICAL FINDINGS: Superficial, focally deep and mucocutaneous pyoderma were present, with yellow mucoid exudate on both nares and the lower lips crusted with haemopurulent exudate. Epidermal collarettes were present on the dorsal and lateral trunk. There were peri-anal crusts and mild erythema was present on the concave aspect of both pinnae.

MICROBIOLOGICAL FINDINGS: Culture and microbiological testing identified Staphylococcus pseudintermedius as the infecting organism. Kirby-Bauer disc susceptibility testing revealed the isolate was resistant to numerous antimicrobials including oxacillin. PCR testing of the isolate identified the presence of the mecA gene which confers resistance to β-lactam antimicrobials. Pulsed field gel electrophoresis typing suggested the isolate was not related to the methicillin-resistant S. pseudintermedius that had been reported to be associated with canine infections in Western Australia.

DIAGNOSIS: Superficial, deep and mucus membrane pyoderma associated with a multi-drug resistant S. pseudintermedius.

CLINICAL RELEVANCE: This is the first recorded case of canine pyoderma involving methicillin-resistant multidrug-resistant S. pseudintermedius in New Zealand. Treatment of such cases is difficult because the number of effective and available antimicrobials is limited. This finding should raise the awareness of the veterinary and medical professions to the presence of such organisms in New Zealand and stimulate a discussion about possible biosecurity barriers, treatment strategies and prevention of zoonotic and nosocomial infections.     

Texel sheep are more resistant to natural nematode challenge than Suffolk sheep based on faecal egg count and nematode burden

Limited information is available on differences between sheep breeds with respect to helminth resistance under temperate conditions. The present study was designed to confirm and extend preliminary findings on observed breed differences in resistance to naturally acquired gastrointestinal nematodes in Suffolk and Texel sheep. Three trials were carried out. In trial 1 (1999-2003) lambs co-grazed from birth were faecal sampled at various time points up to 17 weeks of age. Worm burden was assessed at 17 weeks of age from a minimum of six lambs per breed in each of the 3 years. In trial 2, faecal egg count (FEC) was determined on six farms with co-grazed Suffolk and Texel purebred lambs. In trial 3 (2001-2003), ewes were faecal sampled at winter housing. In all three trials, an influence of breed on resistance to naturally acquired trichostrongyle infection was demonstrated. In trial 1, significantly higher FEC and worm burden was observed in Suffolk compared with Texel lambs following natural challenge. In trial 2, FEC recorded in lambs from six farms confirmed the breed differences previously observed. A breed difference in resistance to GI parasites was also observed in older ewes. In both breeds, an age effect on the FEC was observed with younger ewes having greater FEC than older ewes.     

Effects of diazepam, ketamine, and their combination on intraocular pressure in normal dogs

Ketamine has been implicated as causing increases in intraocular pressure. The purpose of this study is to document the effects of ketamine, diazepam, and their combination on intraocular pressure (IOP) in normal, unpremedicated dogs. Random-source dogs were assigned to one of five groups of 10 dogs each: ketamine 5 mg kg^–1 (KET5), ketamine 10 mg kg^–1 (KET10), diazepam 0.5 mg kg^–1 (VAL), ketamine 10 mg kg^–1 with diazepam 0.5 mg kg^–1 (KETVAL), saline 0.1 mL kg^–1 (SAL), all given intravenously. A baseline IOP was measured before injection, immediately after injection, and at 5, 10, 15, and 20 minutes following injection. IOP was increased over baseline immediately after injection in the KET5, KET10, and KETVAL groups; at 5, 10, and 15 minutes in the KET5 group; and at 20 minutes in the KETVAL group. The mean IOP change compared to SAL increased immediately after injection and at 5 minutes in the KET5, KET10, and KETVAL groups; at 10 and 15 minutes in the KET5 group, and at 20 minutes in the KETVAL group. The mean IOP increased up to 5.7, 3.2, and 3.1 mm Hg over mean baseline in the KET5, KET10, and KETVAL groups, respectively. All dogs in the KET5 group and the majority in the KETVAL and KET10 groups had an increase in their IOP over baseline. Ketamine caused a clinically and statistically significant elevation in IOP over baseline and compared to SAL. The concurrent addition of diazepam did not blunt this increase. Ketamine should be avoided in dogs with corneal trauma, glaucoma, or in those undergoing intraocular surgery.     

The clinical biochemistry of experimentally produced lupinosis in the sheep

Lupinosis was produced in sheep in four experiments by administering a toxic extract of Phomopsis leptostromiformis by various routes and at various dose rates. The course of the intoxication was followed by plasma biochemical analyses for a number of electrolytes, metabolites and enzymes. Results from these analyses suggested that in addition to being an hepatotoxicity, lupinosis also resulted in injury to muscle, kidney and adrenal cortex. This was confirmed by microscopic examination of these tissues.     

Rearing unit-level factors associated with bacterial gill disease treatment in two Ontario, Canada government salmonid hatcheries

Early-rearing salmonids in Ontario Ministry of Natural Resources (OMNR) fish hatcheries have been consistently affected by bacterial gill disease (BGD) (causative agent: Flavobacterium branchiophilum) for many years. Separate retrospective epidemiological investigations of BGD treatments at two OMNR fish hatcheries (Hatcheries A and B) for the 1999 production year were conducted using on-site hatchery records. Both investigations were carried out at the rearing unit-level, with early-rearing (<9 months of age) “tank-lot” as the unit of analysis to identify unique fish populations over time. Multivariable repeated measures logistic regression models were created for both hatchery datasets, controlling for lot-level and species effects. For Hatchery A, the species brook trout (Salvelinus fontinalis) and brown trout (Salmo trutta) were significantly associated with BGD treatment, as well as lower water exchange rate, and higher feeding and mortality percentages during the 2 weeks previous to BGD treatment. At Hatchery B, the species brook trout (S. fontinalis) and splake (Salvelinus namaycush × S. fontinalis) were significantly associated with BGD treatment, as well as lower individual fish weights and treatment for BGD during the previous week. These results emphasize the importance of water quality, feeding rate, fish size and prior mortality on the development of BGD. Significant hatchery and species effects were evident, and future observational research on BGD must account for these factors in their design and analysis.