Veterinary Clinical Sciences - Research Publications
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ItemNo Preview AvailableMycobacterium avium ssp paratuberculosis High Shedding in an Adult Female Alpaca, and its Implications for the Rest of the Herd(WILEY-BLACKWELL PUBLISHING, INC, 2009)
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ItemMapping quantitative trait loci (QTL) in sheep. II. Meta-assembly and identification of novel QTL for milk production traits in sheep(BMC, 2009-10-22)An (Awassi x Merino) x Merino backcross family of 172 ewes was used to map quantitative trait loci (QTL) for different milk production traits on a framework map of 200 loci across all autosomes. From five previously proposed mathematical models describing lactation curves, the Wood model was considered the most appropriate due to its simplicity and its ability to determine ovine lactation curve characteristics. Derived milk traits for milk, fat, protein and lactose yield, as well as percentage composition and somatic cell score were used for single and two-QTL approaches using maximum likelihood estimation and regression analysis. A total of 15 significant (P < 0.01) and additional 25 suggestive (P < 0.05) QTL were detected across both single QTL methods and all traits. In preparation of a meta-analysis, all QTL results were compared with a meta-assembly of QTL for milk production traits in dairy ewes from various public domain sources and can be found on the ReproGen ovine gbrowser http://crcidp.vetsci.usyd.edu.au/cgi-bin/gbrowse/oaries_genome/. Many of the QTL for milk production traits have been reported on chromosomes 1, 3, 6, 16 and 20. Those on chromosomes 3 and 20 are in strong agreement with the results reported here. In addition, novel QTL were found on chromosomes 7, 8, 9, 14, 22 and 24. In a cross-species comparison, we extended the meta-assembly by comparing QTL regions of sheep and cattle, which provided strong evidence for synteny conservation of QTL regions for milk, fat, protein and somatic cell score data between cattle and sheep.
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ItemInfluence of allergen-specific immunotherapy on allergen-specific IgG subclasses in dogs with atopic dermatitis( 2008-03-03)Canine atopic dermatitis (AD) is one of the most common pruritic skin diseases in dogs and is diagnosed based on compatible history, clinical signs and exclusion of other pruritic skin diseases. Allergen-specific immunotherapy (ASIT) is widely used to treat AD but the precise mechanism of action is unknown. The aims of our study were to investigate the influence of ASIT on levels of Dermatophagoides farinae (D. farinae) specific IgG (D. farinae-IgG) subclasses and to explore whether changes in IgG subclasses are associated with the efficacy of ASIT. Sera from 98 dogs were collected before and during ASIT (duration of at least 2 years) with D. farinae. All dogs had serum IgE specific for D. farinae (imovet bg assay). Atopic dogs were divided into two groups: ASIT Group (n=48, ASIT as the sole therapy) and ASIT+ Group (n=50, insufficient control with ASIT requiring additional glucocorticoid treatment). A control group (CTRL Group, n=32) consisted of dogs without dermatological disease. Allergen-specific IgG subclass antibodies were detected by ELISA using monoclonal antibodies specific for canine IgG1 – IgG4. D. farinae-IgG1 and IgG4 were detected in >78% of all sera before ASIT while D. farinae-IgG2 and IgG3 were found in < 31%. Prior to therapy, dogs from the ASIT Group had significantly higher serum D. farinae-IgG1 than dogs in the ASIT+ Group (p<0.05). ASIT led to a significant increase in D. farinae-IgG1 in dogs from the ASIT (p<0.05) and ASIT+ (p<0.01) groups. D. farinae-IgG2, IgG3 and IgG4 concentrations were comparable for all groups before and during ASIT. Allergen-specific IgE concentration was not influenced by ASIT and the concentrations of IgG1 and IgG4 specific to an irrelevant antigen (Betula; birch pollen) were not influenced by ASIT against D. farinae. We conclude that long term ASIT increases levels of D. farinae-IgG1 and that dogs responding well to ASIT have a higher D. farinae-IgG1 concentration before therapy than partial responders.
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ItemBehavioral aspects of electronic bull separation and mate allocation in multiple-sire mating paddocks(AMER SOC ANIMAL SCIENCE, 2008-07)Controlling spatial positioning of cattle through use of electronic collars could provide new ways to farm under extensive conditions. This study examined the potential for bulls to be controlled during mating using mild electric shocks delivered through radio-controlled collars. Eighteen Belmont Red bulls were fitted with collars containing the Global Positioning System and that were able to emit a mild electric shock (500 mW) at the top of the neck behind the poll. Eighteen Belmont Red cows were fitted with Global Positioning System collars only. The experiment was replicated 3 times in 3 paddocks. Each paddock contained 2 bulls and 1 cow in induced estrus. On d 1, the bulls were either assigned to the cow or not assigned to the cow, and on d 2, the assignments were reversed, and bulls received the other treatment using a new cow. Treatments were applied for 2 h on each day. The nonassigned bull received a mild electric shock on approach to either the cow or to a bull, whereas the assigned bull received a mild electric shock on approach to the other bull only. The electric shock was applied when the bulls were within approximately 10 m and moving toward the nonallowed animal. The electric shock was terminated when the animal responded by stopping movement toward the nonallowed animal. In the first 10 min, nonassigned bulls spent less time within 5 m of the cow (P = 0.03) than assigned bulls. Assigned bulls spent more time close to the cow during the entire 120 min on d 1 than on d 2 (P = 0.014). On d 1, the assigned bulls moved more toward the cow and the nonassigned bull than they did on d 2 (P = 0.02). Assigned bulls displayed more sexual behaviors than nonassigned bulls (P = 0.004). Nonassigned bulls were sometimes observed not to approach the cow despite a change in its location. This suggests that the bull associated the electric shock with the cow and not with the location in which it received the electric shock. Instances were observed in which the cow pursued the nonassigned bull, in which case the bull did not receive an electric shock, and this may reflect the preference of the cow. This study demonstrated that bulls can be separated and prevented from approaching a cow in estrus using a mild electric shock. However, mate allocation was not completely successful due to the potential for cow preference for certain bulls.