Raphaël Vanderstichel - Academia.edu (original) (raw)

Papers by Raphaël Vanderstichel

Theriogenology, 2015

There is a growing interest in chemical sterilization as an alternative to surgical castration in... more There is a growing interest in chemical sterilization as an alternative to surgical castration in large-scale sterilization campaigns to control canine populations. An important step toward understanding the short-term and long-term effects of chemical sterilants is to determine their impact on blood testosterone concentrations, particularly as these could influence dog behavior after treatment. A field trial was conducted with 118 free-roaming male dogs in the Chilean Patagonia, where 36 dogs were chemically sterilized using EsterilSol, 39 dogs were surgically castrated, and 43 dogs remained intact as controls. Blood testosterone levels were determined at four time periods: on enrollment 6 months before treatment (t-6m), at the time of treatment (t0, within one hour after surgical castration or chemical sterilization and during a concurrent 2-week period for the control group), four (t+4m), and six (t+6m) months after treatment. Intrinsic and temporal factors were evaluated; age wa...

The Canadian veterinary journal. La revue vétérinaire canadienne, 2010

Trichomoniasis was diagnosed in multiple incidents of mortality in wild purple finch (Carpodacus ... more Trichomoniasis was diagnosed in multiple incidents of mortality in wild purple finch (Carpodacus purpureus) and American goldfinch (Carduelis tristis) in the Canadian Maritimes. Birds exhibited regurgitation, emaciation, and hyperplastic oropharyngitis, ingluvitis, and esophagitis. Trichomonas gallinae was identified by histopathology and polymerase chain reaction (PCR). Trichomoniasis (trichomonosis) is an emerging disease in wild finches of eastern Canada.

Veterinary Research, 2014

The Journal of general virology, Jan 15, 2015

Amphibian populations suffer massive mortalities from infection with Frog virus 3 (FV3, Ranavirus... more Amphibian populations suffer massive mortalities from infection with Frog virus 3 (FV3, Ranavirus, Iridoviridae), a pathogen also involved in mortalities of fish and reptiles. Experimental oral infection with FV3 in captive-raised adult wood frogs, Rana sylvatica [Lithobates sylvaticus], was performed as the first step in establishing a native North American animal model of ranaviral disease to study pathogenesis and host-response. Oral dosing was successful; LD50 was 10^2.93 (2.42-3.44) pfu for frogs averaging 35 mm in length. Onset of clinical signs occurred 6-14 days post-infection (dpi) (median 11 dpi) and time-to-death 10-14 dpi (median 12 dpi). Each ten-fold increase in virus dose increased the odds of dying by 23-fold and accelerated onset of clinical signs and death by approximately 15%. Ranavirus DNA was demonstrated in skin and liver of all frogs that died or were euthanized because of severe clinical signs. Shedding of virus occurred in feces (7-10 dpi; 3-4.5 d before dea...

Preventive veterinary medicine, 2012

Enzyme-linked immunosorbent assays (ELISAs) have been used as a diagnostic tool to quantify level... more Enzyme-linked immunosorbent assays (ELISAs) have been used as a diagnostic tool to quantify levels of gastrointestinal nematodes in dairy cattle by measuring Ostertagia ostertagi antibodies in milk. Higher levels of O. ostertagi antibodies measured by ELISA methods, referred to as optical density ratios (ODRs), are associated with decreased milk production in dairy cattle. On-farm management practices (e.g. pasturing techniques and anthelmintic usage) can influence the exposure of cattle to nematode infections and the magnitude of acquired worm burdens. Additionally, environmental and climatic factors, such as land elevation and precipitation, may also influence the levels of gastrointestinal parasitism. This repeated cross-sectional study investigated the effect of farm management practices and surrounding environmental factors on bulk tank (BT) ODRs in herds from provinces across Canada, and further examined the potential effects of various anthelmintic treatment protocols on BT O...

Veterinary Parasitology, 2010

The impact of various milk handling stressors were analyzed using a commercially available enzyme... more The impact of various milk handling stressors were analyzed using a commercially available enzyme-linked immunosorbent assay (ELISA) test measuring Ostertagia ostertagi antibodies in milk from dairy cattle (Svanovir). An indirect ELISA has the ability to determine the amount of milk production losses related to intestinal parasitism. The ELISA test recommends fresh defatted milk, however, milk collected from Dairy Herd Improvement (DHI) programs in North America undergo many stressors, including, heating, freezing and are not defatted. Normalized optical density ratios (ODRs) were compared between fresh defatted milk and milk subjected to one or more stressors with a linear mixed model accounting for differences in variation between the fresh and the frozen samples. Concordance correlation coefficients were also analyzed for comparisons to other similar studies. After accounting for random cow and container effects, the treatment factors interacted with each other (p<0.001). Biologically interesting contrasts were created to explain the interaction. The estimated difference in ODR between the milk samples handled according to recommendations of the manufacturers of Svanovir and the whole milk samples that were subjected to the most extreme treatment (heated, frozen, thawed, and re-frozen for 4 weeks) was 0.062 (p<0.001). This difference represented less than 5% of the range, and was thus considered biologically negligible. Frozen whole milk processed by DHI programs, the most likely method of collecting on-farm samples in North America, will likely yield reliable results for the indirect ELISA tests, particularly, Svanovir.

Preventive Veterinary Medicine, 2013

Freedom from infection modeling, using scenario trees, has become an established methodology and ... more Freedom from infection modeling, using scenario trees, has become an established methodology and is well described in the literature. However, standards for organizing and reporting the surveillance information incorporated into such models are less developed. Canada has been routinely testing for Trichinella spiralis in market hogs in federally inspected slaughter plants since the late 1990s. By way of presenting our work on T. spiralis in Canadian hogs, we propose that information in surveillance models be organized in distinct categories, each with specific parameters and values that are thoroughly described and justified. The proposed categories are: (1) definitions for the objectives, (2) initial time period, (3) inputs, (4) data, (5) model settings, (6) outputs, and (7) validation. Having a standardized manner of reporting such studies will facilitate their validation and expedite their evaluation by experts in the field and their use in trade negotiations.

Preventive Veterinary Medicine, 2015

Please cite this article in press as: Tenzin, T., et al., Comparison of mark-resight methods to e... more Please cite this article in press as: Tenzin, T., et al., Comparison of mark-resight methods to estimate abundance and rabies vaccination coverage of free-roaming dogs in two urban areas of south Bhutan. PREVET (2015), http://dx.Please cite this article in press as: Tenzin, T., et al., Comparison of mark-resight methods to estimate abundance and rabies vaccination coverage of free-roaming dogs in two urban areas of south Bhutan. PREVET (2015), http://dx.

Veterinary Pathology, 2013

Intratesticular injection of EsterilSol (zinc gluconate neutralized with arginine) is a chemical ... more Intratesticular injection of EsterilSol (zinc gluconate neutralized with arginine) is a chemical sterilant for male dogs sometimes used in population control campaigns. Adverse reactions have been reported in 1% to 4% of treated dogs, but detailed histomorphologic descriptions are lacking. During a behavioral study conducted in the Chilean Patagonia in 2012, severe necrosuppurative orchitis and ulcerative dermatitis were observed in 2 of 36 (6%) dogs sterilized with EsterilSol according to the manufacturer's instructions. Reactions were noted on days 8 and 7 postinjection and required scrotal ablation on days 8 and 13, respectively; neither reaction was associated with the injection site. Although self-trauma following administration may have contributed, the cause of the adverse reactions is uncertain. EsterilSol is a relatively uncomplicated method to sterilize male dogs, but the occurrence of severe adverse reactions several days after administration emphasizes the need for the provision of long-term monitoring and veterinary care during sterilization campaigns using this product.

Veterinary Pathology, 2013

Many subtypes of low-pathogenicity avian influenza (LPAI) virus circulate in wild bird reservoirs... more Many subtypes of low-pathogenicity avian influenza (LPAI) virus circulate in wild bird reservoirs, but their prevalence may vary among species. We aimed to compare by real-time reverse-transcriptase polymerase chain reaction, virus isolation, histology, and immunohistochemistry the distribution and pathogenicity of 2 such subtypes of markedly different origins in Mallard ducks (Anas platyrhynchos): H2N3 isolated from a Mallard duck and H13N6 isolated from a Ring-billed Gull (Larus delawarensis). Following intratracheal and intraesophageal inoculation, neither virus caused detectable clinical signs, although H2N3 virus infection was associated with a significantly decreased body weight gain during the period of virus shedding. Both viruses replicated in the lungs and air sacs until approximately day 3 after inoculation and were associated with a locally extensive interstitial, exudative, and proliferative pneumonia. Subtype H2N3, but not subtype H13N6, went on to infect the epithelia of the intestinal mucosa and cloacal bursa, where it replicated without causing lesions until approximately day 5 after inoculation. Larger quantities of subtype H2N3 virus were detected in cloacal swabs than in pharyngeal swabs. The possible clinical significance of LPAI virus-associated pulmonary lesions and intestinal tract infection in ducks deserves further evaluation.

Preventive Veterinary Medicine, 2010

The aim of this study was to explore whether anti-Ostertagia ostertagi antibody levels measured b... more The aim of this study was to explore whether anti-Ostertagia ostertagi antibody levels measured by ELISA in individual milk samples hold promise as a decision parameter for either herd-level decisions or selective anthelmintic treatments by investigating (1) the relationship between individual and bulk-tank milk ELISA results; (2) the relationships of individual milk ELISA results with non-parasitic cow factors and (3) the relationship between individual milk ELISA results and the milk production response after anthelmintic treatment. Twelve farms were randomly allocated to a whole-herd treatment with eprinomectin or a placebo in October 2004 and individual milk samples and a bulk-tank milk sample were collected 1 month before and 1 month after treatment. Linear mixed models were used to investigate the associations of ELISA results with (a) breed, actual milk production, lactation stage, somatic cell count, age and sampling month and (b) the milk production response after anthelmintic treatment. There was a reasonable correlation between the mean individual and bulk-tank milk ELISA results (r=0.72). Individual cow ELISA results increased with higher lactation number and were lower in November than September. The associations with the other non-parasitic factors were weak and not significant. Milk yield responses to anthelmintic treatment were greater when treatment was given in early lactation and increased with the pre-treatment ELISA result and cow age. However, these latter two interaction terms were not significant when they were put in the model together. We conclude that (1) O. ostertagi ELISA results from individual milk samples may provide more information on the herd's parasitic status than a single bulk-tank milk result; (2) lactation number should be taken into account when interpreting ELISA results from individual milk samples and (3) the value of the O. ostertagi antibody level in individual cow milk samples to predict individual production responses after anthelmintic treatment remains equivocal.

Preventive Veterinary Medicine, 2013

Gastrointestinal nematodes, such as Ostertagia ostertagi and several species of Cooperia, are ubi... more Gastrointestinal nematodes, such as Ostertagia ostertagi and several species of Cooperia, are ubiquitous in temperate climates and have been shown to have detrimental effects on production in adult dairy cattle. A published meta-analysis demonstrated that overall, producers lose approximately 0.35 kg of milk per parasitized cow per day. Enzyme-linked immunosorbent assays (ELISAs) have the ability to quantify nematode infections in cattle, and thus, could be used to estimate the amount of milk production loss due to differing levels of parasitism at the individual cow level. ELISA results from individual cow milk samples were used to predict milk production response following a randomized anthelmintic treatment in a large field trial. To increase statistical power, the data collected from this field trial was pooled with data from two other published field trials to form an individual patient data meta-analysis (IPDMA). The ability to predict the effect of anthelmintic treatment on milk production depends on the level of parasitism quantified by an ELISA measuring milk antibodies against O. ostertagi, and reported as optical density ratios (ODRs). Therefore, the estimates from the interaction between ODR and treatment on milk production were used to determine how well the ODR predicted the response of the treatment. It was anticipated that the relationship between milk production and ODR was unlikely to be linear, so fractional polynomials were applied to the continuous ODR values. The interaction in the field trial showed a trend (p=0.138) toward a beneficial treatment effect when the individual ODR values, measured in late lactation and using Svanovir(®), were greater than 0.12. When individual data from two other similar studies were included in an IPDMA, the interaction terms became statistically significant (p=0.009) indicating that there is a beneficial treatment effect when ODR values are slightly elevated. A graph was used to demonstrate the treatment effect (the estimated difference of kg/cow/day of milk yield between the treated and placebo cows), with 95% confidence intervals, as the ODR values increase. It is important to note that the methods of quantifying the ODR values differed between the three studies in the IPDMA, therefore some caution should be used when using these final estimated values. However, the shape and magnitude of the treatment effects, as well as the other fixed model estimates, were very similar between the field trial and the IPDMA suggesting that any bias would likely be minimal.

Journal of Wildlife Diseases, 2012

Collection of blood from amphibians, as in other classes of vertebrate animals, is essential to e... more Collection of blood from amphibians, as in other classes of vertebrate animals, is essential to evaluate parameters of health, diagnose hemoparasitism, identify viral and bacterial pathogens, and measure antibodies. Various methods of blood collection have been described for amphibians. Most can be cumbersome (venipucture of femoral vein, ventral abdominal vein or lingual venus plexus) or result in pain or deleterious health consequences (cardiac puncture and toe-clipping). We describe an easy and practical technique to collect blood from frogs and toads that can be used in multiple species and is minimally invasive. The technique consists of puncturing either the facial or, less commonly, the musculo-cutaneous vein and collecting the blood with a capillary tube. These veins run dorsal and parallel to the maxillary bone and can be accessed by quick insertion and withdrawal of a needle through the skin between the upper jawline and the rostral or caudal side of the tympanum. The needle should be of 27 or 30 gauge for anurans weighing more or less than 25 g, respectively. Although the technique has been used by some amphibian researchers for years, it is little known by others and has never been fully described in a peer-reviewed publication.

Journal of Veterinary Behavior: Clinical Applications and Research, 2014

ABSTRACT The objective of this study was to evaluate the response of healthy housebound domestic ... more ABSTRACT The objective of this study was to evaluate the response of healthy housebound domestic cats to the simultaneous provision of 2 litterboxes of differing sizes by recording the average daily frequency of urination and defecation in each box. Forty-three households with 74 privately owned cats were each provided with 2 different-sized plastic containers, with the larger box being 86 cm in length, exceeding the size of commercially available litterboxes. Owners were also provided with an unlimited supply of clumping cat litter and a logbook to record daily urine and fecal deposits in the boxes as they were scooped over a 4-week period. The 2 litterboxes were initially placed at opposite sides of the same room in the owner's home. After 2 weeks, the boxes were emptied completely, refilled with clean clumping litter, and replaced in the opposite location. Results were recorded as simple counts of urine and fecal deposits for each day and each household. Over the 28-day period, there were a total of 5031 urine and fecal deposits in the larger boxes and 3239 urine and fecal deposits in the regular boxes. The effects of phase (days 1-14 vs. 15-28) and box size (regular vs. large) on the number of deposits per cat were evaluated using a linear mixed model. In addition to evaluating phase and box size, the effects of number of cats in the house, their average age, and gender were also evaluated. Urine deposits were significantly more frequent than fecal deposits. Large boxes were preferentially selected over regular boxes in both phases, but this difference was greater in phase 1 than phase 2. Further analysis indicated that there was a location preference during the first 2 days in phase 2, and this effect decreased as the study progressed. Results indicate that most cats show a definite preference for a larger litterbox than is typically available to them in homes and that other factors such as box cleanliness and location may have a compounding influence on this choice.

Diseases of Aquatic Organisms, 2010

Theriogenology, 2015

There is a growing interest in chemical sterilization as an alternative to surgical castration in... more There is a growing interest in chemical sterilization as an alternative to surgical castration in large-scale sterilization campaigns to control canine populations. An important step toward understanding the short-term and long-term effects of chemical sterilants is to determine their impact on blood testosterone concentrations, particularly as these could influence dog behavior after treatment. A field trial was conducted with 118 free-roaming male dogs in the Chilean Patagonia, where 36 dogs were chemically sterilized using EsterilSol, 39 dogs were surgically castrated, and 43 dogs remained intact as controls. Blood testosterone levels were determined at four time periods: on enrollment 6 months before treatment (t-6m), at the time of treatment (t0, within one hour after surgical castration or chemical sterilization and during a concurrent 2-week period for the control group), four (t+4m), and six (t+6m) months after treatment. Intrinsic and temporal factors were evaluated; age wa...

The Canadian veterinary journal. La revue vétérinaire canadienne, 2010

Trichomoniasis was diagnosed in multiple incidents of mortality in wild purple finch (Carpodacus ... more Trichomoniasis was diagnosed in multiple incidents of mortality in wild purple finch (Carpodacus purpureus) and American goldfinch (Carduelis tristis) in the Canadian Maritimes. Birds exhibited regurgitation, emaciation, and hyperplastic oropharyngitis, ingluvitis, and esophagitis. Trichomonas gallinae was identified by histopathology and polymerase chain reaction (PCR). Trichomoniasis (trichomonosis) is an emerging disease in wild finches of eastern Canada.

Veterinary Research, 2014

The Journal of general virology, Jan 15, 2015

Amphibian populations suffer massive mortalities from infection with Frog virus 3 (FV3, Ranavirus... more Amphibian populations suffer massive mortalities from infection with Frog virus 3 (FV3, Ranavirus, Iridoviridae), a pathogen also involved in mortalities of fish and reptiles. Experimental oral infection with FV3 in captive-raised adult wood frogs, Rana sylvatica [Lithobates sylvaticus], was performed as the first step in establishing a native North American animal model of ranaviral disease to study pathogenesis and host-response. Oral dosing was successful; LD50 was 10^2.93 (2.42-3.44) pfu for frogs averaging 35 mm in length. Onset of clinical signs occurred 6-14 days post-infection (dpi) (median 11 dpi) and time-to-death 10-14 dpi (median 12 dpi). Each ten-fold increase in virus dose increased the odds of dying by 23-fold and accelerated onset of clinical signs and death by approximately 15%. Ranavirus DNA was demonstrated in skin and liver of all frogs that died or were euthanized because of severe clinical signs. Shedding of virus occurred in feces (7-10 dpi; 3-4.5 d before dea...

Preventive veterinary medicine, 2012

Enzyme-linked immunosorbent assays (ELISAs) have been used as a diagnostic tool to quantify level... more Enzyme-linked immunosorbent assays (ELISAs) have been used as a diagnostic tool to quantify levels of gastrointestinal nematodes in dairy cattle by measuring Ostertagia ostertagi antibodies in milk. Higher levels of O. ostertagi antibodies measured by ELISA methods, referred to as optical density ratios (ODRs), are associated with decreased milk production in dairy cattle. On-farm management practices (e.g. pasturing techniques and anthelmintic usage) can influence the exposure of cattle to nematode infections and the magnitude of acquired worm burdens. Additionally, environmental and climatic factors, such as land elevation and precipitation, may also influence the levels of gastrointestinal parasitism. This repeated cross-sectional study investigated the effect of farm management practices and surrounding environmental factors on bulk tank (BT) ODRs in herds from provinces across Canada, and further examined the potential effects of various anthelmintic treatment protocols on BT O...

Veterinary Parasitology, 2010

The impact of various milk handling stressors were analyzed using a commercially available enzyme... more The impact of various milk handling stressors were analyzed using a commercially available enzyme-linked immunosorbent assay (ELISA) test measuring Ostertagia ostertagi antibodies in milk from dairy cattle (Svanovir). An indirect ELISA has the ability to determine the amount of milk production losses related to intestinal parasitism. The ELISA test recommends fresh defatted milk, however, milk collected from Dairy Herd Improvement (DHI) programs in North America undergo many stressors, including, heating, freezing and are not defatted. Normalized optical density ratios (ODRs) were compared between fresh defatted milk and milk subjected to one or more stressors with a linear mixed model accounting for differences in variation between the fresh and the frozen samples. Concordance correlation coefficients were also analyzed for comparisons to other similar studies. After accounting for random cow and container effects, the treatment factors interacted with each other (p<0.001). Biologically interesting contrasts were created to explain the interaction. The estimated difference in ODR between the milk samples handled according to recommendations of the manufacturers of Svanovir and the whole milk samples that were subjected to the most extreme treatment (heated, frozen, thawed, and re-frozen for 4 weeks) was 0.062 (p<0.001). This difference represented less than 5% of the range, and was thus considered biologically negligible. Frozen whole milk processed by DHI programs, the most likely method of collecting on-farm samples in North America, will likely yield reliable results for the indirect ELISA tests, particularly, Svanovir.

Preventive Veterinary Medicine, 2013

Freedom from infection modeling, using scenario trees, has become an established methodology and ... more Freedom from infection modeling, using scenario trees, has become an established methodology and is well described in the literature. However, standards for organizing and reporting the surveillance information incorporated into such models are less developed. Canada has been routinely testing for Trichinella spiralis in market hogs in federally inspected slaughter plants since the late 1990s. By way of presenting our work on T. spiralis in Canadian hogs, we propose that information in surveillance models be organized in distinct categories, each with specific parameters and values that are thoroughly described and justified. The proposed categories are: (1) definitions for the objectives, (2) initial time period, (3) inputs, (4) data, (5) model settings, (6) outputs, and (7) validation. Having a standardized manner of reporting such studies will facilitate their validation and expedite their evaluation by experts in the field and their use in trade negotiations.

Preventive Veterinary Medicine, 2015

Please cite this article in press as: Tenzin, T., et al., Comparison of mark-resight methods to e... more Please cite this article in press as: Tenzin, T., et al., Comparison of mark-resight methods to estimate abundance and rabies vaccination coverage of free-roaming dogs in two urban areas of south Bhutan. PREVET (2015), http://dx.Please cite this article in press as: Tenzin, T., et al., Comparison of mark-resight methods to estimate abundance and rabies vaccination coverage of free-roaming dogs in two urban areas of south Bhutan. PREVET (2015), http://dx.

Veterinary Pathology, 2013

Intratesticular injection of EsterilSol (zinc gluconate neutralized with arginine) is a chemical ... more Intratesticular injection of EsterilSol (zinc gluconate neutralized with arginine) is a chemical sterilant for male dogs sometimes used in population control campaigns. Adverse reactions have been reported in 1% to 4% of treated dogs, but detailed histomorphologic descriptions are lacking. During a behavioral study conducted in the Chilean Patagonia in 2012, severe necrosuppurative orchitis and ulcerative dermatitis were observed in 2 of 36 (6%) dogs sterilized with EsterilSol according to the manufacturer's instructions. Reactions were noted on days 8 and 7 postinjection and required scrotal ablation on days 8 and 13, respectively; neither reaction was associated with the injection site. Although self-trauma following administration may have contributed, the cause of the adverse reactions is uncertain. EsterilSol is a relatively uncomplicated method to sterilize male dogs, but the occurrence of severe adverse reactions several days after administration emphasizes the need for the provision of long-term monitoring and veterinary care during sterilization campaigns using this product.

Veterinary Pathology, 2013

Many subtypes of low-pathogenicity avian influenza (LPAI) virus circulate in wild bird reservoirs... more Many subtypes of low-pathogenicity avian influenza (LPAI) virus circulate in wild bird reservoirs, but their prevalence may vary among species. We aimed to compare by real-time reverse-transcriptase polymerase chain reaction, virus isolation, histology, and immunohistochemistry the distribution and pathogenicity of 2 such subtypes of markedly different origins in Mallard ducks (Anas platyrhynchos): H2N3 isolated from a Mallard duck and H13N6 isolated from a Ring-billed Gull (Larus delawarensis). Following intratracheal and intraesophageal inoculation, neither virus caused detectable clinical signs, although H2N3 virus infection was associated with a significantly decreased body weight gain during the period of virus shedding. Both viruses replicated in the lungs and air sacs until approximately day 3 after inoculation and were associated with a locally extensive interstitial, exudative, and proliferative pneumonia. Subtype H2N3, but not subtype H13N6, went on to infect the epithelia of the intestinal mucosa and cloacal bursa, where it replicated without causing lesions until approximately day 5 after inoculation. Larger quantities of subtype H2N3 virus were detected in cloacal swabs than in pharyngeal swabs. The possible clinical significance of LPAI virus-associated pulmonary lesions and intestinal tract infection in ducks deserves further evaluation.

Preventive Veterinary Medicine, 2010

The aim of this study was to explore whether anti-Ostertagia ostertagi antibody levels measured b... more The aim of this study was to explore whether anti-Ostertagia ostertagi antibody levels measured by ELISA in individual milk samples hold promise as a decision parameter for either herd-level decisions or selective anthelmintic treatments by investigating (1) the relationship between individual and bulk-tank milk ELISA results; (2) the relationships of individual milk ELISA results with non-parasitic cow factors and (3) the relationship between individual milk ELISA results and the milk production response after anthelmintic treatment. Twelve farms were randomly allocated to a whole-herd treatment with eprinomectin or a placebo in October 2004 and individual milk samples and a bulk-tank milk sample were collected 1 month before and 1 month after treatment. Linear mixed models were used to investigate the associations of ELISA results with (a) breed, actual milk production, lactation stage, somatic cell count, age and sampling month and (b) the milk production response after anthelmintic treatment. There was a reasonable correlation between the mean individual and bulk-tank milk ELISA results (r=0.72). Individual cow ELISA results increased with higher lactation number and were lower in November than September. The associations with the other non-parasitic factors were weak and not significant. Milk yield responses to anthelmintic treatment were greater when treatment was given in early lactation and increased with the pre-treatment ELISA result and cow age. However, these latter two interaction terms were not significant when they were put in the model together. We conclude that (1) O. ostertagi ELISA results from individual milk samples may provide more information on the herd's parasitic status than a single bulk-tank milk result; (2) lactation number should be taken into account when interpreting ELISA results from individual milk samples and (3) the value of the O. ostertagi antibody level in individual cow milk samples to predict individual production responses after anthelmintic treatment remains equivocal.

Preventive Veterinary Medicine, 2013

Gastrointestinal nematodes, such as Ostertagia ostertagi and several species of Cooperia, are ubi... more Gastrointestinal nematodes, such as Ostertagia ostertagi and several species of Cooperia, are ubiquitous in temperate climates and have been shown to have detrimental effects on production in adult dairy cattle. A published meta-analysis demonstrated that overall, producers lose approximately 0.35 kg of milk per parasitized cow per day. Enzyme-linked immunosorbent assays (ELISAs) have the ability to quantify nematode infections in cattle, and thus, could be used to estimate the amount of milk production loss due to differing levels of parasitism at the individual cow level. ELISA results from individual cow milk samples were used to predict milk production response following a randomized anthelmintic treatment in a large field trial. To increase statistical power, the data collected from this field trial was pooled with data from two other published field trials to form an individual patient data meta-analysis (IPDMA). The ability to predict the effect of anthelmintic treatment on milk production depends on the level of parasitism quantified by an ELISA measuring milk antibodies against O. ostertagi, and reported as optical density ratios (ODRs). Therefore, the estimates from the interaction between ODR and treatment on milk production were used to determine how well the ODR predicted the response of the treatment. It was anticipated that the relationship between milk production and ODR was unlikely to be linear, so fractional polynomials were applied to the continuous ODR values. The interaction in the field trial showed a trend (p=0.138) toward a beneficial treatment effect when the individual ODR values, measured in late lactation and using Svanovir(®), were greater than 0.12. When individual data from two other similar studies were included in an IPDMA, the interaction terms became statistically significant (p=0.009) indicating that there is a beneficial treatment effect when ODR values are slightly elevated. A graph was used to demonstrate the treatment effect (the estimated difference of kg/cow/day of milk yield between the treated and placebo cows), with 95% confidence intervals, as the ODR values increase. It is important to note that the methods of quantifying the ODR values differed between the three studies in the IPDMA, therefore some caution should be used when using these final estimated values. However, the shape and magnitude of the treatment effects, as well as the other fixed model estimates, were very similar between the field trial and the IPDMA suggesting that any bias would likely be minimal.

Journal of Wildlife Diseases, 2012

Collection of blood from amphibians, as in other classes of vertebrate animals, is essential to e... more Collection of blood from amphibians, as in other classes of vertebrate animals, is essential to evaluate parameters of health, diagnose hemoparasitism, identify viral and bacterial pathogens, and measure antibodies. Various methods of blood collection have been described for amphibians. Most can be cumbersome (venipucture of femoral vein, ventral abdominal vein or lingual venus plexus) or result in pain or deleterious health consequences (cardiac puncture and toe-clipping). We describe an easy and practical technique to collect blood from frogs and toads that can be used in multiple species and is minimally invasive. The technique consists of puncturing either the facial or, less commonly, the musculo-cutaneous vein and collecting the blood with a capillary tube. These veins run dorsal and parallel to the maxillary bone and can be accessed by quick insertion and withdrawal of a needle through the skin between the upper jawline and the rostral or caudal side of the tympanum. The needle should be of 27 or 30 gauge for anurans weighing more or less than 25 g, respectively. Although the technique has been used by some amphibian researchers for years, it is little known by others and has never been fully described in a peer-reviewed publication.

Journal of Veterinary Behavior: Clinical Applications and Research, 2014

ABSTRACT The objective of this study was to evaluate the response of healthy housebound domestic ... more ABSTRACT The objective of this study was to evaluate the response of healthy housebound domestic cats to the simultaneous provision of 2 litterboxes of differing sizes by recording the average daily frequency of urination and defecation in each box. Forty-three households with 74 privately owned cats were each provided with 2 different-sized plastic containers, with the larger box being 86 cm in length, exceeding the size of commercially available litterboxes. Owners were also provided with an unlimited supply of clumping cat litter and a logbook to record daily urine and fecal deposits in the boxes as they were scooped over a 4-week period. The 2 litterboxes were initially placed at opposite sides of the same room in the owner's home. After 2 weeks, the boxes were emptied completely, refilled with clean clumping litter, and replaced in the opposite location. Results were recorded as simple counts of urine and fecal deposits for each day and each household. Over the 28-day period, there were a total of 5031 urine and fecal deposits in the larger boxes and 3239 urine and fecal deposits in the regular boxes. The effects of phase (days 1-14 vs. 15-28) and box size (regular vs. large) on the number of deposits per cat were evaluated using a linear mixed model. In addition to evaluating phase and box size, the effects of number of cats in the house, their average age, and gender were also evaluated. Urine deposits were significantly more frequent than fecal deposits. Large boxes were preferentially selected over regular boxes in both phases, but this difference was greater in phase 1 than phase 2. Further analysis indicated that there was a location preference during the first 2 days in phase 2, and this effect decreased as the study progressed. Results indicate that most cats show a definite preference for a larger litterbox than is typically available to them in homes and that other factors such as box cleanliness and location may have a compounding influence on this choice.

Diseases of Aquatic Organisms, 2010