Neutered Dogs Research Articles

Markers of Oxidative Stress in Dogs with Myxomatous Mitral Valve Disease are Influenced by Sex, Neuter Status, and Serum Cholesterol Concentration.

BackgroundCardiovascular disease has been associated with oxidative stress, which has been suggested to contribute to myocardial remodeling in human patients. Little is known about the relationship between myxomatous mitral valve disease (MMVD) and oxidative stress in dogs.ObjectiveTo determine whether clinical stage of MMVD is associated with changes in the plasma concentrations of certain markers of oxidative stress in clinically healthy dogs and dogs with MMVD.AnimalsSeventy five privately owned dogs: 59 cavalier King Charles Spaniels (CKCS) with different severities of MMVD and 16 dogs of different breeds with clinical signs of congestive heart failure (CHF) caused by MMVD.MethodsMarkers of oxidative stress including malondialdehyde (MDA), oxidized low‐density lipoprotein (oxLDL), and vitamin E (α‐tocopherol and γ‐tocopherol) were measured in plasma and their association with clinical stage of MMVD was assessed by regression analyses.ResultsPlasma oxLDL concentration was significantly lower in female dogs compared with males (P = .01). Significantly higher plasma γ‐tocopherol concentrations were found in neutered (P = .003) dogs. Vitamin E (α‐tocopherol [P = .0004] and γ‐tocopherol [P = .003]) was associated with body condition score (BCS), but the association disappeared when cholesterol was included in the analyses. All markers of oxidative stress (MDA, oxLDL, and vitamin E) were positively associated with serum cholesterol concentration (P ≤ .04), but none were associated with clinical stage of MMVD.ConclusionsIn conclusion, markers of oxidative stress are associated with sex, BCS, neuter status, and cholesterol. The results cannot confirm a relationship between oxidative stress and clinical stage of the disease in dogs with MMVD.

Effect of dietary protein intake on the body composition and metabolic parameters of neutered dogs.

Neutering is a common veterinary recommendation and is often associated with obesity development. Thus, the aim of the present study was to evaluate the effects of two different amounts of protein intake by neutered dogs regarding maintenance energy requirement (MER), body composition, and biochemical and hormonal parameters. A total of fourteen healthy adult dogs were fed either a diet containing 59·7 g protein/1000 kcal (4184 kJ) (P60) or a diet with 94·0 g protein/1000 kcal (4184 kJ) (P94) for 26 weeks after neutering to maintain their body weight prior to neutering. A mixed model was fitted to verify diet, time and diet × time interaction effects on biochemical parameters, serum concentrations of insulin, glucagon, leptin and insulin-like growth factor-1 (IGF-1). MER and the body composition data were evaluated within diets (paired t test) and within times (unpaired t test). A time effect was found for fructosamine, TAG, total lipids and IGF-1 serum concentrations. The diet × time interaction was significant for glucagon (P < 0·05). No differences between diets in the MER within each time were found. However, there was a reduction in the MER of dogs fed the P60 diet 26 weeks after neutering (P = 0·042). The fat body mass of dogs fed the P60 diet increased (P < 0·05) after neutering, even without a body-weight change. Some of the biochemical parameters changed over time, but all remained within the normal range. For the period evaluated in the present study, a diet with 94·0 g of protein/1000 kcal (4184 kJ) metabolisable energy seems to be a beneficial nutritional strategy to maintain the MER and the body composition of dogs after neutering.

Effect of enzyme supplements on macronutrient digestibility by healthy adult dogs.

Some enzyme supplement products claim benefits for healthy dogs to compensate for alleged suboptimal production of endogenous enzymes and the loss of enzymes in commercial pet foods secondary to processing. The objective of the current study was to determine macronutrient and energy digestibility by healthy adult dogs fed a commercial maintenance diet with or without supplementation with plant- and animal-origin enzyme products at the dosage recommended by their respective manufacturers. A group of fourteen healthy neutered adult Beagle dogs (average age 8 years) was divided into two equal groups and fed the basal diet alone and then with either the plant- or animal-origin enzyme supplement in three consecutive 10-d periods; the treatment groups received the opposite enzyme supplement in the third period. Digestibility in each period was performed by the total faecal collection method. Serum trypsin-like immunoreactivity (TLI) was measured at the end of each trial. Data were analysed by repeated measures and the α level of significance was set at 0·05. There were no differences in energy and nutrient digestibility between enzyme treatments. When comparing basal with enzyme supplementation, fat digestibility was higher for the basal diet compared with the animal-origin enzyme treatment, which could be a period effect and was not biologically significant (94·7 v. 93·5%). Serum TLI was not affected by supplementation with either enzyme product. Exogenous enzyme supplementation did not significantly increase digestibility of a typical commercial dry diet in healthy adult dogs and routine use of such products is not recommended.

Urinary 3-hydroxypropyl mercapturic acid (3-HPMA) concentrations in dogs with acute spinal cord injury due to intervertebral disc herniation

The aim of this study was to investigate urinary 3-hydroxypropyl mercapturic acid (3-HPMA), a metabolite of acrolein, as a novel biomarker in acute spinal cord injury (ASCI) due to intervertebral disc herniation in dogs. Urine from 10 client-owned dogs with ASCI collected at presentation and 10 control dogs was analyzed for 3-HPMA. The median urinary 3-HPMA concentration in ASCI dogs was significantly higher than in control dogs, but was not correlated with the severity of ASCI. The median urinary 3-HPMA concentration in intact dogs was higher than in neutered dogs. Higher urinary 3-HPMA concentrations in dogs after ASCI support a role for acrolein, a cytotoxic by-product of lipid peroxidation, in canine ASCI. Urinary 3-HPMA could be used as a biomarker in future clinical trials to measure the effect of therapeutic intervention of reducing acrolein after ASCI.

The epidemiology of patellar luxation in dogs attending primary-care veterinary practices in England.

BackgroundCanine patellar luxation is one of the most common orthopaedic disorders of dogs and is a potential welfare concern because it can lead to lameness, osteoarthritis and pain. However, there are limited epidemiological data on the disorder relating to the general population of dogs in England. This study aimed to investigate the VetCompass Programme database of dogs attending primary-care veterinary practices in England to report on the prevalence, risk factors and clinical management of diagnosed patellar luxation cases.ResultsThe study included all dogs with at least one electronic patient record in the VetCompass database from September 1st, 2009 to August 31st, 2014. Candidate patellar luxation cases were identified using free-text word searching of the clinical notes and VeNom diagnosis term fields. Univariable and multivariable binary logistic regression modelling was used for risk factor analysis.The overall dataset comprised 210,824 dogs attending 119 clinics in England. The prevalence of patellar luxation diagnosis in dogs was 1.30 % (95 % confidence interval (CI) 1.21–1.39). Of the 751 incident cases, 293 (39.0 %) received medical management, 99 (13.2 %) received surgical intervention and 28 (3.7 %) were referred for further management.Multivariable modelling documented 11 breeds with increased odds of patellar luxation compared with crossbred dogs, including the Pomeranian (odds ratio [OR]: 6.5, 95 % CI 4.0–10.7, P < 0.001), Chihuahua (OR: 5.9, 95 % CI 4.4–7.9, P < 0.001), Yorkshire Terrier (OR: 5.5, 95 % CI 4.3–7.1, P < 0.001) and French Bulldog (OR: 5.4, 95 % CI 3.1–9.3, P < 0.001). Dogs with bodyweight below their mean for breed and sex had a 1.4 times odds of diagnosis (95 % CI 1.2–1.6, P < 0.001). Dogs aged ≥ 12.0 years showed 0.4 times the odds (95 % CI 0.3–0.5, P < 0.001) compared with dogs aged < 3.0 years. Females had 1.3 times the odds (95 % CI 1.1–1.5, P < 0.001), neutered dogs had 2.4 times the odds (95 % CI 1.8–3.2, P < 0.001) and insured dogs had 1.9 times the odds (95 % CI 1.6–2.3, P < 0.001).ConclusionsPatellar luxation warrants inclusion as a welfare priority in dogs and control strategies that include this disorder should be considered as worthwhile breeding goals, especially in predisposed breeds.

Neutering of German Shepherd Dogs: associated joint disorders, cancers and urinary incontinence.

German Shepherd Dogs are important in police and military work, and are a popular family pet. The debilitating joint disorders of hip dysplasia, cranial cruciate ligament tear (CCL) and elbow dysplasia can shorten a dog's useful working life and impact its role as a family member. For this study, veterinary hospital records were examined over a 14.5‐year period on 1170 intact and neutered (including spaying) German Shepherd Dogs for joint disorders and cancers previously associated with neutering. The diseases were followed through 8 years of age, with the exception of mammary cancer (MC) in females that was followed through 11 years. The cancers followed, apart from mammary, were osteosarcoma, lymphoma, hemangiosarcoma and mast cell tumour. In intact males, 7% were diagnosed with one or more joint disorders, while in males neutered prior to a year of age, a significantly higher 21% were diagnosed with one or more joint disorders. In intact females, 5% were diagnosed with one or more joint disorders, while in females neutered prior to a year of age, this measure was significantly increased to 16%. The increased joint disorder incidence mostly associated with early neutering was CCL. MC was diagnosed in 4% of intact females compared with less than 1% in females neutered before 1 year. The occurrence of the other cancers followed through 8 years of age was not higher in the neutered than in the intact dogs. Urinary incontinence, not diagnosed in intact females, was diagnosed in 7% of females neutered before 1 year, a significant difference. These findings, profiling the increase in joint disorders associated with early neutering, should help guide the timing of neutering for this breed.

Dog overpopulation and burden of exposure to canine distemper virus and other pathogens on Santa Cruz Island, Galapagos

Dog overpopulation and diseases are hazards to native island species and humans on the Galapagos. Vaccination and importation of dogs are prohibited on the Galapagos. Risk management of these hazards requires the use of science-based risk assessment and risk communication. The objectives of the study reported here were (i) to estimate the human:dog ratio and (ii) the prevalence of and identify exposure factors associated with positive antibody titers to canine distemper virus (CDV) and other pathogens, as well as infection with intestinal parasites in owned dogs on Santa Cruz Island, Galapagos in September 2014. The observed human:dog ratio was 6.148:1 which extrapolates to 2503 dogs (two times more than a recent dog count conducted by Galapagos Biosecurity Agency in March 2014). The proportion of spayed female dogs (50%) was higher, compared to neutered male dogs (30%) (p=0.04). Prevalence of dogs with positive antibody titers to CDV was 36% (95% CI=26, 46%), to canine parvovirus was 89% (95% CI=82, 95%), and to canine adenovirus was 40% (95% CI=30, 51%). The frequency of seropositive dogs to CDV was lower in urban dogs (26%), compared to rural dogs (53%) (p<0.05). A positive interaction effect between rural residence and spay/neuter status on seropositivity to CDV was observed, which we discuss in this report. Because vaccination is prohibited, the dog population on Santa Cruz is susceptible to an outbreak of CDV (particularly among urban dogs) with potential spill over to marine mammals. Dog’s age (1–2 or 3–14 years old, compared to younger dogs), and residence (rural, urban) were associated with positive antibody titers to parvovirus, adenovirus, Ehrlichia spp., or Anaplasma spp., as well as infection with Ancylostoma spp., an intestinal parasite in dogs that can be transmitted to humans, particularly children. These results provide the most comprehensive assessment of dog overpopulation and exposure to CDV and other pathogens on the Galapagos to date.

Effect of the gonadal integrity and the gender on responses of bone crestal levels in dogs with two dental prosthetic abutment types

Fourteen adult mongrel dogs (5 intact and 9 neutered) comprising seven males and seven females were used to evaluate change in levels of alveolar crestal bone after implanting two types of dental abutments. Implants were surgically placed in both mandibular fourth premolar zones and restored with conventional (CONV) and platform switching (PFS) abutments. Both abutments were evaluated in each dog. The study lasted 180 days; restoration was performed at Day 60 postsurgical-placed implants and alveolar crestal bone levels was evaluated on Days 0, 30, 60, and 90 post-restoration (cemented crown) through indirect measurement using a digital X-ray sensor. Experimental data were analysed using a completely randomized design: the experimental unit was the dog (random effect), the treatment was the abutment type (fixed effect), and crestal bone level of each implant side (mesial and distal) was the observation. In addition, the gonadal integrity (intact and neutered) and the gender (male and female) were included in the statistical analysis to evaluate their role on the magnitude of changes (interactions) on alveolar crestal bone levels. The average of crestal bone loss was 0.400 ± 0.186 mm. In general, dogs with CONV had a greater (27.3%, P 0.77) between gender and abutment type. Similarly, as a sole factor of variation, gender had no effect (P = 0.26) on crestal bone level responses to abutment type (-0.401 vs -0.385 mm for males and females, respectively). Regardless of the type of abutment, males and females had a similar (P = .65) crestal bone loss (-0.405 vs. -0.393), while neutered dogs showed a greater (30.8%, P < 0.01) crestal bone loss compared with intact dogs. In conclusion, dogs with PFS showed less crestal bone loss than CONV; however, regardless of gender, this response only was maintained in intact dogs; therefore the gonadal condition has an effect on the magnitude of changes of the alveolar crestal bone levels in their response to abutment type in dogs with dental implants.

Prevalence of canine behavior problems related to dog-human relationship in South Korea—A pilot study

This population study examined the prevalence of 10 common, broadly classified behavior problems exhibited by dogs reported by 174 dog owners in South Korea. Most respondents (147; 84.5%) stated that their dog exhibited at least one behavior problem. The main behavior problems reported by owners were excessive barking (82; 47.1% of all owners), inappropriate elimination (71; 40.8%), aggressive behavior (62; 35.6%), fearfulness (52; 29.9%), and separation anxiety (48; 27.6%). Male dogs were more likely to exhibit excessive barking and destructiveness than female dogs. Interestingly, neutered dogs showed more unacceptable behaviors than intact dogs, particularly excessive barking, aggression, and excessive activity. Young dogs were less likely than adult dogs to exhibit fearfulness or separation anxiety, but adult dogs were less likely than young dogs to exhibit destructiveness. Statistically significant associations were detected between at least one obedience training session per week and reduced inappropriate elimination (P < 0.05); between no obedience training and increased fearfulness (P < 0.05); between fewer walks and excessive barking (P < 0.05); and between being left home alone for 3 to 6 hours per day and excessive barking (P < 0.05), inappropriate elimination (P < 0.05), and destructiveness (P < 0.05). These findings suggest that there is a need for further detailed analyses of the various factors involved in behavioral problems in companion dogs. Such studies could be useful in improving the quality of the dog-human relationship and animal welfare in South Korea because they could lead to prevention of undesirable behavioral problems and reduction in dog relinquishment.

Influence of ovariohysterectomy and deslorelin acetate on the spontaneous activity of the rabbit urinary bladder in vitro

Lower urinary tract symptoms are not only a serious health problem but also a substantial sociologic issue affecting human beings and companion animals. Estrogen deficiency is considered an etiologic factor of urinary incontinence in postmenopausal women and spayed female dogs. However, insufficient effectiveness of hormonal therapy has caused an intensive search for new therapeutic options. GnRH analogs have positive clinical effects in neutered female dogs suffering from incontinence, but the mechanism of action is not known. The aim of our study was to determine the effect of long-acting deslorelin acetate on the spontaneous activity of urinary bladder sections from a rabbit model of long-term estrogen deprivation. The study was conducted on 21 female New Zealand White rabbits divided into the following groups: control group, ovariohysterectomized (OHX) group, and ovariohysterectomized group given a deslorelin acetate implant. Urinary bladders were excised immediately after sacrifice, and the spontaneous activity of dorsal and ventral strips of the bladder body was examined in organ bath chambers. The amplitude and frequency of the spontaneous contractions were evaluated. Most of the sections developed spontaneous activity. Ovariohysterectomy caused a decrease in the amplitude of spontaneous contractions of the tissues obtained only from the dorsal part of the bladder body. After OHX, the frequency was higher compared with the control group in both parts of the bladder. Deslorelin acetate did not significantly affect the spontaneous contraction amplitude but caused a decrease in the frequency in the dorsal and ventral parts of the bladder. In conclusion, long-term changes in the levels of hormones and other regulatory substances associated with the reproductive system are related to altered spontaneous activity of the urinary bladder, which may impact the symptoms of urgency and incontinence appearing in women after menopause and in female animals after gonadectomy. However, long-acting deslorelin acetate partially reverses the effect of OHX on the spontaneous activity of the bladder. This process might underlie the positive effects of GnRH analogs in incontinent spayed female dogs.

Visibly Marked and Microchipped Lost Dogs Have a Higher Chance to Find Their Owners in Belgrade

Abstract The aim of the study was to analyse the demographic characteristics of lost and found dogs in Belgrade, Serbia. The demographic data concerning the 246 lost and 81 found dogs in the period of 5 consecutive years (January, 2009 to January 2014) was sampled and analysed from the data bases of four organizations for animal protection in Belgrade. The recovery rate of lost dogs and the chance to be reunited again with their owners was 33%. The highest recovery rate was estimated in the category of lost dogs with visible marks such as tags or collars (30%).The chi-square test disclosed that besides dogs with special visible marks, significantly more females, light colour coated, friendly/sociable and neutered dogs were reunited with their owners (P&lt;0.0001).

The effect of prolonged exposure to morphine on canine cerebral 5-HT2A receptors measured with 123I-R91150 SPECT

Down-stream neuronal alterations, including changes in the 5-HT-2A receptor system, play an important role in the etiology and treatment of depression. The present study examined the effect of prolonged opioid treatment on cerebral 5-HT2A receptors. Cerebral 5-HT2A receptor availability was estimated in seven healthy five-year-old female neutered Beagle dogs pre and post 10-day morphine treatment (oral sustained release morphine 20mg twice daily for 10 days) with 123I-R-91150, a 5-HT2A selective radioligand, and SPECT. 5-HT2A receptor binding indices (BI) for the frontal, parietal, temporal and occipital cortex and the subcortical region were calculated. Statistical analysis was performed using a linear mixed-effect model with treatment as fixed effect and dog as random effect. Morphine treatment significantly (P≤0.05) lowered 5-HT2A BIs in the right and left frontal cortex, the right and left temporal cortex, the right and left parietal cortex, and the subcortical region. The decreased cerebral 5-HT2A receptor availability following prolonged morphine exposure provides further evidence for an interaction between the opioid and serotonergic system.

Effects of space allowance on the behaviour of long-term housed shelter dogs

The aim of this study was to assess the effects of space allowance (4.5m2/head vs. 9m2/head) on the behaviour of shelter dogs (Canis familiaris) at different times of the day (from 10:30 to 13:30 vs. from 14:30 to 17:30), and the dogs’ preference between two types of beds (fabric bed vs. plastic basket). Twelve neutered dogs (seven males and five females aged 3–8 years) housed in pairs were observed using a scan sampling recording method every 20s for a total of 14,592 scans/treatment. An increase in space allowance increased general level of activity (risk ratio (RR)=1.34), standing (RR=1.37), positive social interactions (RR=2.14), visual exploration of the environment (RR=1.21), and vocalisations (RR=2.35). Dogs spent more time in the sitting (RR=1.39) or standing (RR=1.88) posture, in positive interactions (RR=1.85), and active visual exploration (RR=1.99) during the morning than in the afternoon. The dogs were more often observed in the fabric bed than in the plastic basket (53% vs. 15% of total scans, p<0.001).Results suggest that a 9.0m2/head space allowance could be more beneficial to dogs than one of 4.5m2.

Human directed aggression in domestic dogs (Canis familiaris): Occurrence in different contexts and risk factors

The consequence for dogs of showing aggression towards people is often euthanasia or relinquishment. Aggression is also a sign of compromised welfare in dogs, and a public health issue for people. The aims of this study were to estimate the numbers of dogs showing aggression to people in three contexts (unfamiliar people on entering, or outside the house, and family members); identify whether these co-occur, and investigate risk factors for aggression in each context using multivariable analyses. In this cross-sectional convenience sample of UK dog owners, aggression (defined as barking, lunging, growling or biting) towards unfamiliar people was more common than towards family members. Most dogs did not show aggression in multiple contexts, suggesting that this behaviour may be a learnt response to situations rather than a general characteristic of individuals. Older owners were less likely to report family directed aggression or aggression to unfamiliar people entering the house than younger ones. Female owners were also less likely to report aggression to visitors. Increasing dog age was associated with increased risk of aggression to unfamiliar people both entering and outside the house. Female neutered dogs had a reduced risk of aggression in all three contexts. Dogs in the Utility and Hounds groups as defined by the UK Kennel Club had an increased risk of aggression to family members compared to cross-breeds, although post hoc analyses identified no specific increased individual breed risks. Gundogs has a reduced risk of aggression to unfamiliar people both entering and outside of the house. Where owners acquired their dog was a risk factor for aggression to household members. Attendance at puppy classes reduced risk of aggression to unfamiliar people both in and out of the house; attending ring-craft classes were associated with reduced risk when outside the house. The use of positive punishment or negative reinforcement based training methods was associated with increased chance of aggression to family and unfamiliar people outside the house. Importantly, for all types of aggression, the variables measured explained a relatively small amount of the variance (<10%) between aggressive and non-aggressive animals, suggesting a much greater importance of factors specific to the experience of individual dogs in the development of aggression. These data suggest that although general characteristics of dogs and owners may be a factor at population level, it would be inappropriate to make assumptions about an individual animal's risk of aggression to people based on characteristics such as breed.

Prevalence and antimicrobial resistance of canine urinary tract pathogens

This study aims to describe the incidence and risk factors for positive urinary tract culture, the prevalence of urinary tract pathogens in single organism and mixed cultures and changes in their antimicrobial resistance over 10 years. A retrospective review of computer records detailing canine urine samples submitted between August 1999 and September 2009 for culture and sensitivity in a UK tertiary referral hospital is described. 17.5 per cent of 5923 samples (670of4530 dogs) were positive cultures. 85.3 per cent of cultures yielded a single isolate. The prevalence of bacterial species differed between mixed and single isolate cultures. Entire and neutered female dogs were more likely to return positive cultures than male dogs (OR=2.5 and 1.5, respectively). Escherichia coli was most commonly isolated (53.9 per cent) and affected female dogs, older dogs and neutered dogs more. There was an increase in the antimicrobial resistance of Enterococcus faecalis and Pseudomonas Aeruginosa, and a decrease in the effectiveness of enrofloxacin, cephalexin and oxytetracycline. The prevalence of urinary bacterial isolates is described for a large group of dogs. Monitoring changes in antimicrobial efficacy and microbial resistance guides the empirical use of antimicrobials for the treatment of urinary tract infection and helps formulate strategic plans to limit drug resistance.

Effect of dexamethasone or synthetic ACTH administration on endogenous ACTH concentrations in healthy dogs

To determine the effects of dexamethasone or synthetic ACTH administration on endogenous ACTH concentrations in healthy dogs. 10 healthy neutered dogs. Each dog received dexamethasone (0.01 mg/kg), synthetic ACTH (5 μg/kg), or saline (0.9% NaCl) solution (0.5 mL) IV at intervals of ≥ 30 days. Plasma endogenous ACTH concentrations were measured before (baseline; time 0) and 1, 8, 12, and 24 hours after drug administration; serum cortisol concentrations were measured before and 1 hour after synthetic ACTH and saline solution administration and 8 hours after dexamethasone administration. Analysis of serum cortisol concentrations confirmed effects of drug administration. Dexamethasone significantly decreased the endogenous ACTH concentration from the baseline value at both 8 and 12 hours. Synthetic ACTH administration significantly decreased the endogenous ACTH concentration from the baseline value at 8 hours. Saline solution administration had no significant effect on endogenous ACTH concentration. Dexamethasone and synthetic ACTH administered IV at doses used routinely during testing for hyperadrenocorticism caused significant but transient reductions of endogenous ACTH concentrations in healthy dogs. Thus, a 2-hour washout period following ACTH stimulation testing before collection of samples for measurement of the endogenous ACTH concentration may be insufficient. Although this effect has not been verified in dogs with hyperadrenocorticism, these data suggested that samples for measurement of endogenous ACTH concentrations should be obtained before or > 8 hours after initiation of an ACTH stimulation test or before or > 12 hours after the start of a low-dose dexamethasone suppression test.

Farmacocinética do propofol em nanoemulsão em cães

O propofol em nanoemulsão é uma nova formulação constituída por sistemas nanoemulsionados, caracterizado pela ausência do veículo lipídico. A modificação do veículo pode acarretar alterações farmacocinéticas, resultando em diferentes taxas de distribuição e excreção do propofol. O objetivo deste estudo foi avaliar a farmacocinética de uma nova formulação de propofol em nanoemulsão do tipo óleo em água, comparando com a formulação tradicional em emulsão lipídica. Foram utilizadas seis cadelas sem raça definida, castradas (10,7±1,5kg), em estudo aleatório e de autocontrole, que receberam as duas formulações de propofol com intervalo de 30 dias entre os tratamentos, sendo administrada uma dose bolus de 8mg kg-1, seguida de infusão contínua por 60 minutos na taxa de 0,4mg kg-1 min-1. Amostras de sangue arterial foram colhidas momentos antes da indução (0), 2, 5, 10, 15, 30 e 60 minutos após a dose bolus e após o término da infusão nos tempos 5, 10, 15, 30, 60 e 90 minutos e 2, 3, 4, 6, 10 e 24 horas. Não foram encontradas diferenças significativas entre os parâmetros farmacocinéticos de volume de distribuição, clearance, constante de eliminação, meia-vida e constantes de distribuição, demonstrando que o propofol em nanoemulsão não apresenta alteração farmacocinética em relação à formulação tradicional.

Age, sex and reproductive status affect boldness in dogs

Boldness in dogs is believed to be one end of the shy–bold axis, representing a super-trait. Several personality traits fall under the influence of this super-trait. Previous studies have found that boldness is affected by breed and breed groups, influences performance in sporting dogs, and is affected in some cases by the sex of the dogs. This study investigated the effects of dog age, sex and reproductive status on boldness in dogs by way of a dog personality survey circulated amongst Australian dog owners.Age had a significant effect on boldness (F=4.476; DF=16,758; P<0.001), with boldness decreasing with age in years. Males were bolder than females (F=19.219; DF=1,758; P<0.001) and entire dogs were bolder than neutered dogs (F=4.330; DF=1,758; P<0.038). The study indicates how behaviour may change in adult dogs as they age and adds to the literature on how sex and reproductive status may affect personality in dogs.

Effects of dietary glucose supplementation on the fasted plasma metabolome in cats and dogs

The study objective was to evaluate nutritional metabolomics in support of companion animal nutrition. The specific purpose was to identify metabolites that differed significantly (q-value < 0.05) in the 23 h fasted plasma metabolome of healthy adult female neutered cats (n = 14) and dogs (n = 14) following 2 weeks adaptation to a single batch of diet, nutritionally complete for both species, with and without dietary glucose supplementation (3.85 % w/w). The study consisted of a two-way, crossover design with samples from individual animals on days 14, 16 and 18 of each diet. Metabolic profiling consistently identified 219 metabolites from cats and 216 metabolites from dogs. Fasted plasma glucose did not change significantly with diet in either species whilst 41 % of cat and 20 % of dog metabolites did change significantly. In general, the two species responded similarly and provided data interpretable within the context of insulin-regulated responses to glucose, for example decreased fatty acid oxidation, increased uptake of branched chain amino acids into muscle, and in cats, decreased glucogenic amino acid catabolism. Other responses, such as increased 1 carbon pool intermediates in cats, were consistent with known nutritional differences between cats and dogs and interpretable within the context of energy metabolism. Data also indicated inter-individual variability and diet-dependent changes in digestion and absorption, providing insights for future study designs. In this proof-of-principle study it was concluded that metabolomics can provide data interpretable to a well-characterised area of nutrition and metabolism and also provide novel insights into metabolic adaptations with relevance to companion animal nutrition.

Neutering Dogs: Effects on Joint Disorders and Cancers in Golden Retrievers

In contrast to European countries, the overwhelming majority of dogs in the U.S. are neutered (including spaying), usually done before one year of age. Given the importance of gonadal hormones in growth and development, this cultural contrast invites an analysis of the multiple organ systems that may be adversely affected by neutering. Using a single breed-specific dataset, the objective was to examine the variables of gender and age at the time of neutering versus leaving dogs gonadally intact, on all diseases occurring with sufficient frequency for statistical analyses. Given its popularity and vulnerability to various cancers and joint disorders, the Golden Retriever was chosen for this study. Veterinary hospital records of 759 client-owned, intact and neutered female and male dogs, 1–8 years old, were examined for diagnoses of hip dysplasia (HD), cranial cruciate ligament tear (CCL), lymphosarcoma (LSA), hemangiosarcoma (HSA), and mast cell tumor (MCT). Patients were classified as intact, or neutered early (<12 mo) or late (≥12 mo). Statistical analyses involved survival analyses and incidence rate comparisons. Outcomes at the 5 percent level of significance are reported. Of early-neutered males, 10 percent were diagnosed with HD, double the occurrence in intact males. There were no cases of CCL diagnosed in intact males or females, but in early-neutered males and females the occurrences were 5 percent and 8 percent, respectively. Almost 10 percent of early-neutered males were diagnosed with LSA, 3 times more than intact males. The percentage of HSA cases in late-neutered females (about 8 percent) was 4 times more than intact and early-neutered females. There were no cases of MCT in intact females, but the occurrence was nearly 6 percent in late-neutered females. The results have health implications for Golden Retriever companion and service dogs, and for oncologists using dogs as models of cancers that occur in humans.