Relationship between thyroid function and sex hormones in female German shepherd dogs.

BACKGROUND: Several variables influence the serum concentration of thyroid hormones in dogs, including breed, age, drugs, and concurrent diseases. However, data regarding the interaction between thyroid function and the estrous stage of female dogs are limited. HYPOTHESIS: Estrous stage may influence thyroid function in German Shepherd dogs. METHODS: Longitudinal, observational, non-randomized cohort study. The dogs were monitored during the complete estrous cycle, and different stages were determined by vaginal cytology. Two blood samples were collected at the beginning and end of each stage to analyze the following: total thyroxine (TT4), free thyroxine (fT4), total triiodothyronine (TT3), free triiodothyronine (fT3), canine thyrotropin (cTSH), progesterone, 17-ß-estradiol, triglycerides, and cholesterol concentrations. Hematological and biochemical evaluations were performed at the beginning and end of the study period. ANIMALS: Seventeen German Shepherds were included, of which 7 were bred during the study period. One dog was excluded for estrus interruption and another for suspected hypothyroidism. RESULTS: Serum concentrations of T4, fT4, and fT3 were negatively correlated with age. Total thyroxine demonstrated significant changes in serum concentrations between estrous stages, with higher concentrations in estrus and diestrus. Total thyroxine concentrations were positively correlated with progesterone concentrations and negatively correlated with 17-ß-estradiol concentrations. Free thyroxine did not show significant variations but was positively correlated with progesterone concentrations. Canine TSH concentrations were positively correlated with 17-ß-estradiol concentrations. No significant differences in thyroid hormones and cTSH concentrations were observed between diestrus during pregnancy and pseudopregnancy. CONCLUSIONS: Different stages of estrus can influence the measurement of TT4 in female dogs.

Neonatal-Maternal Bodyweight Ratio at Birth: An Indicator for First-Week Survival Prognosis in Canine Newborns.

Objectives. In dogs, neonatal bodyweight (NBW) varies at birth. Size-specific reference values for NBW are essential to correctly manage newborns. The present study aimed to define a new tool to evaluate NBW that could be routinely applied in canine neonatology, promptly identifying puppies requiring more care. Methods. The records of 89 litters were retrospectively evaluated. Data were grouped according to maternal bodyweight (MBW) in five categories: toy (≤5 kg), small (5.1-9.9 kg), medium (10-24.9 kg), large (25-39.9 kg), and giant (≥40 kg) dogs. At birth, the NBW of 412 puppies, alongside their litter size (LS) and gender (G), were recorded. Neonatal mortality within the first week was considered. The influence of MBW, LS, and G on NBW and the effect of NBW on the 1-week outcome were evaluated using ANOVA (p < 0.05). The ratio between NBW and MBW expressed as a percentage (N-MBW%), was assessed for each puppy. Through Receiver-Operating Characteristic (ROC) curves, N-MBW% thresholds between puppies alive or dead at one week of age were calculated in each group. Results. The LS was different among groups, except for small vs. medium dogs. In small litters, N-MBW% was lower in medium-, large- and giant-sized dogs than in toy and small dogs. In medium and large litters, N-MBW% differed among the five groups. Male and female N-MBW% differed among the five groups. Only in large and giant sizes did LS affect N-MBW%, which was lower in a large LS. The N-MBW% was higher in healthy puppies than in those who died within one week. The ROC-derived N-MBW% thresholds were as follows: 4.5% in toy-, 3.2% in small-, 1.5% in medium-, 1.2% in large-, and 1% in giant dogs. Clinical significance. The ROC-derived N-MBW% thresholds can be used to cautiously identify puppies at increased risk for one-week mortality and may be helpful in clinical practice, representing a suitable parameter to give a prognosis on 1-week survival immediately at birth.

Discrepancy Between In-clinic and Haemagglutination-Inhibition Tests in Detecting Maternally-Derived Antibodies Against Canine Parvovirus in Puppies.

Canine parvovirus (CPV) is one of the most common causes of mortality in puppies worldwide. Protection against CPV infection is based on vaccination, but maternally-derived antibodies (MDA) can interfere with vaccination. The aim of this study was to evaluate the applicability of an in-clinic ELISA test to assess the CPV MDA in unvaccinated puppies and CPV antibodies in bitches, comparing the results with the gold standard haemagglutination inhibition (HI) test. Serum samples of 136 unvaccinated puppies were tested, along with sera of 16 vaccinated bitches. Five unvaccinated puppies were retested after vaccination. Both assays showed that the 16 vaccinated bitches had protective antibody levels against CPV. Conversely, significant discrepancies were observed for the MDA titers in unvaccinated puppies. Protective MDA titers were observed in 91.9% puppies using HI and in 40.4% by the in-clinic ELISA test, and only the latter one showed a decrease of MDA titers and percentages of protected puppies after the first weeks of age. Vaccination of five puppies with high HI and low in-clinic ELISA MDA titers resulted in seroconversion. Our results confirm the reliability of the in-clinic ELISA test in determining protective antibodies against CPV in adult dogs. Our findings also suggest that the in-clinic ELISA test kit may also be a useful tool to detect and quantify CPV MDA, thus allowing prediction of the best time to vaccinate puppies and reduction of the rate of vaccination failures due to interference by maternally-derived antibodies.

Canine fertility: The consequences of selection for special traits.

Pedigree dogs and cats are bred aiming to conform breed standards with very poor consideration for breeding stock fertility. At the same time, the genetic asset underlining reproductive traits could be effectively analysed like in other species under selection. The definition of selection targets is very important in breeding protocols determination. The aim of the present work is to present an overview of the different correlations between reproduction and genetics, starting from selection procedure and inbreeding coefficient moving to genomic and the application of SNPs and GWAS on population study and identification of genes involved in phenotypical variation of reproductive traits in dogs. Particular relevance has been given to the concept of inbreeding which effects on canine reproduction have been presented. The use of genomic information in inbreeding coefficient calculation can be considered an improved effective procedure in the evaluation of the genetic variability loss in canine population and its negative effects on reproductive traits.

Mucopolysaccharidosis VI in cats - clarification regarding genetic testing.

The release of new DNA-based diagnostic tools has increased tremendously in companion animals. Over 70 different DNA variants are now known for the cat, including DNA variants in disease-associated genes and genes causing aesthetically interesting traits. The impact genetic tests have on animal breeding and health management is significant because of the ability to control the breeding of domestic cats, especially breed cats. If used properly, genetic testing can prevent the production of diseased animals, causing the reduction of the frequency of the causal variant in the population, and, potentially, the eventual eradication of the disease. However, testing of some identified DNA variants may be unwarranted and cause undo strife within the cat breeding community and unnecessary reduction of gene pools and availability of breeding animals. Testing for mucopolysaccharidosis Type VI (MPS VI) in cats, specifically the genetic testing of the L476P (c.1427T>C) and the D520N (c.1558G>A) variants in arylsulfatase B (ARSB), has come under scrutiny. No health problems are associated with the D520N (c.1558G>A) variant, however, breeders that obtain positive results for this variant are speculating as to possible correlation with health concerns. Birman cats already have a markedly reduced gene pool and have a high frequency of the MPS VI D520N variant. Further reduction of the gene pool by eliminating cats that are heterozygous or homozygous for only the MPS VI D520N variant could lead to more inbreeding depression effects on the breed population. Herein is debated the genetic testing of the MPS VI D520N variant in cats. Surveys from different laboratories suggest the L476P (c.1427T>C) disease-associated variant should be monitored in the cat breed populations, particularly breeds with Siamese derivations and outcrosses. However, the D520N has no evidence of association with disease in cats and testing is not recommended in the absence of L476P genotyping. Selection against the D520N is not warranted in cat populations. More rigorous guidelines may be required to support the genetic testing of DNA variants in all animal species.

Evaluation of a ketamine-propofol drug combination with or without dexmedetomidine for intravenous anesthesia in cats undergoing ovariectomy.

OBJECTIVE: To evaluate the use of a ketamine-propofol combination, with or without dexmedetomidine, in cats undergoing ovariectomy and to assess Heinz body formation following administration of these drugs. DESIGN: Randomized clinical trial. ANIMALS: 15 client-owned female cats. PROCEDURES: Anesthesia was induced with a ketamine (2.0 mg/kg [0.91 mg/lb])-propofol (2.0 mg/kg) combination with (n = 7) or without (8) dexmedetomidine (0.003 mg/kg [0.0013 mg/lb]) and was maintained via continuous IV infusion of a 1:1 ketamine-propofol combination (administration rate for each drug, 10.0 mg/kg/h [4.54 mg/lb/h]). Cats underwent ovariectomy; duration of infusion was 25 minutes. Physiologic variables were measured at predetermined time points. Heinz bodies were quantified via examination of blood smears. Numeric scales were used to assess quality of recovery, degree of sedation, and signs of pain after surgery. RESULTS: The ketamine-propofol group had a significantly higher mean heart rate at several time points during drug infusion, a significantly shorter time from the end of infusion to extubation (7 vs 29 minutes), and significantly lower sedation scores for the first hour after surgery than did the ketamine-propofol-dexmedetomidine group. Other variables were similar between groups; recovery was smooth, and anesthesia and postoperative analgesia were deemed adequate for all cats. The number of RBCs with Heinz bodies was not increased after surgery, compared with values immediately after anesthetic induction. CONCLUSIONS AND CLINICAL RELEVANCE: Total IV anesthesia with a ketamine-propofol combination, with or without dexmedetomidine, appeared to be effective in healthy cats. These short-term infusions produced smooth recovery and adequate analgesia during the postoperative period.

Pharmacokinetics and efficacy of intravenous and extradural tramadol in dogs.

Tramadol is a synthetic opioid agonist used extensively in human and, to a lesser extent, veterinary medicine throughout the world. The clinical efficacy and pharmacokinetic profile of intravenous (i.v.) and extradural (e.d.) tramadol (2 mg/kg) and its o-desmethyl metabolite were studied in dogs undergoing tibial plateau levelling osteotomy (TPLO). Intra-operative cardiorespiratory variables were monitored and post-operative pain was assessed using the short form of the Glasgow Composite Pain Scale. A rapid (<5 min) and effective production of o-desmethyl tramadol was recorded. The pharmacokinetic profile was similar for tramadol and its metabolite irrespective of the route of administration. E.d. tramadol provided sufficient intra- and post-operative analgesia without significant clinical side-effects, but the post-operative analgesia was comparable to that following i.v. administration and the e.d. route could therefore not be considered a practical alternative to the i.v. route.