SERUM LIPID PROFILE OF SPAYED AND NON-SPAYED FEMALE DOGS ASSOCIATED WITH THE BODY CONDITION SCORE

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-β-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-β-estradiol concentrations. Free thyroxine did not show significant variations but was positively correlated with progesterone concentrations. Canine TSH concentrations were positively correlated with 17-β-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.

Effect of Nutrition on the Morphometric Markers in Spayed Dogs

Obesity and overweight have been frequently observed in dogs in recent years as in humans. The compositions of fatty acids in the accumulated lipids in tissues of obese animals may have important roles in the process and mechanisms related to the onset of metabolic disorders. The purpose of this study was to evaluate the effects of a vegetarian diet, which contained a higher proportion of unsaturated fatty acids on individual morphometric parameters in spayed dogs. Seven mongrel dogs without ideal body condition scores (average: 7.42) were fed vegetarian dog kibbles and received the daily amount of energy calculated with the following formula: 130 kcal × weight (kg) 0.75. The animals were evaluated on days 0 and 60 in relation to the body measurements, such as: body weight, metabolic body weight, body fat percentage, nape, rib, tail base, chest, and abdomen, using a plicometer. Also determined were the body condition scores (scale from 1—thin to 9—obese), canine body mass index, and their waist circumference. These data were analysed by the Student’s t-test. The body measurement variation of body fat percentage, waist circumference, body condition score and thickness values of the abdomen differed significantly (P < 0.01).