Comparison of three different fetometric formulas of ICC and BP for calculating the parturition date in a population of German Shepherd

- We evaluate the suitability of three different formulas of ICC and BP to predict the parturition date in population of German Shepherds.
- Comparing the clinical accuracy of the three formulas, the authors demonstrated that the Luvoni and Grioni (2000) formula for ICC can be effectively used in the German Shepherd.
- The evaluation of BP formulas proves the successful usage of the Groppetti et al. (2015) formula to determine the date of birth by measuring scull bone structures (p < 0.05).
- The statistical analysis of regression lines confirmed the higher predictability of Groppetti et al. (2015) and Luvoni and Grioni (2000) formulas, than those of Milani et al. (2013).

The aim of this study was to evaluate the suitability of three different formulas to predict the parturition date in German Shepherds, using the ultrasonographic fetometry method involving inner chorionic cavity diameter (ICC) and biparietal diameter (BP) measurements in the same population of a single breed. Overall, 53 ICC and 42 BP measurements were taken on 34 bitches. The measured values were substituted into breed-specific formulas for the German Shepherd as well as non-specific formulas for medium-sized bitches. Comparisons of clinical accuracy and statistical analyses of regression lines were performed to test the compatibility of the formulas used. We confirmed the similarity of our clinical results to outcomes obtained using the one breed-specific (Groppetti et al. 2015) and non-specific fetometry models (Luvoni and Grioni 2000), whereas another breed-specific formula (Milani et al. 2013) showed rather low accuracy. Comparing the clinical accuracy of the three formulas, the authors demonstrated that the Luvoni and Grioni (2000) formula for ICC dedicated to medium-sized dogs can also be effectively used in the German Shepherd, even with better results than breed-specific formulas by Groppetti et al. (2015). By contrast, the evaluation of BP formulas proves the successful usage of the Groppetti et al. (2015) formula to determine the date of birth by measuring scull bone structures (p < 0.05). The statistical analysis of regression lines were in agreement with the clinical results and confirmed the higher predictability of Groppetti et al. (2015) and Luvoni and Grioni (2000) formulas, than those of Milani et al. (2013).