Estimated date of delivery in Chihuahua breed bitches, based on embryo-fetal biometry, assessed by ultrasonography

Abstract

Due to the peculiarities of the reproductive cycle of the female dog, which makes it difficult to accurately ascertain the date of conception, it may be challenging to precisely estimate the gestational age in bitches. Using fetal measurements obtained by ultrasound, it is possible to estimate the gestational age in dogs; however, due to the differences in size of the various breeds, such estimates may have a significant standard deviation, which represents less accuracy when specifying the date of birth. The purpose of this study was to evaluate pregnant female Chihuahuas, establishing relations between the fetal dimensions measured by ultrasound and the remaining time until delivery. Using 13 pregnant female Chihuahuas, weekly ultrasound assessments and measurements were performed, of the inner chorionic cavity, cranial-caudal length, biparietal diameter, abdominal diameter and thoracic diameter. Such parameters were retroactively correlated to the date of delivery, and linear regressions were established between the gestational measurements and remaining days until delivery. The fetal measurement presenting the highest correlation (r = 0.99; P<0.0001) and reliability (R 2 = 0.98, P<0.0001) with the probable date of delivery was the biparietal diameter, a measurement that can be easily and safely obtained and, when applying a specific formula (Y =-15.46X1 + 38.72), can accurately predict the date of delivery in Chihuahua female dogs.

Usefulness of Maternal and Fetal Parameters for the Prediction of Parturition Date in Dogs

“…OUD leads to inaccurate parturition timing, because of its not well defined measurement markers [ 56 ]. The measurement of ICC is done using the same scanning planes but measuring the distance between the inner sides of the chorionic wall from trophoblastic decidual reaction sites [ 14 , 57 ]. ICC is the most accurate extra-embryonic parameter in early pregnancies [ 11 , 12 ], and it is useful from days 17–18 to 37 after ovulation, with its best accuracy being on days 20–25 [ 6 , 11 , 51 , 55 ].…”

“…Because of differences in head and body morphology and gestation length between different breeds included in the same size class, specific breed formulas have been proposed in German Shepherd [ 62 , 63 ], Golden Retriever [ 64 ], Chihuahua [ 57 ] and Yorkshire breeds for the most commonly used parameters (ICC, BP, BD, CRL and DPTV) to increase the accuracy of parturition timing ( Table 5 ) [ 64 ]. Prediction tables have also been calculated for Maltese and Yorkshire breeds [ 55 ].…”

Comparison of two‐dimensional (2D) and three‐dimensional (3D) ultrasonography for gestational ageing in the early to mid‐pregnant bitch

“…Parturition is a critical event, and accurate prediction of the delivery date may allow better planning and management of whelping to decrease neonatal losses (Beccaglia et al., 2016 ). In the last decades, several studies had been published on gestational age determination and parturition date prediction in dogs, based on determination of ovulation by serum progesterone, on the first appearance of embryonic/foetal structures by ultrasonography or by abdominal radiograph, and on ultrasonographic measurements of extra‐foetal or foetal structures (Beccaglia et al., 2016 ; Cecchetto et al., 2017 ; Kutzler et al., 2003 ; Kutzler, Yeager, et al., 2003 ; Lopate, 2008 , 2018 ; Luvoni & Grioni, 2000 ; Nyland & Mattoon, 2002 ; Sananmuang et al., 2021 ; Siena & Milani, 2021 ; de Albuquerque Vieira et al., 2020 ; Yeager et al., 1992 ). Among the various parameters, ICC diameter was found to be a relatively accurate parameter in early to mid‐pregnant bitches (Beccaglia & Luvoni, 2012 ) and is extensively used in daily clinical practice.…”

“…Litter size does not seem to have an influence on accuracy of gestational ageing and parturition date prediction (Kutzler, Yeager, et al., 2003 ). On the other hand, body size and/or breed‐specific formulas or corrections to maternal body weight should be used to achieve the most accurate prediction of gestational age or parturition day (Cecchetto et al., 2017 ; Lopate, 2008 , 2018 ; Luvoni & Grioni, 2000 ; Sananmuang et al., 2021 ; Siena & Milani, 2021 ; Socha & Janowski, 2018 ; Son et al., 2001 ; de Albuquerque Vieira et al., 2020 ; Yeager et al., 1992 ).…”

Support vector regression algorithm modeling to predict the parturition date of small - to medium-sized dogs using maternal weight and fetal biparietal diameter

“…Accurate DBP predictions are crucial in these dog breeds to manage laboring support or elective cesarean deliveries. Ambiguous correction days for the DBP calculations (±1-2 days) [ 2 , 3 , 7 ] and breed-specific models [ 11 ] were suggested to improve the accuracy of the SLR model. However, these limitations highlight the need for an improved regression model to optimize the prediction of DBP.…”