Prediction of Parturition Time in Queens using Radiography and Ultrasonography

Abstract

This study investigated the prediction of parturition in queens, as well as the effects of the queens' age and weight and the litter size on the accuracy of the prediction. A prospective study was performed in 24 purebred queens of 11 different breeds, all in normal body condition, using radiographic and ultrasonographic measurements of foetal femoral length (FL) and biparietal diameter (BPD) of fœtal skull that apply to different breeds. Pregnant queens with aborted or malformed foetuses were excluded. The examinations were performed up to three times during the second half of pregnancy; litter size was obtained with radiography, and FL and BPD measurements were taken of each foetus using both radiography and ultrasonography. The maximal FL and the transversal BPD were recorded for each foetus. Radiography showed the number of foetuses accurately but did not allow accurate prediction of time of parturition. However, ultrasonography did establish the best predictive model according to the data with the FL. This model corresponded to the formula Y = 37.864 - 0.193 × FL + 1.227 × W - 0.615 × LS - 0.832 × A using the FL (10(-1) mm), litter size (LS, number of foetuses per queen) and maternal parameters (weight (W, kg) and age (A, years)). Time to parturition correlated positively with the queen's weight and negatively with her age (P < 0.01). The ultrasonographic FL associated with pregnancy and maternal factors appeared to be an accurate model to predict parturition.

Ultrasonographic and progesterone changes during Days 21 to 63 of pregnancy in queens

“…In Brito et al study like in our work, GS and fetal measurements increased as gestational aged advanced. The linear increase in biparietal diameter during pregnancy founded by Gatel et al [15] is in agreement with our results in which the same parameter increases with the days after mating.…”

“…Hence, ultrasonographic measurements could be useful to estimate gestational age in almost every breed of queen and to confirm that measurements are within the expected range to a given day of gestation. Gatel et al [15] observed that the time to parturition increased more the queen weighed before mating, suggesting that the queens' size influenced gestational length. In addition, the time to parturition was shorter when the queen was older [15].…”

“…Gatel et al [15] observed that the time to parturition increased more the queen weighed before mating, suggesting that the queens' size influenced gestational length. In addition, the time to parturition was shorter when the queen was older [15]. In contrast, in our study, no significant relationship between the queen's weight and age and gestation length because the animals used in our work had similar weight and age.…”

“…More recently, Brito et al [18] observed that all GS and fetal measurements increased as gestational age advanced [18]. Similarly, Gatel et al [15] found that biparietal diameter and femoral length increase linearly during pregnancy [15].…”

“…Although several researchers have done many ultrasonography studies on queen pregnancy, to our knowledge, there are no thorough studies during the last two-thirds of gestation [10,[12][13][14][15][16][17][18]. In 1986, Davidson et al [10] described a considerable variability in the diameters of the gestational sacs (GSs) and the lengths of fetal poles among individual fetuses within a litter, as well as between litters [10].…”