Pregnancy is a crucial period in the life of cetaceans associated with growth and development of the fetus.¹ Using ultrasound to monitor pregnancies in cetaceans in captivity provides valuable data on the morphology, development and well-being of the fetus, as well as its soundings. For pregnancy in female bottlenose dolphins, these references require regular data collection.^2-4 The purpose of these studies was to identify pregnancy in female Black Sea bottlenose dolphins (Tursiops truncatus ponticus) using ultrasound and study the dynamics of the linear dimensions of the head and thorax of the fetus depending on its duration.

The studies we were able to determine pregnancy in females of the Black Sea bottlenose dolphins using ultrasound examination in the embryonic and fetal periods of its course, reveal dynamic differences in the size of the head and thorax of the fetus during the third through twelfth months of pregnancy. In the second month of pregnancy (Figure 1) in the cavity of the chorion, we noted hyperechoic structure of the embryo, then on the 3rd month (Figure 2), we find already fetus and placenta. Embryo becomes a fetus, having a similar configuration to the baby. As seen from Table 1, the diameter of the fetal head for the 3rd and 4th months yet somewhat larger diameter forming the rib cage at the 5th month, the situation changes and until the 11th month of the diameter of the chest ahead of the head diameter. Then, on the 12th month measurements of fetal body parts are compared again and reach almost 15 cm. Thus, it becomes clear that the use of the ultrasonic diagnosis for monitoring pregnancy in the Black Sea bottlenose is the most reliable in the first months of its occurrence. Although the presented data obtained during the examination of a relatively small number of pregnant animals, at this stage of knowledge, probably, they can be used as guidelines in the timing of pregnancy using ultrasound examination of the Black Sea dolphin females.

Table 1. Dynamics of changes in the dorsal-ventral dimensions of the head and thorax (X ± m, cm) of the fetus during pregnancy in females of Black Sea bottlenose dolphin

Legend: X - arithmetic average; m - standard error for the sample proportion; N - number of examined individuals; n - number of pregnancies studied. The significance of differences between this and the previous gestation: * - p < 0,05; **- p < 0,01; *** - p < 0,001.

Figure 1. Second month of gestation

Figure 2. Third month of gestation

Acknowledgments

The authors would like to express their gratitude for professional advice and practical assistance to the State Veterinary Administration of the Krasnodar Territory GBU "Veterinary Gelendzhik town," Munitsipalnomu health institution "City Hospital," Munitsipalnoe health facility "Maternity Hospital."

Literature Cited

1.  Robeck TR, Atkinson SKC, Brook F. Reproduction. In: Dierauf LA, Gulland FMD, editors. CRC Handbook of Marine Mammal Medicine. 2nd ed. Boca Raton, FL: CRC Press; 2001:193–226.

2.  Brook F, Bonn WV, Jensen ED. Ultrasonography. In: Dierauf LA, Gulland FMD, eds. CRC Handbook of Marine Mammal Medicine. 2nd ed. Boca Raton, FL: CRC Press; 2001:593–620.

3.  Taverne MAM. Applications of two-dimensional ultrasound in animal reproduction. Wien Tierärztl Monatsschr. 1991;78:341–345.

4.  Williamson P, Gales NJ, Lister S. Use of real-time B-mode ultrasound for pregnancy diagnosis and measurement of fetal growth rate in captive bottlenose dolphins (Tursiops truncatus). J Reprod Fertil. 1990;88:543–548.