Preliminary Ultrasonographic Study of Healthy California Sea Lion (Zalophus californianus) Pregnancy and Fetal Development
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Jungle Park, Urb. Las Aguilas del Teide s/n, 38640 Arona, Tenerife, Canary Islands, Spain
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Loro Parque Fundación, Av. Loro Parque, s/n, 38400 Puerto de la Cruz, Tenerife, Canary Islands, Spain
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DISPeA Department, University of Urbino, C. Bo, Via Piazza della Repubblica, 13, 61029 Urbino, Italy
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Ambulatorio Veterinario Saviano-Larocca, 41042 Spezzano, Italy
*
Author to whom correspondence should be addressed.
Animals 2024, 14(9), 1384; https://doi.org/10.3390/ani14091384
Submission received: 19 March 2024
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Revised: 29 April 2024
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Accepted: 2 May 2024
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Published: 5 May 2024
(This article belongs to the Special Issue The Mediterranean Monk Seal and Other Endangered Marine Mammals. From Past to Future: Perspectives on Ecology, Biology, Monitoring, and Conservation)
Simple Summary
Ultrasonography has been widely used in the field of veterinary medicine as a diagnostic tool for all kinds of animals, especially as a method of early diagnoses of pregnancy. Ultrasonography plays an important role in marine mammal preventative medicine and it is useful to monitor the estrus cycle, abnormal pregnancies, embryonic resorption, or fetal abortion. A large amount of studies is available on normal appearance during the fetal development in most domestic species; however, there is a lack of data to facilitate optimum diagnostic possibilities in marine mammals. This study provides additional information on maternal ultrasonographic monitoring and fetus wellness in California sea lion (Zalophus californianus) species, describing for the first time ultrasonographic findings from the ovulation up to the birth and the embryo and fetal organogenesis.
Abstract
Reproductive success is an important aspect of marine mammals’ population health, as it is an indicator of the trajectory for the population into the future. The aim of this study is to provide additional relevant data on fetus–maternal ultrasonographic monitoring in sea lion species, in order to evaluate possible fetal distress or abnormalities. From 2018 to 2023, serial ultrasonographic scans of two healthy California sea lion females (16 ± 4 years old), kept under human care, were performed over the course of two pregnancies for each female. Animals were monitored from the ovulation to the delivery. Ultrasonography was performed weekly, and, during the last month, daily images were recorded using Logiq Versana Active, General Electric, with a 2–5 MHz curvilinear transducer, and Logiq V2, General Electric, with a 2–5 MHz curvilinear transducer. Right and left lateral recumbencies have been used during the examination. To the author’s knowledge, this is the first study describing in detail the sea lion organogenesis and their correlation with the stage of pregnancy.
