Doppler and Micro-V ultrasonography to evaluate placental insufficiency in sheep subjected to insolation

• Grant number: 25/04213-6
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: May 01, 2025
• End date: April 30, 2026
• Field of knowledge: Agronomical Sciences - Veterinary Medicine
• Principal Investigator: Marcus Antônio Rossi Feliciano
• Grantee: Clara César Pintor Ferreira
• Host Institution: Faculdade de Zootecnia e Engenharia de Alimentos (FZEA). Universidade de São Paulo (USP). Pirassununga , SP, Brazil

Abstract

The increase in temperature is the climatic event with the greatest influence on the animal's physical environment, responsible for causing heat stress, which in turn leads to a reduction in food consumption and an increase in water consumption, resulting in a drop in the animals' productiveand reproductive performance. On the reproductive side, placental vascularization is compromised,making the transfer of nutrients to the fetus deficient. Conditions such as hypoxia, malnutrition, delayed fetal development, shorter gestation periods and lower birth weights are all consequences of this problem. In view of this scenario of increasingly intense climate change and the fact that placental disorders are subtle conditions that are usually diagnosed late, this study was designed to investigate non-invasive diagnostic modalities that are easy to use and provide important information for monitoring and early detection of gestational abnormalities in pregnant sheep. We propose a comparative investigation of B-mode ultrasound, Doppler ultrasound and Micro-V ultrasound (microvascular ultrasound). Fourteen Santa Ines ewes will be used, divided into two groups (control and treatment). Estrus synchronization and natural mating will be carried out, followed by pregnancy diagnosis on day 30 after mating. From day 70 until day 120 of gestation, the ewes in the treatment group will be placed in an unshaded paddock to induce placental insufficiency due to heat stress. Ultrasound scans will be carried out on days 70, 80, 100, 120 and 135. We hope to demonstrate that the assessment of low-velocity blood flows and placental microvascularization will be facilitated by the use of microvascular ultrasound and that, in this way, even discrete placental alterations can be detected.