Assessment of fetal development during mid and late term pregnancies by standard B-Mode ultrasonography in Shetland ponies.

This research investigates the use of ultrasonography to monitor fetal development in mid and late-term pregnancies in Shetland ponies. The study aimed to gather reference data on biometric parameters and physiological changes for future clinical and research use.

Study Background

• The study articulates the established use of transrectal and transabdominal ultrasonography for monitoring pregnancies across various animal species.
• Growth charts using several bio-morphometric parameters are available for different animals and horse breeds, but not for small horse breeds like Shetland ponies.
• Such growth charts help in estimating the gestational period and time before parturition or the act of giving birth.

Study Aim

• The main aim of the study was to apply fetal biometric assessments to Shetland mares during mid and late-term pregnancies.
• The research also aimed to provide a detailed description of physiological fetal development, thereby producing reference data for future research and clinical application.

Data Collection and Parameters

• The study followed five Shetland mares from the 101st day of their pregnancy onwards.
• Various fetal biometric parameters were observed, including eye and aortic diameter, stomach length and width, combined rib and intercostal distance (CRID), and several heart morphology parameters.
• The researchers also recorded fetal activity and organ development, observing changes in differentiation and echogenicity (ability to produce an ultrasound echo).

Main Findings

• The research determined that fetal CRID was the best predictor for gestational age, providing a reliable assessment within ± 13.6 days.
• It also found that the fetal aortic diameter was the most accurate tool for predicting the number of days until parturition, within ± 16.2 days.

Significance

• The study provides vital data and insights for future research and clinical practice concerning fetal development in Shetland ponies.
• It offers an opportunity for more accurate prediction and monitoring of the gestational period and time before birth in ponies, contributing to the welfare and care of pregnant Shetland mares.