Maternal age and parity influence ultrasonographic measurements of fetal growth in Dutch Warmblood mares.

The research article observes how various factors, including the age and parity of Dutch Warmblood mares, influence the growth of the fetus as detected via ultrasound examinations. It implies that fetus growth in these horses in late gestation may require continuous measuring due to various influencing factors.

Study Objective and Method

• To understand the influence of different maternal factors on fetal growth, the researchers observed the development of fetuses in 32 Dutch Warmblood mares through regular fortnightly ultrasounds from the 100th day of gestation until giving birth. The mares ranged from 4 to 18 years in age and included seven first-time mothers.
• Various fetal measures like the eye orbit, skull, aorta, and heart rate were taken along the combined thickness of the uterus and placenta (CTUP) with the help of a portable ultrasound machine equipped with a 6 MHz linear and a 3.5 MHz curved array probe.

Observations and Findings

• During the 100th to 250th day of gestation, primiparous (first-time mothers) mares had thicker CTUP than multiparous mares (those that have given birth two or more times).
• After the 220th day, the maximum cross-sectional area of both the eye orbit and the skull was found to be larger in first-time mother mares compared to those mares who have previously given birth. However, the diameter remained unaffected by such divisions.
• The diameter of the fetal aorta was not affected by whether it was the mare’s first or subsequent pregnancy, but it was affected by the mare’s age. In mares that were 15 years old or more, the aorta diameter was smaller than in younger mares.
• Despite being influenced by the age and parity of the mares, the fluctuation in the size of the fetus during late gestation is considerable. Consequently, consecutive measurements may be necessary to accurately ascertain any abnormal development.