The theme of ultrasound and pregnancy over the last few articles is continued this week as the paper published by Yotov SA in 2012 is discussed - Ultrasound Diagnostics of Late Embryonic and Foetal Death in Three Sheep Breeds, J. Vet Adv. 2(3) pp120-125. For those wishing to read the article in full, it can be accessed by clicking here.

This paper aimed to utilise ultrasound imaging as a tool by which to detect either embryo or foetal death occurring during pregnancy in sheep between days 20-50 of gestation. These studies were carried out using 3 different breeds, each one associated with a different ‘function’ – sheep primarily used for wool (Trakia merino), milk (Pleven blackhead) and meat (Ile de France) and the establishment of pregnancy was carried out transabdominally, and then transrectally where results were not definitive. The results made for interesting reading, and revealed that whether a sheep was pregnant for the first time or was experiencing a subsequent pregnancy made a difference when calculating the incidence of embryo/foetal death. In both the sheep used for wool and milk, death was higher in those animals that had been pregnant previously. The same trend was also seen with the sheep used for meat, although here results were not considered statistically significant (the method by which scientists deduce whether their results are ‘true phenomena’ or not).  Therefore, one conclusion that can be drawn from this paper is that whether or not a sheep is experiencing pregnancy for the first time can affect the likelihood of pregnancy loss occurring. One explanation given in this paper to explain these results is due to an association with the presence of microbes in the uterus that may occur as a result of, for example, prior pregnancies.

In addition, this study also revealed that the period during pregnancy could also affect whether loss was likely to happen or not – briefly, the further along gestation the sheep was, the less likely (late) death was to occur. One further revelation stemming from this study relates to the application of ultrasound itself, with day 40 of gestation being deemed the best with respect to being able to confirm pregnancy/embryonic loss using a predominantly transabdominal approach. It may therefore be a sensible precaution to closely monitor pregnant sheep early on during pregnancy to ensure that the risk of loss is reduced as much as possible.

In sum, ultrasound could be a very useful application to help detect and maintain pregnancy in sheep throughout the duration. To see the range of ultrasound equipment we stock suitable for use with sheep, please click here.