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Interpretive Summary: Impacts of intermittent maternofetal oxygenation on IUGR lambs

By: Anne Kamiya, MS

Intrauterine growth restriction (IUGR) caused by placental insufficiency is highly problematic because fetal hypoxemia leads to low birthweight and impaired growth in livestock. Ways to counter the negative impacts of placental insufficiency are therefore necessary to increase the productivity and health of IUGR-born livestock. 

In this recent Journal of Animal Science study, researchers evaluated how intermittent maternofetal oxygenation during late gestation impacted the metabolism, health, and growth of IUGR lambs. Intermittent and late gestation were defined as 8 hours of oxygen daily for the last two weeks of gestation. Ewes in this study were prompted to produce either control lambs (thermoneutral conditions) or IUGR lambs (induced via the maternal hyperthermia model). The IUGR lambs received either no maternofetal oxygenation during late gestation or oxygen supplementation via maternal oxygen insufflation. 

Results indicated that the IUGR lambs that were not given maternofetal oxygen weighed less and grew slower than both the oxygenated IUGR lambs and the control lambs. Oxygenated IUGR lambs also had increased birthweight, growth, and muscle mass compared to the unoxygenated IUGR lambs. Glucose-stimulated insulin secretion (GSIS) and hindlimb hyperinsulinemic-euglycemic clamp (HEC) was minimally different between IUGR lambs regardless of oxygenation status, although there was some metabolic improvement with oxygenation, but it was not comparable to the control lambs.

Overall, the results of this study suggest that maternofetal oxygenation during late gestation benefits the growth and health of IUGR lambs. The authors note that skeletal muscle β2 adrenoceptor content was unaffected by oxygenation suggesting a different mechanism behind these noted improvements. More studies into the mechanisms behind the improved outcomes of IUGR livestock given intermittent maternofetal oxygenation during late gestation are warranted. 

The original article, Intermittent maternofetal oxygenation during late gestation improved birthweight, neonatal growth, body symmetry, and muscle metabolism in intrauterine growth-restricted lambs, is viewable in the Journal of Animal Science.