Embryo losses in sheep during short-term nutritional supplementation

Area of Science:

• Animal Science
• Reproductive Biology
• Nutritional Physiology

Background:

• Nutritional supplementation can influence reproductive outcomes in livestock.
• Understanding the impact of specific feedstuffs like lupin grain on ewe reproduction is crucial for optimizing flock performance.

Purpose of the Study:

• To investigate the effects of lupin grain supplementation on progesterone concentrations and embryo losses in Merino ewes.
• To determine the impact of supplementation timing (pre-insemination vs. pre- and post-insemination) on reproductive hormones and embryo survival.

Main Methods:

• Merino ewes were divided into three groups: Control (no supplement), Lupin6 (supplemented 6 days pre-insemination), and Lupin6+15 (supplemented 6 days pre- to 15 days post-insemination).
• Progesterone, insulin, IGF-I, and leptin concentrations were monitored throughout early pregnancy.
• Embryo losses were assessed at different stages (Days 10-17 and Days 17-30 post-insemination).

Main Results:

• No significant differences in progesterone concentrations were observed between groups during the first 17 days of pregnancy.
• Embryo losses were lower in the Lupin6+15 group during Days 10-17 but higher during Days 17-30 compared to controls.
• Insulin and IGF-I concentrations increased in the Lupin6+15 group, while leptin concentrations decreased by Day 17.

Conclusions:

• Supplementation with lupin grain for 15 days post-mating enhanced early embryo survival in Merino ewes.
• This improvement was associated with elevated metabolic hormone levels (insulin, IGF-I) and potentially lower progesterone.
• The decrease in leptin concentrations observed later in the Lupin6+15 group may be linked to increased embryo mortality up to Day 30, suggesting a complex role for nutrition in late-stage embryo survival.