Short term protein supplementation during a long interval prostaglandin-based protocol for timed AI in sheep

Area of Science:

• Reproductive biology
• Animal science
• Nutritional science

Background:

• Timed artificial insemination (TAI) protocols are crucial for efficient sheep breeding.
• Prostaglandin-based synchronization protocols, like the PG15 method, are widely used.
• Optimizing reproductive performance in ewes remains a key objective in sheep production.

Purpose of the Study:

• To assess the impact of short-term protein supplementation on reproductive parameters in sheep.
• To compare the efficacy of spontaneous estrus (SE) versus a prostaglandin-based protocol (PG15) for TAI.
• To evaluate the interaction between estrus type and protein supplementation on ewe fertility.

Main Methods:

• A 2x2 factorial design was employed with 437 multiparous Merino ewes.
• Treatments included spontaneous estrus (SE) or PG15 synchronization, with or without protein supplementation (+FF).
• Reproductive outcomes such as ovulation rate, conception, fertility, and fecundity were evaluated.

Main Results:

• The PG15 protocol resulted in lower ovulation rates, conception, fertility, and fecundity compared to SE.
• Protein supplementation significantly increased ovulation rate, prolificacy, and fecundity in both SE and PG15 groups.
• In PG15 ewes, protein supplementation improved reproductive parameters to levels comparable to supplemented SE ewes, though pregnancy rates did not differ.

Conclusions:

• Short-term protein supplementation effectively enhances reproductive performance in ewes synchronized with the PG15 protocol.
• Supplementation can mitigate the negative effects of the PG15 protocol, bringing its reproductive efficiency closer to that of spontaneous estrus.
• This nutritional strategy offers a practical approach to improve TAI success in sheep management.