Supplementing treated anoestrous dairy cows with progesterone does not increase conception rates

Area of Science:

• Veterinary Medicine
• Animal Reproduction
• Endocrinology

Background:

• Anoestrous dairy cows present a challenge to reproductive efficiency.
• Hormonal treatments are used to induce oestrus and ovulation in these animals.
• The role of extended progesterone support post-insemination requires further investigation.

Purpose of the Study:

• To evaluate the efficacy of supplementary progesterone treatment following insemination in anoestrous dairy cows.
• To determine if additional progesterone improves conception rates in cows induced into oestrus.

Main Methods:

• Anoestrous dairy cows (n=1178) were treated with progesterone and oestradiol benzoate (ODB) to induce oestrus.
• Cows observed in oestrus were inseminated and randomly assigned to receive either supplementary progesterone (P4+) or no further treatment (Control).
• Conception rates were assessed, and ovulation rates were determined in a subset via milk progesterone analysis.

Main Results:

• First insemination conception rates were comparable between the P4+ (40.3%) and Control (37.2%) groups.
• Ovulation occurred in 78.6% of cows assessed for progesterone levels.
• Among ovulating cows, conception rates remained similar between the P4+ (46.8%) and Control (43.5%) groups.

Conclusions:

• Progesterone supplementation with CIDR inserts following insemination did not enhance conception rates in anoestrous dairy cows.
• The findings suggest that the initial hormonal protocol is sufficient for achieving comparable conception rates without additional luteal support.