Distribution and size of corpora lutea in dairy cows during puerperium

Abstract

During puerperium phase in cows, uterus goes through involution process, while ovaries restore supressed cyclicity as a result of gestation. After 10-20 days postpartum (PP) luteinizing hormone (LH) levels begin to raise and renewal of cyclicity after parturition is probably most important factor for cows to successfuly conceive again. Almost 95% of dairy cows should restore ovarian cyclicity up to 50 days postpartum. LH surge is important for ovulation and luteinisation of granulosa and theca cells into luteal cells and proliferation of blood vessels. Up to 79% of newly formed corpora lutea have central vacuola, filled with fluid. The study involved the total of 54 Holstein-Friesian cows, during first 40 days of lactation. Examinations of the ovaries, were performed in the period from 10 to 40 days postpartum. Ovaries and corpora lutea were first palpated and then examined using portable diagnostic ultrasound linear scanner MyLab®30 VETGold portable ultrasound linear scanner with endorectal linear probe LV 513, 5-7.5 MHz (both Esaote SpA, Italy). The same equipment was used to monitor BCS, while lamenes was assessed using Zinpro Locomotion Score for dairy cows. The highest number of corpora lutea was observed after 20 and 30 days postpartum in experimental and control groups. More corpora lutea were observed in multiparous cows. Higher numbers of corpora lutea with similar average size were observed in right ovaries of cows in both groups, while corpora lutea were bigger in multiparous cows. Numbers and sizes of corpora lutea, may give an insight in quality of restoration of ovarian cyclicity and a solid base for prediction on future reproductive performances.

Keywords

• corpora lutea
• puerperium
• ovulation
• dairy cows