Corpus luteum dynamics after ovulation induction with or without previous exposure to progesterone in prepubertal Nellore heifers

Author(s):Show less -

Vrisman, Dayane Priscila ^[1] ; Bastos, Natalia Marins ^[1] ; Rossi, Guilherme Fazan ^[1] ; Rodrigues, Naiara Nantes ^[1] ; Bueno Borges, Luisa Pucci ^[2] ; Taira, Augusto Ryonosuke ^[1] ; Paro de Paz, Claudia Cristina ^[3] ; Nogueira, Guilherme de Paula ^[4] ; Maia Teixeira, Pedro Paulo ^[2] ; Monteiro, Fabio Morato ^[3] ; Franco Oliveira, Maria Emilia ^[1]

Affiliation

^[1] Univ Estadual Paulista Julio de Mesquita Filho FC, Dept Med Vet Prevent & Reprod Anim, Via Acesso Prof Paulo Donato Castellane, S-N, BR-14884900 Sao Paulo - Brazil

^[2] Univ Fed Para, Inst Med Vet, BR-66075110 Belem, Para - Brazil

^[3] Ctr APTA Bovinos Corte, Inst Zootecnia, BR-14160970 Sao Paulo - Brazil

^[4] Fac Med Vet Aracatuba FMVA UNESP, Lab Endocrinol Anim, BR-16050680 Sao Paulo - Brazil

• Document type: Journal article
• Source: Theriogenology; v. 106, p. 60-68, JAN 15 2018.
• Web of Science Citations: 2

Abstract

The objectives of this study were 1) to monitor corpus luteum (CL) dynamics after two different protocols of ovulation induction in prepubertal Nellore heifers, and 2) to determine differences in luteal function. Fifty-seven heifers (weight 289.61 +/- 32.28 kg, BCS 5.66 +/- 0.65, age 17.47 +/- 0.81 months) were divided into two groups: GP4+GnRH received a progesterone (P4) device of 3rd use for 10 days, followed by the administration of 0.02 mg buserelin acetate (GnRH) 48 h after removal of the device, and GGnRH received only GnRH. The CLs formed were monitored by ultrasonography every 2 days until their functional regression (decrease in the color Doppler signal and serum P4 concentration < 1 ng/mL), determining their diameter and area, numerical pixel value (NPV), pixel heterogeneity, and vascularization percentage. The peak systolic velocity, end diastolic velocity, resistivity index and pulsatility index (PI) of the ovarian artery and serum P4 concentration were also measured. A lifespan of the CL of more than 16 days was classified as normal-function and of less than 16 days as premature regression. The variables were compared between treatments, CL categories (normal-functional, prematurely regressed or non-functional), days of evaluation, and their interactions using the MIXED procedure of the SAS program (p <= 0.05). Three animals of each group (6/57 = 11%) did not respond to treatment, corresponding to an ovulation rate of 89%. There was a higher percentage of normal-function CLs in GP4+GnRH (81%) and a higher percentage of non-functional CLs in GGnRH (52%; P4 concentration < 1 ng/mL in all assessments). Normal-function CLs exhibited a greater area, vascularization percentage and P4 concentration than prematurely regressed and non-functional CLs. Lower diameter, area, NPV and P4 concentration were observed for non-functional CLs, but there was no difference in vascularization percentage compared to prematurely regressed CLs. Progesterone concentration was efficient in diagnosing CL function and was positively correlated with CL area (r = 0.62; p < 0.001) and vascularization percentage (r = 038; p < 0.001). Diameter and PI were important for the early diagnosis of non-functional and prematurely regressed CLs, respectively. In conclusion, luteal function differed for the first CL that develops after ovulation induction in prepubertal heifers. Ultra-sonographic parameters (diameter, area, NPV, vascularization percentage, and PI) can be used to predict CL function. (C) 2017 Elsevier Inc. All rights reserved. (AU)

• FAPESP's process: 15/13079-0 - Evaluation of attributes sonographic (mode-B and doppler) of corpus luteum after puberty induction in Nellore heifers and its relation with functionality
• Grantee: Dayane Priscila Vrisman
• Support Opportunities: Scholarships in Brazil - Master