Corpus luteum blood flow correlation with circulating progesterone during the bovine estrous cycle

Abstract Text:

Corpus luteum blood flow correlation with circulating progesterone during the bovine estrous cycle.

A. Egloff¹, E. Taylor¹, B. Funnell², K.R. Stewart¹

¹ Purdue University, Department of Animal Science

915 W. State Street

West Lafayette, IN 47907-2054, USA

² Purdue University, Department of Veterinary Clinical Sciences

625 Harrison Street

West Lafayette, IN 47907-2504, USA

The purpose of this study was to evaluate a subjective scoring system to evaluate corpus luteum (CL) function during the beef cattle estrous cycle as a means to evaluate CL function in recipient cows.  Sixteen open Simmental/Angus cows ranging from ages of 2 years to 6 years (mean age = 3) were randomly selected from the Purdue Animal Research Education Center. Cows ranged in BCS from 4.33 to 7 (mean = 5.10) and ranged in body weight from 1025-1645 (mean = 1318.44). Blood samples were collected every day for 28 consecutive days via venous jugular puncture.  The blood samples were collected in vacutainer tubes containing EDTA. It was then spun using a centrifuge and froze. Plasma progesterone concentrations were determined via Immulite 1000 progesterone kits by Siemens. The kits test on a solid phase, competitive immunoassay utilizing the enzyme labeled chemiluminescent technology. Transrectal ultrasonography was performed every other day to visualize the ovarian structures (Sonosite Micromaxx). If a CL was present, a Color-flow Doppler sonography subjective score was recorded on a scale from 0-3 based on the following criteria: 0) no Doppler color; 1) small Doppler color on periphery of CL; 2) up to 80% of CL having Doppler color; and 3) greater than 80% of CL having Doppler color. Results from compiled testing were then evaluated using Spearman Correlation Coefficients in SAS® (v9.3, SAS Inst., Cary, NC). Plasma progesterone concentration was correlated with Doppler score (r=0.45, p<0.0001) where increasing Doppler score correlated with higher plasma progesterone concentrations.  For each cow, a peak progesterone concentration and an average progesterone concentration for the last 4 days where progesterone was elevated in the blood were calculated.  Peak and average progesterone concentrations were correlated with age (r= -0.555, p=0.032) where younger animals had higher progesterone concentrations.  Peak and average progesterone concentrations were not correlated with body weight or body condition score (p=0.6705 and P=0.4949, respectively).  Overall, the subjective Doppler scoring system used in this study is correlated with plasma progesterone concentrations and could be used in recipient cows to evaluate functionality of the CLs prior to embryo transfer.

Keywords: Plasma Progesterone, Corpus Luteum