Research Summary - 2
Early identification of non-pregnant lactating dairy cows based on cervical concentrations of interferon-tau
| Date/Time: |
8/28/2026
15:30
|
| Author: |
Rafael S Bisinotto |
| Clinic: |
University of Florida |
| City, State, ZIP: |
Gainesville, FL 32610 |
R.S. Bisinotto, DVM, PhD
1
;
V.A.B. Primo, DVM, MPVM
1
;
M.B. Ugarte Marin, MS
1
;
D.K. Roese, DVM
1
;
J.V. Bishop, MS
2
;
A. Guzeloglu, DVM, PhD
2
;
T.R. Hansen, PhD
2
;
1Department of Large Animal Clinical Sciences, College of Veterinary Medicine, University of Florida, Gainesville, FL 32610
2Department of Biomedical Sciences, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, CO 80523
Introduction:
Early identification of non-pregnant cows allows for a reduction of reinsemination interval, thus increasing service rate improving reproductive efficiency in dairy herds. Interferon-tau (IFNT) secreted by trophectoderm cells of the elongating conceptus as part of maternal recognition of pregnancy has been detected in the cervical lumen of pregnant cows, which can be used as a marker for the presence of a viable embryo before it can be detected by transrectal ultrasonography. The objectives of this study were to 1) evaluate the use of IFNT concentration in cervical swabs for identification of non-pregnant cows from day 15 to 18 after artificial insemination (AI) and 2) characterize ovarian structures on day 17 in non-pregnant cows.
Materials and methods:
Concentration of IFNT was measured in cervical swabs collected daily from day 15 to 18 after AI (day 0) in lactating Holstein cows (n = 46). A custom bovine swab protected by a plastic pipette and a sanitary sheath was inserted through the vagina and guided to the cervix by rectal palpation. The pipette was exposed to the cervical lumen where the swab was exposed for 10 seconds. Swabs were placed in 300 µL of PBS and kept on ice until arrival at the laboratory. Samples were assayed for IFNT concentration using a sandwich ELISA validated for bovine samples. Cows with IFNT concentration above the limit of detection were considered to have a viable embryo. Cows had their ovaries scanned on day 17 after AI using a portable ultrasound machine equipped with a 4.5-8.5 MHz linear probe and classified according to the presence of putative functional corpus luteum (CL ≥ 20 mm) and follicles with ovulatory capacity (≥ 10 mm). Pregnancy was determined by transrectal ultrasonography on day 32 based on the presence of an amniotic vesicle containing an embryo with heartbeat. Sensitivity (Se), specificity (Sp), false negative rate (FNR), and respective 95% confidence intervals (CI) were calculated.
Results:
Overall, 69.6% of cows were diagnosed as pregnant by ultrasonography on day 32. Prediction of pregnancy status on day 32 after AI based on IFNT measurements was numerically less accurate on day 15 (Se = 0.78, 0.64-0.92; Sp = 0.57, 0.31-0.83; FNR = 0.22, 0.08-0.36) compared with days 16 (Se = 0.94, 0.85-1.00; Sp = 0.86, 0.67-1.00; FNR = 0.06, 0.00-0.15), 17 (Se = 0.97, 0.91-1.00; Sp = 0.71, 0.48-0.95; FNR = 0.03, 0.00-0.09), and 18 after AI (Se = 0.94, 0.85-1.00; Sp = 0.64, 0.39-0.89; FNR = 0.07, 0.00-0.15). All cows diagnosed as non-pregnant had at least one follicle ≥ 10 mm on day 17. The proportion of cows diagnosed as non-pregnant on days 15, 16, 17, and 18 that had at least one CL ≥ 20 mm on day 17 were 93.3, 85.7, 81.8, and 81.8%, respectively.
Significance:
Accuracy of a test based on detection of IFNT in cervical swabs to identify non-pregnant cows from day 16 to 18 after AI coupled with the large proportion of cows with putative functional CL and follicles with ovulatory capacity on day 17 support further investigation regarding its application for early resynchronization programs. Moreover, the economic impact of iatrogenic abortions in cows misidentified as non-pregnant based on the absence of INFT signal must be contrasted against the benefit of decreasing time to reinsemination and reducing days open.
