Effect of intrauterine administration of platelet-rich plasma two days before timed artificial insemination in dairy cows on endometrial thickness and conception rate

This study investigated the effects of intrauterine platelet-rich plasma (PRP) administered during the follicular phase on endometrial thickness and conception rate (CR) in dairy cows. Cows were randomly assigned to a PRP group (n=36) or a control group (n=36). All cows underwent timed artificial insemination (TAI). Endometrial thickness and sex-steroid hormone concentrations were measured before and after TAI. PRP was prepared by double-spin centrifugation without activation. The platelet count in PRP was 100.7 ± 32.7 × 10⁴/μL (47.1 to 187.3 × 10⁴/μL), corresponding to a 4.0 ± 0.7-fold concentration (3.0-5.3-fold). Two days before TAI, 10 mL PRP was administered intrauterinely to cows in the PRP group. Endometrial thickness at TAI was significantly greater in the PRP group than in controls (25.36 ± 7.07 mm compared with 20.45 ± 4.18 mm; P<0.05). CR after TAI did not differ between groups (58.3% for the PRP group and 47.2% for the control group). Estradiol-17β and progesterone levels were similar in both groups. Because hormone sampling was intermittent, sex-steroid dynamics were captured only fragmentarily, and independence from steroid effects cannot be concluded. Together, these findings indicate a positive local effect of PRP on the endometrium, as evidenced by increased endometrial thickness. To our knowledge, this is the first study to evaluate intrauterine PRP administered two days before TAI and its effect on endometrial thickness in dairy cows.