Circulating progesterone concentrations in nonlactating Holstein cows during reuse of intravaginal progesterone implants sanitized by autoclave or chemical disinfection

Abstract

The aim of this study was to compare plasma progesterone (P4) concentrations in nonlactating, multiparous Holstein cows (n = 24) treated with 2 types of intravaginal implants containing either 1.0 or 1.9 g of P4 either at the first use or during reuse of the implants after sanitizing the implant by autoclave or chemical disinfection. In a completely randomized design with a 2 × 3 factorial arrangement and 2 replicates, every cow underwent 2 of 6 treatments. Two sources of P4 [controlled internal drug release (1.9 g of P4) from Zoetis (São Paulo, Brazil), and Sincrogest (1.0 g of P4) from Ourofino (Cravinhos, Brazil)] and 3 types of processing, new (N), reused after autoclave (RA), and reused after chemical disinfection (RC), were used. After inducing luteolysis to avoid endogenous circulating P4, the cows were randomized in 1 of 6 treatments (1.9 g of N, 1.9 g of RA, 1.9 g of RC, 1.0 g of N, 1.0 g of RA, and 1.0 g RC). Cows were treated with the implants for 8 d and during this period blood samples were collected at 0, 2, 12, 24, 48, 72, 96, 120, 144, 168, and 192 h. Statistical analyses were performed using Proc-Mixed and the mean ± standard error of the mean P4 concentrations were calculated using the Proc-Means procedures of SAS 9.4 (SAS Institute Inc., Cary, NC). No interaction between treatments was observed. Comparing types of implant, average P4 concentrations during treatments were greater for 1.9 g than 1.0 g (1.46 vs. 1.14 ± 0.04 ng/mL). When types of processing were compared, average P4 concentrations did not differ between autoclaved and new inserts (1.46 vs. 1.37 ± 0.05 ng/mL; respectively), but both were greater than chemically disinfected implants (1.09 ± 0.04 ng/mL). Within 1.9-g P4 inserts, P4 concentrations from autoclaved implants were greater than new, which were greater than chemically disinfected (1.67 ± 0.06 vs. 1.49 ± 0.07 vs. 1.21 ± 0.05 ng/mL; respectively). For 1.0-g P4 implants, P4 concentrations from autoclaved did not differ from new, but both were greater than chemically disinfected (1.20 ± 0.08 vs. 1.24 ± 0.06 vs. 0.97 ± 0.05 ng/mL; respectively). In conclusion, the mean plasma P4 concentration in nonlactating Holstein cows was greater for 1.9 than 1.0 g of P4 and regardless of the type of implant, the autoclaving process provided greater circulating P4 in relation to chemical disinfection, and similar or greater P4 concentrations compared with a new implant.

Follicular dynamics, circulating progesterone, and fertility in Holstein cows synchronized with reused intravaginal progesterone implants that were sanitized by autoclave or chemical disinfection

“…In our study, P4 concentrations were not affected by treatments on d −10 (before any treatment) or −3 (Table 1). Based on P4 profiles of 1.9-g intravaginal implants from a previous study (Melo et al, 2018) it was expected that cows that received an autoclaved P4 implant would have greater circulating P4 throughout the protocol, particularly during the first 4 d. Unexpectedly, P4 concentrations were slightly but significantly (P = 0.05) greater on d −2 in cows with chemically disinfected rather than autoclaved P4 implants. Possibly, this unexpected difference could be due to a less effective induction of luteolysis in cows receiving chemically disinfected P4 implants.…”

“…This experiment was performed with reused 1.9-g intravaginal P4 implants (previously used for 8 d in lactating dairy cows) that were either autoclaved or chemically disinfected before reuse, based on the differences in circulating P4 profiles that were obtained from a previous study from our laboratory (Melo et al, 2018). Cerri et al (2009) compared a new and reused-after-autoclaving 1.38-g P4 implant in a GnRHbased protocol, but no previous comparison has been made between P4 implants prepared by the 2 different disinfection/sanitization techniques that produced such dramatic differences in circulating P4 profiles.…”

“…Nevertheless, the lack of treatment difference in P/AI for cows with or without a CL may indicate that the increased P4 from the autoclaved implant may be insufficient to produce physiologically significant changes in circulating P4 in cows either with or without a CL. Use of a single new CIDR or autoclaved, reused CIDR did not produce luteal phase concentrations of circulating P4 in high-producing lactating dairy cows without a CL, as they were initially developed for nonparous dairy heifers (300-400 kg of BW) in New Zealand (Macmillan et al, 1991;Melo et al, 2018). High-producing dairy cows without a CL require 2 of these implants to achieve sufficient circulating P4 to optimize fertility (Padula and Macmillan, 2006;Bisinotto et al, 2013;Pereira et al, 2017. Although no differences were observed in the proportion of cows ovulating at the beginning of the protocol, the earlier wave emergence observed in the AUT group from cows not bearing a CL may be explained by ~18% more cows ovulating in this group on d −10 (Table 1).…”

“…For the purposes of our physiological studies, we chose to compare the autoclaved versus chemically disinfected, reused 1.9-g P4 implants because of the dramatic differences in the P4 profile throughout the 8-d treatment period, as shown in our previous study (Melo et al, 2018). In this previous study, the average circulating P4 was greater (P < 0.05) for the autoclaved, reused controlled internal drug release (CIDR; 1.67 + 0.06 ng/mL) than the new CIDR (1.49 + 0.07), and both were greater than the chemically disinfected CIDR (1.21 + 0.05).…”

Downregulated luteolytic pathways in the transcriptome of early pregnancy bovine corpus luteum are mimicked by interferon-tau in vitro

“…Pregnancy was confirmed by identifying an elongated embryo in uterine flushes, ISGs expression and serum P4 concentration 7 cows were chosen. The presence of a functional CL was confirmed by measuring plasma progesterone using a commercial RIA kit (CT Progesterone, MP Biomedicals LLC, Solon, OH, USA), following the manufacturer’s instructions as previously described and validated for bovine plasma [ 73 ]. The intra- and inter-assay CVs were 2.1 and 2.2% respectively, and the sensitivity was 0.05 ng/mL.…”