Various intravaginal progesterone-releasing devices are commercially available and each is impregnated with different amounts of progesterone. An experiment was designed to characterize plasma progesterone release profiles from Cue-Mate in comparison with other commercially available progesterone-releasing devices. Cycling, lactating Holstein cows (n = 60; BCS between 2.0 and 3.0 out of 5) from commercial dairy farms in Argentina were used in 2 replicates. All cows received 2 injections of D+ cloprostenol (PGF, Bioprost-D�; Biotay, Buenos Aires, Argentina) 14 days apart and were randomly assigned to one of four groups to receive intravaginal devices as follows: Cue-Mate (1.56 g progesterone; Bioniche Animal Health, A/Asia Pty, Armidale, Australia; n = 10), DIB (1 g progesterone; Syntex SA, Argentina; n = 10), CIDR with 1.9 g progesterone (Pfizer Salud Animal S.A., Buenos Aires, Argentina; n = 10), or CIDR with 1.38 g progesterone (Pfizer Animal Health, Groton, CT, USA; n = 10). All devices were inserted 24 hours after the second PGF and were left in place for 31 days. Blood samples were taken for progesterone analysis at 6-hour intervals for the first 24 hours, then daily for a week, and every 2 days for an additional 25 days. Plasma progesterone concentrations were measured with a modified human double-antibody RIA kit (DPC Coat-A-Count�; Diagnostic Products Corporation, Los Angeles, CA, USA). Cows were observed twice daily to confirm that vaginal inserts were still in place. Time-series hormone data were analyzed using the MIXED procedure for repeated measures (SAS Institute, Inc., Cary, NC, USA). Main effects of device and time, the highest mean concentration of progesterone, and the mean day on which this occurred were compared by a protected LSD test. There was no evidence of cow discomfort with any of the vaginal devices, and loss rates did not differ. There was an effect of group (P < 0.001) and day (P < 0.001) for progesterone concentrations, but there was no interaction (P = 0.89). Peak concentrations of progesterone (ng mL-1) did not differ among groups (Cue-Mate: 5.0 � 1.1; DIB: 3.9 � 0.6; 1.9-g CIDR: 4.6 � 0.6; 1.38-g CIDR: 3.7 � 0.4; P = 0.51). Mean (� SEM) concentrations of progesterone over the 31-day insertion period differed between 1.9-g CIDR (1.8 � 0.2 ng mL-1) and DIB (1.5 � 0.1 ng mL-1, P < 0.006), with Cue-Mate (1.5 � 0.2 ng mL-1) and 1.38-g CIDR (1.6 � 0.1 ng mL-1) intermediate and not different from either. When data were evaluated from insertion until Day 7, mean plasma progesterone concentrations did not differ among groups (Cue-Mate: 2.2 � 0.2 ng mL-1; DIB: 2.2 � 0.1 ng mL-1; 1.9-g CIDR: 2.6 � 0.2 ng mL-1; 1.38-g CIDR: 2.1 � 0.1 ng mL-1). However, progesterone concentrations from insertion until Day 21 were higher (P < 0.03) in cows with a 1.9-g CIDR (2.1 � 0.1 ng mL-1) than in those with a DIB (1.6 � 0.1 ng mL-1) or a 1.38-g CIDR (1.6 � 0.1 ng mL-1), with Cue-Mate (1.7 � 0.1 ng mL-1) intermediate and not different. Based on progesterone release patterns, it was concluded that Cue-Mate intravaginal devices can be used in protocols for synchronization of estrus and ovulation as with other progesterone-releasing devices.
Three experiments were conducted to compare pregnancy rates in cows and heifers treated with intravaginal progesterone (P4)-releasing devices impregnated with either 0.5 or 1.0 g of P4 and inseminated at a fixed time (FTAI). In Experiment 1, 102 postpartum beef cows (Hereford and Angus crossbred with Tuli, 60 to 90 d postpartum) with a body condition score (BCS) of 2.5 to 3.0 (1 to 5 scale) were used. On Day 0, all cows received 2 mg of estradiol benzoate (EB; Syntex, Argentina) i.m. and were randomly assigned to receive an intravaginal progesterone-releasing device with 0.5 g of P4 (DIB 0.5 g; Syntex) or 1.0 g of P4 (DIB 1.0 g; Syntex). On Day 7, DIB devices were removed and all cows received 150 µg D(+)cloprostenol (Ciclase; Syntex) i.m. On Day 8, all cows received 1 mg EB and were FTAI 52 to 56 h after DIB removal. In Experiment 2, 93 Holstein cows that were 90 to 110 days in milk (DIM), producing on average 5000 kg of milk per lactation and with a BCS of 2.5 to 3.0 received the same treatments as those in Experiment 1. In Experiment 3, 100 Holstein heifers, 20 to 22 months old, with a BCS of 2.5 to 3.0, also received the same treatments as those in Experiment 1. Pregnancy rates in all experiments were determined by ultrasonography 35 days after FTAI and compared by chi-square test. No differences in pregnancy rates were detected between lactating beef cows, dairy cows, or dairy heifers treated with DIB devices impregnated with 0.5 or 1.0 g of P4 (Table 1). It was concluded that vaginal P4 releasing devices impregnated with 0.5 g or 1.0 g of P4 results in comparable pregnancy rates in FTAI protocols in beef and dairy cattle. Table 1. Pregnancy rates in postpartum beef cows, Holstein cows, and Holstein heifers treated with DIB devices impregnated with 0.5 or 1.0 g of P4 and subjected to FTAI
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.