Pregnancy rate in water buffalo following fixed-time artificial insemination using new or used intravaginal devices with two progesterone concentrations.

This study evaluated the pregnancy rate (PR) after timed artificial insemination (TAI) in water buffalo (<italic>Bubalus bubalis</italic>) during both non-breeding and breeding season, using either a new or reused intravaginal device (IVD) with two different progesterone concentrations. A total of 247 dairy buffalo cows were randomly assigned using a two-by-three factorial design and four replicates to the following groups: (1) new intravaginal device (IVD-New: DIB®, 1.0 g of P₄, <italic>n</italic> = 51 or CIDR®, 1.38 g of P₄, <italic>n</italic> = 55); (2) intravaginal device previously used once (9 days) (IVD-Used1x: DIB, <italic>n</italic> = 40 or CIDR, <italic>n</italic> = 51); or (3) intravaginal device previously used twice (18 days) (IVD-Used2x: DIB, <italic>n</italic> = 27 or CIDR, <italic>n</italic> = 23). On day 0, animals received the IVD plus 10.5 μg of buserelin acetate (GnRH) intramuscularly. On day 9, the devices were removed and 25 mg of PGF₂α plus 500 IU of eCG was given intramuscularly. On day 11 (48 h after IVD withdrawal), animals received 10.5 μg of GnRH and were artificially inseminated 8–12 h later. Data were analyzed using Proc Logistic of SAS®. Animals that received IVD-New-DIB, had a significantly higher PR (62.7%; <italic>P</italic> = 0.0193) compared to animals that received IVD-New-CIDR (40%). Pregnancy rate was not negatively affected by reusing both types of IVD. Overall PR (new and reused devices) was higher (<italic>P</italic> = 0.0055) in the DIB group (62.7%) compared to the CIDR group (45%). In conclusion, PR was higher in buffaloes treated with devices containing 1.0 g of P₄ (DIB®) compared to those receiving 1.38 g of P₄ (CIDR®). Reusing the intravaginal devices did not affect negatively PR/TAI, suggesting that P₄ concentrations within the TAI protocols in water buffaloes could be reduced, without impairing their fertility. [ABSTRACT FROM AUTHOR]