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An electronically controlled intravaginal hormone delivery device successfully induced luteal regression in dairy cattle.

M. Masello




An electronically controlled intravaginal hormone delivery device successfully induced luteal regression in dairy cattle.
M. Masello*1, Y. Ren2, D. Erickson2, J. O. Giordano1. 1Department of Animal Science, Cornell University Ithaca, NY, 2Sibley School of Mechanical and Aerospace Engineering, Cornell University Ithaca, NY.

Our objective was to develop and validate an electronically-controlled hormone delivery device for reproductive control of cattle. After development and in vitro testing of a prototype device for intravaginal (IVG) hormone release, we aimed to demonstrate the feasibility of inducing luteal regression by automated treatment with PGF2a (PGF). The IVG device comprises an outer 3D-printed plastic housing, fluid reservoirs connected to delivery pumps and tubing, a programmable circuit board, and a retention mechanism. For in vitro testing, 4 pumps were programmed to release different target volumes (0.1, 0.2, 0.5, 1.0, and 2.0 g) in 4 replicates (n = 80). A Bland-Altman plot was constructed to assess the magnitude of disagreement between expected and delivered volumes. Observations fell within acceptable limits of agreement (1.96 SD) > 95% of the time, indicating overall good agreement (mean difference = 0.008 g). To assess in vivo performance of the IVG device, lactating Holstein cows with at least 1 corpus luteum = 15 mm in diameter were randomly allocated to 1 of 3 treatments: IM-PGF (n = 6); 2 25 mg intramuscular doses of PGF (Dinoprost) 24 h apart, DEV-PGF (n = 6); 4 25 mg doses of PGF released automatically by the IVG device every 12 h, and DEV-CTL (n = 4); insertion of an empty IVG device (placebo control). Blood samples were collected at 0, 12, 24, 36, 48, and 72 h after treatment. Data were analyzed by ANOVA with repeated measures in SAS. All devices (10/10) remained in situ until removed at 48 h. Progesterone (P4) concentrations from 0 to 72 h were affected by treatment (P < 0.01), time (P < 0.01), and their interaction (P < 0.01). Concentrations of P4 did not differ at time 0 but differed from 24 to 72 h as cows in IM-PGF and DEV-PGF had lesser P4 than cows in DEV-CTL. Conversely, P4 did not differ for IM-PGF and DEV-PGF during the experiment. We conclude that the current IVG hormone releasing device prototype can be programmed to automatically release PGF for successful induction of luteal regression in lactating dairy cows.

Keywords: automation, hormone delivery, dairy cow.

Biography: Magdalena Masello obtained her DVM degree in 2014 from the University of the Republic in Uruguay. In 2016 she started her PhD program at Cornell University's Department of Animal Science working in Dr. Julio Giordano's laboratory. Her research is focused in dairy cattle reproductive physiology and management.