Influence of commercial inactivated or modified-live virus vaccination at time of AI on corpus luteum development and function in beef cattle

Authors: EPPERSON, K - Northwest Missouri State University; RICH, J.J - Arkansas State University; MENEGATTI, ZOCA - University Of Tennessee; QUAIL, L - Texas Agrilife Research; ANDREWS, T - South Dakota State University; KLINE, A - Colby Community College; WHITE, F - Elanco Animal Health, Inc; DALY, R - South Dakota State University; Cushman, Robert - Bob; Snider, Alexandria - Alex; PERRY, G - Texas Agrilife Research

Submitted to: Animal Reproduction Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/28/2024
Publication Date: 8/29/2024
Citation: Epperson, K.M., Rich, J.J.J., Menegatti, Z.S., Quail, L.K., Andrews, T.N., Kline, A.C., White, F.J., Daly, R.F., Cushman, R.A., Snider, A.P., Perry, G.A. 2024. Influence of commercial inactivated or modified-live virus vaccination at time of AI on corpus luteum development and function in beef cattle. Animal Reproduction Science. 270. Article 107594. https://doi.org/10.1016/j.anireprosci.2024.107594.
DOI: https://doi.org/10.1016/j.anireprosci.2024.107594

Interpretive Summary: Care should be taken with timing of administration of pre-breeding vaccinations. Studies reported that vaccination too close to the breeding season can disrupt ovarian function leading to fewer pregnant cows. Our objective was to evaluate vaccination with an inactivated virus vaccine or modified-live virus vaccine on the ability of the corpus luteum to produce progesterone, the primary hormone supporting pregnancy in the cow. Administration of a commercial modified-live virus vaccine around the time of estrus increased programmed cell death and decreased the percentage of large luteal cells. This provides biological evidence of the negative impact of modified-live virus on normal estrous cycles and progesterone production. These effects should be taken into consideration by cow-calf producers when scheduling pre-breeding vaccinations to avoid luteal dysfunction that results in reduced pregnancy success.

Technical Abstract: Our objective was to evaluate the effect of vaccination with an inactivated virus vaccine (IVV) or modified-live virus (MLV) vaccine on the corpus luteum (CL). On d0, synchronized beef cows were treated with MLV (n = 70;BoviShield Gold FP5VL5), IVV (n = 16;ViraShield 6VL5HB), or were unvaccinated controls (n = 5). Plasma was collected from treated animals on d0 and every other day through d22. Plasma was analyzed for concentrations of progesterone and 15 cytokines. Between d10-13, selected females (n = 13) were ovariectomized; controls were slaughtered on d15/16 to obtain CL for histological evaluation. There were reduced numbers of large luteal cells (LLC) in MLV compared to IVV and controls (P < 0.0001), but IVV were similar to controls (P = 0.11). MLV had decreased LLC percentage compared to controls, and IVV were intermediate (P < 0.0001, MLV: 1.57 ± 0.33%, IVV: 2.99 ± 0.30%, Control: 6.45 ± 0.33%). Based on progesterone concentrations, 24% MLV and 0% IVV had an abnormal cycle following vaccination. Overall, MLV had reduced progesterone concentrations (P = 0.02; MLV: 3.61 ± 0.22; IVV: 4.81 ± 0.46ng/mL). The new CL that formed following an abnormal cycle in MLV had the greatest percentage (35.56 ± 5.5%) of apoptotic cells. Treatment by cycle status interaction, and time significantly affected IFN-', IP-10, MIP-1ß, and MCP-1 (P < 0.03), with several time points having elevated concentrations in abnormally cycling MLV animals. Collectively, this demonstrates MLV vaccination around estrus negatively influenced LLC, progesterone, and increased luteal apoptosis and pro-inflammatory cytokines.