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ARS Home » Plains Area » Miles City, Montana » Livestock and Range Research Laboratory » Research » Publications at this Location » Publication #384070
Research Project: Alleviating Rate Limiting Factors that Compromise Beef Production Efficiency

Location: Livestock and Range Research Laboratory

Title: Effect of pre and post-AI nutrition on ovarian dynamics, steroidogenesis, and expression of estrus in beef heifers

Author
item EPPERSON, KAITLIN - South Dakota State University
item RICH, JERICA J. - South Dakota State University
item Zezeski, Abby
item ZOCA, SAULO - South Dakota State University
item WALKER, JULIE - South Dakota State University
item Geary, Thomas
item PERRY, GEORGE - South Dakota State University

Submitted to: American Society of Animal Science Annual Meeting
Publication Type: Abstract Only
Publication Acceptance Date: 5/15/2021
Publication Date: 10/8/2021
Citation: Epperson, K.M., Rich, J.J., Zezeski, A.L., Zoca, S.M., Walker, J.A., Geary, T.W., Perry, G.A. 2021. Effect of pre and post-AI nutrition on ovarian dynamics, steroidogenesis, and expression of estrus in beef heifers. American Society of Animal Science Annual Meeting. 99(S3):131. https://doi.org/10.1093/jas/skab235.239.
DOI: https://doi.org/10.1093/jas/skab235.239

Interpretive Summary:

Technical Abstract: The objective of this study was to evaluate nutrition before and after artificial insemination (AI) on follicular dynamics, expression of estrus, and steroidogenesis. Seventy-nine beef heifers were randomly assigned to one of two dietary treatments (High;155% and Low;86% of maintenance energy) 30d prior to AI. Estrus was synchronized (PG 6-d CIDR protocol) and heifers received AI (d0) 8 to 12h following onset of estrus. On d0, heifers were randomly reassigned diets generating four Pre-x-Post-AI nutritional treatments; High-High (HH, n=20), High-Low (HL, n=20), Low-High (LH, n=19), and Low-Low (LL, n=20). Heifers remained on new diet treatments until embryo collection (flush; d7-8). Blood samples were collected daily from d-3 to d0, and on d1, 3, 5, 7 and 8 for plasma concentrations of estradiol (E2) and progesterone (P4). Dominant follicle diameter was evaluated on d-3 and d0, and CL diameter was recorded at flush. Statistical analyses were completed in SAS using the MIXED (body weight, E2, P4), GLIMMIX (expression of estrus), and GLM (ovarian parameters, interval to estrus) procedures. There were Pre-AI (P<0.0001) and Post-AI by time (P<0.0001) interactions on body weight; heifers in high and low treatments gained and lost weight, respectively, during both periods. Estradiol concentrations increased (P<0.0001) from d-3 (2.18±0.15pg/mL) to d0 (6.05±0.04pg/mL). Pre-AI diet increased proportion of heifers in estrus (80±6.3% vs. 59±7.9%; P=0.05), and dominant follicle size (11.7±1.42mm vs. 10.68±1.33mm; P=0.0016) in High vs. Low, respectively. Additionally, High Pre-AI heifers had greater P4 after AI compared to Low Pre-AI heifers (4.85±0.37ng/mL vs. 3.53±0.38ng/mL; P=0.015). Post-AI treatment did not influence concentrations of P4 (P=0.88). There was no effect of Pre, Post or Pre-x-Post-AI treatment on E2 concentrations, initial follicle size, follicle growth rate, interval to estrus, and CL size at flush (P>0.10). In conclusion, nutrient restriction before AI negatively impacted ovarian function, steroidogenesis, and expression of estrus.