Follicular Fluid from Cows That Express Estrus During a Fixed-Time Artificial Insemination Protocol Promotes Blastocyst Development

It is not yet understood why cows that exhibit estrus and ovulate are more likely to become pregnant than those that ovulate but do not exhibit estrus during a fixed-time artificial insemination (FTAI) protocol. The objective of this work was to determine whether the follicular fluid from cows that...

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Main Authors: Audra W. Harl, Verónica M. Negrón-Pérez, Jacob W. Stewart, George A. Perry, Alan D. Ealy, Michelle L. Rhoads
Format: Article
Language:English
Published: MDPI AG 2025-04-01
Series:Journal of Developmental Biology
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Online Access:https://www.mdpi.com/2221-3759/13/2/14
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author Audra W. Harl
Verónica M. Negrón-Pérez
Jacob W. Stewart
George A. Perry
Alan D. Ealy
Michelle L. Rhoads
author_facet Audra W. Harl
Verónica M. Negrón-Pérez
Jacob W. Stewart
George A. Perry
Alan D. Ealy
Michelle L. Rhoads
author_sort Audra W. Harl
collection DOAJ
description It is not yet understood why cows that exhibit estrus and ovulate are more likely to become pregnant than those that ovulate but do not exhibit estrus during a fixed-time artificial insemination (FTAI) protocol. The objective of this work was to determine whether the follicular fluid from cows that exhibit estrus contributes to the increased likelihood of pregnancy. Lactating crossbred cows were subjected to an FTAI estrous synchronization protocol. Estrous behavior was observed and recorded prior to transvaginal follicle aspiration from cows that did (estrus, <i>n</i> = 7) or did not exhibit estrus (non-estrus, <i>n</i> = 6). Follicular fluid (25%) was then added to in vitro maturation media for the maturation of oocytes (<i>n</i> = 1489) from slaughterhouse ovaries. Cleavage rates were not affected by the estrous status of the cows from which the follicular fluid was collected. Blastocyst rates, however, were greater following maturation in the presence of follicular fluid from estrus cows compared to non-estrus cows (<i>p</i> ≤ 0.01). This difference in blastocyst rates was not related to blastocyst cell numbers (inner cell mass, trophoblast, and total), as they did not differ between estrus and non-estrus animals. This study demonstrates that the follicular fluid, and thus, the follicular environment just prior to ovulation does indeed contribute to improved pregnancy rates following FTAI.
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spelling doaj-art-eff3a7ded0dc44a9871175a183ae22992025-08-20T03:27:17ZengMDPI AGJournal of Developmental Biology2221-37592025-04-011321410.3390/jdb13020014Follicular Fluid from Cows That Express Estrus During a Fixed-Time Artificial Insemination Protocol Promotes Blastocyst DevelopmentAudra W. Harl0Verónica M. Negrón-Pérez1Jacob W. Stewart2George A. Perry3Alan D. Ealy4Michelle L. Rhoads5School of Animal Sciences, Virginia Tech, Blacksburg, VA 24061, USASchool of Animal Sciences, Virginia Tech, Blacksburg, VA 24061, USASchool of Animal Sciences, Virginia Tech, Blacksburg, VA 24061, USATexas A&M AgriLife Research and Extension Center, Overton, TX 75684, USASchool of Animal Sciences, Virginia Tech, Blacksburg, VA 24061, USASchool of Animal Sciences, Virginia Tech, Blacksburg, VA 24061, USAIt is not yet understood why cows that exhibit estrus and ovulate are more likely to become pregnant than those that ovulate but do not exhibit estrus during a fixed-time artificial insemination (FTAI) protocol. The objective of this work was to determine whether the follicular fluid from cows that exhibit estrus contributes to the increased likelihood of pregnancy. Lactating crossbred cows were subjected to an FTAI estrous synchronization protocol. Estrous behavior was observed and recorded prior to transvaginal follicle aspiration from cows that did (estrus, <i>n</i> = 7) or did not exhibit estrus (non-estrus, <i>n</i> = 6). Follicular fluid (25%) was then added to in vitro maturation media for the maturation of oocytes (<i>n</i> = 1489) from slaughterhouse ovaries. Cleavage rates were not affected by the estrous status of the cows from which the follicular fluid was collected. Blastocyst rates, however, were greater following maturation in the presence of follicular fluid from estrus cows compared to non-estrus cows (<i>p</i> ≤ 0.01). This difference in blastocyst rates was not related to blastocyst cell numbers (inner cell mass, trophoblast, and total), as they did not differ between estrus and non-estrus animals. This study demonstrates that the follicular fluid, and thus, the follicular environment just prior to ovulation does indeed contribute to improved pregnancy rates following FTAI.https://www.mdpi.com/2221-3759/13/2/14cattleembryofollicular fluidestrusfertilitypregnancy
spellingShingle Audra W. Harl
Verónica M. Negrón-Pérez
Jacob W. Stewart
George A. Perry
Alan D. Ealy
Michelle L. Rhoads
Follicular Fluid from Cows That Express Estrus During a Fixed-Time Artificial Insemination Protocol Promotes Blastocyst Development
Journal of Developmental Biology
cattle
embryo
follicular fluid
estrus
fertility
pregnancy
title Follicular Fluid from Cows That Express Estrus During a Fixed-Time Artificial Insemination Protocol Promotes Blastocyst Development
title_full Follicular Fluid from Cows That Express Estrus During a Fixed-Time Artificial Insemination Protocol Promotes Blastocyst Development
title_fullStr Follicular Fluid from Cows That Express Estrus During a Fixed-Time Artificial Insemination Protocol Promotes Blastocyst Development
title_full_unstemmed Follicular Fluid from Cows That Express Estrus During a Fixed-Time Artificial Insemination Protocol Promotes Blastocyst Development
title_short Follicular Fluid from Cows That Express Estrus During a Fixed-Time Artificial Insemination Protocol Promotes Blastocyst Development
title_sort follicular fluid from cows that express estrus during a fixed time artificial insemination protocol promotes blastocyst development
topic cattle
embryo
follicular fluid
estrus
fertility
pregnancy
url https://www.mdpi.com/2221-3759/13/2/14
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