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Image of Kyle McLean 


Dr. Kyle McLean Assistant Professor



ANSC - 320 Reproduction Physiology and Lactation     

ANSC 328 - Honors: Reproductive Physiology and Lactation  



2506 River Drive
248 Brehm Animal Science Building
Knoxville, Tennessee 37996
Phone: (865) 974-4203
Fax: (865) 974-7297
email: kmclea10@utk.edu











Postdoctoral Scholar; Animal Science; University of Kentucky; 2016 – 2018

Ph.D.; Animal Science; North Dakota State University; 2013 – 2016

M.S.; Animal Science; Oklahoma State University; 2011 – 2013

B.S.; Animal Science; Oklahoma State University; 2008 – 2010

A.S.; Animal Science; Eastern Wyoming College; 2006 – 2008 

Appointment: 85% Research | 15% Teaching 


Professional Interest: Reproductive Physiology: Placentation, and Uterine Environment

Selected images of Kyle's professional interestsEarly gestation and the establishment of pregnancy represent a critical period that may increase efficiency in beef production 1) by increasing the number of calves born via decreasing early embryonic loss and 2) by minimizing detrimental effects due to fetal programming, which may decrease offspring growth or reproductive efficiency. In beef cattle, fertilization rates are 90% or greater when a healthy spermatozoa comes into contact with a fertile oocyte (Bridges et al., 2013). Yet, only 55% of females remained pregnant by d 30 of gestation when subjected to artificial insemination (Bridges et al., 2013). Therefore, a better understanding of uterine receptivity, embryonic implantation, and placental development may increase the successfulness of the establishment of pregnancy.
The developing conceptus needs the placenta throughout pregnancy for nutrients, respiratory gases, and the ability to remove metabolic waste (Meschia et al., 1983; Bassil et al., 1995; Reynolds and Redmer, 1995). Therefore, placental development is closely related to fetal growth by facilitating transfer of nutrients, gases, and wastes (Patten, 1964; Ramsey, 1982) and is sensitive to maternal nutrient supply from the earliest stages of pregnancy (Reynolds and Redmer, 1995; 2001). Inadequate maternal nutrient supply leads to poor placental development, resulting in compromised fetal growth (Wu et al., 2006; Caton and Hess, 2010; Funston et al., 2010), embryonic loss (Reynolds et al., 2014), and detrimental long-term effects on the offspring (Reynolds and Caton, 2012). Embryonic development depends on healthy placental formation, but currently there are limited data showing how placental insufficiency occurs in cattle.

The syncytiotrophoblast is the placental layer in closest contact with maternal circulation and is responsible for a majority of the nutrient transport from maternal circulation to the fetus. In ruminants, trophoblast stem cells do not form an entire syncytiotrophoblastic layer but fuse to form syncytial plaques. These plaques are multinucleated cells that can contain up to 25 nuclei in sheep (Wooding, 1984) and 8 nuclei in cattle (Wooding and Wathes, 1980). Syncytium formation in the placenta is initiated by endogenous retroviral elements. In addition, Sharif et al. (2013) argued that endogenous retroviral elements function as nutrient sensors during the development of the placenta. Thus, expression may be influenced by maternal plane of nutrition during early gestation. The events of early gestation are critical to fetal and placental growth and lay the foundation for calf growth and overall beef production. This time period is the focus of my research and interest in ruminant reproduction.
My Research Program’s Areas of Interest:
  • The uterine environment’s role in pregnancy establishment and efficiency of placentation
  • The influence of maternal and paternal nutrient plane and nutrient supply on fetal and placental development (i.e. “fetal programming”)
  • Elucidation of the functions of endogenous retroviral elements during gestation
  • The role of immunological responses on the uterine environment, placentation, and the establishment of pregnancy 

Selected Publications

  • McLean, K. J., M. S. Crouse, M. R. Crosswhite, N. Negrin Pereira, C. R. Dahlen, P. P. Borowicz, L. R. Reynolds, A. K. Ward, B. W. Neville, and J. S. Caton. 2018. The effects of nutrient restriction on mRNA expression on endogenous retroviruses, interferon-tau, and pregnancy specific protein-B during the establishment of pregnancy in beef heifers. J. Anim. Sci.:(epub ahead of print). doi: 10.1093/jas/skx001 

  • McLean, K. J., M. S. Crouse, M. R. Crosswhite, D. N. Black, C. R. Dahlen, P. P. Borowicz, L. R. Reynolds, A. K. Ward, B. W. Neville, and J. S. Caton. 2017. Endogenous retroviral gene elements (syncytin-Rum1 and BERV-K1), interferon-τ, and pregnancy associated glycoprotein-1 are differentially expressed in maternal and fetal tissues during the first 50 days of gestation in beef heifers. Transl. Anim. Sci. 1:239-249. doi:10.2527/tas2017.0026. 

  • McLean, K. J., M. S. Crouse, M. R. Crosswhite, N. Negrin Pereira, C. R. Dahlen, P. P. Borowicz, L. R. Reynolds, A. K. Ward, B. W. Neville, and J. S. Caton. 2017. Impacts of maternal nutrition on placental vascularity and mRNA expression of angiogenic factors during the establishment of pregnancy in beef heifers. Transl. Anim. Sci. 1:160-167. doi:10.2527/tas2017.0019. 

  • McLean, K. J., C. R. Dahlen, P. P. Borowicz, L. R. Reynolds, B. W. Neville, and J. S. Caton. 2016. Technical Note: Development of a technique to ovario-hysterectomize cattle for use in gestational research. J. Anim. Sci. 94:5089-5096. doi:10.2527/jas.2016-0761. 

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