Skip to main content
ARS Home » Plains Area » Miles City, Montana » Livestock and Range Research Laboratory » Research » Publications at this Location » Publication #329082
Title: Identification of beef heifers with superior uterine capacity for pregnancy

Author
item Geary, Thomas
item BURNS, GREGORY - University Of Missouri
item MORAES, JOAO - University Of Missouri
item MOSS, JAMES - University Of Florida
item DENICOL, ANNA - University Of Florida
item DOBBS, KYLE - University Of Florida
item ORTEGA, M - University Of Florida
item HANSEN, PETER - University Of Florida
item WEHRMAN, MICHAEL - Rocky Mountain Laboratory
item NEIBERGS, HOLLY - Washington State University
item O'NEIL, ELEANORE - University Of Missouri
item BEHURA, SUSANTA - University Of Missouri
item SPENCER, THOMAS - University Of Missouri

Submitted to: Biology of Reproduction
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/6/2016
Publication Date: 7/14/2016
Citation: Geary, T.W., Burns, G.W., Moraes, J., Moss, J.I., Denicol, A.C., Dobbs, K.B., Ortega, M.S., Hansen, P.J., Wehrman, M.E., Neibergs, H., O'Neil, E., Behura, S., Spencer, T.E. 2016. Identification of beef heifers with superior uterine capacity for pregnancy. Biology of Reproduction. 95(2):47, 1-12.

Interpretive Summary: Poor fertility is a major problem in animals and humans. Many pregnancies are lost during early stages. Exact problems with early pregnancy are not well understood. In our first study, 270 yearling cows were used. Embryo transfer (ET) was used to identify more and less fertile cows. Cows received ET four times. Cows classified as high fertile (HF) were pregnant each time following ET. Cows classified as subfertile (SF) were pregnant about half of the time. Cows classified as infertile (IF) were never pregnant. In study two, progesterone was measured in blood of cows for 20 days after ET. Progesterone was not different in cows from different fertility groups. In study three, an embryo was transferred into cows on day 7 and recovered 7 days later. Embryo recovery rate and embryo size were not different among the fertility groups. A biopsy was collected from each cow at the time of embryo recovery. Biopsies were analyzed for differential gene expression between fertility groups. There were a number of differentially expressed genes (DEG) between the different fertility groups. We conclude that communication between the embryo and uterus leading to embryo implantation failure is a main cause of pregnancy failure in cattle.

Technical Abstract: Infertility and subfertility represent major problems in domestic animals and humans, and the majority of embryonic loss occurs during the first month of gestation that involves pregnancy recognition and conceptus implantation. The critical genes and physiological pathways in the endometrium that mediate pregnancy establishment and success are not well understood. In Study One, 270 predominantly Angus heifers were classified based on fertility using four rounds of serial embryo transfer (ET) to select animals with intrinsic differences in pregnancy loss. In each round, a single in vitro-produced high-quality embryo was transferred into heifers on day 7 post-estrus and pregnancy was determined on days 28 and 42 by ultrasound and then terminated. Heifers were classified based on pregnancy success as high fertile (HF), subfertile (SF), or infertile (IF). In Study Two, fertility-classified heifers were resynchronized and bred with semen from a single high fertility bull. Blood samples were collected every other day from days 0 to 36 post-mating. Pregnancy rate was determined on day 28 by ultrasound and tended to be higher in HF (70.4%) and SF (46.7%) than IF (0%) heifers. Progesterone concentrations in serum during the first 20 days post-estrus were not different in non-pregnant heifers and also not different in pregnant heifers among fertility groups. In Study Three, a single in vivo-produced embryo was transferred into fertility-classified heifers on day 7 post-estrus. The uteri were flushed on day 14 to recover embryos, and endometrial biopsies were obtained from the ipsilateral uterine horn. Embryo recovery rate and conceptus length and area were not different among the heifer groups. RNA was sequenced from the day 14 endometrial biopsies of pregnant HF, SF and IF heifers (n=5 per group) and analyzed by edgeR robust analysis. There were 26 differentially expressed genes (DEG) in the HF compared to SF endometrium, 12 DEG for SF compared to IF endometrium, and 3 DEG between the HF and IF endometrium. Many of the DEG encoded proteins involved in immune responses and are expressed in B cells. Results indicate that pre-implantation conceptus survival and growth to day 14 is not compromised in SF and IF heifers. Thus, the observed difference in capacity for pregnancy success in these fertility-classified heifers is manifest between days 14 and 28 when pregnancy recognition signaling and conceptus implantation must occur for the establishment of pregnancy.