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ARS Home » Northeast Area » Beltsville, Maryland (BARC) » Beltsville Agricultural Research Center » Animal Genomics and Improvement Laboratory » Research » Publications at this Location » Publication #311836
Title: Dynamics of progesterone, TNF-a and a metabolite of PGF2a in blood plasma of beef cows following embryo transfer

Author
item MASON, M - Alcorn State University
item COPELAND, J - Alcorn State University
item CAUDRA, E - Alcorn State University
item Elsasser, Theodore
item JUNG, Y - Alcorn State University
item LARSON, J - Alcorn State University

Submitted to: Veterinary Medicine International
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/15/2014
Publication Date: 10/2/2014
Citation: Mason, M.C., Copeland, J., Caudra, E.J., Elsasser, T.H., Jung, Y., Larson, J. 2014. Dynamics of progesterone, TNF-a and a metabolite of PGF2a in blood plasma of beef cows following embryo transfer. Veterinary Medicine International. 1:1-7.

Interpretive Summary: Maintenance of pregnancy is dependent on blood concentrations of the hormone progesterone increasing significantly at the time of embryo implantation. Progesterone concentrations automatically rise after natural breeding with successful conception. Embryo transfer, a mainstay of the cattle industry employed to increase the efficiency of breeding, has a significant variable affecting the success rate, which is progesterone status at the time of implantation. The objective of this study was to assess the effectiveness of four treatments in increasing blood progesterone levels and its effects on two other hormones, TNF-a and PGF2a, that further influence embryo implantation and placental function. The treatments consisted of: no treatment (control), controlled internal drug releasing device (CIDR), human chorionic gonadotropin (hCG), or gonadotropin releasing hormone (GnRH) all of which modulate the hormone secretory profiles of the reproductive system. Following the initiation of treatments, embryos were transferred into recipient cows and the cows monitored to calculate the rate of retained embryos (% retained of the number transferred). Further, blood samples were collected at specified times to measure the effects of the treatments on TNF-a, progesterone and PGF2a. Embryo retention varied with the treatment with the highest rate of retention (62.5%) obtained with the hCG and lowest (13.3%) with GnRH. Hormone changes paralleled the retention rate with the highest progesterone concentrations attained with hCG. The data indicate that the success rate in embryo transfer can be increased by contemporary hormone treatments, especially hCG, that complement the intended process by increasing blood concentrations of the progesterone, main pregnancy-maintaining hormone.

Technical Abstract: Lactating beef cows received an embryo along with no treatment (control; n = 16), controlled internal drug releasing device (CIDR; n = 16), human chorionic gonadotropin (hCG; n = 15), or gonadotropin releasing hormone (GnRH; n = 15) to assess the effectiveness of these treatments in increasing blood progesterone (P4) and its effects on tumor necrosis factor-a (TNF-a) and prostaglandin F2a (PGF2a) after the transfer of embryos. All cows were previously synchronized for estrous by having a CIDR inserted for 7 d, followed by an injection of PGF2a one day after removal of the CIDR. Cows were observed for estrus (d 0) four times per day during the 80 h post-PGF2a; they received embryos on d 7 after exhibiting estrus. Blood samples were taken on d 7, d 14, and d 21 for analysis of P4 and TNF-a and on half the animals in each experimental group on d 14 (collected every 15 min for 2 h) and the remaining half on d 21 for PGF2a. Percent retention rates on d 60 were 56.2, 62.5, 46.7 and 13.3 for cows in the control, CIDR, hCG and GnRH groups, respectively. Progesterone was greater (P = 0.05) in cows receiving hCG compared to other groups on d 14. Mean concentrations of P4 in all treatment groups increased from d 7 to d 14 and declined (P = 0.05) from d 14 to d 21. Contrary to pregnant cows, non-pregnant cows had an overall decline in P4 and TNF-a from d 7 to d 21 (P = 0.05). Whereas, increased (P = 0.05) concentrations of PGF2a metabolite (PGFM) were seen in pregnant and non-pregnant animals on d 21; however, no difference (P = 0.05) was observed overall between the two groups.