Education
Doctor of Philosophy, Purdue University: 1992
Master of Science, The Ohio State University: 1987
Bachelor of Science, The Ohio State University: 1982

Research
Our research is focused on neuroendocrine control of reproduction in the pig.  Specific issues currently being studied involve the control of GnRH and gonadotropin secretion by the insulin-like growth factor (IGF) system.  Currently, we are using models to examine the effects of feed restriction and steroids and how they may effect serum and tissue concentrations of IGF-I, IGF-binding proteins and IGF receptors in the brain and pituitary gland.

Outreach
Develop and implement an artificial insemination (AI) program in swine.  The objective is to teach individuals the techniques necessary to successfully use AI to increase reproductive efficiency and genetic improvement within their herd.

Selected Publications

Clapper, J.A., Ottobre, J.S., Ottobre, A.C. and Zartman, D.L.  1990.  Estrual rise in   body temperature in the bovine I. Temporal relationships with serum patterns of reproductive hormones.  Anim. Reprod. Sci.  23:89-98.

Diekman, M.A., Clapper, J.A., Green, M.L. and Stouffer, D.K.  1991.  Reduction in age of puberty in gilts consuming melatonin during increasing and decreasing daylength.  J. Anim. Sci.  69:2524-2531.

Andres, C.J., Green, M.L., Clapper, J.A., Cline, T.R. and Diekman, M.A.  1991.  Influence of daily injections of porcine somatotropin on growth, puberty and reproduction in gilts.  J. Anim. Sci. 69:3754-3761.

Diekman, M.A., Brandt, K.E., Green, M.L., Clapper, J.A. and Malayer, J.R.  1992.  Lack of a nocturnal rise of serum melatonin in prepubertal gilts.  Dom. Anim. Endocrinol.  9(2):161-167.

Andres, C.J., Green, M.L., Clapper, J.A., Cline, T.R. and Diekman, M.A. and Thomford, P.J.  1993.  Influence of porcine somatotropin on endocrine and histological variables in gilts.  J. Anim. Sci. 71:1552-1560.

Diekman, M.A., Scheidt, A.B., Sutton, A.L., Green, M.L., Clapper, J.A., Kelly, D.T. and Van Alstine, W.G.  1993.  Growth and reproductive performance of gilts infected naturally with pneumonia and atrophic rhinitis during exposure to ammonia.  Am. J. Vet. Res. 54:2128-2131.

Clapper, J.A., Green, M.L., Diekman, M.A.  1993.  Serum concentrations of immunoactive and bioactive LH in gilts. I. Biopotency of LH increases during prepubertal development.  Biol. Reprod. 49:750-756.

Clapper, J.A., Green, M.L., Diekman, M.A.  1993.  Serum concentrations of immunoactive and bioactive LH in gilts. II. Biopotency of LH increases at puberty but remains constant throughout the estrous cycle.  Biol. Reprod. 49:757-763.

Green, M.L., Clapper, J.A., Andres, C.J. Diekman, M.A.  1996.  Serum concentrations of melatonin in prepubertal gilts exposed to either constant or stepwise biweekly alteration in scotophase.  Dom. Anim. Endocrinol. 13:307-323.

Diekman, M.A., Arthington, J.A., Clapper, J.A., Green, M.L.  1997.  Failure of melatonin implants to alter onset of puberty in gilts.  Anim. Reprod. Sci. 46:283-288.

Clapper, J.A., Snyder, J.L., Roberts, A.J., Hamernik, D.L., Moss, G.E.  1998.  Estradiol increases relative amounts of insulin-like growth factor binding protein-2 in serum and expression of insulin-like grwoth factor binding protein-2 in anterior pituitaries of ewes.  Biol. Reprod. 59:124-130.

Snyder, J.L., Clapper, J.A., Roberts, A.J., Sanson, D.W., Hamernik, D.L., Moss, G.E.  1999.  Insulin-like growth factor-I, insulin-like growth factor-binding proteins, and gonadotropins in the hypothalamic-pituitary axis and serum of nutrient–restricted ewes.  Biol. Reprod. 61:219-224.

Juengel, J.L., Melner, M.H., Clapper, J.A., Turzillo, A.M., Moss, G.E., Nett, T.M., Niswender, G.D.  1998.  Steady-state concentrations of mRNA encoding two inhibitors of protein kinase C in ovine luteal tissues.  J. Reprod. Fert. 113:299-305.

Turzillo, A.M., Clapper, J.A., Moss, G.E., Nett, T.M.  1998.  Regulation of ovine GnRH receptor gene expression by progesterone and estradiol.  J.  Reprod. Fert. 113:251-256.

Green, M.L., Clapper, J.A., Diekman, M.A.  1999.  Serum concentrations of melatonin during scotophase and photophase in 3, 4, 5, and 6 month old gilts and barrows.  J. Reprod. Sci. 57:99-110.

Clapper, J.A., Clark, T.M., Rempel, L.A.  2000.  Serum concentrations of IGF-I, estradiol-17b, testosterone, and relative amounts of IGF binding proteins (IGFBPs) in growing boars, barrows, and gilts.  J. Anim. Sci. 78:2581-2588.

Pesall, J.E., McFarland, D.C., McMurtry, J.P., Clapper, J.A., Francis, G.L., Gilkerson, K.K.  2001.  The effect of insulin-like growth factor analogs on turkey satellite cell and embryonic myoblast proliferation.  J. Poultry Sci. 80:944-948.

Lado-Abdeal, J., Clapper, J.A., Norman, R.L.  2001.  Antagonism of central vasopressin receptors blocks hypoglycemic stress induced inhibition of LH release in male rhesus macaques.  J. Neuroendocrinol.13(7):650-655.

Lado-Abdeal, J., Clapper, J.A., Zhu, B.C., Hough, C.M., Syapin, P.J., Norman, R.L.  2001.  Hypoglycemia-induced suppression of luteinizing hormone secretion in intact female rhesus macaques: Role of vasopressin and endogenous opioids.  Stress. (In Press).

Bok, J.M., Wulf, D.M., Clapper, J.A., Thaler, R.C., Maddock, R.J.  2001.  Effects of high protein/low carbohydrate swine diets during the final finishing phase on pork muscle quality.  J. Anim. Sci. (In Press).

Clapper, J.A., Rempel, L.A.  2001.  Feed restriction of prepubertal gilts increases anterior pituitary gland (AP) responsiveness to GnRH but does not affect AP concentrations of IGF-I or IGF finding proteins (IGFBPs).  Biol. Reprod. 64 (Suppl. 1):374.

Rempel, L.A., Clapper, J.A.  2002.  Administration of estradiol-17b increases anterior pituitary IGF-I and relative amounts of serum and anterior pituitary IGF binding proteins (IGFBP) in barrows.  J. Anim. Sci. 80:214-224..

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