Brief Summary of Minutes of Annual Meeting

The meeting was called to order at 8 am on Thursday, May 29, 2003 by Chair Adele Turzillo (AZ). Meeting participants introduced themselves, and the minutes of the last meeting were approved. Colin Kaltenbach (AZ), administrative advisor, pointed out that we were in the middle of the current project cycle. He also further discussed the electronic format for the meeting minutes, and following general discussion, it was decided that a full-set of minutes would be posted on the W112 list-serve. Deb Hamernik (USDA-CSREES) provided a handout with news and updates regarding personnel, budgets and funding opportunities at USDA. Included in this information is the plan for the NRI to move to electronic submission and the 5-year strategic plan. Dr. Hamernik also discussed the CSREES budget and the recent request for supplemental applications by the NRI.The business meeting began at 9:00 am, by thanking Dale Holcombe for making the local arrangements in Reno, NV. Andy Roberts (USDA-ARS, Miles City, MT) was elected as the Member-at-Large for 2004. Discussion then focused on where to hold the 2004 meeting. Sites that were suggested included Reno, NV, Las Vegas, NV, Tucson, AZ and Davis, CA. After considerable discussion, it was moved (Dennis Hallford) and seconded (Todd Hansen) that the meeting be held in Las Vegas, NV. Following additional discussion about the dates, it was voted on and passed that the 2004 W112 meeting will be held May 24 and 25, 2004 in Las Vegas, NV. Adelle Turzillo volunteered to take charge of the local arrangements.

As old business, Mike Day (Ohio) discussed the status of the estrous synchronization training manual. As a training manual, it is complete but does not include any discussion on the costs of the various treatment protocols. After discussion, it was decided to include a range of cost for each protocol, and the document would be complete. Dr. Day asked the W112 members to review the document as is, such that after a final edit the document could be placed on the list-server. Additional discussion focused on where to publish the document. It was decided that this training manual on estrous synchronization was best suited for electronic publication.

In additional old business, Jim Berardinelli (MT) discussed the server problems he has been faced with in operating the W112 web site. These problems should soon be rectified, allowing the web site to be updated into a useful format.

The remainder of the meeting was devoted to presentations and discussions of individual station reports. Discussions and arrangements for station-to-station collaborations during the 2003-2004 year were made. These planned collaborations were recorded and submitted to Secretary Russ Anthony (CO), who will compile them and make them available to the members via the list-server.

Ovarian Biology:
1. Gonadal Development
Bovine testicular cells cultured for up to 3 weeks as dispersed cells on a bovine embryonic fibroblast feeder layer can colonize recipient nude mouse testes suggesting spermatogonial stem cell survival. Bovine testicular tissue explants cultured for up to 3 weeks have increased germ cell proliferation compared to controls. Germ cells from bovine testicular explants can colonize recipient nude mouse testes and the number of colonization competent cells increases from 1-3 wk of culture.

Ovarian maturation is accelerated in heifers that are weaned early and fed a high concentrate diet, resulting in increased diameter of dominant follicles and precocious onset of puberty. Weaning at 3 months of age did not accelerate puberty relative to heifers that were suckling their dams to 7 months; if body weight gains were similar.

2. Follicular Development
When estradiol is used to initiate follicle atresia, timing of emergence of the next wave of ovarian follicles is dependent upon dosage of estradiol administered, rather than timing of atresia. During estradiol induced atresia, rapid reductions in intrafollicular estradiol concentrations are accompanied by reductions in mRNA for aromatase, and to a lesser extent for 17a hydroxylase and mRNA for LHR, FSHR, Fas and Fas  Ligand are unchanged at 24 h after estradiol treatment.

Fasting prior to proestrus influenced ovarian follicular dynamics and the ability of
Developing follicles to secrete estradiol. Feeding fats high in linoleic acid did increase the formation of ovarian follicles in postpartum anestrous cows.

Premature ovulation of a dominant follicle results in decreased ovulatory size, reduced luteal function and compromised conception rates, compared to animals induced to ovulate a larger, more mature dominant follicle and in animals that spontaneously ovulate.

3. Sexual Behavior
The volume of the ovine sexually dimorphic nucleus (oSDN) corresponds to the type of sexual partner preference exhibited by rams. SDN volume for female-oriented rams (FORs) is greater than for male-oriented rams (MORs) and neurons for the SDN express high levels of aromatase mRNA with greater expression in FORs than in MORs and ewes. This further implies that the brains of MORs are incompletely masculinized and support the hypothesis that naturally occurring variations in sexual partner preference are determined by underlying biological mechanisms.

The LH surge mechanism was operational in 4 of 4 ovariectomized ewes, 3 of 4 castrated male-oriented rams (MORs) and 0 of 4 castrated female-oriented rams (FORs). Peak serum LH concentrations, latency, or duration of the estradiol-induced surge response were not significantly different between ewes and MORs. However, LH in ewes and MORs were greater than in FORs during the interval of the surge. These results indirectly support the hypothesis that MORs are incompletely androgenized/masculinized with the MORs exhibiting a neuroendocrine LH response similar to ewes. The response of MORs to estrogen might serve as the basis for future development of a practical test that can be used by producers to identify these animals.

Restraint stress increased cortisol and decreased testosterone similarly in both low and high libido rams and consequently does not provide a method of differentiating such rams by level of libido.

Based on behavioral observation data alone, low libido rams were approximately 50% as efficient and male-oriented rams approximately 75% as efficient as high libido rams at mating ewes in a competitive mating environment.

Present findings show that active immunization against an inhibin a-subunit peptide neither advanced puberty nor increased sperm production in ram lambs. On the contrary, it decreased LH and testosterone secretion and delayed the onset of puberty. A better understanding of underlying inhibin physiology may lead to the development of an inhibin immunogen and immunization protocol that consistently increases FSH secretion in ram lambs. If so, the approach would need to be reassessed for effects on the onset and rate of sperm production.

4. Ovulation
Short-term fasting increased body weight loss and time from PGF2a to ovulation, suggesting an influence of short-term fasting on time of ovulation.

5. Luteal Function
Our data suggest nitric oxide (NO) is not luteolytic in cattle and that estrous synchronization affects response of bovine luteal tissue to agonists or antagonists of prostaglandin secretion indicating a better understanding of the effects of estrous synchronization on luteal function are needed to optimize positive effects of estrous synchronization.

Messenger RNA encoding induced nitric oxide synthase (NOS) differed, and endothelial NOS tended to be altered, in response to PGF2a, suggesting that PGF2a may regulate amounts of mRNA encoding NOS in the bovine CL.

Overexposure of the developing bovine corpus luteum to LH is detrimental for luteal production of oxytocin and progesterone. It is possible that initial stimulation of small luteal cells by LH causes these cells to produce a paracrine factor that acts upon the large luteal cell to impair their function.


6. Environmental Control
Our finding that the EBA agent does not appear to be able to produce abortions in sheep, should be of use to sheep producers whose grazing ranges contain Ornithodorus coriaceus. Their sheep production is not affected by the presence of the tick, even if a portion of endemic ticks are infected with the EBA agent. Probes and methods developed to detect the presence of the EBA agent in animal tissues and ticks are reliably able to detect the EBA agent in ticks.

The results of studies conducted during the past year indicate that stress, or stress-like levels of cortisol, interrupt follicular development and ovulation in sheep. The anti-gonadal effect of cortisol is due, at least in part, to cortisol- dependent reduction in GnRH receptor expression in pituitary tissue.

Transportation stress results in an increase followed by a gradual suppression of anterior pituitary secretion of ACTH accompanied by a decrease in anterior pituitary responsiveness to corticotropin releasing factor and arginine vasopressin stimulation.

Testicular and epididymal sperm content and daily sperm production of tropically-adapted Bos taurus bulls are more similar to tropically-adapted Bos indicus bulls than to temperate Bos taurus bulls raised in the subtropics during late spring and summer.

Temperament of an animal can have an influence on reproductive performance. Measuring exit velocity from a chute seems to be a better measurement than temperament scoring systems. The temperament of the dam is strongly associated with temperament of the calf.

Brahman cows tend to have greater concentrations of metabolic hormones relative
to Angus cows and these concentrations may be sensitive to seasonal dynamics of
forage quality in the Chihuahuan Desert.

Uterine Biology:

1. Maternal Recognition of Pregnancy


Sheep oviduct specific protein (OSP) mRNA is expressed only in cells of the ampulla (AMP) but is present in the apical portions of cells of the isthmus (IST). Surprisingly, we found sOSP in the AMP and IST, and mRNA for sOSP in the AMP of prepubertal ewe lambs.

The bovine ISG15 E1 has been partially sequenced to confirm identity. This enzyme is the first of several that dictate specific conjugation of ISG15 to targeted proteins.

2. Placental/Fetal Development

While alterations in uterine blood flow and oxygenation of the pregnant uterus may play a role in the etiology of hyperthermia-induced placental insufficiency leading to fetal growth restriction (FGR), our results indicate that hypoxia alone cannot account for the observed changes in placental vascularization.

The results of experiments with nuclear transfer (NT)-cloned bovine pregnancies strongly suggests placental involvement in the birth of large calves for both IVF and NT procedures. Heretofore, the embryo/fetus itself is a primary focus of the problem.

Modulators of cellular calcium signalling pathways given alone do not affect placental progesterone secretion. Progesterone receptor-mediated events appear to suppress placental PGF2a secretion and progesterone receptors may play a role in placental secretion of progesterone in cattle. PGE2 does not appear to regulate placental progesterone secretion in cattle.


3. Mastitis Control

A subclinical mastitis infection caused by S. aureus does not influence systemic concentrations of IGF-1 and T3, although the local infection increased serum cortisol and decreased T4 concentrations within the first 36 hours following infection. Serum IgG was not affected by either amoxicillin or Mastfrigao treatment or S. aureus infection. In contrast, milk IgG concentrations were greater in NCG compared to all other treatments by hour 48, indicating that treatments used for subclinical mastitis had a direct effect on milk IgG concentrations.

Reproductive Technology:

1. Immunocastration

Immunization against recombinant fusion proteins of both LHb and LHRH was not beneficial in inducing sterility in beef heifers. Results of our most recent experiment would suggest focusing on the LHRH antigen alone.

A field study in Brazil with an LHRH immunocastration protocol is in progress. The vaccine causes a significant reduction in scrotal circumference when compared to intact controls. One hundred days after the last immunization seventy-three bulls from one of the ranches were sent to slaughter. Intact bulls had higher carcass weights and muscle percentage compared to the other two groups. Castrated and immunized animals had greater marbling and fat percentages than intact bulls.

2. Assisted Reproductive Technologies

Using a week-long MGA feeding period prior to a GnRH-PGF synchronization system resulted in a relatively high pregnancy rate relative to previously reported results for timed A.I. trials

Progestins differ in their ability to induce estrous cycles in postpartum anestrous beef cows. Administration of progesterone for 7 days with a CIDR induced ovulation and estrous cycles in postpartum anestrous beef cows, but neither the normal dose (0.5 mg/d) nor a high dose (4 mg/d) of MGA induced ovulation or estrous cycles.


Exposing cows to bull or excretory products of bulls did not alter the breeding performance of first-calf restricted suckled beef cows using a modified CO-Synch protocol. However, physical presence of a bull may enhance breeding performance of cows bred at timed AI in this protocol.

Ewes receiving a CIDR on d 0 have the same P4 on d 12 to 14 as CIDR-treated OVX ewes suggesting premature demise of the corpus luteum which may adversely impact conception rate. Progesterone from CIDRs rapidly enters the circulation (within 1 h) at the time of insertion and is rapidly cleared after CIDR removal (< 1ng/mL by 1 h). After 2, 15-d periods in situ, CIDRs were no longer able to increase serum P4 concentrations.

Early weaning fails to improve reproductive performance of red deer females. This may be related to the strong seasonality of this species and the possible male effect from the stag.

Our research demonstrates the effectiveness of using modified cattle CIDRs for estrous synchronization in muskox cows. In addition, our results illustrate an interaction of bull exposure and CIDR in the timing of the synchronized estrus.

Our group has previously shown radiotelemetry to be a reliable and accurate means of detecting estrus in muskoxen but our recent results indicates radiotelemetric technology is less effective with reindeer.

Alexander, B.M., B.W. Hess, D.L. Hixon, B.L. Garrett, D.C. Rule, M. McFarland, J.D. Bottger, D.D. Simms and G.E. Moss. 2002. Influence of fat supplementation on beef cow reproduction and calf performance. Prof. Animal Scientist. 18:351-357.

Amstalden M, Garcia MG, Stanko RL, Nizielski SE, Morrison CD, Keisler DH, Williams
GL. 2002. Central infusion of recombinant ovine leptin normalizes serum insulin and
stimulates a novel luteinizing hormone hypersecretion after short-term fasting in ovariectomized cows. Biol Reprod 66:1555-1561.

Bailey MT, Troedsson MHT, JE Wheaton. 2002. Inhibin concentrations in mares with
granulosa cell tumors. Theriogenology 57: 1885-1895.

Baker, D.L., M.A. Wild, M.M. Conner, H.B. Ravivarapu, R.L. Dunn and T.M. Nett. 2002.
Effects of GnRH agonist (leuprolide) on reproduction and behaviour in female wapiti
(Cervus elaphus nelsoni). Reproduction, Suppl. 60:155-167.

Bertolini, M., S.E. Beam, H. Shim, L.R. Bertolini, A.L. Moyer, T.R. Famula and G.B. Anderson. 2002. Growth, development and gene expression by in vitro-and in vitro-produced day-7 and day-16 bovine embryos. Molecular Reproduction and Development 63:318-328.

Bertolini, M., J.B. Mason, S.E. Beam, G.F. Carneiro, M.L. Sween, D.J. Kominek, A.L. Moyer, T.R. Famula, R.D. Sainz and G.B. Anderson. 2002. Morphology and morphometry of in vitro-and in vitro-produced concepti from early pregnancy to term and association with high birth weights. Theriogenology 58:973-994.

Bispham, J., Budge, H., Mostyn, A., Dandrea, J., Clarke, L., Keisler, D.H., Symonds, M.E.
and Stephenson T. 2002. Ambient temperature, maternal dexamethasone, and postnatal
ontogeny of leptin in the neonatal lamb. Pediatric Research 52, 85-90.

Bottger, J. D., B. W. Hess, B. M. Alexander, D. L. Hixon, L. F. Woodward, R. N. Funston, D. M. Hallford, and G. E. Moss. 2002. Effects of supplementation with high linoleic or oleic cracked safflower seeds on postpartum reproduction and calf performance of primiparous beef heifers. J. Anim. Sci. 80:2023-2030.

Boutinaud M, Rulquin H, Keisler DH, Djiane J, Jammes H. 2002. Use of somatic cells from goat milk for dynamic studies of gene expression in the mammary gland. J Anim Sci 80:1258-1269.

Buff PR, Dodds AC, Morrison CD, Whitley NC, McFadin EL, Daniel JA, Djiane J and
Keisler DH. 2002. Leptin in horses: tissue localization and relationship between peripheral concentrations of leptin and body condition J. Anim Sci 80:2942-48.

Cupp AS, L Tessarollo, and MK Skinner. 2002. Testis development phenotypes in neurotropin receptor trkA and trkC null mutations: Role in seminiferous cord formation and germ cell survival. Biol. Reprod 66:1838-1845.

Cupp AS, M Uzumcu and MK Skinner. 2003. Effect of AG879 a trk specific tyrophostin inhibitor on mesonephric cell migration during seminiferous cord formation in the rat. Biol Repro 68:2033-37.

Daniel JA, Whitlock BK, Baker JA, Steele B, Morrison CD, Keisler DH, Sartin JL. 2002. Effect of body fat mass and nutritional status on 24-hour leptin profiles in ewes. J Anim Sci 80:1083-1089.

DeJarnette, J.M., M.L. Day, R.B. House, R.A. Wallace and C.E. Marshall. 2001. Effect of GnRH pretreatment on reproductive performance of postpartum suckled beef cows following synchronization of estrus using GnRH and PGF2a. J. Anim. Sci. 79:1675-1682.

Denniston, D. J., M. G. Thomas, K. K. Kane, C. N. Roybal, L. Canales, D. M. Hallford,
M. D. Remmenga and D. E. Hawkins. 2003. Effect of neuropeptide Y on GnRH
induced LH release from bovine anterior pituitary cell cultures derived from heifers in a
follicular, luteal or ovariectomized state. Anim. Reprod. Sci. 78:25-31.

de Vrijer, B., T.R.H. Regnault and R.V. Anthony. 2003. Understanding fetoplacental
growth through transgenic IGF models. Ped. Res. 53:537-538.

Funston, R. N., T. W. Geary, R. P. Ansotegui, R. J. Lipsey, and J. A. Paterson. 2002.
Supplementation with whole sunflower seeds before artificial insemination in beef
heifers. Prof. Anim. Sci. 18:254-257.

Garcia MR, Amstalden M, Williams SW, Stanko RL, Morrison CD, Keisler DH, Nizielski
SE, Williams GL. 2002. Serum leptin and its adipose gene expression during pubertal
development, the estrous cycle, and different seasons in cattle. J. Anim. Sci. 80:2158-
2167.

Geary, T. W., E. L. McFadin, M. D. MacNeil, E. E. Grings, R. E. Short, R. N. Funston,
and D. H. Keisler. 2003. Leptin as a predictor of carcass composition in beef cattle. J.
Anim. Sci. 81:1-8.

Groothuis,P.G., W.J. McGuire, J.L. Vallet, D.M. Grieger and D.L. Davis. 2002. Retinol and Estradiol Regulation of Retinol Binding Protein and Prostaglandin Production by Porcine Uterine Epithelial Cells In Vitro. J. Anim. Sci. 80(10):2688-94.

Hernandez, J. A., D. M. Hallford, and N. H. Wells. 2003. Ovarian cyclicity in thyroid-
suppressed ewes treated with propylthiouracil immediately before onset of seasonal anestrus. J.Anim. Sci. 81:29-34.

Hicks, B.A., Yankey, S.J., Carnahan, K.G., Joyce, M.M., Assiri, A.M., Sinor, S.J., Kodali, K., Johnson, G.A., Hansen, T.R., Mirando, M.A., Woods, G.L., Vanderwall, D.K. and Ott, T.L. 2003. Expression of the uterine Mx protein in cyclic and pregnant cows, gilts, and mares. J. Anim. Sci. 81:1552-1561.

Johnson. G.A., M.M. Joyce, S.J. Yankey, T.R. Hansen, and T.L. Ott. 2002. The Interferon Stimulated Genes (ISG) 17 and Mx have different temporal and spatial expression in the ovine uterus suggesting more complex regulation of the Mx gene. J Endocrinol. 174:R7-R11.

Kane, K. K., K. W. Creighton, M. K. Petersen, D. M. Hallford, M. D. Remmenga, and D. E. Hawkins. 2002. Effects of varying levels of undegradable intake protein on endocrine and metabolic function of young post-partum beef cows. Theriogenology 57:2179-2191.

Kayser, J.P., P.J. Chenoweth, D.L. Davis, D.M. Grieger, J.C. Samper and M.J. Arns. 2002. The effects of uterine cell-spermatozoa co-culture on the interactions between de-novo secreted and synthesized uterine proteins and stallion spermatozoa. Theriogenology 58: 363-366.

Koster, H.H., B.C. Woods, R.C. Cochran, E.S. Van Zant, E. C. Titgemeyer, D.M. Grieger, K.C. Olson and G. Stokka. 2002. Effects of increasing proportions of supplemental nitrogen from urea in prepartum supplements on range beef cow performance and on forage intake and digestibility by steers fed low quality forage. J. Anim. Sci. 80(6):1652-1662.

Kubotsu, S.L., Hu, J., Carnahan, K.G., deAvila, J., Ott, T.L. and Mirando, M.A. 2003. The effects of chronic ethanol consumption during early pregnancy on conceptus health and uterine function in pigs. Alcoholism: Clinical and Experimental Research 27:712-719.

Li Y, Friel PJ, Robinson MO, McLean DJ, Griswold MD. 2002. Identification and
characterization of testis-/epididymis-specific genes: cystatin SC and Cystatin TE-1.
Biol Reprod, 67:1872-1880.

Lopez, H., T.D. Bunch and M.P. Shipka. 2002. Estrogen concentrations in milk at estrus and ovulation in dairy cows. Anim. Reprod. Sci. 72:37-46.

Lopez, H. and M.P. Shipka. 2003. Association of flooring surface to estrous behavior in lactating dairy cows as determined by radiotelemetric estrous detection. Proceedings of the Fifth International Conference on Dairy Cattle Housing. 5: 265-273.

McFadin EL, Morrison CD, Buff PR, Whitley NC, Keisler DH. 2002. Leptin levels in peri-
parturient ewes and their subsequent offspring. J Anim Sci 80:738-743.

McLean DJ, Friel PJ, Pouchnik D, Griswold MD. 2002 Oliogonucleotide microarray
analysis of gene expression in FSH-treated rat Sertoli cells. Mol. Endo 16:2780-2792.

McLean DJ, Russell LD, Griswold MD. 2002. Biological activity and enrichment of
spermatogonial stem cells in VAD and hyperthermia exposed testes from mice based
on colonization following germ cell transplantation. Biol Reprod, 66:1374-1379.

Morrison CD, Wood R, McFadin-Buff EL, Whitley NC, Keisler DH. 2002. Effect of intravenous infusion of recombinant ovine leptin on food intake and serum concentrations of GH, LH, insulin, IGF-I, cortisol, and thyroxine in growing prepuberal ewe lambs. Dom Anim Endo 22:103-112.

Mostyn A, J. Bispham, S. Pearce, Y. Evens, M. C. Alves-Guerra, C. Pecqueur, B. Miroux,
A. Gertler, D. H. Keisler, R. Webb, T. Stephenson And M. E. Symonds. 2002. Differential
effects of leptin on thermoregulation and uncoupling protein abundance in the neonatal
lamb. FASEB J 16:1438-1440.

Nett, T.M., A.M. Turzillo, M. Baratta, and L.A. Rispoli. 2002. Pituitary effects of steroid
hormones on secretion of follicle-stimulating hormone and luteinizing hormone.
Dom. Anim. Endocrinol. 23:33-42, 2002.

Oatley, JM, DM de Avila, DJ McLean, MD Griswold, and JJ Reeves. 2002.
Transplantation of bovine germ cells into mouse testes. J. Anim. Sci, 80:1925-31.

Obeidat, B. S., M. G. Thomas, D. M. Hallford, D. H. Keisler, M. K. Petersen, W. D. Bryant, M.D. Garcia, L. Narro, and R. Lopez. 2002. Metabolic characteristics of multiparous Angus and Brahman cows grazing in the Chihuahuan Desert. J. Anim. Sci. 80:2223-2233.

ORourke, K.I., J.V. Duncan, J.R. Logan, A.K. Anderson, D.K. Norden, E.W. Williams, B.A. Combs, R.H. Stobart, G.E. Moss and D.L. Sutton. 2002. Active surveillance for scrapie utilizing third eyelid biopsy and genetic susceptibility testing in flocks of sheep in Wyoming. Clin. Diag. Lab. Immunol. 9:966-971.

Parthasarathy V, Price EO, Orihuela A, Dally MR, Adams TE. 2002. Passive immunization of rams (Ovis aries) against GnRH: effects on antibody titer, serum concentrations of testosterone, and sexual behavior. Anim Reprod Sci. 71:203-15.

Paslay, E.M., J.R. Jaeger, U. Salli and F. Stormshak. 2003. Ovarian function in ewes
after treatment with mifepristone early during the oestrous cycle. Reproduction 125:205-
210.

Price EO, Adams TE, Huxsoll CC, Borgwardt RE. 2003.Aggressive behavior is reduced in bulls actively immunized against gonadotropin-releasing hormone. J Anim Sci. 81:411-5.

Rasor, C. C., M. G. Thomas, R. M. Enns, H. C. Salazar, H. M. Zang, G. L. Williams, R.
L. Stanko, R. D. Randel and J. Rios. 2002. Allelic and genotypic frequencies of the
leptin gene Sau3A1-restriction fragment length polymorphism and evaluation of its
association with age at puberty in cattle in the Southwestern United States and Northern
Mexico. Prof. Anim. Sci. 18:141-146.

Regnault, T.R.H., B. deVrijer and R.V. Anthony. 2002. The IGF-II-deficient placenta:
aspects of its function. Trends in Endocrinol. Metabol. 13:410-412.

Rhodes, F.M., C.R. Burke, B.A. Clark, M.L. Day and K.L. Macmillan. 2002. Effect of treatment with progesterone and oestradiol benzoate on ovarian follicular turnover in postpartum anoestrus cows and cows which have resumed oestrous cycles. Anim. Reprod. Sci. 69:139-150.

Rivera, J. D., G. C. Duff, M. L. Galyean, D. M. Hallford, and T. T. Ross. 2003. Effects of graded levels of vitamin E on inflammatory response and evaluation of methods of delivering supplemental vitamin E on performance and health of beef steers. Prof. Anim. Scientist 19:171-177.

Roselli, C.E., F. Stormshak, J.N. Stellflug and J.A. Resko. 2002. Relationship of serum
testosterone concentrations to mate preference in rams. Biol Reprod. 67:263-268.

Roselli, C.E., J.A. Resko and F. Stormshak. 2003. Estrogen synthesis in fetal sheep brain: Effect of maternal treatment with an aromatase inhibitor. Biol. Reprod. 68:370-374.

Sanders S, Cuneo SP, Turzillo. 2002. Effects of nicotine and cotinine on bovine theca interna and granulosa cells. Repro. Toxicology 6:795-800.

Shipka, M.P., J. E. Rowell and S.P. Ford. 2002. Reindeer bull introduction affects the onset of the breeding season. Anim. Reprod. Sci. 72:27-35.

Silva, LF, M.J. VandeHaar, M.S. Weber-Nielsen and G.W. Smith. 2002 Evidence for a
local effect of leptin in bovine mammary gland. Journal of Dairy Science: 85:3277-3286.

Snowder, G.D., Stellflug, J.N., and Van Vleck, L.D. 2002. Heritability and repeatability of sexual performance. J. Anim. Sci. 80:1508-1511.

Stellflug, J.N. 2002. Use of naloxone challenge to predict sexual performance of rams before the fall breeding season. Theriogenology. 58:123-134.

Stellflug, J.N. 2002. Influence of classification levels of ram sexual activity on spring breeding ewes. Anim. Reprod. Sci. 70:203-214.

Stellflug, J.N., and Berardinelli, J.G. 2002. Ram mating behavior after long-term selection for reproductive rate in Rambouillet ewes. J. Anim. Sci. 80:2588-2593.

Stott, J.L., M.T. Blanchard, M. Anderson, M. Mass, R. Walker, P.C. Kennedy, B.R. Norman, R.H. BonDurant, M.N. Oliver, D. Hanks and M.R. Hall. 2002. Experimental transmission of epizootic bovine abortion (foothill abortion) and preliminary classification of the etiologic agent. Vet Micro. 88:161-173.

Vetter DE, Li C, Zhao L, Contarino A, Liberman MC, Smith GW, Marchuk Y, Koob GF,
Heinemann SF, Vale W, Lee KF. 2002. Urocortin-deficient mice show hearing
impairment and increased anxiety-like behavior. Nat Genet 31:363-369.

Weems, Y. S., L. Kim, V. Humphreys, V. Tsuda, and C. W. Weems. 2003. Effect of luteinizing hormone (LH), pregnancy specific protein B (PSPB), or arachidonic acid (AA) on ovine endometrium of the estrous cycle or placental secretion of prostaglandins E2 (PGE2), prostaglandin F2 a (PGF2 a), and progesterone in vitro by corpora lutea of pregnancy or the estrous cycle. Prostaglandins and Other Lipid Mediators. 71:55-73.

Weems, Y. S. , A. W. Lewis, R. D. Randel, and C. W. Weems. 2002. Effects of prostaglandins E2 and F2 a (PGE2; PGF2 a), trilostane, mifepristone, palmitic acid (PA), indomethacin (INDO), ethamoxytriphetol (MER-25), PGE2+PA, PGF2+PA on secretion of PGE2, PGF2a, and progesterone by bovine corpora lutea of mid-pregnancy in vitro. Chinese Journal of Physiology. 45(4):163-168.

Weems, Y. S., P. J. Bridges, R. G. Sasser, B. R. LeaMaster, and C. W. Weems. 2002. Effects of mifepristone on pregnancy and secretion of progesterone, estradiol-17b, pregnancy specific protein B (PSPB), and prostaglandins E and F2a (PGE; PGF2a) in 90-day intact pregnant sheep/.Prostaglandins and Other Lipid Mediators. 70:195-208.

Wells, N. H., D. M. Hallford, and J. A. Hernandez. 2003. Serum thyroid hormones and
reproductive characteristics of Rambouillet ewe lambs treated with propylthiouracil before puberty. Theriogenology 59:1403-1413.

Willard, S. T., S. J. Jaques, H. R. Vera-Avila and R. D. Randel. 2002. Thyroid hormone
response to thyroid-stimulating hormone and effects on luteinizing hormone secretion in
the ovariectomized cow. J. Anim. And Vet. Adv. 1:174-179.

Willard, S. T., D. A. Neuendorff, A. W. Lewis and R. D. Randel. 2002. A comparison of trans-vaginal artificial insemination procedures for use in commercially farmed deer. Small Rum. Res. 44:135-140.

Willard, S. T. and R. D. Randel. 2002. Testicular morphology and sperm content
relative to age, antler status and season in axis deer stags (Axis axis). Small Rum.
Res. 45:51-60.

Williams GL, Amstalden M, Garcia MG, Stanko RL, Nizielski SE, Morrison CD, Keisler DH. Role of leptin and its central regulation of reproduction in cattle. 2002. Dom Anim Endo 23:339-49.

Wilson, T. W., D. A. Neuendorff, A. W. Lewis and R. D. Randel. 2002. Effect of zeranol
or melengestrol acetate (MGA) on testicular and antler development and aggression in
fallow bucks. J. Anim. Sci. 80:1433-1441.