North Central Regional Committee Meeting On Reproductive .

Economic Impact: Importance of Research to Increase Reproductive Efficiency in Livestock(Statement from NCR-57, pre-1987)To meet the ever-growing needs of the present and projected population for meat andmeat products, a great increase will be required in the number of breeding livestock with presentreproduction efficiency.Reproductive inefficiencies receive little publicity because they are not spectacular, donot pose an immediate threat to human health, and often have been viewed as innate and notsubject to elimination. Losses due to reproductive inefficiency are insidious but very costly.Prolonged generation intervals due to delayed puberty, small numbers of offspring perconception, low conception rates, failure of many breeding animals to reproduce at all,embryonal deaths, and fetal deaths at parturition all contribute to reduced fertility. A disease thateach year killed 25% of the nation’s cattle, sheep, or pigs would command immediate attentionby the press, the consumer, the producer, and those responsible for allocating research funds.The losses from embryonal deaths in the three species mentioned are at least 25% from day ofbreeding to day 25 of gestation. Another 20% of young born die at birth or within a few hoursfrom causes directly attributable to the birth process. Many females have no embryonal loss andhave no loss of fetuses from parturition so these losses are not innate and part of the destiny ofevery animal, these losses are due to some reason. Before cures can be expected, causes andreasons must be established to form a base of knowledge.During the course of the annual meetings of the NCR-57 committee over the past severalyears, discussions by the researchers in reproductive physiology on which of the many facets ofreproductive physiology deserves attention and would be most likely to yield significant results,have led to designating the following areas.Embryonal and Fetal SurvivalEmbryonic mortality is a significant factor in all farm livestock. Embryonic loss reduceslitter size by 30% in swine, occurs in over one-fifth of all fertilized eggs in the sheep and cow,and is a major contributor to the meager 60% hatching rate in the turkey. At the present time,there is no treatment, regimen of diet or management scheme that has consistently improvedembryonal survival. Because this mortality constitutes such a great proportion of total losses, itmerits much greater research emphasis. Even slight increases in embryonal survival would havea tremendous impact on the reproductive efficiency of the nation’s livestock.Control of OvulationMethods of controlling ovulation have been developed but remain unavailable because oflow conception in some species or regulatory agencies have not approved their general use inother species.Acceptable control of ovulation would embody the following characteristics: fertility atcontrolled ovulation would be as great as normal or greater; control would be precise soinseminations would be done by appointment; safe for both the animal and a potential humanconsumer of the animal; cost should not be prohibitive; administration should be convenient,consistent, and reliable. Control of ovulation is essential to widespread use of artificialinsemination (AI) in domestic livestock. The cost, dedication, and skill necessary to check for11d:Mark/NRC 57 Historical Report 2006

heat accurately and obtain high conception prohibits use of AI except in special circumstances.Insemination at a certain time relative to a controlled time of ovulation has been shown to giveconception rates equal to or above usual levels. Parturition could be controlled and supervisedwhen several members of a breeding herd are at the same stage of pregnancy.Parturition and Post-partum RecoveryDeath loss associated with birth and failure of the mother to mate soon after parturitionaccount for a substantial reduction in reproductive efficiency. Of the 150,000,000 piglets born inthe USA each year, 7% or 10,500,000 are stillborn. These are normal, fully formed fetuses thatwere alive at the beginning of the birth process but are presented dead. These 10,500,000 deathsand other birth-related deaths within the first 48 hours of birth are a complete waste ofreproductive potential.The cow rarely conceives until 60 days after parturition, the sow must be weaned beforemating, and then only after at least a 3 or 4 week lactation, the ewe often is not pregnant for 7 ofthe 12 months in a year. A mouse conceives within 24 hours of birth of the litter and is bothpregnant and lactating most of her life. As daily feed and maintenance costs of breeding animalscontinues to increase so should the emphasis on reducing the number of days that animals in abreeding herd are not pregnant.Gamete and Zygote Storage and HandlingEven though AI and embryo transfer have the potential for reducing the transmission ofdisease between herds, increases the number of offspring from a superior parent and facilitatestransport of genes between farms, states, and continents, they are used relatively infrequently.The proportion of breeding females settled by AI is but a small fraction of the total even in cattleand is especially small in swine and sheep. Further development of the technology for semenpreservation, insemination and for egg and embryo storage and transfer to overcome the presenthindrances to their exploitation needs increased emphasis.At present in the USA about one lamb is produced per ewe per year, less than one calf isproduced per cow per year, and about 12 piglets per sow are produced each year.Reproductive efficiency is quite low. Those areas discussed have tremendous unrealizedpotential for increased productivity. These areas need to be emphasized and supportedfinancially. Students need to be trained in these areas in increasing numbers to take advantage ofthe potential increases possible. Reproductive physiology should not only be a subject ofacademic interest but should be in the forefront of those disciplines with goals of increasedproductivity.12d:Mark/NRC 57 Historical Report 2006

The Impact of NCR-57 Committee on Reproductive Physiology, 1987Since its inception in the early 1960’s, the first as the NCR-26 Committee on SwineArtificial Insemination, and then as NCR-57, the Committee has met at experiment stations on arotating basis. The membership of the Committee has evolved gradually over the years, whileretaining the initial format and emphasis. The annual meetings have served as a very usefulforum for discussion of research just completed but not yet published, preliminary reports and,perhaps most importantly, an exchange of ideas on which to build existing knowledge. Aperusal of early reports, and then followed by a similar examination of recent reports, vividlydemonstrates the magnitude of progress made in understanding and technology that has takenplace. Some of the speed and expediency by which this knowledge has been accumulated is dueto the informal exchange of information and technology that occurs during the annual meetings.Thousands of dollars and research man hours have been saved by the simple process ofdiscussion of research planned or in a yet unpublished stage by a relatively small group. Manyobservations and small but important techniques have been discussed that have saved manyprojects. Unnecessary redundancy has been avoided. The committee serves not only to saveresearch money but to also provide a basis for more profitable and efficient production of animalproducts. Because one aspect of knowledge can be applied to so many units each bit has atremendous impact on the whole. One more pig born per litter in the more than 10,000,000farrowings in the U.S.A. would mean at least 250,000,000 more realized by the livestockproducer or saved by the consumer. The stimulus derived from an open but unpublished forumcarries on after the meeting, both to regular members and to graduate students and other visitors.This atmosphere is much more conducive to open discussion than the relatively fixed and formalone at national society meetings.The problems posed by the Committee and summarized in reports such as this one haveserved as a helpful basis in directing programs that lead to solutions of such problems. Some ofthe impetus for the competitive research grant program the language and the emphasis has comefrom discussions and reports of our annual meeting. The recognition of the importance ofresearch in reproductive physiology and the significance of possible breakthroughs inreproduction in the form of increased financial support has been heartening. The science ofreproductive physiology is relatively new and the potential is very great. Continued andincreased support is readily justified and fully warranted. Because of the diversity ofmechanisms of reproduction by the many useful species, the comparative approach is necessary.The integration of the many steps from gamete production to birth requires a broad view by thescientists. Because of the nature of the subject area, research findings in reproductive physiologycan not only be translated into a gradual accretion of understanding, but often has the potential torevolutionize many aspects of the animal industry. Many of these findings have been firstpresented and discussed at the annual meeting of NCR-57. Our level of understanding andtechnology has changed dramatically in just a few years. One example of the extent of changethat has taken place is the routine collection of embryos at very precise stages of developmentfrom many domestic species. Studies of embryos, transfers, transgenic insertions and nuclearinsertions can now be done as a matter of course. Undergraduate students with little previousexperience can be expected to succeed in recovery of embryos at very specific stages by readingthe recent literature. This has been possible because of studies on the endocrinology, gametephysiology and embryology that have been discussed in NCR-57 meetings. The basic13d:Mark/NRC 57 Historical Report 2006

endocrinology of the estrous cycle and pregnancy are far better understood than even a few yearsago and are beginning to serve as a basis for application to management of animals.We now have a base of understanding that was beyond our comprehension 25 years ago.The potential for increasing this base is even greater than it was. Hopes and dreams of even themost imaginative and innovative researchers have become commonplace and routine. Continuedsupport for programs in reproductive physiology and encouragement in the form of providing asetting conducive to open discussion such as NCR-57 will help make those hopes and dreams areality.There is no certainty that research in any one specific area of reproductive physiologywill always lead to a solution of a problem. Awareness of a problem and possible implicationsand associations make an experienced and observant researcher more likely to recognize apossible solution. There are many questions that still need more complete and satisfactoryanswers. A partial list follows: gamete production, harvesting a greater proportion of oocytespresent; control of oocyte maturation; sperm harvesting; gamete and embryo storage andmanipulation; cloning; transgenic production; prediction of potential fertility and fecundity andidentification of potential fertility; pregnancy detection; control of litter size; appointment ofovulation, both time and numbers; appointment of time of births; understanding influence ofvarious components of the environment on reproduction; selective sterilization of males andfemales, role of various hormones in pituitary and brain function as influenced by theenvironment, seasonality of breeding and birth.NCR-57 has served a very useful purpose in the past; it shows every promise of beingeven more useful in the future. It is not only a good investment in the future, it also provides foran economy of resources in the present. The Committee stands, as always, prepared to provideinput on considered judgment of courses of action and programs for reproductive physiology.14d:Mark/NRC 57 Historical Report 2006

Research Priorities in Animal Reproduction Research for the 1990’sReproduction is the primary factor that limits efficient production of livestock. The goalof research in reproduction is to develop an understanding of these gene products that increasereproductive efficiency in farm animals. Towards this end, the following three areas ofreproduction research need special priority in the 1990’s:1. Neuroendocrine regulation of reproductive cycles and pregnancyEfficient production of livestock involves an understanding of reproductive cycles andhow to manipulate them to the producer’s benefit. There are several phases of reproductivecycles which need further understanding and development of techniques to control them, andto increase fertility and fecundity. Among these are the timing of puberty, ovulation control,control of parturition, and re-establishing fertility during the postpartum anestrous period. Itis crucial to have a clear understanding of the neuroendocrine, environmental factors,behavioral aspects and genes that are involved in control of reproductive cycles, pregnancyand postpartum fertility.2. Production, preservation and manipulation of gametes and embryosResearch in this area should continue to develop and implement the biotechnologies ofgene transfer, in vitro production of embryos, cloning, sex determination of embryos,separation of X and Y sperm and preservation of gametes. To accomplish this, it will beessential to have a basic understanding of how to maximize harvest of gametes, maturation ofsperm and eggs, fertilization, isolation of embryonic stem cells, embryo development andprinciples of cryopreservation. With the development of these biotechnologies will come theopportunity to develop new methods of predicting fertility, gene manipulation andidentification of genes that control key events of reproduction.3. Enhance prenatal and perinatal survivalSubstantial losses and decreased reproductive performance result from decreased prenataland perinatal survival. A key to enhancing survival is a detailed understanding of pre- andpostnatal development that includes the role of uterine secretions, uterine capacity,immunological resistance, environmental factors and identification of regulatory genes andtheir products.Greater understanding of the factors that control reproduction will lead to greaterfecundity, less prenatal losses and greatly increase the number of offspring from superior geneticmaterial. This knowledge is necessary to provide a safe and available food supply to consumersand to increase the international competitiveness of American agriculture.I.Justification for Continuation of the CommitteeNCR-57 includes a diverse group of scientists who conduct research over a wide rangeof topics in reproductive physiology. These topics have been identified as researchpriorities in animal reproductive research for the 1990’s. The areas range from: A)neuroendocrine regulation of reproductive cycles and pregnancy, B) production,preservation and manipulation of gametes and embryos and C) enhancement of prenataland perinatal survival. At the annual meeting, the group discusses and critiques research15d:Mark/NRC 57 Historical Report 2006

projects in an informal setting. Valuable suggestions for improvement of the quality of theresearch and opportunities for collaboration between scientists at different stations haveresulted. The wide range of topics discussed at the annual meeting are invaluable forresearchers in different areas to keep abreast of the current developments in fields that theythemselves are not investigating. NCR-57 spent considerable time in drafting a descriptionof research priorities for the 1990’s (see attached) which was requested by CSRS for use inthe competitive grants program and submitted to Dr. Gray on September 24, 1990. Theaccomplishments and activities of NCR-57 that include both formal and informalcollaboration are exemplary as noted by the numerous publications from 1989-91. Werequest that NCR-57 be extended for another three year term starting October 1, 1992.II.Committee Objectives1. To develop an understanding of those gene products that increase reproductiveefficiency in farm animals.2. To apply the recent discoveries in understanding reproductive processes intodevelopment of new or improved technologies for the livestock industry.3. To promote scientific exchange and critique at the annual meeting, improve the qualityof research conducted, minimize duplication of research effort, and especiallyencourage cooperation and collaboration among scientists at different institutions.4. To facilitate more rapid transfer of knowledge into teaching and extension programsthrough exchange of findings from diverse areas of reproductive physiology research.5. To inform research administrators and others of research accomplished by members ofNCR-57 by preparation and distribution of an annual proceedings.III.States and Active ParticipantsSee Appendix I.IV. Highlights of Committee Activities and Accomplishments Since the Last ApprovalA. Formal areas of collaborative research efforts with joint publication of results.1. Hypothalamic regulation of pituitary secretion and resulting corpora luteal function inpigs. (USDA-MARC, J. Klindt, J.J. Ford, USDA-BARC, D.J. Bolt; Iowa StateUniversity, L.L. Anderson; Total publications: 5)2. Superovulation with FSH and HMG in cattle (USDA-MARC, R.R. Maurer; Iowa StateUniversity, L.L. Anderson; Total publications: 1)3. Endocrine changes in compensatory testicular and epididymal growth (USDA-BARC;D.J. Bolt; University of Minnesota, B.G. Crabo; Total publications: 2)4. Activation of porcine oocytes for nuclear transfer (University of Wisconsin, N.L. First;Pennsylvania State University, D.R. Hagen; University of Missouri-Columbia, R.S.Prather; Total publications: 1)16d:Mark/NRC 57 Historical Report 2006

5. Effect of relaxin on cervical dilation and fertility in the postpartum ewe (University ofMissouri-Columbia, B.N. Day; Lincoln University, S. Meredith; Total publications: 2)6. Estrous synchronization of the postpartum ewe (University of Missouri-Columbia, B.N.Day; Lincoln University, S. Meredith; Total publications: 1)7. Variation in ovulation time course and embryogenesis in swine (Ohio State University,W.F. Pope; Oklahoma State University, R.D. Geisert; Total publications: 1)8. Induction of estrus in prepuberal gilts (Illinois State University, S.K. Webel; Universityof Missouri-Columbia, B.N. Day; Total publications: 1)B. Research with common areas of interest by two or more institutions, wherecooperation, although less formal, occurs. A summary of the projects and investigatorsis listed below. A complete list of the publications is presented in Appendix III.1. Neuroendocrine regulation of reproductive cycles and pregnancya. Timing of puberty: Illinois State University, S.K. Webel; Purdue University, M.A.Diekman; Iowa State University, L.L. Anderson; Kansas State University, D.L.Davis; Michigan State University, H.A. Tucker; University of Minnesota, B.G.Crabo; University of Missouri, B.N. Day; Lincoln University, D.B. Killian, S.Meredith; University of Nebraska, D.W. Zimmerman; Pennsylvania State University,D.R. Hagen; South Dakota State University, R. Hanson; USDA-ARS-BARC, D.J.Bolt; USDA-ARS-MARC, D. D. Lunstra, J.J. Ford, R.K. Christenson;b. Ovulation control, endocrine regulation of the estrous cycle: University ofIllinois, P.J. Dziuk; Purdue University, M.A. Diekman; Iowa State University, L.L.Anderson, A.J. Conley, S.P. Ford, L.K. Christenson; Kansas State University, D.L.Davis; Michigan State University, H.A. Tucker, W.R. Dukelow; Univ

Wisconsin – Dr. John J. Parrish Department of Animal Sciences 1675 Observatory Drive University of Wisconsin Madison, WI 53706 Tel: 608-263-4324 Fax: 608-262-5157 Email: parrish@ansci.wisc.edu Wyoming – Dr. Steve Ford Department of Animal Science P.