Professor of Animal Science ME Ensminger Endowed Chair of International Animal Agriculture Associate Director in charge of Livestock and Animal Health Programs, Center for Sustainable Rural Livelihoods
This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
Brucella ovis (B. ovis) is the predominant cause of ram epididymitis, a disease known to contrib... more Brucella ovis (B. ovis) is the predominant cause of ram epididymitis, a disease known to contribute to poor reproductive performance in sheep flocks throughout the world. Three hundred seventy-one serum samples from 45 multiple-sire sheep flocks located in 23 Iowa counties were submitted to the Western Slope Animal Diagnostic Laboratory in Grand Junction, Colorado for B. ovis ELISA testing. None of the tested rams were seropositive for B. ovis. This study has important implications in the nationwide control and eradication of ram epididymitis caused by B. ovis.
The objectives of this research were to determine the effects of beta-mercaptoethanol (B-ME) and ... more The objectives of this research were to determine the effects of beta-mercaptoethanol (B-ME) and fetal bovine serum (FBS) on in vitro development of bovine embryos derived from oocytes matured and fertilized in vitro and to examine the mechanism through which B-ME may influence embryo development. A 2 x 2 factorial treatment arrangement was used to evaluate the effect of 0 or 100 uM B-ME and 0 % or 10 % FBS on embryos cultured in Medium 199 (M199) in the absence of somatic cells. Embryos were randomly allocated within stage of development (<8 cells or 8-16 cells) to one of four treatment combinations and were cultured for 6 days. Both B-ME and FBS promoted increased (p<0.01) development of embryos to the blastocyst stage, and their effects were greater (p<0.01) in 8- to 16-cell embryos than in embryos having fewer than 8 cells at the initi-ation of treatment. The cysteine and cystine content of M199, with and without B-ME, were determined by HPLC. Medium supplemented w...
Journal of reproduction and fertility. Supplement, 1993
Prenatal mortality in European pigs is estimated at 30-40%, the majority of which occurs between ... more Prenatal mortality in European pigs is estimated at 30-40%, the majority of which occurs between days 12 and 18 after mating. Chinese Meishan pigs are prolific, averaging three to five more pigs per litter than do European breeds. Early reports into the fecundity of Meishan females suggested that their prolificacy resulted from lower embryonic mortality when compared with European females exhibiting the same ovulation rate. The preponderance of evidence suggests that there are no differences between Meishan and European breeds in either morphological embryo diversity within a litter or embryo mortality before day 12 after mating. Recent studies from our laboratory suggest that preimplantation embryos from Meishan females exhibit markedly reduced growth rates and oestrogen secretory activities through day 12 when compared with embryos from Yorkshire females. The significantly reduced conceptus sizes of Meishan versus European breeds on day 30 of gestation provide additional evidence ...
One of the factors limiting successful processing of alpaca (Vicugna pacos) semen is the viscosit... more One of the factors limiting successful processing of alpaca (Vicugna pacos) semen is the viscosity of seminal plasma. The viscous nature of the collected ejaculate has hindered sperm cryopreservation as well as artificial insemination (AI) under field conditions. The objective of this investigation was to evaluate recovery, motility, and plasma membrane integrity of alpaca spermatozoa after centrifugation in one of two different solutions at one of three different combinations of speed and time. A total of 24 ejaculates was recovered from seven reproductively sound Huacaya males using a modified artificial vagina (AV) after training the animals for semen collection. A 2 × 3 factorial treatment arrangement was utilized for this study. Ejaculates were divided into fractions for centrifugation in one of two solutions (Tris extender or PureSperm®80 density gradient solution) at one of three combinations of speed and time (492 × g for 15 min, 1968 × g for 10 min, or 4448 × g for 7 min). The experiment was replicated eight times. Results: Analysis revealed that centrifugation at 4448 × g for 7 min in PureSperm®80 provided a high recovery rate of spermatozoa with the highest sperm motility and functional integrity of plasma membrane post-centrifugation. Results suggest that adoption of this procedure (centrifugation at 4448 × g for 7 min in PureSperm®80) in the initial processing of alpaca ejaculates may enhance subsequent ability to use semen for AI and other assisted reproductive biotechnologies in this species
Great teachers have the extraordinary ability to inspire and motivate even those students who res... more Great teachers have the extraordinary ability to inspire and motivate even those students who resist learning. The top educators are not only knowledgeable about the content of the course they are teaching but also of the information, literature and practice of instructional delivery to their audience. Many exemplary educators have been profiled and studied; however, there is a paucity of information pertaining to how the top animal science teachers teach. The objective of this study was to identify and describe characteristics of award-winning animal science teachers. The inclusion criterion for selecting faculty was being bestowed an excellence in teaching award through their professional organization. Each teacher answered a series of questions about themselves, their students, and the class being taught. Lecture was captured using a digital all-inclusive camera and later analyzed for pedagogical trends and instructor-student interactions. Despite a variety of topics being taught...
Future Aspects in Human In Vitro Fertilization, 1987
Micromanipulation of bovine embryos to produce monozygotic twins is now being offered by some of ... more Micromanipulation of bovine embryos to produce monozygotic twins is now being offered by some of the more progressive commercial cattle embryo transplant units around the world. One of the primary advantages of embryo splitting is the capability of increasing the number of progeny from genetically superior females. Pregnancy rates can be obtained in cattle from fresh “half embryos (demi-embryos) which are comparable to those of intact embryos (Voelkel et al. 1984; Takeda et al. 1986). When sufficient surrogate females are available, good quality embryos can be bisected and transferred, thus potentially doubling the number of offspring from embryos harvested from valuable donor animals.
The aim was to improve the pregnancy rate in recipient alpacas following embryo transfer. Two exp... more The aim was to improve the pregnancy rate in recipient alpacas following embryo transfer. Two experiments were carried out, Experiment 1 in the southern highlands (4,100 m elevation) and Experiment 2 (E2) in the central highlands (3,200 m elevation) of the Peruvian Andes. In both experiments, a group of alpaca donors was subjected to superovulation and embryo flushing as per procedures already described (Vivanco 2013 29th Annu. Mtg. European Embryo Transfer Association, 43–74). The synchronization of the recipient alpacas and ovulation induction in both experiments was made by ultrasonography selection of the alpacas with follicles greater than 8 mm and their exposure to vasectomized males followed by an injection of GnRH (0.0042 mg of acetate of buserelin, Buserelina Zoovet®, Laboratorio Zoovet, Santa Fe, Argentina). The embryo transfers in both locations were made by laparoscopically aided laparotomy 6.5 days after ovulation induction. In Experiment 1, 29 recipient alpacas were di...
The objective of this applied field study was to assess the feasibility of successfully performin... more The objective of this applied field study was to assess the feasibility of successfully performing bovine embryo transfer in the Republic of Kosova—a feat that had not yet been accomplished in this newly independent (2008) eastern European country. Three Holstein heifers at the Iowa State University dairy farm were superovulated with a conventional descending dose regimen of FSH (Folltropin). Approximately 12 and 24 h after the observed onset of oestrus, heifers were inseminated with semen from a single Red Holstein bull. Embryos were non-surgically collected and washed in accordance with IETS procedures for sanitary handling of embryos. Embryos were cryopreserved for subsequent direct transfer. After obtaining an import permit from the Kosovo Food and Veterinary Agency, embryos were approved for export to the Republic of Kosova by the US Department of Agriculture, Animal Plant Health Inspection Service. Embryos were shipped via an express courier service. A total of 19 embryos were...
SUMMARYSheep are a valuable livestock species because of their ability to convert forages, as wel... more SUMMARYSheep are a valuable livestock species because of their ability to convert forages, as well as feedstuffs not suitable for human consumption, into meat and milk that are important sources of human dietary protein. Sheep are the most abundant ruminant livestock species in Egypt, and great opportunity exists to enhance their productivity though implementation of a genetic improvement program utilizing the advanced reproductive technologies of artificial insemination and embryo transfer. These two reproductive technologies permit the production of more offspring from genetically superior animals in a shorter amount of time than would be possible through conventional breeding. It will be important to match the appropriate breeds of sheep with the proper nutritional and production environments that will enable animals to express their full genetic potential for enhanced production of meat, milk and fiber.
M.L. Pugh, animal science graduate research assistant Mel Pence, adjunct instructor of veterinary... more M.L. Pugh, animal science graduate research assistant Mel Pence, adjunct instructor of veterinary medicine J.N. Caamano, animal science graduate research assistant Suelee Robbe, adjunct instructor of veterinary medicine L.L. Timms, associate professor of animal science John U. Thomson, professor of veterinary medicine Russ Bredahl, field livestock extension specialist C.R. Youngs, associate professor of animal science
Reproductive performance is paramount to the success of livestock production enterprises focused ... more Reproductive performance is paramount to the success of livestock production enterprises focused on lamb meat production. Reproductive success is influenced by various factors, possibly including the reproductive tract microbial communities present at the time of copulation and throughout pregnancy. There are few publications that identify the vaginal microbial communities of livestock, and even fewer exist for sheep. To compare ewe vaginal microbial communities, vaginal swabs were taken from 67 Hampshire and Hampshire X Suffolk crossbred ewes from the Iowa State University sheep farm at a pre-breeding time point (S1) and after pregnancy testing (S2). Animals that were determined pregnant were sampled again within a few days of expected parturition (S3). DNA was extracted from these swabs, and 16S rRNA gene Illumina MiSeq amplicon sequencing was conducted to fingerprint the bacterial communities found within this system. Pre-breeding time point samples showed no differences in commu...
Reproductive biotechnologies have contributed to many major advances in livestock production, and... more Reproductive biotechnologies have contributed to many major advances in livestock production, and the proper application of these technologies can lead to livestock with superior genetic traits. This is vitally important given the high rates of malnourishment and poverty in developing countries, where communities could greatly benefit from an increase in meat and dairy products. Collaborating with scientists across the world, Dr Curtis R. Youngs of Iowa State University aims to increase the production of animal-derived foods in developing nations by applying reproductive biotechnologies to improve the efficiency and sustainability of livestock production.
The alpaca (Vicugna pacos) is an important species for the production of fiber and food. Genetic ... more The alpaca (Vicugna pacos) is an important species for the production of fiber and food. Genetic improvement programs for alpacas have been hindered, however, by the lack of field-practical techniques for artificial insemination and embryo transfer. In particular, successful techniques for the cryopreservation of alpaca preimplantation embryos have not been reported previously. The objective of this study was to develop a field-practical and efficacious technique for cryopreservation of alpaca preimplantation embryos using a modification of a vitrification protocol originally devised for horses and adapted for dromedary camels. Four naturally cycling non-superovulated Huacaya females serving as embryo donors were mated to males of proven fertility. Donors received 30 μg of gonadorelin at the time of breeding, and embryos were non-surgically recovered 7 days after mating. Recovered embryos (n = 4) were placed individually through a series of three vitrification solutions at 20°C (VS1...
This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
Brucella ovis (B. ovis) is the predominant cause of ram epididymitis, a disease known to contrib... more Brucella ovis (B. ovis) is the predominant cause of ram epididymitis, a disease known to contribute to poor reproductive performance in sheep flocks throughout the world. Three hundred seventy-one serum samples from 45 multiple-sire sheep flocks located in 23 Iowa counties were submitted to the Western Slope Animal Diagnostic Laboratory in Grand Junction, Colorado for B. ovis ELISA testing. None of the tested rams were seropositive for B. ovis. This study has important implications in the nationwide control and eradication of ram epididymitis caused by B. ovis.
The objectives of this research were to determine the effects of beta-mercaptoethanol (B-ME) and ... more The objectives of this research were to determine the effects of beta-mercaptoethanol (B-ME) and fetal bovine serum (FBS) on in vitro development of bovine embryos derived from oocytes matured and fertilized in vitro and to examine the mechanism through which B-ME may influence embryo development. A 2 x 2 factorial treatment arrangement was used to evaluate the effect of 0 or 100 uM B-ME and 0 % or 10 % FBS on embryos cultured in Medium 199 (M199) in the absence of somatic cells. Embryos were randomly allocated within stage of development (<8 cells or 8-16 cells) to one of four treatment combinations and were cultured for 6 days. Both B-ME and FBS promoted increased (p<0.01) development of embryos to the blastocyst stage, and their effects were greater (p<0.01) in 8- to 16-cell embryos than in embryos having fewer than 8 cells at the initi-ation of treatment. The cysteine and cystine content of M199, with and without B-ME, were determined by HPLC. Medium supplemented w...
Journal of reproduction and fertility. Supplement, 1993
Prenatal mortality in European pigs is estimated at 30-40%, the majority of which occurs between ... more Prenatal mortality in European pigs is estimated at 30-40%, the majority of which occurs between days 12 and 18 after mating. Chinese Meishan pigs are prolific, averaging three to five more pigs per litter than do European breeds. Early reports into the fecundity of Meishan females suggested that their prolificacy resulted from lower embryonic mortality when compared with European females exhibiting the same ovulation rate. The preponderance of evidence suggests that there are no differences between Meishan and European breeds in either morphological embryo diversity within a litter or embryo mortality before day 12 after mating. Recent studies from our laboratory suggest that preimplantation embryos from Meishan females exhibit markedly reduced growth rates and oestrogen secretory activities through day 12 when compared with embryos from Yorkshire females. The significantly reduced conceptus sizes of Meishan versus European breeds on day 30 of gestation provide additional evidence ...
One of the factors limiting successful processing of alpaca (Vicugna pacos) semen is the viscosit... more One of the factors limiting successful processing of alpaca (Vicugna pacos) semen is the viscosity of seminal plasma. The viscous nature of the collected ejaculate has hindered sperm cryopreservation as well as artificial insemination (AI) under field conditions. The objective of this investigation was to evaluate recovery, motility, and plasma membrane integrity of alpaca spermatozoa after centrifugation in one of two different solutions at one of three different combinations of speed and time. A total of 24 ejaculates was recovered from seven reproductively sound Huacaya males using a modified artificial vagina (AV) after training the animals for semen collection. A 2 × 3 factorial treatment arrangement was utilized for this study. Ejaculates were divided into fractions for centrifugation in one of two solutions (Tris extender or PureSperm®80 density gradient solution) at one of three combinations of speed and time (492 × g for 15 min, 1968 × g for 10 min, or 4448 × g for 7 min). The experiment was replicated eight times. Results: Analysis revealed that centrifugation at 4448 × g for 7 min in PureSperm®80 provided a high recovery rate of spermatozoa with the highest sperm motility and functional integrity of plasma membrane post-centrifugation. Results suggest that adoption of this procedure (centrifugation at 4448 × g for 7 min in PureSperm®80) in the initial processing of alpaca ejaculates may enhance subsequent ability to use semen for AI and other assisted reproductive biotechnologies in this species
Great teachers have the extraordinary ability to inspire and motivate even those students who res... more Great teachers have the extraordinary ability to inspire and motivate even those students who resist learning. The top educators are not only knowledgeable about the content of the course they are teaching but also of the information, literature and practice of instructional delivery to their audience. Many exemplary educators have been profiled and studied; however, there is a paucity of information pertaining to how the top animal science teachers teach. The objective of this study was to identify and describe characteristics of award-winning animal science teachers. The inclusion criterion for selecting faculty was being bestowed an excellence in teaching award through their professional organization. Each teacher answered a series of questions about themselves, their students, and the class being taught. Lecture was captured using a digital all-inclusive camera and later analyzed for pedagogical trends and instructor-student interactions. Despite a variety of topics being taught...
Future Aspects in Human In Vitro Fertilization, 1987
Micromanipulation of bovine embryos to produce monozygotic twins is now being offered by some of ... more Micromanipulation of bovine embryos to produce monozygotic twins is now being offered by some of the more progressive commercial cattle embryo transplant units around the world. One of the primary advantages of embryo splitting is the capability of increasing the number of progeny from genetically superior females. Pregnancy rates can be obtained in cattle from fresh “half embryos (demi-embryos) which are comparable to those of intact embryos (Voelkel et al. 1984; Takeda et al. 1986). When sufficient surrogate females are available, good quality embryos can be bisected and transferred, thus potentially doubling the number of offspring from embryos harvested from valuable donor animals.
The aim was to improve the pregnancy rate in recipient alpacas following embryo transfer. Two exp... more The aim was to improve the pregnancy rate in recipient alpacas following embryo transfer. Two experiments were carried out, Experiment 1 in the southern highlands (4,100 m elevation) and Experiment 2 (E2) in the central highlands (3,200 m elevation) of the Peruvian Andes. In both experiments, a group of alpaca donors was subjected to superovulation and embryo flushing as per procedures already described (Vivanco 2013 29th Annu. Mtg. European Embryo Transfer Association, 43–74). The synchronization of the recipient alpacas and ovulation induction in both experiments was made by ultrasonography selection of the alpacas with follicles greater than 8 mm and their exposure to vasectomized males followed by an injection of GnRH (0.0042 mg of acetate of buserelin, Buserelina Zoovet®, Laboratorio Zoovet, Santa Fe, Argentina). The embryo transfers in both locations were made by laparoscopically aided laparotomy 6.5 days after ovulation induction. In Experiment 1, 29 recipient alpacas were di...
The objective of this applied field study was to assess the feasibility of successfully performin... more The objective of this applied field study was to assess the feasibility of successfully performing bovine embryo transfer in the Republic of Kosova—a feat that had not yet been accomplished in this newly independent (2008) eastern European country. Three Holstein heifers at the Iowa State University dairy farm were superovulated with a conventional descending dose regimen of FSH (Folltropin). Approximately 12 and 24 h after the observed onset of oestrus, heifers were inseminated with semen from a single Red Holstein bull. Embryos were non-surgically collected and washed in accordance with IETS procedures for sanitary handling of embryos. Embryos were cryopreserved for subsequent direct transfer. After obtaining an import permit from the Kosovo Food and Veterinary Agency, embryos were approved for export to the Republic of Kosova by the US Department of Agriculture, Animal Plant Health Inspection Service. Embryos were shipped via an express courier service. A total of 19 embryos were...
SUMMARYSheep are a valuable livestock species because of their ability to convert forages, as wel... more SUMMARYSheep are a valuable livestock species because of their ability to convert forages, as well as feedstuffs not suitable for human consumption, into meat and milk that are important sources of human dietary protein. Sheep are the most abundant ruminant livestock species in Egypt, and great opportunity exists to enhance their productivity though implementation of a genetic improvement program utilizing the advanced reproductive technologies of artificial insemination and embryo transfer. These two reproductive technologies permit the production of more offspring from genetically superior animals in a shorter amount of time than would be possible through conventional breeding. It will be important to match the appropriate breeds of sheep with the proper nutritional and production environments that will enable animals to express their full genetic potential for enhanced production of meat, milk and fiber.
M.L. Pugh, animal science graduate research assistant Mel Pence, adjunct instructor of veterinary... more M.L. Pugh, animal science graduate research assistant Mel Pence, adjunct instructor of veterinary medicine J.N. Caamano, animal science graduate research assistant Suelee Robbe, adjunct instructor of veterinary medicine L.L. Timms, associate professor of animal science John U. Thomson, professor of veterinary medicine Russ Bredahl, field livestock extension specialist C.R. Youngs, associate professor of animal science
Reproductive performance is paramount to the success of livestock production enterprises focused ... more Reproductive performance is paramount to the success of livestock production enterprises focused on lamb meat production. Reproductive success is influenced by various factors, possibly including the reproductive tract microbial communities present at the time of copulation and throughout pregnancy. There are few publications that identify the vaginal microbial communities of livestock, and even fewer exist for sheep. To compare ewe vaginal microbial communities, vaginal swabs were taken from 67 Hampshire and Hampshire X Suffolk crossbred ewes from the Iowa State University sheep farm at a pre-breeding time point (S1) and after pregnancy testing (S2). Animals that were determined pregnant were sampled again within a few days of expected parturition (S3). DNA was extracted from these swabs, and 16S rRNA gene Illumina MiSeq amplicon sequencing was conducted to fingerprint the bacterial communities found within this system. Pre-breeding time point samples showed no differences in commu...
Reproductive biotechnologies have contributed to many major advances in livestock production, and... more Reproductive biotechnologies have contributed to many major advances in livestock production, and the proper application of these technologies can lead to livestock with superior genetic traits. This is vitally important given the high rates of malnourishment and poverty in developing countries, where communities could greatly benefit from an increase in meat and dairy products. Collaborating with scientists across the world, Dr Curtis R. Youngs of Iowa State University aims to increase the production of animal-derived foods in developing nations by applying reproductive biotechnologies to improve the efficiency and sustainability of livestock production.
The alpaca (Vicugna pacos) is an important species for the production of fiber and food. Genetic ... more The alpaca (Vicugna pacos) is an important species for the production of fiber and food. Genetic improvement programs for alpacas have been hindered, however, by the lack of field-practical techniques for artificial insemination and embryo transfer. In particular, successful techniques for the cryopreservation of alpaca preimplantation embryos have not been reported previously. The objective of this study was to develop a field-practical and efficacious technique for cryopreservation of alpaca preimplantation embryos using a modification of a vitrification protocol originally devised for horses and adapted for dromedary camels. Four naturally cycling non-superovulated Huacaya females serving as embryo donors were mated to males of proven fertility. Donors received 30 μg of gonadorelin at the time of breeding, and embryos were non-surgically recovered 7 days after mating. Recovered embryos (n = 4) were placed individually through a series of three vitrification solutions at 20°C (VS1...
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