Using Topics in Animal Science as a Platform to Teach Bioethics to University Honors Program Students

A seminar course was developed using topics in animal science as a platform for teaching bioethics to university honors program students. The seminar course was structured to provide students with an introduction to major ethical theories (e.g., ethical relativism, utilitarianism), followed by an overview of livestock assisted reproductive technologies such as artificial insemination, embryo transfer, in vitro fertilization, and nuclear transfer (“cloning”). The latter half of the course focused on student-developed presentations on a bioethical issue. Students from a wide variety of majors from several different colleges within Iowa State University successfully completed the course. This course serves as an excellent example of engaging students in meaningful dialogue on contemporary societal issues while concurrently developing critical thinking skills of students and teaching them about bioethics

Cryopreservation of Preimplantation Embryos of Cattle, Sheep, and Goats

Preimplantation embryos from cattle, sheep, and goats may be cryopreserved for short- or long-term storage. Preimplantation embryos consist predominantly of water, and the avoidance of intracellular ice crystal formation during the cryopreservation process is of paramount importance to maintain embryo viability. Embryos are placed into a hypertonic solution (1.4 – 1.5 M) of a cryoprotective agent (CPA) such as ethylene glycol (EG) or glycerol (GLYC) to create an osmotic gradient that facilitates cellular dehydration. After embryos reach osmotic equilibrium in the CPA solution, they are individually loaded in the hypertonic CPA solution into 0.25 ml plastic straws for freezing. Embryos are placed into a controlled rate freezer at a temperature of -6°C. Ice crystal formation is induced in the CPA solution surrounding the embryo, and crystallization causes an increase in the concentration of CPA outside of the embryo, causing further cellular dehydration. Embryos are cooled at a rate of 0.5°C/min, enabling further dehydration, to a temperature of -34°C before being plunged into liquid nitrogen (-196°C). Cryopreserved embryos must be thawed prior to transfer to a recipient (surrogate) female. Straws containing the embryos are removed from the liquid nitrogen dewar, held in room temperature air for 3 to 5 sec, and placed into a 37°C water bath for 25 to 30 sec. Embryos cryopreserved in GLYC are placed into a 1 M solution of sucrose for 10 min for removal of the CPA before transfer to a recipient (surrogate) female. Embryos cryopreserved in EG, however, may be directly transferred to the uterus of a recipient

International Engagement to Enhance Global Food Security: An Example in the Republic of Kosova

Since 2011, personnel at Iowa State University (ISU) have been engaged with the southeastern European country of the Republic of Kosova (more commonly known as Kosovo). The purpose of this engagement has been to empower Kosovars to transform their agricultural sector so that this newly independent country can reduce its reliance on food imports and develop into a food secure nation. Activities conducted under terms of the international memorandum of cooperation and understanding between ISU and the University of Prishtina (UP) are described in this report. Accomplishments resulting from this partnership include: 1) guest lectures by ISU faculty to UP veterinary students, 2) teaching of workshops and courses by ISU faculty to a global population of students enrolled in UP’s International Summer University 2-week educational program, 3) on-farm consultations with Kosovo dairy farmers, 4) establishment of relationships with livestock-oriented associations in Kosovo, and 5) birth of the first-ever bovine embryo transfer calf in Kosovo. These and other on-going activities are heightening awareness of the need to improve agricultural productivity in Kosovo, particularly in the dairy sector, to stop the flow of euros out of the country for purchase of food that could and should be produced within Kosovo

Impact of Embryo Transfer Technology on the Production of Artificial Insemination Sires for the U.S. Dairy Cattle Industry

Embryo transfer has played an important role in genetic improvement of dairy cattle over the past several decades. Embryo transfer (ET) has impacted the dairy cattle industry not only through the production of cows via ET, but also through the production of bulls who have subsequently been utilized in the artificial insemination (AI) industry. In this study we attempted to quantify the magnitude of impact that ET has made in the production of AI sires used in the U.S. dairy cattle industry. By analyzing publicly available data from five major bovine AI companies we discovered that 99% of currently available Holstein AI sires and 95% of currently available Jersey AI sires were produced via ET or had parents or grandparents produced via ET. These data clearly demonstrate the impact that ET has played in dairy cattle genetic improvement through the production of AI sires. To the best of our knowledge these data are the first to quantify the impact of ET technology on production of AI sires used in U.S. dairy cattle industry

Use of Direct Thaw Insemination to Establish Pregnancies with Frozen–Thawed Semen from a Standard Jack

Pregnancy rates reported after artificial insemination with frozen–thawed jack spermatozoa have been relatively low compared with those attained in other species. Cholesterol is known to influence post-thaw fertility of both jack and stallion semen, and altering the amount of cholesterol in the freezing extender may help improve the fertility of frozen–thawed jack semen samples. In this study, we report clinical work that was performed using semen samples collected from a single jack. Samples were extended in EZ Mixin OF and then slowly cooled to 5°C. Extended semen samples were centrifuged at 400 × g for 10 minutes and the supernatant was discarded. Spermatozoa were resuspended in freezing medium to a final concentration of 400 × 106 cells/mL and were later frozen in liquid nitrogen vapor. Freezing extender treatments containing 2% ethylene glycol included the following: (1) 20% egg yolk (EY), (2) 5% EY, and (3) 20% EY + 60 mM hydroxypropyl-β-cyclodextrin (β-CD). For this study, a total of 28 mares aged 2 to 18 years was used over five breeding seasons (82 total cycles). Mares were administered human chorionic gonadotropin to induce ovulation when the dominant follicle was ≥35 mm in diameter. They were inseminated within 6 hours before ovulation and again within 6 hours after ovulation. Pregnancy rates obtained were as follows: (1) 6.25% (one of 15 matings) for 20% EY, (2) 46.5% (20 of 43 matings) for 5% EY, and (3) 58.5% (14 of 24 matings) for 20% EY + 60 mM β-CD. These data suggest that binding of cholesterol with β-CD enhances post-thaw fertility of jack semen samples. We conclude that acceptable pregnancy rates could be achieved with frozen–thawed jack semen samples cryopreserved in 5% EY or 20% EY + 60 mM β-CD using direct post-thaw insemination

The Effect of 2-Hydroxypropyl-β-Cyclodextrin on Post-Thaw Parameters of Cryopreserved Jack and Stallion Semen

Cyclodextrins improve post-thaw viability and motility of semen as well as mediate cholesterol efflux and subsequent acrosome reaction in spermatozoa from several species. The objectives of this study were: (a) to assess the effect of prefreeze addition of 60 mM hydroxypropyl-β-cyclodextrin (β-CD) on post-thaw viability and motility of jack and stallion semen cryopreserved in ethylene glycol-based freezing extenders containing 5% or 20% (v/v) egg yolk (LEY and HEY, respectively), and (b) to evaluate the ability of 1 μM calcium ionophore A23187 and/or 60 mM β-CD to induce acrosome reaction in thawed jack and stallion spermatozoa. Post-thaw motility of spermatozoa cryopreserved in HEY was higher (P \u3c .05) for jack but lower (P \u3c .05) for stallion spermatozoa when compared with LEY. Jack and stallion spermatozoa both exhibited higher (P \u3c .05) motility when cryopreserved in 60 mM β-CD than without β-CD. Curvilinear velocity was faster (P \u3c .05) for jack and stallion spermatozoa cryopreserved in LEY than in HEY. A treatment × time interaction affected (P \u3c .05) the proportion of spermatozoa that underwent acrosome reaction. Post-thaw incubation of jack and stallion spermatozoa with β-CD for 90 minutes induced acrosome reaction in 85% and 22% of viable sperm cells, respectively; however, only 32% of jack and 8% of stallion spermatozoa incubated with calcium ionophore underwent acrosome reaction. This study is the first to evaluate the effect of β-CD (not loaded with cholesterol) on jack semen cryopreservation, and results reveal that β-CD may be a useful tool to enhance semen cryopreservation and to induce post-thaw acrosome reaction in jack spermatozoa

Effect of Parenteral Vitamin E and/or A on Reproductive Performance of Ewes Mated on Pasture or in Drylot

Forty-four Hampshire (H) and 41 Suffolk (S) ewes were allotted within breed to one of four treatment groups (VitA, VitE, VitAE, and Control) to evaluate the effect of supplemental vitamin E and A on reproductive performance of ewes mated on pasture or in drylot. Beginning two weeks before the mating period, ewes received 0 or 300 IU of vitamin E every 14 days and 0 or 250,000 IU of vitamin A every 28 days. Hampshire ewes remained on pasture during the mating period, whereas S ewes were moved to drylot. Treatment did not affect ovulation rate (OR), embryonic loss (EL), fetal loss (FL) or litter size (LS) of H ewes. Embryonic loss was higher (P\u3c.05) in the H yearlings and two-year olds than in older ewes. Litter size was lower (P\u3c.01) for H yearlings compared with other age groups. Suffolk ewes in the VitE group exhibited a lower (P\u3c.01) OR than S ewes in other treatment groups, but no effect of treatment was observed for EL, FL, or LS. Although S yearling ewes did not differ from ewes of other age groups for OR and EL, they did produce fewer (P\u3c.05) lambs. Analysis of serum samples revealed that H yearling ewes exhibited lower (P\u3c.05) serum a-tocopherol levels than older H ewes. In addition, H ewes had a higher (P\u3c.05) serum a-tocopherol level than S ewes at the beginning of study when they were managed as one group. Even though age and breed influenced certain reproductive parameters, results of this study indicate little effect of supplemental vitamin E and A on the overall reproductive efficiency of ewes mated on pasture or in drylot

The Influence of MGA and PG600 on the Out of Season Reproductive Performance of Ewes

Seasonal lamb supply has been established as one of the major hindrances to the American sheep industry. The ability to consistently lamb ewes on an accelerated production system offers additional benefits of reduced maintenance costs, more uniform cash flow along with reduced labor and facility demands. Previous work at McNay with spring breeding indicated that light priming rams regardless of genetic base improved conception rates, however, MGA feeding postweaning gave inconsistent and sometimes depressed reproductive activity in ewes. This study was conducted to evaluate the use of MGA in late lactation and a single PG600 injection at weaning, either individually or in combination

A comparison of the number of inner cell mass and trophectoderm cells of preimplantation Meishan and Yorkshire pig embryos at similar developmental stages

Day 12 blastocysts from Meishan gilts contain fewer cells than do day 12 blastocysts from Yorkshire gilts. The purpose of this study was to evaluate the effect of breed on the relative numbers of inner cell mass and trophectoderm cells in Meishan and Yorkshire embryos at similar stages. Embryos were collected on days 5.5–6.5 of gestation and were subjected to image analysis and differential cell staining. No breed differences were detected in the thickness of zona pellucida or in the areas of the perivitelline space, embryo proper, blastocoel and inner cell mass at any of the developmental stages examined (compact morula, early blastocyst or blastocyst). However, differences were observed in the pattern of growth of embryos from Meishan versus Yorkshire gilts. The total number of cells of Meishan embryos from Meishan gilts increased progressively from the compact morula through the blastocyst stage, whereas the total number of cells of embryos from Yorkshire gilts remained constant from compact morula through to early blastocyst, and then increased markedly from the early blastocyst to the blastocyst stage. At the blastocyst stage, Meishan embryos contained fewer (P \u3c 0.05) cells than did Yorkshire embryos, and this lower number of cells was due entirely to fewer (P\u3c 0.05) trophectoderm cells. As the number of inner cell mass cells increased during embryonic growth, Meishan embryos exhibited a slower (P \u3c 0.02) increase in the number of trophectoderm cells than did Yorkshire embryos. These results demonstrate that the reduced number of cells present in Meishan embryos results from a selective reduction in the number of trophectoderm, but not inner cell mass, cells

A Preliminary Report on the Frequency of Scrapie Susceptibility Alleles in Hampshire Sheep

Blood samples were collected from a total of 201 animals in five purebred Hampshire sheep flocks. DNA was isolated from the samples, and the protein-coding region of the prion protein gene was amplified using the polymerase chain reaction. The allelic frequencies of the prion protein codons 171 and 136 were determined. Results revealed that the codon 171 alleles Q, R, and H were present at frequencies of 72%, 27% and 1%, respectively. A subset of samples (n=48) was randomly selected for codon 136 genotyping. The codon 136 V allele, an allele not frequently observed in Suffolk sheep, was present in animals from three of five flocks at a frequency ranging from 7 to 33% of the animals tested within each flock. These data comprise the first report on the prevalence of scrapie susceptibility alleles in Hampshire sheep