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The objective was to evaluate the effects of peripartum supplementation of a methionine hydroxy analogue (MHA) to primiparous, spring-calving beef females on dam and progeny performance. Angus heifers (n = 60) were blocked by expected parturition date, stratified by body weight (BW) and body condition score (BCS), and randomized to 1 of 15 pens. Pens were randomly assigned to 1 of 3 dietary treatments: a basal diet supplemented with 0 (M0), 15 (M15), or 30 (M30) g/animal/d of MHA (provided as MFP feed supplement, Novus International Inc., St. Charles, MO). Diets were fed from 45 ± 13 (SD) d pre-calving through 81 ± 13 d postpartum (DPP), after which all cow–calf pairs were managed as a single group on pasture until weaning (199 ± 13 DPP). Dam BW, BCS, and blood samples were taken at 6 predetermined timepoints. Progeny data were collected at birth, 2 intermediate timepoints, and at weaning. Milk samples were collected for composition analysis at 7 ± 2 DPP and at 55 ± 5 DPP. Serial progesterone samples were analyzed to establish resumption of cyclicity, and ultrasonography was performed at 55 ± 5 DPP to evaluate ovarian function. Cows were bred via artificial insemination at 82 ± 13 DPP and subsequently exposed to bulls for a 55-d breeding season. Pen was the experimental unit, and preplanned orthogonal contrasts were tested (linear effect and M0 vs. M15 + M30). Dam BW and BCS were not affected by treatment (P ≥ 0.29) throughout the study. Week 1 milk fat concentration increased linearly (P = 0.05) and total solids tended to increase linearly (P = 0.07) as MHA increased; however, no other milk components were affected (P ≥ 0.16). Treatment did not affect (P ≥ 0.16) dam reproductive parameters or progeny growth from birth until weaning. Post-calving, circulating methionine equivalents tended to linearly increase (P = 0.10) with increasing MHA supplementation. At breeding, plasma urea N linearly decreased (P = 0.03) with increased supplementation of MHA, and plasma non-esterified fatty acids were less (P = 0.04) in MHA-supplemented dams compared with dams receiving no MHA. Maternal circulating glucose, glutathione peroxidase, and thiobarbituric acid-reactive substances were not affected (P ≥ 0.15) by treatment at any point. These data indicate that peripartum supplementation of MHA may increase milk fat composition shortly after calving, but MHA supplementation did not improve progeny growth or dam reproductive performance in the current study.

Global food security – Part 4; Enhancing a struggling food system World Bank has characterized the livestock sector as a "pillar of the global food system and a contributor to poverty reduction, food security and agricultural development." (3) At the same time, World Bank also points out that improvements are needed in the livestock sector. In addition to increasing production efficiency, one area needing improvement is the reduction of the environmental impact of the livestock industry. Professor Curtis R Youngs, the M.E. Ensminger Endowed Chair of International Animal Agriculture at Iowa State University, analyses the flaws of the food system in his fourth part analysis of global food security.

Global food security – Part 3 Curtis R Youngs, Professor & M.E. Ensminger Endowed Chair of International Animal Agriculture, discusses in his third part the challenges of global food security, encountering issues with poverty linked to malnutrition and the world events – such as SARS-CoV-2 global health pandemic, Russian invasion of Ukraine, and rampant inflation – causing food security issues. Analysing themes of privilege, Professor Youngs looks at child malnourishment and dietary requirements for those with minimal access to food, and the struggle many families have in choosing between food and livelihood. He also discusses the carbon impact of our current livestock and agricultural systems, and how we can change them to better the environment and feed more people.

International audience; Surra, caused by Trypanosoma evansi, is a re-emerging animal trypanosomosis, which is of special concern for camel-rearing regions of Africa and Asia. Surra decreases milk yield, lessens animal body condition score and reduces market value of exported animals resulting in substantial economic losses. A cross-sectional seroprevalence study of dromedary camels was conducted in Algeria, and major risk factors associated with infection were identified by collecting data on animal characteristics and herd management practices. The seroprevalence of T. evansi infection was determined in sera of 865 camels from 82 herds located in eastern Algeria using an antibody test (card agglutination test for Trypanosomiasis - CATT/T. evansi). Individual and herd seroprevalence were 49.5% and 73.2%, respectively, indicating substantial exposure of camels to T. evansi in the four districts studied. Five significant risk factors for T. evansi hemoparasite infection were identified: geographical area, herd size, husbandry system, accessibility to natural water sources and type of watering. There was no association between breed, sex or age with T. evansi infection. Results of this study provide baseline information that will be useful for launching control programmes in the region and potentially elsewhere.

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: 1.4 M glycerol; VS2: 1.4 M glycerol + 3.6 M ethylene glycol; VS3: 3.4 M glycerol + 4.6 M ethylene glycol) before loading into an open-pulled straw (OPS) and plunging directly into liquid nitrogen for storage. At warming, each individual embryo was sequentially placed through warming solutions (WS1: 0.5 M galactose at 37°C; WS2: 0.25 M galactose at 20°C), and warmed embryos were incubated at 37°C in 5% CO2 in humidified air for 20–22 h in 1 ml Syngro® holding medium supplemented with 10% (v/v) alpaca serum to perform an initial in vitro assessment of post-warming viability. Embryos whose diameter increased during culture (n = 2) were transferred individually into synchronous recipients, whereas embryos that did not grow (n = 2) were transferred together into a single recipient to perform an in vivo assessment of post-warming viability. Initial pregnancy detection was performed ultrasonographically 29 days post-transfer when fetal heartbeat could be detected, and one of three recipients was pregnant (25% embryo survival rate). On November 13, 2019, the one pregnant recipient delivered what is believed to be the world's first cria produced from a vitrified-warmed alpaca embryo.

Great teachers have the extraordinary ability to inspire and motivate even those students who resist learning. The top educators are knowledgeable not only 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 by award-winning teachers, there were multiple trends emerging from their classrooms. Common events included reviewing highlights of previous lectures, distributing something to students, posing questions during class, and calling on students by name. Each teacher taught differently, but they all understood their audience; they grasped the subject matter and most importantly, they valued students learning. Collectively, these findings can be utilized and applied by animal science teachers in their own environments in an attempt to foster improved student learning through excellent teaching.

BackgroundPostpartum inflammation is a natural and necessary response; however, a dysfunctional inflammatory response can be detrimental to animal productivity. The objective of this study was to determine the effects of a non-steroidal anti-inflammatory drug (meloxicam) on ewe postpartum inflammatory response, ewe plasma polyunsaturated fatty acid and oxylipid concentrations, and lamb growth.ResultsAfter lambing, 36 Hampshire and Hampshire × Suffolk ewes were sequentially assigned within type of birth to control (n = 17) or meloxicam orally administered on d 1 and 4 of lactation (MEL; 90 mg,n = 19). Milk and blood samples were collected on d 1 (prior to treatment) and d 4. Milk glucose-6-phosphate was not affected by MEL. Plasma haptoglobin (Hp) concentrations were less for MEL ewes; control ewes with greater d 1 Hp concentrations had elevated Hp on d 4, but this was not the case for MEL-treated ewes. Treatment with MEL increased plasma arachidonic acid concentration by more than 4-fold in ewes rearing singles but decreased concentrations of 9,10-dihydroxyoctadecenoic acid, prostaglandin F2α, 8-iso-prostaglandin E2, and 8,9-dihydroxyeicosatetraenoic acid. Nine oxylipids in plasma had interactions of treatment with d 1 Hp concentration, all of which revealed positive associations between d 1 Hp and d 4 oxylipid concentrations for CON, but neutral or negative relationships for MEL. MEL decreased 13-hydroxyoctadecadienoic acid:13-oxooctadecadienoic acid ratio and tended to increase 9-hydroxyoctadecadienoic acid:9-oxooctadecadienoic acid ratio (both dependent on d 1 values), indicating progressive metabolism of linoleic acid-derived oxylipids occurred by enzymatic oxidation after MEL treatment. Meloxicam reduced oxylipids generated across oxygenation pathways, potentially due to an improved redox state.ConclusionsPostpartum MEL treatment of ewes decreased plasma concentrations of Hp and several oxylipids, with the greatest impact in ewes with biomarkers reflecting a greater inflammatory state before treatment. Anti-inflammatory strategies may help resolve excessive postpartum inflammation in some dams.

Great teachers have the extraordinary ability to inspire and motivate even those that resist learning. The top educators are not only knowledgeable about the content of the course they are teaching but often conscious of the information, literature and practice of instructional delivery to their audience. Many exemplary educators have been profiled and studied, followed by attempting to emulate from ambitious peers. However, there is a gap between the examples of disciplines published and what the teachers of animal science do. The objective of this study was to identify and describe what the characteristics are of the best animal science teachers in addition to identifying and describing what the characteristics are of their classroom environments and students. 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 both before and after the lecture. Lecture was captured using a digital all-inclusive camera and later analyzed for pedagogical trends, instructor-student interactions and student engagement. Despite a variety of topics being taught, there were multiple trends emerging from these classrooms. Common events included reviewing previous lectures, distributing something physical to the students, posing questions during class and calling on students by name. Most students in every class were not distracted and asked questions. Each teacher taught differently, but they all understood their audience; they grasped the subject matter and most importantly, they valued students learning. Collectively, these findings can be adopted by other teachers and be applied and utilized in their own environment in an attempt to foster improved classrooms and student learning through excellent teaching.

Boran is an endangered breed of cattle indigenous to Ethiopia and the relatively poor understanding of its reproductive physiology has impeded efforts to maximize reproductive performance of the breed. This study characterized ovarian follicular dynamics in 9 purebred Boran and 8 Boran×Holstein (B×H) crossbred cows. Ovaries of all 17 cows were examined once per day for 61 consecutive days (encompassing three periods of estrus) using transrectal ultrasonography. The mean (±standard error of mean) inter-ovulatory interval (IOI) was similar (P>0.05) in Boran (19.4 ± 0.2 days) and B×H cows (20.1 ± 0.4 days). Two (in 79% of estrous cycles) or three (in 21% of cycles) follicular waves per IOI were observed and IOI was shorter (P0.10) in both genotypes (15.8 ± 1.5 mm in Boran and 19.4 ± 2.9 mm in B×H). Boran cows possessed a greater (P

Cattle contribute significantly to the global supply of animal-derived proteins which are an important part of a well-balanced human diet. With the human population increasing by 1 billion people every 13 years, there will be an estimated 9.6 billion people on planet Earth by the year 2050. To attain global food security the amount of available food will need to double between now and then. Enhancing reproductive efficiency is a prerequisite for boosting production of meat and milk from cattle, and, fortunately, an arsenal of modern reproductive technologies is available to assist with that effort. The objective of this manuscript is to provide an overview of reproductive biotechnologies that can bolster the efficient production of meat and milk from cattle. Protocols for synchronization of estrus and synchronization of ovulation facilitate more efficient artificial insemination using conventional or sex-sorted semen. In vivo and in vitro production of preimplantation embryos from genetically superior females enable creation of multiple offspring with high production potential. Biochemical and ultrasonographic methods for pregnancy testing identify non-pregnant females that can be re-mated or sold to prevent wastage of valuable feed resources. Somatic cell nuclear transfer is used to create copies of highly productive animals, and genome editing of zygotes provides a novel opportunity to selectively enhance the genetic makeup of cattle for the benefit of animal and human health. Wise use of these reproductive technologies will increase food production from cattle and will help alleviate world hunger.

Query (Q) fever is a globally distributed zoonotic disease caused by Coxiella burnetii, a bacterial agent for which ruminants are the most prevalent natural reservoir. Data regarding Q fever infection in camels in Algeria are limited. Therefore, a survey to detect seroprevalence of C. burnetii antibodies was conducted among healthy camel populations in a vast area in southeastern Algeria to determine distribution of the Q fever causative organism and to identify risk factors associated with infection. Between January and March 2016, blood samples were collected from 184 camels and serum samples were subsequently analysed using a commercial Enzyme-Linked Immunosorbent Assay (ELISA) kit. At the time of blood collection, a questionnaire investigating 13 potential predisposing factors associated with C. burnetii seropositivity was completed for every dromedary camel and herd. Results were analysed by a chi-square (χ2) test and multivariate logistic regression. The seroprevalence of C. burnetii at the animal level was 71.2% (95% CI: 65.2–78.3) and 85.3% (95% CI: 72.8–97.8) at the herd level. At the animal level, differences in seroprevalence were observed because of herd size, animal age, animal sex, presence of ticks and contact with other herds. A multivariable logistic regression model identified three main risk factors associated with individual seropositivity: (1) age class > 11 years (OR = 8.81, 95% CI: 2.55–30.41), (2) herd size > 50 head (OR = 4.46, 95% CI: 1.01–19.59) and (3) infestation with ticks (OR 2.2; 95% CI: 1.1–4.5). This study of seroprevalence of C. burnetii infection in camels in Algeria revealed a high seroprevalence of Q fever in camel populations in southeastern Algeria and provided strong evidence that Q fever represents an economic, public health and veterinary concern. Appropriate measures should be taken to prevent the spread of C. burnetii and to reduce the risk of Q fever in farm animals and humans in this agro-ecologically and strategically important region of North Africa.

Query (Q) fever is a globally distributed zoonotic disease caused by Coxiella burnetii, a bacterial agent for which ruminants are the most prevalent natural reservoir. Data regarding Q fever infection in camels in Algeria are limited. Therefore, a survey to detect seroprevalence of C. burnetii antibodies was conducted among healthy camel populations in a vast area in southeastern Algeria to determine distribution of the Q fever causative organism and to identify risk factors associated with infection. Between January and March 2016, blood samples were collected from 184 camels and serum samples were subsequently analysed using a commercial Enzyme-Linked Immunosorbent Assay (ELISA) kit. At the time of blood collection, a questionnaire investigating 13 potential predisposing factors associated with C. burnetii seropositivity was completed for every dromedary camel and herd. Results were analysed by a chi-square (χ2) test and multivariate logistic regression. The seroprevalence of C. burnetii at the animal level was 71.2% (95% CI: 65.2-78.3) and 85.3% (95% CI: 72.8-97.8) at the herd level. At the animal level, differences in seroprevalence were observed because of herd size, animal age, animal sex, presence of ticks and contact with other herds. A multivariable logistic regression model identified three main risk factors associated with individual seropositivity: (1) age classgt; 11 years (OR = 8.81, 95% CI: 2.55-30.41), (2) herd sizegt; 50 head (OR = 4.46, 95% CI: 1.01-19.59) and (3) infestation with ticks (OR 2.2; 95% CI: 1.1-4.5). This study of seroprevalence of C. burnetii infection in camels in Algeria revealed a high seroprevalence of Q fever in camel populations in southeastern Algeria and provided strong evidence that Q fever represents an economic, public health and veterinary concern. Appropriate measures should be taken to prevent the spread of C. burnetii and to reduce the risk of Q fever in farm animals and humans in this agro-ecologically and strategically important region of North Africa.

The aim of the present study was to identify nutritional risk factors for the occurrence of displaced abomasum (DA) in Holstein dairy cattle raised in regions with highly variable nutritional management. Feeding program data were collected from 30 dairy farms throughout Kosovo via use of a standardized questionnaire, and an AgriNIR™ Analyser was used to analyze the nutrient composition of forage (hay, corn silage) fed to cattle on those farms. A diagnosis of DA was made via auscultation/percutation in the area of the last rib and hearing of a ping sound. Multivariate linear regression models were used to determine risk factors associated with the incidence of DA. The overall incidence of DA in this study was 4.9% (38 cases among 769 cows). Of cows diagnosed with DA, 81.6% (31/38) had left side DA and 18.4% (7/38) had right side DA. Nearly all DA occurred during the first month of the postpartum period - 92.1% (35/38); only 7.9% (3/38) were observed in the pre-partum period. Risk factors that elevated the occurrence of DA included increased intake of concentrate feed after parturition (P, Cilj istraživanja bio je identificirati čimbenike rizika u hranidbi koji doprinose pojavi dislokacije sirišta (DS) kod mliječnih goveda holštajnske pasmine, uzgajanih u područjima s različitim uvjetima hranidbe. Podatci o programu hranidbe prikupljeni su pomoću standardnog upitnika na 30 farmi za proizvodnju mlijeka širom Kosova, a analiza nutritivnog sastava u krmivima (sijeno, kukuruzna silaža) koja su na tim farmama korištena za hranidbu goveda obavljena je AgriNIR™ analizatorom. Dislokacija sirišta dijagnosticirana je osluškivanjem timpaničnog zvuka, uz primjenu metoda auskultacije/perkusije u području posljednjeg rebra. Modeli multivarijantne linearne regresije korišteni su za određivanje čimbenika rizika koji su povezani s incidencijom dislokacije sirišta. Ukupna incidencija dislokacije sirišta u ovom istraživanju bila je 4,9 % (38 slučajeva od 769 krava). Među kravama s dijagnosticiranom dislokacijom sirišta 81,6 % (31/38) krava imalo je dislokaciju u lijevu stranu, a 18,4 % (7/38) u desnu stranu. Gotovo sve dislokacije (92,1 %; 35/38) dogodile su se tijekom prvog mjeseca nakon teljenja, a samo 7,9 % (3/38) u razdoblju prije teljenja. Čimbenici rizika koji doprinose pojavnosti dislokacije sirišta uključivali su povećani unos koncentriranih krmiva nakon teljenja (P

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

The reproductive response of 27 Boran and 20 Boran x Holstein cows to an exogenous superovulation treatment regimen was investigated. Upon cessation of treatment, cows were monitored to determine the onset and duration of estrus. Superovulatory response was by assessed via both transrectal palpation and ultrasonography. The overall proportion of cows that exhibited estrus was 77% and was higher (P=0.003) for Boran than for Boran x Holstein crosses. The mean interval from CIDR removal to the onset of estrus was 20.4 ± 1.8 hours, and the mean duration of estrus was 21.9 ± 1.1 hours The method (palpation vs ultrasound) used to determine the number of corpora lutea (CL) gave similar results (P>0.10; 8.5 and 8.6, respectively). Boran cows had a higher (P

This study determined the prevalence of fetal wastage due to slaughter of pregnant camels, and the relationship between fetal wastage and factors such as breed, season, abattoir location, and age. Pregnancy characteristics of indigenous camels were also investigated. Reproductive tracts were collected from 912 female camels at two abattoirs in southeast Algeria over 2.5 years. Before slaughter, data regarding reasons for culling were obtained. Pregnancy was detected in 21.7% of camels and was higher (P

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.

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 × 10 6 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.

Bovine cumulus-enclosed oocytes were matured in vitro (IVM) in PVA-HEPES-TCM199 supplemented with 0, 0.5, 5, 50 or 500 μM cysteamine for 24 h and fertilized in vitro (IVF). After removal of cumulus cells, IVM-IVF oocytes were cultured in vitro for 8 days. Cysteamine had no effect on oocyte maturation or fertilization rates. In contrast, 5 μM cysteamine in the maturation medium enhanced subsequent in-vitro development of IVM-IVF oocytes to the blastocyst stage. Glutathione (GSH) content of oocytes cultured in medium with 0 or 0.5 μM cysteamine was significantly lower than that of oocytes before culture. When oocytes were cultured in medium with 5, 50 or 500 μM cysteamine, GSH content of oocytes remained constant (5 μM) or was significantly increased (50 or 500 μM) compared with that of oocytes before culture. These results indicate that the addition of cysteamine to a serum-free maturation medium enhances the efficiency of in vitro production of bovine embryos by maintaining GSH content of IVM oocytes.

To investigate the impacts of uterine type and conceptus genotype on development through late gestation, Meishan and Yorkshire embryos were co-transferred into the uteri of either Meishan or Yorkshire recipients that were subsequently slaughtered on Day 90 of gestation. At slaughter, regardless of conceptus genotype, fetuses and placentae were markedly smaller when recovered from Meishan than from Yorkshire recipients. Whereas Meishan and Yorkshire fetuses recovered from Meishan uteri were similar in weight, Meishan fetuses were markedly lighter than littermate Yorkshire fetuses when recovered from Yorkshire uteri. Because of the marked differences between fetal weights observed in Yorkshire recipients on Day 90 of gestation, Meishan and Yorkshire embryos were co-transferred to Yorkshire recipients that were allowed to farrow. Surprisingly, Meishan and Yorkshire fetuses cogestated in Yorkshire recipients were born at similar weights, whereas Meishan placentae were markedly smaller. The weight of Meishan placentae were similar on Day 90 and at term, whereas the weight of Yorkshire placentae were markedly larger (-70%) at term than on Day 90. The constant weight of Meishan placentae from Day 90 to farrowing appears to result from an ability to increase their vascularity during this interval. In contrast, Yorkshire placentae may be forced to increase their weight to keep pace with fetal growth during this period. Because uterine capacity sets the upper limit on litter size, the decreased endometrial surface area required per conceptus in the Meishan pig seems to explain its greater potential for increased litter size.

The objectives of this research were to determine the effects of 13-mercaptoethanol (-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 13-ME may influence embryo development. A 2 x 2 factorial treatment arrangement was used to evaluate the effect of 0 or 100 LM 3-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 13-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 initiation of treatment. The cysteine and cystine content of M199, with and without 13-ME, were determined by HPLC. Medium supplemented with 13-ME contained neither cysteine nor cystine, and it is suggested that these compounds were converted into a mixed disulfide between cysteine and PI-ME. These results indicate that 1-ME is capable of enhancing bovine embryo development in a cell-free, serum-free culture system.

Most students enroll in a baccalaureate degree program to obtain a formal education that will increase the likelihood of their obtaining employment that is challenging, rewarding, and satisfying. A student’s formal education becomes more meaningful when coupled with hands-on, industry-relevant training such as an internship or part-time job. We describe herein a multi-pronged strategy that we have employed to encourage undergraduate students to participate in an experiential learning opportunity as a part of their formal education. Based on student feedback and the high placement rate of our students, we conclude this approach has been highly effective.

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.

and Implications 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.

and Implications Embryo transfer is a reproductive technology that many livestock producers utilize as a part of their genetic improvement programs. Global use of embryo transfer technologies is increasing, and a need existed to modernize the animal science curriculum so that progressive livestock breeders would understand the intricacies of these technologies. During fall semester 1995, a two-credit lecture course in embryo transfer and related technologies was offered for the first time through the animal science department. In the fall of 1996, a 1credit laboratory course was added to the animal science curriculum to provide meaningful hands-on training in embryo transfer technologies. These two courses have provided hundreds of animal science and veterinary medicine students with theoretical and practical training in embryo transfer and related technologies in cattle, horses, pigs, sheep, and goats.