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Intrauterine crowding and placental insufficiency are main reasons for prenatal losses in swine. Two studies were conducted to examine: 1) conceptus development and in vitro steroidogenic capability of three regions of the placenta (middle, inner, polar) at d 30, 50, 70, and 90 of gestation; and 2) the effects of intrauterine position and fetal sex on conceptus development and in vitro steroidogenic activity of the placenta and endometrium at d 40, 60, 80, and 100 of gestation. All variables were examined in gilts that were uterine intact before hysterectomy (n=19) and in gilts unilaterally hysterectomized-ovariectomized (UHOX) before breeding (n=17) to induce intrauterine crowding. Placentas were combined according to the sex of the fetus associated with the placental unit (except at d 30). Placentas were sectioned into middle, inner and polar regions. Placental tissues were incubated, and release of progesterone (P₄) and estrone (E₁) was determined. Fetal survival rate was greater (P< .01, .05, .001 at d 50, 70 and 90, respectively) from intact versus UHOX gilts. Placental length and weight, fetal length and weight, and allantoic fluid volume were greater in intact compared to UHOX gilts. The polar region of the placenta released less P₄ than the other regions at d 50, 70 and 90. Uterine status (P< .005) affected P₄ release only at d 90. Sex of the fetus did not affect placental P₄ release. Region of the placenta affected E₁, release at d 30 (P< .01) and d 50 (P< .06). Uterine status did not affect E₁ release. Sex of the fetus affected (P< .001) E₁ release only at d 50. In the second study, a total of 45 gilts was used. Placentas and endometrium were combined based upon the intrauterine position of the associated fetus. Placental and endometrial tissues were incubated and release of P₄ and E₁ was determined. Uterine status (intact or UHOX) did not affect the variables measured. Intrauterine position affected fetal and placental weights (P< .02 and .01, respectively) at d 40 of gestation. No significant effect of intrauterine position was detected on placental and endometrial P₄ release. At d 100 of gestation, placentas associated with fetuses bordered in utero by fetuses of the same sex released more (P< .01) E₁ compared to placentas associated with fetuses bordered by fetuses of the opposite sex. Estrone release by the endometrium was not significantly affected by intrauterine position. Only trace amounts of testosterone and dehydroepiandrosterone sulfate were measured in the fetal fluids at all days of gestation. Intrauterine position had no effect on P₄, E₁ or androstenedione concentrations in fetal fluids. Collectively, the results indicated a) a differential release of P₄ and E₁ by the three regions of the placenta at certain days of gestation, b) no compensatory increase in placental steroidogenic activity per unit of tissue when total placental mass was reduced, and c) a limited effect of intrauterine position on placental and endometrial steroidogenesis at various days of gestation. / Ph. D.

The effects of dietary folic acid supplementation on serum folate status, conceptus development and reproductive performance in gilts and sows was investigated in a series of experiments. The specific objectives of the study were to: 1) to study the serum folates profile following rapid consumption of a single meal containing different levels of supplemental folic acid; 2) to study the effects of maternal folic acid supplementation on conceptus survival, growth and development prior to mid-gestation in gilts and sows; and 3) to study the effects of multiple levels of dietary folic acid supplementation on sow reproductive performance over four successive parities. In the first experiment (Chapter III), gilts fed a single, rapidly consumed meal, had a rapid increase in serum folates concentration during the first hour postprandial. Within eight hours after feeding, serum folates in the gilts had returned to near prefeeding levels. The results also suggest that supplementing the diet with increasing levels of folic acid over a range of 0 to 4 ppm results in more rapid postprandial uptake and elimination of folic acid from general circulation. In the second experiment (Chapter IV), supplementing the diet of first parity and third parity breeding sows with 2 ppm folic acid had no effect on litter size at day 45 of gestation. However, several measurements associated with placental and fetal growth were increased with folic acid supplementation. Results of a fifth parity trial with four levels of supplemental folic acid were variable and inconclusive. The implications of increased placental and fetal growth up to day 45 of gestation in the first and third parity sows is discussed. In the third experiment (Chapter V), a decline in serum folate concentration in pregnant sows from mating to mid- to late gestation was clearly demonstrated. Supplementing the sow's diet with folic acid over a range of 0 to 4 ppm resulted in a linear increase in serum folate concentration at mating, during gestation and at weaning. However, under the conditions of this experiment, folic acid supplementation had no significant effect on sow reproductive performance. / Ph. D.

The purpose of this study was to investigate the effect of intrauterine position and its possibly resultant steroid differential on conceptus growth and steroid content in allantoic and amniotic fluid of pigs. six conceptus variables (placental weight, placental length, fetal weight, fetal length, allantoic fluid volume and amniotic fluid volume) and seven steroids (progesterone, androstenedione, dehydroepiandrosterone, dehydroepiandrosterone sulfate, testosterone, estrone and estrone sulfate) were evaluated. Four fetal positions were studied: females between females (f2F), females between males (fOF) , males between females (m2F) and males between males (mOF). Fetuses examined from ovariectomized (OVX) pregnenolone (PS)-treated gilts showed differences in placental weight, allantoic fluid estrone and androstenedione content and amniotic fluid androstenedione content as a result of intrauterine position. Fetuses from OVX gilts treated with either medroxyprogesterone acetate (MPA) I or progesterone (P4) showed differences in placental length due to intrauterine position. Allantoic and amniotic fluid content of any of the steroids studied from OVX MPA- and P4-treated gilts was not altered as a result of intrauterine position. Intrauterine position appears to have a definite influence on conceptus development and possibly on steroid content. However, discrepancies' of results among trials possibly as a result of differences in type and amount of exogenous precursor enable us to draw stronger conclusions on the intrauterine position effect. / Master of Science

This investigation is a series of four experiments that examine the role of intrauterine steroidogenesis in the pregnant gilt. In chapter 3, ovariectomy (OVX) and medroxyprogesterone acetate (MPA) treatment at two stages of gestation (d19-29 or d59-69) resulted in maintained pregnancy, normal fetal survival rates, normal conceptus development, and typical plasma estrogens when compared to intact, control gilts. In chapter 4, intrauterine steroid synthesis was quantitated by incubating placenta (PLAC) and endometrium (ENDO) from the control and MPA-treated gilts of chapter 1. Placental P₄, estrone (E₁), and estrone sulfate (E₁SO₄) concentrations were significantly higher than ENDO. Progesterone (P₄) production increased between d30 and 70 of pregnancy while E₁ and E₁SO₄ decreased. The addition of pregnenolone (P₅) to the incubation medium enhanced P₄ but not E₁ or E₁SO₄ release. MPA-treatment had no effect on in vitro steroid production. In chapter 5, OVX gilts from 9 stages of gestation (d20, 25, 30, 35, 40, 45, 55, 60, 80 and 90) were administered P₅ until undergoing hysterectomy (10d after OVX). Only 1 of 10 gilts OVX on d20 or 25 was able to maintain pregnancy for the entire treatment period. The pregnancy rate was variable (67-100%) for gilts OVX between d30-45 of gestation and 100% for gilts OVX subsequent to d45. All measures of whole litter survival and conceptus development for gilts that maintained pregnancy were equivalent to those expected under ovarian-intact, untreated conditions. Plasma steroid levels were relatively normal but allantoic P₄ failed to increase late in gestation. In chapter 6, in vitro steroid synthesis by PLAC and ENDO from gilts treated in chapter 5 was evaluated. Placental P₄ production increased as gestation progressed while ENDO P₄ production was low throughout. The addition of P₅ to the incubation medium resulted in increased P₄ synthesis for both tissues at most stages of gestation. Extending the incubation period also resulted in increased P₄ production at several stages of pregnancy. In vitro estrogen production increased markedly as gestation progressed past d65. The addition of P₅ and extended incubation time enhanced E₁ but not E₁SO₄ synthesis. Overall, data indicate that the PLAC and ENDO have a large capacity for steroid synthesis and estrogen synthesis can occur de novo in the absence of ovarian precursors. / Ph. D.

In der Schweinezucht werden konventionell 1-3 x109 Spermien als Frischsamen in einem Volumen von 80-100 ml intrauterin versamt. Im Vergleich zur Rinderbesamung, bei der mitunter 2 x106 Spermien zu Trächtigkeiten führen, sind Ejakulate von Ebern ineffizient. Die einzige Möglichkeit geringe Spermienzahlen erfolgreich zu versamen besteht darin die Spermienablage nahe dem Ort der Befruchtung im distalen Isthmus des Eileiters durchzuführen. Die spezies-spezifische Bindung von Säugerspermien an diverse Oberflächenzellen des weiblichen Traktes, die der Kapazitation und Hyperaktivierung vorangehen, setzt die Erkennung von Kohlenhydraten durch lektin-ähnliche Proteine der Spermienplasmamembran voraus Daher wurde vermutet, dass eine mutmaßliche Bindung porziner Spermien an das Uterusepithel ebenfalls Protein-Kohlenhydrat vermittelt ist. Ziel der vorliegenden Arbeit war die Etablierung eines Zellkulturmodells aus primären Uterusepithelien der Sau (Sus scrofa), um mögliche Gründe für die hohen Spermienzahlen in der Schweinbesamung zu untersuchen und zu identifizieren. Porzine uterine Epithelien wurden mittels Verdau mit Trypsin/EDTA (1x) gewonnen. Zellen wurden auf Collagen (rat tail, type I) auf Kollagen-beschichteten Deckgläschen aus Glas in 6-Well Kulturschalen ausgesät. Die Anheftung der Zellen an die Kollagen-Matrix wurde nach 12-36 Stunden beobachtet. Erste Kolonien bildeten sich nach fünf bis sieben Tagen und Konfluenz wurde nach zehn bis fünfzehn Tagen erreicht. Der Nachweis der Zellart erfolgte mittels Immunfluoreszenz-Färbung mit einem Epithelien-spezifischen Antikörper (anti-Cytokeratin-19). Eberspermien banden innerhalb weniger Minuten an die UEC und verblieben währenddessen motil. Eine verringerte Spermienbindung wurde sowohl auf Aortenendothelien als auch fötalen Fibroblasten des Schweins beobachtet. Dies weist auf das Vorhandensein spermienspezifischer Liganden auf den UEC hin. Spermien, wie auch UEC wiesen hohe Bindungsintensitäten für Lektine die an Glc-NAc, (WGA) sowie Gal-NAc (sWGA) binden. Die Sättigung von Sialinsäure führte zu einer stark verminderten Spermienbindung auf den UEC. Bei einer Sättigung von Glc-NAC wurde kein Unterschied beobachtet. Dies kennzeichnet Sialinsäure als den vermutlich wichtigsten Kohlenhydratrest in der Spermien-Epithelzellbindung.

Pre-pubertal pig oocytes possess lower developmental competence than those from adult pigs following in vitro maturation (IVM). Previous studies have demonstrated that exposure of pre-pubertal oocytes to 1 mM dibutyryl cAMP (dbcAMP), a membrane permeable cyclic adenosine monophosphate (cAMP) analogue, for the first 20 h of IVM improves the rate of blastocyst development. Developmental competence of in vitro matured pig oocytes has been reported to increase with increasing follicle size. In this thesis, experiments were carried out using pre-pubertal and adult pig oocytes to investigate the relationship between donor age, intra-oocyte cAMP level and follicle size in terms of oocyte maturation and developmental competence. These experiments demonstrated that, while ovarian, follicular and oocyte morphology are immediately altered with the onset of puberty, pre-pubertal oocytes must be exposed to more than the first oestrous cycle to achieve improved developmental competence in vitro. Later experiments demonstrated that pre-pubertal oocytes accumulate less cAMP during IVM, undergo more rapid meiotic progression and display reduced rates of blastocyst development compared to in vitro matured adult oocytes. Treatment with dbcAMP for 22 h IVM increased the cAMP content of pre-pubertal oocytes, slowed meiotic progression during IVM and improved the rate of blastocyst formation. While the cAMP concentration of pre-pubertal oocytes was increased to levels similar to that of adult oocytes, rates of blastocyst formation remained lower, suggesting that additional factor(s) are required for oocyte maturation. This thesis also examined the follicle size cohorts that make up the 3-8 mm aspiration range on pig ovaries. The surface of pre-pubertal ovaries contained around double the number of 3 mm follicles compared with adult ovaries. Blastocyst development of pre-pubertal oocytes increased with increasing follicle size and was highest using oocytes from 5-8 mm follicles, while adult oocytes from all follicle size cohorts displayed similar high rates of blastocyst formation. The interaction between follicle size and cAMP content in pre-pubertal oocytes was examined next. Cumulus-oocyte complexes (COCs) from 3 mm follicles accumulated less intra-oocyte and inter-COC cAMP and displayed reduced cumulus expansion compared with COCs from 5-8 mm follicles. While dbcAMP treatment increased the cAMP content of oocytes from 3 mm follicles, it had no effect on the cAMP content of the whole COC. These findings suggest that inadequate levels of intra-oocyte cAMP during IVM contribute to the low developmental competence of pre-pubertal oocytes from 3 mm follicles, suggesting that cAMP transfer, production or degradation processes are incomplete. Analysis of steroid content from different follicle size cohorts revealed that the progesterone content of prepubertal follicular fluid (FF) increased with increasing follicle size, yet overall was lower than that of adults. This suggests that differences may exist in the gonadotropinstimulated steroidogenic activity of granulosa cells of pre-pubertal COCs from different follicle sizes. Since progesterone secretion did not differ between pre-pubertal and adult COCs, it appears that the downstream pathway from the granulosa cell response rather than the actual quantity of progesterone is important for subsequent maturation processes. These studies then examined gap junction communication (GJC) within the pre-pubertal COC during IVM to examine whether the positive effects of increasing follicle size and dbcAMP on intra-oocyte cAMP levels relates to improved cAMP transfer between the cumulus cell layer and oocyte. Cumulus cell-oocyte GJC during IVM was maintained for a longer period in pre-pubertal COCs from 3 mm follicles than in those from 5-8 mm follicles. Treatment with dbcAMP had minimal effect on GJC in either COC type, thus the dbcAMP-induced increase in intra-oocyte cAMP levels appears independent of GJC. Differences in GJC during IVM together with the COCs ability to increase intraoocyte cAMP levels during IVM, suggests that differences may exist in the quantity of gonadotropin receptors, which are responsible for cAMP production, within the cumulus layer of COCs from 3 mm compared with 5-8 mm follicles. In conclusion, this thesis has demonstrated that an increase in intra-oocyte cAMP is necessary during maturation for completion and synchronisation of maturation and high developmental competence of the pig oocyte. Comparison of 3, 4 and 5-8 mm follicle sizes in the pre-pubertal pig, as described here, provides an excellent model for further investigation into the role of cAMP and the other factors required for co-ordination of oocyte nuclear and cytoplasmic maturation and subsequent embryo production. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1297309 / Thesis (Ph.D.) -- School of Paediatrics and Reproductive Health, 2007

The impact of within-litter weight variation on the productivity of pig enterprises is poorly understood. The objective of the study was to determine the effect of within-litter birth weight variation on litter performance at three weeks of age and at weaning. The study was conducted using records from 1 788 litters, collected between January 1998 and September 2010, from a pig herd at the Agricultural Research Council (ARC), Irene. The records consisted of piglet identity, breed of sow, breed of boar, parity number, date of farrowing, number of piglets born alive (NBA), individual piglet weight at birth, three weeks and at weaning. From these records, mean birth weight (MBWT), litter weight at birth (TBWT), within-litter birth weight coefficient of variation (CVB), minimum birth weight (MinB) and maximum birth weight (MaxB) were calculated. Mean weight at three weeks (MWTT), litter weight at three weeks (LWTT), within-litter weight coefficient of variation at three weeks (CVT), percent survival to three weeks (SURVT), mean litter weaning weight (MWWT), litter weight at weaning (LWWT), within-litter weaning weight coefficient of variation (CVW) and percent survival at weaning (SURVW) were computed as derivatives. The factors affecting CVB were analysed using the General Linear Model procedures (SAS, 2008). For the relationships between CVB and litter performance at three weeks and weaning, PROC STEPWISE was used. The PROC REG (SAS, 2008) was then used to test whether the relationships between CVB and CVT, SURVT, MWTT, LWTT, CVW, SURVW, MWWT, LWWT and LWWT. Multiparous sows farrowed litters with higher (P<0.05) CVB than gilts. The litter weight (TBWT) and NBA, fitted as covariates, also affected (P<0.05) CVB. The correlation between CVB and NBA was 0.30. The CVB had a linear relationship (P<0.05) with SURVT (SURVT = 83.21 - 0.20 CVB), CVT (CVT = 16.71 + 0.50 CVB), SURV (SURW = 87.9 – 0.04CVB) and CVW (CVW= 15.8 + 0.5CVB). An increase of CVT with CVB depended on parity (P<0.05). The rate of increase of CVT with CVB was highest in Parity 1 (b=0.41) followed by Parity 2 (b=0.36) then middle aged (Parity 3-5) sows (b=0.32). The CVB had no effect on MWTT, LWTT, MWWT and LWWT (P>0.05). The CVB was shown to be an important determinant of SURVT and SURVW. A uniform litter at birth is likely to lead to a homogenous litter at three weeks and weaning, thereby reducing costs of production. Pig producers should, therefore aim at producing homogenous litters at birth. / Thesis (M.Sc.Agric.)-University of KwaZulu-Natal, Pietermaritzburg, 2011.

Within the past 30 years, through ongoing technology and portability developments, real-time (b-mode) ultrasonography (RTU) has increasingly become a valuable diagnostic tool in assessing the female reproductive tract in swine. Initially applied in swine production to visually determine pregnancy status, RTU use has expanded to include assessment of the peri-pubertal and mature non-pregnant females as well. Transabdominal and transrectal modalities to visualizing the reproductive tract in swine have been reported with the transabdominal approach more common due to the fact of its ease of accessibility, animal/personnel safety, and reduced time to perform. Adjustable frequency transducers are preferred as they allow optimization of image quality at various depths. If a single transducer frequency must be selected, a 5 MHz probe provides the best versatility for visualizing the reproductive tract in swine. Other basic requirements for ultrasound equipment which will be used on commercial swine farms include being light weight and easy to handle, readily cleanable and disinfectable, long battery-life, and good durability. When using RTU for pregnancy determination, diagnosis is based upon a combination of the animal’s breeding records, the presence of embryonic fluid, and, depending upon gestational stage, fetal structures. If RTU is used as a diagnostic tool in assessing reproductive problems in an individual or a group of animals, sonographic evaluation of both the uterus and ovaries is performed. Tissues are delineated and assessed based upon their echogenicity, echotexture, and size. Uses of RTU in clinical practice may include assessment of delayed puberty, prolonged wean-to-estrus interval, absence of post-weaning estrus, herd disruptions in conception and farrowing rates, vulval discharge, peripartum and puerperal disorders. This review aims to provide an overview on principles and clinical uses of RTU with respect to application to address female reproductive performance issues in commercial swine operations.

The present studies were conducted to gain a better understanding of the effects of pregnenolone (P₅), human chorionic gonadotropin (hCG) and 3' 5', cyclic adenosine monophosphate ( cAMP) on porcine placental and endometrial production of progesterone (P₄), testosterone (T) and estrone (E₁) at 30, 60 and 90 days of gestation. Duplicate 300 mg samples of placenta, endometrium or both (co-incubation) were incubated in medium199 containing either no P₅, P₅, P₅ + hCG or P₅ + cAMP for either zero (control), .5, 1 or 2 h. The first study compared P₄ and E₁ production with or without addition of P₅. At d 30, 60 and 90, respectively, P₄ production (ng/g) increased significantly in the presence (vs absence) of P₅ in the incubation medium of placental (13.2 vs 7.5, 73.9 vs 42.7, 137.4 vs 113.5, respectively) coincubation (14.5 vs 10.0, 33.6 vs 22.3, 77.9 vs 49.4, respectively) and endometrial (16.0 vs 13.3, 23.0 vs 16.0, 17.1 vs 6.7, respectively) tissue. Presence of P₅ increased E₁ production in d 60 (1.3 vs .7 ng/g) and d 90 (51.7 vs 34.6 ng/g) placental tissue and d 90 endometrial tissue (9.8 vs 8.0 ng/g). In a second study, P₅ + cAMP increased (vs P₅ alone) P₄ in placental tissue at d 30 (11.6 vs 8.7 ng/g) and coincubation tissue at d 90 (103.7 vs 75.3 ng/g). Cyclic AMP stimulated increased P₄ synthesis ( vs P₅ alone), throughout the incubation period in d 60 and d 90 tissue. E₁ production by endometrial tissue at d 30 (4.1 vs 2.9 ng/g), and placental tissue at d 60 ( 1. 2 vs . 9 ng/g). Presence of hCG in the incubation medium had no overall effect on either P₄ or E₁ accumulation. Only trace amounts of T were detected in either study, suggesting rapid aromatization of C₁₉ steroids to estrogens. / M.S.