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The current study involved two experiments which were conducted at the Texas A&M Agricultural Research and Extension Center in Uvalde (semi-arid environment) from 2002 to 2004. In experiment one, Bonsmara bulls (n = 19; 20-24 mo of age) were joined with multiparous, crossbred females (n =586) for 90 d in 2003 and 2004. Bulls were allotted by selected physical traits, seminal traits, social rank, and serving capacity to one of two bull to female ratio (BFR) treatments: Conventional (1:21-1:29; n = 6 pastures) or Low (1:47-1:52; n = 2 pastures) BFR. Pregnancy rate (P = 0.33), calving rate (P = 0.26), and calving date (P = 0.22) did not differ between Conventional and Low BFR treatments. Post-breeding evaluation of bulls in 2002 (n = 16) indicated that social rank, but not seminal traits, was significantly correlated with pre-breeding values (P < 0.05). The current study demonstrates that Low BFR can be utilized in single- and multisire, 90-d breeding pastures of up to 2,090 ha without adversely affecting reproductive performance. In experiment two, yearling, one-half or three-quarter Bonsmara heifers (n = 106; 11-14 mo of age) were palpated per rectum and assigned a reproductive tract score (RTS) immediately prior to the beginning of the breeding season. Reproductive performance was measured in their two subsequent breeding years in order to estimate the value of the RTS system in extensively-managed, natural mating, 90-d breeding season programs. RTS was positively correlated (p < 0.01) with frame score (r = 0.25), age (r = 0.31), weaning weight (r = 0.47), and the weight of the heifer on the day of RTS exam (r = 0.56). The RTS means by dam parity also differed (P < 0.03). A lower (P < 0.01) percentage of females conceived during each of their first two breeding seasons for heifers of RTS 1 and 2 (65.2%) than for heifers of RTS 3, 4, and 5 (91.2%). Females with a RTS of 1 had a lower pregnancy rate over each of their first two breeding seasons, conceived later during their first breeding season, weaned lighter first calves, and remained lighter each year for fall body weight and body condition score than did heifers with RTS of 2 to 5 (P < 0.05). Collectively, the results of the current study indicate that heifers with a RTS of 1 immediately prior to a 90-d breeding season should be culled. Consideration should also be given to eliminating RTS 2 heifers, but further studies will be needed to confirm the potential economic advantage of this practice.

A series of 4 observational studies was performed on a Bovelder herd at Johannesburg Water’s Northern Farm. The heifer and cow breeding seasons started on 15 October and 1 November every year, and consisted of 50 d and 60 d of oestrus observation respectively, with once daily artificial insemination (AI). Five to 7 days after the AI period bulls were added in multi-sire groups for a period of 42 d. Pregnancy diagnoses were performed between 23 March and 26 April every year. The farming system had been in place for >25 years, with few deviations. In the first study, reproductive tract scoring (RTS) by transrectal palpation on a 5- point scale was performed 1 day before the start of breeding on a group of heifers (n = 272) born in 2002. Heifers with RTS 1 or 2 were estimated to be pre-pubertal, those with RTS 3 pubertal and those with RTS 4 or 5 post-pubertal. Pre-breeding body weight (BW) and body condition score (BCS) were recorded, and Kleiber ratio (KR) was calculated (average daily gain/end weight0.75). Heifers were followed until they weaned their first calves. The objectives of this study were to determine if RTS is a valid tool to predict reproduction and production performance in limited bred beef heifers, and to compare its predictive value with that of BW, BCS, age and KR. After adjustment for BW and age, RTS was positively associated with pregnancy rate to the 50 day AI season (P < 0.01), calf weaning weight (P < 0.01) and pregnancy rate to the subsequent breeding season (P < 0.01), and negatively associated with days to calving (P < 0.01). RTS was a better predictor of fertility than was vi KR, and similar in its prediction of calf weaning weight. It was concluded that RTS is a predictor of heifer fertility and compares well with other traits used as a predictor of production outcomes. It was further hypothesised that RTS may predict long-term reproductive performance due to its association with pregnancy outcome and days to calving after first breeding, combined with reports that heifers calving early tend to calve early in subsequent seasons and have increased lifetime production. In study 2, a 7-year longitudinal study, 292 beef cows in two age cohorts were observed from 1-2 d before their first breeding season (day of RTS), until they had weaned up to 5 calves. Years to reproductive failure was defined as the number of years until a cow failed to become pregnant during the AI season. Animals with RTS 1 or 2 were at increased risk of early reproductive failure compared to those with RTS 4 or 5 (HR = 1.4, 95% CI 1.0, 1.9) despite the fact that RTS was not associated with calving rate or days to calving after the second calving season. The predictive value of RTS was lower in the age cohort with a higher prevalence of anoestrus. Most animals with RTS 1 or 2 that were subsequently detected in oestrus were in early to mid di-oestrus at the time of scoring. It was concluded that RTS is a valid culling tool to improve long-term reproductive success in a seasonal breeding system, by excluding poor performing animals. It was further concluded that the predictive value of RTS decreases with increasing prevalence of anoestrus and at certain stages of the oestrous cycle. Apart from failure to calve, dystocia as a result of foeto-maternal disproportion is the cause of significant production loss in beef heifers. Internal pelvis area (PA) can be calculated as the product of vertical and horizontal diameter of the pelvis measured transrectally using a calliper device. In study 3, the effects of five culling strategies using prebreeding PA data on calving and dystocia rates and on pre-breeding and calf birth weight (BWT) were compared in 484 heifers. Multiple regression analyses were used to determine independent predictors of PA, calf BWT and dystocia. Hypothetical culling of 10 or 20% of heifers was applied within age cohort after ranking by each of the following: unadjusted PA (PA); PA adjusted to 365 d of age (APA); PA:BW ratio (PA:BW); PA adjusted to the median BW of the group by the regression coefficient of PA on BW(BWPA) and PA similarly adjusted to the median lean BW (LBWPA). Dam parity, calf BWT and either BWPA or LBWPA were the only independent predictors of dystocia (P < 0.05), whereas the effect of PA tended to be significant only after adjusting for calf BWT (P = 0.08). After culling by PA or APA, retained heifers were heavier, had a higher calving rate and calves tended to be heavier at birth compared to culled heifers, but dystocia rates were not different. Although culling by PA:BW resulted in lower dystocia rate, it resulted in lower pre-breeding BW in retained than in culled heifers. Culling by BWPA and LBWPA had better sensitivity and specificity for dystocia than PA, and resulted in higher calving- and lower dystocia rates in the retained heifers, without affecting the pre-breeding BW or calf BWT. It was concluded that pelvimetry is a useful culling tool to aid in the management of dystocia in yearling heifers, and that adjustment of PA to median BW within age group improves its accuracy and avoids the undesirable side-effects of using unadjusted PA. The strong association of PA with calving rate resulted in the hypothesis for study 4, namely that PA can add prognostic value to RTS as a predictor of reproductive failure in beef heifers. Transrectal ultrasound (US) examination of the reproductive tract was also investigated in this study (n = 488) with the objective of identifying which ultrasonographic measures taken at a single point in time before the onset of breeding were independently associated with reproductive outcomes. In this study pregnancy failure was defined as the failure to become pregnant after the AI and bull breeding periods while anoestrus was defined as the failure to be detected in oestrus during the entire 50 d AI period. BCS, uterus horn diameter, absence of a CL, largest follicle of less than 13mm and PA were the pre-breeding examination variables that remained in prognostic models (P < 0.1). Combining either the model based on the three remaining US measures or RTS with PA provided more accurate prognostic models for pregnancy failure and anoestrus than using RTS alone (P < 0.05). It was concluded that US measures have prognostic value for pregnancy failure in restricted bred yearling heifers as a result of their association with anoestrus, and that smaller PA has additional value to identify poor performing heifers. In conclusion, pre-breeding examination is useful to identify beef cows with lower potential to reproduce successfully over the long term in a restricted breeding system. It is recommended that PA should always be included in such examination, either unadjusted or adjusted by BW, in herds with a low and high incidence of dystocia respectively, in combination with ultrasonography of the reproductive tract. When ultrasonography is not available, the accuracy of RTS by transrectal palpation can likely be improved by repeating it in low scoring animals after 7 days. / Thesis (PhD)--University of Pretoria, 2013. / gm2014 / Production Animal Studies / unrestricted

E-&ndashcadherin (CDH1) is a cell adhesion molecule that coordinates key morphogenetic processes regulating cell growth, cell proliferation and apoptosis. Loss of CDH1 is a trademark of the cellular event epithelial to mesenchymal transition (EMT), which increases the metastatic potential of malignant cells. PTEN is a tumor suppressor gene commonly mutated in many human cancers, including endometrial cancer. In the mouse uterus, ablation of Pten induces epithelial hyperplasia, leading to endometrial carcinomas. However, loss of Pten alone does not affect longevity until around 5 months. Similarly, conditional ablation of Cdh1 alone does not predispose mice to cancer. We characterized the impact of dual Cdh1 and Pten ablation using Pgr-Cre (Cdh1d/d Ptend/d) in the mouse uterus. We observed that Cdh1d/d Ptend/d mice died at postnatal day 15-&ndash19 with massive blood loss from their reproductive tract (abnormal metrorrhagia) with prevalent vascularization in both the endometrium and myometrium. Their uteri were abnormally structured with curly horns, disorganized epithelial structure, and increased cell proliferation. Co-&ndashimmunostaining of KRT8 and ACTA2 showed invasion of epithelial cells into the myometrium. Further, the uteri of Cdh1d/d Ptend/d mice had prevalent vascularization in both the endometrium and myometrium. We also observed reduced expression of estrogen and progesterone receptors, loss of cell adherens and tight junction molecules (CTNNB1 and claudin), as well as activation of AKT in the uteri of Cdh1d/d Ptend/d mice. However, complex hyperplasia was not found in the uteri of Cdh1d/d Ptend/d. Collectively, these findings suggest that ablation of Pten with Cdh1 in the uterus accelerates cellular invasiveness and angiogenesis, and causes early death. Thus, this model does not allow sufficient time for the emergence of advanced, clinically over aggressive endometrial tumorigenesis and metastasis. Additionally, we looked at a new Cre system to ablate Pten and Cdh1 only in the epithelial cells of the uterus. Sprr2f, an estrogen dependent gene that is found highly expressed in the uterus, helps with structure and barrier function of epithelial cells. Prg-Cre turns on at postnatal day 3-5 before development of the uterus; whereas, Sprr2f-Cre is active around 3 weeks which is after uterine development. We have driven the ablation of Cdh1d/d Ptend/d using the Sprr2f-Cre. The Sprr2f-Cre Cdh1d/d Ptend/d mice successfully lived to 2 months. The Sprr2f-Cre Ptend/d mice displayed hyperplastic epithelial cells, most prominently in the glandular like structures of the uterus. Lack of cellular structure was observed in the Sprr2f-Cre Cdh1d/d Ptend/d mice. We also developed a model of orthotopic tumor transplantation to study further tumor development including cell invasion, dissemination and metastasis. The uteri of control, Cdhd/d, Ptend/d and Cdhd/d Ptend/d mice were collected and dissected to approximately ~1 mm in diameter. Then, the tissue fragments were orthotopically implanted into the uterine wall (endometrium) of wild-type syngeneic host mice. We have observed successful implantation and sustainability of the tissue through this technique. The tissue viability was successfully verified by implanting donor uterine pieces under the kidney capsule of recipient wild type mice. This study has shown that the ablation of Cdh1 and Pten in the mouse uterus initiates a more aggressive form of type I endometrial carcinoma when using Pgr-Cre as well as Sprr2f-Cre. However, neither conditional ablation approaches allowed us to fully observe the progression of the carcinoma to a metastatic disease. Our intrauterine endometrial/myometrial implantation technique proved to be an incomplete method to further study the metastatic potential of the PgrCre/+ Cdh1f/f Ptenf/f mice.

Cocaine- and amphetamine-regulated transcript (CART) is a novel family of peptides, of which CART peptide fragments 55-102 and 62-102 are reported to be the endogenous, physiologically active peptides. Immunohistochemical studies with an antiserum directed against the CART peptide fragment 55-102 revealed CART-like immunoreactive (CART-LI) nerve fibers in the rat epididymis. The number was highest in the cauda epididymis and became progressively fewer toward the caput epididymis; the vas deferens exhibited an abundance of CART-LI fibers. Injection of the retrograde tracer Fluorogold (Fluorochrome, Inc., Englewood, CO) to the junction between the vas deferens and cauda epididymis labeled a large number of neurons in the major pelvic ganglion, some of which were CART-positive. Double-labeling the ganglion sections with tyrosine hydroxylase (TH) and CART antisera revealed that CART-LI and TH-LI were expressed in two distinct populations of ganglion cells. Some of the TH-LI cells in the ganglia, however, were covered with web-like CART-LI endings. The effects of CART peptide 55-102, referred to herein as CART, on anion secretion in the form of short circuit currents (Isc) were assessed in cultured epithelia. The CART (1 to 5 μM) applied to the basolateral or apical side of the cultured epithelia caused no significant responses on Isc, whereas lys-bradykinin (1 μM) produced a large Isc response in the same preparations. Our results show that CART-LI is present in a population of rat pelvic ganglion cells, which may give rise to CART-LI nerve fibers as observed in the vas deferens and the epididymis. The biological function of CART in the rat epididymis is not known, but it apparently is not involved in ion secretion across the epithelium.

Reproductive traits evolve rapidly at the morphological, physiological and molecular levels, a taxonomically robust pattern that is thought to arise from sexual selection. In internally fertilizing organisms, female promiscuity results in competition between multiple male ejaculates for fertilizations in the same female reproductive tract, extending sexual selection past courtship and copulation. In this post-copulatory arena, biochemical interaction between male ejaculates and female reproductive tracts form a dynamic molecular interface that modulates female post-mating responses essential to reproductive fitness. Consistent with the hypothesis that these interactions are subject to sexual selection, sperm and seminal proteins are known to evolve rapidly in a broad range of taxa. The female role in this process, however, in terms of both molecular mechanisms and evolutionary dynamics, remains unclear.The presented dissertation research examines the biochemical nature and evolutionary consequences of post-copulatory sexual selection in two sister-species of cactophilic Drosophila, D. mojavensis and D. arizonae. I first present data that female post-mating response in crosses between these to species is perturbed, severely reducing the reproductive output of heterospecific crosses. A breakdown of reproductive tract interactions in matings between divergent lineages suggests that male and female contributions to reproductive outcomes are coadapted. Next, I use a combination of bioinformatic analyses, comparative sequence analyses, and biochemical assays to elucidate candidate female reproductive tract proteins that may be involved in ejaculate-female dynamics. 241 candidate female reproductive proteins are identified, the most intriguing of which are recently-duplicated secreted proteases. Finally, I explore the evolutionary history of two families of secreted proteases within geographically isolated populations of D. mojavensis. I show that both families evolve rapidly through a complex process involving gene duplication, gene conversion, pseudogenation and positive selection, a unique pattern never before documented in reproductive proteins.Collectively, my dissertation research suggests that females are active participants in the evolution of reproductive tract interactions. Further exploration of how sexual reproduction coevolves between males and females, both in terms of interacting biomolecules, and dynamic evolutionary histories, remains an important challenge for future research.

Philosophiae Doctor - PhD / The sexual behaviour of youths is believed to play a role in the spread of SexuallyTransmitted Infections (STIs) and Reproductive Tract Infections (RTIs). This study examinesthe determinants of youth sexual behaviours and knowledge of reproductive tract infections (RTIs) and sexually transmitted infections (STIs) in Malawi. It explores rural/urbandifferentials in sexual behaviours using indicators such as early sexual initiation, multiplesexual partnerships, and non-use of condoms, in order to establish policy recommendationstoward improving sexual behaviour among youths. The Malawi Demographic Health Survey2010 data was used. Out of a sample of 2987 males and 9559 females aged 15-24 years,5652 females and 1405 males (condom use), 675 females and 511 males (inconsistentcondom use), 6470 females and 2026 males (multiple sexual partnerships (MSP)), and 15217females and 1405 males (early sexual debut) were filtered in the study.Chi-square and logistic regression techniques were performed to test for association betweensexual behaviour indicators and socio-demographic variables. The prevalence of non-use ofcondom was higher among catholic females (OR=1.11), lower among Muslim males (OR=0.81) and higher among CCAP females (OR=1.19). Muslim females were (OR=1.42) more likely to initiate sexual activities early, while Muslim males were (OR= 0.57) less likelyto initiate sexually activities early. Females in the central region (OR=1.51) and catholicmales (OR=1.63) were more likely to have more sexual partners.Encouraging these young people to be faithful to one uninfected partner, abstinence fromsexual activities, use condoms consistently and delay sexual initiation will help curb the spread of STIs in Malawi.

Master of Science in Veterinary Biomedical Science / Department of Clinical Sciences / Robert L. Larson / The selection of young replacement animals can have a significant impact on beef herd reproductive performance. Replacement heifers can be utilized to improve reproductive performance by replacing mature animals that failed to meet the production with young, cycling heifers that can have the potential of improving the reproductive momentum of a herd. The use of yearling bulls in natural breeding herds has the advantage of shortening the generational interval of the herd and has the potential of reducing the cost per cow exposed as additions to the bull battery. This thesis involves two studies that investigated methods used for the selection of peripubertal replacement animals in beef herds. The first study evaluated the ability of the novel Ready-Intermediate-Problem (RIP) replacement heifer evaluation matrix to classify heifers into groups that allow producers to select for replacements that meet production goals. Beef heifers (n=341) were classified according to the RIP matrix guidelines and then exposed to AI breeding, bull breeding, or a combination of both as per the management plans for each participating herd. Following breeding season the heifers were evaluated to determine pregnancy status, pregnancy status to single AI exposure, days bred, and the number of 21 day cycles needed during breeding season to become pregnant. After breeding season, 298 (87%) of the heifers were pregnant, 204 (68%) of which became pregnant in the first 21 days of the breeding season. Probability of overall pregnancy and pregnancy after single AI exposure was not significantly associated with RIP classification. There was a significant interaction in RIP classification by 21 day cycle. The second study was a retrospective study using BSE result data to determine the proportion of yearling beef bulls that are classified as satisfactory potential breeders when reevaluated after failing their initial breeding soundness evaluation (BSE) and to identify any predictive factors at initial BSE for satisfactory performance at revaluation. The study included 2,805 beef bulls between 11 and 14 months of age at first BSE evaluated at KABSU from 2006 to 2014. Generalized linear mixed models were created to assess potential associations among breed, age, and interaction between breed and age and passing the initial evaluation and identify predictive factors for risk of passing BSE after initial failure. The majority (93%) of the study bulls passed one of up to three BSEs. There was a significant interaction between age and breed of bull at initial BSE. Identification of suitable peripubertal replacement animals that will improve herd reproductive performance remains a challenge for producers. There are several factors that can affect replacement animals’ ability to perform according to expectations at the beginning of the breeding season. Classification of heifers into categories that can predict performance during breeding season with reasonable confidence can assist producers in identifying heifers that complement the reproductive performance goals of the herd. Utilizing BSE to identify bulls that have adequate semen quality as well as other traits important for breeding soundness is similarly important in reducing the risks of using young bulls for breeding.

In this study 272 beef heifers were studied from just prior to their first breeding season (15 October 2003), through their second breeding season and until just after they had weaned their first calves in March 2005. The study consisted of two main parts: in the first part, heifers were randomly allocated to either a synchronised TEST group or an unsynchronised CONTROL group. The TEST group received artificial insemination (AI) for 6 days followed by prostaglandin F2á (PGF) treatment on day 6 (PGF/6) and further AI for a total of 50 days, which was followed after a 6 day break by a 42 day bull breeding season. The CONTROL group were bred for the same period without PGF treatment. Synchronisation resulted in a reduction in days to first insemination (P < 0.01) and days to calving (P = 0.04). No significant difference could be demonstrated in pregnancy rate to the 50 day AI season (60.0% vs. 51.8%, TEST and CONTROL groups respectively, P = 0.18), final pregnancy rate (82.2% vs. 83.2%, P = 0.87) or pregnancy rate to the subsequent breeding season (96.0% vs. 95.0%, P = 1.00). A significant increase in mean weaning mass of the calves due to synchronisation could not be demonstrated (207.0 kg vs. 201.4 kg, TEST and CONTROL groups respectively, P = 0.32). However, data from this study were used to calculate the benefit:cost ratio, and a value of 2.8 was reached, representing the return on investment for the synchronisation protocol under these circumstances. It was concluded from this study that a PGF/6 protocol may lead to a change in the total mass of calves weaned by changing days to calving and thus weaning mass, birth mass of calves, weaning rate and/or the ratio of male:female calves born. It was further concluded that a practical way to predict the cost effectiveness of an oestrus synchronisation protocol is to determine the ratio between the total cost of the programme and the price of weaner calves per kg live mass. This ratio represents the minimum increase in mean weaning mass that has to be achieved for the programme to be cost effective if no increase in weaning rate is achieved. In the second part of this study, reproductive tract scoring (RTS) was performed on the same group of heifers one day before the onset of their first breeding season. The effect of RTS on several reproduction and production outcomes was tested, and the association of RTS with the outcomes was compared to the associations of other input variables such as mass, age, body condition score (BCS) and Kleiber ratio using multiple or univariable linear or logistic regression. RTS was associated with pregnancy rate to the 50 day AI season (P < 0.01), days to calving (r = 0.28, P < 0.01), calf weaning mass (r = 0.22, P < 0.01) and pregnancy rate to the subsequent breeding season (P < 0.01). These associations were mostly independent of associations with mass, age and BCS before the onset of the first breeding season. RTS was a better predictor of fertility than was Kleiber ratio, and similar in its prediction of calf weaning mass. It was concluded from this study that RTS is a unique predictor of heifer fertility, compares well with (but is independent of) other traits used as a predictor of production outcomes and is likely to be a good predictor of life production of the cow. / Dissertation (MSc (Veterinary Sciences))--University of Pretoria, 2006. / Production Animal Studies / unrestricted

Worldwide, more than half of all HIV-infected individuals are women. Since mucosal surfaces are the primary gateway for HIV entry, maintaining the integrity of the female reproductive tract (FRT) is essential for preventing infection. The FRT employs many immune mechanisms that serve as the first line of defense against HIV transmission. Among these are vaginal fluid secretions rich in antimicrobial peptides, and commensal bacteria that colonize the vagina and prevent infections. We sought to study vaginal fluid as an innate immune component of the FRT in the prevention of HIV infection. Additionally, we investigated the anti-HIV microbicide candidate RC-101 as a possible treatment against pathogenic bacteria that disrupt the healthy microbiota of the FRT and create a suboptimal immune state that increases host susceptibility to viruses, such as HIV. Here we report that vaginal fluid collected from healthy females inhibits HIV infection. Moreover, our studies reveal that vaginal fluid collected from Black and White women exhibit disparate anti-HIV activity, possibly rendering Black women more susceptible to HIV infection. In addition, we show that RC-101, which is active against HIV, can also inhibit pathogenic bacteria that compromise FRT innate immunity, providing a dual mechanism of protection against HIV acquisition. Overall, these findings show that vaginal fluid is an important part of female innate immunity that protects the host from heterosexual HIV acquisition. Furthermore, the microbicide RC-101 may prevent HIV infection by both directly preventing viral entry, and by restricting the growth of pathogenic bacteria that disrupt the protective commensal vaginal flora. Together, innate mechanisms and bolstered protection present a multifaceted approach to maintaining effective host immunity.