Doctor of Philosophy / Department of Animal Sciences and Industry / Barry J. Bradford / Jeffrey S. Stevenson / Four experiments were conducted to assess nutritional and hormonal strategies to improve fertility in lactating dairy cows. In experiment 1, metabolites (-4, -2, +1, +2, +5, and +7 wk) and steroid hormones in ovarian follicular fluid (FF) and blood serum (BS) were examined in Holstein cows (n = 59) individually fed Saccharomyces cerevisiae fermentation product from -4 through +7 wk (calving = wk 0). Neither metabolites nor hormonal concentrations in BS or FF differed between treatments. In experiment 2 a rumen-protected glucose (RPG) product was supplemented at varying doses in the diet of lactating dairy cows with the objective to increase concentrations of glucose and insulin resulting in decreased activity of liver cytochrome P450 2C and P450 3A, thus increasing blood progesterone concentration. Neither pre-feeding nor post-feeding concentrations of glucose differed among treatments. Pre-feeding insulin did not differ among treatments, but a difference in the concentration of insulin (postprandial minus pre-prandial) was detected (P = 0.01). The increase in insulin was greater in control cows relative to the mean of the 3 RPG doses. We conclude that the insulin response to the RPG diets was diminished relative to the control. Supplementation with RPG did not impact concentrations of progesterone. Experiment 3 tested: (1) a shortened version of Ovsynch (SS: GnRH-1 -7 d - PGF2α - 24 h - PGF2α - 32 h - GnRH-2 - 16 h - AI) that excluded GnRH-1 to resynchronize ovulation in cows bearing a corpus luteum (CL) after a non-pregnancy diagnosis (NPD); (2) the value of including progesterone-releasing intravaginal insert + Ovsynch (OVS + CIDR) in absence of a CL compared with presence of a CL + OVS; and (3) the accuracy of detecting a functional CL by transrectal ultrasonography. Pregnancy per AI (P/AI) risk tended (P = 0.09)) to be greater for OVS than SS but did not differ from OVS + CIDR at 32 d (30.3% [n = 644], 25.7% [n = 678], and 25.9% [n = 270]), respectively. In SS cows, P/AI was greater (P = 0.01) when cows had a functional CL (progesterone was ≥ 1 ng/mL) vs. a nonfunctional CL at d 0, but did not differ from OVS cows. Short synch is a viable alternative to an entire OVS treatment when CL status is accurately detected. Experiment 4 was performed in 2 herds to determine if administering PGF2α concurrent with timed artificial insemination in lactating dairy cows would enhance P/AI. Pregnancy per AI at d 32 and 80 did not differ between treatments. Cows treated with PGF2 alpha in one herd produced more twins than control cows (11.7 vs. 3.2%), whereas no treatment difference was detected in the second herd (5.6 vs. 5.6%), respectively. We conclude that i.m. treatment of lactating dairy cows with 10 mg of PGF2α concurrent with timed AI did not improve P/AI or embryo survival, but increased twinning in one herd. Further research is warranted to determine nutritional and hormonal strategies to improve fertility.

The reproductive lifetime of a woman is limited primarily by her age. The state of an oocyte represents the central determinant of the fate of an ovarian follicle as well as embryo development throughout maturation. Oocyte reserve and oocyte quality are two major determinants of the likelihood of achieving pregnancy for a woman. Assisted Reproductive Technology (ART) has provided a valuable alternative for women attempting to conceive at an older age, however even with ART the likelihood of a live birth also decreases with increased age. Mammalian oocytes undergo meiotic maturation in preparation for ovulation and fertilization. Throughout most of its lifetime the oocyte remains arrested in the dictyate stage of prophase of meiosis I (MI), also called the germinal vesicle (GV) stage, until the follicle receives a hormonal signal to progress through meiosis. Only a small fraction of the follicles present in the ovaries receive this signal, while the rest remain unresponsive. The DNA damage response (DDR) is activated in the presence of double stranded breaks (DSBs) in DNA and can induce various cellular responses including senescence or cell cycle arrest, and/or apoptosis, also known as programmed cell death. Telomeres mediate senescence in most cells. Telomeres consist of tandem DNA repeats and associated proteins, which cap and protect chromosome ends. Telomeres and their associated proteins form a loop at the ends of chromosomes, which buries them. This telomere complex is called shelterin. Shelterin prevents the ends of chromosomes from triggering a DNA damage response. However, with each round of DNA replication chromosomes lose small segments of their telomeres. Telomere attrition also can arise in non-dividing cells via the action of oxygen radicals. We hypothesize that germinal vesicle arrest, which occurs in some oocytes retrieved for ART that fail to progress through meiosis, is associated with telomere attrition and the associated cellular senescence pathway induced by DNA damage. Previous studies have identified higher levels of DNA damage foci in isolated GV arrested oocytes compared to those that progress through the meiotic cell cycle. Our studies confirm the presence of the DNA damage response (DDR) regulator, ATM, at higher levels in GV stage oocytes versus those that have matured to later stages. Immunostaining shows a near 50% increase in presence of ATM in arrested oocytes. Confirming the role of the DDR in cell cycle arrest during oocyte maturation could highlight a new target for strategies to improve ART technology and increase the likelihood of achieving pregnancy later in life.

Thesis (M.S.)--Boston University / PLEASE NOTE: Boston University Libraries did not receive an Authorization To Manage form for this thesis or dissertation. It is therefore not openly accessible, though it may be available by request. If you are the author or principal advisor of this work and would like to request open access for it, please contact us at open-help@bu.edu. Thank you. / 2031-01-01

The purpose of this thesis are to determine the economic forces influencing birth rates in Utah and to compare their influences with those found in similar studies for the United States. To do this, an economic model describing fertility behavior was used. Data for the model was collected primarily from Census Bureau reports for the year 1970.

Previous research has shown that sperm mobility is a primary determinant of fertility in fowl. Sperm mobility denotes the net movement of a sperm population, and males can be characterized by phenotype. Sperm acylcarnitine content differs between low and high sperm mobility phenotypes. The release of acyl groups from phospholipids within sperm depends on the action of the enzyme phospholipase. Inhibition of phospholipase A��� (PLA���) activity eliminates sperm motility, thereby rendering sperm immobile. This research was performed to test whether cPLA��� was expressed differentially in roosters characterized by low or high sperm mobility phenotype. cPLA��� expression in the two phenotypes was compared using reverse transcription - polymerase chain reactions. The cDNA amplified was a 352 nucleotide fragment encoding the Ca����� binding domain of cPLA���. Two sequential experiments were performed using full- and half-sib roosters. In the first experiment (n=3 full�� sibs per phenotype), cPLA��� expression was greatest in testes from the high phenotype relative to ��-actin or 18S rRNA (P < 0.05 and P < 0.0057, respectively). The average cPLA��� : ��-actin ratios for high and low sperm mobility phenotypes were 0.63 �� 0.260 (mean �� SEM) and 0.32 �� 0.123, respectively. The cPLA��� : 18S rRNA average ratios were 0.74 �� 0.158 and 0.38 �� 0.135 for high and low sperm mobility phenotypes, respectively. In the second experiment (n=6 half-sibs per phenotype), the high mobility phenotype also showed greater (P < 0.023) expression of cPLA��� relative to the 18S rRNA control with averages of 0.74 �� 0.141 and 0.49 �� 0.104 for high and low sperm mobility phenotypes, respectively. Moreover, sequence analysis of the nucleotide fragment showed no difference between phenotypes. cPLA��� expression clearly differed between sperm mobility phenotypes. It was concluded that a difference in the regulation of cPLA��� mRNA expression contributes to variation between lines of roosters generated by selection for sperm mobility. / Graduation date: 2001

The economic literature has found difficulty linking fertility and mortality rates. Previous versions of the dynastic (parental altruism) model have failed to predict the negative relationship between fertility and infant survival, since it was postulated that parents view children as normal goods and increases in childhood survival would result in a decrease in unit-child costs. In this work, I find that a simple reformulation of the Becker-Barro altruism hypothesis successfully predicts the observed demographic transition in the past century, as well as explaining fertility differences across countries. I contest that fertility decision is dependent on the number of surviving children and not the number of children born. Child bearing is therefore perceived as risk-taking behavior given the stochastic nature of childhood survival. Essentially, higher childhood survival requires fewer children (i.e., less "hoarding") in order to ensure the desired family size. The model predicts that higher childhood survival rates will lead to a decrease in fertility. I calibrate an infinitely-lived overlapping-generations dynastic utility model and compare the fertility predictions of the baseline model with the data for the year 2000. In doing so, I have relaxed the dual normalization of the utility of death and the overall level of utility. This is necessary given that the value of children's lives are important in the parent's fertility decision. Parents jointly care for the number and utility levels of their children. I will calibrate this number and estimate this implied value of life. I find that the consumption level an agent is indifferent between life and death to be less than 1% of current consumption. I also find that parents care for their children future 47% more than that of their own. All in all, this experiment finds that fertility differences cannot be explain by differences in mortality rates alone and that incorporating human capital investment in the household production function will yield desirable results. Simply stated, lower income countries have lower opportunity costs of birthing children and will choose quantity over quality. I find that the steady state analysis of this model can explain over 62% of the cross-country variation, while mortality rates alone can explain 10%-25%. The model generally performs better for low survival, high fertility countries and vice versa. While the model tends to perform well for these economies, more needs to be done to explain fertility in the transition economies.

Thesis (M. Phil.)--University of Hong Kong, 2006. / Title proper from title frame. Also available in printed format.

Since the early 1960s, South Korea has been going through a rapid fertility decline, along with its socioeconomic development and effective family planning programs. After achieving a desired replacement level of fertility in 1984, the total fertility rate (TFR) of Korea has gradually declined to the level of lowest-low fertility. According to 2004 vital statistics, the TFR for Korea was 1.16-below the lowest-low fertility level of 1.3. Also, Korea's fertility rates have fluctuated and varied spatially, even at the level of low fertility. Undoubtedly, Korean family planning programs have been effective in population control through the last 40 years, but since 2000, the shift to pro-natal policies indicates that Korea's fertility transition is no longer a response to family planning policies. Rather, the level of socioeconomic development is still considered to have a significant effect on Korea's fertility decline. Thus, in this thesis, the primary objective is to examine the socioeconomic determinants of fertility differentials and the variation in low fertility among the counties in South Korea in 2004. Using data from the 2000 census and 2004 vital statistics, I tested the hypothesized relationships between the level of socioeconomic development and fertility based on the demographic transition theory (DTT), by estimating several Ordinary Least Square (OLS) multiple regression models. Specifically, socioeconomic predictors, such as agricultural attainment, labor force participation, and educational attainment, were primarily examined to test the validity of the DTT hypotheses. In addition, this thesis also examined the effects of women's status and traditional norms and cultural values on variation in fertility. My results showed that the DTT is applicable to an accounting of the variance in fertility rates among the Korean counties in 2004. Although the levels of fertility are extremely low all across the country, it is apparent that socioeconomic conditions are having an impact on fertility differentials in Korea.

Infertility in dairy cattle remains a major economic loss to dairy producers. Identifying dairy cattle with superior genetic potential for improved fertility would increase dairy farm profitability. Dairy heifers were classified into two groups based upon services per conception (SPC); those animals with a single SPC were determined to be highly fertile and animals with greater than or equal to 4 SPC were classified as sub-fertile. Whole genome association analysis was performed on 20 individual heifers from each group utilizing a 777K highly density (HD) single nucleotide polymorphism (SNP) chip. Genomic data were evaluated utilizing PLINK, a whole genome association analysis toolset, and 570,620 SNP were available for analysis with a total of 39 samples being analyzed. Forty-four SNP were determined to be associated with fertility classification (P <= 0.00001) and were located on Bos taurus chromosome (BTA) 2, 4, 9, 19, and 26. The SNP and ranges between SNP were analyzed using BLAST-Like Alignment Tool (BLAT); SNP were associated with 5 candidate genes for reproduction. The SNP on BTA 2 were located within the region coding for the non-imprinted Prader-Willi/Angelman syndrome 2 (NIPA2) gene, which is involved in gestational magnesium transport. Also on BTA 2, SNP were identified within the region encoding for cytoplasmic fragile X mental retardation 1 (FMR1) interaction protein 1 (CYFIP1). The CYFIP1 gene is involved with the functionality of FMR1 and has been linked to premature ovarian failure in humans. Additionally, 3 SNP on BTA 9 were located near monofunctional C1-tetrahydrofolate synthase (MTHFD1L), which has been linked to neural tube defects during gestation in humans A difference in allele frequency was observed between the two groups for SNP located on BTA19 in proximity to two genes, zinc finger 18 (ZNF18) and mitogen activated protein kinase 4 (MAP2K4). The ZNF18 motif and MAP2K4 were found to be involved in heart development of the early embryo and associated with toll-like receptors (TLR) involved in gonadotropin releasing hormone (GnRH) signaling, respectively. The involvement of one or all of these genes may further explain reduced fertility in dairy cattle.

Ejaculates from peripubertal Angus (n=106), Brahman (n=156) and Brangus (n=212) bulls were evaluated for the presence of a 31 kDa protein known as fertility associated antigen (FAA) using the ReproTest for Bulls (ReproTech, Tucson, AZ). This study was designed to test the repeatability of FAA detection using the chute-side cassette and to quantify the relationship of age, scrotal circumference, sperm motility, ejaculate volume and sperm concentration with the presence of FAA in ejaculates from peripubertal bulls. A total of 776 ejaculates were collected, and 77% (n=598) were classified as FAA+. Three ejaculates were obtained from 133 bulls (Angus, n=33; Brahman, n=100) on d 0, 30 and 60. Brahman bulls were older (p<0.0001) at puberty than Angus bulls. Ejaculate volume was the only trait that differed between bulls that were classified as FAA+ and FAA? at first collection. Mean ejaculate volume was greater (p<0.0001) for FAA? than for FAA+ ejaculates. Serial ejaculates were profiled according to one of four FAA classification patterns (0 = three FAA? ejaculates; 1 = three FAA+ ejaculates; 2 = first ejaculate FAA?; and 3 = first ejaculate FAA+). A majority of the bulls were FAA+ on all three ejaculates (57%) or at least on the first ejaculate (25%). Seven bulls (5%) were consistently FAA?, while the remaining bulls (12%) were FAA? on the first ejaculate. There were no differences in scrotal circumference or sperm concentration among FAA profiles. FAA profile-3 bulls were older (p<0.05) than FAA profile-1 bulls at 2nd collection. Sperm motility was greater (p<0.05) for FAA profile-1 than for FAA profile-3 bulls at 1st collection. Ejaculate volume was greater (p<0.05) in FAA profile-0 Angus bulls than for FAA profile-1 at 1st collection and in FAA profile-0 Brahman bulls than FAA profile-2 at 2nd collection. These data indicate that FAA classification was not affected by sperm motility, sperm concentration or scrotal circumference in peripubertal bulls. Repeatability of FAA classification was higher for bulls that were FAA+ at first ejaculation. Thus, peripubertal FAA? bulls should be re-evaluated to increase FAA-classification accuracy for identification of higher fertility as well as lower fertility animals prior to breeding.