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Globally, ~17 million women and ~2.1 million children are living with HIV. Sub-Saharan Africa accounts for 70% of HIV-infected (HIV+) persons. Mother-To-Child Transmission of HIV (MTCT) during pregnancy, delivery and breastfeeding, is the main route of HIV infection in children. The World Health Organisation recommends lifelong antiretroviral therapy (ART) for all HIV+ pregnant and breastfeeding mothers to prevent MTCT, and breastfeeding for ≥24 months for optimal child health in resource limited settings (Option B+ strategy). Initiation of ART in HIV+ adults is associated with a 2-6% decrease in areal bone mineral density (aBMD) regardless of ART regimen, but data are limited in pregnant and lactating women. Tenofovir, a preferred first-line drug in Option B+ ART regimen, is associated with 1-2% greater decreases in aBMD. Pregnancy and lactation are associated with physiological changes in maternal bone mineral density, but most evidence shows that this is recovered after cessation of breastfeeding. The hypothesis of this thesis is that ART may accentuate the normal process of bone mobilisation during pregnancy and lactation, leading to bone loss that is not recovered in the mother and/or compromised infant growth and bone mineral accretion. The primary objective of this research was to investigate if HIV+ women experience greater reductions in bone mineral compared to HIV-uninfected (HIV-) counterparts. Two groups of pregnant women, 95 HIV+ on ART (Tenofovir-Lamivudine-Efavirenz, previously ART naïve) and 96 HIV- were followed prospectively in Kampala, Uganda. Data were collected at 36 wks gestation (PG36), 2 (PP2) and 14 wks postpartum (PP14). Dual-energy x-ray absorptiometry was used to measure bone phenotype (aBMD, bone mineral content (BMC), bone area (BA), and size-adjusted BMC (SA-BMC, adjusted for height or length, weight and BA) of the whole body (WB) and lumbar spine (LS) in mother-baby pairs, and total hip (TH) in mothers. The primary outcome was the difference between groups in % change (± SE) in maternal LS aBMD between PP2 and PP14. Secondary outcomes included changes in maternal markers of bone formation (P1NP and BAP) and resorption (CTX), serum 25-hydroxy vitamin D (25(OH)D), parathyroid hormone (PTH), plasma and urine concentrations of creatinine (Cr), calcium (Ca), phosphate (PO4) and magnesium (Mg), urine mineral:creatinine ratios, TmCa/GFR and TMP/GFR, respectively), breastmilk mineral composition (Ca, P, Na, K and Na/K ratio); and infant growth Z-scores and bone mineral. Statistical models were adjusted for potential confounders. Median maternal age was 24.5 (IQR 21.1, 26.9) yrs. Mean gestation was 40.9±1.8 wks and not significantly different between groups. All women were breastfeeding at PP2 and PP14. More HIV+ women reported exclusive breastfeeding (PP2: 82.9% v 58.7%, p=0.0008; PP14: 86.7% v 66.2%, p=0.002). Body weight was 4-5% lower in HIV+ women. By PP14, mean duration of ART was 29.3±5.1 wks, adherence was > 95%, and the median CD4 count was 403 (IQR 290-528) cells/mm3. Maternal aBMD decreased between PP2 and PP14 at all skeletal sites in both groups as expected in lactation. Reductions in LS aBMD were not significantly different between groups (-1.8±0.4% vs -2.5±0.4%, p=0.3). However, HIV+ women had a significantly greater reduction in TH aBMD which persisted after adjustment for body size (-3.7±0.3% vs -2.7±0.3%, p=0.04). Median serum 25(OH)D was 67.4 nmol/L (IQR 54.8, 83.7) at PG36 and 57.6 nmol/L (48.7, 70.1) at PP14 with no significant difference between groups. Changes in 25(OH)D and PTH from PG36 to PP14 were not significantly different between groups (25(OH)D: -13.9±4.1% vs -11.1±3.1%; PTH: +60.0±6.4% vs +57.6±6.4%; both p > 0.05). However, HIV+ women had 33-35% greater plasma PTH concentrations at both PG36 and PP14. Bone formation and resorption markers increased in both groups between PG36 and PP14. HIV+ women had greater increases (CTX: +74.6±5.9% vs +56.2±5.9%; P1NP: +100.3±5.0% vs +72.6±5.0%; BAP: +67.2±3.6% vs +57.1±3.6%, all p < 0.05). They also had a greater decrease in plasma Ca (-6.6±0.5% vs-3.8±0.5%, p≤0.0001) and greater increase in plasma phosphate (+14.4±2.0% vs +7.7±2.0%, p=0.02). Changes in plasma Cr and Mg, TmP/GFR and urine mineral:creatinine ratios were not significantly different between the groups. However, at both PG36 and PP14, HIV+ had significantly lower mean plasma Ca (PG36: -1.0±0.5%; PP14: -4.1±0.6%) and TmP/GFR (PG36: -11.4±3.1%; PP14: -7.2±3.0%) but higher PTH (PG36: +33.0±7.0%; PP14: +35.3±7.6%) compared to HIV- women (all p < 0.05). Mean breastmilk Ca decreased between PP2 and PP14, and the changes were not different between the groups (-19.9±3.0% vs -24.2±3.1%, p=0.3). There were no significant changes in breastmilk phosphorus (P) in both groups, but HIV+ women had significantly higher concentrations (PP2: +9.7±3.8%, p=0.01; PP14:+9.6±3.5 %, p=0.007). Breastmilk P was significantly correlated with maternal plasma [CTX] in a separate ANCOVA model (β = +0.13±0.04% per 1% increase in CTX, p=0.0003). Mean breastmilk Na, K concentrations and Na/K decreased between PP2 and PP14 in both groups. However, HIV+ women had a smaller decrease in breastmilk Na (-44.3±8.9% vs -72.6±9.0%, p=0.03). They also had a trend towards smaller reduction in Na/K ratio (-22.2±9.3% vs -46.6.6±9.5%, p=0.07). Babies born to HIV+ mothers (HIV-exposed infants, HEI) had significantly lower gains in weight +53.0±1.4% vs +57.5±1.4%, p=0.02) compared to HIV-unexposed infants (HUI), and also lower weight-for-age (-0.47±0.16, p=0.003) and length-for-age (-0.53±0.18, p=0.005) Z-scores at PP14. HEI had a slower gain in WB BMC (+51.2±1.9% vs +57.3±1.9%, p=0.02), but the difference was not significant after adjustment for body size (-6.0±3.5% vs -7.6±3.8%, p=0.2); showing that the bone mineral accretion was appropriate for achieved infant size. In contrast, HEI had a greater increase in LS BMC (+29.5±1.7% vs +24.4±1.7%, p=0.03), a difference which remained after size-adjustment (+9.4±5.8% vs +4.3±6.2%, p=0.02). This is the first study to compare changes in maternal aBMD and bone metabolism between HIV+ mothers on Option B+ ART and HIV- counterparts. The results show a greater reduction in TH aBMD in Ugandan HIV+ women on Option-B+ ART compared to HIV- in the first three months of lactation, consistent with their greater increases in bone turnover markers, lower TmP/GFR and plasma phosphate, and higher breastmilk phosphorus concentration. Also, HEI have slower growth and whole body bone mineral accretion compared to HUI. It is important to determine if these changes are temporary or have long-term consequences for the bone health of the mother and child.

During peak lactation female mammals reach a limit in their maximal sustained energy intake (SusEI). The causes of such limits is disputed. In this thesis, I examined the causes of the limits on SusEI at peak lactation, and then explored the consequences of such limits for reproductive performance. Finally I tested a possible physiological mechanism that may underpin the trade-off between reproduction and somatic protection (the oxidative stress theory). To answer these questions, I studied reproductive performance and oxidative stress in two lines of mice previously selected for high and low food intake (MH and ML, respectively). I found that these mice reached a plateau in their food intake around day 13 of lactation. In support of the heat dissipation limits theory, reproductive performance in the MH mice was significantly higher than that of the ML mice. Oxidative damage is expected to be higher among lactating individuals. Moreover, lactating mice with greater reproductive performance are also predicted to experience more oxidative damage. By measuring multiple-markers of oxidative damage and protection in different tissues, I found that lactation resulted in reduced oxidative damage in both brain and serum. Additionally, it did not increase oxidative damage to proteins and DNA in liver. Moreover, multiple measures of oxidative stress in the mammary gland were not significantly different between mice with different reproductive effort. Furthermore, I found that lactating mice with greater reproductive performance (litter size and litter mass) had reduced protein damage in their livers and upregulated protection (HSP70) in their brains. These results were inconsistent with the oxidative stress theory. Finally, I employed a novel approach to assess oxidative stress differences with metabolomics analysis. I found that lactation resulted in significant differences in the metabolome. By focusing on the metabolites that are related to vi oxidative stress, I found that most of these metabolites measured in livers and brains were not affected by lactation which provides more evidence against the oxidative stress theory. My results provide support for the heat dissipation theory as a mechanism explaining the limits on reproductive performance. Moreover it provides comprehensive information against oxidative stress as a mediator of life history trade-offs.

In the 2019-2020 school year, there are at least 30,000 pregnant students on U.S. university campuses who might need a place to pump or nurse while in school. National policies protect the need for time and space for employed lactators, but there are only suggested protections for space for lactating college students. Many postpartum people, members of the campus community, are falling through the gaps of support by their universities. Some universities have developed policies that require lactation rooms for capital construction projects. The state of the policies themselves and consistency of the application in the built space is poorly understood. Few policies address the larger issue of inclusion for this diverse population. This study investigated the issue of lactation rooms on campuses from three different perspectives or domains of knowledge. The work explored the claims made by universities about postpartum support and lactator inclusion (proclamations); the manifestation of those policies in the lactation space (actions); and the user experiences of lactating on their campus (perceptions). The perspectives provide contrasting views on the adequacy of lactation space in this complex ecosystem and the needs for improving the process of developing new policies, the application in capital construction, and the operation of lactation rooms. Merging the socio-ecological model with the human rights model (Availability, Accessibility, Acceptability, and Quality (AAAQ)), lactation policies on two case study campuses were assessed to evaluate the claims made by universities about inclusion and dignity as represented in the built environment. Using a mixed-methods approach of institutional ethnography, an environmental assessment (merging photovoice and indoor comfort measurements), and narrative interviews with lactators, the study centred the lactation room as a site of place-making to demonstrate the overall impact of the interrelationships and intersection of these three domains of knowledge. The results indicated that design and construction standards on the case study campus have changed over time in response to national policies and other influences. The findings illuminate that the facilities themselves have not changed to meet the contemporary needs of lactating bodies of varied academic intersectionalities. Despite policies focused on improving spaces for lactating people, best practice guidelines for lactation rooms, and many publications describing the barriers that users experience in meeting this basic need, universities are still struggling to include all of the lactating people in developing their physical infrastructure and to create the supporting social infrastructure. To address some of the gaps in the immediate future, universities could include the variety of lactating people when creating web-based messaging for lactation room access. Future needs include developing postpartum provisions for the lactators and clearly communicating what is available to them. Universities should develop additional sessions on postpartum support to include in their diversity, equity, and inclusion (DEI) trainings for supervisors. The dramatic change in abortion policies in the U.S. directly impacts this age population. Therefore, student health tracking systems need to incorporate more questions on birth experiences, postpartum needs, and lactation. Universities are unique ecosystems and the current desire to improve in policy and action. There is now an incredible opportunity to explore multi-tiered approaches to improving the DEI landscape.

Many benefits to breastfeeding exist for both mothers and infants, yet exclusive breastfeeding rates remain low across the nation. These benefits include decreased chance of infections for infants, low infant mortality, and decreased chances of breast and ovarian cancers for mothers (Binns et al., 2016; CDC, 2023). Education strategies have recently become imperative for health organizations to help mothers sustain their ability to breastfeed within the recommended six-month timeframe. Current literature on education supports that women who receive education at some point in their lactation journey are more likely to reach the six-month period and have more confidence in their ability to provide for their infant (Alianmoghaddam et al., 2018; Silva et al., 2016; Tseng et al., 2020). Occupational therapists are experts in role promotion and addressing routines to make them more effective. Therefore, occupational therapists may have a role in breastfeeding promotion to help women reach their occupational goals of breastfeeding and improve health outcomes for mothers and infants on a population level (Pitonyak, 2014; Visser et al., 2016). To demonstrate the need for occupational therapists in the field of lactation, a five-week postpartum breastfeeding course was developed to be implemented in the community. One participant attended all five sessions and completed a pre- and post-survey. Results from the COPM demonstrated an improved sense of importance (pre-average: 6.4, post-average: 8.3) and satisfaction (pre-average: 4.4, post-average: 6.4) in breastfeeding-related occupational performance. The BSES-S also demonstrated a self-reported improved sense of self-efficacy regarding breastfeeding (pre: 49, post: 55). Limitations of the study included a higher level of one-on-one support than the program intended and the lack of diversity in participant experience.

This study investigated the hypothesis that the particulate content of milk, as monitored with particle counters, is correlated to the health status of lactating dairy cows, in particular the condition mastitis. Twenty Holstein cows were monitored from the very first day of clinical mastitis outbreak until complete recovery from the disease. During the experiment, the changes in particle behaviour in all four quarters and mixture of milk from all of them were measured. For each sample the following parameters were measured: somatic cell count, fat content, lactose and protein concentration, number and size distribution of milk particles, electric conductivity and diameter of milk fat globules. In total over thirty mastitis outbreaks were observed and monitored throughout, including the first phase of this study when over three thousand samples of foremilk were collected and examined. An operational protocol and particle monitoring device were designed with the help of a commercial company Facility Monitoring Systems Ltd (FMS), Malvern. A particle counter and Peak Height Analyser (PHA) were used to monitor particulate content of milk and a compound phase contrast microscope was used to identify milk particles by photographic visualisation and to establish their diameter. It was observed that the number of particles, milk fat globule diameter and somatic cell counts were stable during periods without udder inflammation. Mastitis caused great changes in these parameters. Both milk particulate size and number were significantly affected by clinical and subclinical form of inflammation (change to the particulate behaviour). It was observed that the changes to the volume median diameter (VMD) of fat globules became evident a few days before clinical signs were present. Results obtained from a particle counter and the PHA were in agreement with data obtained by microscopy. Major changes were recorded in the number of total particles in milk before and during the outbreak of mastitis. Further research showed that changes took place in the pattern of particulate behaviour without visible signs of disease; additional data established that subclinical mastitis can be also identified through the monitoring of particles in milk. In summary monitoring of the behaviour (changes to size and number) of milk fag globules (MFG) can be used as an early indicator of the onset of mastitis. In addition data collected during study produced strong evidence supporting the theory of the interdependence of the quarters within the udder. It was found that the coefficient of correlation for size and number of particles for all four quarters within the udder was statistically significant. Particle counts and the VMD values behaviour were similar for the four quarters. This relationship was observed for all monitored animals. Moreover, the same relationship was also observed during both clinical and subclinical outbreaks of mastitis. Somatic cell count was affected only in an infected quarter while particulate content of milk ―responded‖ to disease in all four quarters within the udder (even if only one was infected). These results were the most surprising and unexpected outcome, suggesting that four quarters within the udder work together as one organ not four separate units. It was observed that the mean MFG cannot be used as a baseline to test individual animal deviations due to the unique particle profile of each observed animal. In all monitored animals particle counts obtained from PHA was found to be in the range of 1011 to 1013 with an average of 1012 particles per ml. The number of particles recorded in mastitis for one animal was at the healthy level for another. The particle pattern became a finger print for each animal and therefore MFG behaviour cannot be compared between animals. Following the first phase of the study the monitoring period was set at 15 to 20 days. This protocol allowed for minimising the influence of any other parameters on particles, which may influence the outcome of an experiment e.g. the number of particles in single samples detected by the particle counter. It was also essential to understand how the age, nutrition and stage of lactation might influence the particles and affect the results. Therefore two animals were chosen to be examined during their lactation. The analysed data did not present enough evidence to establish the relationship between nutrition and milk fat globules size and number. However to better understand this association additional studies should be carried out. Further work is required to optimise the monitoring device and build a fully automated system which will allow collecting and analysing data from the whole herd. This study proposed that particle pattern is unique for each animal – like a finger print. More research is needed to better understand the mechanism behind milk fat globules synthesis during inflammation. The results obtained during this study provide new evidence with regard to physiological changes within the udder before and during mastitis outbreak and supported the theory of interdependence between quarters within udder. The particle count in milk can be used as an indicator of the health status of the single animal. Combined the PHA and microscope can be used as a new tool to determine and monitor the particle count in milk. The understanding of the particulate behaviour will help to minimise the chance of mastitis outbreak by early detection and also to reduce the chance of the cross-contamination between animals during the milking process. Milk fat globule size and number can be used as an efficient indicator of the onset of mastitis.

Mammals usually develop immunity to gastrointestinal nematode parasites. However, during late pregnancy and lactation, this immunity often breaks down, resulting in elevated levels of parasitism. This periparturient relaxation of immunity (PPRI) renders lactating hosts main sources of infection for their parasite-naïve offspring, and may have a nutritional basis. Results of studies on parasitized hosts suggest that both crude protein (CP) and metabolizable energy (ME) supply may be important in regulating the degree of PPRI by affecting the immune response towards parasites. However there is a scarcity of data supporting such a role for ME in periparturient hosts, while there is sufficient evidence to support the view that CP in general, and amino acids are potent immunonutrients in various disease states (Chapter 1). In the first experiment (Chapter 2) I seperated effects of CP and ME on PPRI by feeding parasitized lactating rats at two levels of ME supply and one of three levels of CP supply. The results show that PPRI is sensitive to CP scarcity, and not to moderate ME scarcity. Increasing CP supply improved lactational performance and reduced PPRI, as observed by reduced worm burdens. In the second experiment (Chapter 3) I examined the rate at which improved nutrition can restore immunity by feeding low protein diets to rats nursing high number of pups, and then reduced litter size in a sub-group so that host nutritional status would change from scarce to adequate. The egg production of the parasite population of the latter group reduced within days to similarly low levels as rats that had always reared low number of pups and this was associated with an increased number of musosal mast cells and increased dam weight gain. Since host responses to dietary CP are almost by ii definition responses to essential amino acids, the third experiment assessed the sensitivity of PPRI to methionine and leucine deficiency (Chapter 4). The latter resulted in increased worm burdens and egg production to similar levels when low protein diets are fed and imposed penalties in lactational performance. Finally, in the fourth experiment it was investigated whether similar outcomes can be expected in periparturient ruminant hosts by supplementing sheep with field beans, which are deficient in methionine, instead of soybean meal (Chapter 5). Indeed, feeding high protein diets based on field beans was less effective in reducing the worm egg excretion and improving lactational performance. The data from this thesis (Chapter 6) provide novel information on the nutritional basis of PPRI, showing that the latter can be rapidly reduced through improved protein nutrition. This may be seen as a response to the protein quality of the diet and the supply of amino acids in optimum quantities. These results have implications for parasite control strategies in farm animals.

A methodology for ageing foetal and neonatal cattle is developed, involving radiographic examination of infant mandibles for early developmental stages in molariform teeth; tooth-wear methodologies are imprecise at this stage before wear commences. Known-age modern bovine foetal and neonate material are collected as a control assemblage for method development (n=73); six Neolithic to Norse era assemblages from Orkney are examined using the modified technique together with standard tooth-wear analysis and other methodologies. Foetal and died-at-birth material is diagnosed at most sites using the new technique, together with a range of other peri-natal age-groups. Ageing at this early stage is highly relevant in the diagnosis of milking as a palaeoeconomy: the accepted view is that unwanted (male) calves were slaughtered to maximise milk for human consumption, hence a surfeit of neonate calf remains, as at the study sites. The diagnosis of foetal and died-at-birth material challenges this view, suggesting that attritional causes may have contributed to deaths at this stage. Although milking was probably carried out at most of the study sites, this may have been combined with slaughter of cattle for meat in a pragmatic exploitation strategy. Literary research shows possible attritional causes of abortion and early death in calves, in particular dietary insufficiency in pregnant cows, microbial infections, and also inadequate colostrum uptake. Additionally, research is used to consider the challenges to health that early milking might have posed, to the calf as mentioned, but also to the cow, where three main health issues are highlighted: infertility, mastitis and lameness.

In this investigation energy demands from offspring were varied for the MF1 mouse after litter sizes were manipulated and set to 5 pups/litter or 16 pups/litter by cross-fostering to examine the effects on immediate lactation and subsequent reproductive performance. Pups reared in manipulated large litters grew slower and were weaned lighter (half the size of pups reared in small litters) than pups reared in manipulated small litters.  Mortality of pups was high in the large litters but pups did not die in small litters. The results of a subsequent reproduction that followed the first lactation suggested an apparent cost for the female group that previously reared pups in large litters.  This is because in the subsequent reproduction, the group raised litters that were significantly (P<0.05) 12.7g less in mass than litters raised by females that previously reared pups in small litters.  This apparent cost, however, did not appear to have severe negative impact on the general reproductive performance because data showed comparable litter sizes and masses at birth, growth rates of pups, and the number and masses of pups weaned between this group and females that previously reared pups in small litters. At reproductive age, female offspring previously weaned from large litters weighted significantly (P<0.05) 5.8g less than female offspring previously weaned from small litters.  During their first breeding attempt or episode, female offspring previously weaned from large litters did not catch-up in body mass with those previously weaned from small litters.  In spite of this, the two groups ingested similar quantities of food prior to mating and during lactation.  The groups did not differ significantly (P>0.05) in efficiencies of energy utilization, milk energy output and daily energy expenditure.  Consequently, they showed comparable breeding success. Different age groups of male and female offspring previously weaned from manipulated small (5 pups/litter) or large litters (16 pups/litter) and unmanipulated normal litters (10 pups/litter) varied significantly in body mass and did not show compensatory growth at the time they were examined for susceptibility to obesity and glucose intolerance.  A batch of six months old male offspring previously weaned from litters whose mothers were fed a particular macronutrient diet during lactation did not differ significantly in body mass when they were also examined for susceptibility to obesity.  All groups and sexes showed a tendency to develop obesity when they were challenged with a diet that contained up to 45% fat by calories.  Development of obesity did not appear to depend on  a particular litter size in which the mice were previously reared and weaned or whether the mice were previously suckled by mothers that were fed a particular macronutrient diet.  However, the development of obesity exhibited sexual dimorphism with the male offspring showing a higher tendency to develop obesity than female offspring.

Limits to sustained energy intake during lactation were investigated in MF1 mice.  The feeding of high protein to females at 21°C had negative effects on lactation performance.  This was because the females consumed much less food and energy at peak lactation but their mean daily energy expenditure (DEE) was higher than that of females fed  high carbohydrate diet, so the energy available for milk production was greatly reduced. The feeding of high and medium fat diets to lactating females at 21°C had positive effects on lactation performance.  The females consumed much more food and energy at peak lactation but their mean DEE was the same as that of females fed low fat, so the energy available for milk production was greatly increased.  The positive effects of feeding high and medium fat to the lactating mice were far greater than predicted by the heat dissipation limit hypothesis, suggesting that this hypothesis can not explain all the findings of the present study.  The fixed DEE of  high fat, medium fat and low fat fed females strongly support the heat dissipation limit hypothesis. Lactation significantly decreased pro-opiomelanocortin (POMC) and increased agouti-related peptide (AgRP) gene expression in the hypothalamic arcuate nucleus (ARC) despite the reduced neuropeptide Y (NPY) expression in the ARC.  Activated AgRP orexigenic pathways and attenuated anorexigenic POMC pathways in the hypothalamus probably promoted the hyperplagia of lactation.  The fact that AgRP increased while POMC decreased but SOCS-3 was unchanged in the lactating females exposed to 21°C indicates that the MF1 mice were sensitive to the action of leptin.  mTOR was not involved in lactation hyperphagia in MF1 mice.  Lactation significantly increased fat mass and obesity-associated gene (FTO) expression in the hypothalamic ventromedial nucleus.  There were no changes in the main anabolic and catabolic neuropeptides at 30°C.

Abstract: Background: Vitamin A status is an important health determinant. Deficiency of this micronutrient is a serious global health issue in the developing nations as the leading cause of preventable blindness in children and is a significant contributor to long-term morbidity and mortality. Nutritional demands for vitamin A are highest during pregnancy and lactation. This period is important for establishing offspring’s vitamin A reserves critical for long-term health. Aim: Our overall objective was to better understand the mechanisms underlying the delivery of vitamin A to maternal milk and offspring in mice. This included an analysis of: 1) maternal vitamin A homeostasis during lactation, with a focus on the mammary gland, and 2) genetic, and 3) dietary intervention studies designed to dissect the contribution of maternal vitamin A stores and dietary vitamin A intake in the establishment of vitamin A reserves in offspring. Methods: All studies were conducted in mice. In Chapter 3, the mammary gland and other tissues were collected from virgin, lactating and involuting mice, followed by an assessment of gene expression (qPCR) and tissue vitamin A concentrations (HPLC). In Chapter 4, wild-type pregnant mice were split into two groups, one receiving a diet with 25 IU vitamin A/g, and one receiving a vitamin A deficient diet (0 IU vitamin A/g), during pregnancy and lactation. Tissues were collected from offspring at (postnatal day [P]1), during lactation (P7), at weaning (P21), two weeks post-weaning (P35), P70 and P105 with vitamin A concentrations measured by HPLC. In Chapter 5, tissues were collected from the offspring of wild-type and Lrat-/- female mice at P1, P7 and P21 vitamin A concentrations were measured (HPLC). Results: In Chapter 3 we observed a shift in the expression pattern of the vitamin A metabolic pathway in the mammary gland of lactating mice. Most prominently, there was a significant increase in the expression of the retinyl ester-synthesizing enzyme Lrat during lactation, which returned to baseline following involution. In Chapter 4, our results show a direct relationship between maternal vitamin A intake and offspring liver retinol and retinyl ester reserves. Offspring from dams consuming a vitamin A deficient diet had consistently lower hepatic vitamin A levels than control at P7, P21, and P35, which returned to control group concentrations at P70 (adulthood). In Chapter 5, we observed no significant differences in the hepatic vitamin A status of heterozygous offspring born to wild-type and Lrat-/- female, despite Lrat-/- female lacking hepatic vitamin A stores. Conclusion: We have characterized pronounced changes in the vitamin A metabolic pathway in the mammary gland of lactating mice, consistent with the role of LRAT as the primary enzyme responsible for retinyl ester incorporation into milk. Our study further supports the hypothesis that maternal dietary vitamin A intake is critical in establishing adequate vitamin A reserves in offspring and suggests that maternal hepatic stores cannot compensate for a lack of maternal dietary vitamin A. Moreover, vitamin A sufficient pups accumulate hepatic vitamin A stores with time, which is hindered in pups with dams on a vitamin A deficient diet and persists until early adulthood despite the introduction of adequate dietary intake after weaning.

1. The studies presented in this thesis investigated some metabolic actions of beta-casomorphins in dairy cows. Three beta-casomorphins (beta-casomorphin-4-amide, -5 and -7) were used. Investigations of the actions of the beta-casomorphins in dairy cows require gram quantities of each peptide. This was achieved by synthesising the peptides using solid phase peptide synthesis combined with FMOC chemistry. 2. The first experiment examined possible stimulatory actions of the peptides on amino acid uptake by the mammary gland using explants of lactating rat mammary glands as a model in vitro system. There was no evidence of their actions on amino acid uptake by the mammary gland as judged by the lack of their effects on the uptakes of four amino acids (glutamate, histidine, leucine and lysine). Because of the inability to demonstrate effects of the peptides at the mammary gland level, it was decided to focus on their effects at the level of the gut. 3. As a first step, the extent of ruminal degradation of the beta-casomorphins was determined in incubations in rumen liquor in vitro. All three peptides were degraded rapidly with half-lives of only 15 to 20 minutes. In a subsequent experiment, an attempt was made to chemically protect the peptides from the ruminal degradation using N-terminal acetylation. The half-lives of the N-acetyl beta-casomorphins were markedly increased to 6 1/2, 7 1/2 and 4 hours for beta-casomorphin-4-amide, -5 and -7 respectively. However, it was recognised that, whilst the method would be a simple and effective method for the protection of the peptides, further developments of the method would be necessary to ensure their release in active form at their sites of their action in vivo. 4. In experiments on the actions of the beta-casomorphins in vivo, the peptides were infused direct into the abomasum. The first experiment compared hormonal responses to the abomasal infusion of sodium caseinate, a potential source of beta-casomorphins, and an acid hydrolysate of casein, which was not a potential source of beta-casomorphins. There were clear suggestions of differences in responses of some hormones, notably insulin and GIP. In the second experiment, effects of abomasal infiisions of mixtures of the ?- casomorphins themselves at three different dose levels on changes in concentrations of the hormones were investigated in lactating dairy cows. There was no clear effect of the beta-casomorphin infusions on insulin concentrations except for some tendency towards inhibition at some time points. However, the incremental response of glucagon to the beta-casomorphin infusions was linearly increased (P < 0.05) leading to statistically significant decreases in the insulin / glucagon ratio at 4 hours by all beta-casomorphin infusions compared with control. 5. In the final section of the thesis, attention was focused on the possible inhibitory effects of the beta-casomorphins on insulin secretion. Three experiments were carried out. Experiment 1 was designed to detect the inhibitory action of the beta-casomorphins on the insulin level prestimulated by an abomasal infusion of glucose. The insulin concentration rise was significantly inhibited by the beta-casomorphins (P < 0.05). The inhibitory action of beta-casomorphin was shown to be compatible with the action of SS- 28 as judged from the effects of SS-28 on the insulin secretion when administered intravenously in the same experiment. However, the inhibitory action was not evident in the next experiment in which lactating animals were used, probably because of differences in the sensitivity of insulin secretion in lactating versus non-lactating animals. The final experiment confirmed the insulinopenic effect of the ?- casomorphins by demonstrating their inhibitory action on the insulin concentrations prestimulated by an intravenous infusion of glucose. 6. Taken together, the results of the experiments described show effects of beta-casomorphin infusions on circulating levels of hormones in the ruminant. The most pronounced effect was the modulation of the insulin response to abomasal or intravenous administration of glucose.

This thesis examines the importance of mammary apoptosis during lactation and involution and investigates some of the factors which influence apoptotic rates in the mammary gland. The extent of apoptosis in mammary tissue was assessed using (32P)dCTP nick-end labelled DNA to visualise DNA laddering. Changes in DNA laddering were compared with histological techniques to determine general tissue morphology, chromatin changes and presence of apoptotic bodies and localisation of dying cells (ISEL). Where possible these measurements were combined with gene expression studies to determine changes in expression of proteases, inhibitors of proteases, p53 and bax. As shown previously, apoptosis is important for cell removal in rodents during natural weaning and after litter removal at peak lactation. In both situations apoptosis followed a similar time course, however, after litter removal in declining lactation the increase in apoptosis was more rapid. Apoptosis also appeared to be essential between lactation cycles even when the interval between lactation cycles was reduced to a minimum by mating at post partum oestrus. DNA laddering was detected at peak lactation of mice, rats and goats, suggesting that cell turnover is a physiological process in lactating tissue. This study also investigated the regulation of mammary apoptosis. The effects of hormonal status of lactating rats and milk stasis in mice and goats were investigated. Prolactin, acting as a cell survival factor, was shown to influence apoptosis. Growth hormone action was more subtle, and was achieved through a different mechanism to that of prolactin. A local mechanism for regulating mammary apoptosis was demonstrated in mice where unilateral milk stasis induced apoptosis at levels similar to litter removal. Apoptosis was also induced in goats by a local control mechanism since unilateral cessation of milking increased apoptosis to a greater degree in unmilked glands compared to milked glands. Finally, possible mechanisms of local and systemic control were studied during lumen formation when mammary cells were cultured on extracellular matrix, in vitro. After several days on extracellular matrix solid clumps of epithelial cells form hollow spherical structures. Cells on the periphery of the cell clump survive, and only these have access to laminin, (a component of the extracellular matrix). Cells in the centre of the clumps die by apoptosis, and this produces luminal spaces within the structures. An IGFBP is also elevated at the time of apoptotic cell removal, and may be involved in blocking IGF-1 activity in cells that are to die. In conclusion, this study demonstrates the widespread importance of apoptosis in the mammary gland, the local and systemic regulation of the process and some clues as to the mechanism of apoptosis in mammary cells.

Pregnancy serves as a significant motivating factor for many pregnant people to reduce or abstain from substance use. However, many women relapse during the postpartum period. Additionally, in the United States, substance-use related deaths are a leading cause of maternal mortality. One potential targeted intervention is development of a lactation support program designed for patients with a history of substance use. Providing supported lactation services to this higher risk population may extend abstinence motivation from pregnancy to the postpartum period, reducing postpartum relapse rates and improving lactation rates. In addition to increasing contact during the postpartum period, targeted breastfeeding support may deter against substance use during an emotionally challenging period fraught with relapse triggers. The quality improvement project aim is to increase support for vulnerable patients through a pilot lactation program. The project lead evaluates the effectiveness of the pilot to impact breastfeeding rates, postpartum substance use, and maternal satisfaction. By pairing patients with a Certified Nurse-Midwife Internationally Board-Certified Lactation Consultant who focuses on patients with a history of substance use, obstetric practices may impact rates of breastfeeding and postpartum substance use while also achieving high levels of maternal satisfaction. Few studies focus on the unique needs of people with a history of substance use. As rates of substance use increase in the United States, focused research is needed to determine how to best support this population.

This qualitative research study is the first in education to explore the daily, visceral experiences of K-12 lactating teachers in the United States. Across disciplines, scant research has been conducted that focuses on the embodied and emotional experiences of lactating people at work (Gatrell, 2019; Ryan, et al, 2011; Stearns, 1999). Bodyfeeding is a marker of “good” citizenship and “good” parenting, yet teachers, charged with reproducing state ideologies of citizenship, don’t have the space or time needed to express milk at work. This research fills a gap in cross-disciplinary literature focused on remedying the ways capitalist, patriarchal institutional structures sidestep the bodily needs of workers for the sake of workplace efficiency. It shows how lactating teachers navigate and make sense of two conflicting imperatives: On the one hand, the engrained ways they have learned to orient their time towards the reproduction of schooling norms, and on the other, their embodied need to produce milk. Informed by feminist approaches to qualitative research, I conducted 20 in-depth qualitative interviews with teachers in the Twin Cities metro who have expressed milk at work since 2010, and another 15 interviews with union leaders, administrators, and public health officials across Minnesota. I frame my study using social reproduction theory (Bhattacharya, 2017; Federici, 2014) to show how reproductive labor like expressing milk is framed as “not-work” within a capitalist understanding of production. I use poetic transcription to foreground the firsthand accounts of teachers and to demonstrate the embodied and emotional resonances across participants’ accounts (Cahnmann-Taylor & Siegesmund, 2018; Faulkner, 2016). For data analysis, I take up cultural historical activity theory (Engeström, 2001) to argue that the need to express milk functions as a crucial moment because teachers cannot fulfill their role as professionals as mapped out by current expectations. I take up Garland-Thomson’s (2011) concept of misfits and Sarah Ahmed’s (2017) subsequent application of this concept to show how the onus is put on lactating teachers to navigate incompatibilities between their bodily needs and the school day regime and positions them as “misfits” in schools. I draw from the concepts of outlaw emotions (Jagger, 1989), pleasure activism (brown, 2019), and the uses of the erotic (Lorde, 1984) to highlight the how the emotional experiences of lactating teachers need to be considered when creating policies and practices about lactation. Findings illustrate how patriarchal, capitalist logic is at play in how time and space are organized in schools, and how lactating teachers’ bodies are positioned by this logic, while they also resist and transform the organization of schools. My study shows that a lack of structural support for lactating teachers contributes to an inequitable work environment in schools. Implications include that individuals, buildings, and districts can create more humane conditions for lactating teachers by enacting modest reforms like creating school lactation spaces and providing additional time, outside of existing break times, to pump. Yet while stop-gap reforms in schools such as creating lactation spaces are one step in the right direction, more sweeping change is necessary.

Increased milking frequency (IMF) in early lactation is a time and cost-effective farm management practice to enhance profit in the dairy industry. The process involves milking cows more often in early lactation alone. On farms that milk twice daily (2X), early lactation cows are milked four times daily (4X) for 21 d postpartum. Cows produce significantly more milk during this timeframe and continue to have increased milk yield (MY) when returned to 2X milking for the remainder of lactation. The objective of this dissertation was to discover the physiological processes of early lactation IMF that cause increased MY throughout lactation. All studies involved unilateral frequent milking (UFM) with 2X and 4X udder halves for 21 d in early lactation. The first study manipulated milking interval (MI), or the time between milkings, during early lactation IMF. Cows were either milked on an even MI every 6 h or unevenly on a 9:3:9:3 h MI. Unevenly milked cows produced more milk on the final day of 4X treatment, but there was no significant difference in the increased MY carry-over effect between MI groups. Therefore, farmers can utilize any MI that fits their schedule and still achieve significantly enhanced profits. The second study aimed to infer the metabolic mechanisms of early lactation IMF that increase MY by comparing it to bovine somatotropin (bST). Cows that underwent early lactation IMF received bST at 80 DIM. Both IMF and bST treatments significantly enhanced MY, but there was no interaction or synergistic effect between treatments. We surmised that IMF and bST cause increased MY through different metabolic mechanisms since IMF functions locally and bST operates systemically. The final study analyzed mammary tissue from 2X and 4X udder halves on the final day of UFM treatment. The mechanism in which IMF enhanced MY involved increased protein levels of signal transducer and activator of transcription (STAT5), activated and total protein kinase B (Akt), and total extracellular signal-regulated kinase 1 and 2 (ERK1/2) and reduced protein levels of total mammalian target of rapamycin (mTOR) and total mitogen activated protein kinase (MAPK) in 4X udder halves compared to 2X.

The most common reason for premature breastfeeding cessation is real, or perceived, low milk supply. Maternal stress suppresses milk production, but the mechanism by which stress inhibits lactation has not been defined. The mammalian stress response is mediated in large part by glucocorticoids (GC). It is well-established that excessive endogenous and exogenous GCs transiently suppress milk volume and milk lactose content, without affecting milk fat or protein levels. In vitro studies from the 1980s suggested that the biphasic regulation of alpha-lactalbumin (LALBA) synthesis by GCs is central to the pathophysiology of stress-induced suppression of milk lactose content and milk yield. The LALBA protein is unique to the mammary gland and is required for lactose synthesis and milk production, yet its transcriptional regulation has yet to be defined.We first sought to define the effect of a synthetic GC (dexamethasone, DEX) on milk yield and composition alongside changes in mammary gene expression in dairy cows. We demonstrated that a single, high dose of DEX administered to lactating dairy cows transiently suppressed milk volume, milk lactose content, milk LALBA content, and LALBA gene expression. Then, we wanted to determine the reliability and replicability of the murine mammary explant system for the study of GC-mediated regulation of Lalba expression. We defined doses of corticosterone (CORT) and DEX and time intervals at which Lalba expression could be maximally upregulated, inhibited, or suppressed following initial stimulation. We demonstrated for the first time that Lalba expression in mammary explants from midpregnant mice can be suppressed by over 50% in response to high dose of CORT after initial 48 h of stimulation by a low dose of CORT. The extent to which a decrease in LALBA gene and protein expression contributes to the decline in milk lactose content and milk yield remains to be determined. Future research endeavors should focus on defining the GC-regulated transcriptional landscape at the Lalba promoter using the murine mammary explant system. Determining the mechanism by which GCs modulate LALBA transcription will inform preventative and therapeutic strategies for low milk supply and improve maternal-child health outcomes.

Mammals are defined by a unique tissue, the mammary glands, which secrete milk that feed their offspring. Even though a milk supply is vital to species’ survival, the molecular mechanisms that regulate lactation remain obscure. Recent research shows that acquiring nutrients from mother’s milk confers a lifetime of benefits, yet many women around the world are unable to produce sufficient milk to supply the needs of their infant. Establishing therapeutically targetable molecules that drive lactation promises to help women experiencing lactation insufficiency syndrome and expand the health of the population. In my thesis work, I show that the protein Van Gogh-like 2 (VANGL2) plays a novel role in the nucleus where it inhibits differentiation of mammary epithelial cells into milk producing alveolar cells. My data show that VANGL2, working in conjunction with the polycomb repressor protein BMI1, represses the transcription of pro-differentiation genes. Decreasing the nuclear localization of VANGL2 results in precocious differentiation and more milk. This research presents a novel role for VANGL2 in regulating gene transcription at a crucial point in tissue differentiation, making it an appealing clinical target for lactation insufficiency.

Lactation and breastfeeding support the short- and long-term health of both mother and infant, yet the success of these processes depend upon both individual and shared factors. Complications during pregnancy and delivery negatively affect the likelihood that a mother will be capable of breastfeeding for at least the first six months of life, as recommended by the American Academy of Pediatrics (1). Guidelines for women regarding postpartum diet and lifestyle management also fail to reflect the diversity of mother-infant pairs and their circumstances. In our analysis of the literature, we have identified a categorical deficit in modern scientific discourse regarding human lactation; namely, that postpartum involves full-body contribution of resources and thus requires the application of nutrition from a systemic perspective. These observations, combined with recent research indicating that the vitamin B3 derivative nicotinamide riboside may improve lactation success while conferring additional long-lasting benefits to the dyad, inspired a randomized-control clinical trial consisting of a small cohort of female participants who have given birth prematurely. As a consequence of the COVID-19 pandemic, recruitment for the described study has been approved by the UC Davis institutional review board but not yet begun at the time of publication. The primary aim is to determine whether supplementation with nicotinamide riboside during the immediate postpartum period has a measurable effect on milk production (i.e. its ability to act as a galactagogue). Secondary outcomes are intended to direct future hypotheses regarding the mechanistic action of this compound (i.e. its ability to act as a metabolic regulator). This contribution to the field of lactation research is significant in that it prioritizes interventions at the beginning of life that demonstrate the potential for measurable improvement in long-term health.

The effects of alterations in endocrine and nutritional state on lipogenesis in vivo in mammary gland, liver, white and brown adipose tissue (WAT,BAT) of the lactating rat were investigated. During lactation, lipogenesis was increased in liver, decreased in BAT and unchanged or decreased in WAT; the mammary gland was the major site of lipogenesis. Insulin administration did not increase lipogenesis in the gland any further but it increased it in liver, WAT and BAT. Removal of the pups or suppression of prolactin secretion increased the plasma insulin concentration and lipogenesis in liver, WAT and BAT. There may be a reciprocal relationship between plasma prolactin and insulin, and the hypoinsulinaemia of lactation may be important in restricting lipogenesis in liver, WAT and BAT to promote the direction of glucose to the gland. An oral load of glucose increased lipogenesis in vivo 2-fold in liver of virgin and lactating rats and 8-10- fold in BAT of virgin rats but had no effect on BAT of lactating rats. BAT slices from lactating rats showed decreased rates of lipogenesis in vitro. An oral load of medium- or long-chain triacylglycerol inhibited lipogenesis in mammary gland in vivo (82-89%) This inhibition was reversed when the acini were incubated in vitro. Insulin administration reversed partially the inhibition of lipogenesis in vivo. Long-chain triacylglycerol inhibited hepatic lipogenesis in vivo but medium-chain triacylglycerol increased it 2-fold. Lactating rats fed a high-energy diet had a decreased rate of mammary gland lipogenesis in vivo (60-80%). Glucose uptake and lipogenesis by the isolated acini in vitro correlated with the depressed lipogenesis in vivo. Insulin in vitro reversed glucose uptake and lipogenesis to values approaching those of controls fed on chow diet. In lactating rats the high-energy diet did not affect hepatic and WAT lipogenesis but it increased BAT lipogenesis. In virgin rats the high-energy diet increased WAT lipogenesis but it decreased hepatic and BAT lipogenesis. It is concluded that in lactating rats the highenergy diet results in a decrease in sensitivity of the mammary gland to insulin and in increased partitioning of carbohydrate to BAT while in virgin rats excess carbohydrate is partitioned to lipogenesis in WAT.

Human milk sharing (HMS) is a poorly understood, emergent infant-feeding practice involving the commerce-free exchange of expressed human milk (HM). In this dissertation, we took an exploratory mixed-methods approach to investigate HMS experiences, practices, and risk perspectives among milk-sharing parents. Ethnographic interviews were conducted with 30 HMS recipients in Washington, DC. Interviews were recorded, transcribed, and iteratively analyzed using an inductive approach to identify and analyze emergent themes. These data were used to inform the development of a quantitative online survey of milk-sharing practices that was distributed to 168 HMS participants (98 recipients, 70 donors) in Washington, DC. Descriptive analyses were used to summarize the data by donor/recipient status. Latent profile analysis (LPA) was used to identify discrete risk perspectives among donors and recipients. Our survey results demonstrated that HMS participants achieved a high duration of lactation and HM-feeding and recipients engaged in a wide variety of risk-mitigation practices. While sociodemographically similar, donors and recipients differed substantially in their maternal experiences and infant-feeding practices. The LPA detected heterogeneity in risk perspectives among HMS participants, which underscored the complexity of infant feeding risk constructions. The LPA results confirmed that HMS risk is interpreted relative to infant-formula risk. Beliefs about infant formula and the importance of donor familiarity emerged as important constructs in parents’ risk perspectives. Our qualitative study demonstrated that the experience of HMS recipients is often a product of infant-feeding challenges that evoke feelings of guilt and shame. Emergent themes about recipient decision-making revealed careful and thoughtful analysis of infant-feeding options. Trust of breastfeeding mothers, a high value placed on human milk, and mistrust of infant formula played key roles in the decision to milk share. These findings highlight important features of the milk-sharing experience and emphasize the need for evidence-based, non-judgmental support for families who experience breastfeeding challenges or seek alternative infant-feeding options. Better understanding of the risk perspectives held by HMS participants is critical for elucidating parental decision-making processes and developing more targeted approaches to patient care and messaging about infant feeding.

One potential approach to control GIN parasite and to improve ewe’s immunity during the periparturient period is nutritional supplementation. However, there is limited data regarding the long-term effects of nutritional supplementation on grazing periparturient ewes that have a naturally acquired GIN infection where two or more parasite species are infecting ewes and lambs. This thesis describes a series of experiments designed to analyse the effects of targeted supplementation to twin-bearing ewes on pasture and determine whether the supplementation can provide long-term benefits to their lambs after weaning. Three experiments were carried out at LincolnSheep, Canterbury, New Zealand, over three sequential years (August 2015-April 2018). Before lambing, twin-bearing crossbred ewes (n=140 in 2015, n=128 in 2016, and n=160 in 2017) were randomly allocated to one of two treatments, viz. supplemented and unsupplemented. Ewes on the supplemented paddocks were introduced to an advantage feeder with approximately 50 g/head/d of sheep pellets starting three weeks before lambing and then increased to 0.5 kg/head/d during the first four weeks of lactation. All sheep were allowed to graze on perennial ryegrass/white clover pasture. After weaning, all lambs were drenched and then exposed to a targeted selective treatment (TST) regime while grazing the areas in which ewes had been or not supplemented to determine if any epidemiological benefit of supplementation existed. Weaned lambs (n=240 in 2015, n=210 in 2016, and n=180 in 2017) originating from each treatment were stratified across the treatment area. For each lamb replicate, growth potential was assessed using sentinel lambs that were treated with a long-acting anthelmintic. The remaining lambs in each replicate were subjected to a TST regime where the need for anthelmintic was based on animals achieving acceptable growth rates. Within each farmlet, lambs were rotationally grazed for the remainder of the grazing season, with lambs grazing freshly grown forages, followed by the ewes. In the first study (year 2015 and 2016, Chapter 4), the ewes were undrenched, consequently allowing the development of pre-existing parasite infections. The results in both years showed that supplementation of ewes did not affect ewe LW and BCS or the weight of lamb weaned per ewe (P>0.05 for all). However, supplementation was successful in reducing ewe's FEC to 50% reduction during lactation periods. However, in 2015, the effect was transient, as FEC of supplemented ewes increased and was not different at week 12 of lactation. In 2015, climatic conditions were not favourable for pasture growth, resulting in low pasture availability, with mean pasture mass declining to less than 700 kg DM/ha in all paddocks, and may have resulted in unintentional nutritional stress and increased the concentration of eggs in the faeces. In the 2016 trial, the reduction in ewe FEC was more consistent throughout lactation, indicating a longer-term benefit to the ewe as this extended beyond the pre-patent period of any larvae that would have been ingested after supplementation. The declining number of eggs observed in 2016 at late pregnancy until the 8th week of lactation agrees with the increase of IgA at the same time, which may be due to an improvement in immunity. However, unexpectedly, the T. colubriformis-specific L3 IgA absorbances in supplemented ewes were significantly lower than unsupplemented ewes throughout the experiment in 2016. The reasons for this are unclear but may reflect differences in the larval challenge. Moreover, supplementation also did not have any significant effects on serum proteins, serum urea, and serum phosphorus of the ewes. Before weaning, there was no difference between the mean LW of lambs reared by supplemented or unsupplemented ewes in 2015 (P=0.27), while in 2016, lambs reared by unsupplemented ewes were significantly heavier than those raised by supplemented ewes (P=0.02). After weaning, there were no differences in the performance of lambs between the two treatments in all years (P>0.05 for all), except for a higher number of drenches administered per lamb (P=0.04) of TST lambs in areas where ewes had not been supplemented in 2015. These findings allowed the conclusion that supplementation of ewes during the first four weeks of lactation had no effect on ewe performance but was successful in temporarily reducing faecal eggs by 50%, presumably reflecting better maintenance of immune function through higher nutrient supply, even though this was not detected in parasite specific-immunoglobulin. However, the reduction in parasite contamination was insufficient to provide a measurable and consistent epidemiological benefit to the grazing lambs after weaning. The second trial (year 2017, Chapter 5) aimed to evaluate the effect of supplementation to reduce the establishment of larvae following short-acting drench pre-lambing. The results showed the benefits of ewe supplementation when the existing population is removed, such as the difference in FEC, the greater serum albumin concentrations, and the consistently higher milk protein contents. Similar to the previous studies, supplementation of ewes in 2017 also did not affect ewe LW and BCS or the weight of lamb weaned per ewe (P>0.05 for all). The reduction in FEC following supplementation was not accompanied by the increase in T. colubriformis-specific L3 IgA absorbance; the values decreased over time (P0.05 for all). There were extremely weak associations between milk production and lamb growth rate during the lactation period, except for the unsupplemented group in week 4 (P

AbstractBackground: In the United States, many mothers are unable to meet their personal breastfeeding goals, or the national and global recommendations for breastfeeding, due to the well documented barriers and reasons for cessation. However, some mothers are continuing to breastfeed longer than six months despite barriers to breastfeeding and residing within a low breastfeeding initiation rate area in a large metropolitan region. Purpose: The purpose of this study is to acquire a better understanding of the social process of sustaining breastfeeding longer than six months, in primarily African American mothers, in regions of a metropolitan area where few mothers start breastfeeding.Methods: Grounded theory methodology, using a critical constructivist lens, will be used to guide the data collection and the iterative, constant comparative, data collection and analysis phase. Semi-structured interviews will be conducted using an inquiry guide through. Data will be collected until theoretical saturation is achieved.Sample: Participants must be 18 years or older, speak fluent English, have attended, or participated in a session or form of support offered by All Mothers Empowered to Nurse (AMEN) breastfeeding support group. Mothers must be a breastfeeding mother who has provided breastmilk to her child for more than six months of age. Theoretical sampling will be employed and continued until saturation of theoretical categories is sufficiently achieved between 10-15 participants. Aim: To construct a theoretical framework explaining the common factors and social processes for breastfeeding in women who have sustained breastfeeding for longer than six months, in a low-income metropolitan area with low-breastfeeding initiation rates, among primarily African American women.

Background: More than half of women return to the workforce within one year following the birth of their child. To continue offering breast milk to their infants and follow AAP and WHO recommendations for breastfeeding, these women often need to express breast milk in the workplace. Registered Nurses who work in bedside roles do not traditionally have access to private office spaces or personal control over their work schedule, making them uniquely susceptible to workplace barriers for expression of breast milk. Currently, the CDC recommends cleaning a breast pump with soap and water and leaving it to air dry after each use. It is unknown what the current knowledge and adherence levels to these recommendations are within a working population or how knowledge and adherence may affect breastfeeding practice outcomes.Objectives: The study was conducted: 1) To determine relationships between employee perceptions of workplace support for expression of breast milk in the workplace (EBMW) and duration of breastfeeding, duration of EBMW, and other infant feeding practices, 2) To describe knowledge of CDC recommendations for cleaning of a breast pump across Registered Nurse (RN), Nurse Manager (NM), and Hospital Representative (HR) groups, 3) To determine if RN knowledge was associated with RN adherence to CDC recommendations for cleaning of a breast pump, 4) To describe relationships between RN breastfeeding practices and: RN knowledge and adherence, NM knowledge, and HR Knowledge, and 5) To learn about the experiences of working RNs who have expressed breast milk in the workplace and provide recommendations to employers for improving employee lactation experiences. Methods: This was a cross sectional research study. Registered Nurse participants who had given birth within the past three years (n=199), Nurse Managers (n = 36), and Hospital Representatives (n = 6) were recruited from 10 hospitals within the county of Los Angeles. Registered Nurses completed four questionnaires online: The Employee Perceptions of Breastfeeding Support Questionnaire (EPBS-Q); the Duration of Breastfeeding, Duration of EBMW, and Infant Feeding Practices Questionnaire (BEIF-Q); the Knowledge of CDC Recommendations for Use and Cleaning of a Breast Pump Questionnaire (KBP-Q); and the Adherence for Use and Cleaning of a Breast Pump according to CDC Recommendations Questionnaire (ABP-Q). Nurse Managers completed two online questionnaires: The Managers' Attitude Toward Breastfeeding Support Questionnaire (MATBS-Q) and the Knowledge of CDC Recommendations for Use and Cleaning of a Breast Pump Questionnaire (KBP-Q). Hospital Representatives completed two online questionnaires: Company Support for Breastfeeding Questionnaire (CBS-Q) and Knowledge of CDC Recommendations for Use and Cleaning of a Breast Pump Questionnaire (KBP-Q). Demographic information was collected from all participants via an online questionnaire. Pearson’s correlation coefficient was used to determine significant associations. Linear regression models were used to determine the relationships between workplace breastfeeding support constructs and breastfeeding and infant practice outcomes; and to explain relationships between knowledge of and adherence to CDC guidelines and breastfeeding and infant feeding practices. Qualitative responses from the open-ended question of the EPBS-Q were analyzed for categories using Strauss and Corbin’s Grounded Theory approach. Open coding, axial coding, and selective coding was used to develop the underlying codes and a conceptual description. Workplace recommendations were then created based upon the analysis. Results: Using the EPBS-Q, increased perceived time and frequency of lactation breaks was associated with an increased duration of feeding solids and breastmilk to the infant, and a decreased duration of solids and formula. Increased communication among coworkers was associated with a decrease in the duration of feeding solids, breastmilk, and formula combined. Among RNs knowledge scores of CDC recommendations for cleaning a breast pump were high, but adherence scores to those recommendations was not as high. There was an association between increased RN adherence to CDC recommendations for cleaning a pump and an increase in the duration of feeding solids and formula to an infant. At the manager level among the hospitals, there was an increase in duration of solids and formula with increased manager knowledge of CDC recommendations for cleaning a pump. Qualitative responses to the open-ended question of the EPBS-Q showed that experiences demonstrating a lack of support for EBMW continue to exist among RNs who expressed breast milk upon return to work.

Deer ( Odocoileus spp.) are an important cultural and economic resource. They are the most popular game species in the United States and the number one driver of conservation funding. On the other hand, they also cause damage to resources including to the agricultural industry, private property and to humans via deer vehicle collisions. Many areas in eastern North America have experienced a decline in white-tailed deer ( Odocoileus virginianus ) populations over the past twenty years concurrent with changes in landscape, deer harvest strategies, and increasing and expanding black bear ( Ursus americanus ) and coyote ( Canis latrans ) populations. Most studies have addressed this problem at small spatial and temporal scales and in areas where predation was assumed to be limiting population growth. We evaluated white-tailed deer fawn recruitment both directly and indirectly at relatively broader spatial and temporal scales. We studied fawn survival on Marine Corps Base Quantico in Virginia, USA from 2008–2019. We used the Kaplan-Meier estimator, and Cox-proportional hazards models to assess annual survival and factors that influence hazard risk such as sex, weather, landscape composition and configuration and food availability. On Marine Corps Base Quantico, we found an increase in red oak mast abundance increases survival and probability of fawn survival was higher during the first interval of the study (2008–2010; 0.71 [0.52–0.96]; survival probability [CI95%]) than the last three intervals (2011–2013; 0.46 [0.30–0.70]; 2014–2016; 0.48 [0.35–0.66] and 2017–2019; 0.50 [0.39–0.63]). We also found that predation was the leading source of mortality. We assessed recruitment using lactation status from hunter harvest data collected by the Virginia Department of Game and Inland Fisheries during a 22-year period in 30 counties in the Appalachian Mountains of western Virginia. We predicted lactation status as a function of landscape composition and configuration, oak mast abundance, weather, age, and predator detection rates using generalized linear mixed models. We found land cover diversity index positively and black bear detection rate negatively influenced recruitment. Age also predicted lactation status with middle-aged females (3.5–4.5 years old) having a higher lactation probability than mature (≥5.5 years old) age and young (2.5 years old) age class deer. Based on these findings, recruitment is likely to be greater in areas that are heterogeneous. Therefore, if an increase in recruitment is desired silvicultural practices such as fire and timber harvest could be used to permanently change land cover types. These silvicultural practices could also be used to increase the number of oaks on the landscape, and augment production of mature oaks as red oak mast abundance influenced fawn survival. Also reducing predation by manipulating predator densities could improve recruitment. Another potential option which needs further research, would be to reduce predator efficiency by increasing hiding cover for fawns.

Maternal-child health authorities recommend that infants breastfeed exclusively for the first six months of life. Currently, 25% of infants in the United States do so. Breastfeeding specific care that mothers receive from their postpartum nurses and lactation specialists is integral to successfully initiating exclusive breastfeeding. Due to the time sensitive nature of establishing milk supply, interrupting the process of lactogenesis with supplementation puts infants at high risk for early termination of breastfeeding. The purpose of this dissertation is to examine the relationship of breastfeeding care received during the postpartum hospital stay, defined as the first 48-72 hours of life, and breastfeeding exclusivity among term, healthy infants. First, an integrated review of the literature was performed to identify aspects of the postpartum hospital experience and behavior of nurses that mothers perceive as helpful or not toward establishing exclusive breastfeeding. Mothers reported they perceived nurses were too busy to help with breastfeeding. When nurses did offer help, their advice was inconsistent between providers and not evidence based. Mothers also noted that providers were hesitant to offer encouragement for a mother’s decision to breastfeed, for fear of causing guilt should the mother experience difficulty. Additionally, special consideration is needed for breastfeeding mothers after cesarean birth. Next, a secondary analysis of data was performed to identify if maternal perception of the hospital experience is a predictor of exclusive breastfeeding during the postpartum hospital stay. Data was retrieved from the control group of a two-part randomized, controlled trial of a breastfeeding education intervention. Forty-five participants were included in this analysis. The outcome of interest was exclusive breastfeeding at hospital discharge and at four weeks after birth. The hospital experience was measured using a survey titled “Every Step Counts”. This 16-question survey measured hospital adherence to the Ten Steps to Successful Breastfeeding, guidelines that promote breastfeeding exclusivity and duration. Rating the hospital experience with a score of 13 or greater was associated with an increased likelihood of breastfeeding exclusively at the time of discharge. The influence of the hospital experience on breastfeeding exclusivity did not remain at four weeks after birth. Finally, a primary investigation was conducted to further examine the relationship between hospital care and exclusive breastfeeding. In this study, a different tool was used to measure breastfeeding care in the hospital. The “Questionnaire for the Breastfeeding Mother” from the hospital self-appraisal and monitoring guide developed by the Baby Friendly Hospital Initiative was distributed on the day of discharge. This study revealed that a higher score on the questionnaire was associated with an increased likelihood of breastfeeding exclusively at discharge. Whether or not a participant’s own mother breastfed was also a predictor of breastfeeding exclusivity at discharge. In summary, quality breastfeeding specific care from nurses and lactation specialists is critical to helping women to establish breastfeeding exclusivity in the immediate postpartum period. Close adherence to the Ten Steps yields positive outcomes of breastfeeding exclusivity. Thus, hospitals could benefit from following the Ten Steps in order to continue the national trend of increasing breastfeeding exclusivity and duration.

n the United States breastfeeding duration and exclusivity rates are not at ideal levels, therefore there is a need to examine existing interventions. The purpose of this systematic review was to examine the effects of education and support interventions during the third trimester, immediate postpartum, and the first six months of life on breastfeeding duration and exclusivity from six weeks to six months. Inclusion criteria were (a) randomized controlled trials or controlled clinical trials, (b) pregnant and/or postpartum women, (c) lactation education and support interventions, (d) measurement of breastfeeding outcomes from six weeks to six months, and (e) published between 2008- 2020. Twenty articles (21 studies) were reviewed. Thirteen studies employed innovative interventions that resulted in statistically significant differences in breastfeeding outcomes between groups. Interventions with statistically significant results were primarily combinations of education and social support and all were provided during the postpartum period. Interventions that targeted both the woman and a support person were more likely to be effective. A limited number of studies targeted the adolescent population and minorities. Common study weaknesses included limited use of a theoretical model, incomplete description of the intervention, and inconsistent outcome definitions and measurements. Based on these results recommendations for future research were derived.

Times of high metabolic activity in gestation and lactation, as well as periods of stress at weaning, can lead to greater incidences of oxidative stress in the dam and offspring during the suckling and post-weaning period. Oxidative stress is an imbalance between prooxidant molecules and the antioxidant defense system that can negatively impact growth and/or reproductive performance. The objective of this research was to evaluate the effectiveness of a yeast cell wall component (Citristim, ADM Nutrition, Quincy, IL), peppermint oil, and ɣ-tocopherol in gestation and lactation diets to alleviate the impact of oxidative stress on maternal reproductive and offspring growth performance from gestation to market. A total of 98 primiparous and multiparous females and their 1,086 offspring were used. In study 1, 45 sows and gilts (240.7 ± 38.5 kg BW) were assigned to one of 4 diets [Control diet (CON), control + yeast cell at 0.2% (YC), control + mint oil top dress at 10 ppm (MO), and control + yeast cell and mint oil top dress (YCMO)] provided from d110 of gestation through to weaning. Weaned offspring were randomly allotted to pens balanced by weight and litter (n=15-17 pens/treatment) within maternal treatment and received the same dietary treatment as the sow during the suckling phase for 35 d post-wean in a 4-phase feeding regimen. In study 2, 53 primiparous and multiparous dams (206.21 ± 35.26 kg BW) were allotted to 4 diet regimens [Control (CON), control + yeast cell top dress at 0.15% (YC), control + mint oil top dress at 10 ppm (MO), and control + ɣ-tocopherol top dress at 200 ppm (GT)] from d5 post-breeding through to weaning. At weaning, piglets were randomly allotted to pens (n=11-19 pens/treatment), balanced by weight and litter within maternal treatment and fed a common diet for 126 d post-wean in a 9-phase feeding regimen. After d29 postwean in study 2, performance of only pigs deemed light (7.25 kg) at weaning were followed to d126. Maternal dietary treatment did not impact sow BW, feed intake, piglet birth weight, and litter size in either study. Sows provided the YCMO diet in study 1 tended to have greater BF (P < 0.10) than YC sows at trial start and maintained a greater BF through to weaning. Superoxide dismutase activity in sow sera, colostrum, and milk did not differ between diets in either study. In study 1, glutathione content in milk tended to be lower (P < 0.10) in MO than YCMO sows with CON and YC intermediate. However, glutathione content in colostrum and d4 and 14 milk samples did not differ by maternal treatment in study 2. At weaning, piglets from YC sows were heavier (P < 0.05) than CON animals in study 1, while in study 2 piglets from GT-fed sows tended to be heavier (P < 0.10) at weaning than YC piglets both due to differences in daily gain. In the post-wean period for study 1, overall daily gain was greater (P < 0.05) for CON-fed pigs than YCMO pigs with overall feed intake greater (P < 0.05) for YCMO than MO resulting in lower (P < 0.05) gain:feed in YCMO-fed pigs vs CON and MO. In study 2, lightweight pigs from CON sows tended to be lighter (P < 0.10) than pigs from all other treatment groups at weaning and d29 post-wean due to differences in daily gain. Lightweight MO and GT pigs were heavier at d42 (P < 0.05) than CON and YC pigs. At d70 post-wean, GT pigs tended to be heavier than CON pigs, with YC and MO intermediate. Lightweight pigs from MO sows had greater gain (P < 0.05) during the finishing period than all other treatment groups, with GT pigs gaining less. There were no detectable differences in BW during the finishing phase among treatments in heavyweight pigs, however, CON pigs tended (P < 0.10) to gain the least. Based on weight category distribution at d6 post-wean a larger percentage of heavy weight YC-fed pigs remained heavy compared to CON-fed pigs in study 1. A greater percentage of lightweight pigs provided the MO diets post-wean were average at the end of the trial period for study 1, with a lesser percentage of MO pigs deemed lightweight at d29 postwean and a larger percentage classified as average in study 2. Inclusion of either test ingredient in both gestation and lactation diets did not impact sow performance with marginal influence on antioxidant status. Exposure to YC and GT during the suckling phase resulted in heavier offspring. However, prenatal and postnatal exposure to MO potentially provided lasting benefits to light-weight pigs resulting in these animals becoming average wean post-wean up to market. Addition of phytochemical oils, particularly mint oil, in gestation and or lactation diet may be advantageous in improving offspring performance from birth to market.

Abstract: Postpartum weight retention (PPWR) is an important risk factor for long-term obesity. Accurate assessment and understanding of energy expenditure and other metabolic characteristics of postpartum women may improve weight management following childbirth. The overall aims of this research were to investigate the energy metabolism profile of postpartum women; and to explore key metabolic characteristics associated with weight retention during this life stage. Additionally, the validity of resting energy expenditure (REE) predictive equations was explored, as well as the accuracy of current recommendations in predicting total energy expenditure (TEE). This was a longitudinal observational study involving women at three (3M-PP; n=52) and nine months postpartum (9M-PP; n=49); some measurements were only undertaken at 9M-PP. Women were stratified as high (>4.8 kg) or low (≤4.8 kg) weight retainers. Energy expenditure and macronutrient oxidation were measured by whole body calorimetry (WBC). Body composition was determined using dual-energy X-ray absorptiometry. Appetite sensations (i.e. hunger, prospective food consumption [PFC], fullness, satiety) were assessed using visual analogue scales, the results of which were then used to calculate a composite appetite score (CAS). Lactation pattern was measured using a 3-day breastfeeding diary including a 24-h infant test weighing protocol. Cardiorespiratory fitness was determined through a fitness test measuring the predicted maximal volume of oxygen consumption (pV̇O2 max). REE was compared to 17 commonly used predictive equations; measured TEE was compared to the Estimated Energy Requirements/DRI equation (EERDRI). This research showed that REE, TEE, and pV̇O2 max were lower in high-retainers than low-retainers. REE at 3M-PP was negatively associated with PPWR at 3M-PP (mean β ± SE: -0.570 ± 0.196, P=0.004) and 9M-PP (-0.688 ± 0.252, P=0.006). An increase in REE from early to late postpartum was observed in low-retainers, which was greater than predicted by changes in body composition. This was not observed in high-retainers. Daily duration of lactation episodes was associated with higher CAS (39.68 ± 15.56, P=0.015), hunger (3.56 ± 1.61, P=0.033), and PFC (4.22 ± 1.78, P=0.023), and with reduced sensations of fullness (-4.18 ± 1.94, P=0.038) and satiety (-3.83 ± 1.87, P=0.048). Women’s perceptions of appetite were associated with PPWR (fullness: -2.97 ± 0.72, P

Background: Decades of rodent research have demonstrated that perinatal maternal choline intake is important for offspring cognition throughout the lifespan, most notably attention and spatial cognition. However, few human studies have evaluated the effect of maternal choline supplementation during pregnancy or lactation on child cognition, particularly during school-age. Objective: To assess the effect of maternal choline supplementation during pregnancy or during exclusive breastfeeding on child cognitive functioning at age 7 years. Design: Women in their 27th week of gestation (“pregnancy cohort”) or in the early postpartum period while exclusively breastfeeding (“lactation cohort”) were recruited to take part in controlled choline feeding studies. Within each cohort, women were randomized to consume either 480 mg choline/d (approximately the Adequate In-take [AI] for pregnancy) or 930 mg choline/d for 12 weeks (pregnancy cohort) or 10 weeks (lactation cohort). Ancillary follow-up studies were conducted to assess child attention, memory, and intelligence at age 7 y. Results: In the pregnancy cohort (n=20), children whose mothers consumed 930 mg choline/d during their 3rd trimester exhibited enhanced attentional control, including improved sustained attention, compared to children whose mothers consumed 480 mg choline/d. Furthermore, children whose mothers consumed 930 mg choline/d during their 3rd trimester exhibited enhanced visuospatial short-term memory capacity compared to children whose mothers consumed 480 mg choline/d. In the lactation cohort (n=18), no consistent benefit of maternal choline supplementation was detected. However, a lack of group differences in breastmilk total choline concentrations in those re-recruited likely precluded a strong test of the hypothesized effects of postnatal maternal choline supplementation on child cognition. Conclusions: Maternal consumption of approximately double the choline AI during the 3rd trimester of pregnancy had beneficial effects on child attention and memory at age 7 y compared to approximately the AI. This study provides the first evidence from a randomized controlled trial that prenatal choline supplementation improves cognitive functioning on behavioral tasks. These preliminary, but compelling, data suggest that the choline AI for pregnancy may not be sufficient to promote optimal offspring cognition. Larger clinical trials are needed to confirm and extend findings from this small follow-up study.

Background: Research has shown up to 80% of mothers perceive their breast milk production as insufficient, which is the most common reason for early cessation of breastfeeding and introduction of galactagogue supplements.Therapeutic use of herbal, food, and pharmaceutical galactagogues has long been believed to help mothers increase breast milk production despite a lack of documented evidence of efficacy. Purpose: This study examined the relationship between galactagogue use and mothers’ breastfeeding self-efficacy, mothers’ perceived insufficient milk supply and breastfeeding duration goal. Methods: A descriptive, cross-sectional study design was used. Between September 2018 and January 2019 a convenience sample of 214 mothers were recruited from pediatricians’ offices when mothers presented for infants’ well newborn visit between 2-21 days postpartum. Mothers completed a one-time study survey comprised of Breastfeeding Self-Efficacy Scale – Short Form (BSES-SF), Perceived Insufficient Milk (PIM), and demographic questions in either English or Spanish. Basic descriptive statistics and unpaired t-test on total BSES-SF score, PIM score, and breastfeeding duration goal by galactagogue use were performed. Based on these results and literature review, hierarchical linear regression models were planned. Results: Of the 199 mothers, most were Hispanic (71%), spoke English (70%), had public insurance (75%), and planned to return to work (67%) at 13 weeks postpartum. Overall, 36% were taking herbal galactagogues and nearly 60% taking foods they perceived would increase their milk supply. There was no statistically significant association between herbal and food galactagogue use and the dependent variables. However, mothers who did not use herbal galactagogue scored 4 point higher on the BSES (p = .06) and had decreased perception of insufficient milk supply than mothers who used herbal galactagogues. Null findings made a regression analysis unnecessary. Conclusions: Recommending use of herbal galactagogues too early may indirectly send the wrong message that mothers are not able to make sufficient breast milk to nourish their babies. Providers need to encourage and educate families and communities on how to support breastfeeding mothers to protect and promote mothers’ breast milk supply starting prenatally, during the first 48 hours during inpatient stay, then up to 1 month old.

The primary hypothesis tested in this experiment is that digestibility of an organic zinc source from polysaccharide-complexed zinc is greater than inorganic zinc sulfate when sows consume high fiber diets containing corn dried distillers grains with solubles (DDGS). Gilts and sows (n = 32) were blocked according to parity and assigned randomly to one of four dietary treatments. Eight sows were assigned to each treatment in four replicate blocks. Dietary treatments consisted of: 1) Control (ConZnSO4) – corn-soybean meal based diet + 100 ppm supplemental Zn from ZnSO4; 2) Control PSZn (ConPSZn) – corn-soybean meal based diet + 100 ppm supplemental Zn from polysaccharide-complexed Zn; 3) DDGS/ZnSO4 – corn-soybean meal-40% DDGS gestation diet and a 30% DDGS lactation diet, with each containing 100 ppm supplemental Zn from ZnSO4; 4) DDGS/PSZn – corn-soybean meal-40% DDGS gestation diet and a 30% DDGS lactation diet, with each containing 100 ppm supplemental Zn from polysaccharide-complexed Zn . A fifth dietary treatment was imposed using a subset of sows (n = 20) to determine basal Zn losses in gestating and lactating sows fed corn and soybean meal based diets containing no supplemental Zn. Nutrient balance experiments were conducted in both gestation and lactation to evaluate digestibility of Zn sources of the four dietary treatments, and to determine basal Zn losses during gestation and lactation when no supplemental dietary Zn was provided. The statistical model consisted of fixed effects of diet, Zn source, and their interaction, and random effects of parity. Sows fed DDGS/ZnSO4 had a greater (P < 0.05) number of pigs weaned per litter (13.4) compared with those fed ConZnSO4 (10.8), ConPSZn (10.4), and DDGS/PSZn (11.9), resulting in decreased average piglet weaning weights (5.6 vs. 7.1, 6.3, 6.7 kg, respectively). These slight differences observed at weaning are not likely associated with dietary treatment, but rather due to numerical differences in piglets born per litter. Furthermore, overall piglet and litter gain among treatments was not different (P > 0.05). Estimated endogenous losses of Zn were used to adjust apparent total tract digestibility (ATTD) to true total tract digestibility (TTTD) of Zn in the four dietary treatment balance periods. There were no differences in Zn concentrations of urine, plasma, colostrum, or milk samples among treatments at any time of the experiment (P > 0.05). Gestating sows fed DDGS/PSZn exhibited improved (P < 0.05) ATTD, TTTD, and overall retention of Zn in comparison to both Control treatments, with the DDGS/ZnSO4 treatment responses being intermediate. Lactating sows consuming diets without DDGS and supplemented with organic Zn exhibited the highest (P < 0.05) ATTD, TTTD, and retention of Zn, which were opposite to responses observed in gestation. Furthermore, ATTD, TTTD, and Zn retention for lactating sows consuming DDGS/PSZn were lower (P < 0.05) than all other treatments. Overall, it appears that stage of pregnancy and dietary fiber affect digestibility and retention of Zn, regardless of Zn source.

The skeletal system is a dynamic organ that provides support, protection, aids in the production of all blood cells, and serves as a calcium ion reservoir. It is constantly undergoing a process called ‘remodeling’, which occurs through the actions of osteoclast and osteoblast cells. The former is responsible for breaking down bone whereas the latter secretes an organic matrix for bone synthesis. Two experiments were conducted to analyze the effects of physiological perturbations on the bone remodeling process. Specifically, the impact of aging and selective serotonin re-uptake inhibitor administration coupled with lactation on bone morphology and composition were observed. The bony skeleton is not a stagnant organ, rather it undergoes functional, mechanical, and compositional changes throughout life. Thus, we wanted to determine the consequences age had on various bone parameters and found a decrease in bone volume fraction (BV/TV), trabecular number (Tb.N), cortical thickness (C.Th), and an increase in periosteal area, endosteal area, and cortical porosity (C.Po). In regards to pregnancy, post-partum depression is a common condition. As a result, many women utilize selective serotonin re-uptake inhibitors (SSRIs) to combat the negative symptoms associated with it. Serotonin is an important hormone involved in mood regulation and the mammary-derived form has a role in lactation. It induces the production of parathyroid hormone-related protein, which is essential for regulating maternal calcium. Because the calcium source for milk production is derived from the maternal bone, we were interested in the impact peri-partum usage of SSRIs had on maternal bone mineral density. Additionally, we sought to understand the effect that circulating SSRIs had on the bone formation of pups. Analysis revealed age-related decreases in BV/TV, Tb.N, trabecular thickness (Tb.Th), C.Th and increases in trabecular spacing (Tb.Sp) and C.Po, with the effects being exacerbated in cohorts treated with a SSRI during lactation. We did not observe, however, any change in trabecular bone mineral density (Tb.BMD) or cortical bone mineral density (C.BMD) over time. In regards to the pups, we observed similar results to those of the dams in addition to a significant reduction in femur length. With the data obtained from the two projects, we hope that they bring awareness to potential consequences that physiological perturbations may have on the bone remodeling process. Both experiments have clinical correlations to humans. Further understanding the relationship between aging and bone may aid in developing methodologies to prevent age-related changes. On the other hand, analyzing the effects that SSRI usage has on maternal and child bone density may result in alternative methods to combat post-partum depression.

Introduction. During lactation, breastfeeders report reduced sexual desire and sexual activity (Von Sydow, 1999). Yet research has not examined the direct impact of suckling on sexuality during lactation. This study looked at breastfeeders, immediately following breastfeeding and several hours later, to determine if the recency of infant suckling influences maternal sexuality. Sexual motivations were also compared between breastfeeders and other mothers. Methods. Mothers of infants between 2 and 7 months of age participated in the repeated measures study online. Participants were randomly assigned to the order of their sessions and participated 20 minutes after breastfeeding or 120 minutes after breastfeeding. Results. In breastfeeders, in-pair sexual desire was significantly lower 20 minutes after breastfeeding than 120 minutes after breastfeeding. Breastfeeders and all mothers in high quality current relationships also reported less extra-pair sexual desire and higher partner-connection sexual motivations than mothers in low quality current relationships. Conclusions. There is some support that the recency of breastfeeding and quality of the pair-bond may impact postpartum sexuality. This research suggests that recent breastfeeding reduces in-pair sexuality and that relationship quality may drive different sexual motivations. Future analyses should utilize greater experimental control on breastfeeding timing, examine hormonal correlates, and include a larger sample size.

All newborn mammals are highly dependent upon milk for nourishment and immune protection. This is especially true for marsupials, a lineage of mammals with a short gestation, limited placental development, and an increased reliance on an extended lactation period. Most newborn marsupials do not receive passive maternal immunity in utero and therefore are entirely dependent upon factors within the milk for immune protection until capable of mounting their own response. In this project we seek to characterize the complex lactation program utilized by marsupials, and seek greater understanding of the maternal role in the establishment of the developing immune system of a model marsupial, the gray short-tailed opossum, Monodelphis domestica. The ontogeny of opossum immune development has been well established, however investigations into correlations with changes in the mammaries during lactation are lacking in this species. Towards these goals, a combination of histology, immunohistochemistry and quantitative PCR was used to investigate mammary development and immune system presence in the opossum mammaries throughout lactation. These investigations have the potential to impact the understanding of the role the immune system plays in mammary development and function from an evolutionary perspective.

Human milk not only provides nutrition and passive immune protection to the infant during early life, but also contains a variety of bioactive components that actively shape the infant’s developing microbiota, metabolism, and immune system. Milk composition varies among mothers and is thought to be shaped by natural selection and ecological inputs from the mother’s environment in order to prepare the infant for the environment it is most likely to encounter during early life. Despite the wide variety of physical and cultural environments humans inhabit around the globe today, the majority of research on human milk composition has been conducted in urban, industrialized settings. As a result, relatively little is known about milk composition in diverse populations. This dissertation utilizes collaborative studies to explore how the composition of human milk varies among mothers from diverse geographic locations and with varying cultural and subsistence practices. First, the composition of innate and acquired immune proteins was compared across seven populations. Acquired immune protein composition was found to be more variable than innate immune protein composition across populations and subsistence strategies. This finding supports the idea that the immune protection provided by milk is shaped by the mother’s immunological exposures throughout her lifetime. Next, the concentrations of seven trace elements were compared in milk from four populations. Calcium was the most variable element investigated, while zinc concentrations did not differ among populations. Cultural practices contributed to higher milk iron concentrations in one population. Finally, the role of cortisol as a signal of maternal energetic condition was explored in two populations. Cortisol concentrations were higher in milk from primiparous mothers and mothers with lower BMI, but milk cortisol concentrations were not significantly related to maternal energy balance or parity. In well-nourished populations, milk cortisol concentrations alone may not be a reliable signal of maternal condition. These studies are among the first characterizations of human milk composition to include indigenous populations and populations practicing traditional subsistence strategies. Together, these results contribute to our understanding of how milk composition varies across diverse populations.

Associations among udder characteristics, milk yield, milk somatic cell counts, lamb growth and prevalence of mastitis were evaluated in 121 twin-suckled crossbred non-dairy ewes at four, eight and twelve weeks after parturition. Milk production per four hours decreased with time, being 1.09 ± 0.04 litres at week four of lactation, 0.68 ± 0.02 litres at week eight and 0.48 ± 0.01 litres at week twelve, and with respective mean somatic cell counts (SCC) of 0.32 x 106 cells mL-1, 0.39 x 106 cells mL-1 and 0.28 x 106 cells mL-1. Incidence of mastitis was 12.7%, 9.8% and 8.9% for weeks 4, 8 and 12, respectively. Of the 20 individuals that displayed SCC indicative of mastitis, only five had elevated SCC at more than one sampling time and none were positive for Staphylococcus aureus. However, S. aureus was present in 1% of the 474 milk samples analysed but only at weeks 4 and 8. There was inconsistent association between SCC and visual scores for udder depth, udder distention, degree of separation or teat placement (P>0.05 for all). Milk volume and weight of lamb was greater (P0.05). The incidence of subclinical mastitis was low but present in this flock with the udder characteristics assessed being poor indicators of either mastitis or milk production, and there was no impact on lamb growth.

Due to high mortality associated with triple negative breast cancer (TNBC), a prevention program has the potential to protect many women against this disease. Recent epidemiological and meta-analysis studies revealed a possible correlation between a lack of breastfeeding and development of TNBC. African-American (AA) women have a disproportionate burden of developing aggressive TNBC, a sub-population with higher parity rates and lower prevalence of breastfeeding. The reasons for why parity and breastfeeding affect breast cancer risk are unclear, but recent studies revealed that the pregnancy-lactation cycle (which leads to remodeling of the mammary glands) alters breast morphology and microenvironment, thereby modifying breast cancer risk. Natural weaning (NW), the gradual cessation of breastfeeding, results in a measured reduction of the ductal structures, termed involution. Conversely, the decision not to breastfeed results in a hastened involution, or abrupt involution (AW). We modeled NW and AW in wild-type mice by restricting breastfeeding to 28 and 7 days respectively. Striking differences in the distribution of cell populations were observed in the mammary glands of AW mice compared to NW mice. Fluorescence activated cell sorting analysis revealed an expansion of the luminal progenitor cells with a concomitant decrease in mammary stem-cell enriched/basal compartment in the glands of the AW cohort. This observation is reminiscent of previous observations in TNBC in both animal models and human pre-neoplastic BRCA1-mutation carrier patients. The AW mammary epithelium is more proliferative, inflammatory, exhibit increased estrogen receptor expression, and is immune active 56 days postpartum. Moreover, we observed more collagen deposition in the AW glands compared with NW, which has been correlated with reduced risk for TNBC. These observations highlight a key difference between the lactating and non-lactating mammary glands at the molecular level that could predispose the AW glands to tumorigenesis. We hope our findings will one day persuade more women to choose breastfeeding as a measure to help prevent TNBC.

Abstract: Docosahexaenoic (DHA) and arachidonic (AA) acids are essential fatty acids found in breast milk and are important for the infant’s brain development and cognitive functions such as those that regulate sleep and crying. The overall goal of this research was to use a large maternal infant cohort, Alberta Pregnancy Outcomes and Nutrition (APrON), to establish the relationship between maternal intake and status of DHA and AA across pregnancy and at three months postpartum, their levels in breast milk and infant sleep and crying outcomes. The cohort participants were mainly older women with a healthy BMI and high socioeconomic status. Dietary intake of DHA and AA was estimated using 24-hr recalls collected at each trimester and at three months postpartum. Food Processor (version 10.6; ESHA Research, Salem, Ore., USA) output was used to estimate AA (n=129, n=564, n=497, n=485 at the four time points, respectively) and a previously established nutrient n-3 database for DHA. DHA from supplement intake was estimated using Supplement Intake Questionnaire (SIQ) and the total DHA intake form diet and supplement was included in the analysis at each time point (n=239, n=998, n=882, n=827, respectively). Maternal blood samples were collected at the same four time points, and the relative percent and concentration of fatty acids in serum PL were assessed by gas liquid chromatography (GLC) (n=280, n=1059, n=713, n=907, respectively). Breast milk samples (n=1038) were obtained at the third month of lactation, and the relative fatty acid composition of DHA and AA was determined using GLC. Brief Infant Sleep Questionnaire (n=785) and Crying Patterns Questionnaire data (n=839) were used to assess the reported durations of infant sleep and crying, and whether parents considered them to be problematic. Statistical analyses were completed using SPSS Version 23.0 (IBM Corporation, Armonk, NY, USA). While AA intake did not change during pregnancy or lactation, DHA intake increased from the second to the third trimester (p=0.01), and the median DHA intake estimate for the cohort did not meet the European Consensus recommendation of 200 mg/day at any time point in the study. The serum concentrations of both DHA and AA increased during pregnancy and decreased postpartum and the relative proportion of DHA followed the same pattern (p

Vitamin D is an essential fat-soluble nutrient that plays a critical role in calcium homeostasis among women of childbearing age. Vitamin D has also been linked to pregnancy health outcomes and may have long-term effects on maternal and child health. Nevertheless, the effects of human pregnancy on vitamin D requirements are poorly understood, and very little is known about placental vitamin D metabolism and its putative effects on maternal circulating pool of vitamin D. The impact of maternal vitamin D status on maternal and fetal bone health is also unclear. As such, my dissertation sought to advance understanding of vitamin D metabolism in human pregnancy, to characterize the effect of the placenta on maternal circulating vitamin D metabolites, and to examine the impact of maternal vitamin D status on maternal and fetal bone health. To achieve these aims, biomarkers of vitamin D status/metabolism were measured in blood and placental tissue obtained from third-trimester pregnant women who participated in a long-term controlled feeding study and consumed equivalent intakes of vitamin D, calcium, and phosphorus. A human placental cell culture model was also used to characterize vitamin D uptake, intracellular metabolism, secretion, and to inform the interpretation of the human study data. The data showed that pregnant women had 30-100% higher (P

The small GTPase Cdc42 is an essential signaling molecule in multiple cellular processes, including proliferation, migration, division and apoptosis. The overexpression of Cdc42 is found in certain breast carcinomas, bringing to question its roles in normal mammary cell function and during breast cancer progression. In this thesis, I have examined the roles of Cdc42 during mammary gland development, and then analyzed the effects of overactive Cdc42 signaling on mammary epithelial cells (MECs). To accomplish this, I used an in vivo mouse model as well as primary cell culture systems. In the initial study, the conditional-knockout of Cdc42 in the epithelia of adult mouse mammary glands resulted in the altered cellular localization of Par complex members, as well as E-cadherin. These changes accompanied a disorganization of the epithelial cells within the mammary gland, and led to insufficient lactation. This loss-of-function mouse model showed that Cdc42 is essential for the proper maintenance of both apical-basal cell polarity and E-cadherin-based cell-cell junctions in the adult mammary gland. These results raised further interest concerning the roles Cdc42 may have in breast carcinoma development, in which proper apical-basal cell polarity and cell-cell communication are commonly lost. I next examined the effects of aberrant Cdc42 signaling in primary MECs by utilizing the constitutively-active Cdc42[F28L] mutant. In a monolayer culture system, Cdc42[F28L] stimulated the formation of actin-based stress fibers, and gave rise to multi-nucleated cells, while in a three-dimensional model system it drove the primary MECs toward an invasive phenotype in an IQGAP1-dependent manner. The primary MECs expressing Cdc42[F28L] lost the proper localization of E-cadherin at cell-cell contacts and no longer formed normal, hollowed alveolar lumens, but instead began to abnormally fill the luminal space and invade out into the surrounding environment. A common phenotype exhibited by these model systems was the proper maintenance of E-cadherin-based cell-cell contacts between mammary epithelial cells. Interestingly, both the deletion of Cdc42 and its constitutive activation resulted in abnormal E-cadherin expression and localization within mammary epithelial cells. IQGAP1 is likely the primary Cdc42 effector responsible for these phenotypes, as it can both regulate E-cadherin stability at cell-cell junctions as well as bundle microtubules at the leading edge of invasive cells. These studies suggest IQGAP1 is a critical signaling effector of Cdc42 in adult mammary epithelial cells and that, when not properly regulated, it can shift the epithelia toward an invasive phenotype.