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Thirty-four cows (26 Holsteins and 8 Jerseys) were subjected to an estrous synchronization protocol administering 2 PGF2Æ Ã injections 11 d apart prior to beginning the lactation-induction protocol. Artificial induction of lactation yielded a 92% success rate for Holstein cows with success defined as achieving >9 kg milk/d, and a 88% success rate for Jersey cows with success defined as achieving > 5 kg milk/d. Mean accumulated milk yield for induced cows at 150 DIM was 65% of mean yield for nontreated cows. Mean peak milk yield for lactation- induced Holsteins and Jerseys was 32 kg/d and 20 kg/d, respectively. Mean serum and milk progesterone concentrations for samples collected during the first 6 d of lactation were not different between lactation-induced and nontreated cows. However, mean serum estradiol concentrations for induced cows were higher (P <0.05) in samples collected 3 and 5 DIM. Lactation-induced cows exhibited an increase in serum alpha-lactalbumin concentrations 2 d prior to initiation of milking, reaching values of ~260 ng/ml. Mean days-to-first service was greatly reduced in cows induced into lactation compared to nontreated cows, while mean services per conception was similar between induced and nontreated cows. Mean days to conception was lower for induced cows than for nontreated cows. By 150 DIM, pregnancy rate of induced cows was 70%, whereas nontreated cows averaged 56% pregnancy rate. / Master of Science

Research has long shown that breastfeeding provides many concrete health benefits for both mothers and infants that other forms of infant feeding do not. As such, unsurprisingly, breastfeeding has been deemed the preferred infant feeding method by the national and global medical communities and widespread initiatives promoting breastfeeding have followed. However, despite being well-intentioned, messaging around breastfeeding has left some people who cannot or choose to not breastfeed feeling othered and inadequate. While the health benefits of breastfeeding should not be understated, there are other experiences and perspectives that deserve to be in the conversation when thinking about breastfeeding and breastfeeding promotion. This thesis seeks to analyze breastfeeding and breastfeeding promotion from a bioethical perspective, providing an alternative lens through which to think critically about the way breastfeeding recommendations and initiatives are impacting real people. In this thesis, I will discuss the history of breastfeeding in the United States, why breastfeeding has come to be the gold standard of infant feeding, and real-life experiences of breastfeeding. I will also analyze breastfeeding, breastfeeding messaging, and current breastfeeding initiatives through the four principles of bioethics: beneficence, maleficence, autonomy, and justice. Lastly, I will offer my view and recommendations on how to incorporate bioethical perspectives into breastfeeding promotional strategies to create a more effective, inclusive, and supportive breastfeeding culture at the individual, community, and national level. / Urban Bioethics

Most of the lipid present in lactating mammary gland cytosol was associated with a high molecular weight aggregate isolated from cytosol by gel exclusion chromatography or by density gradient centrifugation. The major polypeptide constituent of this lipoprotein aggregate was the monomer of fatty acid synthase (FAS). The major milk lipid globule proteins, butyrophilin (8u) and xanthine oxidase (XO), as well as the small GTP-binding protein ARF, also were present. This lipoprotein complex was abundant in cytosol from lactating but not from involuting mammary glands. HPTLC analysis of lipids extracted from the low density FAS (LDFAS) complex demonstrated the presence of the five major milk phospholipids as well as triacylglycerols, cholesterol, unesterified fatty acids, and diacylglycerols. ³²P-labeled phospholipids present in cytosol could be transferred to microlipid droplets (MLD) and endoplasmic reticulum (ER), in vitro, and could be precipitated along with FAS, and other polypeptide constituents of the LDFAS complex. Complexed FAS could be separated from noncorrlplexed FAS by density gradient centrifugation, native PAGE, and gel exclusion chromatography. A large amount of phospholipid consistently was retained with the complexed form of FAS. These results suggest that FAS migrates to a low density fraction by virtue of its association to other proteins and lipids. FAS was found to be associated with ER, intracellular lipid droplets, and the milk lipid globule membrane (MLGM). A similar complex to LDFAS was isolated from ER from liver and mammary gland homogenates following incubation in buffer containing ATP. Polypeptide constituents of this complex had similar electrophoretic patterns to LDFAS, but behaved differently from LDFAS constituents when fractionated with the detergent TX-114. While most of the polypeptides in LDFAS partitioned equally into the detergent and aqueous phases, a constituent with an approximate molecular weight of 70 kDa was enriched in the detergent phase. For the ER-derived FAS complex, most of the polypeptides remained in the aqueous phase but the detergent phase also was enriched with a polypeptide similar in size to the LDFAS detergent enriched constituent. Western blot analysis failed to detect Bu in the ER-derived complex. However, protein disulfide isomerase (PDI) was detected in this complex as well as a polypeptide with approximate molecular weight 50 kDa that cross-reacted with PDI antibody. Extraction of lipids from this ER-derived complex demonstrated the presence of large quantities of unesterified fatty acids, with relatively low amounts of complex lipids. In studies using ¹²⁵I labeled LDFAS, labeled polypeptides were shown to associate with ER and intracellular lipid droplets and their dissociation was stimulated by ATP. Immunocytochemistry using antibody to rat liver FAS revealed distribution of FAS at localized regions of the cytoplasmic surface of rough endoplasmic reticulum and on surfaces of intracellular lipid droplets. Electron micrographs of the LDFAS complex showed a homogeneous morphology of granular, symmetrical particles ranging in size from 40 nm to 170 nm in diameter. These particles resembled low density lipoprotein (LDL) in morphology. From the available data, the following model was proposed for a possible involvement of FAS in lipid droplet secretion in the mammary gland. During active lipogenesis, FAS is targeted to ER membrane by association with a signal or targeting peptide(s) in the cytosol. The signal peptide then binds to selected regions of ER where signal receptors reside. Binding of FAS may initiate synthesis and accumulation of triacylglycerol between ER membrane bilayers. Upon the achievement of a "critical mass", the lipid core may be released into the cytoplasm in an ATP-dependent manner, surrounded by the membrane components that provided the hydrophobic pocket for lipid accumulation. Butyrophilin and the 70 kDa detergent-extractable constituent released from the ER and present in LDFAS are possible sources of such a function. Polypeptides from the cytosolic leaflet of the ER, and proteins peripherally associated with the leaflet then would comprise the polypeptide constituents of the lipid particle. / Ph. D.

The lactational strategy of <u>Thrichomys apereoides</u>, a tropical hystricomorph rodent was examined. Milk composition and yield, and mammary gland composition was determined. / Master of Science

Pigs exposed to chronic intrauterine hyperthermia (gHS) experience greater fat deposition during life and yield carcasses with greater fat:lean content at slaughter compared to pigs gestated under thermoneutral conditions (gTN). The objectives of this study were to 1) determine whether gHS impacts the lactational performance of affected gilts (F1 generation), and 2) determine whether these effects of gHS are also evident in the next generation (F2 generation). Twenty-four gilts were bred and exposed to thermoneutral or heat stressed conditions for the entirety of gestation, and F1 female offspring were retained. At puberty, gHS and gTN gilts were bred to farrow in either spring (March / April) or summer (July / August). Colostrum and milk samples were collected at farrowing and on d 7, 14, and 21 of lactation. At weaning, four offspring (two male, two female) were retained and grown to market weight in mixed-pens under identical management conditions. Carcass characteristics were analyzed at slaughter. Milk nutrient analysis indicated that gHS gilts produced less lactose, and tended to produce greater protein, than did gTN gilts. There was no difference in the growth rate of F2 offspring, but pigs born of gHS dams did have a tendency for greater backfat thickness. The patterns of altered milk nutrient content observed in F1 gilts reflects a metabolic profile consistent with previous gHS research, and the greater backfat of F2 pigs at slaughter indicates the adipose-promoting effects of gHS may be diluted, but still evident, in the second generation. / Master of Science

Thirteen cycling, nonlactating dairy cows were hormonally treated to induce lactation. Starting 7 days after estrus and continuing for 7 days progesterone and estradiol-17β dissolved in absolute ethanol were administered twice daily. Daily dose level for progesterone and estradiol- 178 was .25 mg and .01 mg/kg body weight, respectively. Intramuscular injections of dexamethasone (.028 mg/kg body weight) were given on days 18, 19 and 20 after initial treatment. Mammary tissue biopsies were taken from 9 cows on days 18, 21 and 23 after initiation of treatment (3 cows each day). Histological analysis was performed (> 30,000 contacts) to determine the average percent tissue area composed of epithelium, stroma, lumen, adipose and duct. Difference in percent area between days 18 thru 23 was as follows: (1) epithelium +11.1%, (2) stroma -25.9%, (3) lumen +13.9%, (4) adipose +1.58 and (5) duct -.74%. Also, an increase of 15 nuclei/alveoli occurred between days 18 thru 23. On day 18 small lipid droplet epithelia predominated but was replaced with mixed lipid droplet epithelia by day 23. Day 18 epithelia had elongated dark staining nuclei. Epithelia on day 23 had spherically shaped nuclei containing several nucleoli and a decreased nuclear/cytoplasmic ratio when compared to day 18 epithelia. Four of the hormonally treated cows were allowed to lactate. Production from these four cows ranged from 33 to 74% of the previous lactation. Production and histological development were variable in cows treated with estrogen, progesterone and dexamethasone. / Master of Science

Les maladies métaboliques sont en pleine expansion dans nos sociétés actuelles et constituent un enjeu de santé publique majeur. Les antécédents familiaux, l'environnement et les habitudes de vie de l'individu vont jouer un rôle dans la susceptibilité à certains de ces désordres métaboliques. Sur la base de données épidémiologiques, un lien a été établi entre environnement durant les premières phases de la vie et survenue de pathologies à l'âge adulte conduisant au concept de DOHaD. L'objectif de ce travail était d'étudier, à partir d'un modèle murin, les conséquences de l'exercice physique quotidien de la mère pendant la gestation ou la lactation sur la composition corporelle, la fonction pancréatique et la gestion des substrats énergétiques de la descendance à plus ou moins long terme. L'entraînement maternel avant et pendant la gestation est associé à des modifications de la structure et de la fonction du pancréas de la descendance et semble modifier sa gestion des substrats énergétiques à tous les âges. L'exercice de la mère est également associé à une moindre prise de poids de la descendance et limite sa prise de masse grasse lorsqu'elle est soumise à un régime gras et sucré. L'exercice physique de la mère durant la lactation va modifier la composition du lait et la fonction pancréatique de la descendance. Cependant, il est associé à une augmentation du poids corporel de la descendance adulte mais semble la protéger contre l'insulino-résistance induite par la séparation maternelle. La pratique d'un exercice physique quotidien pendant la gestation et/ou la lactation semble donc modifier le développement et la maturation de certains organes (pancréas, tissu adipeux, foie, muscle squelettique) de la descendance ainsi que sa gestion des substrats énergétiques. Les conséquences de cet entraînement maternel sur la descendance vont être plus ou moins bénéfiques selon son âge et selon son environnement nutritionnel. Ce travail de thèse vient compléter les travaux menés dans le cadre des DOHaD et renforce l'idée que l'environnement lors des premières phases de la vie va avoir des conséquences à plus ou moins long terme sur la santé de l'individu. / Prevalence of metabolic diseases is growing up in our modern societies and constitutes a major public health concern. Family history, environment and lifestyle play a role in the susceptibility to several metabolic disorders. Based on epidemiological data, a link has been established between the environment during the first stages of life and diseases occurrence in adulthood leading to the concept of DOHaD. The aim of this work was to study, using a murine model, the effect of daily maternal exercise during gestation or lactation on offspring body composition, pancreatic function and energy substrates handling on a short- and a long-term basis. Maternal training before and during gestation is associated with changes in offspring pancreas structure and function and in energy substrates handling at all ages. Maternal exercise also decreases offspring body weight gain and fat mass gain when exposed to a high-fat/high sucrose diet. Maternal physical exercise during lactation modifies milk composition and offspring pancreatic function. However, it is associated to an increase in offspring body weight in adulthood but seems to protect against the insulin resistance induced by maternal separation. In conclusion, daily physical exercise during gestation and/or lactation modifies offspring organs development and maturation (such as pancreas, adipose tissue, liver, skeletal muscle) and its energy substrates handling. Maternal training consequences on offspring can be either beneficial or deleterious depending on its age and on its nutritional environment. This work is complementary to studies conducted in the framework of the DOHaD concept and strengthens the idea that the environment during the first stages of life will have short- to long-term impacts on the health of the individual.

Diss. (sammanfattning). Uppsala : Sveriges lantbruksuniv., 2003. / Härtill 4 uppsatser.