Download or read book Nutritional Strategies to Manipulate Milk Fat Synthesis and Fat Storage in Dairy Cows as a Means of Improving Animal Health Production and Reproductive Performance at Various Stages of Lactation written by Jillian Marie Havlin and published by . This book was released on 2014 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Fat metabolism in dairy cows is highly variable over the course of lactation as well as among cows at a similar stage of lactation. Manipulating the ration of dairy cows is a useful tool for modifying fat metabolism, particularly how cows partition fat for milk fat synthesis versus storage as an energy source. Transition cows (i.e., cows approaching calving and beginning to lactate) experiences a negative energy balance (NEB), making them highly susceptible to a large range of post-partum health problems (e.g. ketosis, fatty liver, displaced abomasum) and reduced milk production. Therefore ability to abate severe NEB in transition cows through nutritional modifications would be a very efficacious. Ruminally-protected niacin (RPNi) is a lipolytic B-vitamin that may be able to block lipolysis during severe NEB, thereby reducing the incidence of ketosis and other post-partum diseases. To evaluate effects of feeding RPNi to post-partum cows, 997 fresh cows (i.e., cows between 1 and 28 days in milk (DIM)) were fed niacin, in the form of nicotinic acids (NA) for the first 14 to 28 DIM at one of 4 treatment levels (0, 3.5, 7, 14 g NA/cow/d). After 28 DIM cows were moved from fresh pens to early lactation pens where they remained until 150 DIM, and no RPNi was fed. At the lower dose of RPNi (i.e., 3.5 g NA) cows experienced an improvement in milk (P=0.10), fat (P=0.11), and energy yield (P=0.07) while on treatment, but when RPNi was removed from the ration milk (P=0.04), fat (P=0.10) and energy yields (P=0.06) decreased, compared to Control cows. Cows treated with low dose RPNi experienced a 16.3% decrease in prevalence of ketosis (P=0.06) and a 2.2 kg increase in dry matter (DM) intake (P=0.07) during the fresh period. The BCS of cows did not differ during the fresh period. Although the BCS of low dose RPNi cows decreased more (P=0.01) after moving to the high cow pen, BCS did not differ at 138 DIM. Conversely, cows treated with the higher dose PRNi (i.e., 14 g NA) experienced a decrease in milk (P=0.10), fat (P=0.11), and energy yields (P=0.07) while on treatment, but when RPNi treatment ended milk (P=0.04), fat (P=0.10), and milk energy (P=0.06) increased, with eventual convergence with Control cows. The high dose of RPNi did not affect ketosis prevalence, DM intake or BCS in the fresh pen. While Control cows began to regain BCS at the third sampling, high dose RPNi cows continued to lose BCS over the third (P=0.04) and fourth (P=0.10) BCS sampling in the high pens. The absence of change in BCS and blood NEFA levels indicates that the low dose of RPNi did not reduce lipolysis in adipose, but did aid in shifting the metabolism of NEFA away from ketogenesis towards the more efficient tricarboxylic acid (TCA) cycle, thereby reducing ketosis and increasing milk production yields. It is likely that high level RPNi feeding initially blocked lipolysis, but to an extent that cows were pushed in to very severe NEB, resulting in the decreased DM intake and maintained high ketosis prevalence. As feeding RPNi at any level had minimal effect on BCS and no effect on prevalence of NEB, no change in fertility parameters was as expected. After cows traverse the fresh pen, and progress through lactation, the metabolic focus shifts towards increasing and maintaining high productivity. One of the most common ways to improve milk production is by feeding fat to improve the NE density of the ration. Although not all dietary lipids have the same effects on fat utilization in the cow, particularly milk production and fat storage, two of the key components of dietary fat that have the greatest effect are the fat level of the ration and its saturation. To examine how these two parameters effect milk production metabolism, especially milk fat yield and BCS, three rations were fed to early lactation cows: A low fat control ration (LFC), and two isocaloric "high fat" rations, where one was high in polyunsaturated fatty acids (PUFA) from corn oil (HFU), and the second was high in saturated fat due to inclusion of a rumen-inert Ca-salt of fatty acids (HFS). Cows fed the HFS ration had increased milk, fat, protein, and milk energy yields (P

Download or read book Animal Agriculture written by Fuller W. Bazer and published by Academic Press. This book was released on 2019-10-25 with total page 558 pages. Available in PDF, EPUB and Kindle. Book excerpt: Animal Agriculture: Sustainability, Challenges and Innovations discusses the land-based production of high-quality protein by livestock and poultry and how it plays an important role in improving human nutrition, growth and health. With exponential growth of the global population and marked rises in meat consumption per capita, demands for animal-source protein are expected to increase 72% between 2013 and 2050. This raises concerns about the sustainability and environmental impacts of animal agriculture. An attractive solution to meeting increasing needs for animal products and mitigating undesirable effects of agricultural practices is to enhance the efficiency of animal growth, reproduction, and lactation. Currently, there is no resource that offers specific knowledge of both animal science and technology, including biotechnology for the sustainability of animal agriculture for the expanding global demand of food in the face of diminishing resources. This book fills that gap, giving readers all the necessary information on important issues facing modern animal agriculture, namely its sustainability, challenges and innovative solutions. Integrates new knowledge in animal breeding, biotechnology, nutrition, reproduction and management Addresses the urgent issue of sustainability in modern animal agriculture Provides practical solutions on how to solve the current and future problems that face animal agriculture worldwide

Download or read book Dietary Source and Availibility i e Availability of Fatty Acids to Manipulate Ruminal Protozoa Metabolism of Fat and Milk Fatty Acid Profile in Lactating Dairy Cows written by Carine Reveneau and published by . This book was released on 2008 with total page 152 pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract: With the increasing environmental concern for N excretion in the environment, the nutrition of dairy cows meets new challenges to maintain milk production while decreasing dietary protein. Various strategies to improve efficiency of N utilization in milk production have been developed. Decreasing protozoal abundance and the corresponding improvement of microbial protein efficiency could improve this efficiency of dietary protein utilization. The feeding of fat usually decreases the abundance of protozoa but can have detrimental effect on ruminal fermentation and milk fat production, thus needing further study to ascertain the potential benefits relative to potential detriments. In a first study, the effects of the availability of dietary fatty acids from cottonseed oil on ruminal metabolism and milk fat production were investigated. In our study, feeding a mix of pelleted and delinted cottonseeds appeared to modify ruminal fatty acid metabolic processes, decreasing the risk of milk fat depression and tending to increase dry matter intake and milk production over time compared with conventional or pelleted cottonseeds. In a second study, the effects of feeding Rumensin (R) in combination with animal vegetable (AV) fat or coconut oil were fed to six rumen-cannulated dairy cows. Using omasal collection, I measured microbial protein efficiency and nutrient digestibility. By feeding R to control the extent of amino acid deamination and combined with fat to control protozoal abundance, the efficiency of microbial protein synthesis might be improved in dairy cows. Animal vegetable fat can be biohydrogenated in the rumen and decrease its effectiveness, but diets supplemented with coconut oil (CO; rich in medium chain FA) are more consistent in inhibiting protozoa. Total protozoal abundance was decreased by CO supplementation for all genera expect for Epidinium, which maintained its numbers but was decreased by AV+R. The low acetate to propionate ratio for CO was associated with a decreased ruminal NDF digestibility. There was no effect of diet on efficiency of microbial protein synthesis. DMI was 5 kg/d lower with CO. Milk production was lower when cows were fed CO than AV and when diets contained R. Milk fat depression (MFD) occurred with AV+R and CO. The decrease in protozoal abundance was not associated with an increase in microbial protein efficiency. The detrimental effect of CO on DMI affected the energy available for milk synthesis Omasal flows of FA were characterized by an increased percentage of trans 18:1 for AV and CO diets, a higher percentage of 12:0 and 14:0 for CO, and higher cis 18:1 for AV. Milk FA composition reflected the changes observed for omasal FA digesta flow. The de novo FA synthesis in the mammary gland was inhibited with R and F supplementation. Higher trans 18:1 FA in milk fat was also observed for AV and CO. The feeding of CO did not prevent MFD, and no interactions between R and S were detected. The feeding of CO did compromise ruminal biohydrogenation, with accumulation of trans 18:1 in the rumen and in milk fat.

Download or read book Review on Effect of Feeding Dairy Cow with Protected Fat and Protein on milk Yield and its Composition written by Tamene Bayisa and published by GRIN Verlag. This book was released on 2018-03-13 with total page 31 pages. Available in PDF, EPUB and Kindle. Book excerpt: Seminar paper from the year 2017 in the subject Veterinary medicine, Jimma University College of Agriculture and Veterinary Medicine, language: English, abstract: Objective of this review is focus on effect of feeding protected fat and protected protein on milk yield and its composition and how these nutrients are protected. Many researchers in this review investigate that the responses are highly dependent on the type of fat and protein supplement and the stage of lactation. A higher milk response was observed with saturated than with unsaturated fat supplements. Diet with added fat increase milk production compared with a control diet without added fat in cows. Feeding of bypass fat resulted in significant increase in milk yield and Fat Corrected Milk yield particularly in early lactation. The source of Protected fat are (origin (animal, plant, processed or whole oilseeds, calcium salts) and Cereal Grains such as corn, wheat, Barly, oil seeds, sun flower, cotton seed, soybeans and canola). The supplementation of protected protein in the diets of lactating animals increases the milk yield due to proportionate increase in the supply of amino acids to the host postruminally Milk yield in cows fed protected methionine for the whole experimental period was numerically higher than in cows of the other groups. However, the difference was not statistically significant .At the centeral high land of Ethiopia the Treatment of shredded wheat and barley straw with urea, molasses, salt and water prior to feeding is a technology that should be considered . Cows with excessive body tissue mobilisation at this stage may take up to 20 weeks to regain a positive energy balance status. Key words milk yield, composition ,protected fat , protein protected

Download or read book Changing the Dietary Ratio of Fatty Acids Under Different Physiological Conditions Alters Energy Partitioning of Dairy Cows written by Jonas de Souza and published by . This book was released on 2018 with total page 219 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Nutrient Requirements of Dairy Cattle written by National Research Council and published by National Academies Press. This book was released on 2001-02-09 with total page 406 pages. Available in PDF, EPUB and Kindle. Book excerpt: This widely used reference has been updated and revamped to reflect the changing face of the dairy industry. New features allow users to pinpoint nutrient requirements more accurately for individual animals. The committee also provides guidance on how nutrient analysis of feed ingredients, insights into nutrient utilization by the animal, and formulation of diets to reduce environmental impacts can be applied to productive management decisions. The book includes a user-friendly computer program on a compact disk, accompanied by extensive context-sensitive "Help" options, to simulate the dynamic state of animals. The committee addresses important issues unique to dairy science-the dry or transition cow, udder edema, milk fever, low-fat milk, calf dehydration, and more. The also volume covers dry matter intake, including how to predict feed intake. It addresses the management of lactating dairy cows, utilization of fat in calf and lactation diets, and calf and heifer replacement nutrition. In addition, the many useful tables include updated nutrient composition for commonly used feedstuffs.

Download or read book Metabolic Modifiers written by National Research Council and published by National Academies. This book was released on 1994-02-01 with total page 94 pages. Available in PDF, EPUB and Kindle. Book excerpt: In the past decade, animal scientists have learned that administering recombinantly derived somatotropin (growth hormone) to cows improves milk production and that giving beta-adrenergic agonists to meat animals improves productivity and leanness. In order for these metabolic modifiers to yield benefits, however, sound management of the animals' nutrition is necessary. This volume reports on how these substances work in the animals' metabolism, what effects they might have on nutrient requirements of domestic livestock, and what information should be developed further by investigators. The book explores the current understanding of the biology, structure, mechanisms of action, and treatment effects of somatotropin, beta-adrenergic agonists, and anabolic steroids. A companion volume to the Nutrient Requirements of Domestic Animals series, this authoritative volume will be required reading for animal scientists, researchers, veterinarians, livestock farmers, and faculty and students in university animal veterinary science programs.

Download or read book The Use of Drugs in Food Animals written by National Research Council and published by National Academies Press. This book was released on 1999-01-12 with total page 276 pages. Available in PDF, EPUB and Kindle. Book excerpt: The use of drugs in food animal production has resulted in benefits throughout the food industry; however, their use has also raised public health safety concerns. The Use of Drugs in Food Animals provides an overview of why and how drugs are used in the major food-producing animal industriesâ€"poultry, dairy, beef, swine, and aquaculture. The volume discusses the prevalence of human pathogens in foods of animal origin. It also addresses the transfer of resistance in animal microbes to human pathogens and the resulting risk of human disease. The committee offers analysis and insight into these areas: Monitoring of drug residues. The book provides a brief overview of how the FDA and USDA monitor drug residues in foods of animal origin and describes quality assurance programs initiated by the poultry, dairy, beef, and swine industries. Antibiotic resistance. The committee reports what is known about this controversial problem and its potential effect on human health. The volume also looks at how drug use may be minimized with new approaches in genetics, nutrition, and animal management.

Download or read book Feeding Supplemental Fat to Enhance Fertility in the Dairy Cow written by Amy Mowrey and published by . This book was released on 2000 with total page 190 pages. Available in PDF, EPUB and Kindle. Book excerpt: Historically speaking, fertility has decreased and milk yield has increased in modern dairy cows. This has led to a large amount of research focusing on increasing pregnancy rate in lactating cows. Some believe that an increase in nutrients fed to early lactation dairy cows is required for high milk production and reproductive function. To test this hypothesis researchers have tried to increase the energy density of the diet or to feed different types of fat (an energy dense nutrient). Three experiments were conducted to test the effects of type and amount of fat fed to lactating dairy cows on fermentation, production and reproductive function. The first experiment compared a control diet (no supplemental fat) to type of raw soybean (cracked or ground) and a rumen inert fat source. Each diet was fed to four rumen-cannulated midlactation dairy cows. The only fermentation parameter affected by diet was the solids passage rate, which decreased for the cracked soybean diet. Reproductive parameters were unchanged by dietary treatments. The second set of experiments tested these diets and others for a longer period of time using more animals. One hundred and fifty-two early lactation dairy cows were fed different levels of fat in a study completed over two years (Year One (Y1) n 84; Year Two (Y2) n = 68). Year One cows were fed a control diet, one with added soybeans, or one containing a rumen-inert fat product. Pretreatment and experimental milk yield were significantly higher for cows fed the control and soybean diets. This was due to random assignment of lower BW cows to the treatment containing the rumen inert fat product. We concluded that no difference due to treatment occurred but instead the difference was due to BW differences. During Y2 cows were fed a control diet or three diets increasing in soybean content. Milk protein percentage decreased as soybeans were added to the diet. Other production parameters were similar across treatments. Plasma cholesterol at week 10 of lactation and amount of total fatty acids in plasma increased with increasing soybean content. Number of estrous cycles for cows fed the lowest soybean diet during Y2 was the only significant change in the reproductive parameters measured for both years. In summary, early lactation dairy cows maintained intake and milk production levels similar to control cows when fed supplemental fat, after taking BW into account. Small changes were noted in plasma fatty acid content and cholesterol during Y2, but these increases were not translated into increases in progesterone concentration or changes in reproductive efficiency or function.

Download or read book Nutrient Requirements of Laboratory Animals written by National Research Council and published by National Academies Press. This book was released on 1995-02-01 with total page 188 pages. Available in PDF, EPUB and Kindle. Book excerpt: In the years since the third edition of this indispensable reference was published, a great deal has been learned about the nutritional requirements of common laboratory species: rat, mouse, guinea pig, hamster, gerbil, and vole. The Fourth Revised Edition presents the current expert understanding of the lipid, carbohydrate, protein, mineral, vitamin, and other nutritional needs of these animals. The extensive use of tables provides easy access to a wealth of comprehensive data and resource information. The volume also provides an expanded background discussion of general dietary considerations. In addition to a more user-friendly organization, new features in this edition include: A significantly expanded section on dietary requirements for rats, reporting substantial new findings. A new section on nutrients that are not required but that may produce beneficial results. New information on growth and reproductive performance among the most commonly used strains of rats and mice and on several hamster species. An expanded discussion of diet formulation and preparationâ€"including sample diets of both purified and natural ingredients. New information on mineral deficiency and toxicity, including warning signs. This authoritative resource will be important to researchers, laboratory technicians, and manufacturers of laboratory animal feed.

Download or read book The Role of Metabolic Signaling in Nutrient Partitioning During Lactation written by Virginia Pszczolkowski and published by . This book was released on 2023 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis examines the hypothesis that metabolic signaling regulates how nutrients are partitioned to support milk synthesis during lactation, with particular emphasis on the dairy cow. First we explored the role of the protein complex mTORC1, a cellular hub of metabolic regulation, in mediating dietary amino acid regulation of murine lactation. Kinase activity of mTORC1 positively regulates cellular anabolic signaling, including protein translation and fat synthesis. Amino acids are both the substrate for protein synthesis-including milk protein-and intracellular signaling molecules that stimulate mTORC1. Feeding lactating animals a protein-restricted diet, therefore, should limit the substrate supply for milk synthesis, as well as reduces anabolic signaling driving that synthesis. Increasing the synthesis of milk components, by definition, means that those components' precursors are simultaneously being partitioned to the synthesizing tissue. We hypothesized that inhibiting mTORC1 activity would reduce lactation performance similarly to restricting protein. We fed lactating mice isoenergetic diets containing adequate protein or restricted protein, and treated half of the adequate protein dams with the mTORC1 inhibitor rapamycin. The dams receiving rapamycin under an adequate protein background and the dams receiving the protein-restricted diet all exhibited reduced pup growth and milk production. In this way, we demonstrated that pharmacologic inhibition of mTORC1 mimics dietary protein restriction in lactating mouse dams, positioning mTORC1 signaling as essential in milk production and successful lactation.Next, we further examined mTORC1 signaling in MAC-T, an immortalized mammary epithelial cell line. Amino acids function to induce mTORC1 localization to the lysosome, where its insulin-activated binding partner Rheb resides. In other models, it has been established that in order for mTORC1 activity to commence following amino acid-driven lysosomal localization, insulin signaling must also be present. We hypothesized that this was also the case in MAC-T. By testing the response in mTORC1 activity to varying concentrations of individual amino acids and insulin, we found that, out of the 10 essential amino acids, only Arg, Ile, Leu, Met, and Thr activate mTORC1 signaling in MAC-T cells, and that this activation requires concurrent stimulation by insulin for greatest response. Following the establishment of which amino acids best interact with insulin to regulate mTORC1 activity in a mammary epithelial cell line, we then sought to test this interaction in lactating cows. We hypothesized that the combination of insulin with Leu and Met-two of the amino acids identified as key in our in vitro study-would result in improved mammary utilization of nutrients for milk synthesis. In this cow study, we raised circulating insulin by means of the hyperinsulinemic-euglycemic clamp, and increased circulating Leu and Met by abomasal infusion. We found that the simplicity suggested by our in vitro experiment belies the complexity of lactation in a cow: there was no interaction between insulin and the amino acids, nor did either treatment independently result in any positive effects on mammary utilization of nutrients or milk production. We did, however, observe responses in plasma concentrations of several nutrients and metabolites, including free fatty acids and amino acids, which were reduced in response to insulin. Insulin is a particularly complex hormone in the context of a lactating dairy cow, because despite the necessity of insulin signaling for cellular metabolic functions like mTORC1 activity in the mammary cells, insulin can also reduce the availability of nutrients for the mammary gland by inducing uptake in non-mammary tissues. Because we did not see evidence that the free fatty acids nor amino acids decreased in circulation were being utilized by the mammary glands for milk synthesis, it is likely that in the context of this experiment, insulin instead stimulated nutrient uptake by other insulin sensitive tissues, partitioning nutrients away from the mammary glands. As insulin partitions nutrients away from the mammary glands, we then sought to investigate the effect of serotonin in nutrient partitioning, a hormone that in lactating cows has been shown to decrease circulating insulin concentration, act as an autocrine-paracrine regulator of mammary and calcium homeostasis in lactation, and perform a variety of other metabolic roles outside of lactation. We raised peripheral serotonin in lactating cows by intravenously infusing them with the serotonin precursor 5-HTP and conducted several experiments in these cows over the course of three weeks to investigate how serotonin may participate in nutrient partitioning to the mammary glands. In performing an intravenous glucose tolerance test on the cows, we determined that elevated serotonin both reduced the insulin response and blunted the decrease in free fatty acids following the glucose challenge, without altering the glucose dynamics themselves. The maintenance of normoglycemia under lower insulin conditions, coupled with elevated free fatty acids, suggests that serotonin stimulates insulin-independent glucose disposal, and increases free fatty acid availability for mammary gland usage. When we then assessed serotonin's broader effects on metabolic function, mammary extraction of nutrients, and subsequent milk production, we found transiently decreased circulating insulin, increased circulating free fatty acids, and increased mammary free fatty acid extraction, all of which indicate increased free fatty acid partitioning to the mammary glands. This partitioning was not, however, borne out in improved milk production, which was instead decreased in concert with infusion of 5-HTP. Elevated serotonin also increased the incidence and frequency of loose manure during and shortly after infusion, in line with its known effects on gut motility, and reduced feed intake in a manner antithetical to the support of lactation. This work in serotonin may have been limited by the experimental approach used, with 5-HTP rather than serotonin itself administered in a bolus fashion, potentially driving strongly transient effects in both the periphery and central nervous system. This could effect serotonergic responses that are disparate from what is possible with endogenous mammary serotonin production alone. Overall, through the work of this dissertation, we have identified the importance of insulin in cellular signaling within the mammary epithelial cells to drive milk synthesis, but also that, within the physiologic context of a lactating animal, insulin has non-mammary functions that may contradict its signaling role in mammary cells, reducing substrate availability for milk synthesis. As with insulin, peripheral serotonin is part of a complex system that can yield equally complex outcomes. While serotonin can improve milk substrate availability in the circulation and improve the mammary extraction of some of those substrates, it can simultaneously reduce the availability of other substrates by limiting their availability and absorption from the diet. Broadly, understanding how amino acids, insulin, and serotonin interact to regulate metabolism function during lactation will better position lactation physiologists and nutritionists to understand and manipulate metabolism during lactation. In this way, this work advances the pursuit of improved productive efficiency and treatment and prevention of metabolic disorders in dairy cows.

Download or read book Relationships Between Carbohydrate Nutrition and Metabolism Inflammation and Performance of Dairy Cattle During the Periparturient Period written by Sarah Elizabeth LaCount and published by . This book was released on 2019 with total page 282 pages. Available in PDF, EPUB and Kindle. Book excerpt: The transition from pregnancy to lactation is a time of great metabolic adaptations for the dairy cow. Dry matter intake decreases, yet demand for nutrients increase vastly with the onset of milk production resulting in negative energy balance. Cows must mobilize body tissues to increase energy for the body while sparing glucose for the mammary gland. Due to this increased metabolic demand and negative energy balance, cows often end up in a state of metabolic dysfunction which can have disastrous consequences. Nutritional strategies can help increase glucose precursors while decreasing body tissue mobilization that is linked to increased risk of disease. Previous research is mixed on the impacts of high starch to increase glucose precursors to the cow immediately postpartum, likely due to an increased risk for subacute ruminal acidosis that can result in metabolic dysfunction and inflammation. Feeding strategies which utilize high starch while also including higher fiber to promote rumen health have not been conducted. The objectives of this dissertation were to: 1) investigate interplay of fiber fractions in high starch postpartum dairy cow diets on performance, hepatic metabolism and energy balance, 2) examine interplay of inflammation, hepatic metabolism, energy metabolites, and metabolic hormones in the postpartum period, and 3) investigate opportunities to combine use of a higher digestibility corn silage with monensin to optimize production and health in the periparturient period. Increased fiber in the postpartum diet can limit intake in early lactation, resulting in negatively altered metabolism and production. As intake restrictions were eased by feeding a more fermentable diet, cows were able to recover intake, production, and energy metabolites in a matter of days to match cows that were not limited in intake early postpartum. Increased fiber in diets that may pose a higher risk of subacute ruminal acidosis may still be warranted, though further research on fiber levels and fractions is needed. Correlations between improved hepatic metabolism and metabolic hormones indicative of energy balance were positive, though correlations between markers of improved hepatic metabolism and inflammation were negative. Cows fed corn silage with higher digestibility and monensin, which increases glucose precursors, showed a possible synergistic effect on milk production. Using either strategy alone increased energy status, improved metabolism and health status, however a combination of both strategies decreased milk components, indicating they might negatively alter the rumen environment and milk fat synthesis.

Download or read book The Role of Metabolic Signaling in Nutrient Partitioning During Lactation written by Virginia Loretta Pszczolkowski and published by . This book was released on 2023 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis examines the hypothesis that metabolic signaling regulates how nutrients are partitioned to support milk synthesis during lactation, with particular emphasis on the dairy cow. First we explored the role of the protein complex mTORC1, a cellular hub of metabolic regulation, in mediating dietary amino acid regulation of murine lactation. Kinase activity of mTORC1 positively regulates cellular anabolic signaling, including protein translation and fat synthesis. Amino acids are both the substrate for protein synthesis-including milk protein-and intracellular signaling molecules that stimulate mTORC1. Feeding lactating animals a protein-restricted diet, therefore, should limit the substrate supply for milk synthesis, as well as reduces anabolic signaling driving that synthesis. Increasing the synthesis of milk components, by definition, means that those components' precursors are simultaneously being partitioned to the synthesizing tissue. We hypothesized that inhibiting mTORC1 activity would reduce lactation performance similarly to restricting protein. We fed lactating mice isoenergetic diets containing adequate protein or restricted protein, and treated half of the adequate protein dams with the mTORC1 inhibitor rapamycin. The dams receiving rapamycin under an adequate protein background and the dams receiving the protein-restricted diet all exhibited reduced pup growth and milk production. In this way, we demonstrated that pharmacologic inhibition of mTORC1 mimics dietary protein restriction in lactating mouse dams, positioning mTORC1 signaling as essential in milk production and successful lactation.Next, we further examined mTORC1 signaling in MAC-T, an immortalized mammary epithelial cell line. Amino acids function to induce mTORC1 localization to the lysosome, where its insulin-activated binding partner Rheb resides. In other models, it has been established that in order for mTORC1 activity to commence following amino acid-driven lysosomal localization, insulin signaling must also be present. We hypothesized that this was also the case in MAC-T. By testing the response in mTORC1 activity to varying concentrations of individual amino acids and insulin, we found that, out of the 10 essential amino acids, only Arg, Ile, Leu, Met, and Thr activate mTORC1 signaling in MAC-T cells, and that this activation requires concurrent stimulation by insulin for greatest response. Following the establishment of which amino acids best interact with insulin to regulate mTORC1 activity in a mammary epithelial cell line, we then sought to test this interaction in lactating cows. We hypothesized that the combination of insulin with Leu and Met-two of the amino acids identified as key in our in vitro study-would result in improved mammary utilization of nutrients for milk synthesis. In this cow study, we raised circulating insulin by means of the hyperinsulinemic-euglycemic clamp, and increased circulating Leu and Met by abomasal infusion. We found that the simplicity suggested by our in vitro experiment belies the complexity of lactation in a cow: there was no interaction between insulin and the amino acids, nor did either treatment independently result in any positive effects on mammary utilization of nutrients or milk production. We did, however, observe responses in plasma concentrations of several nutrients and metabolites, including free fatty acids and amino acids, which were reduced in response to insulin. Insulin is a particularly complex hormone in the context of a lactating dairy cow, because despite the necessity of insulin signaling for cellular metabolic functions like mTORC1 activity in the mammary cells, insulin can also reduce the availability of nutrients for the mammary gland by inducing uptake in non-mammary tissues. Because we did not see evidence that the free fatty acids nor amino acids decreased in circulation were being utilized by the mammary glands for milk synthesis, it is likely that in the context of this experiment, insulin instead stimulated nutrient uptake by other insulin sensitive tissues, partitioning nutrients away from the mammary glands. As insulin partitions nutrients away from the mammary glands, we then sought to investigate the effect of serotonin in nutrient partitioning, a hormone that in lactating cows has been shown to decrease circulating insulin concentration, act as an autocrine-paracrine regulator of mammary and calcium homeostasis in lactation, and perform a variety of other metabolic roles outside of lactation. We raised peripheral serotonin in lactating cows by intravenously infusing them with the serotonin precursor 5-HTP and conducted several experiments in these cows over the course of three weeks to investigate how serotonin may participate in nutrient partitioning to the mammary glands. In performing an intravenous glucose tolerance test on the cows, we determined that elevated serotonin both reduced the insulin response and blunted the decrease in free fatty acids following the glucose challenge, without altering the glucose dynamics themselves. The maintenance of normoglycemia under lower insulin conditions, coupled with elevated free fatty acids, suggests that serotonin stimulates insulin-independent glucose disposal, and increases free fatty acid availability for mammary gland usage. When we then assessed serotonin's broader effects on metabolic function, mammary extraction of nutrients, and subsequent milk production, we found transiently decreased circulating insulin, increased circulating free fatty acids, and increased mammary free fatty acid extraction, all of which indicate increased free fatty acid partitioning to the mammary glands. This partitioning was not, however, borne out in improved milk production, which was instead decreased in concert with infusion of 5-HTP. Elevated serotonin also increased the incidence and frequency of loose manure during and shortly after infusion, in line with its known effects on gut motility, and reduced feed intake in a manner antithetical to the support of lactation. This work in serotonin may have been limited by the experimental approach used, with 5-HTP rather than serotonin itself administered in a bolus fashion, potentially driving strongly transient effects in both the periphery and central nervous system. This could effect serotonergic responses that are disparate from what is possible with endogenous mammary serotonin production alone. Overall, through the work of this dissertation, we have identified the importance of insulin in cellular signaling within the mammary epithelial cells to drive milk synthesis, but also that, within the physiologic context of a lactating animal, insulin has non-mammary functions that may contradict its signaling role in mammary cells, reducing substrate availability for milk synthesis. As with insulin, peripheral serotonin is part of a complex system that can yield equally complex outcomes. While serotonin can improve milk substrate availability in the circulation and improve the mammary extraction of some of those substrates, it can simultaneously reduce the availability of other substrates by limiting their availability and absorption from the diet. Broadly, understanding how amino acids, insulin, and serotonin interact to regulate metabolism function during lactation will better position lactation physiologists and nutritionists to understand and manipulate metabolism during lactation. In this way, this work advances the pursuit of improved productive efficiency and treatment and prevention of metabolic disorders in dairy cows.

Download or read book Feeding Strategies to Improve Sustainability and Welfare in Animal Production written by Fulvia Bovera and published by MDPI. This book was released on 2021-04-23 with total page 535 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book contains the scientific contributions published within the Animals topical collection “Feeding Strategies to Improve Sustainability and Welfare in Animal Production”. Originally a Special Issue, it has turned into a permanent collection, with its first article being published in July 2019 and more than 30 published articles a year later: evidence of the great interest from the scientific community regarding the topics addressed. The articles, which are grouped by species (poultry, ruminants, pigs, etc.) and by topic, deal with a wide range of arguments that, first of all, highlight the extraordinary complexity and diversity that exists in the animal production sector, and then, the great influence that nutrition and feeding can have in terms of optimizing the use of environmental resources and improving the welfare of farmed animals. In addition, all this is closely connected with the urgent need to safeguard the resources of the planet on which we live.

Download or read book Lactogenesis written by Monica Reynolds and published by University of Pennsylvania Press. This book was released on 2016-11-11 with total page 284 pages. Available in PDF, EPUB and Kindle. Book excerpt: Proceedings of a symposium, satellite to the 24th International Congress of Physiological Sciences, University of Pennsylvania.

Download or read book The Effect of Potassium and Fat in the Early Lactation on Milk Fatty Acids and the Nutrient Contributions and Biogas Potential of Co digestion of Feedstocks and Dairy Manure written by Guiling Ma and published by . This book was released on 2016 with total page 184 pages. Available in PDF, EPUB and Kindle. Book excerpt: This dissertation research focused on the areas of nutrition and nutrient management. Three experiments were conducted with lactating cows to evaluate nutritional strategies to improve the efficiency of milk fat production. A fourth study defined the nutrient contributions and biogas potential of co-digestion of feedstocks and dairy manure. In the first study, 1.74 % potassium was compared to 2.33 % potassium of diet dry matter (DM) to investigate changes in milk fat of lactating dairy cows due to potassium supplementation. Through the 21 days of potassium supplementation, milk fat concentration was significantly increased from 4.03 % to 4.27 %. The fat concentration increase was associated with an increase in C18:1 11 trans. In the second study, ruminally inert fat products of either calcium salts of fatty acid (CAFA) rich in C16:0 and C18:1, or saturated fatty acid (SFA) rich in C16:0 were fed to early lactation multiparious Holstein dairy cows. The CAFA diet increased lactation performance when fed beginning at 45 +/- 24 days in milk (DIM) , however, the SFA diet resulted in an increase in milk protein yield with cows when fed beginning at 73 +/- 41 DIM. In the third study, ruminally inert fat products of either CAFA rich in C16:0 and C18:1, or SFA rich in C16:0 and C18:0 were fed to multiparious dairy cows starting at 14 +/- 2 DIM. When cows were fed a low fat diet of 3.4 +/- 0.4 % (DM) ether extract, the SFA diet increased lactation performance before the peak of lactation and during negative energy status. Body condition score change, energy status between different rumen inert fat products, and feed efficiency of 3.5 % fat corrected milk/DMI was not different. Greater nutrient intake was partitioned into lactation performance with the CAFA diet from week 3 to 14 of lactation. The fourth study described the nutrient transformations and flow in an anaerobic digestion system and confirmed that biogas or methane yield could be accurately measured from the ratio of % volatile solids: % total solids.

Download or read book Air Emissions from Animal Feeding Operations written by National Research Council and published by National Academies Press. This book was released on 2003-04-07 with total page 286 pages. Available in PDF, EPUB and Kindle. Book excerpt: Air Emissions from Animal Feeding Operations: Current Knowledge, Future Needs discusses the need for the U.S. Environmental Protection Agency to implement a new method for estimating the amount of ammonia, nitrous oxide, methane, and other pollutants emitted from livestock and poultry farms, and for determining how these emissions are dispersed in the atmosphere. The committee calls for the EPA and the U.S. Department of Agriculture to establish a joint council to coordinate and oversee short - and long-term research to estimate emissions from animal feeding operations accurately and to develop mitigation strategies. Their recommendation was for the joint council to focus its efforts first on those pollutants that pose the greatest risk to the environment and public health.