Dissertations / Theses on the topic 'Dairy'

A linear programming (LP) model has been developed (CAP-DAIRY) to describe the grass utilisation and feeding system on a dairy farm. It links several components of the system and optimizes the system as a whole. The model links a grass utilisation model, a feed ration model and a novel model which relates on-going milk yield to on-going feeding level. The main feature of the model is the approach adopted to relate feeding levels, milk yield and weight changes. When cows are fed more than they require for maintenance and the current level of milk yield, the excess energy becomes increased bodyweight and cause an increase in milk yield. When fed less than they require, they mobilize reserves into energy for milk production and lose weight and tend to reduce milk yield. At the start of the lactation some weight loss is tolerated. This is treated in the model as a requirements for up to 0.5 kg/day weight loss in addition to maintenance so that a lower weight loss is the increase case. A linear mathematical model that represents this mechanism was developed and incorporated into the LP and fitted to data which changed the level of feeding of dairy cows during the lactation. This gives a greater flexibility to the LP and allows the model to determine optimal feeding levels at all stages of the lactation and as a consequence optimal milk yields and optimal stages for weight changes, which vary depending on calving date and feed availability The grass utilisation model permits the successive utilisation of grass for grazing or silage making. Grazing can take place two, three or four weeks after the previous use and silage making five, six or seven weeks after the previous use. To allow for the effect of silage making on regrowth, use after this is delayed by one week. Data on energy and dry matter yields at any time is required and the model determines the optimum schedule of use and frequency. Silage is made in a number of separate silos but the feeding-out energy value makes the model non-linear. This is solved by using a recursive approach in which the initially unknown feeding value is calculated from successive solutions and the model reoptimized to convergence. The feed ration model determines the amount of grass, silage and concentrates required based on the maximum dry matter intake, which is a function of yield and the energy required for maintenance, milk yield and any weight change. The model could be easily extended to also use protein given suitable data. The LP determines the optimal land use for forage and cash crops, calving pattern and feeding strategy according to specific farm conditions such as farm area, milk quota and availability of forage maize. Several scenarios were studied and the effects of changes of different parameters analysed. Results indicated that net margins increased with maize crop areas and gave higher optimum milk yields replacing concentrates up to an optimum area of maize. The seasonality of milk prices affected particularly calving pattern and milk yield and the results suggested they led to more even milk production due to encouraging Autumn calving. Results also showed that the optimal feeding levels is different for cows calving in different periods of the year resulting in different weight change pattern and milk yields. Spring calving cows lost more weight than cows calving in any other period, but regained the weight lost quickly. They also produced the lowest level of milk. Autumns calving cows had the highest milk yield and the lowest weight losses, although a longer period to regain that weight was optimal. Summer calving cows produced slightly less milk and lost slightly more weight than Autumn cows. Another important aspect that results showed was the influence that maize silage has on farm decisions. The larger the maize crop area the higher the marginal price of milk quota, showing that milk quota constraint was more severe for those cases and consequently higher prices for extra milk quota could be paid. CAP-DAIRY is suitable for analysing the impact that changes such as milk prices, fertilizer prices or concentrates prices would cause on the optimal plans. The model is also helpful to evaluate research priorities by analysing the effects caused by biological and technical changes such as grass varieties and machinery.

The aim of this study was to determine how daily yield records might be used to improve the genetic evaluation of dairy cattle, which is currently based on 305-day yield predicted from monthly test day records. Daily milk yield records of 488 first lactation Holstein Friesian cows were obtained from one UK herd and summarised into weekly averages. Weekly fat, protein and lactose content records, from the same herd, were also obtained and each multiplied by test day yield to estimate fat, protein and lactose yields. Analysis of variance indicated that residual standard deviation (RSD) for each trait was lower when season of production was included in the model instead of the season of calving. The difference in RSD was more for fat and protein yields than the other traits. Lactation stage and season were the most important environmental factors affecting daily milk yield and composition while calving age had a small but significant (P<0.05) effect. Pregnancy accounted for 1.4 to 1.7% of the variation in yield traits but less than 0.4% of the variation in content traits. Its effects varied with gestation stage causing daily milk yield to decline by 3kg in the 8^th month of gestation. A significant interaction between lactation and gestation stage was observed which suggested that the negative effect of pregnancy was higher in mid than late stages of lactation. Standard models of the lactation curve studied accounted for a substantial proportion of the variation in daily milk yields of typical lactations, which made up about half of the lactations studied. The other half was made up of atypical lactations such as highly persistent animals with almost flat curves whose lactation could not be adequately modelled with the standard curve functions. A regression spline model was derived which was as good as the best 3 parameter model and more flexible. These results indicate that models which make rigid assumptions about the shape of the lactation curve may not be very effective in accounting for the effect of lactation stage on daily yields. Yields of the same trait at different stages of lactation were positively correlated throughout but the correlation between yield and content traits was negative. Average correlation between milk yield and adjacent weeks was 0.93 declining to 0.61 between yields 41 weeks apart. Daily milk yields in mid and late stages of lactation were more highly correlated with 305-day yield than yields in early lactation. Covariance functions, using orthogonal polynomials up to the order of 4, were used to model genetic and permanent environmental covariances in a restricted maximum likelihood (REML) random regression (RR) model. Genetic parameters and breeding values were estimated for yield in every week of lactation. There were compared with estimates from a multivariate model, which considered yield at different stages as different traits, and a repeatability model without random regressions.

Thesis (B.S.)--California Polytechnic State University, 2009.
Project advisor: Edwin Jaster. Title from PDF title page; viewed on Jan. 21, 2010. Includes bibliographical references. Also available on microfiche.

The main goal of this research was to explore the use of benchmarking in the dairy industry. This includes descriptions of the various sectors in North America where benchmarking has been used successfully on a continuous basis or in research. Benchmarking methods that are currently used in the Quebec dairy industry are examined. An improvement to such methods is proposed through the use of visualization, coupled with interactivity, and with a focus on adaptability and usage. The advantages of such an interactive tool are discussed in light of on-farm decision-making, and a further use of visual slider applications is described to help with parameters of known economic importance.

The vogue for installing dairies, often termed "fancy" or "polite" dairies, within the gardens of wealthy English estates arose during the latter half of the eighteenth century. These polite dairies were functional spaces in which aristocratic women engaged, to varying degrees, in bucolic tasks of skimming milk, churning and molding butter, and preparing creams. As dairy work became a mode of genteel activity, dairies were constructed and renovated in the stylish architectural modes of the day and expanded to serve as spaces of leisure and recreation. Dairies were often lavishly outfitted to create a delicate and clean atmosphere, a fancy yet functional space pleasing to elite tastes. Ornamental dairies were distinctive structures incorporated into the ideologically-laden landscape gardens of the elite. While pleasure dairies have received some scholarly insights, this study is the first to exclusively treat the fashion for pleasure dairies in terms of English culture and attitudes of the era. It explores the cultural iconology of the ornamental pleasure dairy in England and its appropriation into the landscape parks of the elite. Ornamental dairies held significant ideological associations that were heightened and nuanced by their placement within the larger symbolic space of the country estate and its garden park. Their ornate and decorative quality referenced their intentionality of being displayed and viewed. As objects within the English landscape, they were sites to be seen and from which to see"”not only the landscape beyond, but also ideologies about identity, class, gender and morality, key dialogues of eighteenth-century English culture. The dairy emerges as an intriguingly ambiguous space in which morality, innocence and sensuality can be celebrated simultaneously. This thesis explicates three different readings of the English dairy in the eighteenth-century cultural imagination. Dairies were structures whose contradictory fancy/functional nature referenced contemporary attitudes about the acceptable balance between industry and idleness among the gentility. The ornamental dairy was a space whose signification was employed by women to create an acceptable realm for productive yet pleasurable activity to counter stereotypes of idleness and decadence. As structures related to the dialogue of agricultural improvement and productivity when included on estates, these dairies held signification of industry and social beneficence for gentlemen as well. Placed within a class landscape, the virtue of the dairy space came to represent the identity of the aristocracy, as well as England itself. Its class allusions notwithstanding, the dairy remained a highly feminine space. Accepted attitudes about dairy labor created a gendered site whose activities and aesthetics referenced contemporary dialogues about the nature of women"”biologically, emotionally and physically. As such, these dairies and their decorative accoutrements were metaphors for the elite women who worked within. They were social constructions of femininity and the expectations and ideologies regarding women's "natural" roles and reproductive responsibilities as mothers in society. Within a male-produced and governed landscape garden, dairies were venues in which cultural notions of propriety were enforced during a time when the roles of women were demanding reconsideration. However, even the gendered nature of the dairy had its dual significations. The ornamental dairy was a liminal space, a ritual realm that asserted female power and sexuality, as well as ideas of sanctity and chastity. The native femininity and its legacy as an intuitively feminine task also created an exclusive female space that resisted the male gaze, thus creating a dangerous space, an ambiguous space that operated outside the social norms of the time. This mystique of the dairy and its cultish practices was amplified when dairies were placed as independent structures in romantic and idyllic landscape parks. This liminal dairy realm was part of a landscape garden that was equally conflated as a site of liminality and ritual. The idealization and ornamentation of dairies within the garden space enhanced their imaginative distinction and allowed them to become spaces that were both sacred and sexual, pious and pagan. The dairy became an acceptable realm in which to enact varied notions of femininity and sexuality.

A genetic approach to lowering protease (plasmin) levels in milk, requires the presence of polymorphism of bovine plasminogen. This study was conducted to determine to what extent genetic polymorphism exists in dairy cattle. Bovine plasminogen was first purified from Holstein cow plasma by affinity chromatography on Lysine-Sepharose and antibodies to bovine plasminogen were raised by monthly intramuscular injection of the isolated bovine plasminogen into rabbits. For plasminogen phenotyping, blood samples were collected at random from 50 Holstein and Ayrshire cattle, and plasminogen was isolated from the plasma using lysine-Sepharose and then treated with neuraminidase. After separation by isoelectric focusing (pH 3.5-9.5) in polyacrylamide gels, Plasminogen polymorphs were detected immunologically using rabbit anti-bovine plasminogen antibodies. Additionally, the plasminogen isoforms were evaluated with a functional assay (caseinolytic overlay technique) after activation of the plasminogen with urokinase. Six plasminogen phenotypes were identified which represent products of 5 variant alleles. The 5 plasminogen variants were characterized based on their isoelectric points and designated PLG A$ sb2$ (pI 6.5 and 7.0), B$ sb2$ (pI 7.6 and 7.8), C$ sb1$ (pI 6.8), D$ sb2$ (pI 7.8 and 8.0), and E$ sb2$ (pI 6.8 and 7.0). PLG A$ sb2$ and PLG B$ sb2$ were the most common variants in these cattle. The 6 phenotypes were $ rm A sb2A sb2, B sb2B sb2, A sb2B sb2, B sb2C sb1, A sb2D sb2 and D sb2E sb2$. The phenotypic frequencies in Holstein and Ayrshire were very different, $ rm A sb2A sb2 and B sb2B sb2$ being respectively the most frequent phenotype. In addition, DNA polymorphism at bovine plasminogen gene was detected when genomic DNA was digested with the restriction enzyme Msp I and hybridized with mouse plasminogen cDNA. This is the first description of plasminogen polymorphism reported in dairy cattle. If different variants have altered activity, the detrimental effect

Master of Agribusiness
Department of Agricultural Economics
Kevin Dhuyvetter
The size of our dairy operation increased from 300 milk cows to 1,700 milk cows in 2003. Once the dairy operation increased, the dependency on milk price to support the entire operation also increased. This was due to the fact that the cropping side of the operation became more devoted to growing feed for the livestock as opposed to producing cash crops. Thus, the increase in the number of milk cows led to decreased diversity in our income potentially increasing the financial risk of the operation. The purpose of this thesis is to study different risk management tools and strategies to aid in the formulation of a risk management plan for milk sales in our operation. Risk management strategies using forward contracts, futures, put options, and cash were analyzed at different time periods and various minimum price levels. The strategies were analyzed over the last ten years (2001-2010) of available price data. Twenty-five risk management strategies were analyzed both with and without set minimum milk prices. Minimum price levels ranged from $14/cwt to $17/cwt in $1 increments. The time frame for the transaction ranged from zero to twelve months prior to production in three-month increments. Based on historical data, risk management strategies can be used to decrease the price risk faced by an operation. The risk management strategies did not affect the average price received at statistically significant levels typically considered. Different risk management opportunities are highlighted that need to be analyzed before fully implementing a risk management plan for dairy operations.

Thesis (B.S.)--California Polytechnic State University, 2009.
Project advisor: Leanne Berning. Title from PDF title page; viewed on Jan. 21, 2010. Includes bibliographical references. Also available on microfiche.

Thesis (B.S.)--California Polytechnic State University, 2009.
Project advisor: Edwin Jaster. Title from PDF title page; viewed on Jan. 21, 2010. Includes bibliographical references. Also available on microfiche.

Thesis (B.S.)--California Polytechnic State University, 2009.
Project advisor: Leanne Berning. Title from PDF title page; viewed on Jan. 21, 2010. Includes bibliographical references. Also available on microfiche.

Mycoplasmosis is endemic to most countries where dairy production occurs. This thesis focuses on observations in Mycoplasma bovis-infected herds associated with bulls, reproduction, subclinical carrier animals and M. bovis exposed calves. Mycoplasma bovis was isolated from four of 118 bulls after use in four herds infected with M. bovis. This study demonstrated a high degree of subclinical exposure of bulls to M. bovis in infected herds via serology and highlighted the potential for bulls to be mycoplasma carriers within and between herds. Mycoplasma spp. were infrequently isolated from vaginas of cows pre- (1.9%; 12/629) and post-bull (3.2%; 20/629) exposure. Mycoplasma bovis was isolated from one cow only. There was no evidence of venereal transmission of M. bovis in cows in M. bovis-infected herds that use natural service bulls. Apparent prevalences of subclinical M. bovis intramammary infection were low within four herds immediately following outbreaks of clinical M. bovis disease. Therefore, considering the high expense associated with individual animal milk sample collection and testing, the return on diagnostic investment was very limited. From 16 cows with clinical M. bovis mastitis, M. bovis was isolated from the vagina of only three cows and was not detected from the noses or eyes of any cows. It is very likely that sampling these sites would be ineffective for detecting subclinical infection in cattle. Despite a high M. bovis ELISA seroprevalence at weaning in a two-year longitudinal study of M. bovis-exposed replacement heifers, M. bovis was isolated infrequently. A single heifer was repeatedly detected with M. bovis, demonstrating the rare possibility of a long-term M. bovis carrier state in replacement heifers. The research presented in this thesis has contributed new knowledge towards the control of M. bovis associated disease and highlighted risk areas for consideration when developing biosecurity measures to prevent M. bovis introduction to a herd.

Crossbreeding is a common practice in poultry and swine breeding. Conversely, this mating system has not been widely adopted for breeding purposes in dairy cattle in temperate climates (except in New Zealand), mostly because of the superiority of Holsteins for milk yield, the economic relevance of this trait, the strong historical influence of purebred breeders and breed associations, and some biological aspects such as the low reproductive rate and the long generation interval of the cattle species. Recently, the interest in crossbreeding aspects has been growing among dairy producers, and this practice may be used to remove inbreeding depression accumulated in the major dairy breeds, to improve some economically important traits such as fertility, health, longevity, and calving ease, and to increase economic gains in countries where milk pricing systems have put a great emphasis on milk solids. It appears important to estimate the expected level of heterosis for traits of economic interest in dairy cattle in order to evaluate the profitability of crossbreeding. Objectives of this work were a) to estimate crossbreeding effects for milk yield traits and calving interval in dairy cows (Chapter 2), b) to investigate the influence of the environment on the expression of heterosis for milk yield traits, somatic cell score, and age at first calving in dairy cattle (Chapter 3), and c) to estimate the effect of different genotypes on age, live weight, price, and commercial value of purebred and crossbred calves sold for beef and veal production (Chapter 4). The thesis started with an introduction on crossbreeding in dairy cows (Chapter 1), followed by three contributions. Chapter 2 provided a study to assess crossbreeding effects for lactation milk, fat, and protein yield, and calving interval in dairy cows reared in Ireland. The analysis showed that breed effects for production traits were in favour of North American Holstein Friesian cows, while for calving interval were in favour of Friesian, Jersey, and Montbéliarde breeds. The highest heterosis estimates for milk yield traits were for crosses between North American Holstein Friesian and Jersey, with first generation cows giving 626 kg more milk, 25 kg more fat and 21 kg more protein than the average of the pure parental breeds. Regarding calving interval, the highest estimate was for crosses between North American Holstein Friesian and Montbéliarde, with first generation cows showing 10 d less calving interval than the average of the parental breeds. Estimates obtained in this study could be considered in the genetic evaluation model currently run in Ireland. Chapter 3 investigated the effect of the environmental level of production on the expression of heterosis for lactation milk, fat, protein, and fat plus protein yield, somatic cell score and age at first calving in primiparous Black and White dairy cows reared in The Netherlands. Holstein Friesian, Dutch Friesian and first generation crosses obtained from the mating of these strains were studied. The environments (low, medium, high) were defined on the basis of the herd production level. Holstein Friesian produced more than Dutch Friesian. First generation crosses showed comparable productions to Holstein Friesian, especially in the low environment. Estimates of heterosis for production traits ranged between 2.4% for milk yield in the high environment and 5.3% for fat yield in the low environment, with decreasing percentages observed for the traits when moving from the low to the high environment. Overall, heterosis for somatic cell score and age at first calving were moderate. Results emphasized that the highest non-additive genetic effects for yield traits were expressed in the most stressful environment, i.e. low level of production. Chapter 4 investigated the effect of four purebred genotypes (Brown Swiss and Holstein Friesian as dairy breeds, and Simmental and Alpine Grey as dual purpose breeds), and eight crossbred genotypes derived from mating of previous four dam breeds and two sire breeds (Limousin and Belgian Blue) on age (d), live weight (kg), price (Euro/kg), and market value (Euro/calf) of calves sold for veal and beef production during public auctions. Dual purpose purebred calves were heavier and presented higher price and market value than dairy purebreds (314 and 227 Euro/calf for Simmental and Alpine Grey, and 189 and 203 Euro/calf for Brown Swiss and Holstein Friesian, respectively). Crossbreeding with Limousin bulls increased live weight, price, and market value of calves from dairy and Alpine Grey cows, but had a small influence on price and market value of calves from Simmental cows. Crossbreeding with Belgian Blue bulls increased price and market value of calves much more than Limousin, particularly when used on Brown Swiss and Alpine Grey.
L’incrocio è il sistema riproduttivo di riferimento delle produzioni avicole e della maggior parte di quelle suinicole. In queste specie l’eterosi è un bonus utile e largamente sfruttato per migliorare la produttività e l’efficienza produttiva degli animali. Al contrario, nei climi temperati gli allevatori di vacche da latte tradizionalmente hanno escluso l’incrocio dalla gestione riproduttiva della loro mandria (produzione della rimonta). L’unica eccezione è rappresentata dalla Nuova Zelanda. I motivi alla base di questa esclusione sono la superiorità della razza Holstein per la produzione di latte, l’importanza economica assunta da questo carattere in molte realtà produttive, la forte influenza esercitata delle associazioni di razza a livello mondiale e alcune considerazioni di carattere biologico come la bassa efficienza riproduttiva e l’intervallo di generazione piuttosto lungo nella specie bovina. Tuttavia, il panorama zootecnico è in continua evoluzione e negli ultimi anni si è assistito ad un crescente interesse da parte degli allevatori nei confronti della possibilità di implementare l’incrocio in allevamento. Tale sistema riproduttivo può essere utilizzato per rimuovere gli effetti negativi della depressione da consanguineità che, nelle maggiori razze da latte, ha agito su diversi caratteri di interesse economico; l’accumulo di omozigosi e la conseguente depressione da consanguineità sono il frutto della forte pressione selettiva esercitata entro le razze pure. Inoltre, l’incrocio può costituire un valido strumento per il miglioramento dei caratteri funzionali a bassa ereditabilità tra cui la fertilità, il fitness, la longevità e la facilità di parto. Infine, può costituire un modo per migliorare la qualità del latte in termini di proteina e grasso in quelle realtà dove i costituenti del latte vengono premiati dai sistemi di pagamento vigenti. La valutazione della redditività di un programma di incrocio deve essere preceduta dalla stima dei livelli di eterosi per i caratteri economicamente rilevanti nelle bovine da latte. Gli obiettivi della presente tesi sono stati a) stimare gli effetti dell’incrocio per i caratteri produttivi e per l’interparto in vacche da latte (Capitolo 2), b) investigare l’influenza esercitata dall’ambiente sull’espressione dell’eterosi per caratteri produttivi, cellule somatiche ed età al primo parto in vacche da latte (Capitolo 3) e c) stimare l’effetto di diversi genotipi sull’età, il peso vivo, il prezzo ed il valore commerciale di vitelli puri e meticci venduti per la produzione di vitellone e vitello a carne bianca (Capitolo 4). La tesi inizia con un’introduzione sull’incrocio nel settore bovino da latte (Capitolo 1), seguita da tre contributi sperimentali. Nel Capitolo 2 sono stati stimati gli effetti dell’incrocio sulla produzione di latte, grasso e proteina, e sull’interparto in bovine da latte allevate in Irlanda. L’analisi ha evidenziato che gli effetti razza per i caratteri produttivi sono stati in favore della razza Holstein, mentre per l’interparto sono stati in favore delle razze Frisona, Jersey e Montbèliarde. Le stime più alte di eterosi per latte, grasso e proteina si sono avute nei meticci Holstein x Jersey: gli incroci di prima generazione hanno prodotto 626 kg di latte, 25 kg di grasso e 21 kg di proteina in più a lattazione rispetto alla media delle razze parentali pure. Per quanto concerne l’interparto, la stima più alta si è avuta nei meticci Holstein x Montbéliarde: gli incroci di prima generazione hanno evidenziato una contrazione di 10 giorni di interparto rispetto alla media delle razze parentali pure. Le stime ottenute in questo studio potrebbero essere considerate nel modello di valutazione genetica attualmente utilizzato in Irlanda. Nel Capitolo 3 è stato investigato l’effetto dell’ambiente (livello produttivo) sull’espressione dell’eterosi per la produzione di latte, grasso, proteina e materia utile (grasso più proteina), punteggio di cellule somatiche ed età al primo parto in bovine primipare Pezzate Nere allevate in Olanda. I genotipi presi in esame sono stati la Holstein, la Frisona Olandese e gli incroci di prima generazione tra queste due linee. Gli ambienti sono stati suddivisi in bassi, medi e alti sulla base del livello produttivo degli allevamenti. La Holstein ha manifestato produzioni più elevate rispetto a quelle della Frisona Olandese. Gli incroci di prima generazione hanno evidenziato produzioni simili a quelle della Holstein, soprattutto nell’ambiente basso. Le stime di eterosi sono risultate comprese tra il 2,4% per la produzione di latte nell’ambiente alto ed il 5,3% per la produzione di grasso nell’ambiente basso. Si sono osservate percentuali di eterosi decrescenti per latte, grasso, proteina e materia utile passando dall’ambiente basso a quello alto. Complessivamente, i livelli di eterosi per le cellule somatiche e l’età al primo parto sono risultati moderati. I risultati hanno messo in evidenza che gli effetti genetici non additivi per i caratteri legati alla produzione si sono espressi maggiormente nell’ambiente più stressante per tali caratteri, cioè quello basso. Nel Capitolo 4 è stato analizzato l’effetto del genotipo sull’età (giorni), il peso vivo (kg), il prezzo (Euro/kg) ed il valore commerciale (Euro/vitello) di vitelli venduti nel corso di aste pubbliche e destinati alla produzione di vitellone e vitello a carne bianca. I genotipi puri erano rappresentati da due razze da latte (Brown Swiss e Holstein) e da due razze a duplice attitudine (Simmental e Grigia Alpina), mentre i genotipi meticci erano di otto tipi diversi e sono stati ottenuti dall’accoppiamento delle precedenti quattro razze materne con due razze paterne (Limousin e Bianca Blu del Belgio). I vitelli puri figli di razze a duplice attitudine sono risultati più pesanti e hanno evidenziato un prezzo ed un valore commerciale più elevati rispetto a quelli dei vitelli puri di razze da latte (314 e 227 Euro/vitello rispettivamente per Simmental e Grigia Alpina e 189 e 203 Euro/vitello rispettivamente per Brown Swiss e Holstein). L’incrocio con tori Limousin ha incrementato il peso vivo, il prezzo ed il valore commerciale dei vitelli figli di vacche da latte e della Grigia Alpina, ma ha avuto una modesta influenza sui vitelli figli di vacche Simmental. L’incrocio con tori di razza Bianca Blu del Belgio ha incrementato prezzo e valore commerciale dei vitelli molto più di quanto non abbia fatto la razza Limousin, soprattutto quando la prima è stata utilizzata sulla Brown Swiss e sulla Grigia Alpina.

Osteoporosis is a debilitating disease that afflicts an estimated 25 million Americans, especially women. Suboptimal intakes of calcium, phosphorus, and vitamin D contribute to development of osteoporosis. Results from the Third National Health and Nutrition Examination Survey (NHANES III) indicate that adult women do not meet the Recommended Dietary Allowance (RDA) for calcium. Results from other national studies indicate that adult women consume less than the recommended number of servings of dairy foods per day. Focus groups were conducted in rural and urban areas of Virginia to gain insight into middle aged women's perceptions of dairy foods. Four focus groups were conducted with a total of 39 women. The majority of the women were between the ages of 35 to 50 years; all were non-Hispanic white women. All had a minimum of a high school education, and the majority had some education beyond high school. Discussion questions addressed preferences for dairy foods, advantages and disadvantages of dairy foods, factors that influence dairy food choices, and possibilities for product improvements. Focus group discussions were audio taped and transcribed by the moderator. The moderator identified major and minor themes; women's responses were organized thematically. Results were reported in the following broad theme categories: perceptions of health and nutrition that influenced dairy food choices and factors that influenced dairy food choices. The predominant negative perception of dairy foods was that dairy foods were high in fat. Women also negatively associated dairy foods with lactose intolerance and kidney stones. The predominant positive perception of dairy foods was that dairy foods were a good source of calcium. Women also believed dairy foods were a good source of vitamins, although they were unsure of specific vitamins found in dairy foods. Participants were aware of osteoporosis, but many were not knowledgeable about risk factors or prevention related to osteoporosis. Many women used calcium supplements or vitamin-mineral supplements to help meet dietary calcium requirements. Results indicate a need for education on the role of dairy foods in osteoporosis prevention. Women's preferences for dairy foods influenced dairy food choices. Product characteristics, such as sensory attributes, convenience, cost, availability, and packaging, were mentioned as factors that greatly influenced dairy food choices. The majority of women stated that other household members influenced dairy food choices. Women also mentioned that physicians and media sources, such as magazine advertisements and television commercials, influenced their dairy food choices. Nutrition education for this population should continue to promote the view that "all foods can fit" into a healthy eating pattern. Nutrition education should be geared toward the fast paced lifestyle these women lead. Product development should focus on convenience items.
Master of Science

Inspired by the sudden recent incline in and awareness of veganism as well as my own personal involvement in such matters, I sought out to complete an empirical analysis to study the impact of consumer preferences. Originally intrigued by the consumption of meat and its impact on developing countries, I opted for a related topic with better accompanying data. Consumer preferences change regularly with an increasing plethora of reasons behind their decisions. As the guiding force of the demand side of the market, it was vital to study the impact of their choices. My decision to use plant-based milk was meant to be a proxy for consumers who could not consume dairy. To my surprise, the force behind the increase in plant-based milk consumption was not propelled by those with alternative lifestyles but regular consumers who wanted healthier and better-tasting options. Further analysis has led me to look past consumers themselves and their individual choices to identify the impacts of their choices. This required an intricate look into the United States dairy industry and its composition. What is recorded within the next 45 pages is a delicate web of outcomes spun by the needs of consumers. It branches out into the lives of small dairy farmers who cannot compete with larger farms. It spins out to form a massive web of increasing profit for the plant-based milk industry. It creates a loss in the whole milk sector of the dairy industry only to be filled by the organic and specialty sectors. While they can be guided into choices through various forms of advertisement, the world has changed since the introduction of modern economics, and consumers are learning to utilize the products that fit their lifestyles. Gone are the days of passive consumption and food pyramids. Information has never been as readily available as it is today, with the help of the internet and independent researchers, and consumers have chosen to use this to their advantage.

The aim of this Ph.D. work was to investigate the physiological role and the technological relevance of the urease activity of the dairy bacterium Streptococcus thermophilus. It has been achieved a deeper comprehension of this peculiar enzymatic activity following different approaches. A milk-based medium that allows the discrimination between urease-positive S. thermophilus strains and urease-negative ones based on the colonies morphology had been developed; it was used as screening method looking for urease-defective mutants after UV mutagenesis of urease-positive strains of industrial interest. Moreover, a cytofluorimetric protocol for the evaluation of urease activity of various samples containing S. thermophilus was developed: the proposed applications are related to the evaluation of the urease activity of starter culture biomasses of S. thermophilus and to the enumeration of the S. thermophilus population in probiotic products containing this species, among others. We propose that the cytofluorimetric method should be seen as an innovative tool to put besides the standard ones to evaluate the quality of the products previously mentioned. The investigation of the physiological role of urease of S. thermophilus cells growing in milk highlighted that in presence of this enzymatic activity the overall metabolism of the species is boosted. Moreover, the cooperative role of urease, previously described for the yogurt consortium, has been extended also to the cooperation between a urease-positive S. thermophilus strain and a urease-negative one, supporting the proposal of the urease activity as an altruistic cooperative trait, which is costly for urease-positive species but provides a local benefit to the urease-negative species sharing the same environment, which can take advantage of the release of ammonia. At industrial level, urease activity is still considered more for its detrimental effects than for the positive effects exerted on S. thermophilus: we proposed different strategies to overcome this industrial problem. Firstly, we produced mutants of urease-positive strains of industrial interest, but they showed lower acidification rate compared to their wild types. So, we proposed to modify the production process of the biomasses with the aim of obtaining cells which carry a lower urease activity compared to those currently produced. In conclusion, the present work gives new insight in the comprehension of the urease activity of the dairy bacterium S. thermophilus, on how it can be exploited to improve the acidification performances of the strains and how it cannot, so far, be controlled during the milk acidification processes.

The rapid expansion of China’s dairy herd in recent years, with a primary objective of increasing milk production, has given rise to speculation on the potential beef production from this Chinese black and white herd. This study examines whether or not economic incentives exist for dairy and beef producers in China to adopt dairy—beef production and the impact of dairy-beef production on Chinese beef supply, demand and international trade.

Thesis (M.S.)--Michigan State University. Dept. of Agricultural, Food, and Resource Economics, 2008.
Title from PDF t.p. (viewed on July 28, 2009) Includes bibliographical references (p. 105-108). Also issued in print.

Two lactation trials were used to investigate corn grazing as a management tool for dairies. Control (n = 18) cows, housed in free-stall barns were allowed ad libitum access to TMR while Grazing (n = 18 to 36) cows were limit-fed TMR down to 70% of that in Controls and allowed 24-h access to corn plots. By wk 3, Grazing cows consumed 7.9 +/- 1.5 kg/hd/d of standing corn. By wk 7, the crop had matured and Grazing cows consumed 11.42 kg/hd/d of corn grain. Intake of TMR by Controls was 20.07 +/- 0.46 kg DM/hd/d, 19.78% greater than Grazing groups. Corn grazing had no impact on body weight, condition score, or ruminal pH, but significantly increased milk production in the Grazing group. Corn grazing reduced the need for purchased commodities, while improving milk production and performance. The value of saved commodities and increased milk production was $0.71 per cow/d.

The primary objective of this thesis is to evaluate the interaction of milk protein/polyphenolic complexes and phospholipid membranes. Milk-proteins (casein, whey protein concentrate- WPC or milk protein concentrate-MPC) and polyphenols were either introduced when the liposomes were fabricated or mixed with preformed liposomes. A third combination was also used where polyphenol was incorporated into liposomes and milk proteins were mixed. The challenge of incorporating plant polyphenols into dairy foods is to retain their antioxidant activities. These polyphenols inhibit lipid oxidation in cellular membrane surfaces, although the mechanism of this inhibition is not entirely clear. There is significance of having them together. Polyphenols have significant binding affinity to proteins, which can lead to the formation of soluble and insoluble protein-polyphenol complexes. In the case of the milk proteins, such as casein, whey protein concentrate and milk protein concentrate, of interest here the capacity of inhibition of lipid oxidation in the membrane is significantly enhanced for the polyphenols in the presence of the proteins as assessed by lipid peroxidation inhibition capacity assays (LPIC). Thus the antioxidant action appears to involve these protein/polyphenol complexes, as well as direct antioxidant action by the polyphenol and some milk proteins. But it is not clear whether the interaction between the protein and the antioxidant is located on or near the membrane surface, or whether complexes are dispersed in bulk solution generally. However, the protection occurs for the phospholipids in the membrane in either case. Using small angle X-ray scattering (SAXS) allowed the nature and structure of the three-way interactions to be measured, depending on the interaction conditions, which have been chosen based on functional assays. These screening measurements formed the basis for neutron measurements - small angle neutron scattering (SANS). Polyphenolic antioxidants interact strongly with phospholipid membranes, causing perturbation of the lipid organisation, while their antioxidative ability is enhanced in the presence of milk proteins. The antioxidant perturbs the phospholipid packing, and that its primary location appears to be near the tail/head groups' interface of the phospholipids. With the increase in concentration, polyphenolic molecules travelled towards the inner part of bilayer. In such a position, and lacking electrostatic interactions, the interaction with water-soluble proteins is expected to occur through protein binding to the membrane surface. This knowledge of the nature and location of the protein/antioxidant interactions will shed light on the mechanism of the antioxidant ability and augmentation in these systems, which may be related to the development of functional food systems.

Variation in animal personality, in other words, behavioural responses consistent within individuals over time and/or across contexts, is predicted to be related to life-history traits, such as growth rate and investment in reproduction. How this translates into relationships between personality and milk production in dairy cows is however scarcely investigated and previous studies are showing contradicting results. To further investigate this relationship, individual consistencies in behaviour were related to milk production in two breeds of dairy cows (Swedish red and white cattle, SRB, and Holstein). Variation was found among the breeds in consistency of behaviours and both SRB and Holstein cows were highly consistent over time in stepping behaviour during milking and frequency of performed abnormal behaviours in home pen. Overall were Holstein cows consistent in more observed behaviours than SRB. Variation in neophobia and responses to social separation were more flexible, both among breeds and over time. Nevertheless, behaviour showed limited relationship with milk production. To conclude, the tests here carried out are useful in describing personality in cows; however, personality showed no relationship with milk production, encouraging future studies to explore this expected relationship further in other breeds and species.

Four visits were made to 50 dairy farms in England and Wales between February 2003 and February 2004 and a further three visits to 42 of these farms between February 2005 and February 2006. At each visit the locomotion of all cows was scored (15,597 cows, 34,643 measures). Multivariable regression analyses were preformed to identify risk factors associated with increased lameness (poor locomotion). Factors associated with mean herd poor locomotion were dry cows kept in straw yards compared with cubicle houses, pregnant heifers kept with milking cows compared with dry cows in winter, passage way widths <3m compared with 2:,3m, a kerb height of ~15cm compared with >15cm, routine trimming of claws ofall cows by a claw trimmer or by- the farmer compared with no routine claw trimming, feeding maize silage to milking cows compared with other forage types, and the use of automatic scrapers compared with tractor scrapers in the cubicle house. Farmers recorded the lesions they observed while treating lame cows. Sole ulcer, white line disease and digital dermatitis were the three most frequently recorded lesions. The occurrence of sole ulcer, white line disease or digital dermatitis compared with having no lesion was used as the outcome variable in three multilevel binomial logistic regression models with month from calving nested within cow nested within farm. Risk factors associated with increased risk of sole ulcer were being housed on sparse bedding for four months or more, having grooved concrete floors on ~e farm, large herd sizes and parity numbers of four and above. Risk factors associated with increased white line disease were grooved concrete floors increasing parity number. Risk factors associated with increased digital dermatitis were grooved concrete floors and large herd sizes. A large clinical trial was used to assess the effect of intervening on known risk factors associated with lameness. Farmers in the treatment group received farm specific recommendations grouped under five targets areas which reflected the hypothesised aetiologies of sole ulcer, white line disease and digital dermatitis. There were small reductions in locomotion score and sole ulcer rate on treatment farms compared with control. These suggested that the hypotheses that reduced standing time and encouraged increased lying time through improved cow comfort may reduce sole ulcer were, at least in part, correct. There was no clear effect of treatment on the rate white line disease and digital dermatitis. It is likely that more than one of the following factors explain the lack of significant results from these initial investigations; poor recognition oflameness by farmers, insufficient uptake of recommendations, predisposition to lameness from previous lameness event and insufficiently specific lesion definitions.

In commercial dairy cattle farming, stressful disease conditions, such as high somatic cell count (SCC), poor body condition score (BCS) or lameness, are associated with subfertility. The objective of this thesis is to identify key areas in the reproductive cycle associated with each condition which contribute to this subfertility. Cows 30-80 days post partum from two commercial dairy farms were scored for SCC, BCS and lameness over a 5 week period prior to the implementation of an oestrous synchronization programme. Blood and milk sampling, trans-rectal ultrasonography and oestrus behaviour monitoring were conducted. Follicular development from emergence to deviation was unaffected as all cows produced a dominant follicle, which continued to grow beyond lOmm. In the following period, mean follicular growth, maximum follicular diameter and time to ovulation were not influenced by any of the 3 conditions (p> 0.05). In the animals that ovulated (irrespective of clinical status), follicles grew faster and achieved a greater diameter than in the animals that failed to ovulate (p< 0.05). Fewer lame animals ovulated compared to healthy animals (p< 0.05) and fewer high SCC animals with concurrent lameness ovulated than cows with only high SCC (p< 0.05) In cows with high SCC, progesterone concentrations prior to PG injection, over the peri-ovulatory period, on Days 5 and 7 or during the mid luteal phase after ovulation were unaffected, as was mean oestradiol concentration prior to ovulation. In the cows that ovulated, the dominant follicle grew at the same rate and ovulated at a similar size and at the same time regardless of high SCC, lameness or both. High SCC cows tended to (p< 0.07) and lame cows did express an oestrus of lower intensity and had a lower maximum intensity score than healthy animals (p< 0.05). High SCC cows started displaying oestrus signs and stood to be mounted (STBM) later than their healthy counterparts (p< 0.05) while lame animals displayed oestrus and STBM earlier than non lame cows (p< 0.05).

Dairy farmers suffered substantially increased energy bills during the 1970's, at a time of herd expansion and modernisation of equipment to allow bulk milk refrigeration and storage on the farm. Little was known of the levels of electricity use in the dairy farming sector, but extrapolations had suggested a figure of 300 to over 400 kWh/cow/annum. Farmers were requesting quantitative estimates for the potential of conservation equipment, particularly plate heat exchangers and heat recovery units. An energy audit of dairy farms in South Devon is described. Over a period of two years, data were collected relating to energy use by each of the major components of a milking parlour and dairy, for a range of parlour sizes, levels of production and the ambient conditions. Analysis revealed the factors most influencing variations in energy use. An equation was developed to describe the energy use by a bulk milk tank, given the level of production and the ambient temperature. The bulk tank accounted for some 40% of the total energy used. The bulk tank has been studied in detail. The stages of heat transfer from the milk to the chilled water and the resulting effects upon the ice bank have been modelled. Laboratory investigations were carried out to determine some parameters empirically. The model's limits, sensitivity and validation are reported. Typical levels and ranges of energy use are suggested. A mean of approximately 250 kWh/cow/annum resulted from the audit, but 200 kWh/cow/annum was achieved by the most economical of farms without resort to conservation equipment, and this level is proposed as a target for the conscientious farmer. The factors affecting energy use in the farm dairy are identified as political, environmental, technical and managerial and these are discussed. The farmer's influence has to be directed mainly at the last of these categories. Investment in energy conservation equipment should not be considered until consumption is down to the proposed target level.