Dairy Science Commons^™

Management And Investment: Two Pillars Of Automatic Milking Systems Efficiency, Abby N. Mccalmon

Masters Theses

Fetch cows, dairy cattle that do not voluntarily enter automated milking systems (AMS), increase labor costs, and decrease efficiency. The objective of this study was to describe fetch cows based on fetch lists and herd-management software data. This study was conducted on a commercial dairy farm (n = 510 cows) using 8 AMS from October 1, 2021, to May 10, 2022. Data were collected via PCDART, DairyComp, and a proprietary interface. Two fetch categories by cow, EverFetch (EF) and NeverFetch (NF), and three status groups by cow by day, True Fetch (on fetch list …

Staphylococcal Surface Proteins As Vaccine Candidates For The Control Of Staphylococcal Mastitis In Dairy Cows, Jessica Jean Vidlund

Masters Theses

Bovine mastitis, an inflammation of the mammary gland, is the single most costly disease of dairy cattle. Staphylococci, a major bacteria that cause bovine mastitis, are commonly divided into two major groups: Staphylococcus aureus and non-aureus staphylococci (NAS), previously known as coagulase-negative Staphylococcus species (CNS). Current mastitis control programs are not fully effective against staphylococcal mastitis and antibiotics are not sustainable due to limited success and the emergence of antimicrobial resistant bacteria. Non-antibiotic sustainable control tools, such as effective vaccines, are critically needed. Our lab developed and evaluated Staphylococcus aureus surface associated protein (SASP) and Staphylococcus chromogenes surface associated protein …

The Effect Of Bovine Endometrial Cell Conditioned Media On In Vitro Produced Bovine Embryo Development And Gene Expression, Mary A. Oliver

Masters Theses

In vitro produced (IVP) bovine embryos provide enhanced genetic value and a means for studying early embryonic development. However, IVP embryos are developmentally compromised and are lower quality compared to in vivo derived (IVD) embryos. Consequently, after transfer pregnancy rates from IVP embryos are consistently lower, as they exhibit the highest amounts of pregnancy failure during the early embryonic phase (prior to day 28). Progesterone (P4) has been shown to influence bovine endometrial epithelial (EPI) and stromal fibroblast (SF) cells to secrete developmentally important molecules that promote early embryo development and conceptus elongation. However, IVP embryos are not exposed to …

Relationship Of Observed Parlor Practices And Producer Attitudes With Bulk Tank Somatic Cell Counts In The Southeast Usa, Chandler Lauren Moats Blakely

Masters Theses

Inflammation of the mammary gland is indicated by a rise in somatic cell count (SCC) and impacts milk quality. The Southeast (SE) USA has a higher proportion of herds with elevated SCC compared to other USA regions. The SE also has the least information available about parlor procedures. The goals of this thesis are to explore the level of implementation of parlor procedures, determine which practices promote low SCC in Southeast USA dairy herds and investigate the association of attitude towards parlor management methods with BTSCC.

In chapter I, researchers performed on-farm assessments in Kentucky, Mississippi, Tennessee, and Virginia. The …

Effect Of Varying Rumen Degradable And Undegradable Protein On Milk Production And Nitrogen Efficiency In Lactating Dairy Cows Under Summer Conditions, Jeffrey D. Kaufman

Masters Theses

The objective is to determine the effect of reducing nitrogen input through feeding low rumen degradable protein (RDP) and rumen undegradable protein (RUP) proportions on milk production, nitrogen efficiency and metabolism in heat-stressed cows. Forty-eight mid-lactating, Holstein cows were assigned to treatments using a randomized block design in a 2x2 factorial arrangement of treatments (n = 12/treatment). Treatments included two levels of RDP (10 and 8%) and two levels of RUP (8 and 6%). From d 1 to 21, a common diet (10% RDP-8% RUP) was fed to cows followed with their respective treatment diets fed from d 22 to …

The Effect Of Heat Stress And Essential Amino Acids On Production And Metabolism Of Lactating Dairy Cattle, Kimberly Rose Kassube

Masters Theses

Heat stress (HS) causes decreases in production of lactating cattle that is only partially explained by decreases in intake. Evidence suggests that changes in energy and protein metabolism occur to cope with the impact of HS. The objective of this thesis was to determine if the effect of jugular infusion of essential amino acids (AA) ameliorated the negative effects of HS in milk production and metabolism. Twelve multiparous lactating Holstein cows were used in a crossover design to evaluate the effect of thermoneutral (THN) and HS environments along with the absence (CTL) …

Efficacy Of Extending The Voluntary Waiting Period In Lactating Dairy Cows To Improve Fertility Of Sex-Sorted Semen, Sarah E. Orr

Masters Theses

The objective of this study was to compare fertility of sex-sorted semen in lactating cows using a voluntary waiting period (VWP) of approximately 55 days (VWP55) or 85 days (VWP85). At 21 days in milk (DIM), cows were randomly assigned to begin estrus synchronization at 55 or 85 DIM. Only cows confirmed cyclic by 55 DIM were synchronized. At 55 or 85 DIM, cows [VWP55 (n=44); VWP85 (n=45)] having a corpus luteum (CL) were administered PGF_2α [two alpha]. Estrus was monitored continuously by the HeatWatch® [registered sign] system ( …

Effects Of Bedding With Recycled Sand On Lying Behaviors, Udder Hygiene, And Preferences Of Lactating Holstein Dairy Cows, Heather Deanna Ingle

Masters Theses

Effects of bedding with recycled sand and season on lying behaviors, stress, hygiene, and preferences of late-lactation Holstein cows were studied. Cows (n=64) were divided into 4 groups (n=8 per group) per season. In summer (Aug-Sept), cows were balanced by days in milk (268.1±11.9 d) and parity (2.0±0.2). In winter (Jan-Feb), mean DIM was 265.5±34.1 d. Cows were assigned to one of two treatments (trt) using a crossover design with each trt lasting 7-d (no-choice phase): bedding with recycled sand (RS; n=32) or control (CO; clean sand; n=32). Stocking density was maintained at 100%. Choice phase allowed a cow to …

Impact Of Matrix Metallopeptidase-9 Supplementation During In Vitro Maturation Of Bovine Oocytes, Megan Rene Goodwin

Masters Theses

Heat-induced decreases in bovine blastocyst development have been related to reductions in latent matrix metallopeptidase-9 (proMMP9) production from maturing cumulus-oocyte complexes. Elevated intrafollicular proMMP9 levels at the time of oocyte retrieval have been positively related to pregnancy following human IVF. Thus, we hypothesized that heat-induced reductions in proMMP9 levels during oocyte maturation may be responsible for decreased blastocyst development. As a first step towards testing this hypothesis, bovine cumulus-oocyte complexes were matured at 38.5°C for 24 h with 0 or 300 ng/mL recombinant human proMMP9 (rhMMP9) added at 0 h of in vitro maturation (hIVM). No differences were found in …

The Effect Of Bedding Surface And Muscid Fly Populations On The Welfare Of Pre Weaned Holstein And Jersey Calves, Christa Anne Kurman

Masters Theses

The first objective of this study was to determine the effect of bedding on the welfare of Holstein and Jersey calves housed using individual hutches bedded with gravel, rubber mats, or sand. A second objective was to determine the effects of stable and house fly populations on calf welfare. Bedding quality and fly management are aspects of improving animal welfare on dairy farms. It was hypothesized that sand or mat would increase lying time and decrease lying bouts, but not affect BW gain or feed intake in calves indicating that these bedding surfaces increased calf welfare. It was hypothesized that …

Bovine Mammary Interleukin-8 Receptor Expression And Genetic Association With Streptococcus Uberis Based Mastitis., Lydia Jean Siebert

Masters Theses

Mastitis is an economically distressing disease in the dairy industry. Bacterial pathogens enter the gland and encounter cell types that release immune mediators including interleukin (IL)-8. IL-8 has two membrane bound receptors: CXCR1 and CXCR2. CXCR1 and CXCR2 are expressed on neutrophils and other cell types in other species but their expression is unknown in the bovine mammary gland. To test this, mammary tissue samples from six Holstein dairy cows were subject to dual immunofluorescence with bovine specific CXCR1 and CXCR2 antibodies and cell type markers. CXCR1 was expressed on alveolar epithelial cells, fibroblasts, and leukocytes. CXCR2 expression was identified …

Hydrogeology Of The Little River Animal Agriculture Environmental Research Unit And Impacts Of Dairy Operations On Groundwater, Robert Wesley Hunter

Masters Theses

This thesis describes the development of an integrated hydrogeologic/hydrologic site assessment and groundwater/surface water quality monitoring program at the University of Tennessee – Little River Dairy Farm, located near Townsend, TN. Hydrologic/hydrogeologic investigations of streams and groundwater at the site have been underway for more than 5 years, and these are expected to provide background data for assessing impacts of dairy wastes. The lower half of the ~180 ha site consists of low-relief fields used for row crops, which are underlain by 4 – 9 m of alluvial deposits on top of black shale or limestone that include sinkhole features. …

Assessing Mitochondrial Activity In Embryos From Heat-Stressed Ova, Kimberly Ann Nagle

Masters Theses

Elevated ambient temperatures negatively impacts pregnancy rates in agriculturally important females. An oocyte undergoing meiotic maturation exposed to a physiologically-relevant heat stress results in alterations of developmentally important processes and reportedly decreases subsequent developmental potential after fertilization. To address problems of reduced competence after exposure to heat stress for the first 12 h of meiotic maturation (hIVM), Payton (2009) assessed the transcriptome profiles of oocytes and associated cumulus cells by microarray analysis and reported heat-induced perturbations at the molecular level in the oocyte. Specifically, 20 transcripts involved in mitochondrial function exhibited alterations in relative abundance of heat-stressed oocytes …

The Challenges Of Making A Blastocyst-Stage Embryo: Impact Of Heat Stress & Technical Factors Associated With Ivp Procedures, Estanislao Peixoto

Masters Theses

It was hypothesized that technical factors associated with in vitro production (IVP) of embryos may influence rate of blastocyst development of oocytes matured at 38.5 or 41.0 C. To test this hypothesis, a retrospective meta-analysis was performed. Simple linear regression was performed to analyze continuous variables and ANOVA for categorical variables. Interactions among factors and maturation temperature on blastocyst development were analyzed using dummy regression for continuous variables, and using a factorial treatment design and ANOVA for categorical variables. Month of collection was the only variable that impacted responsiveness of ova to heat stress. Independent of maturation temperature, variables that …

Sources Of Psychrophilic Bacteria In A Dairy Plant With An Emphasis On Air, Kotha Madhava Rao

Masters Theses

[From the Introduction]

The dairy industry generally recognizes that the psychrophilic bacteria are those bacteria which can grow in milk and milk by-products at refrigerated temperatures. Although psychrophiles have been recognized since the latter part of the last century, they were of relatively little importance in the dairy industry, as long as the milk and milk products were consumed within a reasonably short period of time after production or processing.

The presence of psychrophilic bacteria in milk has been attracting increasingly more wide spread attention since the early 1950's because of the introduction of bulk tanks on the …

Dairying In Spring Point Township, Cumberland County, Illinois, Robert G. Ferren

Masters Theses

No abstract provided.

Quantitative Study Of Growth Of Some Dairy Psychrophiles, Taher A. El-Farekh

Masters Theses

Summary and Conclusions:

Samples of pasteurized skim milk were steamed for 25 minutes at approximately 100° C. and inoculated with pure cultures of Pseudomonas fluorescens, A and B, at different levels, Pseudomonas fragi, Brevibacterium lipolyticum. The fifth culture was the normal flora of commercially pasteurized skim milk treated as a pure culture. All samples were stored at 4° C. Bacterial growth was determined using agar plates incubated at 25° C. for 3 days.

The generation time was calculated for all cultures which ranged from 5.55 hours for Pseudomonas fragi to 11.24 hours for Brevibacterium lipolyticum. The …

Bin-Cured Versus Field-Cured Alfalfa Hay For Dairy Heifers, Marshal C. Winton

Masters Theses

INTRODUCTION:

This study was undertaken for the purpose of comparing the nutritive value of bin-cured and field-cured alfalfa hay, using actual feeding trials with dairy heifers.

Any study involving the production and preservation of more and better hay has great economic importance. Shepherd and others (21), in discussing the losses of hay from a national standpoint, state that:

The uncertain weather conditions that frequently exist while hay is being made, particularly in the humid sections of the country, are responsible for variations in the quality of the hay and for large losses of nutrients during harvesting. Conservative estimates indicate that …