Lameness is a painful disorder that decreases performance and is highly recognized as one of the most important health and welfare concerns for dairy cattle. Visual gait scoring is the most common way to detect gait change in dairy cattle. However, this is not only subjective, but is also time consuming and costly. A need to remove the subjective assessment of human observation exists. Therefore, automatic gait change detection for continuous monitoring by precision dairy monitoring technologies may be beneficial. The first objective of this research was to characterize behavior and production variables as cow gait changed to evaluate potential usefulness in gait change detection across two different studies. Weighted gait score was a significant (P < 0.05) predictor of rumination time for study 1. Rumination time decreased as weighted gait score increased. However, for study 2, numbers of steps and feeding time were significant predictors (P < 0.05). Number of steps increased as weighted gait score increased. Time at the feedbunk and feedbunk visits decreased as cows weighted gait score increased. The second objective was to compare behavior and production variables for each individual gait aspect in increasing gait scores to evaluate potential usefulness in gait change detection across two different studies. For study 1, milk yield, rumination, and neck activity decreased as cows as tracking score increased. For study 2, lying time decreased as cow’s general symmetry score increased. Feedbunk visits decreased as cows tracking score increased. Number of steps increased as cow’s spine curvature score increased. Time active increased as cows head bobbing score increased. Activity increased as cows speed score increased. Lying time decreased as cow’s abduction/adduction score increased. The third objective was to detect gait change utilizing multiple precision dairy monitoring technologies in two different studies. For study 1, 56% of predicted gait scores were within 0.25 points of the actual weighted gait score and for study 2, 41% of predicted gait scores were within 0.25 points of the actual weighted gait score. Pearson Correlation for study 1 and 2 was 0.43 and 0.46, respectively. For both studies, the Pearson Correlation yielded results in the low category, when evaluating goodness of fit.

Replacement heifer rearing is critical for the future of the dairy operation, especially to improve genetic merit and maintain herd size. A replacement heifer from the day she is born to the day she calves herself is generally a 2-year investment without potential income. A myriad of options exists on how to manage, fed, and ultimately raise replacement heifers. This study quantifies the costs associated with replacement heifer management decisions from birth to calving related to housing, labor, feed and health. The heifer rearing period can be broken into pre and post weaning sections to allow for more understanding the variation of these different biological time periods. Variation can influence the investment per day and breakdown of resources required from a dairy producer. Total heifer raising cost varied broadly across all management scenarios in our study, with feed and labor consistently representing over 60% of the total cost. After determining the true cost on an individual farm, or providing developed assumed cost for a change in management, producers can better manage current expenses and be more prepared for future investment.

Cattle are essential for the global food industry through the meat and milk production. It is from an economical point of view in our best interest to make cattle as efficient as possible, whether it is milk or beef production, without negatively influencing their health and welfare. That has led to a steady increase in the interest of genetic analysis of cattle. The sequencing and identification of genomic variation has led to the association of genotypes with phenotypes of interest and the discovery of the underlaying genetic risk factors for many diseases and traits. Diseases or monogenetic traits caused by a single nucleotide polymorphism (SNP), small deletions and insertions or other small mutations are often easy to identify if the correct region is found. The diseases caused by structural variants (SVs), variants larger than 50 base pairs (bp) are still challenging. It is more challenging because they are harder to identify, especially using shortread sequencing technologies. It is therefore still a rather unexplored area for cattle and other domestic species.This thesis looks at SVs found in the Swedish Red and Brown (SRB) cattle to discover breed specific SVs. This was done by creating a pipeline with VCF files as input. The identified SVs were filtered and overlapped with externally identified SVs. The pipeline was tested with two SRB datasets. The structural variant caller, DELLY, performed poorly with low read depth data when comparing single replicate data and combined replicates data. Multiple SVs were identified in all individuals and did overlap with both functional and gene annotation. There was also overlap found with datasets in the European variant archive (EVA). This indicates that the identified SVs are shared among multiple breeds of cattle and that DELLY can be used to develop future pipelines to include long read sequencing technologies and/or data with higher read depth.

Enterovirus D68 (EV-D68) is a virus that normally causes disease in children. While this virus typically causes a respiratory infection, in 2014, a large outbreak of the virus was associated with patients that had paralysis of the arms or legs. Even though the virus was discovered in 1962, little was known about the life cycle of the virus or its ability to cause disease. An animal model of disease was needed to understand how the virus causes disease and to develop antiviral compounds to target the virus life cycle. We adapted the virus by serial-passage in lung tissues from mice deficient in interferon receptors. Using the adapted virus, we established a model of respiratory disease where the virus was able to replicate and cause moderate damage to the lung tissue. We created a separate model of disease where the virus caused paralysis and mortality in infected mice, similar to symptoms seen in infected children. Lastly, we evaluated several antiviral compounds to determine if they were able to protect the mice from virus replication and mortality. Guanidine was able to reduce the amount of virus in each tissue as well as protect mice from paralysis and mortality. In addition, human intravenous immunoglobulin (hIVIG), a mixture of pooled antibodies from human donors, did not reduce the amount of virus in the lungs, but did protect mice from paralysis and mortality.

Production of dairy cows is influenced by many factors, among which are: genetics, nutrition, management, disease and age. Most of these factors can be modified to maintain a high level of production. Age, however, is beyond the influence of mankind; therefore, it is important to understand the effect of age on milk and butter-fat production.

One of t he largest problems facing the successful dairyman of today is selection of proper sires to mate to his high producing cows. Many breeders and dairymen have the impression that proven sires will give the same increase in production regardless of the dam's production or the level of environment present. Even though sires come from high producing herds, some as high as 600 pounds of butterfat, the average production of all cows in the state of Utah remains at a much lower figure. The average for all cows in Utah is about 250 pounds of butterfat and the average in 1958 of cows on Dairy Herd Improvement test was 403 pounds. This difference in level of production may be attributed to either genetic or environmental factors and possibly an interaction of the two. Most workers agree that the heritability estimates for milk production and fat yield are from .2 to .3. This means t hat about 25 per cent of the variance in milk yield is due to inheritance, and the other 75 per cent is due to management or environment. Therefore, there is a need to study daughters of the same sire at various levels of production to determine the amount of increase or decrease found at these levels. This thesis presents a study of daughters of Holstein sires used in artificial breeding. Sires in artificial breeding were used because they have a larger number of daughters, and their daughters come from a wide range of production and management levels.

Swiss cheese has been rightly called "king of the cheeses." It has been prized the world over for its stately appearance and sweet "hazelnut" flavor. In grading Swiss cheese, these two things,appearance and flavor, are important considerations in determining the cheese score. Appearance is judges according to the number, type, and size of eyes present in the cheese, with color and body and texture also considered. Flavor is judges according to the degree of sweetness and the amount and kinds of off flavors present. In the past, there has been considerable variation in the quality of the Swiss cheese produces. Causes of this variation were little understood, since wide ranges in grades of cheese were obtained from seemingly similar milk and manufacturing precedures. Technique has been greatly improved by research conducted in both private industry and experiment stations. Much has been done to produce beneficial effects in the cheese, and to reduce detrimental effects. One question, still debated, is the amount of eye forming bacteria necessary to produce the best eye formation. Propionibacterium shermanii, by its production of carbon dioxide, is thought to be the most important bacteria in producing the eyes. Some Swiss cheese makers see no necessity in adding prepared culture of E. shermanii to their milk. They allow the milk to become "seeded" from organisms already present in the vets and on the equipment. Other cheese makers add small amounts of prepared cultures of T. shermanii, whil still others add rather large quantities. Procedure varies from plant to plant. Propionic acid and acetic acid are also produced in the life processes of P. shermanii. These two acids are important factors in the development of flavor in Swiss cheese. Therefore, a change in the amount of P. shermanii in the Swiss cheese, and the subsequent effect on eye formation and flavor. It is the purpose of this experiment to determine the general effects that variations in the size of the inoculation of P. shermanii will produce on eye formation and flavor development. The effects, if any, of the three milk treatments mentioned above will also be noted.

Lactose in milk has relatively low variation regardless of season, breed, or country. The study of lactose concentration and correlation among other milk components is limited. Furthermore, dairy farmers have limited access to the lactose data and are not familiar with it. This study was conducted to: 1) investigate the phenotypic correlation between lactose and other milk components; and 2) determine the importance of lactose for dairy herds. Monthly DHIA records from Utah (DHIA), Dairy Herd Performance Test (DHTP) records from Ibaraki, Japan, and California herd average data (CHAD) covering 27 states were used to analyze the relationships between milk lactose concentrations and parameters related to milk production. Record spans for each data sets for DHIA, DHTP and CHAD were 7 consecutive years ending August 2017, 12 consecutive years ending August 2017, and 9 consecutive years ending August 2017 respectively. Means for the DHIA records were 187.9 days in milk, 34.6 kg/d milk yield, 4.08% lactose, 3.88% fat, 3.15% protein, 8.86% SNF, 14.4 mg/dl MUN, 256,000 SCC, and 2.4 parity. A negative correlation was observed between lactose concentration and parity (r = -0.27). Positive phenotypic correlations between lactose percentage and milk yield (r = 0.28), and negative correlations with fat (r = -0.17), protein (r = -0.21) and SCC (r = -0.30) were observed. No seasonal fluctuations of milk lactose concentrations were observed. Mean for the DHTP records were 4.55% lactose, 3.95% fat, 3.29% protein, 8.74% SNF, 283 mOsm/kg osmotic pressure, 19,600 bacteria count, and 222,000 SCC. A seasonality in the lactose concentrations were observed, with the lowest concentrations of lactose observed in late summer and fall. There were no phenotypic correlations between lactose concentrations and protein, but a negative correlation with fat (r = -0.12) was observed. A significant negative correlation with SCC (r = -0.28) was also observed. Based on the CHAD records, cows with lower lactose concentrations showed a higher culling rate, which indicates that the milk lactose concentration could be a potential indicator of problems in a dairy herd. This study suggest that lactose level could be an indicator for managing dairy farms. Dairy farmers should be able to access lactose data, and these data should be provided by DHIA.

For many years, substitutes for butterfat have been the subject of much controversy. Their acceptance as being nutritionally equal to butterfat has often been question. The importance of this problem lies primarily in its economic and nutritional significance. A recent study of pulic attitudes toward dairy products conducted by Alfred Politz Research, Inc. for the American Dairy Association, shows that 48.4 per cent of the poulation believed that butter is a more nutritions food than oleomargarine. Only 6 per cent thought that oleomargarine is more nutritious while 27.2 per cent believed they are about the same. The remainder, 18.4 per cent, stated that they did not know. Margarine tax laws were in force for some time while vegetable oils were being tested as a human food. In addition to chemical examination, many investigations were conducted with rats, calves, and humans. Although there were still conflicting results, the tax laws were repealed and substitutes wen on the market to compete with butter. Many investigators still question the decision that substitutes are qual to butter, nutritionwise. Many investigations (4, 6, 21, 34) have shown that butter contains one or more growth factors which have not, as yet been identified. Chemical methods have failed to identify any of these factors, and so other methods have been considered. It is a well known fact that interrelationships exist between fat metabolism and the metabolism of other substances. It has been shown (11) that dietary fat affects the metabolism of other nutrients such as calcium and phosphorus. Although not clearly understood, it has been demonstrated (25, 37) that the kidney plays an important role in fat transport and metabolism. The value of urinalysis as a method of indicating the metabolism as a whole is well known, as well as is the high sensitivity of metabolic systems to minute quantities of some substances. The possibility of detecting growth factors or other substances through a study of excreted metabolites seems worthy of consideration in this study. Recent work with paper chromatography at the University of Texas (48) has indicated that each individual has a specific urinary metabolic pattern. Similarities have been found in the patterns of identical twins and schizophrenics. It was also found that the diet changed this pattern to a certain extent, although this was not studied extensively. The problem reported here is a study of urine obtained from highly inbred rats fed animal and vegetable fats analyzed by use of paper chromatography.

Ghrelin is a hormone produced mainly by the cells lining the gastric mucosa. Ghrelin was first extracted from human and rat stomachs, and identified as an endogenous stimulator of growth hormone release. Ghrelin is synthesized and produced in several tissues, but the gastric mucosa remains the major source of circulating ghrelin. Besides growth hormone release, ghrelin stimulates appetite and plays some major roles in different organs. In several studies, ghrelin was described as a hormone with multiple functions and diverse biological actions. Ghrelin exists in two major forms, active ghrelin and inactive ghrelin, and only the active from binds to the receptor. The majority of total circulating ghrelin is inactive ghrelin with no identified function. The aims of the present study were to measure active and total ghrelin in dairy cow’s milk and plasma during early lactation, and to observe changes in the ghrelin concentrations over time. We are interested in this period of time since the milk during early lactation contains a variety of biologically active hormones that are vital for newborn calves. In this study, fifteen Holstein dairy cows were selected randomly from different lactations. Milk and blood samples were taken daily from cows at early lactation for 10 days, and from some cows in mid-lactation. A laboratory test was used to measure active and total ghrelin in milk and plasma samples. Supplementary measurements such as milk fat, lactose, protein, and milk yield were recorded. Active and total milk ghrelin concentrations were found to be significantly higher in the first day of lactation during colostrum production. Interestingly, the percentage of active to total ghrelin in milk and blood was constant in all days tested, suggesting that this constant percentage can be used to estimate active or total ghrelin, if one of them is know, from the same sample. However, no correlation was observed between the percentage of milk ghrelin and plasma ghrelin or with other milk components. In conclusion, the presence of ghrelin in colostrum and milk in measurable amounts of both active and total form suggests that it is a critical compound for the metabolic activity of newborn calves and functions transiently to regulate the activity of some physiological processes until the endocrine system of the new calves starts to function independently.