Thesis (Ph. D.)--University of Missouri-Columbia, 2002. / Typescript. Vita. Includes bibliographical references (leaves 103-104). Also available on the Internet.

ABSTRACT Heartwater, a tick-borne disease caused by Ehrlichia ruminantium, is considered to be a significant cause of mortality amongst domestic and wild ruminants in South Africa. The main vector is Amblyomma hebraeum and although previous epidemiological studies have outlined endemic areas based on mortalities, these have been limited by diagnostic methods which relied mainly on positive brain smears. The indirect fluorescent antibody test (IFA) has a low specificity for heartwater organisms as it cross-reacts with some other species. Since the advent of biotechnology and genomics, molecular epidemiology has evolved using the methodology of traditional epidemiology coupled with the new molecular techniques. A new quantitative real-time polymerase chain reaction (qPCR) test has been developed for rapid and accurate diagnosis of heartwater in the live animal. This method can also be used to survey populations of A. hebraeum ticks for heartwater. Sampling whole blood and ticks for this qPCR differs from routine serumsampling, which is used for many serological tests. Veterinary field staff, particularly animal health technicians, are involved in surveillance and monitoring of controlled and other diseases of animals in South Africa. However, it was found that the sampling of whole blood was not done correctly, probably because it is a new sampling technique specific for new technology, where the heartwater organism is much more labile than the serumantibodies required for other tests. This qPCR technique is highly sensitive and can diagnose heartwater in the living animal within 2 hours, in time to treat it. Poor sampling techniques that decrease the sensitivity of the test will, however, result in a false negative diagnosis. This paper describes the development of a skills training programme for para-veterinary field staff, to facilitate research into the molecular epidemiology of heartwater in ruminants and eliminate any sampling bias due to collection errors. Humane handling techniques were also included in the training, in line with the current focus on improved livestock welfare.

This item was digitized as part of the Million Books Project led by Carnegie Mellon University and supported by grants from the National Science Foundation (NSF). Cornell University coordinated the participation of land-grant and agricultural libraries in providing historical agricultural information for the digitization project; the University of Arizona Libraries, the College of Agriculture and Life Sciences, and the Office of Arid Lands Studies collaborated in the selection and provision of material for the digitization project.

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32 pp. / Originally developed in Iowa and adapted for Arizona. Arizona Youth Livestock Quality Assurance Trainer's Reference; Arizona Youth Livestock Quality Assurance Activity Guide. / The youth manual is a reference manual for the youth livestock quality assurance program. The curriculum is designed to provide youth and adults with a better understanding of the risks involved in the food production industry, better understand the good Production Practices (GPP's) that can help them produce a safer product and therefore, implement these GPP's in their own livestock production system.

32 pp. / Originally developed in Iowa and adapted for Arizona. Arizona Youth Livestock Quality Assurance Trainer's Reference; Arizona Youth Livestock Quality Assurance Activity Guide. / The youth manual is a reference manual for the youth livestock quality assurance program. The curriculum is designed to provide youth and adults with a better understanding of the risks involved in the food production industry, better understand the good Production Practices (GPP's) that can help them produce a safer product and therefore, implement these GPP's in their own livestock production system.

A brief outline introduces the problem of accidental injury, leading to an extensive literature review. Major weaknesses are established in current preventative measures and in accident data on which statistical analysis is based. The importance of design in reducing accidents in livestock buildings is stressed. Hypotheses are formulated and a systems approach adopted to structure analysis of human injury in livestock buildings. Data on agricultural accidents are statistically analysed producing histograms and measures of association between variables. Drawbacks of existing data and coding procedures are identified. A detailed coding frame is assembled and designed to retain relevant aspects of events and circumstances in accident causation. Enumeration of data enables univariate data description, and leads to investigation of variables by two- and three-way tables. Results and drawbacks of this analysis are discussed, and work is directed towards developing methods for data collection. This is based on fifty farms in Grampian region, and results in the design of an investigatory procedure for accidents at all levels of injury severity, using techniques such as interviews, questionnaires, observations, measurements and simulations. Cattle handling procedures are identified as an area of critical concern, and lead to a study of routine cattle handling by the application of observational methods. Analysis of data demonstrates methodological problems. Hypotheses are formed de novo and tested. Results are discussed and means of assessing stockmen's efficiency suggested. Research is integrated by considering the role of the designer in postulating preventative measures in cattle buildings, through an examination of five building types. Discussions with farmers, designers and HSE inspectors, results in a critical evaluation of problem areas. A conceptual framework and a broad sequence of decision making are presented to aid designers to establish preventative measures. Finally, hypotheses formulated previously are discussed in conclusion.

The effects on production of milking grazed crossbred cattle (32, 53 and 74 cow and heifer dams in experiments 1, 2 and 3 in 1986, 1987 and 1988 respectively) with or without a dietary supplement (2kg dairy meal daily for 3 to 4 months post-partum) were studied in a semi-arid area of Kenya. During the second and third trials, half the calves from the milked and also the unmilked groups were creep fed for 4 months commencing approximately 1 month from birth. Herbage dry matter intake was determined four times during the wet and dry seasons between November 1988 and May 1989, and the deterministic model and computer program of the bioenergetic system of lactating and pregnant cattle of Bruce <i>et al</i> (1984) used to examine the performance of the crossbred cows, and to evaluate its potential applicability. The respective mean extracted milk yields over a six month lactation were 670.6, 414.4 and 371.2 kg for the milked and supplemented (MS) groups, and 563.4, 398.4 and 331.1 kg for the unsupplemented (MNS) groups during experiments 1, 2 and 3 (P> 0.05). Mean daily calf growth rates were affected by milk offtake (P< 0.05). They were respectively, 0.52, 0.48, 0.79 and 0.71 kg during experiment 1; 0.64, 0.61, 0.72 and 0.72 kg during experiment 2; and 0.59, 0.57, 0.66 and 0.66 kg during experiment 3 for the milked (MS and MNS) and the control groups (not milked and supplemented, NMS and the not milked and not supplemented, NMNS). Overall, post-partum supplementation improved dam liveweight gain (P< 0.05) but milk extraction tended to reduce it (P> 0.05). Similarly, calving indices were improved by supplementation while the effect of milking was inconsistent. Both creep feeding of the calves and beef genotypes of the dams were not significant (P> 0.05) factors affecting performance. Similarly, body condition scores (1 to 9 score scale) ranged between condition score 4 and 5 for all treatments. The respective mean daily dry matter intakes were 8.5 and 8.2 during the wet, and 8.6 and 8.2 kg during the dry periods; and the corresponding dry matter digestibilities were 0.72 and 0.74 in the wet, and 0.67 and 0.62 during the dry periods. The discrepancies between observed and predicted values of milk (energy), though not for liveweight, were small, consequently, with a few refinements the bioenergetic model may find a useful role in cattle production systems in the semi-arid tropics. It was concluded that the offtake of milk from suitable crossbred cattle in the semi-arid areas may be increased without significantly reducing offtake of slaughter animals.

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The nucleic acids digested by ruminants are essentially of microbial origin. Absorbed purines are extensively degraded and excreted in urine as allantoin, uric acid, xanthine and hypoxanthine. The measurement of the urinary purine derivatives could be used to estimate the uptake of purines and hence that of microbial protein. 1) Automated methods for measurements of purine derivatives were improved. A HPLC method for determining total adenine and guanine was used to measure the purine contents of mixed rumen bacteria and the digestibility of microbial purines in sheep. 2) Endogenous excretions of purine derivatives by sheep and cattle of different physiological states were measured using animals nourished by intragastric infusions of VFA and casein. The species difference in and the effects of changes in protein supply on the endogenous excretion were studied. 3) A microbial nucleic acid extract was infused into the abomasum of lambs at 6 levels. The subsequent urinary excretion of purine derivatives was examined. The results suggested that exogenous purines were utilised by the sheep. A model is proposed to describe the relationship between purine derivative excretion and purine uptake. 4) Allantoin was infused intravenously to sheep and the changes in plasma concentration, nephric tubular re-absorption and urinary excretion of allantoin were studied. Results showed that plasma allantoin was rapidly removed and a constant proportion of the allantoin entering the blood was excreted in urine of sheep. 5) Secretion of allantoin and uric acid into the gut via saliva was quantified in sheep. The possible decomposition of the allantoin in the rumen by microbes in the rumen fluid and in the rumen wall of sheep was examined <i>in vitro</i> and <i>in vivo</i>. Allantoin infused into the rumen or abomasum of sheep and cattle was not recovered in urine. 6) A model for calculation of microbial protein available to sheep is proposed. It is suggested that a different model should be used for cattle. These models were applied in two feeding experiments with sheep and steers.