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Biomedical subjects

G W Hill

Publications and source records attributed to G W Hill.

18 recordsLinked to original sources
PubMed1998

Design and implementation of the United States National Animal Health Monitoring System 1995 National Swine Study.

The United States Department of Agriculture's National Animal Health Monitoring System 1995 National Swine Study was designed to estimate management, health and productivity parameters on pig operations in the United States. Sixteen major swine-producing states that accounted for nearly 91% of June 1, 1995 swine inventory and nearly three-fourths of United States swine producers were included in the study. In the initial phase of the study, National Agricultural Statistics Service enumerators collected information from 1477 producers involved in all phases of swine production (farrowing, nursery, and grower/finisher). Of these, 405 operations with > or = 300 finisher pigs (with at least one finisher pig > or = 54 kg) participated in the subsequent component of the study, which involved on-farm visits by state and federal veterinary medical officers and animal health technicians, and which concentrated on the grower/finisher phase of production. Of those eligible to take part in the second phase of the study, participation was higher among independent producers (48.3%) than among contract producers (15.3%). Participation was also higher among operations that used advanced record-keeping systems (such as record cards for individual breeding hogs or a computer-based record-keeping system). Thus, study results could have been influenced by response biases. As a biosecurity measure, 40.5 +/- 2.1% of operations restricted entry to employees only. For operations that permitted non-employees to enter the premises, relatively few enforced other biosecurity measures on visitors (0.4 +/- 0.1% required feed-delivery personnel and livestock handlers to shower before entering the premises; 3.3+/- 0.9% required a footbath; and 7.0 +/- 1.5% required feed-delivery personnel and livestock handlers not to have visited another operation with pigs on that day). The most common method of waste storage (used by 49.9 +/- 3.8% of operations with > or = 300 finisher pigs) was below-floor slurry or deep pit.

Animal Husbandry↗
PubMed1997

Health status of preweaned dairy heifers in the United States.

The first national estimates of mortality and morbidity for preweaned dairy heifers in the US were generated from monitoring heifers from 906 operations in 28 states prospectively using a daily diary card system. Results indicated that the cumulative mortality incidence risk from birth to 8 weeks of life was 6.3% with a peak of 1.9% during the first week of life. Season of birth was significantly associated with cumulative mortality incidence risk, and mortality risk was highest in the periods January to March and October to December. Cumulative incidence risk of diarrhea to 8 weeks of age was 24.6% with a peak of 15.4% during the second week of life. Diarrhea incidence risk varied by region, with the West having the highest incidence risk (30.5%) and the Northeast the lowest (19.2%), as well as by herd size, with the smallest herd size having the lowest reported incidence risk of diarrhea to 8 weeks of age (18.8%). Other reported 8 week cumulative disease incidence risks included listlessness, 10.0%; respiratory disease, 8.4%; dehydration, 4.1%; lameness or joint problems, 1.1%.

Aging↗
PubMed1997

Design and implementation of the United States National Animal Health Monitoring System 1994-95 Cattle on Feed Evaluation, and an evaluation of the impact of response biases.

The 1994-95 Cattle on Feed Evaluation was a cooperative project (sponsored by the United States Department of Agriculture) involving Washington State University, state agricultural departments, and several agencies of the United States Department of Agriculture). The project focused on cattle-on-feed operations in 13 states that accounted for over 85% of the United States cattle on feed inventory. Participants were selected from National Agricultural Statistics Service list frames. Questionnaires were administered by telephone to operations with a one-time capacity of fewer than 1000 cattle; larger operations were visited twice to administer questionnaires. The participation rate for the first phase of the study was 56.7%. Ninety-one percent of eligible operations completed the second phase of the study. Data summarized from this national study can be used to profile management practices on cattle-feeding operations in the United States. Differences between participants and non-participants did not appear to be great. However, one does need to be mindful of the fact that a small percentage of the producers accounted for the vast majority of feedlot cattle marketed when interpreting the results.

Animal Feed↗
PubMed1994

The National Dairy Heifer Evaluation Project: a profile of heifer management practices in the United States.

The National Dairy Heifer Evaluation Project was a cooperative, USDA-sponsored project involving state agricultural departments, the Cooperative Extension Service, the National Agricultural Statistics Service, and the Animal and Plant Health Inspection Service. A series of retrospective and prospective descriptive surveys using a multiple list and area frame sampling technique were conducted. Information collected pertained primarily to dairy neonates and replacement heifers. Much of the study was related to observational information on health and management characteristics that can be related to the animals' long-term physical and economic performance. The data reflect herds representing 78% of the national dairy cow population. Average herd size was 86 milking and dry cows and 66 heifers. Many characteristics of these herds reflect accepted and recommended practices in the area of dairy replacement management and nutrition. Data summarized in this national study can be utilized to evaluate the impact of management practices on dairy operations.

Animal Nutritional Physiological Phenomena↗
PubMed1985

Memory for two types of spatial location: effects of instructions, age, and format.

Three experiments, with old persons (59-80 years) and college students (17-30 years) in Experiments 1 and 2 and with college students (17-24 years) in Experiment 3, investigated the differences between two types of spatial location memory: memory for the location of individual items in an array and memory for occupied, as opposed to unoccupied, locations in an array. Young persons performed better than old persons on both measures of location memory. However, an effect of instructions (intentional vs. incidental for spatial location) was consistently obtained for memory for occupied, as opposed to unoccupied, locations, whereas no effect of instructions was obtained for memory for individual item locations. In addition, item location memory was superior for objects as opposed to matched words (Experiment 2), whereas occupied location memory was not affected by presentation format (Experiments 2 and 3). These differences indicate that spatial memory is a complex process whose properties are affected by variations in stimulus characteristics and task demands. It was concluded that the distinction of Hasher and Zacks (1979) between automatic and effortful processes is not adequate for understanding spatial memory. A recognition of the complex nature of spatial processing suggests a resolution of discrepancies in the literature based upon differences in stimulus characteristics, task demands, and the effectiveness of task-appropriate mnemonic strategies.

Adolescent↗
PubMed1979

Comparison of the tuberculin Tine Test+ and the Mantoux.

Re-evaluation of recently published figures comparing the tuberculin Tine Test+ and the Mantoux showed that, contrary to original opinion, the Tine Test+ did perform satisfactorily, the reason for the apparent ineffectiveness lying in the original interpretation of the results.

Diagnosis, Differential↗