An expert system for dairy herd reproductive management for microcomputer was developed using an expert system shell and Turbo Pascal. A dairy extension reproductive specialist provided information for the system and empirical support was provided by research. The expert system initially examines days open, days to first insemination, percent of possible estruses observed, and number of breedings per conception to determine whether a problem exists. Interpretations ranging from “excellent” to “severe” were established for each parameter. “Excellent” and “adequate” interpretations correspond to a 12 to 13 mo calving interval. The system then selects for evaluation one of three areas that influences days open; days to first insemination, efficiency of detection of estrus, or conception percentage. Once an area has been selected for further evaluation, the expert system utilizes information from the user and from DHIA reproductive management reports developed by the Dairy Records Processing Center in Raleigh, NC. The reproductive reports are captured in a computer file and read by the expert system to identify problems of conception categorized by production, parity, service, days in milk, breed, and service sire. In addition, questions are asked by the expert system to isolate problems in data accuracy, semen handling, AI technique, detection of estrus, signs of estrus, and other management areas. Recommendations and suggestions are given. The expert system was designed to be used by extension personnel who may not have extensive knowledge of computers or reproductive management. The compiled program runs on an IBM compatible personal computer with 640K memory. Ten Virginia DHIA herds with conception problems were evaluated by the expert system and the extension specialist. Of 100 potential problem areas, the expert system and extension specialist identified 47, agreeing on 85% of them. Most discrepancies resulted from the expert applying a more restrictive standard when values were close to a preselected threshold. / Master of Science

Dairy farmers in Virginia are confronted with the problem of continually re-organizing and adjusting their farming operations in an effort to maintain or improve their competitive position. Increasing competition in dairying within the state, as well as potential competition developing in areas outside of the state, makes it essential that dairymen operate efficiently. In particular, they must give careful consideration to various ways of reducing their production costs. Feed costs make up 50 to 60 percent of the total cost of producing milk. Consequently, the feeding program on any dairy farm greatly affects the cost of producing milk and, ultimately, the net return to the farmer. This study had four objectives: (1) to determine the available resources and their restrictions on the farms included in this study; (2) to determine an optimum forage and grain production system and forage to grain feeding ratio for three levels of milk production per cow with milk sales at the blend price not to exceed the present total base sales; (3) to determine which of the three levels of milk production is the most profitable at the present blend price of $5.73 per 100 pounds; (4) to study the effect of changes in the price of milk on the relative profitability of the three levels of production per cow and the forage-to-grain feeding ratios when the amount of profitable milk production is less than the present base. / Master of Science