Abstract

An expert system to predict the fertility of beef heifers was developed using the A.I. Toolkit KAPPA-PC 2.3³. The knowledge base was developed from scientific literature and from a beef cattle reproduction expert. The expert system computes an evaluation age, age both at the start and end of the breeding season, and weight per day of age to classify a heifer as having either a ³LOW², ³GOOD², or ³EXCELLENT² likelihood of conception. The expert system summarizes the information that is entered into the computer and creates a text file of the summary. It also gives explanations for every prediction to help identify and alleviate any problem areas that may affect a heifer¹s ability to reproduce. The program requires an IBM compatible computer installed with Windows 3.1³ or greater. From simulated data for purebred or crossbred British cattle, there was 72% prediction agreement between the expert system and the expert. From analysis of historical data of Hereford-Angus crossbred cattle, heifers categorized as ³LOW² and ³GOOD² had significantly higher observed pregnancy rates than expected for each category. There was no significant difference between observed and expected pregnancy rates for heifers in the ³EXCELLENT² category. Pregnancy rates for post-weaning and pre-breeding evaluations for the ³LOW² heifers were found to be lower from the combined ³GOOD² and ³EXCELLENT² heifers at P=.03 and P=.06 respectively. Observed successful calving rates for heifers categorized as ³LOW², ³GOOD², and ³EXCELLENT² did not differ significantly from the expected calving rates for each category.

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