Prediction of Fertility of Virginia Beef Heifers Using Expert Systems Technology
Wilson II, Lawriston A
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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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