Diagnosis of Early Pregnancy in Cattle by Ovarian Analysis

Abstract

For a group of cows which did not return in estrus by approximately 25 days following service, sizes of ovaries, corpora lutea, and follicles were evaluated, on a scale of 1-5, by rectal palpation at 8-18 and again at 23-30 days post-service. Changes in size of ovaries and their structures were evaluated as an algebraic difference between the values for the first and second palpations. Three criteria, based on degree of change in size of ovaries and ovarian structure, were employed for pregnancy detection. When all cows were considered, the criteria varied in accuracy from 76-85%. When the calving and non- calving groups were considered separately, however, the accuracies of prediction were quite different. For the 218 cows which calved, the accuracies of the three criteria were 100, 99, and 92%; for the 90 return cows the values were 17, 34, and 67%. The fact that every cow which had a decrease in size of ovary of as much as two units (from the first to the second palpation) was open, suggests an application of the information for the detection of early pregnancy in cattle. © 1968, American Dairy Science Association. All rights reserved.