Journal of Animal and Veterinary Advances

Year: 2006
Volume: 5
Issue: 6
Page No. 522 - 527

Predicting the Probability of Conception in Artificially Inseminated Bovines-A Logistic Regression Analysis

Authors : M. Thirunavukkarasu and G. Kathiravan

Abstract: A study was undertaken to estimate the probability of conception in artificially bred bovines, based on various animal and environmental factors, based on the data collected from 2,283 bovines (1,942 cattle and 241 buffaloes) inseminated at 30 artificial insemination centres in six districts of North-eastern agroclimatic zone of Tamil Nadu State (India). Logistic regression technique was employed to estimate the probability of a particular breedable bovine female not being able to conceive of an artificial insemination. Wald statistic obtained for the independent variables indicated that the coefficients for the variables-species, lactation order, stage of lactation, milk yield, reproductive disorders, distance to artificial insemination centre and month of insemination were all significantly different from �0� at 1 degree of freedom. Positive values of �R� statistic obtained for species, stage of lactation, reproductive disorder, distance to artificial insemination centre and month of insemination indicated that as these variables increase in value, the likelihood of conception increased by 7.2795, 2.7478, 2.5638, 2.7453 and 1.9778, respectively. The negative �R� in the case of average milk yield indicated that the likelihood of conception decreased by 0.1973. Small values of �R� for the statistically insignificant variables such as breed, farm size, land holding and lactation order indicated that these variables had got only smaller partial contributions to the model. Again, 1510 animals not conceived of AI were correctly predicted by the model not to have conceived. Similarly, 745 animals conceived were correctly predicted to have conceived. Of the animals not conceived, 98.82% were correctly classified, while of the animals conceived, 98.68% were correctly classified. Overall, 98.77% of the 2283 bovines were correctly classified to have conceived/not conceived.

How to cite this article:

M. Thirunavukkarasu and G. Kathiravan , 2006. Predicting the Probability of Conception in Artificially Inseminated Bovines-A Logistic Regression Analysis. Journal of Animal and Veterinary Advances, 5: 522-527.

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