Abstract

This study analyzes different factors that affect the success of artificial insemination of cows by small farmers involved in a productive and genetic improvement program in the O´Higgins region of central Chile. The success of artificial insemination was modeled as a function of different biological, environmental, and social factors recorded by the program using logistic regression. The model output was the gestational status of the inseminated cows as diagnosed by ultrasound. All predictors were evaluated for unconditional associa-tions with the outcome. The results showed that the pregnancy probabilities in cows from Cardenal Caro Province were higher than those from Cachapoal Province; inseminators with 10 or more years of experience had greater pregnancy success than those with 1-4 years of experience; the pregnancy odds decreased on farms with 30 or more cows compared with farms with 1 to 5 cows; and the pregnancy odds also decreased when AI was performed at a fixed time compared with heat detection. Thus, the province, the number of cows in the herd, the experience of the inseminators, and the type of insemination were associated with the success of the pregnancy.