Abstract: To explore the relationship between expression of IGF-Ⅰand development and lactation ability of dairy cow mammary gland, the expression of IGF-Ⅰ in dairy cow mammary tissue was detected using qRT-PCR. The cell culture, qRT-PCR, and MTT assay were also used to test the effects of IGF-Ⅰ on dairy cow mammary epithelial cells. The results showed that expression of IGF-Ⅰ in mammary tissue in puberty cow was the highest. After IGF-Ⅰ addition, IGF-ⅠR expression, proliferation ability of mammary epithelial cells and beta casein expression were raised. The results suggest that IGF-Ⅰ probably promotes IGF-ⅠR expression, further encourages the proliferation of mammary epithelial cells and increases beta casein content.

Key words: dairy cow; IGF-Ⅰ; IGF-ⅠR; expression; lactation