Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
ad-mūgĭo, ii, 4, v. n., of oxen, to low or bellow to: admugit femina tauro. Ov. A. A. 1, 279: submissis admugit cornibus Apis, Claud. Cons. Honor. 4, 576; id. Rap. Pr. 3, 443.