Clauson (1972)
An etimological dictionary of pre-thirteenth-century Turkish
p. 391
D buza:ğu:la:-
Den. V. fr. buza:ğu:; (of a cow etc.) ‘to calve’. S.i.s.m.l. w. phonetic changes. Türkü viii ff. ürü:p esri: ingek buza:ğu:laçı: bolmuş ‘a white dappled cow was on the point of calving’ IrkB 41 (the form is grammatically impossible, ? error for buza:ğu:la:daçı:): Xak. xi Kaş. III 91 (yeni:-).