Effects of colchicine on milk yield, composition, and cellular differentiation during caprine lactogenesis.

Intramammary colchicine infusion into goats at parturition reduced milk yield by 20% during the 30 day experimental period. During the first week of lactation, milk composition from colchicine-treated udder halves had elevated somatic cell numbers, serum albumin concentration and pH, while citrate concentration was lower in comparison to uninfused glands. Levels of lactose from both infused and uninfused udder halves were normal during the first week of lactation. No differences were observed in degree of alveolar development in tissue samples collected prior to treatment. Light and electron microscopy suggested that colchicine-treated udder halves consisted predominantly of undifferentiated mammary secretory cells, while uninfused udder halves appeared more cytologically differentiated. Results demonstrated that intramammary colchicine infusion at parturition temporarily altered milk composition and inhibited mammary cellular differentiation.