Mammary gland development is affected by anthelmyntic treatment in dairy heifer calves. (Hormonal control of milk production in bovines. Effect of verminous nematodiasis during the cow¹s development and reproductive stages. Part 2: Effect of parasitis

MEJIA, ME; PERRI, AF; LICOFF, N; LAZARO, L; MIGLIERINA, M; FERNÁNDEZ-IGARTÚA, MB; BECU-VILLALOBOS, D; LACAU-MENGIDO, I

Calgary, Canada

Congreso; 22nd WAAVP conference; 2009

World Association for the Advancement of Veterinary Parasitology

Nematode gastroenteritis is a severe impairment for beef and dairy calves’ growth in grazing systems. As we previously demonstrated that IGF-1 is diminished in parasitized dairy heifers, and this hormone has been involved in prepubertal mammary growth, we wished to determine if parasite infection could also affect mammary gland development. Forty new born female Holstein calves were randomly assigned to treated (systematic treatments with ivermectin, fenbendazole or levamisole to minimize parasite burden) or untreated group. At 22, 32, 42 and 70 weeks of age, blood samples were taken from all animals for IGF-1 determination by RIA, and six heifers per group were randomly assigned to mammary biopsying. Biopsy samples were taken using a Tru-Core® Biopsy Needle, Medical Device Technologies, Inc.. Histological development of the mammary parenchyma was evaluated and compared between groups. Mammary parenchyma was embedded in fat pad, conforming ductal developing structures of epithelial cells. As the animal grew up more organized ductal structures were observed. Heifers in the treated group had higher ratio of epithelial cells/total area at 22 weeks of age. IGF-1 increased with age and was augmented in the treated group, as expected. We conclude that  effective nematode control, to minimize parasite burden, during development could increase early ductal mammogenesis in association with increased IGF-1 levels. Molecular studies will be performed in further studies.