Effect of ivermectin treatment during growth on productive and reproductive performance of grazing dairy cows

MEJIA, ME; MIGLIERINA, M; PERRI, AF; FORMÍA, N.; BECU-VILLALOBOS, D; LACAU-MENGIDO, I.M.

JOURNAL OF ANIMAL SCIENCE

Año: 2007

0021-8812

Holstein female calves were treated with ivermectin from birth to puberty in order to study its postpubertal effects. Growth and reproductive parameters in heifers, and production and reproduction in cows during first lactation were registered, and endocrine variables were measured.  Puberty onset, age at first service and age at calving were advanced in ivermectin treated animals compared with untreated ones. No significant differences were observed in conception rate, number of services and calving features between both treated and untreated groups. Daily milk yield and fat content in milk during first lactation were similar in both groups of cows as well as GH, IGF-1, insulin and prolactin profiles. Culling rate was greater in untreated than in treated cows. We conclude that continuous ivermectin treatment during development in dairy cattle is beneficial to production as it advances the onset of lactation and improves the permanence of the cows in the dairy herd.