Effect of anthelmintics on reproductive performance and first lactation culling rate

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

VETERINARY RECORD

BRITISH VETERINARY ASSOC

Año: 2009 vol. 165 p. 743 - 746

0042-4900

Holstein female calves fed entirely on green pastures were treated with ivermectin from birth to puberty in order to study the effect of parasitic burden of reproductive and productive performance after puberty. Puberty onset, age at first service and age at calving were advanced by 30, 70 and 110 days, respectively (P < 0.05) 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 as well as GH, IGF-1, insulin and prolactin profiles were similar in both groups of cows.  Culling percentage during first lactation was greater in untreated (47%) than in treated (11%) cows (P < 0.05). We conclude that ensuring minimal parasite burden during development in dairy cattle fed in green pastures is beneficial to production, as it advanced the onset of lactation and improved the permanence of the cows in the dairy herd.