Evaluation of the Impact of Parasite Control With the IVOMEC® SR Bolus Given at Breeding Age on First-Lactation Yield in Holstein Heifers

Authors

  • Luc DesCôteaux Département de sciences cliniques, Faculté de Médecine vétérinaire, Université de Montréal, C.P 5000, Saint-Hyacinthe, Québec, Canada, J2S 7C6
  • Vincent Caldwell Département de sciences cliniques, Faculté de Médecine vétérinaire, Université de Montréal, C.P 5000, Saint-Hyacinthe, Québec, Canada, J2S 7C6
  • Michèle Doucet Département de sciences cliniques, Faculté de Médecine vétérinaire, Université de Montréal, C.P 5000, Saint-Hyacinthe, Québec, Canada, J2S 7C6

DOI:

https://doi.org/10.21423/aabppro19995596

Keywords:

ivermectin bolus, nematode infections, breeding-age heifers

Abstract

A sustained-release ivermectin bolus (IVOMEC® SR bolus) has been proven efficient for the treatment and prevention of nematode infections in growing beef and dairy cattle. However, its effects on growth in breeding-age dairy heifers, as well as on first-lactation yield, have not been demonstrated. This field trial was designed to test the effect of treatment with a sustained-release ivermectin bolus on average daily gain and total weight gain in breeding-age Holstein heifers under commercial pasture conditions in southern Quebec during summer 1995. A follow-up pilot study was undertaken to test the effect of the IVOMEC® SR bolus on first-lactation milk production (projected to 305 days) and milk composition (% fat and protein) in heifers that calved between October 1995 and August 1996.

Cover image of the 33rd Conference Proceedings: Herd of Holstein cattle grazing in a field. Large barn and silos in background. Yellow background.

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Published

1999-09-23

Issue

1999

Section

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