Use of Rate-of-Gain and Dry Lot to Maintain Parasite Anthelmintic Susceptibility in Bluefaced Leicester Maryland Lambs

Project Overview

Project Type: Farmer
Funds awarded in 2018: $13,658.00
Projected End Date: 02/29/2020
Grant Recipient: Vista View Farms
Region: Northeast
State: Maryland
Project Leader:
Andrew Keller
Vista View Farms


  • Animals: sheep
  • Animal Products: fiber, fur, leather, meat


  • Animal Production: animal protection and health, grazing management, parasite control, anthelmintics
  • Education and Training: on-farm/ranch research
  • Production Systems: Dry lot

    Proposal summary:

    In Maryland the barberpole worm, Haemonchus contortus, is the most prominent health concern in young lambs. Lambs are exposed to worms when grazing. Anthelmintics are available; however, worms are becoming resistant. The proportion of animals receiving anthelmintics is the most important factor determining the rate of resistance development. This grant combines the use of rate of gain and a dry lot to reduce treatments. By reducing the number of treatments there is the potential to slow the rate of resistance.

    Approximately 50 lambs will be divided into two groups at weaning. The control group will consist of lambs maintained as one group on pasture. Lambs in the treatment group will be maintained on pasture until a lamb requires treatment at which time it will be moved into a dry lot. We will compare total treatments and rate of gain between the two groups to demonstrate if a dry lot can reduce the number of treatments and increase producer profit. In addition, we will compare the resistance to anthelmintics at the beginning of the study to resistance at the conclusion between both the control and test lambs remaining on pasture.

    We will write an article for the Wild and Wooly newsletter, host a field day, and rely on our technical advisor for additional outreach. Resistance rates should show producers the value of not treating all animals in their flocks. In addition, the concept of a low-cost dry lot design, and value of establishing a dry lot will be demonstrated.

    Project objectives from proposal:

    Our proposed solution is using a rate-of-gain measurements and a dry lot to promote the health of susceptible lambs and reduce the proliferation and spread of anthelmintic resistant parasites.

    There are four objectives.

    1.Compare the number of treatments between co-located pastured lambs (control group), and lambs on pasture with those needing treatment moved into a dry lot (treatment group).

    2.Compare parasites resistance to anthelmintics at weaning to lambs in the control group at market time.

    3.Compare parasite resistance to anthelmintics at weaning to lambs in the treatment group that remained on pasture at market time.

    4.Provide a cost benefit comparison for the purchase of feed versus the added value from reduced lamb loss and/or higher rates of gain in dry lot lambs.

    We anticipate that if lambs needing treatment are immediately placed into a dry lot then the number of treatments required will be lower and parasite resistance will be lower in the treatment group than in the control group or at least remain the same as a resistance rates at weaning. We also anticipate that the increased income from a higher rate of gain and reduced lamb losses will mitigate the cost of purchasing feed while improving animal health.

    Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the view of the U.S. Department of Agriculture or SARE.