Effect of deworming with ivomec pour-onâ on performance of gra

EFFECT OF DEWORMING WITH IVOMEC POUR-ON
PERFORMANCE OF GRAZING
STOCKER CATTLE
Story in Brief
One hundred twelve healthy stocker steers averaging 533 lb and grazing summer forages were used to evaluate the effect of ivermectin on weight gain.
Treatment groups consisted of one or two treatments with ivermectin and acontrol group receiving none. Cattle receiving treatment with ivermectin hadgreater weight gains over subsequent 28 day grazing periods than cattlereceiving no anthelmintic treatment. Average improvements in 28 day weightgains ranged from 11 to 14 lb/head. Repeated anthelmintic treatments, ifscheduled appropriately, may be beneficial to summmer stocker cattleperformance in eastern Oklahoma.
(Key Words: Stocker Cattle, Deworming, Ivermectin, Anthelmintic.) Introduction
Timely applications of anthelmintics can offer significant economic improvements to cow/calf production in eastern Oklahoma (Smith et al., 1995).
Cattlemen receiving and grazing summer stocker cattle typically deworm atreception of the cattle in the winter or early spring but the scheduling ofsubsequent treatments with an anthelmintic is highly arbitrary. Cattlemen areunsure as to the effect of a singular deworming when cattle are turned to greengrass and the effects of any followup treatments. The objective of this field trialwas to determine the effect of deworming on healthy grazing summer stockercattle.
Materials and Methods
One hundred twelve healthy stocker cattle averaging 533 lb were used to evaluate the effect of ivermectin (Ivomec) on weight gain. Cattle werepreviously received over approximately 30 days in early spring andsubsequently vaccinated for IBR, PI3, blackleg, malignant edema andleptospirosis. Cattle were castrated and dehorned if necessary and dewormedwith ivermectin.
The trial was initiated June 8, 1995. Cattle were randomly allocated to treatment groups, implanted, individually identified with a numbered eartag 1 Area Extension Livestock Specialist 2County Extension Agriculture Agent and weighed. IVOMEC Pour-On (1 ml ivermectin/22 lb body weight) wasapplied to treated cattle. Treatment groups consisted of cattle left untreated toserve as controls (C), cattle dewormed on day 0 only (W1) and cattle dewormedon day 0 and day 28 (W2). Cattle were individually weighed on days 0, 28 andat the termination of the trial on day 56. Treatment groups were comingledand grazed common pastures consisting primarily of bermudagrass. Data wereanalyzed by General Linear Models procedures.
Results and Discussion
Animal performance is shown in Table l. Dewormed cattle gained more weight than control (C) cattle not dewormed at day 0 (14 and 13 lb for W1 andW2 treatment groups, respectively). A followup deworming at day 28 resultedin W2 cattle gaining 11 lb more than W1 cattle and 12 lb more than controlcattle during the same period.
These data demonstrate a benefit to the performance of grazing summer stocker cattle with repeated deworming treatments. Cattle in this trial were notdewormed at the beginning of the grazing season subsequent to deworming attheir reception. Improvement in the total performance of the cattle may havebeen realized had deworming treatments begun earlier. Typical climaticconditions at this time are favorable to the life cycle of beef cattle parasites ineastern Oklahoma. More work is needed to better understand the effect onperformance of repeated deworming treatments to grazing summer stockercattle.
Literature Cited
Smith, S.C. et al. 1995. E-944. Oklahoma State University.
Table 1. Effect of ivermectin on weight gain in grazing stocker steers.
Treatment
a,b Means in the same column with different superscripts differ (P<.05).

Source: http://www.ansi.okstate.edu/research/research-reports-1/1996/1996-2%20Smith%20Research%20Report.pdf