Internal parasites have been reported to flourish in Southern states and cause detrimental economic effects to the beef cattle industry. The objective was to evaluate the effects of anthelmintic therapy administered at recommended dose to spring-calving cows approximately 5 d before the initiation of the calving season. Eighty-two (563 ± 8.1 kg) cows located at the Livestock and Forestry Research Station in Batesville, AR, were stratified by BW, BCS, and fecal egg counts (FEC), then allocated randomly to 1 of 3 treatments representing: Control (CON; no anthelmintic administered; n = 27); Oxfendazole (OXF; n = 27); or Long-acting eprinomectin (LAE; n = 28). Cows were rotationally grazed within individual treatment on 2.4-ha mixed grass pastures. Body weight, BCS, FEC were taken on d 0, 14, 91, 154, and 230 and hair coat scores (HCS) taken on d 0, 91, 154. Beginning May 15, 2015, one bull was placed in each pasture for a 60 d breeding season. Performance data were analyzed using PROC MIXED of SAS, with individual cow being the experimental unit and conception rates were analyzed using Chi-squared. Body weight on any sampling date (d 230 BW 568, 573, 574 kg for CON, LAE, OXF, respectively), BCS on d 0, 14, 154, and 230, and HCS on d 0 and 154 did not differ (P ≥ 0.25) across treatments; however, BCS were greatest (P = 0.03) for OXF (6.0), CON intermediate (5.9), and lowest for LAE (5.8) on d 91, and HCS were greater (P < 0.01) for LAE (3.5) versus OXF (1.7) and CON (2.8) on d 91. Similar (P ≥ 0.16) overall ADG were reported (0.00, 0.08, and 0.05 kg/d for CON, LAE, OXF, respectively). Cow FEC did not differ (P ≥ 0.11) on d 0 or 91; however, were greater for CON on d 14 and 154 versus OXF and LAE; were greater (P = 0.02) for LAE versus CON and OXF on d 230. Conception rates did not differ (P = 0.17) across treatments (78, 61, 81%, for CON, LAE, OXF, respectively). In this study, anthelmintic therapy did not improve BW, BCS, HCS, FEC, or conception rate, in spring-calving cows rotationally grazed over a 230-d grazing period.