| dc.description.abstract | Two experiments were conducted to compare various ectoparasite control strategies and viral vaccine regimens in feedlot cattle to determine the impacts on performance, health, parasite burden, acute phase proteins, and antibody titers. In experiment 1, angus bulls and steers (n = 100; bulls = 64, steers =36) were blocked by sex and body weight (BW) and assigned to 1 of 4 experimental treatments: a control (CON; no fly control), abamectin and piperonyl butoxide insecticide tags (FT), permethrin and piperonyl butoxide pour on (PO), or a garlic-powder top dress (GR) administered at 0.28 g dot-1 animal dot-1 d. No differences were observed in final BW, average daily gain (ADG), dry matter intake (DMI), or gain to feed (G:F) overall (P >/= 0.30). There was a tendency (P </= 0.10) for GR to have decreased BW on d 28 and decreased ADG from d 0 to 28. Fly abundance tended to differ on wk 1 and wk 6 (P </= 0.10). In experiment 2, angus or crossbred calves (n = 406) were assigned to 1 of 2 experimental treatments: a modified-live virus (MLV) vaccine (Titanium 5, Elanco Animal Health) or an inactivated (INA) vaccine (ViraShield 6; Elanco Animal Health, Greeneville, IN). No main effect of treatment (P >/= 0.21) was observed for BW from d 0 to 56. A main effect of treatment (P < 0.01) was observed from d 0 to 56 for ADG with MLV being greater than INA. Dry matter intake was greater for MLV than INA from d 28 to 41 and overall (d 0 to 56; P </= 0.01). Gain:feed did not differ between treatments (P >/= 0.22). However, a main effect of treatment (P < 0.001) was observed for BVDV 1a titers, where INA was greater than MLV. A day x treatment interaction (P = 0.03) was observed for BVDV 1b, both treatment titers increased from d 0 to 14, while INA increased more rapidly. From d 15 to 56 INA BVDV 1b titers remained fairly constant while MLV decreased from d 15 to 28, increased rapidly from d 29 to 42, then decreased through d 56. No treatment x day interaction was observed (P > 0.73) for serum amyloid A (SAA). However, a main effect of day (P = 0.01) and a tendency for main effect of treatment (P = 0.07) was observed. No treatment x day interaction and no main effect of treatment (P >/= 0.72) was observed for haptoglobin. However, a main effect of day (P = 0.002) was observed, Hp concentrations increased from d 0 to 14, then decreased from d 14 to 56. Morbidity, clinical severity score, and rectal temperatures did not differ between treatments (P >/= 0.22). | |
