Growth of suckling beef calves in response to parenteral administration of selenium and the effect of dietary protein provided to their dams.

OBJECTIVE: To determine whether parenteral administration of selenium (Se) to calves and the amount of forage and protein provided to their dams affects unadjusted body weight, adjusted 205-day body weight, and average daily gain (ADG) of suckling beef calves. DESIGN: Randomized controlled field trial. ANIMALS: 151 Hereford-Angus crossbred beef calves. PROCEDURE: Newborn calves, randomly assigned to 1 of 3 groups, served as untreated controls (n = 49) or were given Se (0.05 mg/kg [0.023 mg/lb] of body weight, SC) once within 2 days of birth (55) or within 2 days of birth and on days 70, 114, and 149 (47). Until day 149, cow-calf pairs were pastured in fields in which the amount of available forage was high or low and supplemental protein was or was not provided. Calves were weighed on days 1, 70, 149, and 209. On days 160 and 209, blood was obtained from 33 calves for measurements of Se concentration. RESULTS: Mean consumption of supplemental protein was 0.65 kg/dam/d. Between days 1 and 70, calves that received the first of 4 multiple injections of Se had significantly greater ADG than control calves. Average daily gain for calves given only 1 injection was not significantly different from controls. Between days 70 and 149, ADG of calves increased with dietary supplementation of protein to their dams. CLINICAL IMPLICATIONS: Strategic administration of Se to calves and dietary supplementation of protein to their dams may result in greater ADG in suckling beef calves during specific time intervals.

Efficacy of ethylenediamine dihydriodide as an agent to prevent experimentally induced bovine foot rot.

Ethylenediamine dihydriodide (EDDI) was administered by capsule and as a feed premix to cattle in 2 studies. In study I (32 steers), EDDI was given at 0, 12.5, 50, and 200 mg/animal each day and in study II (36 steers) at 0, 30, and 200 mg/animal each day. Serum iodine levels were monitored during the studies. The cattle were inoculated intradermally in the interdigital space with a mixture of Fusobacterium necrophorum and Bacteroides melaninogenicus to induce acute foot rot at day 15 (study I) or day 28 (study II) after EDDI administration was started. Lesions and lameness were evaluated 5 days after challenge exposure, using a subjective scoring system. The cattle receiving EDDI had significantly less severe lesions and lameness than control cattle in both studies (study I, P less than 0.003; study II, P less than 0.001). The results indicated that EDDI was efficacious in prevention of foot rot. The studies demonstrated a direct relationship between dosage levels of EDDI and serum iodine levels. However, at the large dosage level (200 mg) there were some individuals that showed an inability to metabolize and excrete the iodine as demonstrated by high serum iodine levels (600 to 700 micrograms of iodine/dl of serum).