Supplementing narasin or monensin to control coccidiosis in naturally infected calves.

This experiment compared narasin and monensin as anticoccidials for calves naturally infected with Eimeria spp. Twenty-four weaned, non-castrated male calves (Bos indicus × B. taurus cross) were assigned to this experiment (days -8 to 42). All calves were infected by Eimeria spp. according to oocyst count per gram (OPG) from fecal samples collected on days -8 and -7 (average 1,059 ±â€…101 oocysts/g). Calves were housed in individual pens, received corn silage, mineral mix, and water for ad libitum consumption, in addition to a grain-based supplement at 200 g/head daily. Fecal samples were collected on days -2 and -1 for OPG, and results averaged as initial OPG value. Calves were blocked according to initial OPG into eight blocks of three calves each, ranked within each block according to body weight (BW) recorded on day -1, and assigned to receive narasin (NAR; 0.8 mg/kg of BW), monensin (MON; 1 mg/kg of BW), or no ionophore (CON; negative control). Ionophores were added to the grain-based supplement, and offered from days 0 to 42 of the experiment. Calf BW was recorded on days 7, 14, 21, 28, 35, and 42. Fecal samples were collected on days 6 and 7, 13 and 14, 20 and 21, 26 and 27, 34 and 35, and 41 and 42 for OPG analysis, and results from samples collected on consecutive days were averaged. Aliquoted fecal samples were also pooled across calves from the same treatment and collection days, and used to determine the prevalence of individual species of Eimeria. No treatment effects were detected (P ≥ 0.51) for calf BW or growth rate. A treatment × day interaction was detected (P < 0.01) for OPG, as NAR and MON calves had less (P < 0.01) OPG compared with CON calves beginning on day 7. The OPG was also less (P ≤ 0.03) in MON compared with NAR calves on days 7, 14, and 28, but did not differ (P ≥ 0.48) on days 21, 35, and 42. The anticoccidial efficacy of NAR and MON did not differ (P ≥ 0.16) when calculated across all Eimeria spp., or according to prevalence of E. bovis and E. alabamensins. A treatment × day interaction was detected (P = 0.04) for anticoccidial efficacy to E. alabamensis, which was greater (P < 0.01) in MON calves on days 7 and 14 and did not differ (P ≥ 0.40) afterward. Collectively, both ionophores were similarly effective in controlling coccidiosis upon completion of the 42-d study, although the anticoccidial effects of monensin were noted earlier in the experiment. Nonetheless, these results corroborate narasin as an efficient anticoccidial ionophore for naturally infected calves.

Comparison between the Mission Plus device and gold standard methods for measuring hemoglobin concentrations and packed cell volumes in cattle.

BACKGROUND: A point-of-care device that can provide immediate and reliable hemoglobin (Hb) concentrations and packed cell volumes (PCVs) would be useful in veterinary medicine. OBJECTIVES: We aimed to compare the use of a human device (Mission Plus; MP) with a gold standard (GS) method for measuring Hb concentrations and PCVs in cattle blood. METHODS: Blood samples from clinically healthy cattle (n = 122) were collected with or without an anticoagulant (K2 EDTA). The GS and MP methods were compared with correlation coefficients. Passing-Bablok regression analyses were also performed, and the acceptability judgment was completed using Bland-Altman plots. RESULTS: The CVmax for Hb values obtained using the GS method, the MP device without K2 EDTA, and the MP device with K2 EDTA were approximately 2.70%, 1.70%, and 2.0%, respectively, whereas the CVmax for PCVs was 0.90%, 1.83%, and 2.05%, respectively. A positive correlation (97.5% confidence interval) was observed between the Hb concentrations and PCV values detected using the MP and GS techniques in blood with and without K2 EDTA. Bland-Altman plots showed agreement between the MP and GS methods. For Hb using blood collected with or without the addition of K2 EDTA, the mean differences were -0.87 g/dL (95% CI: 1.35; -3.96) and 0.08 g/dL (95% CI: 2.16, -1.99), respectively. For PCVs using blood collected with or without the addition of K2 EDTA, the mean differences were -3.75% (95% CI: 0.61. -8.12) and -0.88% (95% CI: 2.86, -4.62), respectively. CONCLUSIONS: The MP device can be used to analyze Hb concentrations and PCVs in bovine blood to assist in field diagnoses.