Evaluación de suplementos alimenticios conteniendo torta de higuerilla sobre la degradación in situ de dietas con pasto kikuyo y la producción lechera en vacas Holstein

Colorimetric method as alternative to chromium (III) quantification in cattle feces

“…Likewise, there is no significant difference between the stool production calculated with the paired data obtained through the two methods (p > 0.05). For all cases, the average fecal output values estimated within digestibility trials with this marker are close to the reference values reported by different researchers for the forage evaluated under similar grazing conditions, which range between 3.30 and 4.70 kg DM day -1 (Ramírez & Giraldo, 2017), indicating that the implementation of the colorimetric method for the estimation of FO under grazing in supplemented animals turns out to be satisfactory. Although it has been found in studies of comparative evaluation of markers that with Cr2O3 intake overestimation occurs, this problem is often attributed to the traditional analytical technique (Canesin, Fiorentini, & Berchielli, 2012) or other factors related with the internal markers (Guzman et al, 2017), so optimization of this method constitutes an important advantage for the use of the technique in digestibility tests.…”

“…For fecal output estimation, stool samples were collected from eight multiparous Holstein cows with variable lactation periods, and average live weight of 653 ± 71.2 kg LW; these were maintained under grazing conditions with ad libitum consumption of water, mineralized salt and Kikuyu grass (Pennisetum clandestinum) with regrowth days between 32 and 40 days and offering between 2.6 and 4 kg of DM 100 kg -1 LW. The external marker was supplied during the milking periods in two daily doses of 10 g of Cr2O3, offered during the supplementation with commercial concentrates (Ramírez & Giraldo, 2017). For each animal, control stool samples (H0) were taken prior to the delivery of the marker.…”