Estimation of Feed Intake and Digestibility in Grazing Cattle Using Alkane Indicator Technique

Abstract

This study examined the estimation of the Dry-Matter Intake (DMIe) and Digestibility (DMDe) and the utilization of the pasture by grazing cattle in different seasons of the Kars region by using alkane indicator technique. Two experiments were carried out, and in the first experiment, 5 male cattle (mean LW. 244.5 +/- 2.3 kg) were used for 20 days. In first experiment, the precision and reliability of alkane indicator technique were determined by comparing the real Dry Matter Intake (DMI) and Dry Matter Digestibility (DMD) which was obtained by the controlled indoor study with DMIe and DMDe estimated by using alkane indicators. The second experiment was conducted with the pasturing cattle in meadow in 5 terms each lasted 20 days. Ten male cattle (mean LW. 164.9 +/- 1.5 kg) were divided in two groups, and different animals were used in each term. The best result for DMIe was obtained by using the alkanes C-33:C-32 couples in mixed (collected in 24 h) samples in indoor study (R-2:0.86). DMDe's calculated by using alkanes C-32 and C-33 were similar to the real DMD, whereas the DMDe's with alkane C-36 were underestimated (P<0.05). The results obtained with indoor study showed that alkane indicator capsules could be used successfully as a dosing method in alkane indicator method. According to the second experiment results, it was determined that the animals, grazing in the pasture in Kars conditions, were not able to get required nutrient from the pasture towards the end of August.