CHEMICAL AND NUTRITIONAL PARAMETERS OF THE KUDZU (Pueraria phaseoloides) HARVESTED IN THE WINTER AND SUMMER SEASONS.

Abstract

Two experiments were donde using a simple reversion design in which were studied two harvesting ages of Kudzu, during the winter and the summer seasons: 3.5 and 5.5 months, respectively. In both studies were used young bulls of aproximately 300 kg of alive weight, which were controlled and fed under confinement. With the material of winter, which was supplied fresh to the animals, the relationship leaf-stem decreased with the harvesting age (1.162 and 0.930), as the content of brute protein (17.50 and 15.60%) and tannins (2.61 and 2.23%); on the other hand, the FDN content increased with the harvesting age (70.05 and 73.85%). The content of digestible energy (2.63 and 2.31 Mcal/kg M.S., P≤0.05) and metabolizable energy (2.30 and 1.98 Mcal/kg M.S., P≤0.05), decreased with the harvesting age. The consumption of dry matter (38.1 and 42.3 g/kg of PV^(0.75)/day, P≤0.15), edigestible protein (5.36 and 4.52 g/kg of PV^(0.75)/day, P≤0.01) and digestible energy (102 and 98 Kcal/kg of PV^(0.75)/day, P≤0.15) decreased with the harvesting age, no thus the consumption of digestible dry matter (P≥0.15), brute protein (P≥0.15) and metabolizable energy (P≥0.15), and averages of 18.5 g, 7.0 g, and 83.0 Kcal/kg of PV^(0.75)/day, respectively. The apparent digestibility in vivo of dry matter (49.2 and 43.2%, P≤0.10), protein (74.1 and 66.5%, P≤0.01) and energy (53.1 and 45.5%, P≤0.05) decreased with the harvesting age. The summer material was used in hay form. The results suggest a decreasing in the relationship leaf/stem (0.510 and 0.452), brute protein (14.25 and 13.08%), tannins (1.23 and 0.75%) and FDN (83.97 and 80.39%) to increase the harvesting age. There was not difference among the treatments in the content of brute energy (4.56 and 4.63 Mcal/kg MS), but it was observed a decreasing in the digestible energy (1.62 and 1.34 Mcal/kg MS) and metabolizable energy (1.37 and 1.19 Mcal/kg MS) when increase the harvesting age. There was not significant difference (P≥0.15) in the consumption of dry matter, digestible dry matter, brute energy and digestible energy among treatments, with average values of 67.0 g, 23.4 g, 307 Kcal and 87 Kcal/kg of PV^(0.75)/day. The consumption of brute protein (10.3 and 8.7 g) and digestible protein (5.7 and 4.5 g/kg of PV^(0.75)/day) was high during the first 3.5 months of age (P≤0.15). There was not difference in the digestibility of the MS (dry matter) (P≥0.15) (x=35.0%), but the digestibility of the PC (Brute Protein) (56.9 and 51.5%, P≤0.10) and energy (36.1 and 31.5%, P≤0.15) decreased with the harvesting age. It was concluded that in both harvesting seasons the mayority of the energetic and protein parameter decreased to increase the harvesting age of Kudzu.