USE OF A TROPICAL KUDZU (Pueraria phaseoloides) BANK AS SUPPLEMENTARY PROTEIN IN APARTIAL FEEDLOT SYSTEM OF FATTENING BULL DURING RAINY SEASON. LOS SANTOS, PANAMA. 1998.

Abstract

In Panama, the cost of the supplementary protein is high in partial feedlot systems of fattening cattle. Therefore, in order to reduce this cost, an experiment was carried out to evaluate the bioeconomical response to the partial sustitution of fish meal by Tropical Kudzu (Pueraria phaseoloides) as a legume bank. The experiment was performed during the rainy season, and two treatments (TR) were evaluated with a randomized design: Without Kudzu intake (TSK) and with Kudzu intake (TCK). The partial feedlot system consisted in grazing during the nigth and feedlot during the day ligth. Brachiaria decumbens was used with a rotation of 7 to 21 days of occupation and resting and N fertilization; it was grazing between 5:00 pm and 6:00 am. The Kudzu was grazed daily (4:00-5:00 pm) under a continuous occupation system. The supplementary feed consisted of molasses, fish meal, urea and a mineral mixture but in TCK the animals received only 50% of the fish meal corresponding to the TSK. Twenty one animals were utilized including Zebu and Zebu x Brown Swiss bulls, with an average age of 19 months (±4) and body weight of 310 kg (±38), which were kept under a health plan for controling internal and external parasites. Dry matter availability (DMA) and crude protein content (CPC) of B. decumbens were 2762 (±148) and 2379 (±158) kg/ha and 7.65 (±0.53) and 7.84 (±0.25)% for TSK and TCK, respectively. The grazing pressure (GP) did not vary too much between TR, with an average of 2.65 (±0.20) kg DM/100 kg body weight/day. The stocking rates (SR) were 6.45 (±0.10) and 9.02 (±0.26) animal units/ha for TSK and TCK, respectively. The legume bank presented a DMA, CPC, GP, SR and DM intake (kg/100 kg body weight/day) of 1815 (±99.5), 19.3 (±0.4), 0.87 (±0.02), 16.4 (±0.5) and 0.75 (±0.14), respectively. The ingestion of molasses and urea were the same for both treatments (1.12 and 0.02 kg DM/100 kg body weight/day) but the intake of fish meal were 0.088 and 0.038 kg DM/100 kg body weight/day for TSK and TCK, respectively. The ingestión of molasses and urea were the same for both treatments (1.12 and 0.02 kg DM/100 kg body weight/day) but the intake of fish meal were 0.088 and 0.038 kg DM/100 kg body weight/day for TSK and TCK, respectively. There was a significant effect of TR (P<0.001) on animal performance, with body weight gain of 0.857 (±0.020) and 0.639 (±0.017) kg/animal/day for TSK and TCK, respectively. With respec to TSK, the legume bank reduced the feed cost; however, it produced a lower income.