1. Production and economic potentials of cattle in pasture-based systems of the western Amazon region of Brazil. J. Anim. Sci. 81:2923-2937 Rueda, B.F., R.W. Blake, C. F. Nicholson, D.G. Fox, L.O. Tedeschi, A.N. Pell, E.C.M. Fernandez, J.F. Valentim, and J.C. Carneiro. 2003. Seasonal considerations of cattle nutrition management in tropical Latin America.

2. Brazilian cattle herd. 167 million animals ¼ reside in the Amazon region. Extensive systems. Milk from DP cows and beef from Nelore steers Typical pastures Brachiaria spp. Introduction

3. Objectives Evaluation of management strategies Evaluation of seasonal effects on nutritional values of B. decumbens and B. brizantha grasses and Pueraria phaseloides legume.

4. Characteristics Wet-tropic Region 1,800 mm rainfall November to March 25 ˚C average Temp 85% RH Ultisols & Oxisols pH 5.5 Low P content

5. The period of study was from the end of the 1999 dry season until the end of the subsequent rainy season in June 2000. Monthly monitoring of livestock productive performances under field conditions in order to establish a baseline milk and growth responses. Animal performance and environmental data were used as inputs for CNCPS simulations. Methodology

6. Cut 20 cm above the soil surface Swards of 80 cm height Paddocks grazed with 2 animal units/ha Biweekly grass samples Sampling close to the animal record- measurement day. (Milk production and BW) Hand plucking Forage sampling

8. Lactating cows = B. decumbens plus 10% kudzu to predict ME L & MP L Growing steers B. brizantha and finishing steers B. decumbens to predict gain in BW. Baseline

9. Baseline and alternative scenarios 25 or 50% greater productive performance 9 CNCPS simulation Supplementation was estimated Sorghum grain (85% TDN or 3 Mcal of ME/kg) Kudzu (18% CP) Potential of increased productivity

10. Increasing stocking rate from 2 to 4 au/ha Animals marketed 4 to 6 month earlier (BS) Additional inputs Supplements and labor Fertilizer, electric fences, etc Land Intensification options

11. ~ Milk production B. decumbens and kudzu, ranged from 5.4  0.26 kg/d (May) to 8.1  0.26 kg/d (December) ~ Weight gains were 0.5  0.02 kg/d for growing and finishing with B. brizantha. Finishing steers grazing B. decumbens gained 0.4  0.03 kg/d on average. Results

12. B. decumbens ~2,500 kg of DM/ha/mo B. brizantha ~ 3,500 kg of DM/ha/mo Forage was consumed from 20 cm of plants 85% leaves and 15% stems Lower stocking rate produced excessive accumulation of mature plant biomass Total Plant biomass accumulation

13. Less solubility for kudzu Grater availability of protein More microbial growth Similar nutritional value to other legumes However, B 2 fraction in grasses was digested more rapidly Excessive substitution of kudzu would decrease ME available for milk and growth

18. Higher stocking rate 65% net margins increased. Marginal rate returns of 1.55 4 au/ha Intensive grazing management is then the more profitable for both dual purpose cattle and beef. For Beef production

19. Chemical composition of grasses differed between rainiest and less rainiest seasons. B. brizntha provide more MP than B. decumbens to support lactation. Supplementation is needed during the moths with highest precipitation. Further research is needed. Conclusions

20. Importance of tree resources for dry season feeding and the impact of productivity of livestock farms. Pages 158-174 in Mannetje et al. (eds). The importance of silvopastoral systems in rural livelihoods to provide ecosystem services. Proc. 2nd Inter. Symp. Silvopastoral Syst. Yucatan, Mexico. Pp. 158- 174. Shelton, H.M. 2004. Seasonal considerations of cattle nutrition management in tropical Latin America.

21. Introduction Moisture Temperature Soil depth and fertility Radiation and day length Rainfall

25. Fodder tree for dry season Valuable as a dry season complement Drought tolerant CP content remains Variation on digestibility and DM

26. Increased intake of low quality feeds Anti nutritive constituents Tannins Antihelmintic properties Bypass protein

27. Reduce use of expensive concentrates 3 kg fodder = 1 kg commercial feed Ability to produce forage in the dry season Rooting depth Water use efficiency Drought tolerance

29. Large scale commercial systems Small scale systems  Alley crop production  Fodder banks  Cut-and-carry systems

30. Conclusions Tree legumes are particularly valuable during the dry season Tree legumes act as a protein supplement increasing intake. Secondary metabolites can reduce the rate of digestion of some proteins but also can reduce nematodes load. There can be options for small scale systems as well as large scale systems.