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Poster 4.5: Silage of Cratylia Argentea as a dry-season feeding alternative in Costa Rica - P.J. Argel, M. Lobo di Palma, F. Romero, J. González, C.E. Lascano, P.C. Kerridge and F. Holmann

P.J. Argel*, M. Lobo di Palma, F. Romero, J. González, C.E. Lascano, P.C. Kerridge and F. Holmann.

*CIAT Consultant
Apartado 55-2200 Coronado

San José, Costa Rica

E-mail: [email protected]


The legume Cratylia argentea (syn. C. floribunda, Dioclea floribunda), which occurs naturally south of the Amazon river through the area east of the Andes in Brazil, Peru, Bolivia and Argentina, is a shrub that branches from the base of the stem and reaches 1.5 to 3.0 m in height (De Queiroz and Coradin, 1995). It is well adapted to subhumid climates with a five- to six-month dry season and infertile acid soils with high aluminium content in tropical areas below 1 200 m above sea level.

Germplasm of C. argentea has shown good regrowth capacity after cutting, and adaptation to biotic and abiotic constraints in several lowland sites in tropical America (Isla in Mexico, La Ceiba in Honduras, and several sites in Costa Rica, Colombia and Brazil), and in West Africa (CIAT, 1995). CIAT together with national agricultural research systems have carried out studies on management and feed value of Cratylia in the region. Results indicate that yield of Cratylia fodder banks is increased when plant density is at least 20 000 plants/ha. As expected, digestibility (50-60%) and CP (20-25%) vary with plant part and maturity. Intake of fresh material is increased when Cratylia is cut and wilted, given that direct animal intake of freshly harvested immature Cratylia forage is low (Raaflaub and Lascano, 1995).

The value of Cratylia as a cut-and-carry protein supplement with sugar cane or king grass fed during the dry season to lactating dairy cows is being evaluated in smallholder dual-purpose cattle farms in Costa Rica (Argel and Lascano, 1998). In addition, farmers are currently evaluating the option of utilizing for ensiling excess Cratylia forage produced in the wet season.

In this paper, we present results from the on-station and on-farm evaluations of Cratylia when used as silage to supplement milking cows in the dry season.


Ensiling Cratylia is a farmer-based initiative and consequently researchers in Costa Rica are now in the process of producing information for farmers in order to allow them to make good quality silage with this legume. Farmers testing the use of Cratylia for silage have developed their own system of harvesting and ensiling the harvested forage. Leaf and stem material from three- to four-month regrowth is cut and mechanically chopped into 2-5 cm pieces. Harvested material is then placed in stack-type silos and after good compaction is covered with plastic sheeting. Molasses is added when ensiling pure Cratylia (10-15% DM basis), while a silage inoculum is added in a proportion of 1 kg/ton of silage when mixed with King grass (30:70 proportion of legume:grass silage).


In areas with a five- to six-month dry season in Costa Rica, there is a need to supplement dairy cows with concentrates or chicken manure to maintain acceptable levels of milk production. However, farmers are looking for alternatives, as grain imports are becoming too expensive and milk prices are decreasing. An alternative considered by farmers in order to reduce supplementation costs is to replace concentrates and chicken manure by fresh or ensiled Cratylia fed in combination with sugar cane or king grass during the dry period.

An initial experiment was carried out in the Escuela Centroamericana de Ganaderia (ECAG), Atenas, Costa Rica (460 m above sea level, annual mean temperature 23.7°C, mean annual precipitation 1 600 mm). Six mature Jersey cows (50 days postpartum) were randomly assigned to the following treatments arranged in a 3 × 3 crossover Latin Square design:

- T1 = sugar cane (1.0% BW) + rice polishings (0.5% BW) + concentrate (1.48% BW) + urea (0.02% BW);

- T2 = sugar cane (1.3% BW) + concentrate (0.5% BW) + freshly cut C. argentea (1.2% BW); and

- T3 = sugar cane (0.1% BW) + concentrate (0.5% BW) + silage of C. argentea (2.4% BW).

Each treatment period comprised 12 days, of which 7 were for adaptation and 5 for measurement. Concentrate (0.5% BW) was fed with the Cratylia treatments as cows used in the experiment were accustomed to receiving some concentrate during milking.

Results, shown in Table 1, indicate that milk yield in cows supplemented with concentrate was similar to that from cows supplemented with Cratylia, fresh or ensiled. However, it was interesting to observe that milk fat was greater in cows fed Cratylia silage. The higher cost and lower benefit:cost ratio of feeding Cratylia silage were due to high labour cost in ECAG for harvesting and separating edible portions of six-month old Cratylia regrowth, which is not the case for farms, as indicated in a subsequent on-farm trial.

Table 1. DM intake and milk production by Jersey cows fed different diets during the dry season in Costa Rica


DM intake

Milk yield




Cost of supplement
($/kg DM) (1)

Benefit:cost ratio

T1 - Concentrate








T2 - Fresh Cratylia








T3 - Cratylia silage








Significant Diff.(2)








Notes: (1) Includes the cost of all ingredients in the supplement except sugar cane. (2) Ns = not significant.

Source: F. Romero and J. Gonzalez, unpublished data.

One farmer in the Central Pacific subhumid coast area of Costa Rica evaluated with the assistance of researchers the use of Cratylia as silage. Six cross breed Swiss Brown × Brahman dual-purpose cows in the third month of lactation were assigned to the following treatments arranged in a 3 × 3 cross-over Latin Square design:

- T1 = 12 kg sugar cane + 6 kg C. argentea silage + 0.6 kg rice polishings;

- T2 = 12 kg sugar cane + 6 kg C. argentea fed fresh + 0.6 kg rice polishings; and

- T3 = 12 kg sugar cane + 3 kg chicken manure + 0.6 kg rice polishings.

The results shown in Table 2 corroborate on-station results, namely little difference in milk yield, but higher milk fat when chicken manure was replaced by Cratylia silage. Results also indicate that the cost of supplementation was lower when Cratylia was fed fresh or ensiled, which resulted in higher economic benefit for the farmer when compared with use of chicken manure.

Table 2. Average milk yield of dual-purpose cows supplemented with Cratylia either fresh or as silage and with chicken manure


Milk yield

Total solids


Cost of supplement
($/kg DM)

Benefit:cost ratio

T1 - Cratylia silage

5.1 b





T2 - Fresh Cratylia

5.5 a





T3 - Chicken manure

5.3 a b





Notes: a and b indicate significant differences.

Source: M. Lobo, V. Acuña and A. López, unpublished data


The use of Cratylia argentea for making silage has been a farmer-led initiative in dual-purpose cattle farms in hill areas of Costa Rica. On-farm use of Cratylia silage as a supplement to milking cows has been shown to be a viable option for small-scale dairy farmers, given that it economically replaces expensive concentrates with no effect on milk yield, but gives a higher percentage milk fat yield. Research is underway to better define ways of producing high quality Cratylia-based silage.


Argel, P.J., & Lascano, C.E. 1998. Cratylia argentea (Desvaux) O. Kuntze: Una nueva leguminosa arbustiva para suelos ácidos en zonas subhúmedas tropicales. Past. Trop., 20: 37-43.

CIAT. 1995. West and Central African animal feed research project Adaptation of Forages in West Africa. Working Document No.145. CIAT, Cali, Colombia.

De Queiroz, L.P., & Coradin, L. 1955. Biogeografia de Cratylia e Areas Prioritárias para Coleta. p. 1-28, in: E.A. Pizarro & L. Coradin (eds) Potencial de Género Cratylia como Leguminosa Forrajera. Memorias del taller de Trabajo sobre Cratylia realizado el 19 y 20 de julio de 1995, Brasilia, DF, Brazil. Working Document No. 158. CIAT, Cali, Colombia.

Raaflaub, M., & Lascano C.E. 1995. The effect of wilting and drying on intake and acceptability by sheep of the shrub legume Cratylia argentea. Trop. Grassl., 29: 97-101.

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