11 June 2013

6 minute read

Grazing cattle in the tropics present welfare issues as seasonal weather (wet and dry seasons) dramatically vary forage availability,. This is common in the neotropics but cattle researchers from the Department of Animal Production at the National Univeristy of Colombia has found that welfare benefits comes from silvopastoral grazing.

Popular across several Latin American countries, Intentive Silvo Pastoral ISS systems can sustain body condition and higher immune system efficiency, according to studies by Ariel Taronza, MariaCeballos, Cesar Cuartas Juan Naranjo, Enrique Murgueitio and Roland Rosales published by the Food and Agriculture Organisation.

Introduction

In Colombia, 70 per cent of cattle farms are extensive and characterized by low biological and economic efficiencies as a result of poor nutritional quality and lack of availability of pasture, especially during the dry season. This situation becomes more critical as grazing areas commonly show an advanced state of degradation with losses in biodiversity and of soil organic matter. This leads to cattle herds presenting low productive and reproductive rates and reductions in the profitability of the cattle business.

ISSs have proved to be a technological alternative that improve the competitiveness of livestock enterprises, and significantly improve the indicators of plant and animal production as management practices introduced as part of these systems make for more efficient livestock production.

Nutritional value of ISSs

The forage diet typically offered in the ISSs often contains high protein concentrations and digestibility (Table 1), a nutritional value similar to that of Medicago sativa, a highly valued forage. For ISS planted with leucaena, its low NDF may be associated with higher packing of the diet in the rumen and with an increase in dry matter intake, rate of passage and animal productivity.

Increases in animal production commonly reported with the adoption of ISSs are explained partly by leucaena’s condensed tannin content, which prevents excessive protein degradation in the rumen, allows proteins to be digested in the intestine and improves the quality of protein the animal receives. Reports indicate that tannins can reduce methane emissions in ruminants, promoting better use of consumed forage and improving the energy metabolism. Table 1 shows some nutritional characteristics of forages commonly used in ISSs arrangements.

El Hatic O, Natural Reserve of the Civil Society, Specialized Milk Production With Isss Under Tropical Dry Forest Conditions

El Hatico adopted silvopastoral systems in 1970 and has pioneered their use. This farm is located in the fertile flatlands of the Cauca River Valley in Colombia, at an altitude of 1 000 m, with an average temperature of 24 °C and an average of 800 mm of bimodal rainfall. Until 1970, the farm had conventional ranching practices: pastures with a few scattered trees (ten trees/ha), use of herbicides for weed control, irrigation in dry periods, chemical fertilization and a stocking rate below three cows/ha. In 1993, leucaena was planted at high density for browsing. Three years later, this family enterprise was awarded environmental certification.

The ISSs and rotational grazing systems used over the past 18 years have facilitated an increase in stocking rates to 4.3 dairy cows/ha and milk production by 130 per cent , without use of chemical fertilizers. El Hatico averages 3 030 L of milk per lactating period, for an annual production of 15 805 L/ha. The per cent age of fat in milk is 3.8 and that of protein is 3.25. The animal mortality rate is five per cent for the young and 0.5 per cent for adults, and the birth rate is estimated at 95 per cent , with a calving interval of 12.8 months and age at first calving of 30 months.

In the region, production of edible biomass for animals, which is highly dependent on the use of nitrogen fertilizer, is about 20 tonnes of DM/ha/year, while the ISSs produces about 30 per cent more biomass of higher nutritional quality (Table 2). Using grass, legume shrubs and trees in high density, it is possible to produce at least five times more milk and higher quality milk than in an open system without trees. In El Hatico, the area used for grazing in ISSs is 55 ha with a production of milk per hectare per year close to 16 000 litres; as a result, efficiency in land use is higher than in conventional farms. These results depend on proper management of grasslands.

The relationship between improved nutrition and enhanced animal welfare became evident in work recently carried out by the Center for Research on Sustainable Farming Systems (CIPAV) in different ISSs models including the model used in El Hatico. Because the results in animal welfare indicators are similar for all models tested so far in ISSs, they are presented in detail below. Briefly, animals in the ISSs spent more time foraging, had more cycles of consumption and rumination, and spent less energy in searching for forage, all of which are reflected in the maintenance of optimal body condition throughout the year. Other indicators of animal welfare as such as lying down, health and emotional status measured by qualitative behaviour assessment (Wemelsfelder, 2007), have shown higher rates of welfare when compared with conventional production models without trees.

El Chaco Farm , Beef Production With Isss Under Tropical Dry Forest Conditions

This farm is located on the terrace of Ibague, Tolima, at an altitude of 605 m and an average rainfall of 1 200–1 300 mm. The climate of the region corresponds to the life zone of tropical dry forest.

Animals used for fattening on this farm are Bos taurus x Bos indicus crosses. The breeding herd is mostly the product of Holstein x Gyr crosses with pure Guzerá and Brahman bulls, which transmit characteristics of resistance to heat stress and increased milk production.

Work at El Chaco has shown how in the upper Magdalena, by using leucaena and star grass, it is possible in 12 years to convert a farm with compacted soil, a stocking rate of 0.5 hd/ha, a calving interval of 15 to 18 months and an output of 120 kg of beef/ha/ year as weaned calves, to a farm that today has a stocking rate of 3.5 cows/ha, producing on average 10L of milk/cow (13 000 L/ha/year), with a calving interval of 14 months and weaning weights of calves at 10 months of age between 150 and 160 kg (more than 400 kg of beef/ha/year as weaned calves).

The productive results observed at El Chaco are explained by the characteristics of the system. The forage availability is 25 per cent higher than in systems without trees. Leucaena consumption reaches 30 per cent of the diet. In addition, our studies have shown that the consumption of forage in the ISSs is greater and the time spent on consumption is 17 per cent higher than in monoculture pasture systems, even at midday which corresponds to the hours of greatest brightness and highest daily temperatures.

The association between nutrition and animal welfare on the El Chaco farm is described briefly here. Animals in a pasture without trees do not consume forages during the midday hours when radiation and temperature reach their highest values, unlike the behaviour of consumption in ISSs in which animals show forage consumption cycles even at these times. The temperature differences in pastures without trees is up to 7 °C higher and may explain increased forage consumption in the ISSs where animals maintain thermal homeostasis and are more comfortable.

Conclusion

The ISS is a successful model of sustainable production in several Latin American countries. There is evidence that ISSs increase animal welfare through the improvement of nutrition, maintenance of optimal body condition, promotion of higher efficiency of the immune system and thus, improved health status, and that the ISSs provide conditions that help animals to cope better with environmental stressors.

Further Reading You can view the full report by clicking here.

June 2013