Digestibility and consumption of low quality hay and soybean straw. Effect of soybean protein supplementation.

LABORDE, H.E.; BREVEDAN, R.E.; FIORETTI, M.N.; BAIONI, S.S.

Bhopal, India

Conferencia; International Soybean Procesing and Utilization Conference (ISPUC-V 2008).; 2008

  World demands for high quality protein have increased soybean production in Argentina. At the present time soybean harvested almost 47,2 million tons, half of the total grain production of the country. The determination of the nutritional value of soybean straw is needed because the expansion of soybean production is a recent event and there is a need of it in several regions of the country for the maintenance of livestock. Soybean straw is a major by-product, thus providing an alternative to the typically low quality pastures and hays. The production of soybean protein along with that of cereal grain calls for an evaluation of legume and cereal grain straws as animal feedstuffs. The semiarid region around Bahía Blanca (38° 44’S 62° 15’W) has a mixed production system based on winter crops (mostly wheat) and an extensive cattle-breeding on natural grassland and hay. Here there is a dependence on low quality forages. Crop residues, especially those of soybeans are an important alternative, which should be utilized as much as possible, particularly in a year when feed supplies are limited. Despite limitations as seasonality, cost of harvest and low digestibility, the potential for using crop residues to increase efficient beef production is very important. The straw obtained from thrashing the soybean for seed is a valuable feed for all kinds of livestock. Legume straws tends to be higher in protein (7-8% crude protein), contain much higher levels of Ca and P than do cereal straws and also has a high fibre content. When livestock is forced to use mature forage, nutrient deficiencies may be expected and it has to be supplemented. Even though the soybean grain production is allocated to industrialization or exportation, the farmer kept small and broken grains that are rejected. This soybean seed or “sojilla”, that also include pieces of stem and weed seeds, is an excellent protein supplement. The objectives were: 1) to evaluate the effect of whole soybean grains and “sojilla” to supplement wheat straw, and 2) to study the intake and digestibility of soybean straw. Nutritive value was estimated on field grown plants and plant parts by using standard techniques of forage chemical analysis and IVDMD. Analysis of cattle blood parameters like mineral concentration and esterified fatty acids were determined. Results of the experiments will be presented at the Conference.