USE OF BYPRODUCTS FROM CORN INDUSTRY AND CITRIC ACID ON DAIRY HEIFERS DIET

Abstract Text: The use of byproducts in animal nutrition is an interesting alternative. Besides minimizing cost of livestock production, is a way to absorb part of the growing residue of industrial production, thus improving environmental conditions. Byproducts of sugar production, such as mycelium, precoat, and rafinate have become available for use. The mycelium is composed of cellular material from the fermentation of sugar by the fungus Aspergillus niger. The rafinate results from the purification process of the citric acid, the principal product formed from the fermentation of sugar. The precoat filter is derived from the step of glucose syrup production. The aim of this study was to evaluate performance of crossbred dairy heifers fed diets with wet byproducts. Forty heifers weighing on average 240 kg were randomly assigned to four treatments receiving control diet (n=10) and diets containing: precoat (n=10), mycelium (n=10) and rafinate (n=10). The control diet was formulated with sugar cane bagasse, and wet corn gluten feed (WCGF), corn gluten feed (CGF) and cracked corn. The other diets were formulated with the same ingredients, but with the inclusion of byproducts cited in their respective treatments. The average dry matter intake (DMI) was estimated by the difference between dry matter offered and orts, divided by the number of animals in treatment. Samples of offered and orts were collected daily and sent for chemical analysis. The design was randomized and analyzed variables were subjected to statistical analysis, considering significance at 5% probability. There were significant differences in dry matter intake (DMI) (P<0.01), where mycelium showed the highest and control the lowest intake. There were no significant differences in consumption of neutral detergent fiber by the animals, initial and final body weight, total and average daily gains and feed efficiency (FE) of the heifers (P>0.05). Control and rafinate groups showed better FE (P <0.01) compared to the mycelium, whereas precoat performed equally to all treatments. The inclusion of wet byproducts mycelium, precoat and rafinate in the diet of crossbred dairy heifers at 5.5, 3.4 and 4.8% of fresh matter, respectively, provides satisfactory performance of the animals. However, more studies are needed to determine the economic viability of using these byproducts in ruminant diet.

Keywords: mycelium, precoat, rafinate, dry matter intake