عنوان مقاله [English]
Introduction: Fodder beet is a valuable source of fodder in livestock diets due to favorable agronomic characteristics such as resistance to salinity and drought, less water requirement, and proper nutritional characteristics such as forage production and silage with high nutritional value, good taste, and good resistance to environmental changes. Despite the long history of using fodder beet in animal rations, its nutritional issues and physicochemical properties of it are not fully understood and further research is needed. Silage of fodder beet can be used well in the diet of all ruminants, but studying the proper ways of silage and controlling the physical and chemical properties of silage is one of the important issues that should be addressed. In addition to the stated benefits for fodder beet, such as low dry matter content, fiber, and fat, disruption of ion exchange and change in silo buffering capacity, as well as the difficulty of processing it for permanent consumption of livestock and also important restrictions such as high sugar and moisture in the roots and excess leachate and lack of production of quality silage are the most important obstacles to the consumption of this silage. Harvest time of fodder beet coincides with the heat of the summer season and the occurrence of numerous problems, so it is necessary to silo it to prevent spoilage with the correct method. Today with the introduction of new improved cultivars and the growth of processing technology, these limitations have been almost removed. This study aimed to evaluate some of the physicochemical parameters of ensiled fodder beet with and without Lactobacillus buchneri as a microbial additive.
Materials and methods: Some physicochemical parameters of ensiled fodder beet with and without Lactobacillus buchneri as a microbial additive in combination with 10 and 15% dry beet pulp were investigated through a 3×2 factorial arrangement in four replicates. Different silages included: 1) 100% pure fodder beet without additive (control), 2) control + 10% dry beet pulp, and 3) control + 15% dry beet pulp. The microbial additive was added at the level of 6×1010 CFU/g of dry matter. 24 plastic bags containing 25 kg of different material were compacted, sealed, and stored at room temperature. After 75 days, four bags of each group were opened and pH, temperature, and quality were immediately determined. Also, a sample from each bag was used to measure the chemical compositions. Measurements of temperature and pH were performed. Two samples of silage, one for extraction and determination of ammonia nitrogen (using selective ion absorption electrode) by AFIA recommendations and the other sample for measurement of dry matter, crude protein, and ash according to the AOAC method were used. Measurement of NDF and ADF were done according to the Van Soest method. To evaluate the aerobic stability of silages when opening plastic bags, the characteristics of color, odor, and texture of silage in the range of 1 to 10 for high to poor quality were determined using the modified Konigsberg Scores method. Data were analyzed using a completely randomized design in a 3×2 factorial arrangement in four replicates using the mixed model procedure of the SAS program.
Results and discussion: Experimental groups with 10 and 15% of dry beet pulp with microbial additive had a better quality (score: 6.5±0.16 vs. 9.4±0.21; pH: 4.04±0.06 vs. 4.59±0.08) than the control group (P<0.01). The type of ensiled materials had a significant effect on chemical compositions (DM, CP, NDF, and ADF) and the aerobic stability of silages at opening time (P<0.01). But microbial additives almost had no significant effect on the traits. Watery loss of silage for the control group was higher and its quality was lower than that in other groups (P<0.01). The best quality and more stability of silage were observed in the group with fodder beet+15% of dry beet pulp which is advisable.
Conclusions: According to the results of this study, adding 10 and 15% of dry beet pulp to fodder beet silage improved the appearance and aerobic stability of the resulting silages compared to the control group. Evaluation of appearance traits and pH of the samples showed that the treatments with dry pulp and the microbial additive had better quality than the control group. The type of mixture used had a significant effect on the chemical composition of silage and its aerobic stability when opened, but the microbial additive did not show a significant effect in most cases. The watery loss in the control group was higher than the other treatments and had a worse appearance quality than other silages. Overall, the most suitable silage composition in this experiment was a mixture of the control group+15% sugar beet pulp, which had better appearance quality, longer shelf life, higher dry matter level, and lower ammonia nitrogen than the other two groups.