The Effect of Different Levels of De-oiled Rice Bran Replacement to Soybean Meal on Milk Production and Composition, Body Condition Score and Some Blood Parameters in Dairy Cows

The use of agricultural products that are often less costly has long been considered by researchers, and due to some problems with the direct use of these products in animal nutrition, their processing seems to be necessary in a variety of ways. In the meantime, by-products derived from cereals, such as wheat bran and rice bran, are especially important due to their high production and low prices. Rice bran can be one of the world's largest cereal processing by-products. Considering the significant amount of rice bran production in the northern provinces of Iran, its low price and the possibility of replacing it as part of the ration and, on the other hand, due to the presence of unsaturated oil, it seems that its lubrication It will probably increase the maintenance time and improve its nutritional value. The main problem is the use of rice bran, phosphate phytate, oil and high silica. Considering the significant amount of rice bran production in the northern provinces of the country, its low price and the possibility of replacing it as part of the ration and, on the other hand, due to the presence of unsaturated oil, it seems that its lubrication It will probably increase the maintenance time and improve its nutritional value. The objective of this study was to evaluate the different levels of de-oiled rice bran replacement to soybean meal on milk production and composition, the profile of fatty acids in milk, body condition score and some blood parameters of dairy cows.

An experiment was conducted using 12 of Simmental dairy cows with a mean weight of 630±27 kg, a mean milk yield of 35±1.7 liters per day and an average of 109±17  days of lactation in a completely randomized design with four treatments and three repetitions. The experimental treatments were included control diets without de-oiled rice bran and diets containing de-oiled rice bran replacing 50, 75 and 90% to soybean meal. The diet used was based on the table of nutrient requirements of NRC, (2001) and the diet was prepared by the NRC, (2001) software. The traits studied in this experiment included milk composition and production, body condition score, profile of milk fatty acids and some blood serum parameters of dairy cows. The oil-rice bran used in this experiment was prepared from Mazand factory, located in Mazandaran province, Babolsar city. The data were collected and experimental design was a completely randomized design with four treatments and three replicates using 12 heads of dairy cows with repeat measurement and using the GLM and SAS software (9.1).

 The experimental results showed that the experimental diets had a significant effect on the composition and production of milk, so that the production of milk in a treatment containing de-oiled rice bran replaced with 75% soy meal was more than other experimental treatments. The percentage of milk protein in a treatment containing de-oiled rice bran replaced with 50% soy meal was more than other experimental treatments. Also, the results showed that the highest percentage of milk fat in the control treatment and the lowest milk fat in the treatment of de-oiled rice bran was replaced with 75% soybean meal, which had a significant difference with other treatments. There was no significant difference in the number of somatic cells between treatments. Body condition scores were no significantly affected by experimental diets. The effect of treatments on milk fatty acids was not significant. Also, the addition of de-oiled rice bran had a significant effect on blood parameters, so that by increasing the level of rice bran in the diet, up to 75% of the soybean meal replaces a significant decrease in blood levels other than glucose. In addition, the control treatment had the highest levels of triglyceride and cholesterol and the amount of HDL in treatment containing de-oiled rice bran replaced with 75% soy meal was significantly higher than other treatments.

According to the results of this experiment, the use of 75% of de-oiled rice bran replacement to soybean meal in the diet, increased milk yield and reduced fat percentage in dairy cow compared to control treatment. Also, the reduction of cholesterol, triglycerides and HDL levels in dairy cows were observed treatment containing de-oiled rice bran replaced with 75% soy meal. It seems that the use of 75% of de-oiled rice bran replacement to soybean meal in the diet, showed better performance than the other levels in the production factors of dairy cows in this study.