Effect of paddy straw plus nonforage fiber sources based complete rations with different levels of neutral detergent fiber on hemato-biochemical and mineral profile of lactating dairy cows

Aim: This study was conducted to assess the effect of feeding paddy straw plus nonforage fiber sources based complete rations with different levels of neutral detergent fiber (NDF) on hemato-biochemical and mineral parameters of lactating dairy cows. Materials and Methods: The study was conducted for 6 months in 18 lactating dairy cows, divided into three groups of six each, by feeding them on paddy straw plus nonforage fiber sources based complete rations containing different levels of NDF, in two phases of 3 months (90 days) each, being the early and mid lactation phases, respectively. Three isonitrogenous and isocaloric complete rations, T1, T2 and T3 with 25%, 30% and 35% NDF, respectively, were fed to the experimental animals. Blood samples were collected at the beginning and the end of each of the two phases to estimate the different hematological, plasma protein, and mineral parameters to know the overall health status of the animals and standard methods were followed to analyze the samples. Results: There was no significant difference (p>0.05) in various hematological parameters such as hemoglobin, glucose, and blood urea nitrogen (BUN) in blood; plasma protein parameters such as total protein, albumin, globulin and albumin: globulin ratio and mineral parameters such as plasma calcium and phosphorus levels at the beginning and end of Phase I (1st day and 90th day) and Phase II (91st day and 180th day) as well as between the three dietary treatments, with all the values being in the normal range for lactating dairy cows. Even though nonsignificant (p>0.05), the BUN values of animals fed on ration T1, both at the beginning and end of Phase I, were higher than that of animals fed on rations T2 and T3 because the diet T1 with lowest NDF and the highest soluble carbohydrate content underwent rapid fermentation in the rumen, produced more energy, which was utilized by the rumen microbes to degrade the protein in the feed to ammonia, the excess ammonia being transported to the liver and excreted through the blood resulting in a higher BUN content. Conclusion: Feeding of paddy straw plus nonforage fiber sources based complete rations with different levels of NDF had no effect on hemato-biochemical and mineral profile as well as overall health status of lactating dairy cows. However, the higher, BUN values found in cows fed on diet T1 with 25% NDF as compared to those fed on T2 and T3 with 30% and 35% NDF, respectively, indicate more wastage of protein in T1 as compared to T2 and T3, in early lactation.