Browsing by Author "Russell, JR"

Now showing 1 - 3 of 3

Effects of Some Dietary Factors on Ruminal Microbial Protein Synthesis
(Scientific Technical Research Council Turkey, 2001) Karsli, MA; Russell, JR
The effects of some dietary factors, other than source and amount of N and carbohydrate, on the amount and efficiency of microbial protein synthesis are discussed in this review. Specifically, these factors include dry matter intake of animals, forage: concentrate ratio of diets, rate of N and carbohydrate degradation, synchronized release of N and energy from diets, rate of passage, and other factors, such as vitamins and minerals. It seemed that diets containing a mixture of forages and concentrates increase the efficiency of microbial protein synthesis because of an improved rumen environment for the growth of more diverse bacteria species.
Effects of Source and Concentrations of Nitrogen and Carbohydrate on Ruminal Microbial Protein Synthesis
(Scientific Technical Research Council Turkey, 2002) Karsli, MA; Russell, JR
The objective of this review was to discuss microbial protein synthesis and the effects of sources and concentrations of nitrogen and carbohydrate on microbial protein synthesis. Even though ammonia-N is a satisfactory source of nitrogen for the growth of the majority of rumen microbes, substitution of intact protein for urea usually stimulates ruminal microbial protein synthesis. While protein sources high in degradable intake protein (DIP), such as soybean meal, appear to have properties that optimize microbial protein synthesis, protein sources low in DIP, such as fish meal, appear to limit microbial protein synthesis apparantly because of the low ruminal digestibility of fish meal. Similarly, a mixture of structural and non-structural carbohydrate sources is necessary for maximal microbial protein synthesis in the rumen.
Prediction of the Voluntary Intake and Digestibility of Forage-Based Diets From Chemical Composition and Ruminal Degradation Characteristics
(Scientific Technical Research Council Turkey, 2002) Karsli, MA; Russell, JR
Two digestion experiments and an in situ nylon bag experiment were conducted to determine the correlations between chemical composition, ruminal in situ degradation kinetics and OM I, and OM and CP digestibilities of diets in wethers fed forages of varying nutritive value without and with protein supplementation. Wethers were fed ground corn crop residues, oat-berseem clover or alfalfa hay in the first experiment, ground corn crop residues with or without alfalfa or oat-berseem clover hay supplemented with SBM and grain corn mixture to meet the DIP requirement, by using level 1 of the Nutrient Requirements of Beef Cattle computer program at ad libitum intake. To determine the kinetics of N and OM degradation in the rumen, a composite sample of each feed was prepared. Duplicate bags of each forage were attached to weighted rings, placed in the rumens of two fistulated steers grazing smooth bromegrass, and allowed to incubate for 0, 3, 6, 12, 24. 48 and 72 h. While the concentrations of NDF and ADF and the percentage of potentially digestible organic matter fraction and indigestible organic matter fraction were greater, the percentage of water soluble organic matter fraction was lower in corn crop residue compared with alfalfa hay or oat/berseem clover (P<0.05). Addition of alfalfa or oat-berseem clover hay supplemented with SBM and grain corn mixture to corn crop residues linearly decreased the concentrations of NDF and ADF, and the percentage of the indigestible organic matter fraction, but increased the percentage of potentially digestible and water soluble organic matter fractions. Organic matter intake, organic matter and crude protein digestibilities were significantly lower (P<0.05) in wethers fed corn crop residues alone compared with wethers fed alfalfa or oat/berseem clover hays. Addition of protein supplement sand addition of increasing levels of oat/berseem clover or alfalfa hays to corn crop residues linearly increased organic matter intake, organic matter and crude protein digestibilities of diets in wethers. The highest correlations were observed between water soluble organic matter fraction and organic matter intake (r(2) = .80), ADF and apparent total track OM digestibility (r(2)=.94), and indigestible CP fraction and true ruminal CP digestibility (r(2)=.82). It was concluded that chemical composition with ruminal degradation characteristics can provide a reliable prediction of the intake and digestibility of forage-based diets.