Two experiments were conducted to determine the nutritive value of commercially processed cottonseed meals (CSMS) in IRAN. In exp.1, CSMS were compared for chemical composition, and then were determind for nutrients digestibility and total digestible nutrient (TDN) by in vivo technique (total fecal collection method (TFCM) and marke in method (MM)) by taking into the experiment a total of four Afshari breed sheep. In exp.2, dry matter (DM) organic matter (OM) and crude protein (CP) degradability of CSMS were assessed by in situ technique for 2, 4, 6, 12, 24, 47 and 72 h in three ruminally canulated wether sheep. In order to determine the disappearance rates in 0 h, samples were washed using cold water. Sheep were fed a total mixed ration containing 70% alfalfa and 30% barley based concentrate. DM and CP were corrected for the particles loss from bags. A completely randomized design was used to compare parameters. In exp.1, CP and cell wall (NDF) in CSMS were 25.47 to 31 and 26 to 34 percent respectively. Chemical compositions of CSMS other than NDF, were lower than tabular values of National Research Council in TFCM, the differences between means of digestible CP, digestible crude fiber and TDN being significant (P<0.05). In MM, digestible CP and TDN were significant (P<0.05). There was a high correlation observed between the two methods. Differences between means of DM and CP degradability as well as CP degradability, corrected for the particle loss from bags, were significant (P<0.05). CSMS widely varied in their ruminal availability of CP and DM. This study provides an estimation of kinetics of ruminal degradation of cottonseed meals for use in dynamic models of protein and carbohydrate digestion.
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