Abstract:
The study was conducted to evaluate effects of dietary inclusion of Tossign (Thymus schimperi Ronninger) as natural feed additives in ration to modulate rumen fermentation and improve productivity of dairy cows. Eight multiparous early lactating crossbred (Holstein Fresian × Borana) dairy cows of parity two through five with similar live weight and milk production were selected for the study. Treatments were dietary inclusion of the powder of edible leaves and twigs of thyme (Thymus schimperi R.) in total mixed ration (TMR) of dairy cows at level o f 0 (T1), 80 (T2), 160(T3) and 320 (T4) g DM/day/cow. The experimental cows were randomly assigned to receive one of the four treatments in a double 4×4 Latin square design. The Thyme plant used for the study was collected from Dinsho and Tarmaber dstricts in highlands of Ethiopia. The chemical composition analysis and in sacco dry matter degradability (DMD) of Natural pasture hay (NPH), noug seed cake (NSC), wheat bran (WB) and total mixed ration (TMR) were determined by incubating without or with thyme substituting them at 8%, 16%, and 24% levels. The experiment diet was formulated to contain 15.53% crude protein (CP) and metabolizable energy (ME) of 10.5 MJ/kg DM to meet the requirements of the cows based on DMI and milk production immediately before the trial. The milk samples collected from each treatment and period were weighed and recorded every morning. Chemical composition of the milk samples were determined using standard procedure. Moreover, pH, sensory attributes of milk and its products were assessed. Ruminal contents were collected by using lubricated stomach tube connected to vacuum pump at the end of each treatment period just before feeding (0h) and 4h post-feeding for determination of ruminal parameters. Similarly, blood samples were taken from each cow from the jugular vein into a non-heparinized plain tube before feeding (0h) and 4hours after feeding for determination of sera metabolites. The result showed that chemical composition of all of the feeds differed significantly among treatments.The inclusion of TLT at rate 16% in natural pasture hay was improved fiber content of the diet. The organic matter(OM), acid xv detergent fiber(ADF) and acid detergent lignin(ADL) contents were higher with the inclusion of TLT at level of 16% in NSC. The DM, OM, and nutral detergent fiber(NDF) contents of WB were higher with the dietary inclusion of TLT compared to the control. The dietary inclusion of TLT at rate 8% to TMR lower the DM, OM and ADL ,and increased ash and cellulose contents of the ration. The in sacco DM degradability of NPH at all incubation hours was higher (P < 0.05) for 24% thyme inclusion level compared to the 0% and 8% levels.. The DM degradability of NSC was higher at lower level (8%) of inclusion of TLT in the diet for the majourity of the incubation hours. The DM degradability of WB was improved in with the inclusion of Thymus schimperi leaves and edinle twigs at rate 16% DM in this study. The higher in DM degradability of TMR with thyme inclusion at 16% DM was apparent during 24 to 72 hours of incubation. The slowly degradable fraction (B), potential degradability (PD), and effective degradability (ED) fractions for NPH were higher for the highest level of thyme inclusion than the other treatments.The ruminal degradabiltiy of B, PD and ED fractions in NPH was higher at 24% level of inclusion of thyme of the hay. The effective DM degradability value of noug seed cake was gradually increased as the level of inclusion of the additive plant was increased in this protein supplement. The lag phase(L) for NSC was increasing across the levels of thyme inclusion. The higher B fraction of WB was shown for the 8% thyme levels compared to control and the other thyme treatments levels.The dietary inclusion of TLT at a lower level (8%) in TMR resulted in higher (P