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
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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 <0.05) degradability
of B and PD fractions of DM in the diet compared with the control. It could be concluded
that the inclusion of powder of leaves and twigs of Thymus schimperi plant up to an
optimum level of 16% feed can reasonably stimulate the growth and activity of the certain
rumen microbes that promoted an improvement in ruminal DM degradability of the diet
with the thyme inclusion. The results showed that inclusion of thyme in diet of dairy cows
resonbly at a level of 80g/day/head improved (P<0.05) dry matter(DM, OM, NDF, ADF
and estimated metabolisabl energy intakes compared to the control. The inclusion of
thyme in diet at lower level of 80g DM/day reasonably can improve (P<0.05) the DM, CP
and fiber (NDF and ADF) digestibility and it lowered (P<0.05) ruminal NH3-N
concentration, ruminal pH and temperature than the control. The Plasma glucose, urea,
creatinine, and triglyceride concentrations were fell within the normal values whereas the
values were declined (P<0.05) in the thyme supplementation group of cows compared to
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the control. Whereas, plasma total protein and globulin concentrations increased with the
thyme inclusion compared to the control. The serum alanine aminotransferase (ALT),
aspartate aminotrasferase (AST) and Gama glutamyl transferase (GGT) activities fell
within the physiological values but lower(P < 0.05) with inclusion of thyme compared to
the control group. The inclusion of Tossign leaves and twigs(TLT)at level of 80g/day/cow
in diet significantly (P < 0.05) reasonably could improve milk yield and yield of milk
components. The pH of raw milk and yogurt (Itittuu/Ergo) was not affected with the thyme
inclusion. The taste and flavor attributes of Itittuu of cows with dietary inclusion of TLT at
levels 80 and 160g/day/cow preferred more compared to the high level of thyme inclusion
(320g) and control. The dietary inclusion of thyme additive at level 80g/day/cow could be
considered an optimum level that improved (P < 0.05) the preference rate of apperance,
colour, consistency, aroma, taste, flvour and overall acceptability of cottage cheese of the
dairy cows as compared to the control in the present study. The inclusion of TLT in the
diet at a reasonable level of 80g/day/cow improved (P<0.05)the appearance, color,
texture/ consistency, aroma, and overall acceptability of butter of cross bred dairy cows
compared to control. The inclusion of the leaves and twigs of Thymus schimperi in ration
up to a level of 80g DM /day/cow represent an acceptable level to improve the sensory
properties of the milk and milk products for this study. Therefore, it is concluded that the
dietary inclusion of the powder of edible leaves and twigs of Thymus schimperi leaves and
twigs at a reasonble level of 80g/day/cow favourably modified rumianl activities, enhance
the apparent nutrient digestibility, and concomitantly improved the performances, product
qualities and health of lactating dairy cows.