e effect of including ammoniated rice straw (ARS) to partia'ly replace clover

n lactating cows rations on their performance, milk yield and composition as

Dlood metabolites was investigated. Sixteen lactating Friesian cows with

body size (BW°75, kg) ranging from of 103 to 121 kg were used in this

animals were in the 2nd to 4th lactation season. Cows were randomly

into four groups (four animals each) and were randomly assigned for the

-zceimental diets. The experimental rations were formulated as follows: Rl:

50% corentrate feed mixture (CFM) + 50 % Clover hay (CH), R 2 : ration 2

CFM +10% CH+40 % ammoniated rice straw (ARS)., R 3: ration 3: 50 %

¿2% CH+30 % ARS., R 4 : ration 4 : 50 % CFM +50 % ARS. These

s were chosen to achieve approximately isonitrogenous ration containing

-15% CP. The experimental period lasted for 140 days (20 weeks).

e obtained results showed that total protein concentration of blood serum was

p < 0.05) 7.71 g/lOOml with Rl while lowest value (pc0.05) was noticed with

gIlOGml), but the difference between R2 or R4 was not significant. Globulin

tion was highest (p < 0.05) with Rl, while the lowest value (p < 0.05) was with

and 2.8 g/lOOml, respectively), but the difference between R2or R4 was not

t. The average daily fat corrected milk (FCM) yield was the highest (p < 0.05)

fed Rl or R2 (16.77 and 18.47 kg/d, respectively) compared with the other

The total solids (TS%), fat, lactose, protein, solids non fat (SNF%) and the

(NEL Mcal/kg milk) were not significantly different among treatments. The

n efficiency was improved with R2 (60.52%) compared with the other ones

worst value was noticed with the R3 (52.7%). .The highest value of feed cost

corded with Rl, but the lowest value with the R4. The highest value of the total

s the price of (FCM) was recorded with feeding R2, but the lowest value was

r.e R3. The results of return (profit L.E) , showed that the highest return was

when R2 was fed followed by R4 and the lowest was with R 1. Substitution of

nay by ammoniated rice straw at a level of at least 10% (DM basis) would

adequate fermentable N, as well as fermentable fiber, and above this level of

nay may not be necessary. The increase in DM intake when feeding on CH

might have affected fiber digestion because of an increase in the rate of

of digeste. The eNDF was higher when feeding on 10% clover hay + 40%

nar. the other ones. Such substitution resulted in improving milk production,

efficiency and economic efficiency.