Livestock Research for Rural Development 22 (6) 2010 Notes to Authors LRRD Newsletter

Citation of this paper

Evaluation of rations supplemented with fibrolytic enzyme on dairy cows performance 3. Productive performance of lactating Friesian cows

M I Bassiouni, H M A Gaafar*, A M A Mohi El-Din*, A M Metwally and M A H Elshora*

Department of Animal Production, Faculty of Agriculture, Kafrelsheikh University, Egypt
* Animal Production Research Institute, Agricultural Research Center, Dokki, Giza, Egypt
dr.gaafar@hotmail.com

Abstract

Thirty multiparous lactating Friesian cows with body weight of 500ą25 kg were used during the first 20 weeks of lactation. Cows were randomly assigned to six similar groups (5 in each) and fed the experimental rations consisted on DM basis of 60 % concentrate feed mixture (CFM) + 40 % berseem hay without  (BH) or with fibrozyme (BH-E), corn silage without  (CS) or with fibrozyme (CS-E) or rice straw without  (RS) or with fibrozyme (RS-E). Fibrozyme was added at level of 1 g/kg DM.

 

Results showed that cows fed ration containing CS-E showed the highest DM and TDN intake and those fed ration based on BH-E had the highest DCP intake,  those fed ration containing RS recorded the lowest intake (P<0.05). The BH-E ration showed the highest digestibility coefficients of DM, OM, CP and CF and DCP value, while CS-E the highest EE digestibility and TDN value.  

 

Cows fed CS-E ration had significantly (P<0.05) the lowest pH value and the highest TVFA's concentration, while those fed BH ration revealed the highest NH3-N concentration. The pH value decreased, but TVFA's and NH3-N concentrations increased gradually until 4 hours after feeding then showed opposite trend at 6 hours.

 

Cows fed CS-E ration recorded significantly (P<0.05) the highest actual milk and 4% FCM yield and the percentages of fat, lactose and TS in milk, while those fed BH-E had the highest protein and SNF percentages (P<0.05).

 

Cows fed CS-E recorded the lowest requirements of DM and TDN per kg FCM, while those fed RS-E showed the lowest DCP/ kg FCM (P<0.05). Cows fed RS ration revealed the lowest average daily feed cost, wile those fed CS-E recorded the lowest feed cost/ kg FCM and the highest income of FCM and economic efficiency.

Keywords: digestibility, economic efficiency, feed conversion, milk yield and composition, rumen activity


Introduction

In the different regions of the world, forages are used as a unique feed source for ruminants due to their abundance and low cost. However, their availability and quality are not constant throughout the year. Moreover, the digestion of forages in the rumen is relatively slow and incomplete, limiting animal performance and increasing feed cost of livestock production. Tropical forages in particular have limited energy value and its cell wall contents are rich in lignin, silica and that limit carbohydrate fermentation and therefore the VFA production and microbial mass in the rumen (Dominguez Bello and Escobar 1997).

 

Recent studies indicated that, adding fibrolytic enzymes to ruminant diets improved nutrient digestibility (Kung et al 2000 and Murillo et al 2000), growth rate (Ali 2006) and milk production (Rode et al 1999 and Zheng et al 2000). Moreover, fibrolytic enzymes were more effective when added to either concentrate or roughage portion of diets in early lactation period. These enzymes increased milk yield by 6 to 16% in Lactating dairy cows (Lewis et al 1999; Yang et al 2000). Furthermore, enzyme application was more effective with lower forage to concentrate ratio (38:62) than higher ratios (55:45, 57:43 and 60:40). Therefore, the effect of the dietary component to which the enzyme is added may depend on the forage to concentrate ratio and the uniformity of enzyme application to these components (Adesogan 2005).

 

Beauchemin et al (2003) indicated that using fibrolytic enzymes improves forage utilization and productive efficiency of ruminants and, adding enzymes to high-concentrate diets gave more consistent results than with high-roughage diets. They also found that, improvement in animal performance due to enzyme additives could be attributed mainly to improvements in ruminal fiber digestion resulting in an increase of digestible energy intake.

 

Ruminal pH plays an important role in fiber digestion, because the growth of ruminal fiber digesting bacteria is strictly limited at pH less than 6.00 (Russell and Wilson 1996) who hypothesize that the relative magnitude of the benefit to enzyme supplementation is a least partially dependent on ruminal pH (Murillo et al 2000).

 

Dairy cows fed forage treated with a fibrolytic enzyme additive ate more feed and produced 5 to 25% more milk (Lewis et al 1995; Stokes and Zheng 1995). The beneficial effects of fibrolytic enzymes in ruminant diets appear to be a result of, in part, improvements in feed digestibility (Beauchemin et al 1995,1999, Feng et al 1996, Lewis et al 1995; Yang et al 1999). If exogenous feed enzymes increase the digestibility of the diet, the beneficial effects on animal performance are likely to be greatest for ruminants in negative energy balance, such as cows in early lactation.

 

The objective of the present study was to investigate the effect of fibrolytic enzyme (Fibrozyme) additive on feed intake, digestibility, milk production and composition, rumen fermentation, feed and economic efficiency of lactating Friesian cows.

 

Materials and methods 

Experimental animal and rations

 

Thirty multiparous lactating Friesian cows with body weight of 500ą25 kg were used during the first 20 weeks of lactation. Cows were randomly assigned to six similar groups (5 in each) and fed the experimental rations consisted on DM basis as follows:

BH    : 60% concentrate feed mixture (CFM) + 40% berseem hay (BH) without enzyme.

BH-E: 60% CFM + 40% BH with 1 g enzyme / kg DM.

CS    : 60% CFM + 40% corn silage (CS) without enzyme.

CS-E: 60% CFM + 40% CS with1 g enzyme/ kg DM.

RS    : 60% CFM + 40% rice straw (RS) without enzyme.

RS-E: 60% CFM + 40% RS wit1 g enzyme/ kg DM.

Fibrolytic enzyme (fibrozyme) ingredients are Aspergillus niger, Trichodema longibrchiatum, fermentation extracts and fermentation solubles. Also, it contains 20% CP, 8% ash and 100 U xylanase / g (International Free Trade Co., Cairo, Egypt). The fibrozyme was added to the feedstuff at the level of 1 g/kg DM, diluted with water at 100 g/liter and sprayed with 10 ml per kg of feedstuffs according to the procedure stated by Kung et al (2000).

 

Cows were individually fed the experimental rations to cover the recommended requirements for dairy cows according to NRC (2001). Feeding allowances were adjusted every week according to changes in body weight and milk production. Concentrate feed mixture was fed in two equal meals daily at 8 a.m. and 4 p.m., while berseem hay, corn silage or rice straw was fed once daily at 10 a.m. Cows were watered three times daily at 7 a.m., 1 and 7 p.m.

The total duration of the trial was 20 weeks.

 

Milk yield and sampling

 

Individual cows were milked mechanically, morning and evening milk yields were recorded daily for each cow and the 4% fat corrected milk (FCM) for each cow was calculated from daily milk yield and the percentage of milk fat using the formula given by Gains (1928) as follows: 

 

 4% FCM = [0.4 X milk yield (kg)] + [15 X fat yield (kg)].

 

Milk samples were taken biweekly from the consecutive evening and morning milking for each cow and mixed in proportion to milk yield.  Composite milk samples were analyzed for fat, protein, lactose, solids not fat (SNF), and total solids (TS) by milko scan, model 133B.

 

Digestibility trials

 

Six digestibility trials were carried out during the feeding trial using three cows from each group to determine the nutrients digestibility coefficients and nutritive values of the experimental rations using acid insoluble ash (AIA) as a natural marker (Van Keulen and Young 1977). Feces samples were taken from the rectum of each cow twice daily with 12 hours interval during the collection period (last week of experiment). Samples of tested rations were taken at the beginning, middle and end of collection period. Samples of tested rations and feces were dried in a forced air oven at 60 oC for 48 hours, then pooled for each animal, ground and chemically analyzed according to the methods of AOAC (1990). Nutrient digestibility coefficients and nutritive value was calculated from the equation stated by Schneider and Flatt (1975).

 

DM digestibility (%) = 100 – [100* AIA % in feed/ AIA % in feces]

Digestibility (%) of proximate analysis components = 100 – [100*AIA % in feed *component % in feed/ AIA % in feces* component % in feces]

 

Rumen liquor samples

 

Rumen samples were collected from the cows using a rubber stomach tube connected withdrawal plus power of the automatic milking machine. Samples were collected three times during the experimental period at 0, 3, 6 hours after the morning feeding. Every sample was strained through four layers cheesecloth. Ruminal pH value was determined directly, ammonia–nitrogen concentration was determined by using magnesium oxide (MgO) as described by AOAC (1990). Total volatile fatly acids (TVFA's) were determined by steam distillation method as described by Warner (1964).

 

Feed conversion

 

Feed conversion was determined as the amounts of DM, TDN and DCP required for producing 1 kg 4% FCM.

 

Economic evaluation

 

Economic efficiency was calculated according to the following formula:
 

Where: price of 1 tonne concentrate mixture = 1600 LE, berseem hay = 800 LE, rice straw = 100 LE, corn silage = 150 LE, fibrozyme = 10 LE/kg and FCM = 2 LE/ kg.

 

Statistical analysis

 

Data were subjected to statistical analysis using general linear models procedure adapted by SPSS for windows (2004) for user’s guide with one-way ANOVA. Duncan test within program SPSS was done to determine the degree of significance between the means (Duncan 1955).

 

Results and discussion 

Chemical composition of experimental rations

 

Calculated chemical composition of experimental rations is shown in Table 1.


Table 1.  Chemical composition of  feedstuffs and experimental rations

Item

Feedstuffs

Experimental rations

CFM*

BH

CS

RS

BH

CS

RS

DM %

91.5

89.9

33.9

91.6

90.8

54.5

91.5

Composition of DM, %

OM

91.8

85.6

92.3

82.8

89.3

92.0

88.2

CP

16.1

13.5

8.75

3.01

15.0

13.1

10.8

CF

12.3

31.3

26.3

35.7

19.9

17.9

21.6

EE

2.98

2.25

2.56

1.25

2.69

2.81

2.29

NFE

60.5

38.7

54.7

42.8

51.8

58.2

53.4

Ash

8.52

14.4

7.69

17.3

10.7

8.03

11.9

Fiber fractions, % of DM

NDF

26.9

46.8

55.4

74.6

34.9

38.3

46.0

ADF

12.3

27.2

28.4

44.9

18.2

18.7

25.3

ADL

3.76

4.83

5.20

3.12

4.19

4.34

3.50

Hemicellulose

14.6

19.6

27.0

29.7

16.7

19.6

20.7

Cellulose

8.49

22.4

23.2

41.8

14.0

14.4

21.8

* CFM consisted of 32% undecorticated cotton seed cake, 24% wheat bran, 22% yellow corn, 12% rice bran, 5% linseed cake, 3%molasses, 1% limestone and 1% common salt


 Results revealed that CP content was higher in rations contained BH, NFE content was higher in rations contained CS and CF and fiber fractions contents were higher in rations contained RS. These results reflect the chemical composition of concentrate feed mixture, berseem hay, corn silage and rice straw.

 

Feed intake

 

Effect of roughage type and fibrozyme supplementation on average daily feed intake is shown in Table 2.


Table 2.  Average daily feed intake (kg/head) by Friesian cows fed experimental rations

Item

Intake as fed

Intake as DM

CFM

BH

CS

RS

Total

DM

TDN

DCP

Type of roughage

BH

10.7b

7.23

-

-

17.9b

16.2a

10.3b

1.70a

CS

11.0a

-

19.7

-

30.7a

16.7a

11.0a

1.55b

RS

10.0c

-

-

6.62

16.6c

15.2b

9.0c

1.10c

ąSEM

0.10

 

 

 

1.19

0.20

0.19

0.05

P-value

0.015

 

 

 

0.021

0.017

0.013

0.006

Enzyme supplementation

Without

10.4

2.39

6.53

2.19

21.6

15.9

9.73

1.39

With

10.6

2.43

6.61

2.22

21.9

16.2

10.5

1.51

ąSEM

0.10

0.63

1.73

0.58

1.19

0.20

0.19

0.05

P-value

0.452

0.977

0.982

0.978

0.902

0.579

0.061

0.276

Interaction (roughage x enzyme)

BH

10.6a

7.17

 

 

17.7b

16.1abc

9.85b

1.62b

BH-E

10.7a

7.28

 

 

18.0b

16.4abc

10.7a

1.78a

CS

10.9a

 

19.6

 

30.5a

16.6ab

10.6a

1.50c

CS-E

11.0a

 

19.8

 

30.9a

16.8a

11.3a

1.60bc

RS

10.0b

 

 

6.57

16.4c

15.0c

8.69c

1.07d

RS-E

10.0b

 

 

6.67

16.7c

15.3bc

9.33bc

1.14d

ąSEM

0.10

 

 

 

1.19

0.20

0.19

0.05

P-value

0.032

 

 

 

0.046

0.036

0.016

0.008

a, b, c, d Values in the same column for each item with different superscripts differ significantly at 5% level


Cows fed ration contained CS  recorded the highest DM and TDN intake and those fed ration contained BH  had the highest DCP intake, however, those fed ration contained RS  showed the lowest intake of DM, TDN and DCP (P<0.05). Moreover, the intake of TDN increased significantly (P<0.05) with fibrozyme supplementation. The interaction between roughage and enzyme supplementation revealed that cows fed CS-E recorded the highest DM and TDN intake and those fed BH-E had the highest DCP intake (P<0.05). These results agreed with those obtained by Pinos-Rodriguez et al (2002) who found that feed DM intake by lambs was not affected by enzyme. Bowman et al (2002) reported that DM intake was not significantly altered, but digestible DM intake increased significantly by inclusion of enzyme. The intake of DM by cows fed rations contained RS tended to lower than the recommended requirement, while the intake of TDN and DCP by cows fed rations contained BH and CS were higher than the recommended requirements (NRC 2001).

 

Digestibility coefficients

 

Digestibility coefficients of experimental rations by cows are presented in Table 3.


Table 3.  Digestibility coefficients and nutritive values by Friesian cows fed experimental rations

Item

Digestibility coefficients %

Nutritive values %

DM

OM

CP

CF

EE

NFE

TDN

DCP

Type of roughage

BH

66.0a

68.6a

69.7ab

67.6a

62.5b

68.9

63.3a

10.47a

CS

65.0ab

68.7a

70.5a

66.7a

71.7a

68.7

65.7a

9.26a

RS

62.6b

65.6b

67.1b

57.2b

56.1c

69.1

59.5b

7.28b

ąSEM

0.57

0.56

0.61

1.21

1.41

0.30

0.88

0.35

P-value

.038

0.037

0.053

0.014

0.010

0.850

0.010

0.001

Enzyme supplementation

Without

62.5

65.8

67.0

60.9

59.4

67.6

61.0

8.72

With

66.6

69.5

71.2

66.7

67.5

70.2

64.6

9.28

ąSEM

0.57

0.56

0.61

1.21

1.41

0.30

0.88

0.35

P-value

0.022

0.021

0.023

0.018

0.022

0.012

0.039

0.426

Interaction (roughage x enzyme)

BH

63.7c

66.4bc

66.9bc

63.6ab

57.8cd

67.7b

61.2bc

10.05a

BH-E

68.3a

70.8a

72.5a

71.6a

67.1ab

70.1a

65.4ab

10.89a

CS

63.3c

67.0b

68.6b

64.8ab

69.4ab

67.2b

64.1ab

9.01ab

CS-E

66.8ab

70.3a

72.4a

68.6ab

74.0a

70.2a

67.3a

9.51a

RS

60.6d

63.9c

65.5c

54.4c

50.9d

68.0b

57.8c

7.10b

RS-E

64.6bc

67.3b

68.8b

60.0bc

61.4bc

70.3a

61.1bc

7.45b

ąSEM

0.57

0.56

0.61

1.21

1.41

0.30

0.88

0.35

 

P-value

0.013

0.012

0.010

0.007

0.006

0.008

0.012

0.002

 

a, b, c, d Values in the same column for each item with different superscripts differ significantly at 5% level


BH rations showed the highest digestibility coefficients of DM and CF, while those containing CS had the highest digestibility coefficients of OM, CP and EE (P<0.05). Moreover, the digestibility coefficients of all nutrients increased significantly (P<0.05) with fibrozyme supplementation. The BH-E ration showed the highest digestibility coefficients of DM, OM, CP and CF, CS-E the highest EE digestibility and RS-E the highest NFE digestibility (P<0.05). These results agreed with those obtained by Bowman et al (2002) who found that cows receiving enzyme treated ration had a significantly higher DM, OM, NDF and ADF digestibility compared to cows receiving control ration. There was significant improvement in the diet digestibility of DM, OM, CP, NDF, ADF and total carbohydrates (TC) between the control and enzyme treated diets by goats (Prokasananda et al 2009).

 

Nutritive values

 

Nutritive values of the experimental rations are presented in Table 3. Ration based on CS showed the significantly (P<0.05) highest TDN value and those containing BH had the highest DCP value, while those having RS had the lowest TDN and DCP values. Moreover, the TDN value increased significantly (P<0.05) with fibrozyme supplementation. The CS-E ration recorded the highest TDN value and BH-E ration the highest DCP value (P<0.05). These results agreed with those obtained by Rode et al (1999) who found that total digestibility of nutrients was dramatically increased by enzyme treatment. Dean et al (2005) and Adesogan et al (2005) reported that enzyme improved the nutritive value of the diet.

 

Rumen liquor parameters

 

Ruminal liquor parameters during the different times are shown in Table 4.


Table 4.  Rumen fermentation activity of Friesian cows fed experimental rations

Item

pH value

TVFA's, meq/100 ml

NH3-N, mg/100 ml

Type of roughage

BH

7.04a

15.4b

15.1a

CS

6.79b

16.8a

13.9b

RS

7.10a

13.4c

12.1c

ąSEM

0.04

0.35

0.31

P-value

0.008

0.012

0.014

Enzyme supplementation

Without

7.04

14.4

14.4

With

6.91

16.0

13.0

ąSEM

0.03

0.35

0.31

P-value

0.033

0.024

0.022

Sampling time (hours)

0

7.09a

13.7b

12.6b

2

6.93ab

15.8ab

14.3ab

4

6.83b

16.7a

14.9a

6

7.04ab

14.6ab

13.0ab

ąSEM

0.04

0.35

0.31

P-value

0.062

0.031

0.056

Interaction (roughage x enzyme)

BH

7.09ab

14.6bc

16.0a

BH-E

6.99cd

16.2ab

14.3bc

CS

6.89d

15.8b

14.5b

CS-E

6.69e

17.7a

13.2cd

RS

7.15a

12.8d

12.7de

RS-E

7.04bc

14.0cd

11.6e

ąSEM

0.04

0.35

0.31

P-value

0.004

0.0010

0.009

a, b, c, d, e Values in the same column for each item with different superscripts differ significantly at 5% level.


Cows fed rations containing CS recorded the highest TVFA's and the lowest pH value, but those fed rations based on RS had the opposite trends (P<0.05). While, cows fed rations containing BH  showed the highest NH3-N concentration and those fed ration containing RS   had the lowest concentration (P<0.05). Moreover, ruminal pH value and NH3-N concentration decreased, while the concentration of TVFA's increased significantly (P<0.05) with fibrozyme supplementation.

 

The ruminal pH values were higher before feeding and decreased gradually until 4 hours after feeding then increased at 6 hours. However, the concentrations of TVFA's and NH3-N was lower before feeding and increased gradually until 4 hours after feeding then decreased at 6 hours. The CS-E had significantly (P<0.05) the lowest pH value and the highest TVFA's concentration and BH ration revealed the highest NH3-N concentration. These results are in accordance with those obtained by Adesogan et al (2005) who found that ruminal fluid pH tended to be lower in cows fed enzyme than in those fed the control diet, presumably due to easier enzymatic hydrolysis of the concentrate than the roughage into readily fermentable substrates that depress pH when fermented. Mean ruminal NH3-N concentration was lower significantly in cows fed enzyme treated diet than in cows fed the control diet. This suggests that there was enhanced uptake of NH3-N by the ruminal microbes probably due to greater fermentable metabolizable energy from this diet. Van Soest (1963) stated that the optimum pH value for growth of cellulytic microorganisms was 6.7 and the range for normal condition was about ą 0.5 pH degree. Russell and Dombrowski (1980) reported that ruminal total VFA production was closely related to ruminal pH, which can be considered an important regulator of microbial yield. Ruminal microorganisms utilize more NH3-N when more energy sources are fermented (Hungate 1966).

 

Milk yield

 

The effect of roughage type and fibrozyme supplementation on actual milk and 4% FCM yield are shown in Table 5.


Table 5.  Milk yield and composition of Friesian cows

Item

Milk yield, kg/day

Milk composition, %

actual

4% FCM

fat

protein

lactose

SNF

TS

Ash

Type of roughage

BH

16.6b

15.4b

3.51b

2.85a

4.24b

7.80a

11.3a

0.71

CS

18.1a

17.2a

3.66a

2.69b

4.39a

7.77a

11.4a

0.70

RS

14.3c

13.0c

3.39c

2.60c

4.08c

7.39b

10.8b

0.71

ąSEM

0.33

0.36

0.03

0.02

0.03

0.04

0.06

0.002

P-value

0.012

0.014

0.003

0.003

0.004

0.006

0.007

0.221

Enzyme supplementation

Without

15.7

14.4

3.46

2.68

4.22

7.61

11.1

0.71

With

17.0

15.9

3.58

2.74

4.25

7.69

11.3

0.70

ąSEM

0.33

0.36

0.03

0.02

0.03

0.04

0.06

0.002

P-value

0.051

0.038

0.010

0.174

0.571

0.339

0.104

0.129

Interaction (roughage x enzyme)

BH

16.0c

14.7c

3.44c

2.81a

4.22abc

7.74ab

11.2b

0.71a

BH-E

17.2b

16.1b

3.58b

2.89a

4.26ab

7.85a

11.4a

0.70ab

CS

17.4b

16.4b

3.59b

2.68b

4.37a

7.76ab

11.4ab

0.71a

CS-E

18.8a

18.0a

3.73a

2.69b

4.40a

7.78ab

11.5a

0.69b

RS

13.6e

12.3e

3.34d

2.55c

4.07c

7.33c

10.7c

0.71a

RS-E

14.9d

13.7d

3.44c

2.64bc

4.09bc

7.44bc

10.9c

0.71a

ąSEM

0.33

0.36

0.03

0.02

0.03

0.04

0.06

0.002

P-value

0.008

0.010

0.004

0.005

0.008

0.011

0.012

0.039

a, b, c, d Values in the same column for each item with different superscripts differ significantly at 5% level


Cows fed CS rations  recorded the highest actual milk and 4% FCM yield followed by those fed ration based BH , but those fed rations having RS  had the lowest yield (P<0.05). The yield of actual milk and 4% FCM increased significantly (P<0.05) with fibrozyme supplementation by 8.28 and 10.42%, respectively. Cows fed CS-E ration recorded significantly (P<0.05) the highest actual milk and 4% FCM yield. The increase associated with feeding ration containing CS is attributed to the increase dietary non-fiber carbohydrates concentration particularly starch (Table 1), which increased the ruminal total VFA production (Table 4). These results agreed with those obtained by Schingoethe et al (1999) who reported that enzyme induced increase in milk production occurred during the first 100 day postpartum dairy cows. Adesogan et al (2005) found that enzyme application increased milk yield in dairy cows. Prokasananda et al (2009) showed 180 to 260 ml/day of higher FCM for goats fed enzyme treated diet compared with control diet.

 

Milk composition

 

The percentages of all milk constituents as affected by roughage type and enzyme supplementation are presented in Table 5. Cows fed rations containing CS  recorded the highest percentages of fat, lactose and TS in milk and those fed BH rations  showed the highest percentages of protein and SNF, however those fed rations having  RS  had the lowest protein percentage (P<0.05). Only fat percentage increased significantly (P<0.05), but the other constituents were insignificantly increased (P>0.05) with fibrozyme supplementation. Cows fed CS-E ration showed the highest fat, lactose and TS percentages, while those fed BH-E had the highest protein and SNF percentages (P<0.05). These results are in accordance with those obtained by Saleh (2007), Zeid et al (2008) and Khattab et al (2009) they found fibrozyme supplementation led to significant increase in the percentages of milk constituents in cows and buffaloes.

 

Feed conversion

 

Feed conversion by lactating Friesian cows as shown in Table 6 revealed that cows fed rations with RS  recorded the highest amounts of DM and TDN per 1 kg FCM followed by those fed rations containing BH , while those fed rations having CS  had the lowest amounts (P<0.05).


Table 6.  Feed conversion and economic efficiency of Friesian cows

Item

Feed conversion

Economic efficiency

DM, kg/kg FCM

TDN, k g/kg FCM

DCP, g/kg FCM

ADFC (LE)

FC (LE),  /kg FCM

I FCM (LE)

EE

Type of roughage

BH

1.06b

0.67b

110.4a

22.9a

1.49a

30.8b

1.34c

CS

0.97c

0.64c

90.1b

20.6b

1.20c

34.4a

1.67a

RS

1.17a

0.69a

85.1c

16.7c

1.29b

26.0c

1.56b

ąSEM

0.02

0.01

2.07

0.49

0.02

0.73

0.03

P-value

0.004

0.002

0.014

0.009

0.002

0.012

0.003

Enzyme supplementation

Without

1.11

0.68

96.2

19.8

1.38

28.9

1.46

With

1.02

0.66

94.2

20.3

1.27

31.9

1.58

ąSEM

0.02

0.01

2.07

0.49

0.02

0.73

0.03

P-value

0.007

0.077

0.634

0.666

0.037

0.038

0.030

Interaction (roughage x enzyme)

BH

1.10b

0.67b

110.1a

22.6a

1.54a

29.4c

1.30e

BH-E

1.02c

0.66bc

110.6a

23.1a

1.44b

32.2b

1.39d

CS

1.02c

0.65c

91.5b

20.4b

1.25d

32.7b

1.60b

CS-E

0.93d

0.63d

88.8c

20.8b

1.15e

36.0a

1.73a

RS

1.22a

0.71a

87.0c

16.5c

1.34c

24.6e

1.49c

RS-E

1.12b

0.68b

83.1d

16.9c

1.23d

27.4d

1.62b

ąSEM

0.02

0.01

2.07

0.49

0.02

0.73

0.03

P-value

0.003

0.002

0.009

0.007

0.002

0.010

0.002

a, b, c, d Values in the same column for each item with different superscripts differ significantly at 5% level.

ADCF = average daily feed cost, FC (LE)/ kg FCM = feed cost (Egyptian pound LE)/ kg fat corrected milk, IFCM = income of fat corrected milk, EE = economic efficiency


However, cows fed ration contained BH  recorded the higher amount of DCP per 1 kg FCM followed by those fed ration contained CS , while those fed ration contained RS  had the lowest amount. Fibrozyme supplementation led to significant (P<0.05) decrease in the amount of DM per kg FCM. Cows fed CS-E recorded the lowest requirements of DM and TDN per kg FCM, while those fed RS-E showed the lowest DCP/ kg FCM (P<0.05). These results agreed with those obtained by Saleh (2007) who indicated that the amounts of DM, TDN and DCP required per kg FCM decreased with fibrozyme supplementation. Adesogan et al (2005) found that enzyme supplementation increased feed efficiency. Prokasananda et al (2009) reported that feed intake g/kg FCM yield in goats was also 7% less in enzyme treated diet compared with control diet.

 

Economic efficiency

 

Results in Table 6 showed that cows fed rations contained BH showed the highest average daily feed cost (ADFC) followed by those fed rations contained CS, while those fed rations contained RS had the lowest cost (P<0.05). However, average daily feed cost did not significantly (P<0.05) affected by fibrozyme supplementation. Feed cost / kg FCM (FC/FCM) was significantly higher (P<0.05) for cows fed BH rations compared with those fed CS rations and RS rations and it decreased significantly (P<0.05) with fibrozyme supplementation. Cows fed CS rations recorded the highest income of FCM yield (IFCM) and economic efficiency (EE) as the ratio between income of FCM yield and daily feed cost followed by those fed BH rations, while those fed RS rations had the lowest output and their increased significantly (P<0.05) with enzyme supplementation. Cows fed RS ration revealed the lowest average daily feed cost, wile those fed CS-E recorded the lowest feed cost/ kg FCM and the highest income of FCM and economic efficiency. These results agreed with those obtained by Saleh (2007) who found that feed cost as LE/ kg FCM decreased and economic return increased with fibrozyme supplementation for dairy cows. Zeid et al (2008) reported that average daily feed cost, output of milk yield and economic efficiency increased with fibrozyme supplementation for dairy cows.

 

Conclusion   


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Received 5 May 2010; Accepted 16 May 2010; Published 10 June 2010

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