Use of Cassava as Animal Feed

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Effect of cassava hay and high-quality feed block supplementation on milk production in dairy cows

 S Koakhunthod, M Wanapat, C Wachirapakorn, N Nontaso*,
P Rawlinson** and N Sornsungnern

Department of Animal Science. Faculty of Agriculture. Khon Kaen University, Thailand.
* Department of Microbiology, Faculty of Science, Khon Kaen University, Thailand.
** Department of Agriculture, University of Newcastle upon Tyne, UK.

Abstract

This experiment was conducted to investigate the effect of cassava hay (CH) incorporated in a high-quality feed block (HQFB) on feed intake, digestibility, rumen fermentation, milk production and milk composition in lactating dairy cows. Six Holstein-Friesian crossbred cows in mid-late lactation were randomly allocated in a switchback design. There were three treatments: control (no supplementation of HQFB); HQFB (supplementation of HQFB without CH); and HQFB-CH (supplementation of HQFB with CH). The cows were offered a commercial concentrate with a ratio to milk yield of 1:2. Urea-treated rice straw was given ad libitum as a roughage source. 

Total dry matter intake and digestion coefficient of dry matter in the HQFB-CH treatment were higher than in the other groups. The concentration of NH3-N, the pH and the microbial populations in the rumen did not differ between treatments. Milk yield in the two HQFB treatments were higher than in the non-supplemented treatment. Fat-corrected milk (3.5% FCM), percent milk fat and total solids in the HQFB-CH  treatment were higher than for the other treatments.   

It was concluded that supplementation with a high quality feed block containing cassava hay improved feed intake, digestibility, milk yield and milk composition.

Key words:  Cassava hay,  high-quality feed block,  dairy cows,  milk yield,  milk composition


Introduction

During the dry season in the tropics the basal diets of ruminants are native grasses or crop-residues. These diets are low in crude protein, imbalanced in essential minerals, and of low dry matter digestibility, and support low feed intake by ruminants (Wanapat 1995). Methods of increasing the utilization of low quality roughages include physical treatments (eg: chopping and grinding), chemical treatments (eg: sodium hydroxide, anhydrous ammonia, urea-ensiling) and biological treatments (eg: white rot fungi). However, of these techniques, chemical treatment by a 5% urea solution has proved to be the most simple, cost-effective and practically sound method for small-holder farmers in the tropics (Wanapat 1999).

 The supplementation of deficient nutrients in the form of fermentable nitrogen, easily degradable carbohydrate and minerals can improve roughage intake (Garg and Gupta 1992). The high-quality feed block (HQFB) contains urea, molasses, by-pass protein and other essential ingredients and has been used as a  supplement for ruminants. Supplementation with HQFB (Wanapat et al 1999) or a urea-molasses block (Srinivas et al 1997) has resulted in improvements in terms of intake of rice straw, digestibility, growth, and milk yield and composition.

Cassava or tapioca (Manihot esculenta, Crantz) has been shown to be a promising dry season feed especially the aerial part when sun-dried as cassava hay (CH), which has a high digestibility of dry matter and protein and apparently contains a  high proportion of rumen by-pass protein because of the presence of tannin-protein complexes. Supplementation with 1 kg/hd/d of CH made it possible to reduce the concentrate: milk ratio from 1:2 to 1:3  and to improve the milk composition (Wanapat et al 2000).

The objective of this experiment was to investigate the effect of incorporating cassava hay  (CH) in a HQFB supplement on feed intake, digestibility, rumen ecology, and milk production and composition in lactating dairy cows.

 Materials and Methods

Six Holstein-Friesian crossbreds in mid-late lactation were randomly paired and assigned to receive the respective dietary treatments according to a Switchback design. The dietary treatments were:

The animals were kept in individual pens and allowed two weeks to adjust to their respective feeds before the treatments were imposed, which was for a period of 21 days on each treatment. A  concentrate supplement was given to all cows in two equal amounts during the morning and afternoon milking, at a ratio of 1:2 (concentrate: milk yield). Urea-treated (5%) rice straw was offered to all animals on ad libitum basis. High-quality feed blocks (HQFB) were prepared to contain fermentable nitrogen and an easily degradable carbohydrate source (Table1). The solid ingredients were mixed first and then with molasses in a 100 kg batch using a rotating cement mixer. The mixed ingredients were then pressed into blocks of about 10 kg in a hydraulic press. The HQFB were available at all times, according to the respective treatments and were weighed once a week. 

Milk yields from all animals were recorded daily and samples of milk were taken from afternoon and morning milk for analysis of fat, protein, lactose, solids-not-fat and total solids by Milko-Scan during the last day of each period. Samples of feed were  taken for dry matter (DM), ash, crude protein (CP), neutral-detergent-fiber (NDF), and acid-detergent-fiber (ADF) analyses (Table 2). Feces were taken from the rectum of each animal for the last three days of each period and analyzed for chemical composition using standard procedures. Rumen fluid was collected through a stomach tube with a vacuum pump at 4 hours post feeding on the last day of each period and pH, NH3-N and microbial population measured. Each animal was weighed at the beginning and at the end of each period. All data were subjected to analysis of variance using the GLM procedure, and treatment means were compared using Duncan’s New Multiple Range Test (SAS 1985). 

Table 1. Ingredients in the high-quality feed block (HQFB) (% by weight)

 

HQFB

HQFB-CH

Molasses

40

42

Cassava hay

0

30

Rice bran

30

0

Urea

13

11

Sulphur

1

1

Minerals

1

1

Salt

1

1

Tallow

2

2

Cement

12

12

  

Results and Discussion 

Table 2. Chemical composition of urea-treated rice straw (UTRS), concentrate and feed block with (HQFB-CH) or without (HQFB) cassava hay (CH) (as % of dry matter)

 

Dry matter

Organic matter

Crude protein

NDF

ADF

UTRS

55.2

83.6

6.8

83.0

58.1

Concentrate

85.0

92.2

13.6

24.3

10.7

HQFB

79.8

76.4

36.0

26.2

20.2

HQFB-CH

80.2

76.1

33.2

23.2

17.2

 Intake of urea-treated rice straw by animals in the HQFB-CH treatment tended to be higher than in the HQFB and control treatments (Table3). Total dry matter intake in the HQFB-CH treatment was higher than in the control (p<0.05). Dry matter digestibility in the HQFB-CH treatment was higher than in the control treatment (p<0.05).
   

Table 3. Effect of cassava hay in a high-quality feed block on feed intake and dry matter digestibility in lactating dairy cows fed a basal diet of urea-treated rice straw

                               

Dietary treatments

 

Item

Control

HQFB-CH

HQFB

SEM

UTRS DM intake

 

 

 

     kg/day                              

5.44          

6.20

5.61

0.17

     % of BW                          

1.44

1.57

1.55

0.03

HQFB  DM intake               

     kg/day                              

 

0.79

0.65        

0.03

     % of BW                          

 

0.20

0.18

0.01

Total DM intake

     kg/day                              

9.18a

11.1b

10.1ab     

0.31

     % of BW                          

2.43

2.78

2.82

0.07

DM digestibility, %            

48.4a

53.4b

51.1ab

0.76

Control: concentrate to milk yield at 1:2 
HQFB: concentrate to milk yield at 1:2 + HQFB (without cassava hay)
HQFB-CH: concentrate to milk yield at 1:2 + HQFB-CH (with cassava hay)
UTRS: Urea-treated rice straw; 
 SEM=standard error of  means; ab Values in the same row with different superscripts differ (p<0.05).

The rumen pH and NH3-N concentration were similar among treatments (Table 4). Total bacterial direct count, total viable bacterial count, cellulolytic bacteria, proteolytic bacteria and fungal zoospores in rumen fluid tended to be higher in the HQFB-CH treatment than in the HQFB and control (Table 4).

Table 4. Effect of cassava hay in the feed block on pH, NH3-N and microbial populations in the rumen of lactating dairy cows fed urea-treated rice straw

 

Dietary treatment

 

                               

Control

HQFB   

HQFB-CH

SEM

pH          

6.64

6.50

6.59

0.07

NH3-N (mg %)     

7.95

8.61

9.14

0.71

Bacteria (×10-9 cells/ml)      

6.56

6.74

7.25

3.05

Protozoa (×10-5 cells/ml)     

6.30

6.20

6.10

0.34

Holotrichs (×10-5 cells/ml)  

2.30

2.30

2.40        

0.52

Entodiniomorphs (×10-5 cells/ml)

4.00

3.90

3.70

0.83

Fungal zoospores (×10-7 cells/ml)

3.02

3.75

4.16

3.87

Total viable count (×10-10 CFU/ml)          

2.51

2.86        

3.16

0.23

Cellulolytic bacteria (×10-9 CFU/ml)

3.04

3.21

3.48

0.27

Amylolytic bacteria (×10-8 CFU/ml)

1.60

2.22

2.19

0.15

Proteolytic bacteria (×10-8 CFU/ml)

1.71

2.02

2.13

0.19

SEM=standard error of the means 

 Yields of milk, fat-corrected milk (3.5% FCM), fat and protein, and percent fat  and total solids were higher for the HQFB-CH treatment than for the HQFB and control treatments (Table 5). 

Table 5. Effect of cassava hay (CH) in the feed block (HQFB) on milk yield and milk composition in lactating dairy cows fed urea-treated rice straw

                                                                            

Dietary treatment

 

                               

Control

HQFB

HQFB-CH

SEM

Yield, kg/day

Milk       

7.58a       

8.85b

9.36b

0.44

3.5% FCM            

7.66a       

8.43b

9.94c

0.46

Fat                         

0.27a       

0.29a       

0.37b

0.02

Protein                  

0.23a

0.25a       

0.31b       

0.02

Milk composition, %

 

Fat                         

3.39a

3.53ab

4.08b       

0.16

Protein                  

2.87

2.96

3.32

0.11

Lactose                 

5.01

4.85

5.00

0.04

SNF                       

7.98

8.01

8.01

0.42

Total solids          

12.1a

12.0a

13.1b

0.25

SEM=standard error of the means; SNF=solid-not-fat
ab Values in the same row with different superscripts differ (p<0.05)


Conclusions

It can be concluded from this experiment that incorporating cassava hay in a high quality feed block:

·         Increased intake of urea-treated rice straw and total feed dry matter 
·         Increased dry matter digestibility
·         Improved rumen ecology

References

Garg  M R  and Gupta B N  1992  Effect of supplementing urea molasses mineral block lick to straw based diet on DM intake and nutrients utilization. Asian Australian Journal Animal Science. 5 (1):39-44. 

SAS  1985  SAS User’s Guide : Statistics, Version 5. SAS Inst, Cary NC

 Srinivas  B, Gupta B N and Srinivas B 1997 Urea-molasses-mineral block lick supplementation of milk production in crossbred cows. Asian Australian Journal Animal Science 10 (1): 47-53.

Wanapat  M  1995  Nutritional strategies based on crop-residues to increase swamp buffalo production and draft efficiency on farms. In : Proceedings International Workshop on Draft Animal Power to Increase Farming Efficiency and Sustainability (Editor: M  Wanapat), Funny Press Publishing. Ltd., Bangkok, Thailand. 

Wanapat  M  1999  Feeding Ruminants in the Tropics Based on Local Feed Resources. Khon Kaen Publishing Company Ltd, Khon Kaen, Thailand, 236 pp.

Wanapat  M, Petlum A and  Pimpa O 1999  Strategic supplementation with a high quality feed block on roughage intake, milk yield and composition and economic return in lactating dairy cows. Asian Australian Journal Animal Science. 12(6): 901-903. 

Wanapat  M,  Petlum A and Pimpa O 2000  Supplementation of cassava hay to replace concentrate use in lactating Holstein-Friesian crossbreds. Asian Australian Journal Animal Science. 13(5): 600-604.

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