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Citation of this paper

Effect of maize stover silage in total mixed rations on growth of dairy heifers

Geberemariyam Terefe, Getu Kitaw, Mulugeta Walelegne, Dereje Fekadu, Mesfin Dejene, Aemiro Kehaliw and Bethlehem Mekonnen

Ethiopian Institute of Agricultural Research (EIAR), Holeta Agricultural Research Center, P O Box 31, Holeta, Ethiopia
geberemom@gmail.com

Abstract

Dual purpose (Food-Feed) maize was planted and harvested at dough stage. After harvesting cobs was removed and used for human consumption. The residual partially dry green maize stover (35% DM) was subjected to chopping (3-5 cm in length) and ensiled in the presence of molasses additive added at the rate of 3% on a DM basis. During the dry season, ensiled maize stover (EMS) was kept for 45 days. A total of twelve high- grade (Boran X Friesian) post weaned diary heifers (109.41 10.70 kg LW) were randomly assigned to one of the three dietary treatments (MS50 = 50% EMS: 50%concntrate (CM); MS60 = 60% EMS: 40% CM) and MS70 = (70% EMS: 30% CM) in a completely randomized block design. The diets were fed as totally mixed rations (TMR) offered ad-libitum allowing 15-20 % refusal. The experiment consisted of 90 days of feeding trial and 7 days of digestibility trial

There was no difference in dry matter and organic matter intake among treatments. Crude protein intake was higher in MS50. The lowest NDF and ADF intakes were observed in MS70. The higher DM, CP, NDF and ADF apparent digestibility were observed in MS50. Higher daily body weight gain was recorded in the heifers fed MS50.

Keywords: bodyweight gain, total mixed ration


Introduction

In Ethiopia, maize is planted on a vast area of land (more than 2.4 million ha) according to recent, data from CSA (2018/19). The crop is the food staple for several million families, the majority of whom also rear dairy cattle (Thorne et al 2002). Nutritionally, it is well-documented that an increased maturity at harvest results in an increased grain filling for human consumption, starch-to- Neutral Detergent Fiber (NDF) ratio and increased fraction of rumen by-pass starch in maize silages (Phipps et al 2000). Inclusion of maize silage which is harvested at a more mature stage (>350 g DM/kg fresh weight, dough stage) in the diet of dairy cows could be an option to increase the supply of starch and rumen by-pass starch. Moreover, a related study indicated that maize silage harvesting at the dough stage of the grain results in higher yields of dry matter, starch and energy (Zom et al 2012). Therefore, increasing maturity may also contribute to an increased self-sufficiency rate for feed and hence reduce the farm purchases of feeds.

Therefore, the objectives of this study were to evaluate the effect of dual-purpose maize stover silage based total mixed ration on feed intake, digestibility and growth performances of post weaned diary heifers.


Materials and methods

Description of the study area

The study was carried out at Holeta Agricultural Research Centre, Ethiopia. The centre is located at 9o 03’28.82” E latitude and 38o 30’17.59” E longitude at an elevation of 2,400 m above sea level. The mean annual temperature and rainfall during the study were 18 oC and 1225 mm, respectively.

Experimental design

A total of twelve weaned diary heifers (109 10.70 kg) were randomly assigned in a completely randomized block design. They were drenched with broad-spectrum anti-helminthic (Albendazole 2500 mg) prior to the commencement of the feeding trial. The heifers were kept in individual pens.

Dual-purpose maize (food-feed) was harvested at dough stage) after the cobs have been already removed for human consumption. The partially dried, green maize stover (35% DM) was chopped (3-5 cm in length) and ensiled for 45 days in above-ground silo with 3% (as DM) of molasses.

Table 1. Feed ingredients in the total mixed rations (TMR) (DM basis)

MS50

MS60

MS70

Ensiled maize stover (EMS)

50

60

70

Wheat bran

10

8.2

6

Cotton seed cake

6.5

5.2

3.9

Noug seed cake

18

14.4

10.8

Molasses

15

12

9

Salt

0.5

0.2

0.3

Concentrate

50

40

30

CP, %

15.1

14.8

14.2

The feeding trial was for 90 days. The TMR were offered ad-libitum allowing 15-20 % of refusal.

Digestibility trial

At the end of the experiment, faeces from each calf were collected, measured, and recorded for the consecutive seven days. Faecal and feed samples were taken for analysis by methods of AOAC (1990). NDF ADF and lignin (Van Soest and Robertson 1985), in vitro organic matter digestibility (Tilley and Terry 1963) was determined.

Statistical analysis

The data were analysed by ANOVA (SAS, 2002). The model was:

Where, Yij is the observation on ith treatment in jth block; μ is overall mean; Ti (i=1, 2, 3) is the effect of ith treatment; Bi (i=1, 2, 3) is the effect of ith block; Eij = Random error (residuals)


Results

Table 2. Composition of feed ingredients and TMR (g/kg DM)

DM

Ash

CP

NDF

ADF

Lignin

DOMD

ME (MJ/
KgDM)

Ensiled maize stover

390.42

67.80

62.00

621.20

382.10

90.70

602.70

9.64

Wheat bran

900.02

62.10

166.20

472.1

190.5

44.20

704.20

11.27

Cotton seed cake

910.22

62.60

290.50

442.4

244.2

54.20

630.10

10.08

Noug seed cake

910.42

78.70

332.10

424.4

296.9

78.70

628.70

10.09

Feed Intake

There was no difference in DM intake among diets (Table 3) CP intake in MS50 was higher compared to the other treatments.

Table 3. Feed intakes (kg/d)

MS50

MS60

MS70

SEM

p

Dry matter

4.72

4.58

3.96

0.19

0.09

Organic matter

4.26

4.39

3.43

0.08

0.01

Crude protein

0.72a

0.67b

0.56c

0.15

0.01

NDF

2.52b

2.66a

2.25c

0.06

0.02

ADF

1.48b

1.59a

1.35c

0.03

0.05

‘Baypass’ protein, g/d

78.66

62.93

47.20

Mean values without common superscripts are different at p <0.05

Apparent digestibility

Digestibility coefficients of all proximate constituents were decreased y when green maize stover silage replaced a preplaced a protein rich concentrate in the diet of growing dairy heifers (Table 4).

Table 4. Apparent digestibility (%)

MS50

MS60

MS70

SEM

p

Dry matter

75.37a

68.32b

60.11c

0.57

0.000

Organic matter

73.58a

66.96b

57.54c

0.76

0.000

Crude protein

78.05a

70.04b

61.97c

1.04

0.000

Neutral detergent fiber

77.72a

72.15b

61.05c

0.40

0.000

Acid detergent fiber

62.55a

57.05b

44.06c

0.35

0.000

Mean values without common superscripts are different at p <0.05

Growth and feed conversion

Growth and feed conversion pf the dairy heifers were depressed with linear trends as ensiled green maize stover replaced protein-rich concentrate in the diet (Table 5). However, a better way to understand the results is by plotting the growth rates as a function of the protein derived from the two oil seem by products (Figures 1 and 2). The protein derived from the two oil seed s (Noug and cotton) can be expected to be of low solubility (due to the heat generated in oil extraction) which will facilitate its escaped from the rumen for more efficient enzymic digestion in the intestine, resulting in better live weight gain and feed conversions (Preston and Leng 1987).

Table 5. Growth performance of dairy heifers fed increasing levels of green maize stover silage replacing concentrates

MS50

MS60

MS70

SEM

p

Initial LW, kg

98

98.5

98

0.125

0.08

Final LW, kg

150.2a

145.3ab

132.2b

4.51

0.01

Daily gain, kg

0.58a

0.52ab

0.38b

0.03

0.000

DM intake, kg/d

4.72

4.58

3.96

0.19

0.09

CP intake, kg/d

0.72a

0.67ab

0.56b

0.15

0.01

Feed conversion#

6.56c

8.81b

10.42a

0.09

0.0001

#DM intake/ LW gain Mean values without common superscripts are different at p <0.05



Figure 1. Relationship between growth rate and intake of
protein derived from nought cake and cottonseed meal
Figure 2. Relationship between feed conversion and intake of
protein derived from nought cake and cottonseed meal


Discussion

The better growth and feed conversion on the MS30 diet reflected the effect of the super balance of nutrients in the concentrate mixture and specifically the greater intake of bypass protein provided by the noug cake in cotton seed meal in the coventrate.


Conclusions

Growth and feed conversion pf dairy heifers were depressed with linear trends as ensiled green maise stover the greater intake of bypass protein provided by the noug cake in cotton seed meal in the coventr maize stover replaced a conventional protein-rich concentrate in the diet. It is proposed that rich in Noug cake ment of concentrate with maize stover silage increased from 50 to 70 %. Raising. heifers by using 50 % dual-purpose maize stover silage and 50 % concentrate based total mixed ration can be recommended for wider use at field levels.


Acknowledgment

The authors would like to thank the Ethiopian Institute of Agricultural Research.


References

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CSA (Central Statistical Agency) 2018/19 The federal democratic republic of Ethiopia central statistical agency agricultural sample survey 2018/19 (2011 E.C.). Volume I. Report on area and production of major crops. Statistical bullet in 589. Addis Ababa, Ethiopia.

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