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 9^o 03’28.82” E latitude and 38^o30’17.59” 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, Y_ij is the observation on i^th treatment in j^th block; μ is overall mean; T_i (i=1, 2, 3) is the effect of i^th treatment; B_i(i=1, 2, 3) is the effect of i^th block; E_ij = 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	0.72^a	0.67^b	0.56^c	0.15	0.01
NDF	2.52^b	2.66^a	2.25^c	0.06	0.02
ADF	1.48^b	1.59^a	1.35^c	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	75.37^a	68.32^b	60.11^c	0.57	0.000
Organic matter	73.58^a	66.96^b	57.54^c	0.76	0.000
Crude protein	78.05^a	70.04^b	61.97^c	1.04	0.000
Neutral detergent fiber	77.72^a	72.15^b	61.05^c	0.40	0.000
Acid detergent fiber	62.55^a	57.05^b	44.06^c	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	150.2^a	145.3^ab	132.2^b	4.51	0.01
Daily gain, kg	0.58^a	0.52^ab	0.38^b	0.03	0.000
DM intake, kg/d	4.72	4.58	3.96	0.19	0.09
CP intake, kg/d	0.72^a	0.67^ab	0.56^b	0.15	0.01
Feed conversion#	6.56^c	8.81^b	10.42^a	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

AOAC 1990 Official Methods of Analysis, 18^thedn. Association of Official Analytical Chemists, Vrginia, USA.

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.

Phipps R H, J D Sutton, D E Beever and A K Jones 2000 The effect of crop maturity on thenutritional value of maize silage for lactating dairy cows. Food intake and milk production. Anim.Sci,71, 401-409.

Preston T and Leng R 1987 Matching Ruminant Production Systems with Available Resources in the Tropics and Sub-Tropics. http://www.cipav.org.co/PandL/Preston_Leng.htm

SAS (Statistical Analysis System) 2002 SAS Institute Inc, NC, USA.

Thorne P J, Thornton P K, Kruska R, Reynolds L, Waddington, S R Rutherford A and Othero A N 2002 Maize as food, feed and fertilizer in intensifying crop- livestock systems in East and southern Africa: An ex ante impact assessment of technology interventions to improve smallholder welfare. ILRI Impact Assessment Series 11. International Livestock Research Institute, Nairobi, Kenya, 123 p.

Tilley J M A and Terry R A 1963 A two stage method for the in vitro digestion of forage crops. Journal Britannia Grassland Society.18: 104-111

Van Soest P J and Robertson J B 1985 Analysis of Forages and Fibrous Foods a Laboratory Manual for Animal Science. Cornell University, Ithaca, NY.

Zom R L G, Bannink A, Goselink R M A 2012 Effect of increased maturity of silage maize at harvest on conservation, dairy cow performance and methane emission. Wageningen UR Livestock Research, Wageningen, The Nederland’s