Ensiled and dried peanut haulm as replacement of concentrate for crossbred heifers fed poor quality forages

Bui Xuan An

University of Agriculture and Forestry, HoChiMinh City, Vietnam

Summary

Twenty four crossbred heifers, given forages of low nutritive value, were divided equally into 3 groups with different supplements: CONC., 1 kg/d concentrate; SILAGE, 2 kg DM/d ensiled peanut haulm; DRY, 2 kg DM/d dry peanut haulm. The experiment period was 120 days. DM intakes were 5.12, 5.82, and 5.79 kg/d, and live weight gains were: 107, 195, 230 g/d, for treatments CONC., SILAGE and DRY, respectively.

Keywords: Peanut haulm, ensile, dry, cattle, growth.

Introduction

In Viet Nam, the basal diet of most of the cattle and buffaloes is based on crop residues, roadside grass or grazing on boundaries between crops. These diets are imbalanced in nutritional value and variable according to seasons. In order to develop a sustainable ruminant production system in Vietnam, efforts are directed to making the best use of local feed resources by adjusting the production system according to the local conditions. The use of appropriate supplements is a fundamental component of the feeding strategy in order to balance nutrients at the level of the rumen and of the animal (Leng and Preston 1983, Preston and Leng 1987).

More than 260,000 ha of Peanut were grown in Vietnam (General Statistical Office 1997) and it produced more than 1.5 million tons of fresh peanut haulm (Le Viet Ly and Bui Van Chinh 1996). The peanut haulm is a promising byproduct for animal feed (Duong Thanh Lien et al 1998, Bui Van Chinh et al 1996) but little research has been carried on the use of the haulm as animal feed in Vietnam and it is not well used by farmers in the country (Bui Xuan An 1998).

The aim of this study was to determine the effect on performance of growing crossbred cattle of using ensiled and dry peanut haulm as replacement for concentrate with a basal diet derived, according to availability, from native grasses, sugarcane tops and rice straw given ad libitum.

Materials and methods

Twenty four crossbred Holstein-Sindhi heifers (180 kg liveweight, 20 months of age in average) were divided into three homogeneous groups according to liveweight and fed the same basal diet (native grasses given in restricted amounts; sugarcane tops and rice straw given ad libitum, according to availability). The experimental period was 120 days in the dry season. The treatments were based on equal supplement price:

• CONC: 1 kg/d concentrate mixture
• SILAGE: 2 kg DM/d ensiled peanut haulm;
• DRY: 2 kg DM/d dry peanut haulm

Table 1: Experimental design for heifers fed poor quality forages and supplemented with concentrate, ensiled or dried peanut haulm.
Period	Days	CONC	SILAGE	DRY
Pre-experiment	1 to 7	CONC	CONC	CONC
Adaptation	8 to 29	CONC	SILAGE	DRY
Experiment	17 to 120	CONC	SILAGE	DRY
Animal number	-	8	8	8
Liveweight	-	179.5±16	180.0±17	180.0±13
Age	-	20.5±1.7	20.7±1.7	20.5±1.1

After seed collection, one half of the peanut haulm was sun-dried and the other half was chopped into 5-cm pieces and ensiled with 5% of final molasses in a bunker silo. The concentrate was made of 81% rice bran, 14.3% peanut cake meal and 4.7% mineral mixture. The measurements were: dry matter (by a forced drought oven), nitrogen content (Macro-Kjeldahl), Neutral detergent fiber NDF (refluxing) following methods of AOAC 1980. Feed samples were collected each 14-day time. The data for feeds are shown in Table 2. Feed intake was measured every day. The cattle were weighed every 14 days and records kept of feed intake.

In an on station trial, three fistulated cows fed rice straw at libitum, and 4kg of green native grasses, were arranged in a Latin Square design with 3 fourteen-day periods in order to measure the in sacco DM degradabilities (Orskov et al 1980) of samples of rice straw, sugarcane top, native grasses, concentrate, ensiled and dried peanut haulm (used in the experiment).

Data were analysed using the Analysis of Variance in the General Linear Model of Minitab software package (Minitab 1993).

Results and discussion

The basal diet was characterized by a low nitrogen content, a high fiber content and a low digestibility. In dry season, the available feeds for cattle were poor crop by-products and mature grasses with high lignified level. This is common constraint for cattle production in the tropics. The peanut haulm has as high nitrogen content as good leguminous green forages (Duong Thanh Lien et al 1985, Bui Van Chinh et al 1996, Bui Xuan An 1998) and is an interesting animal feed resource in dry periods. The diet supplemented with peanut haulm had higher nitrogen content than the diet with concentrate.

There was an indication that intake of the basal feed (the low- nutritive value component of the diet) was the same but the total diet was higher when peanut haulm was given. The liveweight gains of the animals supplemented with ensiled or dried peanut haulm were higher than the liveweight gains of the animals supplemented with concentrate. This result was similar to data observed in some tropical places experimenting on supplement of leguminous forages (Speedy and Pugliese 1992, Bui Xuan An and Ngo Van Man 1992, Dinh Van Binh et al 1994).

Table 2: Chemical composition of feeds for experimental heifers
Feed	n	DM		% in DM
			N x 6.25	NDF	Digestibility
Rice straw	7	57.2±1.2	4.2±0.4	69.5±4.0	40.1±3.1
Sugar cane top	7	42.7±1.3	3.4±0.4	68.1±5.5	35.7±3.2
Native grass	7	37.0±2.2	9.2±1.2	70.2±6.3	44.5±5.0
Ensiled peanut haulm	8	33.1±1.4	14.4±0.3	52.0±4.7	49.5±6.5
Dried peanut haulm	8	89.3±1.2	14.2±0.2	51.3±3.3	47.1±5.7
Concentrate	8	86.5±0.9	16.0±0.1	30.2±2.5	66.7±6.3

In a simple economic analysis considering the labour and cost for supplementing, the supplementation of 2 kg dry matter of dried or ensiled peanut haulm had the same cost but liveweight gain was increased by 77 and 85% respectively. Drying the haulm spent more labour but when feeding to animals less and easier work was needed with dried haulm than with ensiled haulm.

Table 3: Feed dry matter intake and Liveweight change of crossbred heifers fed poor quality forages and supplemented with concentrate, ensiled or dried peanut haulm.
	CONC	SILAGE	DRY	P
Feed DM intake, kg/d
Basal feed	4.20±0.15	4.11±0.17	4.20±0.31	>.05
Total diet	5.12±0.21 (a)	5.82±0.16 (b)	5.79±0.22 (b)	<.001
Liveweight change
Initial LW, kg	179.5±15	180.0±19	180.0±16	>.05
Final LW, kg	189.2±14	198.0±18	197.3±15	>.05
Gain, g/day*	108±18 (m)	192±24 (n)	201±67 (n)	<.001

*Adjusted by covariance for initial weight.
a, b or m, n different with P<.05

Conclusion

As supplement to poor roughage diet for growing heifers, the replacement of the concentrate by either ensiled or dry peanut haulm had positive effect on liveweight gains. This strongly indicates that (i) there was a deficiency of rumen nitrogen content when the basal diet was composed of grasses, cane tops and rice straw; (ii) the unsuitability of the concentrate supplement for supplying ammonia for rumen microorganisms, and (iii) peanut haulm is an interesting source of ruminant feed specially in dry season when the basal diet is poor.

References

Go to top