Effect of an oil drench on the growth rate of cattle fattened on grass, supplemented with molasses, rice bran or rice straw
 

Nguyen Thi Hong Nhan, Nguyen Trong Ngu, Vo Van Son , T R Preston*and R A Leng**

Cantho University, Cantho, Vietnam
nthnhan@ctu.edu.vn
* regpreston@utafoundation.org
** rleng@ozemail.com.au

Abstract

The hypothesis to be tested was that the growth response of crossbred cattle to defaunation with a drench of soya bean oil would be greater when the diet was based on molasses compared with rice straw. Studies was made on the effects of defaunation when cattle received different sources of carbohydrate at low and high levels of rumen ammonia . The design was a 3*2 factorial arrangement of three basal diets (molasses, rice bran and rice straw) and with or without an oil drench (0 or 6 ml soya bean oil /kg live weight). Individual treatments were: RF: rice straw without urea plus restricted grass (45+45% DM basis) and rice bran (10 % DM basis). RFO: Same as RF with drench of soya bean oil at the rate of 6ml/kg live weight at the start of the trial. RFU: rice straw plus restricted grass (50 and 50% DM basis)+50 urea/100 kg LWt. RFUO: Same as RFU with drench of soya bean oil at the rate of 6ml/kg live weight at the start of the trial. MLU:Molasses (at up to 30% dietary DM inclusion in the diet) plus restricted grass and 50g urea/100 kg LWt. MLUO: same as MLU with drench of soya bean oil at the rate of 6ml/kg live weight at the start of the trial. A rumen supplement contained: 1.5% sulphur, 5% salt, 5% bone meal, 73.5% rice bran . Thirty growing cattle of 132 to 144 kg live weight were allocated to the 6 treatments . They were housed in individual pens so there were 5 replicates per treatment. The trial period was 90 days.

The growth rate and feed conversion rate of defaunated animals was improved over faunated ones. The introduced system of feeding grass with rice straw using urea and an oil drench resulted in more financial profit to the farmer than the system normally practiced.

Key words: cattle, grass, soya bean oil, rice straw, molasses, rice bran, urea,

Introduction

Strategies to develop animal production systems in the tropics, which are sustainable and applicable, must be based on locally available feed resources. Economic viability depends on achieving optimum level of animal performance with minimum inputs of costly and scarce concentrate and protein supplements. In Vietnam, rice straw is abundant in most provinces and molasses is widely available. Vietnamese and Australian researchers have found that molasses, a by-product of sugar production, is one such component that can replace cereal grains as a component in diets for beef cattle production. Molasses is traditionally used by farmers in Vietnam as a feed for pigs and cattle. This large quantity of molasses is available as a feed resource for raising animals.

In principle, it is possible to improve the feeding value of rice straw with a number of treatment techniques which have been developed (see review by Nguyen Xuan Trach 1998). It is therefore proposed to measure the response of growing cattle to the oil drench with a basal diet of molasses compared with rice straw. Recently, studies by Nguyen Thi Hong Nhan et al (2001, 2003) and Mom Seng et al (2001) have shown that the oil eliminated protozoa from the rumen and, as a result, the cattle grew faster

The hypotheses to be tested are that there will be positive effects of defaunation by soybean oil in the local conditions. The research should establish the basis background for an economical way of fattening cattle in Vietnam.

Materials and Methods

The experiment was carried out at the cooperative farm in Angiang where there were a lot of cattle for choosing.

Numbers of animals:

Five farmers, who traditionally fatten local "Yellow" x Sind breed cattle on rice straw and grass were identified in Angiang province. 30 local "Yellow" x Sindhi breed cattle of about 132 - 144 kg live weight were allocated to the 6 treatments at random within blocks. They were housed in individual pens so there were 5 replicates per treatment. The trial period was 90 days. The animals were vaccinated against foot and mouth disease and dewormed before the initiation of the experiment. They were fed totally in shed, drinking water and rumen supplement being available all the time

Treatments:

 The design was a 3*2 factorial arrangement of three basal diets (molasses, rice bran or rice straw) and with or without an oil drench (0 or 6 ml soya bean oil /kg live weight) to provide 6 treatments

• RF: rice straw without urea plus restricted grass (45+45% DM basis) and Rice bran (10 % of diet DM basis)

• RFO: Same as RF with drench of soya bean oil at the rate of 6ml/kg live weight at the start of the trial

• RFU: rice straw plus restricted grass (50 and 50% DM basis) + 50 urea/100 kg LWt

• RFUO: Same as RFU with drench of soya bean oil at the rate of 6ml/kg live weight at the start of the trial

• MLU:Molasses (at up to 30% dietary DM inclusion in the diet) plus restricted grass and 50 urea/100 kg LWt

• MLUO: same as MLU with drench of soya bean oil at the rate of 6ml/kg live weight at the start of the trial

All cattle were given a rumen supplement containing 1.5% sulphur, 5% salt, 5% bone meal, 73.5% rice bran .

Feeds and management

Rice straw was purchased from local farmers. The Hymenachne acutigluna grass was grown on the farms and harvested at about 30 days stage of regrowth. (Photo 1) . The soya bean oil was purchased in the market. The experimental cattle were weighed at the start and drenched with soya bean oil at a rate of 6ml/kg live-weight.

 

Photo 1: The Hymenachne acutigluna grass grown  by the farmers	Photo 2: Low-cost system of weighing the cattle

 

Measurements

The cattle were weighed on two consecutive days at the beginning, after 30 days, 60 days and after 90 days in the morning before eating (Photo2). During the trial, the feeds were weighed daily.  Residues were collected and weighed before the morning feed every day during the whole feeding trial period. Samples of feeds offered and refused were collected on a daily basis for each animal, bulked weekly, sampled within cattle and dried in a forced air oven at 70^o C to a constant weight. Samples were then ground using a laboratory hammer mill to pass a 2mm sieve and stored for later chemical analyses.

Economic analysis was made using partial budget analysis based on increased costs and increased returns of the treatments.

All the data were coded for subsequent statistical analysis using the general linear model software of Minitab (release13.2 ). Sources of variation were: treatments and error.
 

Results and discussion

Feed intake and growth rate

The proximate chemical composition of the  feed ingredients offered is in Table 1.

Feed intake and growth rate were highest on the molasses diet and lowest on the diet based on rice straw (Table 2). The oil drench led to increases in growth rate in the periods 30-60 and 60-90 days and in the overall trial (Figure 1). Feed conversion rate did not differ among diets but was improved by the oil drench (Figure 2). .

Table 2: Effects of different diets  combined with an oil drench on growth  in young crossbred cattle
	No- oil				Oil drench			Probability
	Molasses	Rice straw		Rice bran	Molasses	Rice straw	Rice bran	Diet			Oil	Diet*oil
Intake, kg DM/day
0- 30days	5.48	4.31		4.67	5.11	4.13	4.21	0.001		0.11		0.85
31- 60 days	4.92	4.04		4.5	5.23	4.3	4.73	0.04		0.33		0.9
61-90 days	4.89	3.9		4.47	5.24	4.32	4.44	0.02		0.33		0.74
Mean	5.09	4.08		4.54	5.19	4.25	4.46	0.007		0.79		0.9
Live weight, kg
Initial	132	136		143	134	144	137	0.51	0.83			0.61
30 days	148	150		159	153	161	153	0.7	0.6			0.4
60 days	164	163		173	175	177	169	0.9	0.2			0.4
90 days	177	173		185	194	191	185	0.84	0.07			0.39
Daily gain, kg
30 days	0.542		0.451	0.513	0.609	0.571	0.516	0.26	0.9			0.4
60 days	0.513		0.425	0.467	0.733	0.533	0.546	0.02	0.003			0.35
90 days	0.452		0.345	0.421	0.642	0.488	0.531	0.001	0.001			0.28
Average	0.502		0.407	0.467	0.661	0.521	0.531	0.001	0.001			0.07
Feed conversion rate (kg DMI/ kg weight gain)
30 days	10.3		9.53	9.13	8.55	7.63	8.34	0.54	0.04			0.76
60 days	9.68		9.52	9.86	7.03	8.82	8.85	0.54	0.07			0.55
90 days	11.5		11.8	11.0	8.05	10.1	8.36	0.26	0.001			0.58
Average	10.3		10.0	9.87	7.74	8.23	8.41	0.9	0.001			0.47

 

Figure 1: Effect of a drench of soya bean oil on the growth rates of cattle fed molasses, rice straw or  rice bran as supplements to grass		Figure 2: Effect of a drench of soya bean oil on the feed conversion of cattle fed molasses, rice straw or  rice bran as supplements to grass

Economic benefits

Based on changes in inputs and outputs due to the application of the feeding regime, and unit prices of the inputs and output at the time of experiment (Tables 3 and 4), a partial analysis was made on changes in costs and returns. as compared with the conventional practice. This indicated that despite the higher investment in the new technology, the farmers could make a profit equivalent to 22.8 % of the additional investment after 3 months thanks to the increase in growth rate of their animals.

Table 4:  Mean values for feed cost per kg live weight gain in the different treatment groups
	No- oil			Soya bean oil
	Molasses	Rice straw	Rice bran	Molasses	Rice straw	Rice bran
Feed cost (VND/ kg LW)	13158	4132	5782	9416	3531	4855

 

Conclusions

A single dose of soya bean oil (6 ml/kg live weight) to cattle fed grass supplemented with molasses, rice bran or rice straw,  improved feed intake, growth rate and economic profitability.
 

Acknowledgements

The authors wish to acknowledge the support for this research from the MEKARN Regional Project, financed by SidaSAREC of Sweden. This research was also supported by the International Foundation for Sciences (IFS), Stockholm, Sweden, through a grant to the second  author (Grant Agreement No B/3369-1). The authors are also grateful to the farmers' cooperative in An Giang province for providing the facilities and assistance during the trial.

References

Nguyen Thi Hong Nhan, Nguyen Van Hon, Ngu N T, Von N T, Preston T R and Leng R A 2001 Practical Application of Defaunation of Cattle on Farms in Vietnam: Response of Young Cattle Fed Rice Straw and Grass to a Single Drench of Groundnut oil. Asian-Aust. Journal Animal Science Vol. 14, No.4: 485-490.

Seng Mom, Preston T R and Leng R A 2001 Response of young cattle fed rice straw to supplementation with cassava foliage and a single drench of cooking oil. Livestock Research for Rural Development (13) 4: http://www.cipav.org.co/lrrd/lrrd13/4/seng134.htm

Nguyen Thi Hong Nhan, Nguyen Van Hon, Nguyen Trong Ngu, Nguyen Thi Thu Hong, Preston T R and Leng R A 2003: Effect of drenching with cooking oil on performance of local “Yellow” cattle fed rice straw and cassava foliage;  Livestock Research for Rural Development (15) 7 Retrieved September 30, 2005, from http://www.cipav.org.co/lrrd/lrrd15/7/nhan157.htm

Nguyen Xuan Trach and Mai Thi Thom 2004: Responses of growing beef cattle to a feeding regime combining road side grazing and rice straw feeding supplemented with urea and brewers' grains following an oil drench. Livestock Research for Rural Development. Vol. 16, Art. #53. Retrieved , from http://www.cipav.org.co/lrrd/lrrd16/7/trach16053.htm

 

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