Effect of level of cassava hay supplementation and concentrate use on milk yield and composition

M Wanapat, A Petlum, O Poungchompu, P Rawlinson* and W Toburan

Department of Animal Science, Faculty of Agriculture, Khon Kaen University,
Khon Kaen 40002, Thailand
* Department of Agriculture, University of Newcastle upon Tyne, UK

Abstract

Four, mid-late lactation crossbred cows were used in a 4x4 Latin-square design. The treatments were: CON = control, without cassava hay (CH) supplement, and with a concentrate: milk ratio (C:M) of 1:2; CH1 = supplemented with 0.6 kg/hd/day CH and with a C:M ratio of 1:2; CH2 = supplemented with 1.2 kg/hd/d CH and with a C:M ratio of 1:3; CH3 = supplemented with 1.8 kg/hd/d CH and with a C:M ratio of 1:4. The feeding trial included four 21 day periods, during which feed samples were collected and milk yield recorded.

The results show that increasing levels of cassava hay resulted in significantly improved milk yields and composition, and reduced the amount of concentrate required per litre of milk, thus increasing net profit. The best performance was found in the group supplemented with cassava hay at 1.2 kg DM/hd/d with C:M of 1:3.

Key Words: Cassava hay, concentrate: milk ratio, milk, cattle

Introduction

Good-quality roughages for dairy cattle are scarce during the dry season in the tropics. The development and utilization of cassava hay as an on-farm feed has been recommended as a possible solution to this problem (Wanapat et al 1997; Wanapat et al 2000d). Feeding cassava hay resulted in improved milk yield and quality (Wanapat et al 2000a, 2000b). However, studies on the effects of different levels of cassava hay supplementation on the performance of lactating dairy cows are limited, which was therefore the objective of this experiment.

Materials and Methods

Four crossbred dairy cows in mid-late lactation were randomly allocated to four dietary treatments according to a 4x4 Latin square design. The treatments were as follows:

CON = control (without cassava hay (CH) and a concentrate: milk ratio (C:M) of 1:2
CH1 = supplemented with 1 kg/hd/d CH, and C:M at 1:2
CH2 = supplemented with 2 kg/hd/d CH, and C:M at 1:3
CH3 = supplemented with 3 kg/hd/d CH, and C:M at 1:4

The cows received concentrates which contained a high level of cassava root chips (Table 1). Urea-treated rice straw (5% urea in dry matter) was offered ad libitum. The animals were adjusted to the diets for two weeks prior to each 21-day feeding period, during which milk yield, feed samples and straw intakes were measured. Milk samples were analyzed for chemical composition. Feeds were analyzed for chemical composition and for condensed tannins (cassava hay) using the vanillin-HCl method.

Table 1: Composition of the concentrate mixture (% by weight)
Cassava root chips	85
Rice bran	10
Urea	3
Sulphur	1
Minerals	1

All data were statistically analyzed using the GLM procedure (SAS 1987) and treatment means were compared using Duncan’s New Multiple Range Test.

Results and Discussion

The values for composition of the feeds (Table 2) are in line with literature values for urea-treated rice straw and cassava hay (Chenost and Kayouli 1998; Wanapat et al 200b).

Table 2. Chemical composition of the experimental feeds (on % of DM basis except for the DM which is on “as fed” basis)
	DM	CP	Ash	NDF	ADF	CT g/kg DM
UTRS	53.7	7.6	17.5	80.5	56.6	-
Cassava hay	92.3	23.4	13.5	50.4	45.0	30.5
Concentrate	87.1	12.1	4.3	19.5	7.2	-
UT Urea-treated rice straw; CP Crude protein (N6.25); CT Condensed tannins*

Intakes of urea-treated rice straw were similar among treatments, but concentrate intakes were substantially reduced by increasing the level of cassava supplementation (Table 3). Total dry matter intakes were found to be similar, in the range 2.6 to 3.0% of live weight.

Table 3. Effect of cassava hay supplementation on the dry matter intake (kg/day) of lactating cows
	CON	CH1	CH2	CH3
Concentrate: milk ratio	1:2	1:2	1:3	1:4	SEM
UTRS	6.7	6.6	7.1	6.0	0.74
Cassava hay	-	0.6^a	1.2^b	1.8^c	0.01
Concentrate	4.0^a	4.4^a	3.4^ab	2.5^b	0.46
Total	10.7	11.6	11.7	10.3	0.94
abc Values in the same row with different superscripts differ(P<0.05), UTRS = urea treated rice straw; CH = cassava hay; CON = control

Milk yields were improved by cassava supplementation, despite lower levels of concentrate use (Table 4). Moreover, fat and protein percentages tended to increase with the level of cassava hay supplementation. The most significant result was that cassava hay supplementation enabled a reduction in the ratio of concentrate: milk, from 1:2 to 1:4. This finding is in agreement with earlier reports by Wanapat et al (2000a,b,d).

The decrease in the amount of concentrate fed by using cassava hay will usually lead to reduced costs of production, and hence to higher profits. There are related benefits from giving cassava hay which can act as a milk preservative through the action of thiocyanate in the milk derived from residual cyanide compounds contained in cassava hay (Wanapat et al 2000a). Cassava hay thus can have multiple functions as a component of dairy rations, providing not only protein but acting as a rumen enhancer, milk preservative and an anthelmintic agent (Netpana et al 2001).

Conclusions

Cassava hay supplementation resulted in improved milk yield and composition regardless of level of concentrate use.
For lactating cows fed on urea-treated rice straw as a basal roughage, the concentrate: milk ratio can be reduced from 1:2 to 1:4 with cassava hay supplementation.

References

Chenost M and Kayouli C 1997 Roughage Utilization in Warm Climates. FAO Animal and Health Paper 135. Rome

Netpana N, Wanapat M, Poungchompu O and Toburan W 2001 Effect of condensed tannins in cassava hay on fecal parasitic egg counts in swamp buffaloes and cattle. In: Current Research and Development on Use of Cassava as Animal Feed. (Editors: T R Preston, B Ogle and M Wanapat). Khon Kaen University, Thailand http://www.forum.org.kh/~mekarn/proc-cass/netp.htm

SAS 1987 SAS/STAT Guide for Personal computers, Version 6, Cary, NC: SAS Inc.

Wanapat M, Pimpa O, Petlum A and Boontao U 1997 Cassava hay: A new strategic feed for ruminants during the dry season. Livestock Research for Rural Development, 9 (2): http://www.cipav.org.co/LRRD/lrrd9/2/metha92.htm

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

Wanapat M, Puramongkon Tand Siphuak W 2000b Feeding of cassava hay for lactating dairy cows. Asian-Australasian Journal of Animal Science 13:478-482.

Wanapat M, Pimpa O, Petlum A, Wachirapakorn C and Yuangklang C 2000c Participation scheme of smallholder dairy farmers in NE Thailand on improving feeding systems. Asian-Australasian Journal of Animal Science 13:830-836.

Wanapat M, Pimpa O, Sripuek W, Puramongkol T, Petlum A, Boontao U, Wachirapakorn C and Sommart K 2000d Cassava hay: an important on-farm feed for ruminants. In Proceedings International Workshop on Tannins in Livestock and Human Nutrition (Editor: J D Brooker), ACIAR Proceedings No. 92, p. 71-74.

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