Feedlot performance of yearling steers previously maintained on different crop residue/supplementation regimes

M B Olayiwole & S A Olorunju
National Animal Production Research Institute, Ahmadu Bello University, P.M.B. 1096, Zaria - Nigeria

Abstract
Introduction
Material and methods
Results and discussion
References

Abstract

Forty two Bunaji and Friesian/Holstein crossbred yearling steers averaging 192 kg liveweight were randomly assigned to 6 Phase I treatments: dry grain sorghum stover; dry grain sorghum stover plus groundnut cake; dry grain sorghum stover plus urea-molasses; untreated grain sorghum stover silage; untreated grain sorghum stover silage plus groundnut cake and urea-molasses treated grain sorghum stover with additional urea-molasses supplement. After the treatment study lasting 56 days all the steers were placed on a Phase II feedlot diet, consisting of dry grain sorghum stover and a concentrate mixture, for 42 days.

In Phase I ensilage significantly (P<0.01) improved dry matter intake per head per day but there was no economic advantage in overall performance. Supplementation with limited quantities of groundnut cake or urea-molasses maintained liveweight.

In Phase II the steers, in their respective groups, maintained their relative and significant differences (P<0.05) in feed intake per head/day but when expressed in intake per metabolic liveweight the differences were not significant. There were no significant differences in liveweight gains between groups. The applicability of the results to the agro-pastoralist system of cattle production and to fattening enterprises is discussed.

Introduction

Over seventy percent of Nigeria's national herd is located within the Sudan and Sahel zones. The transhumant ruminant livestock in these areas derive about 69% of their annual dry matter intake from upland savanna (including browse material), 13% from flood plains and 18% from crop residues. In terms of nutritional availability, the critical months of the year are December, January, February, March and April when cattle obtain 91, 113, 79, 130 and 112 gram/day digestible crude protein respectively from their total feed intake (Van Raay et al, 1974). A summary of reports (Adegbola and Onayinka 1968; Egunjobi 1970; Akinola 1974 and 1983; de Leeuw 1977; Fricke 1979; Awogbade and Famoriyo 1982) on range and feed resources inventory suggests that under the existing level of grassland management there is inadequate feed to sustain the present ruminant population of about 14.5 million animal units (A.U.). Table 1 gives the area of grazing land, herb-age yield and carrying capacity of Nigerian Savannah. However, there is a tremendous potential from cereal and legume crop residues which Reddish and Scarr (1986) estimated to be about 50 million tonnes annually. Most of this material is presently wasted through burning, improper feeding and termite attacks.

Table 1. Grazing lands, herbage yields and carrying capacity of Nigerian Savanna.

Vegetation Zone	Estimated grazing land area (km² x 1000)	Annual rainfall (mm)	Herbage dry matter yield (t/ha)	Grazing period (days)	Carrying capacity (ha/A.U.)*
Derived Savanna	38.30	1275-2030	6.0-18.0	300-330	0.4-0.83
Southern Guinea Savanna	97.41	1140-1520	2.0-6.5	270-300	1-4
Mambilla Plateau	4.74	1800	4.0-7.0	360	2-4
Northern Guinea Savanna	106.3	1020-1270	2.0-4.5	210-240	3-5
Jos Plateau	8.53	1140-1450	1.5-4.0	240	6-9
Sudan Savanna	161.4-180.4	510-1020	0.7-2.5	120-160	8-12
Sahel Savanna	46.62-27.62	300-650	0.5-1.5	90-120	10-14

I Animal Unit = 300 kg liveweight requiring a daily herbage dry matter intake of 7.5 kg (at 2.5 kg per 100 kg body weight).

The nutritive value of the crop residues could be enhanced through physical and/or chemical treatment and/or supplementation with concentrate agro-industrial by-products or forage legume. But the quantity and quality of feed should satisfy the requirement for the type of production (maintenance, growth, lactation or draft) and the feeding regime imposed should be based on economic advantage.

In some cases it might be economically justifiable to offer sub-maintenance diets to non-producing animals during the dry season and accept loss of liveweight, if the cost of supplementary feeds is not economical.

The objective of the study was to look at effective utilization of sorghum stover, a common by-product in the agro-pastoralist farming system, and to assess the carry over effect at the fattening phase using sorghum stover and a concentrate mixture.

Material and methods

The study was carried out at the National Animal Production Research Institute (NAPRI), Zaria, Nigeria located in Northern Guinea Savanna on latitude 11°11'N and longitude 7°38'E. The average annual rainfall is 1050 mm falling between June and September.

Forty two Zebu x Friesian/Holstein crossbred steers, average age 24 months and 190 kg liveweight, were randomly assigned to 6 treatments of 7 animals each based on age and liveweight; using balanced group continuous trial methods as described by Lucas (1974). The study covered two phases - maintenance and fattening. The 6 treatments imposed in the first trial are given in table 2.

The steers were individually penned and fed ad libitum twice daily at 0800 hrs and 1500 furs. Records of voluntary feed intake were kept during the 14-day preliminary and experimental periods. All the steers were weighed weekly. At the end of the experimental period of 60 days, a digestibility study of the 6 diets was conducted using the total collection technique.

The second phase of the study was carried out on the steers from the phase one experiment to monitor their performance on better feeding under feedlot management. This simulates the situation in the dry Sudan and Sahel zones where a feedlot operator purchases animals of different body weight from differently managed herds. The forty two steers, retained in their previous groups, were allowed free grazing and exercise for 7 days before the commencement of the second phase. They were fed in individual pens to appetite for an adjustment period of 14 days and subsequently for 60 days on a concentrate mixture and dry, untreated sorghum stover as the only roughage (Table 5). Water and mineral salts were offered ad libitum. Daily voluntary feed intake and weekly liveweights were recorded. A digestion trial of the experimental diets was conducted with wether sheep.

Table 2. Composition of the 6 experimental diets fed in Phase I

Treatment
No.	Experimental Diets
1.	Ad libitum sorghum stover + Mineral Lick.
2.	Ad libitum sorghum stover + 0.45 kg groundnut cake + Mineral Lick.
3.	Ad libitum sorghum stover + 1% Molasses + 0.5% Urea + Mineral Lick.
4.	Ad libitum untreated sorghum stover silage + Mineral Lick.
5.	Ad libitum untreated sorghum stover silage + 0.45 kg groundnut cake + Mineral Lick.
6.	Ad libitum Urea - Molasses treated sorghum stover silage + 0.5% Molasses + 0.25% Urea + Mineral Lick.

Results and discussion

The chemical composition of the experimental diets in Phase one is given in table 3. In the Phase I trial, (Table 4) it was found that ensilage significantly (P<0.01) improved dry matter intake per head per day by 26%, but intake per metabolic body weight improved by 41 percent. This could be attributed to a faster rate and better digestion of stover silage compared to dry stover possibly due to a better rumen ecosystem resulting from the attributes of microbial products of ensilage.

Supplementation with groundnut cake (treatments 2 and 5) resulted in a significant (P<0.05) improvement in dry matter intake. This was expected as energy and nitrogen supplied could have been used to meet part of the rumen microbial requirements, and concomitantly those of the host animal in the form of microbial and escape protein (Van Soest 1982). Although addition of nitrogen and energy in the form of urea and molasses (treatments 3 and 6) depressed dry matter intake per head per day by 8% (Table 4), their influence appeared to have a significant associative (P<0.05) effect on feed efficiency. The depressant influence on dry matter intake of urea-molasses supplement was comparatively higher on dry sorghum stover-based diet (which consistently had the lowest intake-Table 4) than on ensiled sorghum stover. This suggests a positive associative interaction between the basal diet and urea-molasses supplement probably due to ensilage effect. However, significant superiority of ensilage observed in dry matter intake had no corresponding effect on liveweight gain. The same trend was observed in the associative effects of ensilage and sources of energy/nitrogen.

Table 3. Composition of experimental diets in Phase one. (% Dry Matter)

	TREATMENT No's
	1	2	3	4	5	6
Dry Matter	92.81	80.00	76.00	56.90	67.22	54.10
Crude Protein (N x 6.25) %	4.75	8.20	6.76	4.43	7.50	6.57
NDF %	82.82	62.57	65.99	82.63	74.68	63.94
Non-CWC %	17.18	37.48	34.01	17.32	25.32	36.06
Hemicellulose %	28.75	24.43	24.22	28.68	27.22	22.00
ADF %	54.07	38.07	41.77	54.00	47.46	41.94
Cellulose %	46.36	32.16	35.81	45.98	40.29	35.83
Lignin %	7.72	5.91	5.96	8.01	7.17	6.11
Ash %	6.11	13.12	7.01	8.22	10.77	7.71

Table 4. Performance of steers fed six experimental diets in Phase I

	TREATMENT No's
	1	2	3	4	5	6	S.E.D.
Total DM Intake/Head/Day (kg)	2.76	3.55	2.32	3.48	4.87	3.16	0.091
Voluntary DM Intake g/kgW0.75/Day	49.31	71.29	44.52	69.67	92.02	65.40	1.881**
Mean Daily Liveweight change (kg)	-0.059	0.590	0.671	0.404	0.114	-0.236	0.286*
Feed efficiency (Feed/gains)	-0.997	2.436	1.624	5.984	-4.062	1.03	2.108**
DM digestibility (in vivo)	52.36	48.43	30.10	52.36	60.54	45.33
Crude fibre digestibility (in vivo)	67.20	40.66	35.77	73.70	54.32	63.09

* significant at 5% level
** significant at 1% level

Considering the labour and other inputs required in making silage from sorghum stover, ensilage does not appear to offer either biological or economic advantage. Supplementation of dry sorghum stover with either urea-molasses or limited amount of oil cake could support liveweight maintenance and some productivity during the dry season when rangeland is dry, bare and burnt.

In Phase II study, which was intended to simulate a situation where animals previously under different feeding regimes and management were purchased for feedlot operation, there were significant (p<0.05) differences in the overall dry matter intake per head per day in favour of treatments 2, 5 and 1 which, apart from group 2, had the lowest intake in Phase I. Mayer et al (1965) obtained relative higher intake of high energy feed in animals that had previously been placed on restricted feeding. However, when the same data were expressed on intake per unit metabolic body weight, there was no significant difference over the whole period. Treatments 3 and 6 which suffered depressed influence of urea-molasses supplementation during Phase one continued to show lower dry matter intake per head per day but intake per metabolic body weight was just slightly lower in the fattening phase as well and had the best feed conversion rates (table 6). This suggests that those treatments which in the earlier study had reduced intakes, continued to have reduced feed consumption during the fattening phase as well as achieving similar or better results. A similar observation was made by Ledger (1973) but under a restricted intake of balanced diets.

There was no significant difference in average daily liveweight gain between treatment groups except for treatment one which had superior (P<0.05) liveweight gain over the remaining treatments. It is possible, as was observed by O'Donovan (1984) that under-nourishment previously suffered by this group probably resulted in a compensatory liveweight gain when later fed ad libitum on a high energy diet (Table 6). However, the overall average daily liveweight gain was similar to that reported in the same environment under feedlot management (Olayiwole et al, 1973; 1981). By implication, the economic advantage and increased meat output are significant. Thus it can be hypothesized that if about 698,000 out of about 1.2 million cattle slaughtered annually in Nigeria are put on feedlot diets their body weights could be increased by 100 kg per head over a period of 110 days. This would result in an increase of about 69,800 tonnes of beef annually.

On the basis of ratio of liveweight gain per unit feed intake (reciprocal of feed efficiency), the two treatments (1 and 4) on basal diets appear to have had the best biological and economical advantage followed by treatments 6, 2, 3 and 5 in that order.

Studies on ruminant livestock ownership profile in the Sudan and Sahel zones (Fricke 1979) showed that 61.5 and 35% of the total population are in the hands of sedentary agro-pastoralists in the rainy and dry seasons respectively. This integrated crop and livestock production system ensures a reasonable tonnage of crop residues. Hence, supplementing these with agro-industrial by-products is one of the cheap and convenient ways to at least maintain body weight and a marginal productivity in the dry season. A feedlot operator who buys his cattle at the end of the dry season when the animals are at their lowest weight and poorest condition, would benefit both in reduced time and food consumption from compensatory growth.

Table 5. Chemical composition (%DM) and digestibility coefficients of the ration fed for the 60 days fattening period

	DM	CP	EE	CF	NFE	ASH
Concentrate Mixture*	74.10	21.48	9.01	9.43	56.45	3.63
Sorghum Stover	90.70	2.76	1.09	38.25	52.94	4.96
In vivo digestion coefficients	71.25	70.04	88.90	54.71	77.10	-

* Mixture of sorghum grain (41%), groundnut cake (15%) and undelinted, undecorticated cotton seed cake.

Table 6. Feedlot performance of steers fed sorghum stover and a concentrate mixture (given in Table 5)

	TREATMENT No's
	1	2	3	4	5	6	S.E.D
Voluntary DM Intake/Day (kg)	5.50	5.68	5.31	5.39	5.58	5.34	0.132*
Voluntary DM Intake g/kgW0.75/Day	100.72	106.83	101.44	104.39	102.27	101.87	2.750
Mean daily liveweight gain (kg)	1.498	0.904	0.744	1.090	1.097	1.159	0.241*
Total liveweight change (kg)	49.57	40.29	44.57	45.86	40.14	40.86	5.133
Mean final liveweight (kg)	228.29	219.43	216.71	213.42	227.00	211.00	12.069
Mean Initial liveweight (kg)	178.71	179.14	172.14	167.57	186.86	170.14	9.893
Feed efficiency (Feed/gain)	4.24	4.75	2.85	5.60	6.72	2.81	1.957
Gain/Feed ratio	0.27	0.16	0.15	0.21	0.14	0.22	0.046**

* Significant at 5% level
** Significant at 1% level

The results of the trials indicate that the weight losses incurred during the maintenance phase do not adversely affect the animal performance of the feed lot stage. It may be inferred from the results obtained that steers could be maintained on sorghum stover with added limited quantities of protein and energy sources under intensive or semi-intensive management. There should also be adequate and regular supplies of water and mineral salts.

It is uneconomic for a grazier to sell his animals at the end of the dry season when they are in the poorest condition; he should take advantage of compensatory gain and economic efficiency. On the other hand, a fattener would capitalise on both the biological and economic advantage in buying his animals for fattening during and at the end of the dry season in these regions.

References

Adegbola A.A. and Onayinka B.O. 1968. The management and improvement of natural grasslands in Nigeria. Nigerian Agricultural Journal 5: 4-6.

Akinola J.O. 1974. Grassland research in Nigeria - Survey with recommendations. Nigerian Journal of Animal Production. 1: 162-168.

Akinola J.O. 1983. Grassland improvement and management in Nigeria. Invited lecture - ILCA/FAO/UNESCO/COMMSEC course in Tropical Rangeland Management Methodology, Addis Ababa, Ethiopia. 1983.

Awogbade and Famoriyo S. 1982. Nomadic land resource use and beef production in Nigeria. Beef Production in Nigeria Proceedings of the National Conference on Beef Production July 27-30, pp 427-454.

de Leeuw P.N. 1977. Animal nutrition and livestock development in the Nigerian savanna region. Proc. Conference. Aftermath of 1972-74 Drought in Nigeria, Bagauda, 1977. Ed. G. Jan van Apeldoorn, pp. 117-126.

Egunjobi J.K. 1970. Savanna burning, soil fertility and herbage production in two derived savanna zones of Nigeria. Wild life Conservation West Africa Proceedings 7th Biennial Conference pp. 52-58.

Fricke W. 1979. Cattle husbandry in Nigeria. A study of its ecological conditions and socio-geographical differentiations. Heildelberger Geographische Arbeiten, Heft. 52. In Selbstvertag des Geographischan Institutes der Universitat Heidelberg.

Ledger H.P. 1973. An evaluation of the efficiency of compensatory growth. World Conference on Animal Production, Melbourne, Australia, May 22-30, 1973. pp. 543-550.

Meyer J.H.; Hull J.L.; Weitkamp W.H. and Bonilla S.E. 1965. Compensatory growth responses of fattening steers following various low energy intake regimes on hay or irrigated pasture. Journal of Animal Science 24, 29-37.

O'Donovan P.B. 1984. Compensatory gain in cattle and sheep. Nutrition Abstracts and Reviews 54, 389-410.

Olayimole M.B.; Ahmed M.B. and Donald Bell T. 1975. Feedlot performance and carcass characteristics of steers fed higher energy rations. Nigerian Journal of Animal Production 2, 207-276.

Olayiwole M.B.; Buvanendran V.; Fulani I.J. and Ikhatua U.J. 1981. Intensive fattening of indigenous breeds of cattle in Nigeria. World Review of Animal Production 17, 71-77.

Reddish P.M. and Scarr M.J. 1986. Subsidiary Industries for the Livestock sub-sector. Paper presented at the 11th Annual Conference, Nigerian Society for Animal Production. Ahmadu Bello University, Zaria. April 1986.

Raay H.G.T. and de Leeuw P.N. 1974. Fodder resources and grazing management in a savanna environment. An ecosystem approach. Samaru Res. Bull. 224. (ISS Occasional Papers No. 45. 25 pp. Institute of Social Studies. The Hague).