Intensive production from African hair sheep fed sugar cane tops, multinutritional blocks and tree foliage

Intensive production from African hair sheep fed sugar cane tops, multinutritional blocks and tree foliage

* Instituto Mayor Campesino (IMCA), AA116 Buga, Valle, Colombia,
** Convenio Interinstitucional para la Producción Agropecuaria en el Valle del rio Cauca (CIPAV), AA7482, Cali, Colombia

A flock of African hair sheep of approximately 80 ewes and 4 rams of the local "pelibuey" or "West African" breed, in all stages of the reproduction cycle, had free access to chopped fresh sugar cane tops and/or King grass forage (offered amounts were 150% of consumption to facilitate selection), a multinutritional block (10% urea, 50% molasses) and a mixture of poultry litter and rice polishings (ratio of 9:1). They also received fresh foliage of Gliricidia Sepium at the rate of 3 kg/100 kg liveweight/day. The offspring had the same nutritional regime as their dams (given in a creep feeder to which the ewes did not have access). Weaning was at 12 kg bodyweight and slaughter (or first mating) at 30 kg. The overall dry matter intake was 4.5% of liveweight of which the forage component (cane tops and King grass) represented 72% of the total dry matter, the supplements of gliricidia (9.3), poultry litter (10.6), rice polishings (1.0) and multinutritional blocks (6.2) accounting for the remainder. The mean lambing interval was 284±85 days (n=44), the litter size 1.16 (n=144), birth weight 2.32±0.52 kg (n=167), pre-weaning growth rate 106±34 g/day (n=84) for a weaning age of 129±46 days. Mortality perinatal was 5.5% and from birth to weaning 10.4%.

KEY WORDS: African sheep, sugar cane, multinutritional blocks, reproduction, growth, feed intake, legume trees

The hypothesis that sugar cane represents a logical alternative to cereals as the basis of intensive livestock production in the tropics (Preston 1980; Preston 1988) is based on the extremely high productivity and energetic efficiency of sugar cane, the comprehensive knowledge of its agronomic needs at the level of the producer, and the ease with which the biomass can be separated into soluble and fibrous carbohydrate fractions. This latter characteristic has made it possible to develop feeding systems for both monogastric and ruminant animals, as well as providing a valuable residue (the dry leaves and trash) which can be used as a mulch or as fuel (Preston 1990).

The use of sugar cane juice as an alternative to cereal grains in feeding of pigs on smallholder farms is already a commercial proposition in several tropical countries (Sarria et al 1990). However, if more efficient use could be found for the fibre-rich residues (tops and bagasse), presently largely wasted, the cost of production of pig and poultry feeding on the juice would be reduced, since the cost of growing the cane would be spread over both monogastric and ruminant feeding systems. This would stimulate both production and consumption of pig and poultry products inis part of a broader project which aims to develop sustainable production systems for small ruminants, based on cane tops and bagasse, strategically supplemented with multinutritional urea-containing blocks and leaves and green stems from forage trees. African "hair" sheep are the chosen species for this programme in view of their ready adaptation to the humid tropics, their biological and economic superiority over large ruminants because of higher rates of production and reproduction, relative to investment costs , and the ease of confining them in low cost structures. These features are the basis for believing that intensive sheep production could be more appropriate at smallholder farmer level than cattle production.

The study was carried out in the livestock facilities of the Instituto Mayor Campesino (IMCA), in Buga, Valle (1000 m above sea level, mean temperature 24 ^oC, rainfall 1200 mm/yr).

A flock of African hair sheep of approximately 80 ewes and 4 rams in all stages of the reproduction cycle had free access to chopped fresh sugar cane tops and/or King grass forage (offered amounts were 150% of consumption to facilitate selection), a multinutritional block (10% urea, 50% molasses, 10% CaO, 10% minerals, 20% wheat bran) and a mixture of poultry litter and rice polishings (ratio of 9:1). They also received fresh foliage of Gliricidia sepium at the rate of 3 kg/100 kg liveweight/day. The offspring had the same nutritional regime as their dams (given in a creep feeder to which the ewes did not have access). Weaning was at 12kg bodyweight and slaughter (or first mating) at 30 Kg. The animals were confined permanently in partially roofed sheds open at the sides, on deep litter composed of sugar cane bagasse and feed residues. The sheep were not vaccinated nor were they treated against internal or external parasites.

The sheep were of the local "pelibuey" or "West African" breed, common in México and Cuba, as well as in Colombia, and descended apparently (Gatenby 1986) from the West African Dwarf type imported along with slaves from West and Central Africa during the 17 th and 18 th centuries.

Normal production parameters (bodyweight, feed intakes, lambing rates) were recorded.

Results are available for the feed intake of the flock from 1 July to 31 December 1990 (Table 1). Table 1: Mean values for the feed intake of the flock of Tropical hair sheep during the period 1 July to 31 December 1990.

Table 1: Mean values for the feed intake of the flock of Tropical hair sheep during the period 1 July to 31 December 1990.

Diet components	Fresh basis	Dry basis

Feed intake (kg/d):
Gliricidia	0.670	0.138	(9.3)*
Sugar cane tops/King grass**	4.858	1.074	(72.4)
Multinutritional block	0.104	0.092	(6.2)
Poultry litter	0.176	0.158	(10.6)
Rice polishings	0.018	0.016	(1.0)
Mineral salt	0.005	0.005	(0.3)

Total intake		1.483	(100)
% of liveweight		4.493

* Figures in brackets are percentages of the total diet (DM basis)** King grass was given when there were shortages of cane tops

The forage component (cane tops and King grass) represented 72% of the daily dry matter intake, the supplements of gliricidia, poultry litter and multinutritional blocks accounting for the remainder. Overall dry matter intake at 4.5% of liveweight is at the high end of the range of expected values for tropical hair sheep (see Gatenby 1986). According to Preston and Leng (1987) a high intake is an indication that the diet is giving rise to an adequate balance of nutrients at the sites of metabolism. It is reasonable to conclude therefore that the supplementation employed, accounting for less than 30% of the total diet dry matter, was appropriate in securing an optimum balance of nutrients for both rumen microorganisms and the animal.

The productive and reproductive performance of the sheep flock are summarised in Table 2. The data relate to the period December 1988 to March 1991

There appear to be few data in the literature on the reproductive rate and pre-weaning performance of tropical hair sheep of the type used in this study. The mean lambing interval of 284±85 days (n=44) is in the centre of the range (210-365 days) reported by Wilson et al (1981) for a sheep flock in Kenya but longer than reported in Ecuador for crosses of Barbados Black Belly and West African sheep (220 days)(Gonzalez and Riera 1989). The litter size of 1.16 (n=144) is similar to reports for Pelibuey sheep in Yucatán, México (1.17 by Castillo Rojas et al 1972; 1.20 by Gonzales Reyna and Alba 1978), but less than reported by Gonzalez and Riera (1989) in Ecuador (1.37). The birth weight was 2.32±0.52 kg, slightly less than in the Ecuador study (2.88 kg). The pre-weaning growth rate of 106±34 g/day for a weaning age of 129±46 days can be compared with the mean of 117 g/day for Blackhead Persian lambs in Brazil weaned at 112 days (Figueiredo et al 1982). Table 2: Productive and reproductive parameters of the flock of African Hair sheep during the period from December 1988 to March 1991

Table 2: Productive and reproductive parameters of the flock of African Hair sheep during the period from December 1988 to March 1991

	Mean value	Standard deviation	n

Liveweight (kg)
Birth	2.32	0.52	167
Weaning	14.9	2.62	84

Weight gain to weaning (g/day)	106	33.6	84

Age at weaning (days)	129	45.5	84

Lambing interval (days)	284	85.3	44

Litter size*	1.16		144

Lambs born/ewe/year**	1.49		44

Mortality (% all births)
Perinatal	5.5
Birth to weaning	10.4

* Number of lambs born per parturition
** Mean number of lambs born per ewe per year

According to Gatenby (1986), mortality between birth and weaning at 150 days in traditionally managed flocks in the tropics is typically between 10 and 30%. The value in the present study of 10.5% is thus at the low end of this range. The perinatal death rate of 5.5% is also less than the 20% described by Selaive et al (1980) in commercial flocks in Brazil.

The favourable health status of the flock is noteworthy when it is considered that there was no chemical or biological control of any disease. It can be ascribed almost certainly to the management and feeding system providing a more favourable environment than the open range to which most reported data relate.

The acceptable levels of productive and reproductive performance of the African hair sheep recorded in this study substantiate the hypothesis advanced by Leng (1990) that diets based on forages of low to moderate digestibility can support adequate levels of animal performance provided that supplementation is directed towards balancing the nutrients presented for metabolism.

The good health status of the flock in the absence of chemical or biological disease control treatments, partly reflects the known hardiness of African hair sheep but is also almost certainly due in large part to the confinement system.

This study was supported partially with funds from the FAO/IAEA Coordinated Research Programme on "Development of Feed Supplementation Strategies for improving ruminant productivity on Smallholder Farms in Latin America" (Research Contract No: 5846/RB), the International Foundation for Science (Research grant: B/1214-1), the Catholic Organization for Development Cooperation (CEBEMO) and the Fondo DRI. The authors are indebted to the Director of the Instituto Mayor Campesino (IMCA) for providing the facilities for carrying out this work.

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