Livestock Research for Rural Development 17 (6) 2005 Guidelines to authors LRRD News

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Productive performance of confined Pelibuey lambs fed a mixed diet based on agro-industrial by-products and crop residues

R Macedo and L A Aguilar

Facultad de Medicina Veterinaria y Zootecnia. Universidad de Colima
Km. 40 autopista Colima - Manzanillo. Tecomán, Colima, México. C.P. 28100


A study was carried out to determine the effect on growth and feed intake by lambs of a concentrate containing agro-industrial by-products and crop residues. Twelve recently weaned Pelibuey 82-day-old male lambs with an average BW of 16.9 ± 2.68 kg, were placed in individual pens and had ad libitum access to the diet. 

A significant curvilinear relationship (P<0.01) explained by the equation  Y = 0.0018x2 + 0.106x +16.9  (R2 = 0.999) characterized the growth curve of the lambs (Y=live weight; x is days on trial).  Overall average growth rate was 205 g/day; feed conversion was 5.21.

In conclusion, lambs fed a complete diet based on non-conventional feed resources showed a growth and feed conversion rate close to the genetic potential of the breed.

Keywords: Dry matter intake, growth, hair sheep, non-conventional feed resources

Comportamiento productivo de borregos Pelibuey estabulados con una ración conteniendo residuos de cosecha y subproductos agroindustriales


Se evaluó el comportamiento productivo de borregos Pelibuey en estabulación alimentados con una dieta integral, elaborado con residuos de cosecha y subproductos agro-industriales. Doce corderos con una edad y peso promedio de 82 y 16.92 ± 2.68 kg respectivamente, fueron colocados en corraletas individuales y alimentados ad limitum con la dieta.

Una ecuación curvilineal significativa (P<0.01) expliquó el crecimiento (Y = 0.0018x2 + 0.106x +16.9  (R2 = 0.999) la curva de crecimiento de los borregos durante el experimento (Y=peso vivo; x días en el ensayo). La tasa de crecimiento promedio fue 205 g/día, siendo la conversión alimenticia de 5.21.

Los corderos alimentados con una dieta integral, conteniendo recursos alimenticios no convencionales, mostraron tasas de crecimiento y conversión alimenticia muy cerca al potencial genética de la raza.

Palabras clave: alimentos no convencionales, borregos de pelo, crecimiento, conversión


Although agro-industrial by-products and crop residues are readily available in México, their use in sheep feeding is limited. Most systems of sheep production are almost exact copies of those practiced in industrialized countries, using the same diets based on grain. This management has exacerbated problems like the increase in the foreign exchange deficit as well as the alimentary dependency, due to high imports of grains (Preston 1995).

Previous studies showed fiber-rich, low-protein forages, and crop residues are the most abundant and appropriate feeds for ruminants in the tropics, as well as the feasibility of producing meat and milk in developing countries by feeding non-conventional feed resources (Owen 1994; Preston 1995). The present investigation was undertaken to evaluate the effect on growth and feed intake of confined Pelibuey lambs of a diet based on agroindustrial by-products and crop residues.

Materials and methods

Area description

The study was carried out in the Agroforestry and Agriculture Training Center (CECAF) in Tecomán, Colima, México, located at 18°58'43'' north latitude and 103°52'18'' west longitude and 33 m above sea level. Koppen´s climate classification is BS1(h')w(w)(i') described as semiarid with a rainy season during summer providing 750 mm a year. Dry season extends eight to nine months with an average temperature of 26 °C (García 1988).

Animals and management

Twelve recently weaned purebred Pelibuey 82-day-old male lambs, with an average BW of 16.9 ± 2.68 kg, were placed in individual pens and subjected to a dietary treatment. Fifteen days before the weaning, they were vaccinated against haemorrhagic septicaemia and pneumonia with a live tissue culture vaccine. De-worming and vitamins were administered at weaning, with albendazole (10 mg kg-1 BW) and with 1 ml of a vitaminic solution containing 500 000, 50 000 and 50 I.U of A, D3 and E vitamin, respectively.

Feeds and feeding

An experimental concentrate mixture was formulated with agro-industrial by-products and crop residues as the main ingredients. Concentrate and fresh clean water were provided ad libitum at all times. The composition of the concentrate and its chemical analysis are shown in Table 1 and Table 2.

Table 1. Composition of concentrate mixture



Mineral premix






Animal lard


Calcium carbonate


Rice políshing


Sorghum bran


Cowpea straw


Maize bran


Meat meal


Maize stover


Sugar cane molasses


Maize grain


Table 2. Chemical analysis of concentrate mixture (as fed basis)



Dry matter, %


Organic matter, %


Crude protein, %


Crude fiber, %


Ether extract, %


Nitrogen-free extract, %


Ash, %


Metabolizable energy, Mcal/kgDM*



Statistical analysis

 Live weight (LW) was recorded at the beginning and every seven days at the same time before feeding; feed intake was recorded daily. Trends in growth rate were analysed through the adjustment of a regression of live weight on trial (Cochran and Cox 1991).

Results and discussion

A significant curvilinear relation (P<0.01) explained by the equation Y = 0.0018x2 + 0.106x +16.9  (R2 = 0.999), characterized lamb growth rate, indicating that growth rate increased as the trial progressed (Figure 1). Thus the daily weight gain was 133 g from weaning up to day 21, followed by a higher growth rate (249 g per day) thereafter (Table 3).

Figure 1: Growth curve of Pelibuey lambs fattened on a complete diet based
on agro-industrial by-products and crop residues

The daily DM intake, expressed as a function of live weight, was high (mean of 4.1 kg/100 kg LW/day) with a tendency to decrease during the trial (Figure 2). The DM feed conversion was 5.21 on average (Table 3)

Growth performance was higher than reported by Pineda et al (1998) for confined hair sheep fed under tropical conditions.  They recorded a daily weight gain of 182 g in Pelibuey lambs fed a diet containing maize in addition to non-conventional feedstuffs such as guinea grass, poultry litter, molasses, coconut oilmeal, urea, salt and minerals. Also, Peralta et al (2004) fed Pelibuey lambs with a traditional diet based on maize (63%), soybean meal (15%), maize stover (20%) and minerals (2%), reporting a daily weight gain of 168 g. In the tropics, daily weight gains above 200 g have been mainly reported for crossbreds of hair sheep (Pelibuey and Black Belly) with long wool or synthetic breeds. Thus Pelibuey x Rambouillet - Dorset lambs gained 238 g per day (Pineda et al 1998). Likewise, Katahdin x Black Belly lambs showed 229 g of daily weight increase (Moscoso et al 1995).

Figure 2. Evolution of DM intake (kg DM/100 kg LW) in relation to the days on trial


Table 3. Productive performance of Pelibuey lambs fed a complete diet based on agro-industrial by-products and crop residues     




weight gain

Average dry matter intake (g/day)

Feed conversion
(g DM/g gain)

First 21 days






Last 35 days






Total (56 days)







Pelibuey lambs fed a diet based on agro-industrial by-products and crop residues as main ingredients, had an average growth of 205 g/day and DM feed conversion of 5.2.


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Received 13 June 2004; Accepted 24 May 2005; Published 1 June 2005

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