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RIDAFBOLETINES

INFPD Newsletter Vol. 9 No. 2, April - June 1999

The effect of feed energy level and particle size on performance of broilers under farmers management

Thomas J. Kaudia

In this study, the effect of feed energy level and particle size on the performance of broiler chicks under farmerės management was tested. Birds were reared under deep litter management system with wood shavings as the litter material. Broiler chicks were placed with ten farmers around Nairobi. Each farmer received 3,000 day-old broiler chicks. Farmers were managing the flocks after being trained. Eight different feed rations were used: four in the 21-day starter period (SP) and four in the finisher period (FP). For each rearing period, two levels of energy (high and low) and two modes of presentation (crumb and mash or pellet and mash) were considered. Feed and water were provided ad libitum, and birds were vaccinated against infectious bronchitis, Newcastle disease and Gumboro disease. Mature birds were slaughtered on day forty-two.

Better performances in terms of mortality, feed conversion ratio, production index number and gross profits per bird placed were obtained with broilers fed on mash rations compared to those birds fed on pelleted rations. The combinations of high-energy starter and high-energy finisher rations give also good results. It was concluded that mash rations should form the major component in broiler feed management under tropical conditions.

Key words: Energy, farmer management, feeding, mortality, particle size, performance, tropics

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Broiler farmers have a wide range of feed rations to choose from. These include pellets, mash, crumbs, low-energy, high-energy and special formulations as agreed between the miller and the farmer. Feed management still poses problems to broiler farmers worldwide, particularly in developing countries (Adegbola, 1988). Currently feed takes about 65-70% of the total cost of rearing broilers to market weight (Reddy, 1996). Research emphasis within the last three decades has been on fast weight gain without considering factors like climatic conditions, eating habits, availability of raw materials for feed manufacturing, exchanges rates, levels of farm inputs and knowledge in broiler rearing at farm level. Yet, these factors influence the rearing of broilers.

Feed costs are continuously increasing. This constitutes a major problem facing broiler industry in poor countries, especially in Africa. There is an urgent need to conduct research activities in order to find ways of optimizing the use of feeds and, thus, to reduce their costs. With the aim of contributing to overcome this constraint, the present trial carried out. This investigation focuses on feed management at farm level. The objectives of the study were:

1. to identify the best feeding programme suitable for rearing broilers in developing countries under farmersė management conditions;

2. to investigate disease and production factors associated with feed particle size and energy levels; and

3. to identify feeding strategies that give maximum economic returns.

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Thirty thousand Arbo Acres day-old chicks were used in this study. The chicks were purchased from a local poultry integrated firm in Kenya.

Eight different feed rations were used in this study. The rations were:
1. High-energy broiler starter crumb ration (HEBSC) with 13.40 MJ Metabolisable Energy (ME)/kg feed;
2. High-energy broiler starter mash ration (HEBSM) with 13.40 MJ ME /kg feed;
3. Low-energy broiler starter crumb (LEBSC) with 10.47 MJ ME /kg feed;
4. Low-energy broiler starter mash (LEBSM) with 10.47 MJ ME /kg feed;
5. High-energy broiler finisher pellet (HEBFP) with 11.72 MJ ME /kg feed;
6. High-energy broiler finisher mash (HEBFM) with 11.72 MJ ME /kg feed;
7. Low-energy broiler finisher pellet (LEBFP) with 10.05 MJ ME /kg feed; and
8. Low-energy broiler finisher mash (LEBFM) with 10.05 MJ ME /kg feed.

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All the different feed rations were purchased at prevailing market values. The market values were: Kenya Shillings (Kshs.) 1,640 per 70-kg-bag of HEBSC and HEBSM; Kshs. 1,440 per 70-kg-bag of HEBFM and HEBFP; Kshs. 1,200 per 70-kg-bag of LEBSC and LEBSM; Kshs. 1,100 per 70-kg-bag of LEBFP and LEBFM. (1US Dollar Į 75 Kenya Shillings).

The 30,000 Arbo Acres broiler chicks were randomly divided into ten batches of 3,000 chicks each and fed the following rations under farmersė management practices: Batch 1 (HEBSC-HEBFP), Batch 2 (HEBSC-HEBFM), Batch 3 (HEBSC-LEBFP), Batch 4 (HEBSC-LEBFM), Batch 5 (LEBSC-HEBFP), Batch 6 (LEBSC-HEBFM), Batch 7 (LEBSC-LEBFP), Batch 8 (LEBSC-LEBFM), Batch 9 (LEBSM-LEBFM) and Batch 10 (HEBSM-HEBFM). Broiler starter and finisher rations were each fed to birds for twenty-one days. There were one feeder for 50 birds and one drinker for 60 birds. Feed and water were provided ad libitum. Birds were on light for twenty-four hours. At night, light was provided using paraffin lamps. The stocking density was one bird per square foot. Heat was provided by charcoal stoves.

The experiment was participatory with farmers managing the flocks after being trained. Therefore there was no replication. Chicks were transported to the farms.

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Mature broilers were bought at live weight prices. First quality birds were bought at Kshs. 102 per kg live weight. Second grade birds were bought at Kshs. 80 per kg live weight. Birds were slaughtered at forty-two days of age. Carcasses were graded after dripping. The grading parameter was the dressed weight. The following grading scale was used: Springs (400-800 g), Grillers (800-1000 g) and Capons (more than 1000 g).

All birds were vaccinated against infectious bronchitis, Newcastle disease and infectious bursal disease.

Post mortem examination was carried out on all dead birds to determine the cause of death. Birds with distended belly full of water were classified under "water belly" ("ascites"). Dead birds lying on their back were classified under "Sudden Death Syndrome (SDS)". Any other cause of death was classified as "others". Dead birds were either burned and/or buried in disposal pits.

Production number index (PIN) is defined as the percent survivors multiplied by average body weight divided by the product of the multiplication between feed conversion ratio with age. The resulting figure is multiplied by 100 (Vest, 1995).

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Table 1 shows that overall mortality was higher in broilers fed on pelleted feeds, in comparison with those birds fed on mash rations. No effect of the energy level of the feed on mortality was observed. This is contrary to the findings of Shrek et al (1963) who reported a low mortality with pellet fed broilers. Higher mortality was due to ascites. This agrees with the findings of Dale (1994) and Maxwell (1990). They reported that feeding mash might result in minimizing ascites.

Some authors (Maxwell, 1990; Lee, 1997) indicate that ascites has also many other causes such as poor ventilation, use of some drugs such as furazolidone, vitamin E and selenium deficiencies, increased sodium (salt) in the drinking water or diet, disease, altitude, genetics and stress. The incidence of ascites is closely linked to the excessive water intake. Control of ascites through skip a day feed program (Maxwell and Robertson, 1997), may lead to severe coccidiosis challenge because birds tend to scavenge on the litter. This method may only be successful in well-managed farms typical in developed countries.

Mortality due to SDS ranged from 0.7 to 3.8 percent (Table 1). Higher incidence of SDS was also noted in birds fed on pellet compared to those fed on mash. This agrees with the results of Proudfoot et al. (1982) and further confirms that mash is the feed for tropical conditions where stress due to heat is a major poultry production problem (Adegbola, 1988).

Table 1: Total mortality and mortality due to ascites, SDS and other causes

Highest PIN values as well as gross profits per bird placed were obtained with the combinations of high-energy starter and high-energy finisher rations (Table 2). Good performance of mash rations may be due to the associated low mortality. This further emphasizes that livability is a key parameter in the profitability of rearing broilers. This has often been over-shadowed by the need for high body weight particularly where farmers are paid for it.

Table 2: Production parameters

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The following conclusions can be drawn from this study:

- For successful rearing of broilers in the tropics, mash rations ought to be included in the feed management program;

- More mash should be used during the second rearing phase after brooding to control ascites and SDS;

- An all mash feed ration is more suitable where feed management may be a limiting factor, especially in countries where the extension services do not exist or are not effective; and

- All stakeholders (breeders, hatchery managers, farmers, processors, consumers and policy makers) in the poultry industry should work together at all levels.

Therefore the following recommendations are made:

- Pellet and mash rations should be used together during a broiler rearing cycle;

- A standard minimum energy level in broiler feed rations should be set;

- Feed manufacturers should be compelled to indicate the feed energy level on the bag; and

- More research should be done to:

- determine causes in upsurge in mortality after introduction of finisher rations in a broiler rearing cycle;

- identify optimal energy levels in pelleted and mash feed rations to achieve minimum mortality in broilers under tropical and farmersė management conditions; and

- develop broiler rearing systems based on Hazard Analysis and Critical Control Points under farmersė management conditions.

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Adegbola, A.A. (1988): The structure and problems of the poultry industry in developing countries. African Farming, November/December 1988, pp. 11-13

Dale, N. (1994): Nutrition influences ascites in broilers. Poultry 2 (3): 40-43

Lee, P. (1997): Personal communication

Maxwell, M.H. (1990): Ascites in broilers. Poultry International, February 1990, pp. 32-38

Maxwell, M.H. and Robertson, G.W. (1997): World broiler ascites survey 1996. Poultry International, April 1997

Proudfoot, F.C., Hulan, H.W. and McRae, K.B. (1982): The effect of crumbled and pelleted feed on the incidence of sudden death syndrome among male chicken broilers. Poultry Science 61: 1766-1768

Reddy, C.V. (1996): Soya bean meal in poultry diets. Poultry International 35(5): 66-70

Shreck, P.K., Sterrit, G.M., Smith, M.P. and Stilson, D.W. (1963): Environmental factors in the development of eating in chicks. Animal Behaviour 11: 306-309

Vest, L. (1995): Posthatch chick holding time and broiler performance. Co-operative extension service, The University of Georgia, USA.

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