THE FAMILY AND ITS POULTRY: AVERTING NUTRITIONAL DEFICIENCIES AND COMPETTITION
S.P.GUNARATNE
Veterinary Research Institute,
Gannoruwa,
Peradeniya,
Sri Lanka.
Summary:
Family flocks are heterogeneous in all aspects including management, feeding and nutrition. Three feed types (namely, scavenging feed, local supplement and formulated feed) are identified as the major feed resources used in family poultry production. These feed types, either singly or in combination, are used to produce poultry products which finally contribute to the social and economic well-being of the family. Scavenging feed is the most important feed resource in family poultry production as most of the family flocks in developing countries depend entirely on this valuable resource. The efficient utilization of scavenging feed resource is important for successful family flock production. For efficient utilization, an understanding is essential of the qualitative and quantitative aspects of scavenging feed resource, as well as its variation in different seasons and environments. This paper describes a method for determination of scavenging feed resource in a given environment, the measurement of its nutritional composition or deficiencies and suggestions for efficient utilization.
Local feed supplements are available in many environments and are used to feed the family poultry to supplement the scavenging feed resource. These supplements are mainly of agricultural, crop and industrial by-products origin. A complete list of such materials and availability in different environment will vary from village to village and country to country. However, their nutrient content can be obtained from the literature. A supplementation study carried out in Sri Lanka is discussed in this paper and concludes that the response to supplementation is always not positive, hence many factors need to be considered before deciding on the supplementation.
Formulated or commercial feed is used in small and medium scale, intensive family poultry units. The efficiency of village chickens in utilizing this feed under intensive management is discussed using results from an experiment which included village, cross bred and hybrid chickens allowed choice feeding under the same management condition. In this study, village chickens were less efficient in utilization of formulated feeds, in terms of performance and nutrient utilization efficiency, but a slight improvement was seen with choice feeding. Marked improvement in performance and nutrient utilization was seen with cross breeding.
Introduction
The world has two distinct poultry production systems; namely intensive and extensive. A highly commercialized intensive system with high inputs is no more a family operation and has little or no contribution to the life of the large rural population of the world. These large commercial operations are highly uniform in terms of all management aspects and are therefore less complicated to describe and operate. However, small poultry units, described as family poultry in this paper, have less uniformity in all aspects even in the terminology used to describe them. Some of the terms used are; Family poultry, Rural poultry, Backyard poultry, Village poultry, Village chicken, Scavenging village chicken, Extensively reared chicken, Free range chicken (poultry), Local chicken (poultry), Traditional poultry Etc. Although minor differences are found in systems listed above, there are some common features which distinguish them from the commercialized intensive units. These family poultry units require minimum inputs and directly contribute to the social and economic development of the family who rear them. They have little impact on environment and are highly integrated to the crop- livestock system for sustainability.
The purpose of this paper is to review the nutrition of family poultry; the qualitative and quantitative aspects of feed resources available and the management of feed resources for more efficient production. Work carried out in Sri Lanka is mainly discussed in relation to similar work in other countries.
For the convenience of discussion, some important characteristics related to nutrition of different chicken production systems in villages as described by Roberts (1999) is summarized below. These systems range from traditional scavenging to different levels of supplementation with formulated or commercial feeds.
1.Traditional scavenging system (1 to 10 hens): This is the simplest system where feed is scavenged from the surrounding environment and household refuse. Birds are left to scavenge during the daytime and only night shelter is provided. Low levels of supplementation with by-products of local crops and industries occur in some situations especially during cropping and harvesting periods with limited confinement during daytime. Most of the family poultry belong to this category.
2. Small scale intensive (10 to 50 hens): Small scale intensive units where birds are fed with by-products of local crops and industries. No formulated feed is used. Some housing is required.
3. Medium scale intensive (50 to 1000): Owners of these units generally have additional income from sources other than agriculture. Therefore, they can afford to feed birds with good quality formulated commercial feed in addition to by-products of local and regional crops and industries.
Some systems cannot be strictly classified into any of the above three systems as they are still in evolution. All systems, however, clearly indicate gradual but slow transition towards an intensive family units from more traditional scavenging system.
Scavenging feeds, local supplements and formulated feeds are three important feed components, which can be identified in any of the family poultry system. The scavenging feed is always free in terms of cost and the same is true for the local supplements in many situations. However, the use of formulated feed requires additional cost. These feed components, singly or in combination, contribute in varying degrees to the production of family flocks. However, the availability and utilization of scavenging feed resource is the main asset in family poultry production because this valuable feed is available absolutely with no cost, an advantage which no other production system. Scavenging feed resource is not utilized or is underutilized in many environments and thus contributes to environmental pollution. Other scavengers like stray dogs, cats, mongoose which are not beneficial to the rural community may utilize these feeds if they are not properly utilized by family poultry. Therefore, better utilization of scavenging feed resource base has many benefits and advantages. The knowledge of scavenging feed resource base, such as its composition, deficiencies, availability, seasonal variation is and is discussed below.
Scavenging feed resource and its utilization for family poultry production.
The feed is the most important item in modern commercial intensive poultry production, in terms of its contribution to the cost of production. In many situations feed cost account for about 60 to 90% of production cost depending on raw materials availability. This cost can be considered zero or negligible in scavenging chicken production. However, the importance of feed in scavenging chicken production cannot be underestimated due to its direct and indirect effects on many aspects of production. As the term “scavenging” imply, scavenging village chicken find its feed from surrounding environment. However, supplementation of these birds with kitchen refuse, household waste, agricultural by-products is not uncommon. Supplementation is sometimes essential during certain period of the year, when feed availability is limited.
The importance of scavenging feed resource base (SFRB) for village chicken production has been clearly demonstrated by Roberts & Gunaratne (1992) and Gunaratne et al (1993). The total biomass of the scavenging flock is determined by SFRB. If the biomass of the flock exceedes the carrying capacity of SFRB, some birds in the population, especially the weaker birds (young chicks), will die. Similarly, survival will be more when SFRB is more than the requirement of the flocks. A natural balance is seen between SFRB and biomass of the flock in a given environment unless some intervention is made. It is assumed that there are no competition from other scavengers for SFRB in that environment. If other scavengers interfere with scavenging feed resource, it should be taken into consideration when calculating SFRB.
SFRB is comprised of household waste, crop by-products, cleaning of gardens, fields and wastelands. In some environments SFRB is relatively constant throughout the year and in some others SFRB will fluctuate with factors such as seasonal rainfall, agricultural activities etc. It should also be noted that due to rapid urbanization, development projects and environmental changes are causing restrictions in availability and access to the SFRB. Land area available for scavenging and the distance a flock can travel to scavenge will depend on many factors such as flock size feed availability, population density, agricultural activities and predators etc. Further, behavioral studies have shown that some birds (e.g. unselected locals ) have better scavenging ability compared to others (e.g. crossbreds ). When crossbred birds were released to scavenging environment, they restricted their scavenging closer to the household.
If the capacity of the SFRB and the seasonal variations are known, more efficient strategies for production by flocks of scavenging village chicken can be developed. Roberts and Gunaratne (1992) described two methods for estimating the capacity of the SFRB for chicken in villages. In one method, the formula given below was proposed for calculation of SFRB. For this calculation, the measurement and identification of different components of the household waste and crop content is required.
SFRB = H X N where,
P N-X
H = amount of household waste/family/day (kg dry weight)
P = proportion of the crop content which is household waste as determined by visual inspection.
N = number of families in the community
X = number of families in the community which do not keep chickens
In the study of Gunaratne et al. (1993) the figures are: 0.200/0.720 x 1/0.500 x 365 = 203 kg dry weight/family/year. The amount of protein in the SFRB can be determined from analysis of crop content and the metabolizable energy (ME) can be determined by analysis of the crop content or by reasonable estimation. On this basis with 11.2% protein, and 3000 Kcal /kg the SFRB has 23 kg protein and 609 Mcal ME per year.
Alternatively, the SFRB can be calculated if the weight profile and constitution of the average flock is known, together with the growth rate and hen day production %. To the extent that there is feed available, the amount of feed consumed by the birds is determined by their energy requirement. The protein consumption and availability for maintenance, growth and egg laying is determined by the percentage protein in the diet. The daily consumption of the flock is the SFRB and can be calculated using the formula,
SFRB = Ej / Es
Where, j = the average number of birds of the family flock
Ej = the ME requirement for the daily maintenance and production of each bird per day (kcal/kg dry weight)
Es = the ME in the scavenging feed (kcal/kg dry weight)
‘j’ can be determined from a census of the family flocks.
‘Es’ can be measured or reasonably estimated from the crop content.
‘Ej’ can be calculated for each bird from the production data of growth rate and egg production, using a formula such as that of the National Research Council (1994), below,
ME/bird daily = W 0.75 (173-1.95T) + 5.5 W + 2.07 EE
Where; W= body weight (kg)
T = ambient temperature (C0)
W = change in body weight (g/day)
EE = daily egg mass (g)
An ambient temperature of 26C0 is assumed throughout.
The values for the SFRB calculated from published data from developing countries are;
475kg / year in Indonesia ( Kingston & Creswell, 1982)
390kg / year in Thailand ( Javiriyasopak et al., 1988)
195 kg / year in Sri Lanka (Gunaratne et al., 1992), which can be compared with the measured value of 203 kg, above.
High mortality is recorded in young chickens in villages but, if measures such as creep feeding or feed supplementation are undertaken to increase the survival of the chicks, then the mortality will only be transferred to another age group, unless the number of eggs incubated is planned to match the capacity of the SFRB. If the capacity of the SFRB varies seasonally then periods when it is high can be selected for activities such as hatching and rearing, and culling for consumption and sale can be undertaken in anticipation of a reduction in the capacity of the SFRB. On the other hand, if it is desirable to maintain the population through a lean period, then the appropriate feed supplement can be provided.
Alternative production systems can be compared e.g. Comparisons between egg and meat production, in order to optimize the nutritional return, and/or the cash return, from a SFRB of known capacity.
Nutritional value of SFRB
The nutritional value of SFRB may vary with the environment. In the study of Gunaratne et al (1993), analysis of crop content showed similar composition to that quoted by Prawirokusumo (1988), but the higher ether extract and lower crude fibre of 5.4% allowed more scope in choice of supplements. The proximate analysis of feed and crop content and the presence of substantial abdominal fat in all hens indicated that the availability of protein was a constraint on production in that environment. Protein rich materials such as earthworms, snails and insects were a minor proportion of the field diet, but young grass shoots, the large constituent, could have helped to redress the protein imbalance. The levels of calcium and phosphorus in the diets were very low, as were the levels in the plasma of scavenging chickens. The plasma levels of both Ca and P increased when village chickens were maintained under intensive system on a balance diet, but the Ca levels still did not reach that of commercial chickens under the same conditions (table 1).
Table 1: Plasma Calcium and Phosphorus levels in-groups of 15 village and commercial chickens
Chickens / Husbandry / Calcium mg/dl / Phosphorus mg/dlVillage / Scavenging / 10.412.46
P 0.001 / 2.470.41
P 0.001
Village / Intensive / 15.634.58
P 0.02 / 3.940.78
Commercial / Intensive / 19.613.02 / 3.590.77
If the low levels were constraints on production, then Ca and Phosphorus could be easily and cheaply provided in the form of shell grit and bone meal. Additional supplementation with a balanced ration would increase production further, but would be less efficient than if applied to commercial layers (Creswell and Gunawan, 1982), which can be successful in the scavenging system ( Huchzermeyer, 1973). In view of the high energy requirement of scavenging activities the final step to optimize the utilization of the SFRB could be to have a small number of hybrid layers in a pen, fed with a household waste supplemented appropriately and immunized as necessary. Such a system is unlikely to be culturally acceptable, and in any case it deprives the household of the benefit of the waste from those households which do not keep chickens.
Use of Local feed supplements in family poultry production.
Local supplements will include some of the components already included under scavenging feed such as household waste and agricultural, industrial and crop by- products reasonably large enough to have a significant role in the feeding of family flocks. These materials are also given different names, like nontraditional, or unconventional, due to less significance of these materials in the feeding of intensively reared livestock. Rural family flocks have a better access to these materials which can play an important role in their nutrition. Lists of such materials are available in different countries and their nutritional values can be easily obtained from published literature (Gohl,B.,1982). How to use these materials in combination with scavenging to improve efficiency is an important aspect in further improving the production from family flocks. Such a study carried out in Sri Lanka with supplementary feeding using a feed mixture prepared from local raw materials is discussed below.
Survival, growth and production in village chickens under four feeding conditions as listed below were studied for about one year.
- Control – Normal scavenging system
- Creep feeder – Household refuse disposed to creep feeder. The details related to design and construction of the creep feeder are available in Wickramaratne (1999). The purpose of creep feeding is to give young chickens preferential access to household refuse. The survival of young chickens and their growth rate is expected to improve with this intervention.
- Low supplementation – As 2 above + 35g of supplement per flock/day
- High supplementation – As 2 above + 25g of supplement /bird unit/day (bird unit or adult bird equivalent; calculated using a formula based on adult bird weight taken as one unit )
The composition of the supplement used in the study was an equal weight of fishmeal and expeller coconut meal with 2% DCP was mixed into the mash. The shell grit was offered in a separate container ad libitum to supply calcium. Level of supplementation was decided considering the nutrient requirement of flock and nutrient supply from scavenging feed resource base. Low level of supplementation was decided to redress the nutrient deficiencies in the scavenging feed resource base such as protein, calcium etc., hence the qualitative requirement of the feed was satisfied. In high level supplementation, both qualitative and quantitative deficiencies were covered and birds were receiving a balanced feed to perform optimally. The result of the study is discussed below.
Survival
The survival of the chicks and growers showed significant improvement with the introducing of the creep feeder (P 0.05) compared to control (table 2). Addition of supplementary feed to the household refuse further increased chick survival. High levels of supplementation had positive effect on chick survival compared to the low level of supplementation, although the difference was not significant (P05). There was a high correlation between supplementation and chick survival. The high rate of chick survival may be due to the preferential access to household waste for young birds and reduction in predator attacks as chicks remained near creep feeder.