Effect of feed selection and nutrient intake on the production performance of local and improved laying hens on small farms under scavenging conditions

Nguyen Thi Thuy and Brian Ogle¹

College of Agriculture, CanTho University, CanTho, Vietnam
nthithuycn@ctu.edu.vn
¹ Department of Animal Nutrition and Management, Swedish University of Agricultural Sciences, Uppsala, Sweden.

Abstract

An on – farm experiment was conducted at Binh Yen Hamlet, Long Hoa Village, Cantho Province in the South of Vietnam. A total of 60 Tam Hoang (TH) and 60 Tau Vang (TV) layers were equally divided between 6 small farms (10 TH and 10 TV on each) and were followed for 20 weeks of the laying period. The hens were allocated at random to 2 treatments in a 2 * 2 factorial experiment. The first factor was breed (Tam Hoang and Tau Vang), and the second factor diet, including: Mixed diet including maize meal, fish meal and roasted soya bean meal and with a supplement of oyster meal and bone meal; Separate diet, including the same feedstuffs but supplied separately in 3 feeders, and with oyster and bone meal mixed together with the maize meal. There were thus 4 treatments with 6 replications (farms) and with 5 birds per experimental unit (pen) and in total 20 hens per farm.

Daily dry matter (DM), crude protein (CP) and metabolisable energy (ME) intakes were 21 % higher for the improved Tam Hoang hens compared with the local Tau Vang hens. The hen–day production and mean egg weight were significantly different between breeds (P<0.001) and for the Tam Hoang were 30.1 % and 43.5 g respectively, compared with 23.9 % and 39.2 g, respectively, for the Tau Vang. However, there were no significant differences between treatments, and for the mixed and separate diets hen-day production and egg weights were 27.2 % and 41.4 g compared with 26.8 % and 41.4g, respectively. The feed consumption per kg eggs was not significantly different for both treatments and breeds. In addition, CP and ME/kg eggs were not significantly different between breeds, but were between treatments. CP and ME intakes were 602 and 633 g/kg eggs and 50.8 and 52.6 MJ/kg eggs for the Tam Hoang and Tau Vang hens, respectively (P>0.05). For the mixed and separate diets, CP and ME intakes were 681 and 553 g and 49.8 and 53.6 MJ / kg eggs, respectively (P<0.05). The hens from mixed and separate diet can get around 41 % and 44 %f the CP, 42 % and 35 % of the ME intakes (respectively) from the scavenging feed resource.

Key words: choice feeding, egg production, foraging

Introduction

The scavenging system for poultry has existed for a long time in Vietnam, especially in rural areas in the South. The most important characteristic of this system is low feed investment costs, with chickens allowed to scavenge, finding their feed and multiplying by themselves (Le Viet Ly 2000). In rural areas of the Mekong Delta, poultry production is now developing rapidly, especially scavenging chickens. They are maintained with few or no inputs and the main sources of feed are household refuse and pickings from their surroundings. Eggs and chickens can be an important source of animal protein for the family, and eggs can provide a small cash flow, while the birds are reserved for times of celebration or need. These benefits are usually considered to be gratuitous and the scavenging feed resource base is often disregarded (Gunaratne et al 1993).

Binh Yen is a small hamlet in Long Hoa village, located on a large land area about 18 km East of Can Tho, and is occasionally flooded. The total area of the village is 14 square km, and the population 13,380 inhabitants, in about 3000 households. Most of the people live on agriculture. The farming systems in Long Hoa village are generally based on the need to produce food for the family, and on small-scale animal production, with 2 or 3 pigs and 4 – 10 chickens per family. The main source of income is the lemon tree. Poultry production in general, and especially chickens, in Binh Yen Hamlet has not been developed. Farmers raise mainly local chickens, such as the Noi, Tau, Tre and  Ac breeds, and very few Tam Hoang are raised in this area. So, this study was carried out to evaluate an improved breed and an alternative feeding system and introduce these to the farmers.

Objectives of the experiment

· To evaluate the effect of providing dietary ingredients mixed or separately on egg performance and feed conversion under scavenging conditions.

· To compare the responses of two breeds (local and improved) with respect to feed selection, egg performance and feed cost per kg eggs under scavenging conditions.

Materials and methods

Site description

Binh Yen Hamlet, Long Hoa village, Cantho province, is located to the west of Highway 91, in the south of Vietnam. Binh Yen is on an alluvial plain where there is good potential for agriculture. The climate is suitable for raising animals and growing lemon trees. Many development organizations have supported the distribution of improved breeds of cattle, pigs and chickens to the farmers to improve the animal production in the village. For example Heifer International Project has supplied Tau Vang chickens to the local farmers.

Selection and training of the farmers

Firstly a meeting was arranged with Long Hoa People’s committee and the Farmers’ Organization officials. They introduced us to farmers with experience of working with projects and with chickens. After that we selected 6 households in one neighborhood which have relatively large gardens and fields for the hens to scavenge in. The main feed resources from scavenging are by- products of rice after harvesting, insects, grasses and weeds, waste from the pigs, refuse from the family, water spinach etc. In these households the woman play a key role in the livestock farming systems, as they usually stay at home and take care of the family and small flocks of chickens, ducks and a few pigs. A one-day training course on poultry keeping was held, with the objective of training them in aspects of management, such as feeding, following the treatments, collection of eggs, health care, house construction etc.

Experimental design and birds

The experiment was conducted at Binh Yen Hamlet, Long Hoa village, Cantho province, in the rainy season. The experimental design was factorial with 2 factors: the first factor was breed, including local (Tau Vang) and improved (Tam Hoang) hens and the second factor was diet, provided mixed or separately, and including maize, fish and roasted soya bean meal. There were thus four treatments with 6 replications (households) and 5 birds / pen as one experimental unit. The design of the experiment was completely randomized design (CRD). There were included 60 Tam Hoang and 60 Tau Vang females that were transferred to 6 households each with 10 Tam Hoang and 10 Tau Vang. Before transferring to the farms, the hens were vaccinated against Newcastle disease. The hens were confined in the chicken house for the first day for acclimatization and on the second day were released to scavenge on the farm. The hens were allowed to scavenge in the daytime from 07.00h to 17.00h without any feed supplement provided. The feeds were supplied at night time only, with 3 feeders for birds on the separate diet and 1 feeder for those on the mixed diet.. Both diets were supplemented with a vitamin premix.

Experimental diets and management

The experiment included the following 2 treatments applied to each breed (Tau Vang and Tam Hoang). The hens were fed ad – libitum, with maize meal, roasted soya bean meal and fish meal given separately or mixed.

The treatments were:

• Treatment 1: Separate diet including maize meal, fishmeal and roasted soya bean meal supplied separately in 3 feeders, with 2 % bone meal and 5 % oyster shell meal mixed together with the maize meal.
• Treatment 2: Mixed diet including maize meal (70.8%), fish meal (12.0 %) soya bean meal (10.0 %), bone meal (2.0%), oyster meal (5.0 %) and a premix (0.2 %).

The diet was formulated to provide 17.6 % CP (Table 1), which is the recommended CP content for village layers of 16.5 – 17.5 % (Smith 1990) and (calculated) 12.9 MJ/kg ME, and all treatments were supplemented with 0.2 % of a vitamin premix.

The feedstuffs were stored in the grain form and ground each week, as the experiment was carried out in the rainy season, and the feed would quickly get moldy because of the high humidity. The feeds were mixed and transferred to the households each week and the feed residues were also weighed every week.

Housing and environment

The hens were confined at night in divided pens constructed from cast net and bamboo, with floors covered with 20 cm of rice husks for bedding with an average density of 5 hens/ m². Natural light was used in the daytime and artificial light (electric bulbs) at night, with an intensity of 3 W/m ² at floor level during the whole experimental period. The temperature inside the house averaged 25 – 32 ⁰C. At the time of the experiment, the weather was rainy and humidity high, which made it difficult for the hens to scavenge. Water was supplied via plastic tube feeders inside and outside the hen house, and was available throughout the day and night. Feeders used were round plastic basins 20 cm in diameter and 25 cm high, and both feeders and drinker were cleaned and refilled daily in the morning.

The hens were released to the gardens for scavenging each morning at 07.00h, and the feeders were raised so as to be inaccessible. The door of every pen was open for the hens to come in for laying, and the farmers observed the hens every day very carefully and collected the eggs, which were weighed every 3 days.

Diets and feeding

The chemical composition and nutrient values of ingredients and diets are shown in Table 1. The diets were fed for the period from 19 weeks of age to 20 weeks of lay. The feed ingredients were bought and stored in the grain form at the experimental farm, and were transferred to the households every week. The feed ingredients were maize meal, fish meal and oil extracted soya bean meal, and both experiments were carried out at the same time.

Data collection

Data were collected by the women in collaboration with a technical assistant. Feed residues were weighed every week and egg production and egg weight were recorded every day for each pen. Body weight of the hens was recorded at the beginning and the end of the experiment. Economic efficiency parameters were recorded for 20 weeks of lay.

Feed sample analyses and calculations

The mixed diet and feedstuffs for both experiments were analyzed for dry matter (DM), crude protein (N*6.25), crude fibre (CF), ether extract (EE), and ash, Ca and P by standard AOAC methods (AOAC 1990). Analyses of neutral detergent fibre (NDF) of the mixed diet and feedstuffs were also done, following the procedure of Goering and Van Soest (1991). Metabolizable energy (ME) contents of all the diets were calculated from chemical analysis data using the equation of Janssen (1989). Lysine and methionine were analyzed by using a method of high performance liquid chromatography (HPLC).

Birds were weighed, with all 5 hens in each pen as an experimental unit, at the first egg. Daily feed intake was calculated according to the total feed consumption of all the hens in each pen. Feed was offered every day and feed refusals were recorded every week, and the feed consumption calculated. The eggs were collected and weighed every 3 days for each pen to calculate the feed consumption per kg eggs and mean egg weight. Egg production was determined for 20 weeks of lay.

Mortality and behavior

The initial number of birds and number remaining at the end of the experiment were recorded to calculate mortality, and eating behavior and incidence of feather picking and disease were also observed.

Statistical analysis

The data were subjected to analysis of Variance (ANOVA) by using the General Linear Model (GLM) and regression analysis of MINITAB.13 reference Manual Release 12.

Economic analysis

Economic analyses were done by using current prices in Vietnamese Dong (VND) to calculate the differences in total income and total expenses between the two dietary treatments, including feed, and other costs such as for labor, vaccine and medicine were estimated. Finally net profit for each treatment was calculated.

Results

Chemical composition and nutritive value of the feedstuffs and mixed feed

The chemical composition of the ingredients and the mixed diet are shown in Table 1. Maize meal (MM), soya bean meal (SBM), fish meal (FM) and the mixed diet had average dry matter (DM) contents of 85.9, 87.0, 85.7 and 86.3 % respectively. The CP (%) and ME contents (MJ/kg) of the MM, SBM, FM and the mixed diet were 9.0 and 13.78, 40.7 and 11.95, 48.5 and 9.15, and 17.6 and 12.85, respectively.

Feed intake

The daily feed DM, crude protein and ME intakes were significantly different between breeds and diets (P<0.05). They were 49.1 g, 7.8 g and 0.64 MJ, and 38.9 g, 5.9 g and 0.52 MJ for the Tam Hoang and Tau Vang, respectively (Table 2), and were 43.5 g, 7.7 g and 0.55 MJ and 44.5g, 6.12g and 0.60 MJ for the mixed and separate diets (Table 3), respectively.

The proportions of feed ingredients consumed were significantly different for the two diets but not significantly different for breeds. The hens consumed 71.0 % MM, 10.0% SBM and 12.0% FM on the mixed diet, and 79.2 % MM, 8.5 % SBM and 5.3 % FM when feed ingredients were supplied separately. The CP and ME contents were 17.6 %, 12.85 MJ and 14.5 %, 13.1 MJ for the mixed and separate diets, respectively. However, there were no significant differences for breed, and intakes were 75.4 % MM, 9.2 % SBM, 8.4 % FM for the Tam Hoang and 74.8 % MM, 9.3 % SBM and 8.9 % FM for the Tau Vang (P>0.05). The CP and ME contents of the separate diet were 16.0 % and 12.95 MJ, and 16.2 % and 12.93 MJ for the Tam Hoang and Tau Vang, respectively.

Egg performance, mean egg weight and feed consumption per kg eggs

Mean hen – day production of the Tam Hoang and Tau Vang was 30.1 and 23.9 %, respectively (P<0.05) (Table 2). However, there was no significant difference between diets (P>0.05) and production was 27.2 and 26.8 % for the mixed and separate diet, respectively (Table 3).

Mean egg weights were significantly different (P<0.05) for breed, and were 43.5g and 39.2 g for the Tam Hoang and Tau Vang, respectively (Table 2). However, the mean egg weight of the hens on the mixed and separate diets was similar (P>0.05). (Table3).

Feed consumption per kg eggs was not significantly different for breed and diet, and was 3.9 and 4.0 kg feed/kg eggs for the Tam Hoang and Tau Vang, respectively, and 3.9 and 4.0 kg feed/kg eggs for the mixed and separate diets, respectively.

CP and ME/kg eggs were not significantly different for breeds but were different between diets. The Tam Hoang consumed 602 g CP and 50.8 MJ, and the Tau Vang 633 g CP and 52.6 MJ for 1 kg of eggs. Intakes were 681 g CP and 49.8 MJ for the mixed diet, and 553 g CP and, 53.6 MJ per kg eggs for hens on the separate diet (P<0.05).

Feed cost per kg eggs

Feed cost per kg eggs for the Tam Hoang and Tau Vang were 11,161 and 11,654 VND, respectively (NS), and 11,661 and 11,145 VND/kg eggs for the mixed and separate diets, respectively (NS).

Discussion

Feed intake

The feed intake of the Tam Hoang was 21 % higher than of the Tau Vang under scavenging conditions, but in on – station conditions (Nguyen Thi Thuy and Ogle 2003) was only 17 % higher than for the Tau Vang. This seems to indicate that the Tau Vang can scavenge better than the Tam Hoang hens, which is in agreement with Do Viet Minh (1999), who showed that the supplementary feed, CP and ME intakes of an improved breed were 29 to 34 % higher than for a local breed under scavenging conditions. In addition, comparing the feed, CP and ME intakes of the Tam Hoang and Tau Vang raised under scavenging conditions with the same breeds on station indicates that the Tam Hoang and Tau Vang got around 37 % and 40 %, respectively, of their total feed from scavenging. Do Viet Minh (1999) found that scavenging chickens can get around 30 % of their nutrient requirements from scavenging feed resources. The on – farm results show that intakes of CP for the mixed and separate diets were 59 % and 56 %, respectively of the intakes recorded in the on – station experiment (Nguyen Thi Thuy and Ogle ,2003), which implies that around 41 % and 44 % of CP intake was from scavenging, although other factors would also have been involved. Similarly it was calculated that 42 % and 35 % of ME intake on the mixed and separate diets respectively came from scavenging. Thus this implies that birds got relatively more CP than ME from scavenging, and it also indicated that the hens on the separate diet can get more protein than energy from the scavenging feed resource. According to Gunarantne (1998) the nutritional value of the scavenging feed resource varies with the environment. He also concluded that any attempt to intervene with the existing scavenging system by way of supplementation needs careful consideration of the quality and quantity of the scavenging feed resource.

Compared with the NRC (1994) recommendation for feed consumption of Leghorn pullets at 20 weeks of age with live weight at 1.6 kg (around 80 g/day or 14 g crude protein/day, the feed intake data showed that the hens ate less protein from the feed supplied than their requirement, probably because they got significant amounts of protein from scavenging, such as insects, larva, seeds and earthworms from the garden, which were quite abundant in the rainy season. Due to fact that the hens thus could get significant amounts of protein from scavenging so the protein that the hens got from the separate diet was lower than from the mixed feed.

Age at first egg, mortality and weight gain

Age at first egg in the on- farm experiment was lower than in the on - station experiment ((Nguyen Thi Thuy and Ogle 2003), even though the hens were the same age and the experiment carried out at the same time of year. The difference was about 7 days, and was probably because the hens that were transferred to the farms were stressed during transport. The Tam Hoang produced their first egg earlier than the Tau Vang hens, 135 days compared with 142 days, respectively.

The mortality after 20 weeks was higher for the Tau Vang (38.3%) than the Tam Hoang (11.7%), because the Tau Vang were affected by an unknown disease, while the Tam Hoang were not so seriously affected. These values were different from a similar study by Do Viet Minh (1999) in the North of Vietnam, where the mortality of both local and improved breeds of hen was less than 5 %.

The average daily weight gains (ADG) were significantly different between diets and breeds and for the Tau Vang (3.9 g) was higher than for the Tam Hoang (3.0 g), the reason for this probably being that the Tam Hoang produced more and heavier eggs than the Tau Vang, and therefore a higher proportion of the nutrient intake was used for egg production with less available for body tissue synthesis. Also birds on the separate diet had higher ADG than those on the mixed diet, again probably as a result of their lower egg performance and also that the daily feed intake and thus ME intake were higher than on the mixed diet.

Egg performance, mean egg weight and feed consumption per kg eggs

The egg performance and egg weight of the hens kept under scavenging conditions were lower than for the confined hens in the on- station experiment (Nguyen Thi Thuy and Ogle 2003), although the differences were small. But, as was also found on-station, the egg performance and egg weight of the Tam Hoang were always higher than the Tau Vang, because of the genetic difference between the breeds and strains. The improved breed thus has a higher potential for egg production than the local breed, but requires more supplement feed to achieve this potential (Do Viet Minh 1999). For both the mixed and separate diets egg performance and egg weight were similar, which indicates that the total nutrient intakes on the separate diet, including from scavenging, were sufficient to give satisfactory quality and quantity of eggs, and that the hens were able to fairly accurately balance their nutrient intakes to meet their requirement for maintenance and production.

The feed consumption per kg eggs was not significantly different between both breeds and diets. This shows that both the Tam Hoang and Tau Vang have a good ability to scavenge and get a high proportion of the feed they require from the environment. This is in agreement with the study of Do Viet Minh (1999), who concluded that an improved breed was able to scavenge as well as local chickens. In fact, Gunaratne et al. (1993) found that in Sri Lanka scavenging chickens could get over 72 % of their diet from scavenging feed resources and concluded that differences in the proportion of the total feed that comes from scavenging depend on the quantity and quality of the feed resources and the amount supplied. CP intakes/kg eggs were significantly lower for the separate compared with the mixed diet, probably because the hens got significant amounts of protein from scavenging and therefore reduced their intake of the protein feed supplement when it was supplied separately.

Economic analysis

The cost /kg eggs for the two breeds was not different. If the cost of feed per kg eggs is compared with the on station experiment (Nguyen Thi Thuy and Ogle 2003) , the Tam Hoang hens’ feed costs were 73 % and the Tau Vang hens 66 % of the on-station value. This implies that by allowing the birds to scavenge the total feed cost can be reduced by about 27% for the Tam Hoang and 34% for the Tau Vang. The difference between the mixed and separate diets for feed cost per kg eggs is mainly because on the separate diet, the hens consumed less of the expensive soya bean and fish meal and more of the relatively cheap maize meal. However, the difference was non significant.

Conclusions

•  Scavenging hens can get about 37% (Tam Hoang) and 40% (Tau Vang) of their feed from scavenging resources and save 27 – 34% on feed cost per kg eggs compared with on -station conditions.
  
  
•  The hens on the separate diet consumed less protein feeds than those on the mixed diet, probably because they got more protein rich feed when scavenging.
  
  
• The improved Tam Hoang breed has a higher potential for egg production than the local Tau Vang breed and was able to scavenge as well as the local hen.

Acknowlegements

We am grateful to the Swedish International Development Authority (Sida-SAREC) and The Swedish University of Agricultural Sciences (SLU), especially the Department of Animal Nutrition and Management for their support of the study.

We would like to acknowledge the help and hospitality of the members of Long Hoa People’s Committee, especially the head of the animal husbandry group Mr Dat. Many thanks to farmers who were joining in my study: Mrs. Manh, Mrs. Khuon, Mrs. Hoanh, Mr. Muoi Loi, Mrs. Muoi and Mr. Chanh for their help and cooperation.

References

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Gunaratne S P, Chandrasiri A D N, Hemalatha W A P M and Roberts J A 1993 The feed resource based for scavenging village chickens in Sri Lanka. Tropical Animal Health and Production, 26:249-257.

Gunaratne S P 1998 Feeding and nutrition of scavenging village chickens. First INFPD/FAO electronic conference on family Poultry, December 7^th 1998.

Janssen W M A 1989 European Table of Energy Values for poultry Feedstuffs. 3^rd ed. Beekbergen, Netherlands: Spelderholt Center for Poultry Research and Information Services.

Ly LV 2000 A review on poultry production in Vietnam, VN Agricultural publisher, VCN –WEB-site 20, Sep.2000.

Minh D V 1999 Effects of energy and protein supplementation strategy on Production performance of local and improved scavenging hens in North Vietnam, MSc.Thesis, Department of Animal Nutrition and Management, Swedish University of Agricultural Sciences (SLU), Uppsala 1999.

NRC 1994 Nutient requirements of Poultry, ninth revised edition, 1994. 21- 25.

Nguyen Thi Thuy and Ogle B 2003 Evaluation of feed selection on nutrient intake, growth rate and egg performance of confined Tau Vang and Tam Hoang chickens, Master thesis, Department of Animal Nutrition and Management, Swedish University of Agricultural Sciences (SLU), Uppsala, 2003.

Smith A J 1990 Poultry tropical agriculturist series.CTA, Macmillan publishers, London, 47, 55 – 71, 179. Second edition 2001.

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Received 6 April 2016; Accepted 7 April 2016; Published 1 May 2016

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