broiler feed to day
A Comparison Between Broilers Pastured in a Day Range System and Broilers Raised Intensively in the Gauteng Province, South Africa
Published: June 2, 2008
By: Sebitloane Oneile Urbania, Kanengoni Arnold Tapera, Coetzee Sofia Elizabeth, Botlhoko Tuelo, Palic Dragan and Maphupa Phindile
INTRODUCTION
Poultry production in the industrialized countries has changed significantly during the past 75 years; from pastured flocks of dual-purpose breeds fed on-farm diets (Oden, 1994), to specialized industrial production systems. Today, many health conscious consumers and animal welfare advocates all over the world are demanding farming under natural environments (Trott et al., 2003), and South Africa is no exception to this trend. Alternative poultry production systems, particularly pasture-based production, offers opportunities for producers interested in boosting incomes, diversifying operations, and providing a specialty product for consumers. As farmers have difficulty in entering formal marketing sectors and have a challenge in improving the quality of their product, the promotion of niche products is the best alternative option if they are to succeed. The day range pasture production system is similar to the �Yarding" system, practised by a majority of rural South African farmers, where chickens are shut up in the house at night and allowed to roam about and scratch for food during the day
It has been reported that grass fed meats have cardiac and circulatory benefits, whilst pastured poultry have higher levels of vitamins A, D and E, and conjugated linoleic acids (CLAs) (Trott et al., 2003). The green material of the pasture provides B vitamins as well as carotenes, some of which is turned into vitamin A, while the omega-3 fatty acids in the forage end up in the fat and exposure to sunlight is known to enhance vitamin D metabolism (Salatin, 2005). It is evident that chickens ingest small quantities of pasture, which however contribute as much as 5% to the total feed intake, which is quite significant economically if one considers that feed costs account for 70% of production (Walker & Gordon, 2003). The quality of pasture may therefore affect performance. It was mentioned in a conceptual paper by Ciszuk (1999) that, chickens have a need for protein of animal origin and in a pasture system, they can get that from worms and insects. Whilst in the �Yarding� system farmers use unimproved genotypes, these tend not to be economically viable because of the low growth rate; the new generation of producers have resorted to improved chicken genotypes on pasture because they are readily available not because they are suited to pasture. Modern chicken genotypes used on this system however require more than just pasture and a balanced diet should be provided daily (Fanatico, 2005). In this study two broiler lines were used, Cobb 500 ad Ross 308, largely developed for indoor production (Thear, 2002).
There is a need to improve the current outdoor systems practiced by most developing farmers in South Africa to be more efficient and enable farmers to enter formal markets. Large organisations handle about 80% of the total broiler production, while the informal sector produces the remaining 20% (SAPA, 2000). The concentration of broiler production is situated in Kwa-Zulu Natal and Western Cape followed by Gauteng, the research area with a distribution of about 13.15%. Research and skills are therefore being developed in the Agricultural Research Council to promote an efficient day range production system, enabling the birds to be raised in a more natural way and receiving a balanced commercial diet. This trial was conducted to measure and compare the amount of feed consumed in an indoor deep litter set up and day range pasture system; and also to compare the performance of different genotypes on a pasture feeding system.
MATERIALS AND METHODS
Chickens, Housing and Management
The study was conducted at the Agricultural Research Council (ARC) facilities at Irene, about 20km South of Pretoria. Two lines of broilers commonly used by farmers, (Ross 788 and Cobb 500 broilers) were collected from a local hatchery and put in an environmentally controlled house for the first three to four weeks. Standard management techniques were followed as described by the suppliers of the day-old chicks. All birds were housed in pens with wood shavings and the house temperature was kept as close as possible to 32 �C and decreased periodically until 21 �C was reached at three weeks. Each pen was equipped with a tube feeder and chicken fountain drinker. After four weeks of age they were moved out to a day range pasture system composed of conventional houses in which small openings were made at the bottom to allow them access outdoors to a kikuyu pasture. The kikuyu was harvested at the ARC farm, planted at the experimental site irrigated and maintained by removing weeds and keeping it short for the trial. Dietary treatments consisted of planted pastures combined with free access to commercial feed. Water was also provided ad libitum during the entire trial. Intake of pasture was not measured in this trial.
Experimental design and Measurements
The experiment was designed as a completely randomized block design (CRBD) with four blocks replicated four times. A total of 432 unsexed chickens (216 Ross 788 and 216 Cobb 500 broilers) were randomly allocated according to genotype at the age of three weeks to either: (1) a day range pasture production system, Cobb Outdoor (C-O) and Ross Outdoor (R-O) or (2) an indoor deep litter system; Cobb Indoor (C-I) and Ross Indoor (R-I), resulting in 16 pens of 27 birds per pen. Both systems were given commercial feed ad libitum.
The measurements taken from the birds were weekly group weights between days 28 and 49 and feed intake per pen determined at the time of weighing. At the end of the trial (49 days) all chickens were slaughtered and a four selected from each treatment for meat quality and sensory evaluation.
Data analysis
Performance parameters (body weight, feed intake, feed conversion ratio, mortality, European Production Efficiency Factor) were analysed using the statistical program GenStat (2000). Analysis of variance (ANOVA) was used to test for differences between the 4 treatments. Treatment means were separated using Fishers' protected t-test for least significant difference (LSD) at the 5 % level of significance (Snedecor & Cochran, 1980). The European Production Efficiency Factor (EPEF) was used to compare the different treatments with respect to overall performance.
RESULTS AND DISCUSSION
The responses of pasturing or non pasturing on the performance parameters (body weight, feed intake feed conversion ratio, mortality, European Production Efficiency Factor) on the two broiler lines (Ross 788 and Cobb 500) from days 28 to 49 are presented in Figures 1 to 4 and Table 1. There were no significant differences (P>0.05) between treatments Cobb Outdoor (C-O), Cobb Indoor (C-I), Ross Outdoor (R-O) and Ross Indoor (R-I) in average daily gain (ADG), feed conversion ratio (FCR) and EPEF throughout the growth period. However the two outdoor treatments (R-O, C-O) had a lower bodyweight (P<0.05) than indoor treatments at day 35 (Table 1).This was probably because the outdoor chickens were moved from a completely indoor set-up to a day range system and they had to adapt to the different conditions which could have affected feed consumption and utilization. That they managed to adapt is reflected in the fact that at 49 days there was no difference in bodyweight among the different groups. The bodyweight values of the Cobb and Ross chickens in the study ranged from 1.9 to 2.1 kg at 35 days of age which are comparable to those obtained by Thear (2002) which showed that Cobb as fast growing chickens achieved a weight of 1.8 to 2.3 kg in five to six weeks. Seipel et al. (2002) reported that pastured poultry are more active and therefore have greater energy needs but they can gain more efficiently than the indoor treatments.
Table 1: Means of bodyweight
| Treatments | Day 35 | Day 42 | Day 49 |
| Cobb-outdoor | 2025ab | 2705 | 3335 |
| Cobb-indoor | 2075a | 2727 | 3384 |
| Ross-outdoor | 1959c | 2648 | 3280 |
| Ross-indoor | 1975b | 2718 | 3363 |
| Mean | 2009 | 2700 | 3340 |
| P-value | 0.005 | 0.367 | 0.486 |
| S.E.M.1 | 22.2 | 34.2 | 52.4 |
| L.S.D.2 | 57.5 | 88.7 | 135.9 |
| CV3 | 2.2 | 2.5 | 3.1 |
1 SEM = pooled standard errors of the means
2LSD = least significant difference
3CV% = coefficient of variation
A similar pattern in results was found on feed intake where the Ross outdoor group consumed least feed (P<0.05) compared to the rest of the treatments (Figure 1). This could be attributed to the chickens spending part of the day outdoors but not consuming the pasture, worms and small stones and additionally not feeding frequently on the commercial feed in their pens during the first 10 days. Results for cumulative intake showed differences among all the treatments (P<0.1), where Cobb indoor and Ross indoor treatments had the highest intake (P<0.05). The results by Chisholm et al, (2003) showed that day range chickens consumed 20.9% less feed compared to pasture pens, where chickens are out on pasture the whole time. In addition it was reported that pasture penned chickens consumed pasture and insects that supplemented the diet. However these assertions differ from results found in this study, where Ross outdoor chickens consumed 6% less commercial feed compared to Cobb indoor and made 6% less feed savings than the latter under a day range system. The findings from the present study are more comparable to assertions made by Thompson (1952) that properly managed short good quality pasture can reduce consumption by 5%. Robinson (1948) also commented that keeping chickens on short grass will lead to 10% feed savings or less. Less savings than expected were made possibly because chickens started on the pasture system a week later instead of three weeks and therefore almost fully grown to easily adjust or adapt to the conditions. However the Ross outdoor group had insignificantly better feed conversion ratio (FCR) on the last week of the trial compared to the other treatments (Figure 2). Ross chickens although fast growing and originally bred for indoor production adapted very well to free range conditions. In addition to reducing feed consumption, access to pasture is hypothesized to improve animal health (Chisholm et al., 2003).
The average daily gain of Ross outdoor and Cobb outdoor was insignificantly lower than (P<0.05) the Cobb indoor but higher than the Ross indoor treatment throughout the growth period on the pasture system (Figure 3).This shows that the aforementioned treatment consumed less feed than the rest but efficiently used that feed to gain and achieve almost similar bodyweights (P>0.1) compared to the indoor treatments. Results of the European production efficiency factor are presented on Figure 4. Although there were no differences in the production efficiency factor (PEF) at P>0.1, the Ross outdoor chickens tended to perform better than the rest of the treatments followed by the Cobb outdoor for the whole growth period. This was due to the fact that the aforementioned treatments, Ross and Cobb outdoor had lower but better FCR (2.50) and a higher liveability therefore lower mortality rate than the two indoor treatments. These results are similar but better than from a study done comparing the day range system (2.45, p<0.036) and pasture pen (2.15. p<0.001) to indoor chickens, where an average FCR of 2.77 was found. (Zivnuska C, 2004). Findings similar to these on Cornish Rock broilers compared to an alternative breed raised on pasture showed that the former can achieve slightly superior feed efficiency (2.92) in a day range system.
Figure 1: Means Cumulative Intake of Day range or indoor broilers
Note: F-Test showed significant differences in CI (p<0.05 & p<0.1) between the day range and intensively kept chickens
Figure 2: Means of Feed Conversion Ratio (FCR) for 4 diets from 35 to 49 days
Note: F- test showed no significant differences in FCR (p>0.1) between the treatments
Figure 3: Means of Average Daily Gain (ADG)
* Note: F- Test showed insignificant differences in ADG (p>0.1) between the day range chickens and intensively kept chickens
Figure 4: Means European production efficiency factors of from days 28 to 49
CONCLUSION
It was concluded from the study that Ross 788 chickens adjust very easily and perform better in outdoor conditions compared to the Cobb 500, having a better FCR and the highest production efficiency factor than the indoor treatments. There are savings in keeping chickens in a pasture outdoor system as 6% savings were experienced in this trial as compared to the confinement but pastured based chickens have greater energy needs. Feed efficiency is also enhanced when chickens are raised on pasture. As chickens prefer feeding outdoors when it�s cool, early in the morning and later in the day, restricting their feed intake has a positive effect on feed efficiency. The age of the chickens when introduced to a pastured poultry system has an effect on the performance and feed consumption. Although the intake of pasture was not measured in this study the presumption is they fed on the pasture, insects and small stones that improved digestion and therefore the feed efficiency.
REFERENCES
1. Oden, K: Hons och andra fjaderfan. LTs forlag, Stockholm (In Swedish)), 1994.
2. Trott, D., Chisholm, J., Vogel, M: Nutritional Analysis of poultry reared in controlled pasture conditions versus poultry reared conventionally. 2003.
3. Salatin, J.: Pasturted poultry- The polyface farm model, The Weston A. Price Foundation., 2005.
4. Walker, A. and S. Gordon: Intake of nutrients from pasture by poultry, Proc. Nutrition Society, 2003, 62, 253-256.
5. Ciszuk, P. Pasture broiler combined with cattle and laying hens. The Swedish university of agricultural sciences, Uppsala, 1999.
6. Fanatico, A. Poultry Genetics for Pastured Production. The National Sustainable Agriculture Information service, Attra, 2005.
7. Thear. K.: Free Range poultry- commercial breeds. Broad Leys Publishing. Poultry and Smallholdings. 2002.
8. South African Poultry Association (SAPA): The broiler industry in South Africa. 2000.
9. Genstat for Windows, Oxford: VSN International Release 4.2. 5th Edition. 2000.
10. Snedecor, G.W., and W.G.Cochran: Statistical methods. 7th Edition. Iowa State University Press, 1980.
11. Seipel, M., Chisholm, J., Zivnuska, C., and D. Trott: Feed Efficiency of Pastured Poultry Systems. Truman Sate University, Science Division, 2002.
12. Robinson, L.: Modern Poultry Husbandry. Crosby Lockwood, London 1948.
13. Chisholm, J.L, Trott, D.L, Cox, J.G., Zivnuska, C.E: Feed efficiency of pasture poultry systems. Annual meeting National council on undergraduate research, 2003.
14. Zivnuska, C.. Feed efficiency of Rainbow broilers in pasture poultry systems, Student Research conference, 2004.
Authors: Sebitloane Oneile Urbania1, Kanengoni Arnold Tapera1, Coetzee Sofia Elizabeth1, Botlhoko Tuelo1, Palic Dragan1, and Maphupa Phindile2
1 Agricultural Research Council, Animal Production Institute, Irene, South Africa (SA), P. Bag X2, Irene. 0062, Pretoria
2 Gauteng Provincial Department of Agriculture, Conservation and Environment, SA.
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2 de noviembre de 2011
very interesting study, but more details on morbidity , mortality and use of medication would be more well come to appreciate better the economic benefits of puting birds on pasture beside feed effeciency
regards
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