A COMPARISON OF PRODUCTION AND ECONOMIC PERFORMANCES OF BROIL- ERS RAISED UNDER NATURALLY VENTILATED OPEN-HOUSE AND TUNNEL VEN- TILATED CLOSED-HOUSE SYSTEMS IN SRI LANKA

The objective of this study was to compare production and economic performances of broilers raised under naturally ventilated open house (OH) and tunnel ventilated-closed house (CH) conditions in Sri Lanka. The analysis used production and economic parameters of 130 OH (130 farms) and 88 CH (5 farms) production cycles. Open house farms were selected using proportionate random sampling technique while closed houses were purposively selected.The sum of the Percentages of mortalities and disable birds was significantly higher under OH system compared to that under CH system. The most vulnerable periods for the losses due to mortalities were the first week and from day 29-35 of the growing cycle. The mean length of the growing cycle under OH (38.4 days) was significantly higher than that of CH (34.6 days). OH operators reported a significantly lower number of growing cycles/year (4.4) with a longer clean-out period (44 days) compared to CH (6.9 cycles/year and 18 days, respectively). Production performance indicators such as mortality (3.3%), final live weight (1974 g), feed conversion ratio (1.56), performance efficiency factor (356) of broilers under CH were significantly better than those under OH system (4.5%, 1922 g, 1.94 and 254, respectively). Cost of feeds and day-oldchicks accounted for 74.7 and 23, and 66.6 and 24% of the total variable costs of OH and CH, respectively. Raising of broilers under CH conditions recorded significantly lower total cost (Rs 440), higher net profit (Rs 85.6 bird-1 and unit profitability (Rs 46.8 m-2 day-1) than under OH (Rs 453 and Rs 58.9, Rs 13.2 m-2 day-1, respectively). Production and economic performance indicators and resource utilization efficiencies (temporal and spatial) of broiler production were concluded to be significantly better under CH than OH system. Though production performance parameters of the broiler production, particularly under CH systems were comparable with those of countries having well-developed poultry industries; feed and day-old-chick costs were higher in Sri Lanka.


INTRODUCTION
Reporting 8 kg of annual per capita consumption, poultry meat is the most popular livestock product, across all ethnic and religious communities in Sri Lanka (National Livestock Statistics Bulletin, 2016). Importantly, demand for poultry meat has been predicted to increase at a higher rate than that for other meat types (Henchion et al., 2014). In these circumstances, Sri Lankan poultry industry firstly has to meet the growing demand for poultry products at an affordable price while respecting social values and concerns.Secondly, the industry has meatiness for the broilers kept in CH compared to OH. System-level comparisons on production and economic performance of broilers rearing under Sri Lankan OH and CH conditions are scare. Hence, the present study while comparing the production and economic performances of Sri Lankan OH and CH broiler production systems, discusses the same with those of countries having well-developed broiler industries.

MATERIALS AND METHODS Sampling procedure
Proportionate purposive sampling technique was used to select 130 broiler farms that kept birds under OH conditions. The number of broiler farms that should be selected from each District was determined according to the total number of farms in the respective District (Livestock Statistics Bulletin of Sri Lanka, 2015). Farms within a District were purposively selected considering the following factors.
1). The farm should have been operated at least 2 cycles during the previous year. 2). Required information should be available, reliable and accessible or farmer should be corporative and helpful in collecting data. 3). Proportionate allocation of farms according to the number of small and larger farms. However, due to the above factors (1 and 2), the number of farms selected from small farms was less than that should be. 4). Care was taken to represent both independent and contract farmers. However, contract farmers had to be selected only from 8 Districts where the system was in practice.
Data related to one production cycle of each farm was recorded during January-December 2016. Information related to growth and economic performance was collected using farm records (when available), semi-structured-type questionnaire, and informal discussions with the farmer. All farms obtained day-old chicks (Cobb 500, Hubbard or Indian River) from reputed hatcheries and fed commercial broiler feeds. The commercial brands of day-old 77 are the most popular broiler production systems in Sri Lanka. Open-house system is widely practiced by a vast majority of small and medium scale farmers. In a typical naturally ventilated open house, there are short side walls above which wire nets are fixed to maximize natural ventilation. There may be a moveable curtain which covers the wire-net. When necessary, the curtain is opened to control the inside conditions such as temperature, humidity and air circulation. Birds are reared as flocks of varying sizes on a litter material for manure collection. Open houses may be single or multi-tired. Open house systems are popular in tropical areas where heating is not needed, except during brooding (Spahat, 2014). Despite the popularity of CH, particularly during the last two decades, according to industry information, broilers reared under OH systems accounted for 78% of the production (Hatchery Industry Information; as of May 2018).
Modern broiler strains grow very fast at a remarkably high feed conversion efficiency under specific nutrient and environmental conditions. Provision and maintenance of those environmental conditions are difficult, particularly when a large number of birds are reared. Closed-house system allows more birds are reared in one house under optimum environmental conditions. Closed house is an enclosed environment in which floor is covered with a litter material or carpet to collect manure. The increase of heat, moisture, odorants, ammonia and other noxious gasses inside the cage is prevented by a ventilation system which is often electronically regulated. The ventilation system consists of fans, air inlets, evaporative cooling systemand controllers/thermostats. Sometimes, fogging nozzles are provided, spraying a fine mist of water to lower the air temperature (Lacey et al., 2004).
A Malaysian (Spahat, 2014) and a Philippine (Levy,2017) studies reported better growth performance under CH system than OH system. Disanayaka et al. (2015) reported higher edible meat yield, breast meat percentage, drumstick chicks and feed used by the selected farms cumulatively accounted for 90% and 80% of the market shares in respective sectors in Sri Lanka.
The CH farms were also purposively selected mainly on the accessibility to data/ information. Information about 88 production cycles of 5 commercial CH farm was collected. All farms had 400 ft x 40 ft tunnel ventilated houses with cooling pads.

Determination of growth performance parameters
Following performance evaluation indicators were used 1). Mortality and disable/culled birds % 2

Statistical analysis
Means of continuous variables of OH and CH were compared using two sample t-test on MINITAB Ver 14. Differences were considered when p<0.05.

RESULTS AND DISCUSSION Production performance
A comparison of the production performance of broilers reared under OH and CH conditions are given in Table 2. As expected, the number of birds/cycle under OH conditions was significantly lower than that of CH but varied widely (from 150-28000).

Stocking density and production per unit area
Contrary to the Sri Lankan industry recommendation of 930 cm 2 (1 square foot), it was found that broilers in OH and CH systems received 1305 and 533cm 2 of floor space per bird, respectively. Approximately similar space allowances have been reported by Ekwue et al. (2003) for CH (600 cm 2 /bird) and OH (1000 cm 2 /bird) broiler production systems in Trinidad. Under OH conditions, removal of birds due to mortalities further increased the floor area upto 1730 cm 2 /bird by day 40, while impact of mortality on floor area increase was low (from 533-560cm 2 /bird) under CH conditions. Under CH conditions, commencement of catching as early as day 30 substantially increased the per bird space allowance for remaining birds. This practice helped to secure a high initial stocking density while ensuring sufficient space allowance during the later stages of the growing cycle. Live weight production/m 2 under OH conditions (14 kg) was significantly lower than that of CH (35 kg). However, Committee of the European Union Welfare Directive (2005) recommended a minimum space allowance that corresponds to 33 kg m -2 . Therefore, though Kryeziu et al. (2018) suggested that spacing  and those under OH at lower stocking density (615cm 2 /bird) also caution the use of higher stocking densities under CH. With regard to OH systems as well, it may be suggested that OH system could have been more productive However, adverse impacts of high temperature and poor management conditions on growth, health, welfare and ammonia emission could have been higher had the stoking density was high under OH conditions. Therefore, the provision of a higher space allowance given under OH conditions can be viewed as a compromise between stocking density and the adverse impacts of poor environmental and management conditions. The results of the present study suggest that both OH and CH systems utilizes the available floor area efficiently, by strategically maneuvering the conditions.

Mortalities and disable birds
The sum of the percentages of mortalities and disable birds was significantly (P<0.01) higher under OH system compared to that under CH system. It was observed that the most vulnerable periods for the losses due to mortalities were the first week and from day 29 to 35 of the growing cycle. Indicating the importance of improving management and environmental conditions of OH system, mortality and disable birds during the first week was three times higher under OH compared to CH conditions. Early stage mortalities can be viewed as a loss of a potential income while that of later stages of the production becomes a loss of potential income at a higher cost. Therefore, though mortality values reported herein fall well within those reported in numerous field surveys (Table 3), further reduction of mortality should be a high priority, particularly for OH system.

Growing cycle length
The mean length of the growing cycle under OH (38.4 days; range 32 days to 42 days) was significantly higher than that of CH (34.6 days). Open house operators reported a significantly lower number of growing cycles (4.4) than CH (6.9). Even among relatively more established OH farmers, the number of growing cycles per year was influenced by a number of factors including the availability of chicks and market situations. Consequently, the calculated mean clean-out period of OH system (44 days) was significantly higher than that of the CH (18 days). Longer growing cycles increases the return per bird while shorter cycles permit a higher number of harvests per year. For example, Kleyn (2002) showed that a 38-day growing cycle with an 11-days of clean out period allows an extra cycle per year compared to the practice of 42 day cycles with 14-day intervals.
The traditional broiler management practice in Sri Lanka adopts 42 days growing period and 14 days of clean-out period (Samarakoon and Samarasinghe, 2012), allowing 6.5 cycles per year. Had it operated with 34.6 days of growing cycle and 14 days of clean out period, the CH system could have had a maximum of 7.5 cycles per year. Therefore, as far as temporal utilization of facilities is concerned, CH system is concluded to be operated at closer to its maximum efficiency (92%). Similarly, had OH system operated with 38.4 days of growing cycle with 14 days of clean out period, the system could have operated 6.9 cycles per year. Accordingly, the temporal utilization efficiency of facilities is estimated to be as low as 46.7%.

Feed intake and feed conversion efficiency
Contrary to Al-Marzooqi et al. (2010) who reported 4.7% feed intake reduction for 35 days of growing cycle in OH compared to CH, in the present study feed intake under OH system was 8.9% higher than that of CH conditions. The fact that under OH conditions, birds were kept approximately four more days during which feed intake is high partly explains the above observation. Furthermore, all the CH operations had automated line feeders and adapted a better feeding system management practices. In contrast, apart from 8 farms all other OH operations used bell-shaped feeders and feeding system management was of lesser intensive, leading to more feed wastage. Percentage contributions of the booster, starter, and finisher feeds to the total feed in- takes were not significantly different between two systems (Table 2) and the proportion of each feed in total feed intake (15, 26 and 59%, respectively) were similar to that reported by Dong et al. (2011). Despite the availability of broiler diets for adopting three phas-es feeding program, only 77 and 23% of the CH and OH, respectively practiced three phase feeding regimen. Around 58 and 20% of the farmers skipped either starter or booster diet, respectively.  ditions (34.4days, 1974g, 1.56). FCR values of both production systems distributed normally (Fig 1). Interestingly, Sri Lankan CH system has achieved better FCR values than those reported in many recent studies (Table  3). FCR value under Sri Lankan OH conditions is at least comparable with or sometimes better than those reported elsewhere. However, a potential of achieving better performance even under Sri Lanka OH conditions are indicated by the fact that more than 50% of the Sri Lankan OH farmers had reported a FCR value less than1.9 (Fig 1).

Performance efficiency factor
Compared to FCR, Performance efficiency factor (PEF) better describes farm's overall production performance since a number of performance parameters (feed intake, final live weight, mortality and the length of the growing cycle) are simultaneously taken into account. PEF achieved by Sri Lankan broiler production under CH conditions is comparable with that of the leading broiler producing countries (Table 3). Meanwhile, reflecting inferior performance with respect to all the above parameters, Sri Lankan OH operators reported significantly lower PEF than CH.
The PEF values reported herein for OH is better than that of earlier Sri Lankan study (Samarakoon and Samarasinghe, 2012). Meanwhile, indicating possibilities for further improvements in OH, Tandoğan and Çiçek (2016) and Kryeziu et al.(2018) have reported higher PEF values for Turkish and Kosavo OH sector, respectively.

Economic performance Cost items
Main cost items incurred in broiler production under OH and CH conditions in Sri Lanka are given in Table 4.Variable cost under OH conditions was as high as 97.8% of the total cost while the same was 96.8% for CH. Under OH conditions cost of labour, medications, elec- tricity and loan repayment per bird was significantly lower than those under CH conditions. Many of the OH farms were operated by family labour with minimum hired labour. Therefore, labour cost could have been higher had family labour (which was estimated to be 21.6 labour days/1000 birds) was also considered. Estimation of the loan repayment cost of OH farmers assumed that all farmers had obtained loans on similar repayment conditions. The estimated per bird fixed cost (loan repayment) for CH conditions was 13 times higher than that of OH.
In gross margin analysis, due interest calculated on 10% flat rate of interest, payable in 5 (for OH) and 10 years (for CH), respectively for OH and CH was considered. Due interest in investment for the production of broiler under CH was 6.6 times higher than that of OH. Catching incurred 7.40 Rs /bird under CH whereas it incurred little cost under OH conditions, which included in total labour cost.
Despite the lower cost incurred on the above items, raising of broilers under OH conditions recorded significantly higher total cost per bird, mainly due to the higher feed cost/bird. Irrespective of the production system, feed cost followed by the cost for day-old chick was the largest cost items. Feed and day-old chicks alone accounted for 97.5% and 89.2% of the total cost of production of OH and CH farms, respectively (Fig 3). Irrespective of the level of development of broiler industry, feed cost has been identified the largest cost component (van Horne 2017;Ullah et al., 2017;Rana et al., 2013;Bano et al., 2011). However, compared to Sri Lanka, the share of feed cost in total cost is reported to be lower in countries such as EU, USA, Turkey, Brazil, and Thailand (Table 5).Interestingly, the above countries are among the largest global broiler producers and exporters.
Cost on medications and disinfectants being the third largest cost item, contributed 4.1% to the total cost of production under CH conditions. Therefore, cheaper health and hygiene management interventions that do not adversely affect growth performance are also important, particularly for CH operators. The total cost of production of broilers in OH was significantly higher than in CH. Conversion of the cost of production into eurocents (1Euro=180 Sri Lankan Rupees as of June 2016) showed that Sri Lankan OH and CH systems incurred as high as 131 and 121 eurocents/Kg live weight (Table 5). Feed cost, day -old chick cost and total cost of production in Sri Lanka were substantially higher than those in EU, USA and other countries such as Thailand, Brazil and Turkey with which Sri Lankan broiler industry showed comparable growth performance parameter (Table 3). Therefore, even though the growth performance is comparable with international standards, higher cost of production makes Sri Lankan broiler industry less competitive in export markets. Results of this study highlight the importance of lowering the day-old chick price and most critically the feed cost to make broiler meat more affordable to local consumers and competitive in the international market.

Profitability
In line with the global trend for several decades both in developed (Davis, 2015) and developing countries (Rana et al., 2012), broiler production in Sri Lanka was also found to be profitable (Table 4). Both gross and net profit for the raising of broilers under CH conditions was significantly higher for CH than OH. Per bird net profit under CH was 1.45 times higher than that under OH conditions. Ekwue et al. (2003) reported that profit under CH conditions was two and a half times higher than that of OH. Due to higher investment cost, the difference between gross and net profit was small for CH than OH conditions. Since the analysis considered the same prices per kg of feed for both production systems, the higher financial performance achieved by CH is mainly attributed to the better growth performance. Since the genetic potential of the chicks and the feeds used in both systems are similar, improved performance is mainly a result of better controlled environmental and general management conditions that birds received under CH. Numerous studies (Kaur et al., 2017;Gillespie et al., 2017;Levy, 2017;Farhadi et al., 2016;Liang, et al., 2013), have emphasized that environmental conditions-controlled better housing is crucial in achieving genetic and nutritional potentials. Though provision of improved conditions incurred higher initial investment, production efficiency improvements and larger scale of operations ultimately made CH systems financially more profitable than OH.

CONCLUSION
Growth performance parameters of broilers under CH systems were found to be significantly better than those under OH system. Compared to OH, CH system utilized the available housing spaces more efficiently. Temporal utilization efficiency of resources was also significantly better under CH, compared to OH conditions. Irrespective of the production system, broiler farming was of an economically profitable industry. Despite