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The Effect of Breeding System on The Performance of Welfare, Behavior
and Productivity of Laying Hens
Murat Doğu Turkey murat.dogu@tarimorman.gov.tr Mikail Baylan Çukurova University Turkey mikailbaylan@gmail.com Kadriye Kursun Çukurova University Turkey kadriyehatipoglu01n@gmail.com Abstract
In recent years, animal welfare and behavior in livestock farming has become one of the most important topics of current importance. As in other sectors of animal husbandry, animal welfare and behavior is an important issue in the rapidly growing poultry farming sector. Nowadays, the realization of most of the poultry production in conventional cages is considered as a problem in terms of animal welfare and behavior in the world, especially in EU countries. There is a negative impact on the breeding hens in cages. These are stress, health problems and negative behaviors such as inactivity, cage fatigue, foot and leg disorders, cannibalism, feather plucking.
As a result, alternative production systems have been developed in many countries of the world, especially in the European Union. At this point, as given priority animal welfare, enriched cage system in which appropriate environmental conditions provided by different care management practices, organic farming, new cultivation system, such as the free-range system come to the fore.
In this article, animal welfare, behavior and fertility relationships of breeding systems used in poultry are investigated.
Key words: Hen, breeding system, welfare, behavior, egg yield
Yumurtacı Tavuklarda Yetiştirme Sisteminin Refah, Davranış,
Performans ve Verimliliğe Etkisi
Özet
Son yıllarda çiftlik hayvanları yetiştiriciliğinde hayvan refahı ve davranışı giderek önem kazanan güncel konulardan biri haline gelmiştir. Diğer hayvancılık faaliyetlerinde olduğu gibi, sektör olarak hızla büyüyen kanatlı hayvan yetiştiriciliğinde de hayvan refahı ve davranışı önemli bir konudur. Günümüzde yumurta tavukçuluğunun büyük bir kısmının konvansiyonel kafeslerde gerçekleştirilmesi, başta AB ülkeleri olmak üzere dünya genelinde hayvan refahı ve davranışı açısından bir sorun olarak ele alınmaktadır. Kafeste yetiştiriciliğin hayvanlar üzerindeki etkisi hareketsizlik, kafes yorgunluğu, ayak ve bacak bozuklukları, kannibalizm, tüy yolma gibi stres, sağlık sorunları ve olumsuz davranışlar olarak kendisini göstermektedir.
Bunun sonucunda, Avrupa Birliği başta olmak üzere dünyanın birçok ülkesinde, yumurta tavukçuluğunda alternatif üretim sistemleri geliştirilmiştir. Bu noktada, hayvan refahının ön plana alındığı, farklı bakım yönetim uygulamaları ile uygun çevresel koşulların sağlandığı zenginleştirilmiş kafes sistemi, organik yetiştiricilik, serbest dolaşımlı sistem gibi yeni yetiştirme sistemleri ön plana çıkmıştır.
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Bu makalede, yumurta tavukçuluğunda kullanılan yetiştirme sistemlerinin hayvanın refah, davranım ve verim ilişkileri incelenmiştir.
Anahtar Kelimeler: Tavuk, yetiştirme sistemi, refah, davranış, yumurta verimi
INTRODUCTION
While the egg sector has previously been in competition with production quantity and price, it is faced with new demands of consumers on food quality and safety in recent years. The quality of food from animals raised under high welfare standards is also high. For this reason, future animal production strategies; investment planning on the basis of monitoring potential risks to improve animal welfare, develop systems to monitor animal welfare at farm level, and reduce economic losses due to low animal welfare. Today, there are different approaches to scientific assessment of animal welfare. The main reason for this is that the scientific description of animal welfare was initially dealt with by three different theoretical frameworks, which were later understood to be parts of a whole. In this review, each approach developed for scientific welfare assessment is discussed comparatively and based on these approaches, the methods developed to evaluate the welfare of livestock have been summarized (Bozkurt, 2016). In the evaluation of animal welfare by scientific methods, three different theoretical frameworks called biological functioning, emotional state and natural life have been put forward (Bozkurt, 2016). Animal welfare is a broad term that includes the physical and mental state of the animal. Therefore, when the negative emotions are felt intensely, the welfare level is interpreted as low and when the positive emotions are felt intensely, the welfare level is interpreted as high. For this reason, the concept of welfare is put forward as a concept that includes all situations related to the emotions of the animal and especially the absence of suffering. There are two basic questions in determining the welfare level of animals. First, are the animals healthy? Second, can animals show their natural behavior? These questions reveal the physical and mental dimensions of animal welfare (Akbaş, 2013).
Welfare can be defined as providing all animals with conditions that allow them to demonstrate all aspects of their natural behavior (Akbaş ,2013). Research on this subject shows that animals showing their natural behavior move more and have a healthier body structure and therefore lead a longer life. By exhibiting their behavior, animals can easily adapt to changes in their bodies and external environmental conditions (Akbaş, 2013). For this reason, it is one of the basic points in understanding animal behavior, knowing the environment and its effect well. Because fear in animals, stress situations will lead to a decrease in yields, a decrease in marketability of products and a decrease in welfare.
Factors Affecting Behavior In Animals
Genetic
Genetics plays a role in animal behavior, meaning that all behavior is the product of nerve cells and muscles. Genetic information controls the production of proteins that affect chemical reactions in body cells in controlling the development of body tissues. This particular behavior may affect the physiological basis.
Experimental studies have shown that specific genes or groups of genes can affect animal behavior. This does not mean that the behavior is controlled by genes or gene groups. The environment also plays a role in the development and appearance of behavior. Behavior is a combined interaction of genetic and environmental factors.
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Environment
Animals respond to their basic behavior and adapt to the environment in which they live. One of the environmental factors affecting animal behavior is the type of habitat. There are different ways to classify hosting systems Caged and non-caged systems can be divided into two main categories (Anonymous, 2004).
1) Cage systems
1.1) Commercial cages
More chickens are accommodated in the unit area. In the cage system, 2-6% more eggs are taken in the cage system due to the fact that the chickens are less broody, the competition in feed consumption decreases, they are comfortable, the animals afraid can consume feed, the mortality rate is lower and the eating egg habits do not occur. Feed, water, egg collection, fertilizer removal processes in the cage are automated. It is easy to remove non-laying, injured, injured or sick animals as animals have individual control (Anonymous 2019b). In this system, especially parasitic and some bacterial diseases are no longer a risk and the chance of animals to infect each other is reduced. In particular, problems arising from contamination of feed and water are fully prevented. Feathering and cannibalism that occur in animals due to various reasons are eliminated. The eggs obtained are cleaner because they do not come into contact with the litter. It is an important advantage that no mats are needed in the spawning period as in the growing period. If there are variations in the herd due to faults in the breeding system during the growing period, faults arising during the spawning period can be eliminated by hosting the animals separated into different live weights in separate cages. The cage system allows the egg yield controls to be performed in the most secure way (Anonymous 2019b).
In chickens breeding in cages; In the first 4-5 months of the ovulation period, there is a discomfort called cage layer fatigue which prevents animals from standing. Since the metabolic reservoir of calcium used in eggshell formation is bone marrow, osteoperosis develops due to calcium extracted from bone due to high egg yield. Feeding calcium level and source, constant immobilization on inclined wire, or inadequate exercise contribute to the development of this disease by weakening the skeletal system (Anonymous 2019b).
Chicken in cages have more lubrication due to inactivity. Especially fatty liver can cause deaths. Depending on the slope of the cages, the quality and flexibility of the wires used, the characteristics of the egg cradle, the time and number of eggs collected and the number of animals housed in the cage, more broken and cracked eggs can be obtained. Problems in egg collection, manure removal, feed and water distribution, lighting and other breeding techniques affect animals more (Anonymous 2019b).
The chickens are more angry because the roost, perching, padding and other behavior are restricted. Studies on animal welfare and responses to the egg obtained in the cage are usually due to this. The proportion of blood stains in eggs is relatively high in the cage. Since there is a constant social hierarchy in chickens placed in small groups, the problems of welfare related to cannibalism, feather pecking and pinching are undermined. The weekly mortality rate is generally less than 0.1% in well-managed herds raised in commercial cages. In addition, studies on cultivation systems in Scandinavia have reported higher mortality rates in free-flowing and litter systems than in commercial cages (Baykalır and Şimşek, 2014).
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1.2) Enriched cages
Enriched cage systems allow the chickens to exhibit some normal behavior with the equipment it contains. There is an expectation of improvement in socialization and welfare of animals by means of resources such as larger area per chicken, cage perimeter, roost, litter area and need for nail shortening. It has been emphasized that proper placement of perches reduces the risk of injury and injury. Roasted chickens have reduced aggression, do not resist catch and live weight is higher than those who do not use roost.
The unit floor area accommodates fewer animals than conventional cages. Thus, more indoor space per chicken, machinery and equipment costs and consequently an increase in egg production costs. In this system, labor costs are increasing and herd management becomes more difficult. Despite all this, chickens are still closed in the cage (Baykalır ve Şimşek, 2014).
Enriched cages are being investigated extensively. Because it is intended to be the standard system in the European Union in the future. The full efficiency of the enriched cages was found to be as good as that of conventional cages. The spawning rate, which is a determinant of using follicle, is measured between 92% and 95% in different breeding systems and varies between 88% and 99%. In order to explain these differences, differences in nesting management and soil types used in nests were determined. However, chickens can also use nests as shelter that causes hygiene problems. The use of roost overnight in large enriched cages ranges between 65% and 80% and 87%, respectively. During the day this rate is 15% in large cages and 40% in small enriched cages. Other studies have found similar results. However, not only the cage size but also race, nest material and roost are effective in these ratios. The specific problem for enriched cages is the pad or pad area. Mostly the problem is that the area is small and it is covered with plastic material without turning it with wood. Therefore, the litter material interferes with the chicken's mating behavior. In order to ensure proper use of this area for bathing and powder bathing, materials must be checked several times a day. In Germany, the mortality rate in medium and large-scale enriched cages was found to be low. However, the light intensity in the cages has been found to be low and can help explain these results (Anonymous, 2019a).
When the results of different studies are evaluated together, it is shown that hens use additional resources in enriched cages. Additional research is envisaged to improve cage design in terms of matching and sandbox facilities, litter use and management, group size and light intensity in cages. Modern enriched lattices have shown a good improvement compared to conventional lattices. However, they require less space and resources than cage-free systems (Anonymous, 2019a).
2) cage-free systems (Bird Type-Free Circulation-Grid-Backed-Courtyard and Semi-Intensive)
Chickens are protected from wind and natural attackers. Chickens are able to walk around and walk around. They can exhibit natural behaviors such as powder bathing, roosting, flapping, stretching. They can form social groups. If it is free circulation, chickens have the possibility to go out. It is possible to walk in and out. Likewise, it is possible to exhibit and socialize many natural behaviors such as dust bathing, roosting, mating and foraging behavior. While 93-96% of the chickens raised in enriched cages lay eggs in nest boxes, this rate is 89% in bird type systems. In traditional cages there is nest (Anonymous, 2019c). The main shortage of cage-free systems is the risk of feathering and cannibalism. Causes severe injury and pain. Beak cutting is applied in the sector as a remedy but even in this way it decreases welfare. The probable cause of cannibalism is reported as group size. Also beak cutting does not provide a solution for the behavior itself, which only reduces the damage caused by feather pecking. It has been reported that canibalism decreases as the group size increases. Wild ancestors of domestic chickens and old-style courtyard chickens lived in small groups of males and females, allowing individuals
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within this group to know each other's place in the hierarchical system. Since the large group can also cause hair-pulling and cannabis eruptions, the size of the group should be avoided and it is recommended that the maximum number be 100 animals. This can be done either by dividing the flock into portable poultry houses or by dividing the flock into subgroups within the same poultry house. An important problem in cage-free systems is bone fractures. The timing and causes of these fractures are not known, but are probably due to hitting the roost, nest and dust bath. The high yield aspect of the chicken genotypes used is also the most important reason, and in recent years studies have shown that bone resistance may increase with one or two generations of selection without a significant decrease in yield. In order to ensure the welfare of chickens in breeding systems, bone fractures must be prevented. This requires a multi-faceted approach that will involve cultivation, lighting, and other management and administrative aspects. In bird-type and perched systems, it is seen that chickens are grouped in nest boxes and this causes eggs to break and even chickens (Bozkurt, 2009).
Table 1. The predicted behavioral expression level in different breeding systems is
summarized in this way (Lay et al., 2011)
Comparison of Laying Hens Performances in Different Breeding Systems
1- Egg production
According to Anderson (2010), cage and free-circulation rearing systems were found to be 81.9% and 77.7% respectively in terms of egg production of Hy-Line Brown laying hens, Senčić and Butko (2006) found 80.82% and 72.88% respectively. Yakubu et al., (2007) reported that 74% of the cage system and 69% of the pad system. However, Barbosa et al., (2005) and Ergul (2005) did not find any difference between cage and litter systems.
2- Mortality
Mortality rates in the cage-free system are considerably higher than in the cage system (Mostert et al., 1995). According to Anderson (2010), while the mortality rate in the free circulation system is 28.4%, this rate is 8.9% in the cage system. According to Senčić and Butko (2006), it is 6.8% in the free circulation system and 5.5% in the cage system. According to Yakubu
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et al. (2007), the weekly mortality rate was in the litter system (1.1%), whereas this rate was lower in the cage (0.68%).
Table 2. Mortality rates due to canibalism seen in different systems (Fossum et al., 2009)
3- Egg Weight
Egg weight varies depending on the breed of chickens. Castellini et al. (2011), there is a negative correlation between egg weight and egg yield. Other important factors vary depending on the age of the chicken (Rizzi and Chiericato, 2005) and the energy-Hp content of the ration (Krawczyk, 2009).
The egg weight of the chickens raised in the free circulation system is 66.7 g, whereas this rate is 63.4 g in the cage system. (Hidalgo et al., 2008). According to Senčić and Butko (2006), it is 62.4 g in free circulation system and 60.5 g in cage system. In addition, there was no difference in weight in the eggs obtained from the enriched cage and commercial cage system (Guesdon et al., 2004). Similarly, it was observed that there was no difference in the size of the eggs obtained from chickens aged 27-63 weeks grown in the bird cage system with commercial cage system (Tanaka et al., 1992).
Table 3. Performance indicators of laying hens reared in different systems (Anonymous, 2017)
Table 4. Performance indicators of laying hens reared in different systems (Yılmaz Dikmen
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4- Egg quality characteristics
In a study conducted in terms of egg quality characteristics, it was observed that the shell thickness, weight and shell percentage of the eggs in the bird type system were higher.
In another study, shell strength was compared in different breeding systems (commercial cage, enriched cage, bird type and free circulation) and it was found that the eggs in bird type system were more robust and those in free circulation system were weak. In free-circulating systems, the egg color is darker. Eggs obtained from the cage system have higher pH than the free circulation system. It was observed that ovulation outside the nest was higher in chickens raised in cage-free systems, which increased the rate of broken and cracked eggs.
It stated that total fat content, monounsaturated and polyunsaturated fatty acids were higher than the cage system and total cholesterol, vitamin A and E ratios were similar in eggs obtained from free circulation systems. In a study on the trace element content in the egg, they reported that the level of potassium and zinc in the edible part of the egg was high in the commercial system, the magnesium level in the shell was high in the organic system and the zinc level was significantly lower (Baykalır & Şimşek, 2014).
CONCLUSION
As a result; studies on stress physiology, bone resistance and bone fractures, immunology, and mortality in laying hens show that welfare in cage-less systems does not improve as expected. Although the repertoire of chickens is expanding in cage-free systems, the contribution of this situation to welfare is not clear. It is thought that animals are more free because there is more movement in chickens that are generally housed in cage-free systems. This is interpreted as a better prosperity. Although there are significant differences in some behavioral characteristics of laying hens in different hosting systems, there is no definite opinion that these behaviors provide absolute welfare (Lay et al., 2011).
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