Sunday, 7 September 2014

From the egg to the chick


The development of a chick starts not only when the egg is hatched, but already in the Fallopian tube of the hen. More exactly, after the rooster gave his sperm to the hen. The sperm of the rooster and the ovum of the hen merge. Then the nucleus inside the egg yolk serves the chicks as food as does the white of the egg. After laying the egg the development of the chick stands still and will not be resumed until the egg gets hatched.

The course of the egg's production is as follows: The ovum gets out of the ovary and is transported through the Fallopian tube to the cloaca. While it passes the Fallopian tube it is fertilized by the sperm of the rooster and afterwards several layers of the albumen wrap it. Finally, a layer of calcium encloses the albumen.

That's a ready-made egg.
  1. Air chamber
  2. White of the egg
  3. Egg yolk
  4. Eggshell
  5. Chalaza
  6. Germinal disk
Now the egg is ready to get hatched.

1. Day There are not any changes, yet.
3. Day On the egg yolk some blood vessels develop which provide the embryo with nutrients of the white of the egg and the egg yolk.
5. Day On the picture you can see 1) the germinal disk, which moves a little bit and 2) the air chamber. Besides that you can see the blood vessels, which look like threads.
6. Day The blood vessels are getting tighter and look like a cobweb on an X-ray image.
12. Day Within twelve days the embryo develops to look like a ready-made chick, but it only uses one half of the egg, so it will have to grow some more during the remaining nine days within the eggshell. Surprisingly, it is already able to hear.
14. Day On the X-ray image the egg looks dark now and you can only see the bright air chamber on the blunt side of the egg. On the picture you see 1) the fetal membrane which is supplied with blood, 2) the yolk, 3) the blood vessels running from the yolk to the embryo supplying it with nutrients and 4) the breathing membrane.
17. Day After the hatching period of 17 days the chick pierces through the egg membrane, and when its head and beak are in the air chamber it breathes with its lung. Now it perceives the voice of its mother and will remember it for the next few weeks.
19. Day The chicks start to communicate with each other and their mother. So actually they can control when to hatch out and they can delay it for over two hours until all chicks are ready to hatch out. Particularly for wild-living birds this is an advantage, because all the chicks get dry together and they can also leave the nest with their mother at same time. A short time before hatching out (on the 19th or 20th day), the chick pulls the egg yolk through its navel into its stomach, and then the navel locks. So the egg yolk can be used as food for the next 24 hours and the chick does not need any food during these 24 hours.
20. Day Although the brood normally takes 21 days, most of the eggs are pecked on the 20th day. But actually "pecked on" is the wrong expression, because there is not enough room inside the egg to peck. Until a short time before hatching out, the chick's head lies on its breast. Then it lifts its head pressing a hole into the eggshell by means of a thorn located on the beak. By moving inside all the time the whole eggshell cracks and the chick presses against the eggshell. As it lifts the back of the neck it finally opens the lid. Important: The hen does not help the chick at all to get out of the eggshell. That's why you should not help your chicks either.
As mentioned above, the egg yolk gets pulled inside just a short time before hatching out. Afterwards the navel closes. If you help your chicks it can happen, that the navel is not closed yet and you can see that it is bleeding. With bad luck bacteria get inside and threaten the young life of the chick.
21. Day Finally the chick hatches out today.








Proper layer care for consistent supplies of high quality eggs requires knowledge and patience to ensure hens are well housed, fed and watered, and suffer as little stress as possible.

 

There is no secret to successful egg production. Carefully selected hens, well housed, fed and protected against disease reward poultry farmers with a continual supply of high quality, marketable eggs.
Welfare starts from day one when newly-hatched chicks are bought in and taken through the growing phase into laying hens. Then, a careful producer will provide warmth, space, dry litter, recommended vaccines, clean water and appropriate feed, over the next 18 weeks.  
Higher protein (20 per cent) and lower crude fibre (5 per cent) feeds (containing coccidiostat) for chicks up to eight weeks old eventually make way for the lower protein (18 per cent), higher crude fibre (7.2 per cent) feeds for growers at 9-18 weeks. Grower rations are cheaper but producers should watch out for wastage by ensuring feed troughs are not overfilled and tube feeders not fully opened. Farmers can make or buy feed troughs custom designed for spillage reduction.
Failure to take these steps can result in feed wastage levels of up to 25 per cent and transform a potentially profitable egg production enterprise into a loss-making venture even before the first egg is laid. After the growth and development phase, birds are ready for their egg-laying environment at 18 weeks of age.
Successful management of laying flocks hinges on the following factors:
• Housing and light management
• Feed and water management
• Heat stress management

Housing and light management

In the interests of disease management, layers’ quarters should be located at least 100 metres from houses where chicks and growers are raised. Choice of housing is wide and includes intensive (battery cages) and semi-intensive (Californian type battery house, slatted floor housing, deep litter housing and the aviary type house). Producers should be aware that the textbook economic advantages of housing layers in intensive battery houses can be outweighed by loss of production through stress. Where space is not restrictive, producers can opt for the half inside/half outside system that reduces heat stress on birds during the hot season months. Where land is plentiful and predators not a problem, they can use the field ark which is moved onto fresh and clean parts of the pasture every day. In countries with high rainfall, chickens can be kept on pebble yards, which are washed clean daily by rainfall.
Appropriate length of the artificial day used in the house can be manipulated to stimulate egg production. The artificial day may be lengthened in one step or by a series of steps until it reaches 16-18 hours, at which stage maximum number of eggs laid in the shortest possible time should be achieved. More usually and sensibly, the natural lighting of the open type housing traditionally used in the tropics is augmented two hours of artificial light, administered in two 1-hour periods, one in the early hours of the morning (03.30) and the other in the early evening (19.30). Comparative studies show this light regime is economical with electricity and compares favourably in production terms with the conventional programme of continuous lighting (natural and artificial) from 03.30 to 20.30.

Feed and Water Management

Feed and feeding advice for laying hens may seem contradictory. Feed restriction is essential, especially for heavier breeds, if hens are to start laying at the best time and in the best condition. At the same time, birds should never be deprived of feed, and feeders should never be empty i.e. feed should be provided ad lib. 
Hens should start to lay no earlier than 22 weeks old and in the ideal condition (not too fat and not too young). If sexual maturity is attained too early, the length and quality of overall performance will suffer. Eggs will be fewer and smaller with more prolapses towards the end of the laying period. Such birds lack vitality, die early and are more likely to be culled. These problems can be avoided by carefully restricting feed at the right time and in the right way as advised for specific breeds by the farms that sell day-old chicks. Feed restriction should only be used under the following guidelines:
• Use expert advice from the breeding farm relating to the particular breed you have purchased
• Do not start before the birds (at grower stage) are at least 9 weeks old
• Supply feed in a restricted programme based on regular weighing of birds to obtain an accurate live-weight average for the flock:
1. Weigh birds weekly
2. Sample one in 10 of the flock; half from the front of the pen and half from the back
3. Take birds at random using a catching wire
4. Weigh at the same time each week just before feeding
• Provide adequate feeding space so that all birds can feed at the same time
• Make feed change periods gradual. When 10 per cent of egg production has been achieved (at about 23 weeks), the flock should be on layers’ mash
• Stop restrictive feeding if birds become ill or show symptoms of stress; return to feeding ad libitum
The mechanics of restrictive feeding are varied. Farmers can adopt a once-a-day feeding method and, if automated, replenish the troughs at night. Others may prefer to use the ‘miss a day’ method but this carries the risk of increased cannibalism due to the combined effects of boredom and hunger. This is overcome by offering extra rations based on high fibre cereals such as millet or using ‘greens’ that keep the birds ‘happy’ without adding the calories. Feed restriction practices can save the farmer up to 15 per cent in feed costs although potential savings should not enter into the equation when deciding whether or not to embark on this course.  Reducing feed wastage (up to 12 per cent in laying flocks) is a safer and more sensible way of saving money.
Layers’ rations must contain 3-4 per cent calcium, needed for extra strong bones (calcium phosphate) to cope with the stresses and strains of egg production and egg lay, and as a vital ingredient for production of the shell that is mostly of calcium carbonate. Feed lacking in calcium must be boosted with supplementary supplies in the form of grit (e.g. oyster-shell grit). Farmers must ensure that these high calcium levels are present in the diet at least two weeks before laying starts. This timing coincides with the hormonal changes that allow extra calcium to be laid down in the bones, especially the medullary bone tissue from which calcium is mobilised for egg-shell formation.
Poultry require the full range of vitamins, nutrients and amino acids, but Vitamin D in particular has a crucial role in the metabolism of laying hens. Hens lacking in Vitamin D are unable to utilise calcium and phosphorous with serious consequences for bone tissue and egg shells. Ample supplies of cool, clean fresh water are essential for laying hens, especially in the tropics where they will inevitably suffer problems with heat stress. Any lack of water results in loss of production and a higher mortality risk.

Heat stress management

Chickens are better adapted to keeping warm than keeping cool. Normal internal body temperature is 41.3ºC which is just a few degrees centigrade below the temperature at which enzyme inactivation and tissue death begins. The ideal environmental temperature for hens is 12.8ºC, a long way short of the typical daytime temperatures in tropical Asia where heat stress is a huge potential problem. Hens actively maintain their body temperature by:
• Reducing heat absorption by staying in the shade
• Reducing heat production by reducing feed intake and activity
• Increasing heat loss through evaporative cooling
Birds do not have sweat glands and therefore rely on panting (passing air over the moist surfaces of the respiratory tract) to dissipate heat. This causes excessive loss of carbon dioxide, needed to make calcium carbonate in the uterus. The net result is lower egg shell quality with soft shelled eggs a common occurrence. Failure to maintain body temperature leads to a general fall in egg production.
Farmers can help their layers to keep cool by:
• Locating hen houses in the shade
• Providing shade by planting fast growing trees and establishing grass in a 6-metre strip right around the building
• Using open-sided houses orientated east-west to avoid sun shining directly inside
• Constructing wide roof overhangs and placing the roof angle north and south to avoid the direct rays of the sun
• Providing air movement and evaporative cooling



  • Sudah Tepatkah Diagnosa ND, AI atau IB?

|
Salah satu tujuan dari peternakan ayam petelur adalah mendapatkan produksi telur yang optimal. Namun bagaimana bila terdapat gangguan penurunan produksi telur? Tentu hal ini akan menurunkan tingkat produksi. Banyak faktor yang harus dievaluasi terhadap penyebab penurunan produksi telur tersebut diantaranya pakan, kondisi lingkungan, stres, kualitas ayam saat masa starter, grower atau setelah memasuki fase produksi serta penyakit.
Berbicara mengenai penyakit viral yang dapat menurunkan produksi telur, yang paling sering adalah ND (Newcastle disease), IB (infectious bronchitis), AI (avian influenza) dan EDS (egg drop syndrome). Dari hasil pengumpulan data di lapangan sebanyak 2428 kasus penyakit pada ayam layer di tahun 2009, ND, IB dan AI menunjukkan persentase masing-masing 10,63%, 2,84 % dan 1,85 %.
Tabel 1. Ranking penyakit pada ayam layer tahun 2009
Sumber : Data Technical Service Medion, 2009
Berdasarkan pengamatan di lapangan, memang relatif sulit membedakan kasus ND, AI maupun IB. Hal ini dikarenakan adanya gejala klinis maupun perubahan patologi anatomi yang relatif sama antara ketiga penyakit tersebut. Terlebih lagi kita dibingungkan dengan isu penyakit tertentu misalnya AI sehingga persepsi diagnosa kita mengarah ke AI meski bisa saja kasus yang terjadi adalah ND. Agar tidak terjadi kesalahan dalam mendiagnosa ND, AI maupun IB maka perlu dipelajari gejala-gejala penyakitnya secara detail.
Dalam mendiagnosa penyakit maka yang perlu dilakukan adalah mengumpulkan data-data berupa anamnesa, gejala klinis, serta perubahan patologi anatomi (bedah bangkai) dan juga uji laboratorium jika diperlukan.
1.   Anamnesa
Keterangan dari peternak merupakan informasi penting untuk mengarahkan diagnosa. Keterangan yang diperlukan antara lain umur dan tipe ayam, persentase kematian, lamanya penularan penyakit, sejarah vaksinasinya, kasus penyakit pada periode pemeliharaan sebelumnya, dll.
Pengamatan terhadap pola penularan penyakit dapat memberikan gambaran diagnosa. Menurut Tabbu (2002), pada infeksi alami leleran hidung yang mengandung virus ND akan dibebaskan dari ayam sakit sebagai akibat replikasi virus tersebut di dalam saluran pernapasan. Virus ND yang diekskresikan (dikeluarkan,red) bersama feses akan menyebar dengan lambat, terutama jika ayam tidak kontak secara langsung dengan ayam sakit. Masa inkubasi (waktu mulai bibit penyakit menginfeksi sampai munculnya gejala klinis) berkisar antara 2-15 hari dan rata-rata 5-6 hari.
Virus AI ditularkan dengan kontak langsung dari unggas peka melalui leleran hidung, konjungtiva dan feses. Penularan juga dapat terjadi secara tidak langsung seperti melalui debu, ransum, air minum maupun peralatan kandang yang terkontaminasi oleh virus AI. Masa inkubasi sangat cepat yaitu berkisar beberapa jam sampai 3 hari.
Masa inkubasi pada kasus IB hampir mirip dengan AI yaitu berkisar antara 18-36 jam. Penularan dapat terjadi melalui leleran hidung ataupun feses ayam yang sakit.
Penyakit ND, AI maupun IB dapat menunjukkan angka kematian tinggi. Pada kasus ND dan AI, dapat menyebabkan kematian hingga 90–100 % . Terlebih lagi jika ayam belum pernah divaksin AI, maka kematian drastis dan bahkan mencapai 100 % dalam waktu 3 hari. Sedangkan anak ayam yang terserang IB, tingkat kematian berkisar 0-40%, berbeda dengan ayam fase produksi yang mencapai 25%. Namun, banyaknya tingkat kematian tersebut juga dipengaruhi oleh jumlah maupun tingkat keganasan virus tantang yang ada di lapangan.

2.   Gejala Klinis
     a.  Penurunan produksi telur
Permasalahan yang paling terlihat nyata pada peternakan ayam layer yang sudah memasuki masa produksi adalah terjadinya penurunan produksi telur. Namun untuk mendiagnosa tidak hanya semata-mata berdasarkan penurunan produksi telur. Tetapi juga dari segi penurunan kualitas telur . Ketiga penyakit viral tersebut dapat menunjukkan warna telur yang pucat hingga berwarna putih dan terkadang kerabangnya tipis maupun lembek.
                                                                                                                (a)                                                 (b)
Kerabang telur pucat (a); putih telur encer spesifik penyakit IB (b)
(Sumber : www.theranger.co.uk & Dok. Medion)
Serangan penyakit IB mampu menurunkan produksi telur hingga 60% dalam waktu 6-7 minggu. Penurunan produksi telur selalu diikuti dengan penurunan kualitas telur seperti gangguan bentuk telur, kerabang lembek dan cairan albumin (putih telur) lebih encer daripada biasanya. Putih telur yang encer merupakan ciri spesifik dari penyakit IB. Selain putih telur encer, terkadang juga ditemukan darah di dalam albumin atau kuning telur (blood spot). Sedangkan penurunan produksi pada AI dapat mencapai 80% dan ND bisa mencapai 100% dalam waktu cepat.

     b.  Feses (kotoran ayam)
Feses juga bisa memberikan rambu untuk mengarahkan penyakit, namun tidak terlalu spesifik. Pada kasus AI, warna feses cenderung hijau pupus yang kadang disertai darah dan lendir yang dominan sehingga bentuknya seperti pasta dan menempel pada pantat. ND cenderung menunjukkan manifestasi feses berwarna hijau lumut campur keputihan dan biasanya lebih encer jika dibandingkan pada kasus AI. Tetapi yang perlu dicatat, jika peternak tidak biasa mengamati perubahan feses tersebut maka perlu dilakukan pemeriksaan lebih lanjut karena pengamatan feses ini tidak bisa dijadikan patokan utama untuk menyimpulkan diagnosa.

                                                                  (a)                                             (b)
Feses berwarna hijau dan bercampur lendir pada kasus AI (a);
feses berwarna hijau campur warna keputihan dan cenderung encer pada kasus ND (b)
(Sumber : Tony Unandar)
     c.  Gejala tortikolis (leher terpuntir)
Gejala tortikolis selama ini identik dengan diagnosa ND sehingga penyakit ND sering disebut dengan istilah “tetelo”. Namun jika ditelaah lebih lanjut, tidak selamanya gejala tersebut spesifik mencirikan ND. Pada beberapa kasus AI dapat ditemukan pula kejadian tortikolis meskipun presentasinya sedikit. Gejala tortikolis ini juga spesifik pada serangan penyakit AE (Avian Enchephalomyelitis) dan SMS (Spiking Mortality Syndrome) namun sering disertai dengan tremor (gemetar,red) seluruh tubuh.

     d.  Gejala pernapasan
Ketiga virus penyebab penyakit ND, AI dan IB selain menyerang saluran reproduksi, juga menyerang saluran pernapasan Manifestasi yang nampak adalah adanya gangguan pernapasan seperti ngorok, bersin, batuk, megap-megap, kesulitan bernapas maupun keluarnya leleran lendir dari hidung ataupun mulut.

3.   Perubahan Patologi Anatomi
     a.  Saluran pernapasan
Pengamatan perubahan patologi anatomi pada saluran pernapasan, akan terlihat lebih spesifik pada kasus IB dimana peradangan terjadi pada bronchus (percabangan trachea,red). Pada kasus ND terkadang menunjukkan gejala pernapasan namun tidak terlalu spesifik. Sedangkan AI, biasanya ditemukan ingus/lendir kental dalam jumlah banyak pada saluran pernapasan maupun rongga mulut sehingga ayam mengalami kesulitan dalam mengambil oksigen.
Pneumonia (radang paru-paru,red) menjadi ciri spesifik AI. Pneumonia ini mengakibatkan kurangnya kadar oksigen di dalam sistem sirkulasi darah sehingga gejala yang muncul jengger, muka dan pial akan tampak berwarna kebiru-biruan. Peradangan yang terjadi pada kasus AI lebih bersifat echimosa yaitu tipe perdarahan dalam bentuk bintik-bintik merah dengan ukuran yang tidak sama besar.
                                                                        (a)                                      (b)
                                                                      (c)                                         (d)
Lendir berlebihan pada saluran pernapasan (a); peradangan laryng (b);
trachea (c); paru-paru (d) pada kasus AI
(Sumber : Dok. Medion & Tony Unandar)
      b. Lemak jantung
ND dan AI sering menunjukkan perubahan berupa adanya perdarahan pada lemak jantung. Sedangkan pada IB tidak akan menunjukkan gejala perubahan ini. Jika dilihat dari peradangan di lemak jantung, tidak ada yang spesifik untuk membedakan kedua jenis penyakit tersebut.

      c. Proventrikulus
Proventrikulus menghasilkan asam klorida (HCl) yang berperan dalam membantu proses pencernaan sehingga kondisi proventrikulus menjadi asam. Pada kasus AI, perdarahan lebih terjadi di proventrikulus bagian depan dan cenderung pada perbatasan proventrikulus dan oesophagus (kerongkongan,red). Hal ini dikarenakan virus AI memiliki sifat tidak tahan asam. Jika ND yang menyerang maka besar kemungkinan peradangan terjadi pada puncak/bintik-bintik proventrikulus, namun ketika serangan sudah parah maka peradangan bisa menyeluruh pada proventrikulus.
                                   (a)                                         (b)
Peradangan pada perbatasan proventrikulus & esophagus kasus AI (a),
puncak proventrikulus kasus ND (b)
(Sumber : Dok. Medion)

      d. Usus
Usus terbagi menjadi usus halus, usus besar dan usus buntu. Usus tersebut merupakan organ pencernaan dimana bakteri patogen dan non patogen dapat tumbuh dengan mudah. Hampir semua jenis penyakit pada ayam menunjukkan adanya peradangan pada usus baik ringan maupun berat. Bahkan pada ayam yang tidak mau makan atau ukuran pakan yang terlalu besar juga dapat menyebabkan peradangan di usus.
Ciri spesifik ND adalah adanya peradangan pada peyer patches (lempeng peyer,red) yang disertai peradangan pada proventrikulus. Terjadinya perdarahan di usus memang agak relatif sulit dibedakan antara ND, AI ataupun dengan penyakit bakterial.
(a)
(b)
Peradangan pada usus (a); peradangan pada lempeng peyer kasus ND (b)
(Sumber : Dok. Medion)

      e. Organ reproduksi
Adanya penurunan produksi telur erat kaitannya dengan organ reproduksi. Terjadinya gangguan pada salah satu bagian organ maka manifestasinya berbeda pula.
Organ reproduksi ayam betina
(Sumber : Dok. Medion)
Keterangan gambar :
01. Ovarium 
02. Infundibulum 
03. Magnum 
04. Istmus
05. Uterus
06. Vagina
07. Oviduct kanan
08. Ureter
09. Kloaka

Gejala putih telur encer pada IB memang diakibatkan oleh kerusakan pada oviduct (saluran telur) di bagian magnum. Magnum merupakan tempat dimana terjadi proses pembentukan albumin (putih telur, red).
Berbeda halnya dengan ND dan AI, dimana virus tersebut menyerang pada bagian ovarium/ calon kuning telur. Terkadang kuning telur mengalami pengecilan ukuran, selaput telur membengkak serta mengalami perdarahan.
                            (a)                                                                  (b)
Peradangan pada ovarium kasus AI (a); cystic oviduct kasus IB (b)
(Sumber : Dok. Medion)
Apabila organ reproduksi tersebut parah maka manifestasinya adalah penurunan produksi telur yang drastis serta relatif sulit untuk disembuhkan kembali. Pada beberapa tahun terakhir ini, manifestasi IB sering berupa cystic oviduct dimana terdapat penimbunan cairan bening dengan volume hingga 1,5 liter di oviduct.
Dari anamnesa, gejala klinis maupun perubahan patologi anatomi yang jelas dan spesifik, kita dapat menyimpulkan diagnosa penyakit yang sedang menyerang. Sehingga kita sudah dapat mengambil langkah yang tepat. Sebagai contoh, apabila data-data yang dikumpulkan mengarah ke kasus ND maka kita dapat segera melakukan revaksinasi darurat dengan  ND Clone 45.Jika ayam terindikasi IB maka dapat segera dilakukan revaksinasi menggunakan IB H-120. Namun yang perlu diingat, revaksinasi sebaiknya dilakukan pada ayam-ayam yang terlihat masih agak sehat. Sedangkan pada ayam-ayam yang sudah parah sebaiknya diafkir. Setelah dilakukan revaksinasi darurat, perlu diberikan vitamin seperti anti Stress atau Fortevit guna meningkatkan stamina ayam serta membantu pemulihan kesehatan. Yang tidak boleh terlupakan adalah tetap memperketat biosekuriti serta mengurangi faktor penyebab stres pada ayam. 
 

Pada beberapa kasus di lapangan, meskipun sudah dilakukan pencarian data meliputi riwayat kasus, gejala klinis, perubahan patologi anatomi, namun belum ada yang spesifik untuk mengindikasikan suatu penyakit. Dalam menghadapi kondisi yang demikian, maka diperlukan data pendukung berupa uji serologi. Uji yang dilakukan berupa HI Test (Haemagglutination Inhibition Test) atau ELISA (Enzym Linked Immunosorbent Assay). SampeI yang digunakan untuk uji serologi ini adalah serum sebanyak 0,5 % dari total populasi atau minimal 15-20 sampel tiap flok. Tujuan uji HI test atau ELISA tersebut adalah untuk mengetahui gambaran titer antibodi dalam tubuh ayam sehingga terdapat kemungkinan gambaran titer yang terbaca merupakan indikasi adanya virus tantang di lapangan.
Dalam beberapa kasus di ayam broiler, ayam tidak menunjukkan gejala klinis maupun perubahan patologi anatomi namun dalam 3 hari kematian mencapai 90%. Ketika dilakukan uji serologi HI test terhadap AI, semua sampel tidak menunjukkan adanya titer antibodi dan ayam belum pernah divaksin. Dalam menyimpulkan data-data seperti ini, peternak pun terkadang masih ragu apakah diagnosa tersebut AI. Namun jika dilihat dari tingkat kematian, diagnosa bisa mengarah ke AI.
Untuk mengetahui secara pasti virus penyebab sakit tersebut, dapat dilakukan uji PCR (Polymerase Chain Reaction) dimana pada uji ini berfungsi untuk mendeteksi ada tidaknya virus di dalam tubuh ayam. Uji PCR menggunakan sampel berupa organ ayam yang mengalami perubahan patologi anatomi, swab (usap,red) trachea atau kloaka. Sampel yang akan diuji tidak boleh dicuci dengan menggunakan desinfektan karena virus akan mati. Hasil dari uji PCR ini dapat digunakan sebagai pedoman dalam perbaikan manajemen dan kesehatan ayam pada pemeliharaan berikutnya.

Mengapa Harus Tepat Diagnosa?
Terkadang banyak peternak mengeluhkan karena meskipun sudah diobati ataupun dilakukan revaksinasi darurat, namun produksi tidak kunjung pulih padahal juga sudah didukung dengan biosekuriti yang ketat. Hal tersebut bisa saja terjadi karena adanya kesalahan diagnosa penyakit.
Ketika gejala-gejala adanya infeksi penyakit ditangani sedini mungkin maka tidak menutup kemungkinan produksi dapat pulih kembali. Pada beberapa kasus ND proses recovery (pemulihan,red) produksi telur memerlukan waktu yang relatif lebih singkat dibandingkan proses recovery pada kasus IB meskipun produksi tidak seoptimal seperti sebelumnya.
Selain untuk mendapatkan penanganan yang tepat, manfaat lain dari diagnosa yang benar ini dapat dijadikan sebagai pembelajaran untuk pemeliharaan berikutnya. Dengan demikian perlu dilakukan antisipasi sbb :
  • Evaluasi kembali program vaksinasi yang sudah ada. Jika belum tepat maka perlu dilakukan penyusunan program vaksinasi sesuai dengan kondisi di peternakan tersebut. Minimal dilakukan vaksinasi pada 3-4 minggu untuk vaksin inaktif atau 2-3 minggu vaksin aktif sebelum penyakit sering terjadi sehingga ketika terdapat serangan dari virus lapangan, ayam telah memiliki antibodi yang cukup untuk melawan infeksi lapangan.
  • Pada masa produksi, perlu dilakukan monitoring / pemeriksaan titer antibodi secara rutin setiap bulan terhadap penyakit yang sering menyebabkan penurunan produksi telur terutama ND dan AI untuk mengetahui gambaran titer antibodi dalam tubuh sehingga bisa menentukan jadwal revaksinasi dengan tepat. 





    Poultry farming

    From Wikipedia, the free encyclopedia
    Maler der Grabkammer des Sennudem 001.jpg
    Agriculture
    General
    History
    Types
    Categories
    Portal icon Agriculture / Agronomy portal
    Poultry farming is the raising of domesticated birds such as chickens, turkeys, ducks, and geese, for the purpose of farming meat or eggs for food. Poultry are farmed in great numbers with chickens being the most numerous. More than 50 billion chickens are raised annually as a source of food, for both their meat and their eggs.[1] Chickens raised for eggs are usually called layers while chickens raised for meat are often called broilers.[1] In the US, the national organization overseeing poultry production is the Food and Drug Administration (FDA). In the UK, the national organization is the Department for Environment, Food and Rural Affairs (Defra).

    Intensive and alternative poultry farming

    According to the World Watch Institute, 74 percent of the world's poultry meat, and 68 percent of eggs are produced in ways that are described as 'intensive'.[2] One alternative to intensive poultry farming is free-range farming using lower stocking densities. all seasons at a lower cost than free-range production.[citation needed] Poultry producers routinely use nationally approved medications, such as antibiotics, in feed or drinking water, to treat disease or to prevent disease outbreaks.[citation needed] Some FDA-approved medications are also approved for improved feed utilization.[citation needed]

    Egg-laying chickens - husbandry systems

    Commercial hens usually begin laying eggs at 16–20 weeks of age, although production gradually declines soon after from approximately 25 weeks of age.[3] This means that in many countries, by approximately 72 weeks of age, flocks are considered economically unviable and are slaughtered after approximately 12 months of egg production,[4] although chickens will naturally live for 6 or more years. In some countries, hens are force moulted to re-invigorate egg-laying.
    Environmental conditions are often automatically controlled in egg-laying systems. For example, the duration of the light phase is initially increased to prompt the beginning of egg-laying at 16–20 weeks of age and then mimics summer daylength which stimulates the hens to continue laying all year round; normally, egg production occurs only in the warmer months. Some commercial breeds of hen can produce over 300 eggs a year.[citation needed]

    Free-range


    Commercial free range hens

    Free range chickens being fed outdoors
    Main article: Free range
    Free-range poultry farming allows chickens to roam freely for a period of the day, although they are usually confined in sheds at night to protect them from predators or kept indoors if the weather is particularly bad. In the UK, the Department for Environment, Food and Rural Affairs (Defra) states that a free-range chicken must have day-time access to open-air runs during at least half of its life. Unlike in the United States, this definition also applies to free-range egg laying hens. The European Union regulates marketing standards for egg farming which specifies a minimum condition for free-range eggs that "hens have continuous daytime access to open-air runs, except in the case of temporary restrictions imposed by veterinary authorities".[5] The RSPCA "Welfare standards for laying hens and pullets" indicates that the stocking rate must not exceed 1,000 birds per hectare (10 m2 per hen) of range available and a minimum area of overhead shade/shelter of 8 m2 per 1,000 hens must be provided.
    Free-range farming of egg-laying hens is increasing its share of the market. Defra figures indicate that 45% of eggs produced in the UK throughout 2010 were free-range, 5% were produced in barn systems and 50% from cages. This compares with 41% being free-range in 2009.[6]
    Suitable land requires adequate drainage to minimise worms and coccidial oocysts, suitable protection from prevailing winds, good ventilation, access and protection from predators. Excess heat, cold or damp can have a harmful effect on the animals and their productivity.[citation needed] Free-range farmers have less control than farmers using cages in what food their chickens eat, which can lead to unreliable productivity, though supplementary feeding reduces this uncertainty.[citation needed] In some farms, the manure from free-range poultry can be used to benefit crops.[7]
    The benefits of free-range poultry farming for laying hens include opportunities for natural behaviours such as pecking, scratching, foraging and exercise outdoors.[8]
    Both intensive and free-range farming have animal welfare concerns. Cannibalism, feather pecking and vent pecking can be common with some farmers using beak trimming as a preventative measure, although reducing stocking rates would eliminate these problems.[9] Diseases can be common and the animals are vulnerable to predators.[9] Barn systems have been found to have the worst bird welfare.[9] In South-East Asia, a lack of disease control in free range farming has been associated with outbreaks of Avian influenza.[10]

    Organic

    In organic egg-laying systems, chickens are also free-range. Organic systems are based upon restrictions on the routine use of synthetic yolk colourants, in-feed or in-water medications, other food additives and synthetic amino acids, and a lower stocking density and smaller group sizes.[citation needed] The Soil Association standards[11] used to certify organic flocks in the UK, indicate a maximum outdoors stocking density of 1,000 birds per hectare and a maximum of 2,000 hens in each poultry house. In the UK, organic laying hens are not routinely beak-trimmed.

    Yarding

    Main article: Yarding
    While often confused with free-range farming, yarding is actually a separate method of poultry culture by which chickens and cows are raised together. The distinction is that free-range poultry are either totally unfenced, or the fence is so distant that it has little influence on their freedom of movement. Yarding is common technique used by small farms in the Northeastern US. The birds are released daily from hutches or coops. The hens usually lay eggs either on the floor of the coop or in baskets if provided by the farmer. This husbandry technique can be complicated if used with roosters, mostly because of aggressive behaviour.

    Battery cage


    Hens in a battery cage system. Light intensity is usually lower, e.g. 10 lux.[12]

    Egg-laying chicken 5 days out of a battery cage. Note the damaged feathers typical of hens in this (and other) housing systems.[9]
    Main article: Battery cage
    The majority of hens in many countries are reared in battery cages, although the European Union Council Directive 1999/74/EC[13] has banned the conventional battery cage in EU states from January 2012. These are small cages, usually made of metal in modern systems, housing 3 to 8 hens. The walls are made of either solid metal or mesh, and the floor is sloped wire mesh to allow the faeces to drop through and eggs to roll onto an egg-collecting conveyor belt. Water is usually provided by overhead nipple systems, and food in a trough along the front of the cage replenished at regular intervals by a mechanical chain.
    The cages are arranged in long rows as multiple tiers, often with cages back-to-back (hence the term 'battery cage'). Within a single shed, there may be several floors containing battery cages meaning that a single shed may contain many tens of thousands of hens. Light intensity is often kept low (e.g. 10 lux) to reduce feather pecking and vent pecking. Benefits of battery cages include easier care for the birds, floor eggs which are expensive to collect are eliminated, eggs are cleaner, capture at the end of lay is expedited, generally less feed is required to produce eggs, broodiness is eliminated, more hens may be housed in a given house floor space, internal parasites are more easily treated, and labor requirements are generally much reduced.
    In farms using cages for egg production, there are more birds per unit area; this allows for greater productivity and lower food costs.[14] Floor space ranges upwards from 300 cm2 per hen. EU standards in 2003 called for at least 550 cm2 per hen.[15] In the US, the current recommendation by the United Egg Producers is 67 to 86 in2 (430 to 560 cm2) per bird.[16] The space available to battery hens has often been described as less than the size of a piece of A4 paper.[17] Animal welfare scientists have been critical of battery cages because they do not provide hens with sufficient space to stand, walk, flap their wings, perch, or make a nest, and it is widely considered that hens suffer through boredom and frustration through being unable to perform these behaviours.[18] This can lead to a wide range of abnormal behaviours, some of which are injurious to the hens or their cagemates.

    Furnished cage

    Main article: Furnished cages
    In 1999, the European Union Council Directive 1999/74/EC[13] banned conventional battery cages for laying hens throughout the European Union from January 1, 2012; they were banned previously in other countries including Switzerland. In response to these bans, development of prototype commercial furnished cage systems began in the 1980s. Furnished cages, sometimes called 'enriched' or 'modified' cages, are cages for egg laying hens which have been designed to overcome some of the welfare concerns of battery cages whilst retaining their economic and husbandry advantages, and also provide some of the welfare advantages of non-cage systems. Many design features of furnished cages have been incorporated because research in animal welfare science has shown them to be of benefit to the hens. In the UK, the Defra "Code for the Welfare of Laying Hens"[19] states furnished cages should provide at least 750 cm2 of cage area per hen, 600 cm2 of which should be usable; the height of the cage other than that above the usable area should be at least 20 cm at every point and no cage should have a total area that is less than 2000 cm2. In addition, furnished cages should provide a nest, litter such that pecking and scratching are possible, appropriate perches allowing at least 15 cm per hen, a claw-shortening device, and a feed trough which may be used without restriction providing 12 cm per hen.
    Modern egg laying breeds often suffer from osteoporosis which results in the chicken's skeletal system being weakened. During egg production, large amounts of calcium are transferred from bones to create egg-shell. Although dietary calcium levels are adequate, absorption of dietary calcium is not always sufficient, given the intensity of production, to fully replenish bone calcium. This can lead to increases in bone breakages, particularly when the hens are being removed from cages at the end of laying.

    Meat-producing chickens - husbandry systems

    Main article: Broiler industry

    Broilers in a production house

    Indoor broilers

    Meat chickens, commonly called broilers, are floor-raised on litter such as wood shavings, peanut shells, and rice hulls, indoors in climate-controlled housing. Under modern farming methods, meat chickens reared indoors reach slaughter weight at 5 to 9 weeks of age. The first week of chickens life they can grow 300 percent of their body size, a nine week old chicken can average over 9 pounds in body weight. At nine weeks a hen will average around 7 pounds and a rooster will weigh around 12 pounds, having a nine pound average.
    Broilers are not raised in cages. They are raised in large, open structures known as grow out houses. A farmer receives the birds from the hatchery at one day old. A grow out consist of 5 to 9 weeks according on how big the kill plant wants the chickens to be. These houses are equipped with mechanical systems to deliver feed and water to the birds. They have ventilation systems and heaters that function as needed. The floor of the house is covered with bedding material consisting of wood chips, rice hulls, or peanut shells. In some cases they can be grown over dry litter or compost. Because dry bedding helps maintain flock health, most growout houses have enclosed watering systems (“nipple drinkers”) which reduce spillage.[20]
    Keeping birds inside a house protects them from predators such as hawks and foxes. Some houses are equipped with curtain walls, which can be rolled up in good weather to admit natural light and fresh air. Most growout houses built in recent years feature “tunnel ventilation,” in which a bank of fans draws fresh air through the house.[20]
    Traditionally, a flock of broilers consist of about 20,000 birds in a growout house that measures 400/500 feet long and 40/50 feet wide, thus providing about eight-tenths of a square foot per bird. The Council for Agricultural Science and Technology (CAST) states that the minimum space is one-half square foot per bird. More modern houses are often larger and contain more birds, but the floor space allotment still meets the needs of the birds. The larger the bird is grown the less chickens are put in each house, to give the bigger bird more space per square foot.[20]
    Because broilers are relatively young and have not reached sexual maturity, they exhibit very little aggressive conduct.[20]
    Chicken feed consists primarily of corn and soybean meal with the addition of essential vitamins and minerals. No hormones or steroids are allowed in raising chickens.[20][21]

    Issues with indoor husbandry

    In intensive broiler sheds, the air can become highly polluted with ammonia from the droppings. In this case a farmer must run more fans to bring in more clean fresh air. If not this can damage the chickens’ eyes and respiratory systems and can cause painful burns on their legs (called hock burns) and blisters on their feet. Broilers bred for fast growth have a high rate of leg deformities because the large breast muscles causes distortions of the developing legs and pelvis, and the birds cannot support their increased body weight. In cases where the chickens become crippled and can't walk farmers have to go in and pull them out. Because they cannot move easily, the chickens are not able to adjust their environment to avoid heat, cold or dirt as they would in natural conditions. The added weight and overcrowding also puts a strain on their hearts and lungs and Ascites can develop. In the UK, up to 19 million broilers die in their sheds from heart failure each year. In the case of no ventilation due to power failure during a heat wave 20,000 chicken can die in a short period of time. In a good grow out a farmer should sell between 92 to 96 percent of their flock. With a 1.80 to a 2.0 feed conversion ratio. After the marking of birds the farmer must clean out and repair for another flock. A farmer should average 4 to 5 grow outs a year.[22]

    Indoor with higher welfare

    Chickens are kept indoors but with more space (around 12 to 14 birds per square metre). They have a richer environment for example with natural light or straw bales that encourage foraging and perching. The chickens grow more slowly and live for up to two weeks longer than intensively farmed birds.[citation needed] The benefits of higher welfare indoor systems are the reduced growth rate, less crowding and more opportunities for natural behaviour.[8]

    Free-range broilers


    Turkeys on pasture at an organic farm
    Free-range broilers are reared under similar conditions to free-range egg laying hens. The breeds grow more slowly than those used for indoor rearing and usually reach slaughter weight at approximately 8 weeks of age. In the EU, each chicken must have one square metre of outdoor space.[8] The benefits of free-range poultry farming include opportunities for natural behaviours such as pecking, scratching, foraging and exercise outdoors. Because they grow slower and have opportunities for exercise, free-range broilers often have better leg and heart health.[8]

    Organic broilers

    Organic broiler chickens are reared under similar conditions to free-range broilers but with restrictions on the routine use of in-feed or in-water medications, other food additives and synthetic amino acids. The breeds used are slower growing, more traditional breeds and typically reach slaughter weight at around 12 weeks of age.[23] They have a larger space allowance outside (at least 2 square metres and sometimes up to 10 square metres per bird).[4] The Soil Association standards[11] indicate a maximum outdoors stocking density of 2,500 birds per hectare and a maximum of 1,000 broilers per poultry house.

    Issues with poultry farming

    Humane treatment


    Battery cages

    Chickens transported in a truck.
    Animal welfare groups have frequently criticized the poultry industry for engaging in practices which they believe to be inhumane. Many animal rights advocates object to killing chickens for food, the "factory farm conditions" under which they are raised, methods of transport, and slaughter. Compassion Over Killing and other groups have repeatedly conducted undercover investigations at chicken farms and slaughterhouses which they allege confirm their claims of cruelty.[24]
    Conditions in chicken farms may be unsanitary, allowing the proliferation of diseases such as salmonella, E. coli and campylobacter.[25] Chickens may be raised in very low light intensities, sometimes total darkness, to reduce injurious pecking. Concerns have been raised that companies growing single varieties of birds for eggs or meat are increasing their susceptibility to disease. Rough handling, crowded transport during various weather conditions and the failure of existing stunning systems to render the birds unconscious before slaughter, have also been cited as welfare concerns.
    A common practice among hatcheries for egg-laying hens is the culling of newly hatched male chicks since they do not lay eggs and do not grow fast enough to be profitable for meat.

    Beak trimming

    Main article: Debeaking
    Laying hens are routinely beak-trimmed at 1 day of age to reduce the damaging effects of aggression, feather pecking and cannibalism. Scientific studies (see below) have shown that beak trimming is likely to cause both acute and chronic pain.
    The beak is a complex, functional organ with an extensive nervous supply including nociceptors that sense pain and noxious stimuli.[26][27] These would almost certainly be stimulated during beak trimming, indicating strongly that acute pain would be experienced. Behavioural evidence of pain after beak trimming in layer hen chicks has been based on the observed reduction in pecking behavior, reduced activity and social behavior, and increased sleep duration.[28][29][30][31] Severe beak trimming, or beak trimming birds at an older age, may cause chronic pain. Following beak trimming of older or adult hens, the nociceptors in the beak stump show abnormal patterns of neural discharge, which indicate acute pain.[26][32][33][34]
    Neuromas, tangled masses of swollen regenerating axon sprouts,[35] are found in the healed stumps of birds beak trimmed at 5 weeks of age or older and in severely beak trimmed birds.[36] Neuromas have been associated with phantom pain in human amputees and have therefore been linked to chronic pain in beak trimmed birds. If beak trimming is severe because of improper procedure or done in older birds, the neuromas will persist which suggests that beak trimmed older birds experience chronic pain, although this has been debated.[37]
    Beak-trimmed chicks will initially peck less than non-trimmed chickens, which animal behavioralist Temple Grandin attributes to guarding against pain.[38] The animal rights activist, Peter Singer, claims this procedure is bad because beaks are sensitive, and the usual practice of trimming them without anaesthesia is considered inhumane by some.[39] Some within the chicken industry claim that beak-trimming is not painful[40] whereas others argue that the procedure causes chronic pain and discomfort, and decreases the ability to eat or drink.[39][41]

    Antibiotics

    Antibiotics have been used in poultry farming in large quantities since the 1940s. Around this time, it was found that the by-products of antibiotic production, fed because the antibiotic-producing mold had a high level of vitamin B12, produced better growth than could be accounted for by the vitamin B12 alone. Eventually it was discovered that the trace amounts of antibiotics remaining in the byproducts accounted for this growth.[42]
    The mechanism is apparently the adjustment of intestinal flora, favoring "good" bacteria while suppressing "bad" bacteria that provoke inflammation of the gut mucosa. So, the goal of antibiotics as a growth promoter is the same as for probiotics. Because the antibiotics used are not absorbed by the gut, they do not put antibiotics into the meat or eggs.[43]
    Antibiotics are used routinely in poultry for this reason, and also to prevent and treat disease. Many contend that this puts humans at risk as bacterial strains develop stronger and stronger resistances.[44]
    A proposed bill in the United States Congress would make the use of antibiotics in animal feed legal only for therapeutic (rather than preventative) use, but it has not been passed.[45] However, this may present the risk of slaughtered chickens harboring pathogenic bacteria and passing them on to humans that consume them.
    In October 2000, the U.S. Food and Drug Administration (FDA) discovered that two antibiotics were no longer effective in treating diseases found in factory-farmed chickens; one antibiotic was swiftly pulled from the market, but the other, Baytril, was not. Bayer, the company which produced it, contested the claim and as a result, Baytril remained in use until July 2005.[46]
    To prevent any residues of antibiotics in chicken meat, any given antibiotics are required to have a "withdrawal" period before they can be slaughtered. Samples of poultry at slaughter are randomly tested by the FSIS, and shows a very low percentage of residue violations [47]

    Arsenic

    Poultry feed can also include roxarsone or nitarsone, arsenical antimicrobial drugs that also promote growth. Roxarsone was used as a broiler starter by about 70% of the broiler growers between 1995 to 2000.[48] The drugs have generated controversy because it contains arsenic, which is highly toxic to humans. This arsenic could be transmitted through run-off from the poultry yards. A 2004 study by the U.S. magazine Consumer Reports reported "no detectable arsenic in our samples of muscle" but found "A few of our chicken-liver samples has an amount that according to EPA standards could cause neurological problems in a child who ate 2 ounces of cooked liver per week or in an adult who ate 5.5 ounces per week." The U.S. Food and Drug Administration (FDA), however, is the organization responsible for the regulation of foods in America, and all samples tested were "far less than the... amount allowed in a food product."[45]

    Roxarsone, a controversial arsenic compound used as a nutritional supplement for chickens.

    Growth hormones

    Hormone use in poultry production is illegal in the United States.[21][49][50] Similarly, no chicken meat for sale in Australia is fed hormones.[51] Several scientific studies have documented the fact that chickens grow rapidly because they are bred to do so, not because of growth hormones.[52][53] A small producer of natural and organic chickens confirmed this assumption:

    E. coli

    According to Consumer Reports, "1.1 million or more Americans [are] sickened each year by undercooked, tainted chicken." A USDA study discovered E. coli (Biotype I) in 99% of supermarket chicken, the result of chicken butchering not being a sterile process.[55] However, the same study also shows that the strain of E. coli found was always a non-lethal form, and no chicken had any of the pathenogenic O157:H7 serotype.[55] Many of these chickens, furthermore, had relatively low levels of contamination.[56]
    Feces tend to leak from the carcass until the evisceration stage, and the evisceration stage itself gives an opportunity for the interior of the carcass to receive intestinal bacteria. (So does the skin of the carcass, but the skin presents a better barrier to bacteria and reaches higher temperatures during cooking). Before 1950, this was contained largely by not eviscerating the carcass at the time of butchering, deferring this until the time of retail sale or in the home. This gave the intestinal bacteria less opportunity to colonize the edible meat. The development of the "ready-to-cook broiler" in the 1950s added convenience while introducing risk, under the assumption that end-to-end refrigeration and thorough cooking would provide adequate protection. E. coli can be killed by proper cooking times, but there is still some risk associated with it, and its near-ubiquity in commercially farmed chicken is troubling to some. Irradiation has been proposed as a means of sterilizing chicken meat after butchering.
    Salmonella too can be stressful on poultry production, how it causes disease has been investigated in some detail.[57]

    Avian influenza

    Main article: Avian influenza
    There is also a risk that crowded conditions in chicken farms will allow avian influenza (bird flu) to spread quickly. A United Nations press release states: "Governments, local authorities and international agencies need to take a greatly increased role in combating the role of factory-farming, commerce in live poultry, and wildlife markets which provide ideal conditions for the virus to spread and mutate into a more dangerous form..."[58]

    Efficiency

    Farming of chickens on an industrial scale relies largely on high protein feeds derived from soyabeans; in the European Union the soybean dominates the protein supply for animal feed,[59] and the poultry industry is the largest consumer of such feed.[59] Two kilograms of grain must be fed to poultry to produce 1 kg of weight gain,[60] much less than that required for pork or beef.[61] However, for every gram of protein consumed, chickens yield only 0.33 g of edible protein.[62]

    Economic factors

    Changes in commodity prices for poultry feed have a direct effect on the cost of doing business in the poultry industry. For instance, a significant rise in the price of corn in the United States can put significant economic pressure on large industrial chicken farming operations.[63]

    World chicken population

    The Food and Agriculture Organization of the United Nations estimated that in 2002 there were nearly sixteen billion chickens in the world, counting a total population of 15,853,900,000.[64] The figures from the Global Livestock Production and Health Atlas for 2004 were as follows:
  • China (3,860,000,000)
  • United States (1,970,000,000)
  • Indonesia (1,200,000,000)
  • Brazil (1,100,000,000)
  • India (648,830,000)[65]
  • Mexico (540,000,000)
  • Russia (340,000,000)
  • Japan (286,000,000)
  • Iran (280,000,000)
  • Turkey (250,000,000)
  • Bangladesh (172,630,000)
  • Nigeria (143,500,000)
In 2009 the annual chicken population in factory farms was estimated at 50 billion, with 6 billion raised in the European Union, over 9 billion raised in the United States and more than 7 billion in China.[66]

See also

Portal icon Agriculture and Agronomy portal

References

  1. "Compassion in World Farming - Poultry". Ciwf.org.uk. Retrieved August 26, 2011.
  2. State of the World 2006 World watch Institute, p. 26
  3. "Performance Records of Hy-Line Grey". Retrieved November 18, 2011.
  4. "Compassion in World Farming - Egg laying hens". Ciwf.org.uk. Retrieved August 26, 2011.
  5. "European Union Regulation for marketing standards for eggs - page 25". Retrieved August 26, 2011.
  6. "50% of UK eggs laid by free range hens". The Ranger. Retrieved November 18, 2011.
  7. "Chicken Feed: Grass-Fed Chickens & Pastured Poultry". Lions Grip. Retrieved July 6, 2007.
  8. "Compassion in World Farming - Poultry - Higher welfare alternatives". Ciwf.org.uk. Retrieved August 26, 2011.
  9. Sherwin, C., Richards, G. and Nicol, C. (2010). "A comparison of the welfare of layer hens in four housing systems used in the UK". British Poultry Science. 51 (4): 488–499.
  10. WSPA International> 'Free-range farming and avian flu in Asia retrieved July 6, 2007
  11. "Soil Association Standards". Retrieved December 5, 2011.
  12. Appleby, M.C., Hughes, B.O. and Elson, H.A. (1992). Poultry Production Systems: Behaviour, Management and Welfare. CAB International, Wallingford, UK.
  13. "European Union Council Directive 1999/74/EC". Retrieved November 15, 2011.
  14. VEGA Laying hens, free range and bird flu retrieved July 6, 2007
  15. Chickens: Layer Housing, Michael C. Appleby, Encyclopedia of Animal Science. doi:10.1081/E-EAS-120019534
  16. Housing, space, feed and water United Egg Producers
  17. "Animal Pragmatism: Compassion Over Killing Wants to Make the Anti-Meat Message a Little More Palatable". Washington Post. September 3, 2003. Retrieved July 30, 2009.
  18. Appleby, M.C.; J.A. Mench and B.O. Hughes (2004). Poultry Behaviour and Welfare. Wallingford and Cambridge MA: CABI Publishing. ISBN 0-85199-667-1.
  19. "Defra Code For The Welfare Of Laying Hens". Retrieved December 5, 2011.
  20. "Animal Welfare For Broiler Chickens". National Chicken Council. Retrieved June 21, 2012.
  21. "Poultry Industry Frequently Asked Questions". U.S Poultry & Egg Association. Retrieved June 21, 2012.
  22. "Compassion in World Farming - Meat chickens - Welfare issues". Ciwf.org.uk. Retrieved August 26, 2011.
  23. "Compassion in World Farming - Meat chickens". Ciwf.org.uk. Retrieved August 26, 2011.
  24. "Undercover Investigations :: Compassion Over Killing Investigation". Kentucky Fried Cruelty. Retrieved August 26, 2011.
  25. Wenonah Hauter, How the USDA Cowers to the Poultry Industry, AlterNet, 2014.02.20
  26. Breward, J., (1984). Cutaneous nociceptors in the chicken beak. Proceedings of the Journal of Physiology, London 346: 56
  27. Gentle, M.J., (1992). Pain in birds. Animal Welfare, 1: 235-247
  28. Gentle M.J., Hughes B.O. and Hubrecht R.C., (1982). The effect of beak-trimming on food-intake, feeding behaviour and body weight in adult hens. Applied Animal Ethology, 8: 147–157
  29. Duncan I.J.H., Slee G.S., Seawright E. and Breward J., (1989). Behavioural consequences of partial beak amputation (beak trimming) in poultry. British Poultry Science, 30: 479–488
  30. Gentle M.J., Hunter L.N. and Waddington D., (1991). The onset of pain related behaviours following partial beak amputation in the chicken. Neuroscience Letters, 128: 113–116
  31. Gentle, M.J., Hughes, B.O., Fox, A. and Waddington, D., (1997). Behavioural and anatomical consequences of two beak trimming methods in 1- and 10-d-old domestic chicks. British Poultry Science, 38: 453-463
  32. Breward, J., (1985). An Electrophysiological Investigation of the Effects of Beak Trimming in the Domestic Fowl (Gallus gallus domesticus). Ph.D. thesis, University of Edinburgh.
  33. Gentle, M.J., (1986). Beak trimming in poultry. World’s Poultry Science Journal', 42: 268-275
  34. Breward, L. and Gentle, M.J., (1985). Neuroma formation and abnormal afferent nerve discharges after partial break amputation (beak trimming) in poultry. Experientia, 41: 1132-1134. doi:10.1007/BF01951693
  35. Devor, M. and Rappaport, Z.H., (1990). Pain Syndromes in Neurology., edited by H.L. Fields, Butterworths, London, p. 47.
  36. Lunam, C.A., Glatz, P.C. and Hsu, Y-J., (1996). The absence of neuromas in beaks of adult hens after conservative trimming at hatch. Australian Veterinary Journal, 74: 46-49
  37. Kuenzel, W.J. (2001). Neurobiological basis of sensory perception: welfare implications of beak trimming. Poultry Science, 86: 1273-1282
  38. Grandin, Temple; Johnson, Catherine (2005). Animals in Translation. New York, NY: Scribner. p. 183. ISBN 0-7432-4769-8.
  39. Singer, Peter (2006). In Defense of Animals. Wiley-Blackwell. p. 176. ISBN 1-4051-1941-1.
  40. Hernandez, Nelson (September 19, 2005). "Advocates Challenge Humane-Care Label on Md. Eggs". Washington Post. Retrieved July 30, 2009.
  41. "Md. Egg Farm Accused of Cruelty". Washington Post. June 6, 2001. Retrieved July 30, 2009.
  42. Ewing, Poultry Nutrition, 5th ed., 1963, p. 1283.
  43. Ewing, Poultry Nutrition, 5th ed., 1963, p. 1284.
  44. "UNL.edu". Retrieved August 26, 2011.
  45. "Chicken: Arsenic and antibiotics". ConsumerReports.org. Retrieved March 24, 2009.
  46. Baytril: FDA Bans Bayer Antibiotic for Poultry Use Randy Fabi / Reuters, July 29, 2005[dead link]
  47. "Chicken from Farm to Table | USDA Food Safety and Inspection Service". Fsis.usda.gov. April 6, 2011. Retrieved August 26, 2011.
  48. Jones, F. T. (2007). "A Broad View of Arsenic". Poultry Science 86 (1): 2–14. doi:10.1093/ps/86.1.2. PMID 17179408.
  49. "The Use Of Steroid Hormones For Growth Promotion In Food-Producing Animals"
  50. "Chicken from Farm to Table | USDA Food Safety and Inspection Service". Fsis.usda.gov. April 6, 2011. Retrieved August 26, 2011.
  51. "Landline - 5/05/2002: Challenging food safety myths . Australian Broadcasting Corp". Abc.net.au. May 5, 2002. Retrieved August 26, 2011.
  52. Havenstein GB, Ferket PR, Qureshi MA (October 2003). "Carcass composition and yield of 1957 versus 2001 broilers when fed representative 1957 and 2001 broiler diets". Poult. Sci. 82 (10): 1509–18. doi:10.1093/ps/82.10.1509. PMID 14601726.
  53. Havenstein GB, Ferket PR, Scheideler SE, Rives DV (December 1994). "Carcass composition and yield of 1991 vs 1957 broilers when fed "typical" 1957 and 1991 broiler diets". Poult. Sci. 73 (12): 1795–804. doi:10.3382/ps.0731795. PMID 7877935.
  54. Robert Plamondon. "Chicken Myths and Scams". Plamondon.com. Retrieved November 24, 2008.
  55. "Nationwide Broiler Chicken Microbiological Baseline Data Collection Program July 1994 - June 1995". Retrieved November 6, 2012.
  56. "Revised Young Chicken Baseline" (PDF). Retrieved August 26, 2011.
  57. Yashroy, Rakesh. "Poultry production under Salmonella stress: Infection mechanisms". Research Gate. Retrieved November 18, 2014.
  58. "UN task forces battle misconceptions of avian flu, mount Indonesian campaign". UN News Center. Retrieved July 24, 2009.
  59. "Protein Sources For The Animal Feed Industry". Fao.org. May 3, 2002. Retrieved August 26, 2011.
  60. Lester R. Brown (2003). "Chapter 8. Raising Land Productivity: Raising protein efficiency". Plan B: Rescuing a Planet Under Stress and a Civilization in Trouble. NY: W.W. Norton & Co. ISBN 0-393-05859-X.
  61. Adler, Jerry; Lawler, Andrew (June 2012). "How the Chicken Conquered the World". Smithsonian. Retrieved May 27, 2012.
  62. Tom Lovell (1998). Nutrition and feeding of fish. Springer. p. 9. ISBN 978-0-412-07701-2.
  63. Jonathan Starkey (April 9, 2011). "Delaware business: Chicken companies feeling pinch as corn prices soar". News Journal (Gannett). DelawareOnline. OCLC 38962480. Retrieved April 10, 2011
  64. "Chicken population". Fao.org. Retrieved August 26, 2011.
  65. http://dahd.nic.in/dahd/WriteReadData/Annual%20Report%202010-11%20English.pdf
  66. Foer, Jonathan Safran (2009). "Eating Animals", Page 136. Little, Brown and Company, USA. ISBN 978-0-316-06990-8

  •  

Posted by at No comments:
Subscribe to: Posts (Atom)