O espaço de comedouro por leitão deve ser suficiente para assegurar um acesso adequado ao alimento, sem prejudicar o consumo e o desempenho. No entanto a influência do espaço de comedouro no desempenho pós-desmame ainda não está bem estabelecida, principalmente para leitões sujeitos a uma alta densidade na fase de creche. O objetivo desse estudo foi verificar o efeito de quatro espaços de comedouro no início do consumo de alimento, consumo médio diário (CMD), ganho de peso diário (GPD), conversão alimentar (CA) e ocorrência de canibalismo em leitões submetidos a uma densidade de 0,23 m²/leitão, na fase de creche. Foram avaliados 630 leitões com peso médio de desmame 5,59 ± 0,9 kg e idade média de 20,5 ± 0,9 dias ao longo de um período de 6 semanas. Foram utilizadas 28 baias com sete repetições por tratamento, sendo a baia a unidade experimental. Os espaços de comedouro estudados foram 2,13 cm/leitão, 2,56 cm/leitão, 3,20 cm/leitão e 4,26 cm/leitão. A ração foi disponibilizada na forma ad libitum, com registro de consumo diário. Os leitões receberam, por um período de três dias pós-desmame, ração com corante de óxido de ferro a 1% e foram submetidos a swab retal nas 18, 24, 42, 50, 58 e 66 h pós-desmame para avaliar o início do hábito de consumo alimentar. Os leitões foram pesados nos dias 7, 14, 21, 28, 35 e 42 de alojamento, sendo observada e registrada, diariamente, a ocorrência de canibalismo de cauda e orelha. Houve redução no início do consumo alimentar (P<0,001) quanto maior foi o espaço de comedouro disponibilizado. Para o período de 0 a 14 dias pós-desmame, foi observado efeito linear significativo no CMD (P=0,015). Houve uma tendência linear de melhoria para o GPD quanto maior foi o espaço de comedouro disponível (P=0,062), mas não foram observados efeitos do espaço de comedouro nas variáveis CMD e CA (P>0,05), no período total (0 a 42 dias). A partir dos 21 dias pós-alojamento, foram observados quadros de canibalismo tanto de orelha como cauda. O tratamento de 4,26 cm/leitão foi o único a não apresentar canibalismo e diferiu de todos os outros tratamentos. O espaço de 2,13 cm/leitão foi o que apresentou os maiores percentuais de canibalismo, em comparação com os demais espaços. Em conclusão, maior espaço de comedouro reduz o tempo médio para início do consumo pós-desmame, tende a aumentar o GPD, além de melhorar o bem-estar, pela redução de canibalismo, em leitões alojados em uma alta densidade na fase de creche. / Feeder space per pig should be sufficient to ensure adequate access to feed, without impairing the consumption and performance of the animals. However, the influence of feeder space on growth performance of pigs is not well established for the nursery phase, mainly in scenarios of high stocking density. The aim of this study was to investigate the effect of four different feeder spaces on the beggining of feeding behavior, the average daily gain (ADG), average daily feed intake (ADFI), feeding efficiency and the occurrence of tail and ear biting in pigs under a stocking density of 0.23 m²/pig in nursery phase. A total of 630 weaned piglets weighing 5.59 ± 0.9 kg and ageing 20.5 ± 0.9 days were evaluated over a 6 weeks period. Seven replicates (28 pens) per treatment were used. The feeder spaces were 2.13 cm/pig, 2.56 cm/pig, 3.20 cm/pig and 4.26 cm/pig. The feed was offered ad libitum, with the feed intake being recorded daily. The pigs were fed for a three-days post-weaning period, with 1% iron oxide dye, and were submitted to rectal swab at 18, 24, 42, 50, 58 and 66 h post-weaning to determine the starting of the feeding behavior. The piglets were weighed at 7, 14, 21, 28, 35 and 42 days of housing. The appearance of tail and ear biting was daily recorded. There was a reduction in the period between weaning and first feed intake (P<0.001) as the feeder space available increased. For the period of 0 to 14 d post-weaning, feeder space linearly affected the increase of ADFI (P=0.015). There was a linear trend for increased GPD with higher feeder space available (P=0.062), but no statistical effect of feeder space was observed on ADFI and feeding efficiency (P>0.05), when considering the total nursery period (0-42 days). From day 21 post-weaning onward, tail and ear biting behavior were observed. Piglets submitted to 4.26 cm/pig were the only that did not present this behavior, differing (P<0.05) from all the other treatments. The space of 2.13 cm/pig presented the highest percentages (P<0.05) of total cannibalism in comparison with the others spaces. In conclusion, higher feeder space decreases the time for the beginning of feeding behavior, tends to increase the ADG, as well as improves the welfare by reducing cannibalism among piglets under high stocking density pens in the nursery phase.

Two standard graph representations for linear codes are the Tanner graph and the tailbiting trellis. Such graph representations allow the decoding problem for a code to be phrased as a computational problem on the corresponding graph and yield graph theoretic criteria for good codes. When a Tanner graph for a code is used for communication across a binary erasure channel (BEC) and decoding is performed using the standard iterative decoding algorithm, the maximum number of correctable erasures is determined by the stopping distance of the Tanner graph. Hence the computational problem of determining the stopping distance of a Tanner graph is of interest. In this thesis it is shown that computing stopping distance of a Tanner graph is NP hard. It is also shown that there can be no (1 + є ) approximation algorithm for the problem for any є > 0 unless P = NP and that approximation ratio of 2(log n)1- є for any є > 0 is impossible unless NPCDTIME(npoly(log n)). One way to construct Tanner graphs of large stopping distance is to ensure that the graph has large girth. It is known that stopping distance increases exponentially with the girth of the Tanner graph. A new elementary combinatorial construction algorithm for an almost regular LDPC code family with provable Ώ(log n) girth and O(n2) construction complexity is presented. The bound on the girth is close within a factor of two to the best known upper bound on girth. The problem of linear time exact maximum likelihood decoding of tailbiting trellis has remained open for several years. An O(n) complexity approximate maximum likelihood decoding algorithm for tail-biting trellises is presented and analyzed. Experiments indicate that the algorithm performs close to the ideal maximum likelihood decoder.

O espaço de comedouro por leitão deve ser suficiente para assegurar um acesso adequado ao alimento, sem prejudicar o consumo e o desempenho. No entanto a influência do espaço de comedouro no desempenho pós-desmame ainda não está bem estabelecida, principalmente para leitões sujeitos a uma alta densidade na fase de creche. O objetivo desse estudo foi verificar o efeito de quatro espaços de comedouro no início do consumo de alimento, consumo médio diário (CMD), ganho de peso diário (GPD), conversão alimentar (CA) e ocorrência de canibalismo em leitões submetidos a uma densidade de 0,23 m²/leitão, na fase de creche. Foram avaliados 630 leitões com peso médio de desmame 5,59 ± 0,9 kg e idade média de 20,5 ± 0,9 dias ao longo de um período de 6 semanas. Foram utilizadas 28 baias com sete repetições por tratamento, sendo a baia a unidade experimental. Os espaços de comedouro estudados foram 2,13 cm/leitão, 2,56 cm/leitão, 3,20 cm/leitão e 4,26 cm/leitão. A ração foi disponibilizada na forma ad libitum, com registro de consumo diário. Os leitões receberam, por um período de três dias pós-desmame, ração com corante de óxido de ferro a 1% e foram submetidos a swab retal nas 18, 24, 42, 50, 58 e 66 h pós-desmame para avaliar o início do hábito de consumo alimentar. Os leitões foram pesados nos dias 7, 14, 21, 28, 35 e 42 de alojamento, sendo observada e registrada, diariamente, a ocorrência de canibalismo de cauda e orelha. Houve redução no início do consumo alimentar (P<0,001) quanto maior foi o espaço de comedouro disponibilizado. Para o período de 0 a 14 dias pós-desmame, foi observado efeito linear significativo no CMD (P=0,015). Houve uma tendência linear de melhoria para o GPD quanto maior foi o espaço de comedouro disponível (P=0,062), mas não foram observados efeitos do espaço de comedouro nas variáveis CMD e CA (P>0,05), no período total (0 a 42 dias). A partir dos 21 dias pós-alojamento, foram observados quadros de canibalismo tanto de orelha como cauda. O tratamento de 4,26 cm/leitão foi o único a não apresentar canibalismo e diferiu de todos os outros tratamentos. O espaço de 2,13 cm/leitão foi o que apresentou os maiores percentuais de canibalismo, em comparação com os demais espaços. Em conclusão, maior espaço de comedouro reduz o tempo médio para início do consumo pós-desmame, tende a aumentar o GPD, além de melhorar o bem-estar, pela redução de canibalismo, em leitões alojados em uma alta densidade na fase de creche. / Feeder space per pig should be sufficient to ensure adequate access to feed, without impairing the consumption and performance of the animals. However, the influence of feeder space on growth performance of pigs is not well established for the nursery phase, mainly in scenarios of high stocking density. The aim of this study was to investigate the effect of four different feeder spaces on the beggining of feeding behavior, the average daily gain (ADG), average daily feed intake (ADFI), feeding efficiency and the occurrence of tail and ear biting in pigs under a stocking density of 0.23 m²/pig in nursery phase. A total of 630 weaned piglets weighing 5.59 ± 0.9 kg and ageing 20.5 ± 0.9 days were evaluated over a 6 weeks period. Seven replicates (28 pens) per treatment were used. The feeder spaces were 2.13 cm/pig, 2.56 cm/pig, 3.20 cm/pig and 4.26 cm/pig. The feed was offered ad libitum, with the feed intake being recorded daily. The pigs were fed for a three-days post-weaning period, with 1% iron oxide dye, and were submitted to rectal swab at 18, 24, 42, 50, 58 and 66 h post-weaning to determine the starting of the feeding behavior. The piglets were weighed at 7, 14, 21, 28, 35 and 42 days of housing. The appearance of tail and ear biting was daily recorded. There was a reduction in the period between weaning and first feed intake (P<0.001) as the feeder space available increased. For the period of 0 to 14 d post-weaning, feeder space linearly affected the increase of ADFI (P=0.015). There was a linear trend for increased GPD with higher feeder space available (P=0.062), but no statistical effect of feeder space was observed on ADFI and feeding efficiency (P>0.05), when considering the total nursery period (0-42 days). From day 21 post-weaning onward, tail and ear biting behavior were observed. Piglets submitted to 4.26 cm/pig were the only that did not present this behavior, differing (P<0.05) from all the other treatments. The space of 2.13 cm/pig presented the highest percentages (P<0.05) of total cannibalism in comparison with the others spaces. In conclusion, higher feeder space decreases the time for the beginning of feeding behavior, tends to increase the ADG, as well as improves the welfare by reducing cannibalism among piglets under high stocking density pens in the nursery phase.

O espaço de comedouro por leitão deve ser suficiente para assegurar um acesso adequado ao alimento, sem prejudicar o consumo e o desempenho. No entanto a influência do espaço de comedouro no desempenho pós-desmame ainda não está bem estabelecida, principalmente para leitões sujeitos a uma alta densidade na fase de creche. O objetivo desse estudo foi verificar o efeito de quatro espaços de comedouro no início do consumo de alimento, consumo médio diário (CMD), ganho de peso diário (GPD), conversão alimentar (CA) e ocorrência de canibalismo em leitões submetidos a uma densidade de 0,23 m²/leitão, na fase de creche. Foram avaliados 630 leitões com peso médio de desmame 5,59 ± 0,9 kg e idade média de 20,5 ± 0,9 dias ao longo de um período de 6 semanas. Foram utilizadas 28 baias com sete repetições por tratamento, sendo a baia a unidade experimental. Os espaços de comedouro estudados foram 2,13 cm/leitão, 2,56 cm/leitão, 3,20 cm/leitão e 4,26 cm/leitão. A ração foi disponibilizada na forma ad libitum, com registro de consumo diário. Os leitões receberam, por um período de três dias pós-desmame, ração com corante de óxido de ferro a 1% e foram submetidos a swab retal nas 18, 24, 42, 50, 58 e 66 h pós-desmame para avaliar o início do hábito de consumo alimentar. Os leitões foram pesados nos dias 7, 14, 21, 28, 35 e 42 de alojamento, sendo observada e registrada, diariamente, a ocorrência de canibalismo de cauda e orelha. Houve redução no início do consumo alimentar (P<0,001) quanto maior foi o espaço de comedouro disponibilizado. Para o período de 0 a 14 dias pós-desmame, foi observado efeito linear significativo no CMD (P=0,015). Houve uma tendência linear de melhoria para o GPD quanto maior foi o espaço de comedouro disponível (P=0,062), mas não foram observados efeitos do espaço de comedouro nas variáveis CMD e CA (P>0,05), no período total (0 a 42 dias). A partir dos 21 dias pós-alojamento, foram observados quadros de canibalismo tanto de orelha como cauda. O tratamento de 4,26 cm/leitão foi o único a não apresentar canibalismo e diferiu de todos os outros tratamentos. O espaço de 2,13 cm/leitão foi o que apresentou os maiores percentuais de canibalismo, em comparação com os demais espaços. Em conclusão, maior espaço de comedouro reduz o tempo médio para início do consumo pós-desmame, tende a aumentar o GPD, além de melhorar o bem-estar, pela redução de canibalismo, em leitões alojados em uma alta densidade na fase de creche. / Feeder space per pig should be sufficient to ensure adequate access to feed, without impairing the consumption and performance of the animals. However, the influence of feeder space on growth performance of pigs is not well established for the nursery phase, mainly in scenarios of high stocking density. The aim of this study was to investigate the effect of four different feeder spaces on the beggining of feeding behavior, the average daily gain (ADG), average daily feed intake (ADFI), feeding efficiency and the occurrence of tail and ear biting in pigs under a stocking density of 0.23 m²/pig in nursery phase. A total of 630 weaned piglets weighing 5.59 ± 0.9 kg and ageing 20.5 ± 0.9 days were evaluated over a 6 weeks period. Seven replicates (28 pens) per treatment were used. The feeder spaces were 2.13 cm/pig, 2.56 cm/pig, 3.20 cm/pig and 4.26 cm/pig. The feed was offered ad libitum, with the feed intake being recorded daily. The pigs were fed for a three-days post-weaning period, with 1% iron oxide dye, and were submitted to rectal swab at 18, 24, 42, 50, 58 and 66 h post-weaning to determine the starting of the feeding behavior. The piglets were weighed at 7, 14, 21, 28, 35 and 42 days of housing. The appearance of tail and ear biting was daily recorded. There was a reduction in the period between weaning and first feed intake (P<0.001) as the feeder space available increased. For the period of 0 to 14 d post-weaning, feeder space linearly affected the increase of ADFI (P=0.015). There was a linear trend for increased GPD with higher feeder space available (P=0.062), but no statistical effect of feeder space was observed on ADFI and feeding efficiency (P>0.05), when considering the total nursery period (0-42 days). From day 21 post-weaning onward, tail and ear biting behavior were observed. Piglets submitted to 4.26 cm/pig were the only that did not present this behavior, differing (P<0.05) from all the other treatments. The space of 2.13 cm/pig presented the highest percentages (P<0.05) of total cannibalism in comparison with the others spaces. In conclusion, higher feeder space decreases the time for the beginning of feeding behavior, tends to increase the ADG, as well as improves the welfare by reducing cannibalism among piglets under high stocking density pens in the nursery phase.

Codes can be represented by edge-labeled directed graphs called trellises, which are used in decoding with the Viterbi algorithm. We will first examine the well-known product construction for trellises and present an algorithm for recovering the factors of a given trellis. To maximize efficiency, trellises that are minimal in a certain sense are desired. It was shown by Koetter and Vardy that one can produce all minimal tail-biting trellises for a code by looking at a special set of generators for a code. These generators along with a set of spans comprise what is called a characteristic pair, and we will discuss how to determine the number of these pairs for a given code. Finally, we will look at trellis dualization, in which a trellis for a code is used to produce a trellis representing the dual code. The first method we discuss comes naturally with the known BCJR construction. The second, introduced by Forney, is a very general procedure that works for many different types of graphs and is based on dualizing the edge set in a natural way. We call this construction the local dual, and we show the necessary conditions needed for these two different procedures to result in the same dual trellis.

O presente trabalho avaliou a influência de lesões de caudofagia em suínos na terminação sobre o ganho de peso, variáveis sanitárias, ocorrência de lesões e condenações ao abate. O estudo foi realizado em quatro propriedades (PROP) de terminação de suínos. Para cada suíno com lesão de caudofagia foram selecionados dois controles, totalizando a avaliação dos seguintes números de animais: PROP1: 87; PROP2: 33; PROP3: 60; PROP4: 132. As lesões na cauda foram classificadas conforme o grau de severidade (escore de 0 a 4, sendo 0 normal e a severidade aumentando até os graus 2 e 3, e como grau 4 para lesões cicatrizadas). A cada uma de 4 a 6 avaliações (conforme a idade inicial do 1o diagnóstico do problema), os animais eram pesados e as lesões na cauda avaliadas. Em todas as propriedades, foi observada uma recuperação das lesões de caudofagia na terceira avaliação. Nas PROP 1 e 3, animais com lesões de escore 3 (severas) tiveram menor ganho de peso (P<0,05) comparados aos animais de escore 0. Além disso, na PROP3, animais com escore 3 foram menos pesados (P<0,05) ao abate do que aqueles de escore 0. A chance de animais com escore 3 terem artrite e apresentarem nódulos subcutâneos e/ou abscessos foi 25,5 e 30,4 vezes maior, respectivamente, em comparação aos animais com escore 0. Tanto animais com escore 2 (moderado) quanto os com escore 3 apresentaram maiores chances (P<0,05) de terem abscessos ou lesões pulmonares (pleurite e pneumonia embólica) em comparação aos animais sem lesão de cauda. Houve desvio ao Departamento de Inspeção Federal (DIF) de 21,6% (62/287) das carcaças, de animais com lesões e controles, sendo que a caudofagia foi a causa de 66,1% das condenações. Animais com lesões de escore 2 e 3 apresentaram 6,0 e 9,3 vezes maiores chances de terem suas carcaças desviadas ao DIF, respectivamente, comparados aos animais de escore 0. Os animais com lesões de caudofagia representaram 63,0% das carcaças que tiveram destino “não exportável” e 75,0% das carcaças com outros destinos. Considerando os percentuais aproximados de perdas relativas definidas pelo frigorífico visitado para as categorias de condenação (não-exportável, embutido, conserva e graxaria), isto representaria a perda de 15,58 animais (total de 18,12% entre os 86 animais que foram diagnosticados com caudofagia na granja). Isso permite concluir que, nas condições desse estudo, de cada 5 animais que são visualizados com canibalismo na terminação vai ocorrer a perda total de 1 no frigorífico. A esse prejuízo devem ser somados os animais que foram sacrificados nas granjas ou que vieram a morrer devido aos problemas causados pelas complicações das lesões na cauda. No estudo atual, foi possível determinar que, entre todos os que haviam apresentado lesões de canibalismo nas granjas, apenas dois mantinham lesões detectáveis externamente por ocasião do abate, o que pode ser explicado pela ocorrência muito precoce das lesões de caudofagia nos casos observados. Por outro lado, no abate desses animais do grupo com caudofagia, mas sem lesões externas no abate, foi observado um grande número de condenações por abscessos e lesões pulmonares. Isso sugere existir uma dicotomia entre as situações de campo e de frigorífico, reforçando a necessidade de uma melhor ligação entre esses contextos para estimar adequadamente o seu impacto. / The present work assessed the influence of tail biting lesions in finishing pigs in relation to weight gain, health, occurrence of lesions and carcass condemnation at slaughter. The study was carried out in four finishing units (PROP) and the following number of animals were assessed: PROP1: 87; PROP2: 33; PROP3: 60; PROP4: 132. To each animal with tail biting two controls were selected. Tail lesions were classified according the degrees of severity (scores from 0 to 4, 0 classified as normal and severity increasing until the degrees 2 and 3, and degree 4 meaning healed lesions). In each one of 4 to 6 visits (depending on the age of the 1st diagnosis of the problem), the animals were weighed and tail lesions assessed. In all farms, healing of tail lesions was observed in the third evaluation. In PROP 1 and 3, injured animals with score 3 showed smaller weight gain (P<0,05) when compared with animals with score 0. In PROP3, animals with score 3 were lighter (P<0,05) at slaughter than those with score 0. The chance for animals with score 3 to show arthritis and subcutaneous nodules and/or abscesses was 25,5 and 30,4 times higher, respectively, when compared with animals with score 0. Animals with scores 2 (moderate) and 3 (severe) had higher chances (P<0,05) of having abscesses or lung lesions (pleuritis and embolic pneumonia) when compared to animals without tail lesions. Trimming was observed in 21,6% (62/287) of the carcasses of injured and controls, and tail lesions corresponded to 66,1% among condemnations. Animals with lesions of scores 2 and 3 presented 6,0 and 9,3 higher chances of having trimmed carcasses, respectively, when compared with animals with score 0. Animals with tail lesion represented 63,0% of the carcasses with “non exportable” destination and 75,0% of the carcasses with other destinations. Considering the percentile of losses in each category defined by the slaughterhouse visited in this work (non exportable, processed, preserve and grease), this would represent a total loss of 15,58 animals (loss of a total of 18,82% among 86 animals with cannibalism). In the conditions of this study, this would mean that from 5 animals diagnosed with cannibalism in the finishing period, one would be totally wasted at the slaughter time. To this damage must be added the animals that were euthanazied in the herds or those died due to complications of tail injuries. In the present study, an individual diagnosis was performed in the farms of all animals with external lesions suggestive of tail cannibalism and all affected animals were followed at slaughter. Because of this, it was possible to observe that between all animals diagnosed with cannibalism at farm level, only two remained with lesions externally detectable at slaughter, what could be explained by the precocity of the lesions present in the cases analyzed by us. On the other hand, at the slaughter of this group of animals of the cannibalism group but without external lesions at slaughter, a great number of condemnations occurred by abscesses and lung lesions. This suggests that there is a dicotomy between slaughter and field situations, reinforcing the need for a better liaison between these contexts, to be able to adequately assess its impact.

In wireless communication system, convolution code has been one of the most popular error-correcting code. To prevent from the interference of noise during transmission, the transmitter usually applies convolution encode to code the processed information, and the receiver will use Viterbi decoder to decode and correct the error bit to decrease the bit error rate. In 3G mobile communication, such decoder is often applied between the base station and the communication device as a decoding mechanism. Since traditional decoders of communication devices consume more than one third power of the whole receiver, the present study focuses on the way effectively reducing the power consumption of Viterbi decoder. Traditional convolution coders use zero-tail, which make decoder be able to resist the interference of noise; however, this method would increase extra tail bits, which would decrease the code rate and affect the efficiency of transmission, especially for those information with short length, such as the header of packet. Tail-biting convolution code is another error-correcting code, which maintains the code rate, and it has been used in the control channel of LTE. Tail-biting convolution code is more complex than traditional decoder. Therefore, this thesis modifies the Wrap-Around Viterbi Algorithm (WAVA) to enormously decrease the power consuming while maintaining the bit error rate and the correctness of decoding. The aim of the present study is achieved by decreasing iteration number of WAVA algorithm to reduce one fourth of the whole power consumption. On the other hand, if the received information is not interfered by noise, it¡¦s unnecessary to turn on Tail-biting Convolution Decoder. As a result, the present study introduces the error detection circuit so that the received information can be simply decode and detected with the error detection circuit. If there is no noise interference, it can directly be outputted; if there is noise interference, however, it should be decoded by Tail-biting Convolution Decoder. The experimental results show that the survivor memory unit saves more than 60% power than traditional decoders, moreover, it will save 55%~88% power consumption when it goes with the error detection circuit. Consequently, the proposed method is indeed able to reduce the power consumption of Tail-biting Convolution Decoder. Keyword¡Gwireless communication, tail-biting convolution code, code rate, Viterbi decoder, power consumption

The objective of this research was to investigate the behavioural, physiological and immunological effects of routine surgical procedures in neonatal swine in order to provide producers with science-based recommendations. In the first experiment, low- or average-birth-weight piglets that were tail docked and ear notched at 1 or 3 days of age showed subtle differences resulting from age at processing. However, low-birth-weight male piglets had the lowest attendance during nursing bouts and spent the greatest amount of time lying alone. Vocalization data suggests that ABW piglets may be less reactive to the procedures on d 1. Overall, the decreased vitality and reduced survivability of low-birth-weight piglets suggests that delaying processing until day 3 for these piglets may be preferable. In the second experiment, the effects of docked tail length and nursery stocking density on tail-biting behaviour, skin lesions and rectal prolapses were investigated. Long-tailed pigs (docked to 4.5 cm at birth) were most vulnerable to tail-biting, and housing at a moderate versus high nursery stocking density was not sufficient to reduce tail-biting. High nursery stocking density negatively impacted skin lesion scoring and growth performance for the majority of the grower-finisher period. Pigs from either nursery stocking density and docked tail length groups were equally likely to be affected by prolapsed rectal mucosa. Given the decreased survivability and significantly lighter weaning weight for low-birth-weight piglets compared to those of average-birth-weight, delaying processing of low-birth-weight piglets may be the most humane option. Further, until tail-biting is better understood and a more effective solution found, the routine docking of tails remains the optimal method for balancing a situation with enormous welfare-reducing potential. / Agriculture and Agri-Food Canada

O presente trabalho avaliou a influência de lesões de caudofagia em suínos na terminação sobre o ganho de peso, variáveis sanitárias, ocorrência de lesões e condenações ao abate. O estudo foi realizado em quatro propriedades (PROP) de terminação de suínos. Para cada suíno com lesão de caudofagia foram selecionados dois controles, totalizando a avaliação dos seguintes números de animais: PROP1: 87; PROP2: 33; PROP3: 60; PROP4: 132. As lesões na cauda foram classificadas conforme o grau de severidade (escore de 0 a 4, sendo 0 normal e a severidade aumentando até os graus 2 e 3, e como grau 4 para lesões cicatrizadas). A cada uma de 4 a 6 avaliações (conforme a idade inicial do 1o diagnóstico do problema), os animais eram pesados e as lesões na cauda avaliadas. Em todas as propriedades, foi observada uma recuperação das lesões de caudofagia na terceira avaliação. Nas PROP 1 e 3, animais com lesões de escore 3 (severas) tiveram menor ganho de peso (P<0,05) comparados aos animais de escore 0. Além disso, na PROP3, animais com escore 3 foram menos pesados (P<0,05) ao abate do que aqueles de escore 0. A chance de animais com escore 3 terem artrite e apresentarem nódulos subcutâneos e/ou abscessos foi 25,5 e 30,4 vezes maior, respectivamente, em comparação aos animais com escore 0. Tanto animais com escore 2 (moderado) quanto os com escore 3 apresentaram maiores chances (P<0,05) de terem abscessos ou lesões pulmonares (pleurite e pneumonia embólica) em comparação aos animais sem lesão de cauda. Houve desvio ao Departamento de Inspeção Federal (DIF) de 21,6% (62/287) das carcaças, de animais com lesões e controles, sendo que a caudofagia foi a causa de 66,1% das condenações. Animais com lesões de escore 2 e 3 apresentaram 6,0 e 9,3 vezes maiores chances de terem suas carcaças desviadas ao DIF, respectivamente, comparados aos animais de escore 0. Os animais com lesões de caudofagia representaram 63,0% das carcaças que tiveram destino “não exportável” e 75,0% das carcaças com outros destinos. Considerando os percentuais aproximados de perdas relativas definidas pelo frigorífico visitado para as categorias de condenação (não-exportável, embutido, conserva e graxaria), isto representaria a perda de 15,58 animais (total de 18,12% entre os 86 animais que foram diagnosticados com caudofagia na granja). Isso permite concluir que, nas condições desse estudo, de cada 5 animais que são visualizados com canibalismo na terminação vai ocorrer a perda total de 1 no frigorífico. A esse prejuízo devem ser somados os animais que foram sacrificados nas granjas ou que vieram a morrer devido aos problemas causados pelas complicações das lesões na cauda. No estudo atual, foi possível determinar que, entre todos os que haviam apresentado lesões de canibalismo nas granjas, apenas dois mantinham lesões detectáveis externamente por ocasião do abate, o que pode ser explicado pela ocorrência muito precoce das lesões de caudofagia nos casos observados. Por outro lado, no abate desses animais do grupo com caudofagia, mas sem lesões externas no abate, foi observado um grande número de condenações por abscessos e lesões pulmonares. Isso sugere existir uma dicotomia entre as situações de campo e de frigorífico, reforçando a necessidade de uma melhor ligação entre esses contextos para estimar adequadamente o seu impacto. / The present work assessed the influence of tail biting lesions in finishing pigs in relation to weight gain, health, occurrence of lesions and carcass condemnation at slaughter. The study was carried out in four finishing units (PROP) and the following number of animals were assessed: PROP1: 87; PROP2: 33; PROP3: 60; PROP4: 132. To each animal with tail biting two controls were selected. Tail lesions were classified according the degrees of severity (scores from 0 to 4, 0 classified as normal and severity increasing until the degrees 2 and 3, and degree 4 meaning healed lesions). In each one of 4 to 6 visits (depending on the age of the 1st diagnosis of the problem), the animals were weighed and tail lesions assessed. In all farms, healing of tail lesions was observed in the third evaluation. In PROP 1 and 3, injured animals with score 3 showed smaller weight gain (P<0,05) when compared with animals with score 0. In PROP3, animals with score 3 were lighter (P<0,05) at slaughter than those with score 0. The chance for animals with score 3 to show arthritis and subcutaneous nodules and/or abscesses was 25,5 and 30,4 times higher, respectively, when compared with animals with score 0. Animals with scores 2 (moderate) and 3 (severe) had higher chances (P<0,05) of having abscesses or lung lesions (pleuritis and embolic pneumonia) when compared to animals without tail lesions. Trimming was observed in 21,6% (62/287) of the carcasses of injured and controls, and tail lesions corresponded to 66,1% among condemnations. Animals with lesions of scores 2 and 3 presented 6,0 and 9,3 higher chances of having trimmed carcasses, respectively, when compared with animals with score 0. Animals with tail lesion represented 63,0% of the carcasses with “non exportable” destination and 75,0% of the carcasses with other destinations. Considering the percentile of losses in each category defined by the slaughterhouse visited in this work (non exportable, processed, preserve and grease), this would represent a total loss of 15,58 animals (loss of a total of 18,82% among 86 animals with cannibalism). In the conditions of this study, this would mean that from 5 animals diagnosed with cannibalism in the finishing period, one would be totally wasted at the slaughter time. To this damage must be added the animals that were euthanazied in the herds or those died due to complications of tail injuries. In the present study, an individual diagnosis was performed in the farms of all animals with external lesions suggestive of tail cannibalism and all affected animals were followed at slaughter. Because of this, it was possible to observe that between all animals diagnosed with cannibalism at farm level, only two remained with lesions externally detectable at slaughter, what could be explained by the precocity of the lesions present in the cases analyzed by us. On the other hand, at the slaughter of this group of animals of the cannibalism group but without external lesions at slaughter, a great number of condemnations occurred by abscesses and lung lesions. This suggests that there is a dicotomy between slaughter and field situations, reinforcing the need for a better liaison between these contexts, to be able to adequately assess its impact.

O presente trabalho avaliou a influência de lesões de caudofagia em suínos na terminação sobre o ganho de peso, variáveis sanitárias, ocorrência de lesões e condenações ao abate. O estudo foi realizado em quatro propriedades (PROP) de terminação de suínos. Para cada suíno com lesão de caudofagia foram selecionados dois controles, totalizando a avaliação dos seguintes números de animais: PROP1: 87; PROP2: 33; PROP3: 60; PROP4: 132. As lesões na cauda foram classificadas conforme o grau de severidade (escore de 0 a 4, sendo 0 normal e a severidade aumentando até os graus 2 e 3, e como grau 4 para lesões cicatrizadas). A cada uma de 4 a 6 avaliações (conforme a idade inicial do 1o diagnóstico do problema), os animais eram pesados e as lesões na cauda avaliadas. Em todas as propriedades, foi observada uma recuperação das lesões de caudofagia na terceira avaliação. Nas PROP 1 e 3, animais com lesões de escore 3 (severas) tiveram menor ganho de peso (P<0,05) comparados aos animais de escore 0. Além disso, na PROP3, animais com escore 3 foram menos pesados (P<0,05) ao abate do que aqueles de escore 0. A chance de animais com escore 3 terem artrite e apresentarem nódulos subcutâneos e/ou abscessos foi 25,5 e 30,4 vezes maior, respectivamente, em comparação aos animais com escore 0. Tanto animais com escore 2 (moderado) quanto os com escore 3 apresentaram maiores chances (P<0,05) de terem abscessos ou lesões pulmonares (pleurite e pneumonia embólica) em comparação aos animais sem lesão de cauda. Houve desvio ao Departamento de Inspeção Federal (DIF) de 21,6% (62/287) das carcaças, de animais com lesões e controles, sendo que a caudofagia foi a causa de 66,1% das condenações. Animais com lesões de escore 2 e 3 apresentaram 6,0 e 9,3 vezes maiores chances de terem suas carcaças desviadas ao DIF, respectivamente, comparados aos animais de escore 0. Os animais com lesões de caudofagia representaram 63,0% das carcaças que tiveram destino “não exportável” e 75,0% das carcaças com outros destinos. Considerando os percentuais aproximados de perdas relativas definidas pelo frigorífico visitado para as categorias de condenação (não-exportável, embutido, conserva e graxaria), isto representaria a perda de 15,58 animais (total de 18,12% entre os 86 animais que foram diagnosticados com caudofagia na granja). Isso permite concluir que, nas condições desse estudo, de cada 5 animais que são visualizados com canibalismo na terminação vai ocorrer a perda total de 1 no frigorífico. A esse prejuízo devem ser somados os animais que foram sacrificados nas granjas ou que vieram a morrer devido aos problemas causados pelas complicações das lesões na cauda. No estudo atual, foi possível determinar que, entre todos os que haviam apresentado lesões de canibalismo nas granjas, apenas dois mantinham lesões detectáveis externamente por ocasião do abate, o que pode ser explicado pela ocorrência muito precoce das lesões de caudofagia nos casos observados. Por outro lado, no abate desses animais do grupo com caudofagia, mas sem lesões externas no abate, foi observado um grande número de condenações por abscessos e lesões pulmonares. Isso sugere existir uma dicotomia entre as situações de campo e de frigorífico, reforçando a necessidade de uma melhor ligação entre esses contextos para estimar adequadamente o seu impacto. / The present work assessed the influence of tail biting lesions in finishing pigs in relation to weight gain, health, occurrence of lesions and carcass condemnation at slaughter. The study was carried out in four finishing units (PROP) and the following number of animals were assessed: PROP1: 87; PROP2: 33; PROP3: 60; PROP4: 132. To each animal with tail biting two controls were selected. Tail lesions were classified according the degrees of severity (scores from 0 to 4, 0 classified as normal and severity increasing until the degrees 2 and 3, and degree 4 meaning healed lesions). In each one of 4 to 6 visits (depending on the age of the 1st diagnosis of the problem), the animals were weighed and tail lesions assessed. In all farms, healing of tail lesions was observed in the third evaluation. In PROP 1 and 3, injured animals with score 3 showed smaller weight gain (P<0,05) when compared with animals with score 0. In PROP3, animals with score 3 were lighter (P<0,05) at slaughter than those with score 0. The chance for animals with score 3 to show arthritis and subcutaneous nodules and/or abscesses was 25,5 and 30,4 times higher, respectively, when compared with animals with score 0. Animals with scores 2 (moderate) and 3 (severe) had higher chances (P<0,05) of having abscesses or lung lesions (pleuritis and embolic pneumonia) when compared to animals without tail lesions. Trimming was observed in 21,6% (62/287) of the carcasses of injured and controls, and tail lesions corresponded to 66,1% among condemnations. Animals with lesions of scores 2 and 3 presented 6,0 and 9,3 higher chances of having trimmed carcasses, respectively, when compared with animals with score 0. Animals with tail lesion represented 63,0% of the carcasses with “non exportable” destination and 75,0% of the carcasses with other destinations. Considering the percentile of losses in each category defined by the slaughterhouse visited in this work (non exportable, processed, preserve and grease), this would represent a total loss of 15,58 animals (loss of a total of 18,82% among 86 animals with cannibalism). In the conditions of this study, this would mean that from 5 animals diagnosed with cannibalism in the finishing period, one would be totally wasted at the slaughter time. To this damage must be added the animals that were euthanazied in the herds or those died due to complications of tail injuries. In the present study, an individual diagnosis was performed in the farms of all animals with external lesions suggestive of tail cannibalism and all affected animals were followed at slaughter. Because of this, it was possible to observe that between all animals diagnosed with cannibalism at farm level, only two remained with lesions externally detectable at slaughter, what could be explained by the precocity of the lesions present in the cases analyzed by us. On the other hand, at the slaughter of this group of animals of the cannibalism group but without external lesions at slaughter, a great number of condemnations occurred by abscesses and lung lesions. This suggests that there is a dicotomy between slaughter and field situations, reinforcing the need for a better liaison between these contexts, to be able to adequately assess its impact.