Papers by Alfredo Pereira
Nellore cattle is well adapted to tropical environmental conditions with good thermoregulatory ch... more Nellore cattle is well adapted to tropical environmental conditions with good thermoregulatory characteristics. However, knowledge related to body temperature regulation and acclimatization mechanisms are still scarce. This investigation aimed to understand the heat loss efficiency and thermoregulation responses of Nellore cows in tropical climate conditions. In this study was used 16 healthy purebred Nellore cows classified by heat loss in efficient and non-efficient using the vaginal temperature continuously monitored by data-loggers. The rectal, tail and ocular temperatures, sweating rate and respiratory frequency were also measured to understand the thermoregulatory responses and correlate to previous classification. In our findings, were noticed that according to heat loss classification the non-efficient cows showed greater amplitude of temperature variation. The body temperature increased from 12:00 PM to 19:00 PM with gradual decreased from 19:00 PM to 07:00 AM, reaching the...
Journal of Thermal Biology
The frequency of heat waves has increased over the last years, with an impact on animal productio... more The frequency of heat waves has increased over the last years, with an impact on animal production and health, including the death of animals. Therefore, the aim of this study was to evaluate the dynamics of thermoregulation and hormonal responses in non-pregnant and pregnant ewes exposed to successive heat waves. Twentyfour non-pregnant and 18 pregnant Santa Ines ewes with black coat color (live weight: 55 ± 9.03 kg; age: 60 months) were used. Weather variables such air temperature, relative humidity, and solar radiation were continuously recorded. The rectal and tympanic temperatures and respiratory rate were measured daily. Serum triiodothyronine (T3) and prolactin were evaluated during the heat wave and thermoneutral periods. The physiological variables were higher under the heat wave conditions and were related to the activation of the thermoregulatory system for maintaining homeothermy (P < 0.05). The core body temperature was higher during successive heat waves (P < 0.05), as was the tympanic temperature, which are both affected by changes in air temperature (P < 0.05). T3 and prolactin levels were not influenced by successive heat waves (P < 0.05) and rectal temperature and respiratory rate were highest in non-pregnant ewes (P < 0.05). Prolactin was not affected by temperature. The results indicate that the Santa Ines breed overcomes the thermal challenge during a heat wave without showing severe signs of thermal stress regardless of being pregnant or not.
Zootecnia: Desafios e tendências da ciência e tecnologia
Editora Direitos para esta edição cedidos à Atena Editora pelos autores. Open access publication ... more Editora Direitos para esta edição cedidos à Atena Editora pelos autores. Open access publication by Atena Editora Todo o conteúdo deste livro está licenciado sob uma Licença de Atribuição Creative Commons. Atribuição-Não-Comercial-NãoDerivativos 4.0 Internacional (CC BY-NC-ND 4.0). O conteúdo dos artigos e seus dados em sua forma, correção e confiabilidade são de responsabilidade exclusiva dos autores, inclusive não representam necessariamente a posição oficial da Atena Editora. Permitido o download da obra e o compartilhamento desde que sejam atribuídos créditos aos autores, mas sem a possibilidade de alterála de nenhuma forma ou utilizá-la para fins comerciais. Todos os manuscritos foram previamente submetidos à avaliação cega pelos pares, membros do Conselho Editorial desta Editora, tendo sido aprovados para a publicação com base em critérios de neutralidade e imparcialidade acadêmica. A Atena Editora é comprometida em garantir a integridade editorial em todas as etapas do processo de publicação, evitando plágio, dados ou resultados fraudulentos e impedindo que interesses financeiros comprometam os padrões éticos da publicação. Situações suspeitas de má conduta científica serão investigadas sob o mais alto padrão de rigor acadêmico e ético.
The work aims to analize the behavior response and the ability to cope stressors when the piglets... more The work aims to analize the behavior response and the ability to cope stressors when the piglets are exposed to aggressive treatment during the lactation phase. The behavior of 40 piglets was observed from birth to weaning (28 days). In the first fifteen days the observations were done every three days, with an interval of another three days. After this period, the observations were done once a week. Over a period of three hours, every five minutes it was registered the animal behavior. The group was divided into two treatments: rational group, where 18 piglets had minimal interaction with people and it was permitted the routine practice without sudden movements and loud sounds; and the aversive treatment, where 22 piglets received the daily routine of the farm, however, on every half hour during observations the observer performed a direct threat to the sow going into the cage with a flag and abruptly approach the animal, shouting or clapping. To avoid visual contact with the obs...
Pesquisa Veterinária Brasileira, 2017
RESUMO: Desmama é uma fase crítica na vida do suíno devido a separação materna e a introdução de ... more RESUMO: Desmama é uma fase crítica na vida do suíno devido a separação materna e a introdução de uma dieta seca. A termografia infravermelha medida na região ocular se mostra como um indicador confiável para a condição de estresse pontual de suínos. O objetivo deste estudo foi determinar a relação entre medidas de termografia infravermelha da superfície ocular e de cortisol em situações de estresse em leitões na pós desmama. Foram avaliados 66 leitões, uma vez por semana, durante sete semanas, em dois períodos do dia (7h e 15h) com medidas de temperatura superficial ocular, temperatura superficial do dorso e amostras de saliva para determinação de cortisol salivar. A análise estatística contemplou os efeitos fixos de semana e período do dia e sua interação e correlações de Pearson para relação entre termografia ocular, temperatura superficial e cortisol a 5% de significância. Cortisol salivar não diferiu entre os períodos, mas foi superior nas três primeiras semanas após o desmame (...
The work aims to determine thermolysis capacity by losses by sweating using trans epidermal water... more The work aims to determine thermolysis capacity by losses by sweating using trans epidermal water loss values (TEWL) and by tachypnea. Fifty six Santa Ines ewes were divided in facilities having covered area with a cement floor and fiber cement roof panels (4 m high, 8 x 10 m) and uncovered area with hard dirt floor (15 x 15 m). Thermolysis capacity was evaluated using heat stress challenge in three consecutive days, in which animals stayed under the shade, from 08:00 to 13:00 h, when the first sample was taken (T0: 08:00 h). From 13:00 to 14:00 h, they stayed in sunny place for 1 h, and the second sample was taken (T1: 14:00h). Then, animals went back to the shade, where they stayed for more 45 minutes (14:00–14:45 h), and the third sample was taken (T2: 14:45h). TEWL with a VapoMeter (Delfin, Finland), respiratory rate (RR) by count of movements per minute and rectal temperature (RT) with a digital thermometer were collected in all sampling times. During the heat challenge, air tempe...
It is evident the necessity of a better understanding regarding the influence of warmth on the pe... more It is evident the necessity of a better understanding regarding the influence of warmth on the performance of horses in training, establishing that an efficient thermoregulation is essential to provide the physiological demands resulting from effort required and the climatic variables which the animal is exposed. This study aimed to evaluate thermoregulation in horses subjected to 30 minutes of exercise during three periods of the day with different air temperatures and to compare two techniques for measuring the sweating rate (SR) and trans epidermal water loss (TEWL). Three castrated crossbred horses were submitted to a series of half an hour of exercise at different moments (07:00, 13:00, 16:00 hours), carried out as follows: 3 minutes walking, 3 minutes of canter, 10 minutes of trot, 10 minutes of canter, 2 minutes of trot and 2 minutes of canter. Relative humidity, black globe and air temperature were 50%, 34Co and 20.8oC; 62%, 35oC and 28.8Co; 48%, 34.5Co and 27.4Co; respectiv...
Journal of Animal Behaviour and Biometeorology, 2018
This study investigates the combined effect of the progressive or abrupt weaning after the stress... more This study investigates the combined effect of the progressive or abrupt weaning after the stress during middle and late pregnancy on performance and development of lambs. Twenty-four male lambs were used, born from 18 Santa Ines ewes that were divided into three experimental groups. Pregnant ewes were submitted to the application of Lipolysaccharides E. coli (LPS) during the 70 th day of pregnancy (Ig; n=12) or at the 120 th day (Fg; n=8). Animals were kept as control (Cg; n=14). Lambs born in a 6 day interval were subjected to two types of weaning (Pw: progressive weaning; Aw: abrupt weaning at 45 days of age). Lamb data, including testicular development, yield carcass and economic cost were analyzed. Means were compared by F test and Student's t test (P<0.05). Fg lambs had the lowest average carcass weight compared with Cg and Fg groups (P<0.05) and lambs from progressive weaning had higher carcass weight in relation to the abrupt weaning process (P<0.05). On carcass yield, no difference was observed on gestation groups for any type of weaning (P>0.05). The highest yields in gross margin was observed for the Cg group and the lowest for Fg (P<0.05), and no difference to Ig group (P>0.05). On lambs' testicular weight, Cg average value was higher than Fg (P<0.05), but no difference was observed on scrotal circumference (P>0.05). The combined effect of LPS challenge as a simulated disease process during late pregnancy and abrupt weaning change the testicular weight and the yield carcass, resulting in economic losses.
This experiment was developed in three stages with 12 adults female Merino sheep, six white and s... more This experiment was developed in three stages with 12 adults female Merino sheep, six white and six black, aiming at evaluating the differences between these breeds sheep concerning: I. Index of tolerance to heat, II. Thermic balance and heat stock circadian variation, and; III. Adaptive behavior. In the tolerance to heat, the superior stock displayed by the rectal temperatures of black sheep during their stay in the sun was worthy of notice. However, it has fast but incomplete recovery after being exposed to one hour of shade. In the same study, the sweat rates of the black sheep surpassed those of the White ones, that is, after the recovery in the shade. On circadian cycles in shade evaluations, the superiority of rectal temperatures for White sheep deserves to be highlighted. In addition, the sweat rates of the black ones surpassed those of the White ones at the hottest hours. Concerning behavior, it was also possible to notice some differences between the breeds studied here. Among them, we can highlight the superiority in terms of grazing time of White sheep. Differences between the two studied colors of Merino breed occur in the thermic balance as well as in the thermoregulating answers
ACADEMIC RESEARCH ON CATTLE’S ACCLIMATISATION PROCESS Flávio Silva1, Cristina Conceição1,2, Lilia... more ACADEMIC RESEARCH ON CATTLE’S ACCLIMATISATION PROCESS Flávio Silva1, Cristina Conceição1,2, Liliana Cachucho3, Catarina Matos1, Ana Lúcia Garrido1, Ana Geraldo1,2, Elsa Lamy2, Fernando Capela e Silva2,4, Paulo Infante5 & Alfredo Pereira1,2, 1Departamento de Zootecnia, Universidade de Évora, Portugal; 2ICAAM, Universidade de Évora, Portugal; 3CEBAL, Beja, Portugal; 4Departamento de Biologia, Universidade de Évora, Portugal; 5Deparatamento de Matemática, Universidade de Évora, Portugal. ABSTRACT Animal’s welfare and performance is compromised by environmental heat stress, present during summer in the Mediterranean climate. Heat stress effects are well known and widely studied, although the mechanisms of season acclimatisation are less well understood. Throughout the last 20 years, we have been studying this process in the Mediterranean and tropical regions, aiming to understand it better, developing and improving methodologies and search for reliable biomarkers of thermal stress. The ...
O teste de novos biomateriais para aplicações clínicas em ortopedia, ou noutras áreas da medicina... more O teste de novos biomateriais para aplicações clínicas em ortopedia, ou noutras áreas da medicina, em modelos animais vivos e sencientes, em prol do benefício humano, deve ser objecto de planeamento cuidado e ponderado, dado o conflito ético que se coloca. Compete-nos, enquanto investigadores, garantir que as condições de vida, saúde e bem-estar são asseguradas. O uso de ovinos como modelo superior pré-clínico, para investigação em Ortopedia, tem-se evidenciado devido às suas características translacionais para a espécie humana. Neste estudo retrospectivo deu-se ênfase ao plano anestésico/ analgésico instituído em três tipos de técnicas cirúrgicas ortopédicas, realizadas em ovinos. Os animais intervencionados foram adquiridos com 2 meses de antecedência em relação às cirurgias e mantidos em rebanho, com condições adequadas de abrigo, alimentação e maneio. As técnicas cirúrgicas inovadoras foram treinadas previamente em peças anatómicas adquiridas no matadouro. Todas as cirurgias e a...
International Journal of Remote Sensing, 2017
ABSTRACT Montado is a silvo-pastoral ecosystem of the Mediterranean region, a mixed system of tre... more ABSTRACT Montado is a silvo-pastoral ecosystem of the Mediterranean region, a mixed system of trees and pasture, subject to animal grazing. Farmers need information on pasture production and quality in order to assess the direct effect of tree presence on the productivity of their pastoral system, and to devise management that balances farm production and profitability with sustainable soil management. The main objectives of this work were (1) to evaluate tree influence on soil and pasture parameters and (2) to evaluate the use of proximal sensing techniques that have potential for monitoring aspects related to spatial and temporal variability of pasture productivity and quality in montado ecosystems. Both objectives can support the decision-making process of the farmer. The study field is located in Mitra farm, in Southern Portugal. During October 2015, 24 geo-referenced composite soil samples (12 under tree canopy and 12 outside tree canopy) were collected from the 0.0–0.3 m soil layer. The soil samples were analysed for texture (sand, silt, and clay content), moisture content, pH, organic matter, total nitrogen (N), phosphorus (P), potassium (K), magnesium (Mg), and manganese (Mn). The evolution of the pasture was recorded in the 24 sampling points at five monitoring dates: at the end of autumn (December 2015), at the end of winter (March 2016), and then monthly during spring 2016 (April, May, and June). The following pasture parameters were measured: normalized difference vegetation index (NDVI), capacitance, temperature, green and dry matter, ash, crude protein (CP), and neutral detergent fibre. Soil under tree canopy had significantly higher levels of organic matter, N, P, K, and Mg, and better pasture quality while the pasture productivity was higher outside tree canopy. The correlation between pasture direct measurements and sensor parameters was more consistent between capacitance and pasture productivity and between NDVI and CP. The use of fast and efficient tools associated with geo-referenced systems can greatly simplify the pasture monitoring process, which is the basis for estimating feed availability in the field. The knowledge of biomass quality and quantity is fundamental to support decision-making regarding animal stocking rates and rotation among grazing parcels.
International journal of biometeorology, Jan 16, 2018
Adaptation is a relevant characteristic to be understood in livestock animals in order to maintai... more Adaptation is a relevant characteristic to be understood in livestock animals in order to maintain and raise productivity. In Brazil, the Nellore beef cattle are widely disseminated and well-adapted breed that present good thermoregulatory characteristics for tropical environment conditions. Conversely, the physiological and cellular mechanisms required for thermoregulation and thermotolerance in this breed are still limited. The aim of this study was to comprehend the heat loss efficiency at the whole animal level and heat shock response at the cellular level of Nellore cows in tropical climate conditions. Healthy purebred Nellore cows were classified according to their capacity to lose body heat as Efficient or Inefficient based on vaginal temperature which was continuously monitored by data-loggers. Rectal, tail, and ocular temperatures, sweating rate, and respiratory frequency were collected to assess other thermoregulatory responses. Peripheral mononuclear cells were used for g...
Revista de Ciências Agrárias, 2016
As pastagens naturais e biodiversas que suportam a pecuária extensiva são caracterizadas por marc... more As pastagens naturais e biodiversas que suportam a pecuária extensiva são caracterizadas por marcada variação da biomassa das espécies botânicas presentes, e do seu estado fenológico ao longo das estações do ano. Nestas circunstâncias, a utilização do alimento e a ocupação do espaço da pastagem podem ser muito heterogéneas devido, entre outras causas, ao comportamento de pastoreio dos ruminantes. Uma gestão eficiente do pastoreio exige conhecimento sobre o mecanismo de ajuste do comportamento de pastoreio à pastagem. Embora exista tecnologia GNSS que possibilita a monitorização do comportamento de pastoreio, o seu custo de aquisição é elevado, limitando a sua aplicação aos estudos de investigação. O presente trabalho revê os princípios que permitem a aplicação desta tecnologia e tem por objectivo estudar a utilização de recetores GNSS comerciais de baixo custo ("commercial of the shelf-COTS": CatTrack TM). Foram utilizados seis recetores, durante seis períodos de recolha de dados, ao longo de dois meses de pastoreio contínuo de uma pastagem natural, tendo sido a exactidão dos recetores de 14m e de 40m em testes estáticos e dinâmicos, respectivamente, a precisão de 3m e a fiabilidade de 80%. O equipamento testado permitiu diferenciar as actividades dos animais (pastoreio, repouso e trânsito), determinar a localização de ovinos em pastoreio, e caracterizar padrões, percursos e zonas preferenciais. Conclui-se que o equipamento COTS apresenta uma elevada relação qualidade/preço, pelo que pode vir a ser uma ferramenta importante para suporte das decisões que são essenciais a um maneio mais preciso da pastagem. Palavras-chave: comportamento de pastoreio, maneio de pastagens, pecuária de precisão, rastreamento de animais, recetores de GPS A B S T R A C T Extensive livestock production is supported by natural and biodiverse pastures, characterized by marked seasonal variation of biomass, plant species and growth stage. The use of the food resources and the occupation of grazing space can be very heterogeneous in such conditions due to ruminants grazing behaviour. Successful grazing and pasture management requires an understanding of the adjustment mechanisms behind the grazing behaviour that enables adaptation to grazing conditions. Use of GNSS technology allows a quick and effective grazing data collection which is, however expensive, limiting its application to research purposes. This paper reviews the principles for the application of GNSS technology and evaluates the use of inexpensive commercial GNSS receivers (commercial of the shelf-COTS: CatTrack TM "). Six receivers were used for six data collection period over two months of continuous grazing on a natural pasture. The measured static and dynamic accuracy of the receivers is 14m and 40m, respectively. The precision was 3m and the reliability 80%. The tested equipment allows the differentiation between animal activities (grazing, resting and transit). It also determines sheep locations, allowing the characterization of patterns, pathways and preferred areas. It is concluded that the COTS equipment has a high quality / price ratio, so it can become an important support decision tool essential to a more precise pasture management.
The Spine Journal, 2016
This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 Intern... more This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International licence Newcastle University ePrints-eprint.ncl.ac.uk
Os búfalos são particularmente intolerantes à radiação solar direta. Durante os períodos quentes ... more Os búfalos são particularmente intolerantes à radiação solar direta. Durante os períodos quentes do dia, os animais tendem a procurar poças de água ou lama para se refrescarem e usualmente pastejam apenas nas horas de menor temperatura. O presente trabalho propõe estudar soluções de manejo possíveis ao bubalinocultor através de respostas comportamentais. O ensaio utilizou dez búfalas de 24 meses, observadas por três dias (das seis às dezoito horas) em cada sistema de manejo a pasto: com sombra natural e artificial (S); com sombra artificial e água para imersão (SA); com água para imersão (A), quanto à sua posição (sol, sombra, água), postura (em pé ou deitado) e atividade (pastando, ruminando etc.). Os animais passaram mais de 60% do tempo ao sol (S: 63,9%, SA: 64,5%, A: 71,9%), mormente pastejando. Na sombra e na água os principais comportamentos foram ruminação e ócio. O uso da água foi notadamente preferencial (SA: 237,7 minutos, A: 205,1 minutos). Os resultados revelam a necessidade do uso de recursos de proteção contra a radiação solar para búfalos em dias quentes e que, quando disponível, a oferta de água para imersão deve ser priorizada.
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Papers by Alfredo Pereira