RESUMO

Is well known the taurine and zebuine susceptibility to Rhipicephalus microplus. Few are the reports regarding tick population dynamics between the same herd/breed, and because of this, two experiments were performed. In the 1st, the cattle tick population dynamics in dairy nursing calves (reared collective and individually), weaning calves (4-16 months), heifers (17-29 months), cows in lactation and dry cows (≥ 30 months) from the same herd, tick burden and milk production correlation were performed, for two years. R. microplus females (4.5-8.0 mm) counts and the milk production were performed every 28 and 14 days, respectively. In the 2nd experiment, bovines belonging to different categories/age (newborn without previous contact with tick; 12-13 months with tick contact since birth; and 23-24 months with tick contact since birth) were experimentally infested with 30,000 R. microplus larvae, to quantify the number of fully engorged females detached from these animals. In the 1st experiment, when the mean counts of tick were ≥ 30 all animals of the group were treated. Nursing calves showed 3-4 peaks of ticks, animals reared individually showed smaller (p ≤ 0.05) tick burden than those reared collectively. Weaning calves (4-8 months) showed 5 tick peaks/year and higher mean tick burden was found than other categories. On the other hand, animals with 17-29 months of age showed smallest (p ≤ 0.05) tick burden, with 3 tick peaks/year. When the animal become lactating the tick burden increase, and 5 peaks/year occurred, and decrease again in dry cows (p ≤ 0.05) showing 4-5 tick peaks/year. Weaning calves and lactating cows received more acaricide treatments (p ≤ 0.05), 18 and 15, respectively. Nursing calves reared individually, and heifers (21-29 months) were the categories that received two acaricide treatments. The more milk the cow produce, more ticks it has (p ≤ 0.05). In the 2nd experiment, more (p ≤ 0.05) fully engorged females were recovered from younger animals than older ones. So, different tick control strategies need to be adopted in different dairy cattle categories, and the tick burden should be considered, once the effect may be more inherent to the animal rather than the strategy adopted.

Assuntos

RESUMO

The development of a strategic protocol is fundamental to the control of Rhipicephalus microplus. The efficacy of different strategic tick control protocols (Day 1 to Day 119) using commercial acaricides according to R. microplus burden on bovines was evaluated. Female ticks (4.5-8 mm in length) were initially counted on cattle to form four groups of bovines with low and high tick burdens (treated and control), with 10 animals each. The animals were then (Day 0) kept in different paddocks, and the bovines from the two treated groups received their first treatment. The main difference in the protocols was the use of a spray formulation on animals with high tick burden. Additionally, the criterion for animal re-treatment (treatment interval) during the proposed strategic protocol was evaluated according to tick length by visual inspection - if 30% of the bovines of a group presented ticks < 4 mm between their legs and dewlap, the treatment was applied, which could change the originally proposed intervals. The number of days for which animals from the treated groups remained without acaricide administration (palliative control, ≥30 tick females < 4 mm) after the end of the strategic tick control protocol was recorded. Tick counts and visual inspection were done weekly until days 203 and 119, respectively. The results showed that the adopted protocol was successful based on calculated efficacy. Mean efficacies from Day 7 to Day 119 were 86.1% and 96.1% for treated groups with low and high tick burdens, respectively, and mean tick count did not differ between them (P > 0.05) but did differ from their respectively controls (P = <0.0001). The use of spray formulation at the beginning of the protocol for animals with a high tick burden helped to avoid harmful tick infestations. Visual analysis of tick length anticipated the proposed treatment intervals. Treated groups remained without palliative treatment for 70 days, while control groups needed treatment every 28 days. It was concluded that strategic control protocols must be developed according to tick burden, and tick length can be used to indicate when treatment needs to be applied.

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RESUMO

The aim of this study was to examine the behavioral, productive, reproductive and thermoregulatory performance of ¾ and ⅞ Holstein/Gir (HG) dairy cows to identify which genetic composition suffers the least heat stress. A completely randomized design was adopted involving 20 multiparous, lactating crossbred cows from a dairy farm located in the municipality of Turvânia - GO, Brazil. During the experimental period, data on behavioral, productive, reproductive and thermoregulatory traits were collected every 15 days. Bioestat (5.0) statistical software was used for statistical analysis. The mean temperature-humidity index, ambient temperature and relative humidity obtained throughout the experimental period were 74.45, 30.51 ºC and 63.64%, respectively. In terms of reproductive performance, there was a significant difference (p < 0.05) between the genetic compositions for the time from calving to first service, with a longer period shown by the animals with greater Holstein breed genetic composition. Service period and calving interval differed significantly (p < 0.05) during the experimental period between the genetic compositions. A significant difference (p < 0.05) was also detected between the compositions for respiratory rate, with higher values observed in the animals with higher European genetic composition. Benezra thermal comfort index also differed significantly (p < 0.05), with the ⅞ HG animals showing a higher value. Lactating cows with a ⅞ HG genetic composition achieved better results in milk production, whereas those with ¾ HG genetic composition showed superiority in milk fat composition and reproductive and thermoregulatory performance, indicating greater adaptation to the climatic conditions of the region.(AU)

Objetivou-se avaliar o desempenho comportamental, produtivo, reprodutivo e termorregulador de vacas leiteiras ¾ e ⅞ Holandês/Gir (HG), com intuito de identificar qual composição genética sofre menor estresse térmico pelo calor. Foi utilizado um delineamento inteiramente casualizados com 20 vacas mestiças, em lactação, multíparas, pertencentes à propriedade leiteira localizada no município de Turvânia, GO. Durante o período experimental, a cada 15 dias foram coletados dados das características comportamentais, produtivas, reprodutivas e termorreguladoras. Para a realização das análises estatísticas foi utilizado o programa estatístico Bioestat (5.0). Os valores médios obtidos durante todo o período experimental para índice de temperatura e umidade, temperatura ambiente e umidade relativa do ar foram 74,45, 30,51ºC e 63,64%, respectivamente. Quanto ao desempenho reprodutivo, houve diferença significativa (p < 0,05) entre as composições genéticas para o intervalo do parto ao primeiro serviço, observando valor maior para os animais com maior composição genética da raça Holandesa. Para as características período de serviço e intervalo de parto foram constatadas diferenças significativas (p < 0,05) durante o período experimental entre as composições genéticas. Foi encontrado diferença significativa (p < 0,05) entre as composições na característica de frequência respiratória, observando-se maior frequência para os animais com maior composição genética europeia. Foi observado diferença significativa (p < 0,05) na característica índice de conforto de Benezra, onde foi encontrado maior valor para a composição genética ⅞ HG. As vacas em lactação com composição genética ⅞ HG obtiveram melhores resultados na produção de leite, mas em contrapartida a composição genética ¾ HG mostraram superioridade na composição de gordura do leite e no desempenho reprodutivo e termorregulador, evidenciando maior adaptação as condições climáticas da região.(AU)

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RESUMO

Artificial shading is widely used to provide thermal comfort to animals and has been extensively researched due to its relationship with their welfare and performance. This study examines the physiological and behavioral traits of sheep in a feedlot system with and without access to shade. Twenty male Santa Inês × Dorper crossbred sheep with an initial average weight of 25 kg were used in the experiment. The animals were kept in two collective stalls, one of which was equipped with a polypropylene mesh shade net with 80% light interception capacity. The experiment was conducted in the feedlot of the Fazenda Escola farm at UEG, São Luís de Montes Belos Campus, state of Goiás, Brazil. Environmental indices (ambient temperature, relative humidity, temperature-humidity index), respiratory rate (RR), rectal temperature (RT) and surface temperature (ST) were measured once weekly and behavioral assessments were performed one day after the physiological assessment, between 07h00 and 19h00. The following behaviors were evaluated: feeding, rumination, rest/sleep, social, play and anomalous activities. There were no significant differences for the analyzed variables and treatments. Animals with access to shade had the following physiological results: RR - 75.06 mov. min-¹; ST - 33.03 ºC; and RT - 39.21 ºC. Those without access to shade, in turn, showed the following indices: RR - 81.52 mov. min-¹; ST - 33.45 ºC; and RT - 39.43 ºC. The evaluated behaviors did not differ significantly, averaging 226.11 and 225.44 min (feeding), 153.33 and 149.44 min (rumination), 341.39 and 339.72 min (rest/sleep) and 152.50 and 154.72 min (other activities) recorded in the sheep with and without access to shade, respectively. Despite the lack of differences between the analyzed responses, the animals with access to artificial shade showed greater comfort, welfare and quality of life.(AU)

O sombreamento artificial é muito utilizado para proporcionar conforto térmico aos animais, e tem sido muito estudado em função da sua relação com o bem-estar e desempenho dos mesmos. Objetivou-se avaliar as características fisiológicas e comportamentais de ovinos em sistema de confinamento com e sem acesso a sombra. Foram avaliados 20 ovinos machos mestiços Santa Inês x Dorper com peso médio inicial de 25 Kg, mantidos em duas baias coletivas, com implantação do sombrite de malha de polipropileno, 80% de interceptação luminosa em uma das baias. O experimento foi conduzido no confinamento da Fazenda Escola da UEG, Campus São Luís de Montes Belos, Goiás, Brasil. Avaliações ambientais, temperatura ambiente (TA), umidade relativa do ar (UR), índice de temperatura e umidade (ITU), frequência respiratória (FR) e de superfície (TS) foram realizadas uma vez por semana e avaliações de comportamento foram realizadas um dia após a avaliação fisiológica, entre 7h e 19h. Os comportamentos avaliados foram o alimentar, ruminação, descanso e sono, social, lúdico e anormal. Em relação aos resultados obtidos, não apresentaram diferença significativa em relação as variáveis e tratamentos analisados. Os animais com acesso a sombra apresentaram em relação à FR, TS e TR, valores de 75,06 mov. min-¹, 33,03ºC e 39,21ºC, respectivamente, enquanto os animais sem acesso ao sombreamento apresentaram 81,52 mov. min-¹, 33,45ºC de TS e 39,43ºC de TC. Os comportamentos avaliados não diferiram significativamente, com médias em minutos para os comportamentos alimentar de 226,11 e 225,44, ruminação de 153,33 e 149,44, descanso e sono de 341,39 e 339,72 e outras atividades de 152,50 e 154,72, para os animais com e sem acesso ao sombreamento, respectivamente. Apesar de não observar diferenças entre as respostas analisadas, pode-se observar um maior conforto, bem-estar e qualidade de vida para os animais com acesso ao sombreamento artificial.(AU)

Assuntos

RESUMO

Artificial shading is widely used to provide thermal comfort to animals and has been extensively researched due to its relationship with their welfare and performance. This study examines the physiological and behavioral traits of sheep in a feedlot system with and without access to shade. Twenty male Santa Inês × Dorper crossbred sheep with an initial average weight of 25 kg were used in the experiment. The animals were kept in two collective stalls, one of which was equipped with a polypropylene mesh shade net with 80% light interception capacity. The experiment was conducted in the feedlot of the Fazenda Escola farm at UEG, São Luís de Montes Belos Campus, state of Goiás, Brazil. Environmental indices (ambient temperature, relative humidity, temperature-humidity index), respiratory rate (RR), rectal temperature (RT) and surface temperature (ST) were measured once weekly and behavioral assessments were performed one day after the physiological assessment, between 07h00 and 19h00. The following behaviors were evaluated: feeding, rumination, rest/sleep, social, play and anomalous activities. There were no significant differences for the analyzed variables and treatments. Animals with access to shade had the following physiological results: RR - 75.06 mov. min-¹; ST - 33.03 ºC; and RT - 39.21 ºC. Those without access to shade, in turn, showed the following indices: RR - 81.52 mov. min-¹; ST - 33.45 ºC; and RT - 39.43 ºC. The evaluated behaviors did not differ significantly, averaging 226.11 and 225.44 min (feeding), 153.33 and 149.44 min (rumination), 341.39 and 339.72 min (rest/sleep) and 152.50 and 154.72 min (other activities) recorded in the sheep with and without access to shade, respectively. Despite the lack of differences between the analyzed responses, the animals with access to artificial shade showed greater comfort, welfare and quality of life.

O sombreamento artificial é muito utilizado para proporcionar conforto térmico aos animais, e tem sido muito estudado em função da sua relação com o bem-estar e desempenho dos mesmos. Objetivou-se avaliar as características fisiológicas e comportamentais de ovinos em sistema de confinamento com e sem acesso a sombra. Foram avaliados 20 ovinos machos mestiços Santa Inês x Dorper com peso médio inicial de 25 Kg, mantidos em duas baias coletivas, com implantação do sombrite de malha de polipropileno, 80% de interceptação luminosa em uma das baias. O experimento foi conduzido no confinamento da Fazenda Escola da UEG, Campus São Luís de Montes Belos, Goiás, Brasil. Avaliações ambientais, temperatura ambiente (TA), umidade relativa do ar (UR), índice de temperatura e umidade (ITU), frequência respiratória (FR) e de superfície (TS) foram realizadas uma vez por semana e avaliações de comportamento foram realizadas um dia após a avaliação fisiológica, entre 7h e 19h. Os comportamentos avaliados foram o alimentar, ruminação, descanso e sono, social, lúdico e anormal. Em relação aos resultados obtidos, não apresentaram diferença significativa em relação as variáveis e tratamentos analisados. Os animais com acesso a sombra apresentaram em relação à FR, TS e TR, valores de 75,06 mov. min-¹, 33,03ºC e 39,21ºC, respectivamente, enquanto os animais sem acesso ao sombreamento apresentaram 81,52 mov. min-¹, 33,45ºC de TS e 39,43ºC de TC. Os comportamentos avaliados não diferiram significativamente, com médias em minutos para os comportamentos alimentar de 226,11 e 225,44, ruminação de 153,33 e 149,44, descanso e sono de 341,39 e 339,72 e outras atividades de 152,50 e 154,72, para os animais com e sem acesso ao sombreamento, respectivamente. Apesar de não observar diferenças entre as respostas analisadas, pode-se observar um maior conforto, bem-estar e qualidade de vida para os animais com acesso ao sombreamento artificial.

Assuntos