The frequent detection of a treponeme in bovine digital dermatitis by immunocytochemistry and polymerase chain reaction

A study was carried out to determine whether spirochaetes are frequently associated with digital dermatitis in United Kingdom (UK) dairy cattle. Histopathological examination of lesions using a silver stain showed a large number of unidentified spirochaete-like organisms present in digital dermatitis hoof skin tissue in all examined biopsies. Immunocytochemical staining demonstrated that spirochaetes in skin lesions were identified by polyclonal antisera to Borrelia burgdorferi, Treponema denticola and Treponema vincentii (again all biopsies were positively stained), whereas monoclonal antibodies to B. burgdorferi and any Treponema pallidum did not stain any organisms in all biopsies. A PCR of 16S rRNA, previously shown to be specific for a new treponeme, was employed and produced positive results from 82.4% of digital dermatitis tissues. It is concluded that this spirochaete (or related spirochaetes), which is similar to human oral treponemes, is frequently associated with, and may be responsible for, pathological changes in digital dermatitis. (C) 1998 Elsevier Science B.V.

Heat tolerance and the effects of shade on the behavior of Simmental bulls on pasture

The objectives were to assess the degree of thermolysis capacity as a characteristic of heat tolerance of the Simmental beef cattle and evaluate the effects of shade and shade type (artificial: AS, trees: TS, or no shade: NS) on daily behavior patterns during summer. Black globe temperature (BGT) was different under the two types of shade (P < 0.05) and was lower under the TS (P < 0.01) and under AS (P > 0.01) than average BGT in the sun. Animals when in AS used more intensely the shade (P = 0.002) mostly lying down under it (10.00-14.00 hours), while time standing was similar (P = 0.107) between TS and NS. Bulls without shade (NS) spent significantly more time at the water trough and most part of the day standing idle (72.4%, 10.1 h/14 h). TS bulls spent more time grazing/standing (P < 0.001). The Simmental bulls that were in TS and AS spent more time ruminating than bulls that stay without shade (NS). The availability of shade changes grazing, rumination and idling behavior of cattle in response to environmental conditions. Shade provided by trees can be more efficient than artificial shading as cattle spent more time grazing when tree shade was available. Thermolysis capacity can be used to select heat-tolerant animals.

Assessment of DGAT1 and LEP gene polymorphisms in three Nelore (Bos indicus) lines selected for growth and their relationship with growth and carcass traits

The aim of this study was to analyze LEP and DGAT1 gene polymorphisms in 3 Nelore lines selected for growth and to evaluate their effects on growth and carcass traits. Traits analyzed were birth, weaning, and yearling weight, rump height, LM area, backfat thickness, and rump fat thickness obtained by ultrasound. Two SNP in the LEP gene [LEP 1620(A/G) and LEP 305(T/C)] and the K232A mutation in the DGAT1 gene were analyzed. The sample consisted of 357 Nelore heifers from 2 lines selected for yearling weight and a control line, established in 1980, at the Estacao Experimental de Zootecnia de Sertaozinho (Sertaozinho, Brazil). Three genotypes were obtained for each marker. Differences in allele frequencies among the 3 lines were only observed for the DGAT1 K232A polymorphism, with the frequency of the A allele being greater in the control line than in the selected lines. The DGAT1 K232A mutation was associated only with rump height, whereas LEP 1620(A/G) was associated with weaning weight and LEP 305(T/C) with birth weight and backfat thickness. However, more studies, with larger data sets, are necessary before these makers can be used for marker-assisted selection.

Intake, water consumption, ruminal fermentation, and stress response of beef heifers fed after different lengths of delays in the daily feed delivery time

Four rumen-fistulated Holstein heifers (134 +/- 1 kg initial BW) were used in a 4 x 4 Latin square design to determine the effects of delaying daily feed delivery time on intake, ruminal fermentation, behavior, and stress response. Each 3-wk experimental period was preceded by 1 wk in which all animals were fed at 0800 h. Feed bunks were cleaned at 0745 h and feed offered at 0800 h (T0, no delay), 0900 (T1), 1000 (T2), and 1100 (T3) from d1 to 21 with measurements taken during wk 1 and 3. Heifers were able to see each other at all times. Concentrate and barley straw were offered in separate compartments of the feed bunks, once daily and for ad libitum intake. Ruminal pH and saliva cortisol concentrations were measured at 0, 4, 8, and 12 h postfeeding on d 3 and 17 of each experimental period. Fecal glucocorticoid metabolites were measured on d 17. Increasing length of delay in daily feed delivery time resulted in a quadratic response in concentrate DMI (low in T1 and T2; P = 0.002), whereas straw DMI was greatest in T1 and T3 (cubic P = 0.03). Treatments affected the distribution of DMI within the day with a linear decrease observed between 0800 and 1200 h but a linear increase during nighttimes (2000 to 0800 h), whereas T1 and T2 had reduced DMI between 1200 and 1600 h (quadratic P = 0.04). Water consumption (L/d) was not affected but decreased linearly when expressed as liters per kilogram of DMI (P = 0.01). Meal length was greatest and eating rate slowest in T1 and T2 (quadratic P <= 0.001). Size of the first meal after feed delivery was reduced in T1 on d 1 (cubic P = 0.05) and decreased linearly on d 2 (P = 0.01) after change. Concentrate eating and drinking time (shortest in T1) and straw eating time (longest in T1) followed a cubic trend (P = 0.02). Time spent lying down was shortest and ruminating in standing position longest in T1 and T2. Delay of feeding time resulted in greater daily maximum salivary cortisol concentration (quadratic P = 0.04), which was greatest at 0 h in T1 and at 12 h after feeding in T2 (P < 0.05). Daily mean fecal glucocorticoid metabolites were greatest in T1 and T3 (cubic P = 0.04). Ruminal pH showed a treatment effect at wk 1 because of increased values in T1 and T3 (cubic P = 0.01). Delaying feed delivery time was not detrimental for rumen function because a stress response was triggered, which led to reduced concentrate intake, eating rate, and size of first meal, and increased straw intake. Increased salivary cortisol suggests that animal welfare is compromised.

Estimation of genetic variance for macro- and micro-environmental sensitivity using double hierarchical generalized linear models

Background: Genetic variation for environmental sensitivity indicates that animals are genetically different in their response to environmental factors. Environmental factors are either identifiable (e.g. temperature) and called macro-environmental or unknown and called micro-environmental. The objectives of this study were to develop a statistical method to estimate genetic parameters for macro- and micro-environmental sensitivities simultaneously, to investigate bias and precision of resulting estimates of genetic parameters and to develop and evaluate use of Akaike’s information criterion using h-likelihood to select the best fitting model. Methods: We assumed that genetic variation in macro- and micro-environmental sensitivities is expressed as genetic variance in the slope of a linear reaction norm and environmental variance, respectively. A reaction norm model to estimate genetic variance for macro-environmental sensitivity was combined with a structural model for residual variance to estimate genetic variance for micro-environmental sensitivity using a double hierarchical generalized linear model in ASReml. Akaike’s information criterion was constructed as model selection criterion using approximated h-likelihood. Populations of sires with large half-sib offspring groups were simulated to investigate bias and precision of estimated genetic parameters. Results: Designs with 100 sires, each with at least 100 offspring, are required to have standard deviations of estimated variances lower than 50% of the true value. When the number of offspring increased, standard deviations of estimates across replicates decreased substantially, especially for genetic variances of macro- and micro-environmental sensitivities. Standard deviations of estimated genetic correlations across replicates were quite large (between 0.1 and 0.4), especially when sires had few offspring. Practically, no bias was observed for estimates of any of the parameters. Using Akaike’s information criterion the true genetic model was selected as the best statistical model in at least 90% of 100 replicates when the number of offspring per sire was 100. Application of the model to lactation milk yield in dairy cattle showed that genetic variance for micro- and macro-environmental sensitivities existed. Conclusion: The algorithm and model selection criterion presented here can contribute to better understand genetic control of macro- and micro-environmental sensitivities. Designs or datasets should have at least 100 sires each with 100 offspring.

Prevalence of Methicillin-Resistant Staphylococci on a Farm: Staff can Harbour MRS When Animals do Not

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Granjas leiteiras na região de Ribeirão Preto - SP

On the activities of dairy farm, the constructions for the animals are basic and of utmost importance in the production process, their designs should be based on technical and economic solutions, which offer extremely efficient and functional conditions. The objectives of this work was to research and study the characteristics of dairy farms located in some towns near Ribeirao Preto and the south of Minas Gerais State and recommend solutions based on the literatures for the execution of dairy projects around Ribeirao Preto region. The study was conducted based on theoretical and in loco observations, considering the following parties of dairy farm: free stall, calves housing, milking room and its annexes (footbath, foot clean and waiting corral). The results obtained of this study appeared that most of the dairy farms were designed without technical and effective economical solutions.

Parâmetros de dimensionamento para biodigestores batelada operados com dejetos de vacas leiteiras com e sem uso de inóculo

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Identification of a bisegmented double-stranded RNA virus (picobirnavirus) in calf faeces

To determine the incidence of rotavirus infection among dairy herds in the State of Sdo Paulo, Brazil, 576 faecal samples obtained from calves aged 1-45 days with and without diarrhoea, reared on 63 dairy cattle farms, were analyzed. Polyacrylamide gel electrophoresis (PAGE) identified 28 samples positive for group A rotavirus, while four samples, two diarrhoeic and two non-diarrhoeic, showed a bisegmented genome with a typical picobirnavirus pattern. Electron microscopy revealed spherical virus particles with a diameter of 37 nm and without a defined surface structure. The present study is the first report of a bisegmented virus identified in cattle in Brazil. (C) 2003 Elsevier B.V. Ltd. All rights reserved.

Biodigestão anaeróbia de dejetos de bovinos leiteiros submetidos a diferentes tempos de retenção hidráulica

Utilizando-se biodigestores contínuos, abastecidos com dejetos de bovinos leiteiros e operados sob três tempos de retenção hidráulica, avaliou-se o efeito do processo de digestão anaeróbia sobre o número de microrganismos indicadores de poluição fecal, sobre a ocorrência de ovos e larvas de helmintos parasitas de ruminantes, analisando-se também os teores de sólidos totais e voláteis do afluente e dos efluentes, bem como a produção e a qualidade do biogás produzido. Verificou-se que vinte dias de retenção hidráulica foram suficientes para reduzir significativamente o número de microorganismos indicadores de poluição fecal e a quantidade de ovos de helmintos parasitas de ruminantes. Os resultados obtidos nas análises de sólidos totais e voláteis, bem como a produção de biogás (m³/dia), permitem concluir que o biodigestor modelo Chinês operado com 20 dias de tempo de retenção hidráulica, apresentou mais eficiência. Vale ressaltar que vinte dias de retenção foram insuficientes para impedir a sobrevivência de larvas de helmintos parasitas de ruminantes.

Rotavírus bovino: fatores de risco, prevalência e caracterização antigênica de amostras em rebanhos leiteiros no estado de São Paulo

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Pesquisa de anticorpos anti-Neospora caninum em bovinos leiteiros, cães e trabalhadores rurais da região Sudoeste do Estado de Mato Grosso

Considerando a importância da neosporose interferindo na produtividade animal, avaliou-se a frequência de anticorpos anti-Neospora caninum em amostras de soros de bovinos leiteiros da Região Sudoeste do Estado de Mato Grosso, Brasil, complementando-se com amostras sorológicas colhidas de cães e de humanos que conviviam nas mesmas propriedades rurais amostradas. Um total de 1.036 amostras de soros foram analisadas, sendo 932 de fêmeas bovinas leiteiras, 37 de cães e 67 de humanos, provenientes de 24 propriedades e examinados por meio da reação de imunofluorescência indireta (RIFI). As amostras de soros humanos reagentes foram testadas novamente por Western-blotting para confirmação dos resultados. Anticorpos anti-N. caninum foram encontrados em 499 bovinos (53,5%), em pelo menos um animal positivo por propriedade, em 25 caninos (67,6%) e em sete humanos (10,5%). Não houve diferença significativa no número de bovinos positivos por faixa etária. Os resultados obtidos indicam uma ampla disseminação de N. caninum na região estudada.

Efeito da linhagem citoplasmática sobre a produção de leite em bovinos da raça Caracu

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Eficiência reprodutiva e produtiva em rebanhos leiteiros comerciais monitorados por sistema informatizado

O estudo foi conduzido com os objetivos de analisar o desempenho produtivo e algumas medidas de eficiência reprodutiva de 1877 vacas provenientes de quatro grupos genéticos Holandês ¾ Zebu e estimar os parâmetros genéticos pertinentes. Os animais pertenciam a três rebanhos comerciais que foram monitorados pelo Sistema Computacional de Informação DAISY (The Dairy Information System), durante período de 1989 a 1998. Para consistência dos dados, formação dos arquivos e análises preliminares foram usados os procedimentos disponíveis no SAS (Statistical Analysis System), enquanto os componentes de (co)variância foram estimados pelo método de máxima verossimilhança restrita livre de derivada (MTDFREML), sob um modelo animal. Os efeitos de grupo genético e ano do parto foram significativos sobre a idade da vaca ao primeiro parto (IPC), intervalo parto - primeiro serviço (PP1S), duração da lactação(DL), produção total de leite (PT) e produção de leite por dia de intervalo de parto (PLIEP). As estimativas de herdabilidade (h²) para as características reprodutivas ficaram próximas de zero, evidenciando grande dependência do manejo oferecido aos rebanhos, enquanto o valor de 0,28 para a h² da PT mostrou variância genética aditiva média. A correlação genética entre PT e DL de 0,81 pode ser considerada de alta magnitude.

Avaliação genética de touros da raça Gir para produção de leite no dia do controle e em 305 dias de lactação

Dados de 32.779 controles mensais, de 3.605 lactações em 305 dias (PL305), de 2.082 vacas Gir, filhas de 281 touros, com partos ocorridos de 1987 a 1999 em 11 rebanhos, foram usados com o objetivo de verificar a viabilidade de utilização da produção de leite no dia do controle (PLDC) em avaliações genéticas de touros da raça Gir. Foram realizadas análises univariadas das PLDC1 a PLDC10 e da PL305 pelo método de máxima verossimilhança restrita, sob modelo animal, incluindo as três primeiras lactações como medidas repetidas de um mesmo animal, diferenciados conforme o grupo contemporâneo de rebanho-ano-estação, de acordo com a idade da vaca ao parto e, do intervalo parto-primeiro controle na PLDC1. As médias observadas e os respectivos desvios-padrão (kg) para PLDC1 a PLDC10 e PL305 foram: 11,97±4,64; 11,93±4,68; 10,98±4,40; 10,18±4,12; 9,66±3,88; 9,20±3,69; 8,63±3,51; 8,08±3,33; 7,59±3,27; 7,22±3,15 e 2.746,17±1.299,90. As estimativas de herdabilidade para as PLDC1 a PLDC10 foram de 0,26; 0,19; 0,18; 0,20; 0,15; 0,13; 0,14; 0,10; 0,11 e 0,10, respectivamente; para a PL305 foi de 0,18. As correlações de ordem dos valores genéticos preditos de 281 touros, obtidos entre as PLDC e a PL305, foram altas, oscilando de 0,85 a 0,94. O percentual de coincidência de touros que seriam selecionados pelos valores genéticos preditos das PLDC2 a PLDC5 foram acima de 80%, a partir de 5% dos melhores classificados pela PL305. em algumas PLDC o nível de coincidência de classificação dos touros com a PL305 foi muito baixo.