Multivariate analysis of characteristics that influence heat tolerance in horses, sheep and cattle

Made available in DSpace on 2014-07-29T15:13:39Z (GMT). No. of bitstreams: 1 MARLOS_TESE_FINAL.pdf: 1188390 bytes, checksum: 139a8023d47162b34756138701932d3f (MD5) Previous issue date: 2009-03-27Heat stress is a limiting factor in animal production in the tropics. The physical, physiological and hematological are often used to evaluate the adaptation of animals to heat. The objective was to perform multivariate analysis of physiological characteristic "tolerance to heat, horses, sheep and cattle in the Federal District, to determine whether measured characteristics were able to separate groups of animals and determine the most important variables in differentiating groups in the adaptation of animal heat. A total of 40 horses, 50 sheep and 90 cattle, all adults. The quantitative characters were subjected to multivariate statistical tests of cluster analysis and canonical discriminant. Analyses were performed in the Statistical Analysis System - SAS ® procedures using cluster stepdisc, cancorr and discrim. The dendrogram was able to separate and demonstrate the genetic distance between groups of animals analyzed. The canonical analysis separated the individuals into groups. The discriminant analysis identified the variables that are most important in adapting these to the heat in the Federal District, the conditions were in the polls.O estresse térmico é considerado um fator limitante na produção de animais nos trópicos. As características físicas, hematológicas e fisiológicas são frequentemente utilizadas para avaliar a adaptação dos animais ao calor. Objetivou-se realizar análise multivariada das característcias fisiológicas de tolerância ao calor, em equinos, ovinos e bovinos do Distrito Federal, para determinar se as características medidas foram capazes de separar os grupos de animais e determinar as variáveis mais importantes na diferenciação dos grupos na adaptação do animal ao calor. Foram utilizados 40 cavalos, 50 ovelhas e 90 bovinos, todos adultos. Os caracteres quantitativos foram submetidos aos testes estatísticos multivariados de análise de agrupamento, discriminante e canônica. As análises foram realizadas no programa estatístico Statistical Analysis System - SAS ® usando os procedimentos cluster, stepdisc, cancorr, e discrim. O dendrograma foi capaz de separar e demonstrar a distância entre os grupos genéticos dos animais analisados. A análise canônica separou os indivíduos em grupos. A análise discriminante identificou as variáveis que têm maior importância na adaptação destes animais ao calor no Distrito Federal, nas condições em foram realizadas as pesquisas

Infrared Thermography to Evaluate Heat Tolerance in Different Genetic Groups of Lambs

Heat stress is considered a limiting factor for sheep production. We used information from physiological characteristics linked to heat tolerance to determine whether infrared thermography temperatures were able to separate groups of animals and determine the most important variables in this differentiation. Forty-eight four-month-old male lambs from eight genetic groups were used. Physiological (rectal temperature–RT, heart rate–HR, respiratory rate–RR) and blood traits, infrared thermography temperatures, heat tolerance indices, body measurements, weight and carcass traits were measured. Statistical analyses included variance, correlations, factor, discrimination and regression. Observing the correlations between physiological characteristics (RT, RR and HR) with temperatures measured by infrared thermography, regions for further studies should include the mean temperature of flank, nose and rump. Results show that there are strong relationships between thermograph measurements and RR, RT and HR in lambs, which are suggested to be directly correlated with heat tolerance capacity of the different genetic groups evaluated in this study. The assessment of body surface temperature measured by the thermograph could be used as a noninvasive tool to assess heat tolerance of the animals

Maternal offspring behaviour in curraleiro pé duro naturalized cattle in brazil

The objective of the present study consisted of describing dam and calf suckling behaviour of Curraleiro Pé Duro cattle. In this study, 38 mother-offspring pairs and one mother-offspring-orphan trio were observed for 10 hours daily during three consecutive days spaced every four months over a period of one year. After identification,theanimalswereobserved under field conditions where calf posture and the number of sucklingepisodes(NS),meansucklingduration(MSD),total suckling duration per day (TSD) as well as natural weaning of these animals were recorded. The model assessed the effects of calf sex and age as well as feeding time. Suckling episodes (70.6%) had a duration of one to five minutes and the calf that suckled in the inverted parallel position had greater chances of success during suckling (99.5%); the younger animals had a shorter mean suckling duration (4.0±0.6 minutes) than the older ones (7.5±1.2 minutes) but they showed a higher number of suckling episodes (6.29±1.00 vs. 1.33±0.04 feeds in 10 hours for young and older calves). Only the factor age in the firstthree months was significant for NS,MSD,and TSD;males and females had similar suckling episode length and distribution. While these animals show some traits similar to other cattle breeds such as feeding their calves early in the morning and late in the afternoon, the dams spend large periods of the day away from their calves and suckling is more frequent but for shorter periods of time compared with other breeds. Other unique features such as allo-suckling and formation of day-long crèches are observed in this breed. © 2013 Sociedade Brasileira de Zootecnia;