This study aimed to assess the thermoregulatory responses of Santa Inês (SI), Dorper x Santa Inês (CH) and White Dorper x Santa Inês sheep (CW) to direct solar radiation in Southeast Brazil. Thirty adult non-pregnant and non-lactating Santa Inês (SI) hair ewes and their crosses with Dorper (hair ewes) and White Dorper (wool ewes) were allocated into three groups n = 10 and exposed to continuous solar radiation ...
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) o...
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...
This study’s main goal was to evaluate the thermoregulatory responses velocity through the variation of rectal temperature (RT), related to the thermolytic pathways, respiratory rate (RR) and sweating rate (SR) among different sheep breeds. Ninety female sheep, eighteen of each breed: Santa Ines and Morada Nova (Brazilian hair breeds), Texel, Suffolk and Ile de France (wool breeds) were challenged during three ...
Thirty Brangus bulls were used in a 90-d study to assess the effect of artificial shading on the performance and reproductive characteristics of semi-confined cattle. Animals were kept in four one-ha paddocks in two groups of eight for shade treatment (5 m²/animal of 80% solar block shade cloth) and two groups of seven animals in no-shade treatment. Each treatment had two homogeneous groups, each divided into h...
The study aimed to evaluate reactivity of horses during usual brushing management against the repeated presence of an unknown sonorous stimulus. Twenty Mangalarga Marchador horses, distributed in different categories (mares and foals), were evaluated. The animals were allocated into the control treatment (N = 10) and the treatment with unknown sonorous stimulus (N = 10) from a rattle and a tambourine. Four cons...
Physiological and productive responses were studied in five Holstein cows in thermal comfort (T1), stress by exogenous adrenocorticotropic hormone (ACTH) administration (T2) and heat stress (T3) to compare acute and punctual stress (ACTH) and prolonged stress (heat stress). During T1 and T2, cows were housed in a climatic-free stall barn. In T3, the animals were kept in a climatic room (air temperature of 37°C ...
The thermotolerance is the cell adaptation caused by a single exposure to heat,severe but not lethal. which enables the organismo to survive a subsequente lethal stress by the synthesis or accumulation of HSP.The results did not show a increase of HSP in Nelore cow leukocytes. The nelore leukocytes mantain abundance of transcripts in 38 and 40ºC but had a sunbstancial decrease at 42ºC , probably because at this...
The results show that hair breed of tropical origin is affected by sun exposure. However, sheep are able to return to the initial physiological state very quickly showing differents degrees of resistance to thermal variances
O estudo foi desenvolvido para investigar os efeitos da suplementação dietética de cromo sobre os indicadores de bem-estar de ovinos confinados. Sessenta e quatro cordeiros cruzados White Dorper x Santa Inês, desmamados aos sessenta dias de idade, foram divididos em dois grupos para terminação, por sessenta dias, em confinamento: grupo controle e grupo que recebeu suplementação de 2 mg cromo orgânico diariament...