Heat tolerance in three genetic groups of lambs in central Brazil

Correa, Marilma Pachêco Chediak; Cardoso, Maximiliano Tadeu Memória; Castanheira, Marlos; Landim, Aline Vieira; Dallago, Bruno Stéfano Lima; Louvandini, Hélder; McManus, Concepta

doi:10.1016/j.smallrumres.2011.11.001

Cited by 34 publications

(36 citation statements)

References 28 publications

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“…A negative correlation between air temperature, PCV, number of RBCs and HB concentration was reported [20], while in the present study a negative relationship was also noted between these hematological constituents and THI, which can be attributed to the hemodilution effect [28]. With regard to heat tolerance indices, the inverse relationship between Iberia index and number of RBCs and HB concentration indicates that these blood constituents can be lower in the more adapted animal.…”

Section: Discussionsupporting

confidence: 58%

Heat tolerance in Brazilian hair sheep

Seixas

Melo

Tanure

et al. 2016

Asian-Australas J Anim Sci

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ObjectiveThe aim of this study was to evaluate heat tolerance using heat tolerance indices, physiological, physical, thermographic, and hematological parameters in Santa Ines and Morada Nova sheep breeds in the Federal District, Brazil.MethodsTwenty-six adult hair sheep, one and a half years old, from two genetic groups (Santa Ines: 12 males and 4 females; Morada Nova: 7 males and 3 females) were used and data (rectal temperature, respiratory rate, heart rate, skin temperatures; hematological parameters) were collected during three consecutive days, twice a day (morning and afternoon), with a total of six repetitions. Also physical parameters (biometric measurements, skin and hair traits) and heat tolerance indices (temperature-humidity index, Iberia and Benezra) were evaluated. The analyses included analyses of variance, correlation, and principal components with a significance level of 5%.ResultsThe environmental indices, in general, indicate a situation of thermal discomfort for the animals during the afternoon. Breed significantly influenced (p<0.001) physiological and physical characteristics of skin, hair, biometric measurements and Iberia and Benezra heat tolerance indices. Santa Ines animals were bigger and had longer, greater number and darker hair, thicker skin, greater respiratory rate and Benezra index and lower Iberia index compared with Morada Nova breed.ConclusionAlthough both breeds can be considered adapted to the environmental conditions of the region, Morada Nova breed is most suitable for farming in the Midwest region. The positive correlation found between the thermographic temperatures and physiological parameters indicates that this technique can be used to evaluate thermal comfort. Also, it has the advantage that animals do not have to be handled, which favors animal welfare.

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Section: Discussionsupporting

confidence: 58%

Heat tolerance in Brazilian hair sheep

Seixas

Melo

Tanure

et al. 2016

Asian-Australas J Anim Sci

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“…Despite the small difference of 0.3°C, the highest average RT observed in the rainy season can be attributed to the lower average respiratory rate (RR) and respiratory evaporation (RE) that were also observed in this period, thus resulting in less heat dissipation by respiration, which is considered to be the main heat loss mechanism of panting species (Hales and Webster 1967). This agrees with Santos et al (2006) and Correa et al (2012) that report an impaired by difficult in heat dissipation due to associate climatic factors during rainy season like high temperature and humidity. The mean RR was higher in June, September, and October (96, 92, and 91 breaths per minute, respectively); this increase can be associated with the higher RHL and T A values recorded during these months.…”

Section: Resultssupporting

confidence: 76%

Locally adapted Brazilian ewes with different coat colors maintain homeothermy during the year in an equatorial semiarid environment

Leite

Silva

et al. 2018

Int J Biometeorol

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The present paper aimed to show the thermoregulatory responses of locally adapted Morada Nova sheep with different coat colors that were exposed to direct solar radiation in an equatorial semiarid region. Animals were classified into four groups according to the coat color as follows: (1) dark red, (2) intermediate red, (3) light red, and (4) white coats. Forty Morada Nova ewes were observed in for 7 consecutive months. The experimental variables measured were rectal temperature (RT), skin surface temperature (ST), respiratory rate (RR), skin surface evaporation (CE), respiratory evaporation (RE), and heat exchange by convection (HC) and radiation (R). Data were collected from 1100 to 1400 h after the animals were exposed to 30 min direct sunlight. The results showed that all groups maintained homeothermy. The R was higher in the animals of groups 1 to 3, which also showed higher values for ST when compared to the white-coated animals. Sensible heat exchange mechanisms were not important for heat loss, and R was a significant source of heat gain from the environment for the animals. Groups 1, 2, and 3 used RR more intensely than group 4 (P value = 0.001); however, CE was higher for the white-coated animals. It was concluded that Morada Nova sheep are well adapted to the semiarid environment, regardless of coat color.

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“…30 With regard to sex, for the SW and ADG variables, males exhibited significantly better results than females, which is in agreement with the results of a study in Texel crossbred lambs. 31 T × S showed a better performance during the fattening period corresponding to a better feed conversion index and a higher economical return than the S × S genotype.…”

Section: Productive Traitsmentioning

confidence: 93%

Effect of Texel crossbreeding on productive traits, carcass and meat quality of Segureña lambs

et al. 2019

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BACKGROUND The present study aimed to assess the effect of crossbreeding a local breed (Segureña, S × S) with Texel as the sire line (Texel × Segureña crossbred, T × S) on productive traits and meat quality attributes. Sixty‐eight lambs (both males and females) from each genotype, weaned at about 45 days old and intensively fed with concentrates and cereal straw ad libitum until they were 72 days old, were used to assess productive traits, and ten animals from each genotype were used to assess meat quality. RESULTS The crossbreeding with Texel improves productivity, with a greater weight at birth (+1 kg) and at slaughter (+3 kg) and a greater average daily gain (+29 g). T × S lambs had a better conformation, less carcass fatness, and higher content of muscle (+45 g kg−1) as opposed to a lower fat content (−50.6 g kg−1). With regard to meat quality, crossbreeding with Texel provided a meat with a higher protein content (+4 g kg−1) and a lower oleic acid content (21% less), although the differences were very scarce from a sensory point of view, and non‐existent with respect to instrumental quality. CONCLUSION Crossbreeding could comprise a useful tool in the production of ovine meat in local breeds, such as Segureña, within the Mediterranean Area, and, consequently, a way of increasing the profitability of the farms. © 2018 Society of Chemical Industry

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Heat tolerance in three genetic groups of lambs in central Brazil

Cited by 34 publications

References 28 publications

Heat tolerance in Brazilian hair sheep

Heat tolerance in Brazilian hair sheep

Locally adapted Brazilian ewes with different coat colors maintain homeothermy during the year in an equatorial semiarid environment

Effect of Texel crossbreeding on productive traits, carcass and meat quality of Segureña lambs

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