Variation in rectal temperature of cattle in a tropical environment and its relation to growth rate

Turner, HG

doi:10.1017/s0003356100041611

Cited by 39 publications

(28 citation statements)

References 14 publications

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“…Genetic correlations between resistance to heat stress and growth and reproduction traits (Turner, 1982 and1984;Burrow, 2001;Burrow and Prayaga, 2004) are generally significantly negative (favourable), emphasising there are many genes in common between genes controlling growth and reproduction in the tropics and rectal temperatures when ambient temperatures are high. On the basis of this review, most economically important productive and adaptive traits are at least moderately heritable, indicating they will respond to selection.…”

Section: Component Traits Of Female Reproductionmentioning

confidence: 99%

Importance of adaptation and genotype × environment interactions in tropical beef breeding systems

Burrow

2012

Animal

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This paper examines the relative importance of productive and adaptive traits in beef breeding systems based on Bos taurus and tropically adapted breeds across temperate and (sub)tropical environments. In the (sub)tropics, differences that exist between breeds in temperate environments are masked by the effects of environmental stressors. Hence in tropical environments, breeds are best categorised into breed types to compare their performance across environments. Because of the presence of environmental stressors, there are more sources of genetic variation in tropical breeding programmes. It is therefore necessary to examine the genetic basis of productive and adaptive traits for breeding programmes in those environments. This paper reviews the heritabilities and genetic relationships between economically important productive and adaptive traits relevant to (sub)tropical breeding programmes. It is concluded that it is possible to simultaneously genetically improve productive and adaptive traits in tropically adapted breeds of beef cattle grazed in tropical environments without serious detrimental consequences for either adaptation or production. However, breed-specific parameters are required for genetic evaluations. The paper also reviews the magnitude of genotype 3 environment (G 3 E) interactions impacting on production and adaptation of cattle, where 'genotype' is defined as breed (within a crossbreeding system), sire within breed (in a within-breed selection programme) or associations between economically important traits and single nucleotide polymorphisms (SNPs -within a marker-assisted selection programme). It is concluded that re-ranking of breeds across environments is best managed by the use of the breed type(s) best suited to the particular production environment. Re-ranking of sires across environments is apparent in poorly adapted breed types across extreme tropical and temperate environments or where breeding animals are selected in a temperate environment for use in the (sub)tropics. However, G 3 E interactions are unlikely to be of major importance in tropically adapted beef cattle grazed in either temperate or (sub)tropical environments, although sex 3 environment interactions may provide new opportunities for differentially selecting to simultaneously improve steer performance in benign environments and female performance in harsher environments. Early evidence suggests that re-ranking of SNPs occurs across temperate and tropical environments, although their magnitude is still to be confirmed in well-designed experiments. The major limitation to genetic improvement of beef cattle over the next decade is likely to be a deficiency of large numbers of accurately recorded phenotypes for most productive and adaptive traits and, in particular, for difficult-to-measure adaptive traits such as resistance to disease and environmental stressors.

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Section: Component Traits Of Female Reproductionmentioning

confidence: 99%

Importance of adaptation and genotype × environment interactions in tropical beef breeding systems

Burrow

2012

Animal

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“…Silva (2000) suggested a series of traits associated with heat tolerance. Type and colour of the coat are important (Turner 1984;Finch et al 1984), animals with dark coats and therefore higher absorption of thermal radiation being more susceptible to thermal radiation than animals with light coats (Silva 1998). In the tropics, studies have shown slower growth rates with dark coated animals (Robertshaw 1986), but according to Cunha et al (2004), Brazilian Santa Ines sheep farmers have preferred black-coated animals and other coat colours are disappearing.…”

Section: Introductionmentioning

confidence: 99%

Skin and coat traits in sheep in Brazil and their relation with heat tolerance

McManus¹,

Louvandini

Gugel

et al. 2010

Trop Anim Health Prod

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The objective of this study was to evaluate and compare physical parameters in groups of sheep with different phenotypic characteristics in the Centre-west region of Brazil. Five groups of sheep, with nine animals per group, were selected, three groups of Santa Inês animals with different coat colours (white, brown and black), one group with crossbred animals (Santa Inês × Bergamasca) and one group with animals of the Bergamasca breed. The following traits were evaluated: coat thickness, number and length of hair, pigmentation level in the coat and the skin as well as the percentage area of sweats glands in the skin tissue, carried out by histological analysis. The number of hairs and the area of sweats glands were not significantly different between the evaluated groups. The Bergamasca breed showed low pigmentation of the skin and long hairs. The levels of pigmentation of the hair and of the skin were highly correlated. Between the Santa Inês groups, the group with white hair showed the better parameters for heat adaptation, while the brown hair group showed the lower heat adaptation when compared with another hair breed groups.

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“…The type and colour of coat found is very important for heat resistance (Turner 1984;Finch et al 1984). It is thought that animals with a dark coat, and therefore with greater absorption of thermal radiation, are more susceptible to heat stress than those with a light coloured coat (Silva 1998).…”

Section: Introductionmentioning

confidence: 99%

Heat tolerance in Brazilian sheep: Physiological and blood parameters

McManus

Paludo

Louvandini

et al. 2008

Trop Anim Health Prod

222

116

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Thirty Santa Ines adult, non-lactating, non-pregnant ewes, ten with a brown coat, ten black coated and ten white coated, as well as ten Bergamasca and ten of mixed breed were used to evaluate the effect of climate on physiological and blood parameters in sheep. Two sample collections were taken (6 AM: and 2 PM: ) on six days. Sweating rate (SR), heart (HR) and breathing rates (BR), complete hemogram, rectal (RT) and skin temperatures (ST) were measured. Variance analyses were carried out using SAS(R). In general, there were significant differences between animals due to skin type, time and day of collection. White coated animals showed lower HR, BR and RT, with afternoon parameters higher than morning. Correlations between HR, BR, RT, SR and ST were medium and positive. Correlations between physiological and blood traits were in general negative and medium. Packed Cell Volume (PCV), total plasma proteins, red blood cell count and hemoglobin concentration had high positive correlations between each other. The first two autovectors explained 49% of variation between traits. White coated Santa Ines animals were shown to be better adapted to climatic conditions in Central Brazil and wool sheep more affected by heat.

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Variation in rectal temperature of cattle in a tropical environment and its relation to growth rate

Cited by 39 publications

References 14 publications

Importance of adaptation and genotype × environment interactions in tropical beef breeding systems

Importance of adaptation and genotype × environment interactions in tropical beef breeding systems

Skin and coat traits in sheep in Brazil and their relation with heat tolerance

Heat tolerance in Brazilian sheep: Physiological and blood parameters

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