Effect of heat stress on six beef breeds in the Zastron district: The significance of breed, coat colour and coat type

Abstract

A study was done to determine which factors had the greatest influence on a heifer's susceptibility to heat stress. Parameters tested were breed, coat colour, coat score, hide thickness, weight gain, respiration rate and body condition score. The study was conducted in the southeastern Free State. Afrikaner, Bonsmara, Braford, Charolais, Drakensberger and Simmentaler heifers were subjected to a heat tolerance trial. A total of 60 heifers, 10 of each breed were evaluated. Rectal temperature (T re ) was used as a parameter to determine heat stress. The heifers were evaluated on 10 days, at 14:00 during the winter of 2007 and on seventeen days, at 14:00 during the summer of 2007/8 (after 1 h in the sun, no access to shade). In winter a significant difference in rectal temperature T re between breeds was measured on seven occasions. Phenotypical factors tested for did not affect T re in winter. In summer significant differences in T re were measured on 12 occasions between breeds. The following factors had a significant influence on T re in the following breeds: Afrikanerhide thickness, Bonsmara -hide thickness, Charolais -coat score.

Multivariate Analysis of Thermal Adaptive Profile of Three Genetic Groups of Duck

“…Heat tolerance is an important heritable economic trait that is central to livestock performance and profitable investment by livestock farmers most especially in hot environments. Therefore, the ability to maintain homeostasis under heat stress is a valuable trait in Sub-tropical and Tropical regions which helps to maximize utilization of animal genetic resources (Foster et al, 2009). Though empirical reports on heat tolerance of duck genotypes are not existing or sparse; nevertheless, the trend of result in the present study whereby local Muscovy and crossbred Mule ducks had superior thermal tolerance than the exotic Common duck align with the report of related studies on turkey (Ilori et al, 2011;Yakubu et al, 2012) and chicken (Aengwanich, 2008) genotypes.…”

“…The ability to maintain homeostasis under heat stress is a valuable trait in sub-tropical and tropical regions which helps to maximize utilization of animal genetic resources (Foster et al, 2009). Therefore, study involving application of multivariate analyses to data generated from different heat stress indicators (heat stress proteins, biochemical, physiological, molecular, endocrinological, haematological e.t.c.)…”

Genetic variation in physiological adaptation of local, exotic and crossbred ducks to heat stress in a tropical environment

“…Heat-tolerance is a valuable quantitative economic trait and can be passed from generation to generation. The ability to maintain homeostasis under heat stress is a valuable trait in sub-tropical and tropical regions and this helps to maximize utilization of animal genetic resources (Foster et al, 2009). Between genotypesex analyses, revealing lower values for both sexes of Muscovy and Mule ducks in contrast to Mallards is a pointer to their superior thermal adaptation and accentuate further that they were genetically superior in thermal tolerance than Mallards.…”

Characterization of a composite population of beef cattle in subtropical south Texas and the effect of genes for coat type and color on preweaning growth and influence of summer breeding on sex ratio

“…However, there is a paucity of published reports concerning potentially favorable effects of lighter colors on breeding cattle under pasture or range conditions. In published breed evaluation studies it is acknowledged that coat color is difficult to isolate as a factor and is confounded with the breed effect (Foster et al, 2009).…”