Climatic Effects on Productive Traits in Livestock
By A. Nardone, B. Ronchi, Nicola Lacetera, U. Bernabucci. Veterinary research communications, 2006
169 citations recorded by the source corpus.
Each species, breed or animal category, correlated with its physiological state, has a comfort zone, in which the energy expenditure of the animal is minimal, constant and independent of environmental temperature. Outside of this zone, the animal experiences stress to maintain homeothermy. This requires extra energy to thermoregulate, so that less energy is available for production processes (Bianca, 1976). The animal modifies its behaviour, especially feeding, physiological and metabolic functions and the quantity and quality of its production. When an animal is for a medium/long period outside of its zone of thermoneutrality it activates mechanisms of acclimatization, whereas population of animals experiencing significant climatic changes can adopt, by genetic adaptation, modifying genetic and phenotypic features over generations. The more the impact of the climatic conditions on the animal varies in magnitude and length, the more difficulties the organism has to maintain homeothermy. Outside the extreme limits of this zone, the organism experiences hypothermy or hyperthermy until it dies from cold or heat. The difference between normal and lethal body temperature is in the order of 15–25◦C in the cold and of only around 3–6◦C in the heat. This explains why cold represents less of a problem than heat (Bianca, 1976; Collier et al., 1982) and why high selected productive animals, with high endogenous heat production, show high tolerance to cold and low tolerance to heat. Consistently, the limits of the thermal comfort zone for these selected animals becoming lower and the animals are becoming more and more sensitive to heat stress (HS). Animals have two means by which to exchange heat with the environment: via evaporative or latent (sweating and painting) or non-evaporative or sensible (conduction, convection, radiation) systems (Yousef, 1987). Because air temperature alone is an imperfect measure of the thermal environment, many attempts have been made to combine the effects of two or more thermal environmental factors to better represent the influence of sensible and latent heat exchange between an organism and its environment. The Temperature Humidity Index (THI) (Johnson, 1980) is the most extensively employed index for moderate to hot conditions, even though some limitations exist related to air speed and radiation heat loads (Hahn et al., 2003). Heat and draught
Subfields: Animal Science and Zoology, Ecology, Genetics
View Paper: https://www.semanticscholar.org/paper/7a804bbce01133bf1077fe49116a953b9cc09c93
How researchers see this paper
The researchers whose trusted networks rank it highest, strongest advocate first. Every researcher gets a different order.
In Animal Science and Zoology
In Genetics
Citations in the corpus
- Metabolic and hormonal acclimation to heat stress in domesticated ruminants. (2010, background): “Moreover, a cow weighing 700 kg and yielding 60 kg milk/day produces about 44 171 kcal of heat/day; the same cow produces 25 782 kcal of heat/day at the end of lactation (milk yield of 20 kg/day) (Nardone et al., 2006).”