Morphological Changes in Swine Associated with Environmental Temperature

Abstract

Ten animals from two litters of English large white pigs were weaned at 12—15 days of age and placed one per cage within constant—temperature rooms. In the first group, a comparison was made between three animals raised at 5°C and their littermates raised at 35°C. There were marked differences in appearance and in gross morphology. Those from the cold environment had more hair, were shorter and more stocky, and had a shorter tail and smaller ears than their littermates. A second group of animals were raised at 20°C and 35°C; it was found that with respect to all measurements the 20°C pigs were intermediate between the 5° and 35°C animals. These observations accord with Bergmann's Rule that animals raised in colder environments are characterized by a reduced surface area/body weight ratio. The results likewise substantiate Allen's Rule that in colder climates the length of appendages and of extremities is reduced.

Locomotion and body proportions of the Saint-Césaire 1 Châtelperronian Neandertal

“…There is developmental plasticity in mammalian body proportions as a result of thermal stress (30,34). Yet, among at least recent human immigrant groups displaced to different environments, there is little change in body proportions, even over a number of millennia (23).…”

Allen's Rule Revisited: Temperature Influences Bone Elongation During a Critical Period of Postnatal Development

“…Sumner (1909) was the first of many biologists to report an "Allen-type effect" after rearing laboratory mice at cold and warm temperatures throughout their active growth period (Sumner, 1909). Others have confirmed this basic observation in various species, including rats (Chevillard et al, 1963;Lee et al, 1969;Riesenfeld, 1973;Steegmann, 2007), mice (Sundstroem, 1922;Ogle, 1934;Ashoub, 1958;Harland, 1960;Barnett and Scott, 1963;Harrison, 1963;Noel and Wright, 1970), rabbits (Ogle and Mills, 1933), and pigs (Weaver and Ingram, 1969). The consistent result among these studies is that animals reared in cold conditions have shorter ears, limbs, and tails, while those raised at warmer temperatures have extremities that are lengthened in a gradient fashion with increasing temperature.…”

Effects of Cold Exposure on Young Growing Lambs

“…These studies, however, have not examined the possible effects of cold temperature exposure on morphological adaptations which may serve to reduce the degree of environmental stress experienced. Pronounced morphological adaptations to cold are considered to be genetically controlled but studies by Weaver and Ingram (1969) and Heath and Ingram (1979) have shown that a relatively short-term exposure of growing pigs to a cold environment can result in marked alterations in development.…”