Feto-maternal relationships in goats during heat and cold exposure

Maternal and fetal body temperatures sere measured in five Beer goats, of m ean mass 64 +/- 8 kg, using temperature-sensitive radiotelemeters implanted intra-abdominally. Body temperatures were recorded every 5 min. Throughout the last month of gestation, fetal temperature mas approximately 0.6 degre esC higher than that of the mother, in normal laboratory conditions (ambien t air temperature: 21-24 degreesC). This fete-maternal temperature differen ce between the goat fetus and its mother is similar to that found in other mammals, including sheep. When the pregnant goats were subjected to shortte rm heating and cooling, the difference between maternal and fetal body temp eratures changed. Thus the mean difference between fetal and maternal body temperatures decreased from 0.4 to 0.2 degreesC during 2 h of beating, whil e it widened from 0.3 to 0.7 degreesC during 6 h of cooling. These data sup port the idea that the fetus is thermally protected from excursions of body temperature during changes in the mother's thermal environment. Reports of goat stock losses and abortions during cold spells in their natural habita ts may be the result of more severe and/or prolonged cold exposures that no t only adversely affect fetal or maternal body temperature, but also influe nce other aspects of metabolism.