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Conceptus-Maternal Interactions: Introduction1
SYMPOSIUM: CONCEPTUS-MATERNAL INTERACTIONS Conceptus-Maternal Interactions: Introduction I C. J. WILCOX Dairy Science Department University of Florida Gainesville 32611
The relationship between the conceptus and its dam during pregnancy and carryover effects of this relationship postpartum have received increasing interest in the last 5 yr. The degree o f this interest is reflected in the following reports on conceptus-maternal interactions which resulted from joint efforts o f three ADSA Production Division Committees: Milk Synthesis, Physiology, and Dairy Cattle Improvement. These reports represent the state of knowledge of the subject; much o f the material has n o t been published and is now in press. Unfortunately, much of the interesting historical development of this area of science must be omitted here. Hippocrates, for example, is credited with suggesting in 460 BC that the fetus played a role in controlling its own delivery (2). Such concepts began to take form in the late 19th and early 20th centuries (1, 6). Gaines (5) suggested in 1915 that since mammary gland development was influenced by the fetus prior to parturition, milk yield of the dam possibly was influenced by the fetus. He stated further that the sire of the fetus might influence postpartum yield. Selye (8) proposed in 1934 that the placenta was an endocrine organ with mammogenic properties. Presently, we define the conceptus as the fetus plus its extra fetal membranes (chorioallantois, amino-chorion, and c o t y l e d o n s ) a n d fluids (allantoic and amnionic). As the con ° ceptus is genetically distinct from (though related to) the dam and capable o f many interactions with the maternal unit via the endocrine system, fetal genotype may influence the conceptus-maternal relationship. Animal geneticists long have been able to demonstrate that the fetus is determining the timing of its own birth to some degree. Fetal sex was noted in 1924 to influence gestation
length, i.e., males were carried longer than females (4). Effects of sire o f fetus on gestation length were noted in 1932 (7) and may have been known or suspected as early as 1850. Many subsequent studies have confirmed that gestation length, as a trait o f the fetus, exhibits appreciable paternal half-sib correlation, i.e., nonmaternal additive genetic variance is considerable as is that particular estimate of heritability. Birth weight is associated with gestation length, the former also being heritable. When either response is adjusted statistically for the other, heritabilities still are relatively high. Physiological aspects o f mammogenesis and onset of lactation were reviewed in detail recently by Erb (3), who presented 120 references which in turn cited several thousands. The following reports address the relationship between these processes and fetal development and genetic aspects o f the conceptus-maternal interaction. Until recently there have not been extensive cooperative efforts between physiologists, geneticists, nutritionists, and biochemists in this area of research. Touchberry (9) particularly has urged such in animal research and that any such efforts would be unusually productive. Hopefully the following publications, covering four major areas of conceptus-maternal interactions, will provide useful information and form a convenient base for future cooperative research.
Received January 28, 1980. 1Florida Agricultural Experiment Station Journal Series No. 1924. 1980 J Dairy Sei 63:1481-1482
1481
REFERENCES
1 Becker, R. B., and P. C. McGilliard. 1930. Measuring the influence of hormone and mechanical stimulation by means of a non-fecund lactation. J. Dairy Sei. 13:372. 2 Bedford, C. A., J.R.G. Challis, F. A. Harrison, and R. B. Heap. 1972. The role of oestrogens and progesterone in the onset of parturition in various species. J. Reprod. Fert. (Suppl.) 16:1. 3 Erb, R. E. 1977. Hormonal control of mammogenesis and onset of lactation in cows-a review. J. Dairy Sci. 60:155. 4 Fitch, J. B., P. C. MeGilliard, and G. M. Drumm. 1924. A study of the birth weight and gestation of dairy animals. J. Dairy Sci. 7:222.
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WILCOX
5 Gaines, W. L. 1915. A contribution to the physiology of lactation. Am. J. Physiol. 38:285. 6 Hill, R. L. 1919. An exceptional case o f milk secretion and its bearing on theories concerning m a m m a r y development. J. Dairy Sci. 2:19. 7 Knott, J. C. 1932. A s t u d y o f the gestation period o f Holstein-Friesian cows. J. Dairy Sci. 15:87. 8 Selye, H., J. B. Collip, and D. L. T h o m p s o n . 1934.
Journal of Dairy Science Vol. 63, No. 9, 1980
Nervous and h o r m o n a l factors in lactation. Endocrinology 18:237. 9 Touchberry, R. W. 1974. Environmental and genetic factors in development and maintenance of lactation. Ch. 19. Page 349 in Lactation. A comprehensive treatise. Vol. III. Nutrition and biochemistry o f milk/maintenance. B. L. Larson and V. R. Smith, ed. Academic Press, New York, NY.
The relationship between the conceptus and its dam during pregnancy and carryover effects of this relationship postpartum have received increasing interest in the last 5 yr. The degree o f this interest is reflected in the following reports on conceptus-maternal interactions which resulted from joint efforts o f three ADSA Production Division Committees: Milk Synthesis, Physiology, and Dairy Cattle Improvement. These reports represent the state of knowledge of the subject; much o f the material has n o t been published and is now in press. Unfortunately, much of the interesting historical development of this area of science must be omitted here. Hippocrates, for example, is credited with suggesting in 460 BC that the fetus played a role in controlling its own delivery (2). Such concepts began to take form in the late 19th and early 20th centuries (1, 6). Gaines (5) suggested in 1915 that since mammary gland development was influenced by the fetus prior to parturition, milk yield of the dam possibly was influenced by the fetus. He stated further that the sire of the fetus might influence postpartum yield. Selye (8) proposed in 1934 that the placenta was an endocrine organ with mammogenic properties. Presently, we define the conceptus as the fetus plus its extra fetal membranes (chorioallantois, amino-chorion, and c o t y l e d o n s ) a n d fluids (allantoic and amnionic). As the con ° ceptus is genetically distinct from (though related to) the dam and capable o f many interactions with the maternal unit via the endocrine system, fetal genotype may influence the conceptus-maternal relationship. Animal geneticists long have been able to demonstrate that the fetus is determining the timing of its own birth to some degree. Fetal sex was noted in 1924 to influence gestation
length, i.e., males were carried longer than females (4). Effects of sire o f fetus on gestation length were noted in 1932 (7) and may have been known or suspected as early as 1850. Many subsequent studies have confirmed that gestation length, as a trait o f the fetus, exhibits appreciable paternal half-sib correlation, i.e., nonmaternal additive genetic variance is considerable as is that particular estimate of heritability. Birth weight is associated with gestation length, the former also being heritable. When either response is adjusted statistically for the other, heritabilities still are relatively high. Physiological aspects o f mammogenesis and onset of lactation were reviewed in detail recently by Erb (3), who presented 120 references which in turn cited several thousands. The following reports address the relationship between these processes and fetal development and genetic aspects o f the conceptus-maternal interaction. Until recently there have not been extensive cooperative efforts between physiologists, geneticists, nutritionists, and biochemists in this area of research. Touchberry (9) particularly has urged such in animal research and that any such efforts would be unusually productive. Hopefully the following publications, covering four major areas of conceptus-maternal interactions, will provide useful information and form a convenient base for future cooperative research.
Received January 28, 1980. 1Florida Agricultural Experiment Station Journal Series No. 1924. 1980 J Dairy Sei 63:1481-1482
1481
REFERENCES
1 Becker, R. B., and P. C. McGilliard. 1930. Measuring the influence of hormone and mechanical stimulation by means of a non-fecund lactation. J. Dairy Sei. 13:372. 2 Bedford, C. A., J.R.G. Challis, F. A. Harrison, and R. B. Heap. 1972. The role of oestrogens and progesterone in the onset of parturition in various species. J. Reprod. Fert. (Suppl.) 16:1. 3 Erb, R. E. 1977. Hormonal control of mammogenesis and onset of lactation in cows-a review. J. Dairy Sci. 60:155. 4 Fitch, J. B., P. C. MeGilliard, and G. M. Drumm. 1924. A study of the birth weight and gestation of dairy animals. J. Dairy Sci. 7:222.
1482
WILCOX
5 Gaines, W. L. 1915. A contribution to the physiology of lactation. Am. J. Physiol. 38:285. 6 Hill, R. L. 1919. An exceptional case o f milk secretion and its bearing on theories concerning m a m m a r y development. J. Dairy Sci. 2:19. 7 Knott, J. C. 1932. A s t u d y o f the gestation period o f Holstein-Friesian cows. J. Dairy Sci. 15:87. 8 Selye, H., J. B. Collip, and D. L. T h o m p s o n . 1934.
Journal of Dairy Science Vol. 63, No. 9, 1980
Nervous and h o r m o n a l factors in lactation. Endocrinology 18:237. 9 Touchberry, R. W. 1974. Environmental and genetic factors in development and maintenance of lactation. Ch. 19. Page 349 in Lactation. A comprehensive treatise. Vol. III. Nutrition and biochemistry o f milk/maintenance. B. L. Larson and V. R. Smith, ed. Academic Press, New York, NY.