Dog Development
Introduction
The domestic dog (Canis lupus familiaris) has been derived from an ancestoral wolf and now consists of a breed family of more than 300 worldwide, with extensive variations in morphology (size, shape and weight). The average canine gestation period from ovulation to birth (parturition) approximately 64 days. There have been identified about 400 congenital disorders relating to dog development.
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Some Recent Findings
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Taxon
NCBI Taxonomy Browser Canis lupus familiaris (Genbank common name: dog)
Synonyms: Canis familiaris, Canis domesticus, Canis canis
Chromosomes: 40 (38, X, Y)
Genetic code: Translation table 1 (Standard)
Mitochondrial genetic code: Translation table 2 (Vertebrate Mitochondrial)
Lineage( full ):cellular organisms; Eukaryota; Fungi/Metazoa group; Metazoa; Eumetazoa; Bilateria; Coelomata; Deuterostomia; Chordata; Craniata; Vertebrata; Gnathostomata; Teleostomi; Euteleostomi; Sarcopterygii; Tetrapoda; Amniota; Mammalia; Theria; Eutheria; Laurasiatheria; Carnivora; Caniformia; Canidae; Canis; Canis lupus
Development Overview
Days shown below relate to days after ovulation (day 0).
- 48-72 h - oocytes need to complete post-ovulatory maturation to the metaphase II stage in the isthmus of the oviduct[4]
- 2 to 5 days - fertilization
- 14 to 16 days - embryo attaches to uterus
- 22 to 23 days - heartbeat visible
- 62 to 64 days - parturition (birth or whelping)
Sexual differentiation begins early in the embryonic period prenatally and continues into early postnatal life.
Caudal vena cava development- five theories to origin (right-sided supracardinal, caudal cardinal, sacrocardinal, lateral sympathetic or subcardinal veins).
Estrous Cycle
Estrus, also called "in heat" is the time of sexually receptivity and occurs every 17 to 21 days.
- Ovulation occurs 5 to 6 days prior to the first day of diestrus and is indicated by plasma progesterone concentrations higher than 2 ng/mL. (Parturition (birth or whelping) occurs between 62 to 64 days after ovulation).
- Ovulated oocytes diameter[6]
- with the zona pellucida (167.5+/-12.7 microns)
- without zona pellucida (133.9+/-5.3 microns)
- Links: Estrous Cycle
Placenta
Classified as endotheliochorial placentation forming a zonary placenta, which is a complete girdle in dogs. Three zones: girdle zone (endotheliochorial labyrinth), hemochorial hemophagous zone (marginal hematoma) and polar zone (epitheliochorial free)
Trophoblast cell invasion continues after chorioallantois villous penetration and the materno–fetal interface is described as lamellar, with fetal projections interdigitating with maternal septa.
(Data from: Miglino MA, etal., 2006 and other sources)
Male Gonad
A recent study using timed pregnancies and male embryo development identified testis differentiation at 36 days gestation. At this time Mullerian duct regression also commenced and was completed by 46 days gestation. Immunohistochemistry also identified Mullerian Inhibitory Substance (MIS) was present during this period in testes and was absent in the undifferentiated testis.[7]
Abnormalities
- Cardiac Defects
- Canine-dilated cardiomyopathy - not associated with canine desmin.[8]
- Hip dysplasia
- Congenital renal disease
Other
- Canine Eclampsia - (puerperal tetany, hypocalcemia) develops mainly in small-breed dogs with large litters.
- Brucellosis - male and female can be carriers of this sexually transmitted disease.
References
Reviews
Articles
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Books
- Complete Book of Dog Breeding by DVM Dan Rice
- Practical Dog Breeding: Principles and Practice by William Haynes (1915)
Search Pubmed
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Cite this page: Hill, M.A. (2024, June 15) Embryology Dog Development. Retrieved from https://embryology.med.unsw.edu.au/embryology/index.php/Dog_Development
- © Dr Mark Hill 2024, UNSW Embryology ISBN: 978 0 7334 2609 4 - UNSW CRICOS Provider Code No. 00098G