The female’s cycle is mono-estrian, seasonal and lasts about 6 months. The dog’s heat therefore occurs once or twice a year. There are 4 periods in the dog’s cycle.
Proestrus : period when the female attracts males but does not accept mating. On average, it lasts 9 days but can go from 2 to 17 days. The most frequent signs of proestrus are an edema of the vulva and a sero-blood flow.
Estrus : the female accepts the male during this period. It normally lasts 9 days but can range from 3 to 21 days.
Diestrus : the female is no longer receptive to the male and rejects coitus. Physiologically, it corresponds to the establishment of the corpus luteum (metestrus) and then to its full functioning (di-estrus, production of progesterone). During this long phase of about 2 months, the female undergoes progesterone peaks. This can lead, even in the absence of fertilization, to the expression during this period of hormone-dependent signs normally associated with gestation (maternal behavior, lactation).
Anestrus : phase of sexual inactivity and ovarian rest (absence of folliculogenesis and corpus luteum). It lasts between 30 and 230 days depending on the breed. Puberty is reached when the puppy reaches about 2/3 of its adult weight. It therefore occurs at the age of 6 to 20 months depending on the size of the animal as defined by breed criteria.
Gestation lasts an average of 62 days and parturition is generally unassisted except for brachycephalic dogs (short, broad head). The size of the litters is very variable: from 1 to sometimes more than 12 puppies.
To date, no hormonal treatment allows reliable control of the female sexual cycle, prohibiting any experimental programming of births.
Genomic databases :
Phenotypic database :
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Breen M. et al. (2004). “An Integrated 4249 marker FISH/RH Map of the canine genome.”
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Hitte C. et al. (2005). “Facilitating genome navigation: survey sequencing and dense radiation-hybrid gene mapping.”
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Lindblad-Toh K. et al. (2005). “Genome sequence, comparative analysis and haplotype structure of the domestic dog.”
Nature 438, 803-819
Sargan D. (2007). “An Extended Microsatellite Set for Linkage Mapping in the Domestic Dog.”
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[FR] Vanbelle P. (2008). “Intérêt du modèle canin en thérapie génique.”
Thèse de doctorat vétérinaire. Ecole Nationale Vétérinaire d’Alfort. p 194
Pang J.F. et al. (2009). “mtDNA Data Indicates a Single Origin for Dogs South of Yangtze River, less than 16,300 Years Ago, from Numerous Wolves.”
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