Resources

Welcome to the EGZAC resources page on which you can find information on the gestation lengths of species in our database, ovulation in mammals, useful references, and important product protocols. Please contact contraception@chesterzoo.org if there is any information not on this page that you would like to have. 

User manual

  • Full (33 pages)

You can find a copy of our user manual here

  • Short version (6 pages)

English version

German version

 

Product protocols

You can find useful product protocols on our documents page

 

Useful references

You can find a useful list of references on wildlife contraception, contraception and population management, and species specific information on reproductive physiology and contraception here

 

Gestation length

Interested in knowing the gestation length of animals in your care? You can find a list of gestation lengths for species in our database here.

 

Ovulation in mammals

Ovulation is the process in which a mature egg is released from the ovaries in order to be fertilised by sperm. In most mammals, females will be one of two types of ovulators: spontaneous or induced. Spontaneous ovulation occurs independently of a copulatory stimulus and is controlled by cyclical fluctuations of various hormones. 

 In females where ovulation is induced, a female will ovulate due to an externally derived stimulus which may come during, or just before mating. This stimulus may be due to physical intromission, sperm, or certain pheromones. In species that experience copulatory-induced ovulation it is ill advised to use any contraception that allows the female to ovulate without a resulting pregnancy due to the risk of pseudopregnancy. Exposure to prolonged periods of circulating progestogens associated with pseudopegnancy increase the risk of developing endometrial hyperplasia and pyometra which could impair fertility for life. Therefore it is contraindicated to use progestogen based contraception in induced ovulators, vasectomise males, or to separate the sexes.

Please see below for a list of induced ovulators. If you are not sure whether an animal that you would like to treat is an induced ovulator or not, please contact EGZAC for more information at contraception@chesterzoo.org.

Induced ovulators:

  • All camelidae
  • All insectivora
  • All lagomorpha
  • Ferrets
  • Raccoons
  • Some felidae
  • Island fox (Urocyon littoralis)
  • Some ursidae (possibly American black bears, Ursus americanus)

 

Semi-induced ovulators:

  • Some rhino species e.g. the Sumatran rhinoceros, Diccerorhinus sumatrensis)