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The biologist Thierry Lodé proposed (2001, 2012) five modes of reproduction based on the relationship between the zygote (fertilised egg) and the parents: [1] [2]. Ovuliparity: fertilisation is external, the oocytes being released into the environment and fertilised outside the body by the male. [1]
Female cattle, also referred to as "heifers" in agriculture, will gradually enter standing estrus, or "standing heat," starting at puberty between 9 and 15 months of age. The cow estrous cycle typically lasts 21 days. [5] Standing estrus is a visual cue which signifies sexual receptivity for mounting by male cattle.
Tritrichomonas foetus is a species of single-celled flagellated parasites that is known to be a pathogen of the bovine reproductive tract as well as the intestinal tract of cats. In cattle, the organism is transmitted to the female vagina and uterus from the foreskin of the bull where the parasite is known to reside.
[8] [9] Cattle breeds vary widely in size; the tallest and heaviest is the Chianina, where a mature bull may be up to 1.8 m (5 ft 11 in) at the shoulder, and may reach 1,280 kg (2,820 lb) in weight. [10] The natural life of domestic cattle is some 25–30 years. Beef cattle go to slaughter at around 18 months, and dairy cows at about five years.
A fresh cow is a dairy term for a cow (or a first-calf heifer in few regions) who has recently given birth, or "freshened." The adjective applying to cattle in general is usually bovine. The terms bull, cow and calf are also used by extension to denote the sex or age of other large animals, including whales, hippopotamus, camels, elk and elephants.
The mammalian female reproductive system contains three main divisions: the vagina and uterus, which act as the receptacle for the sperm, the ovaries, which produce the female's ova, and the vulva, which consists of the labia and clitoris. The vagina, uterus and ovaries are always internal while the vulva is external.
According to one preliminary study, the bulbourethral gland fluid might not contain any sperm, [10] whereas another study showed some men did leak sperm in potentially significant quantities (in a range from low counts up to 50 million sperm per ml) into the pre-ejaculatory fluid, [9] potentially leading to conception from the introduction of ...
The reproductive system of an organism, also known as the genital system, is the biological system made up of all the anatomical organs involved in sexual reproduction. Many non-living substances such as fluids, hormones , and pheromones are also important accessories to the reproductive system. [ 1 ]