The PMSG causes heat and ovulation. First signs of oestrus were observed 72 hr after cessation of treatment and 88-92% of animals treated within the breeding season came into oestrus within a week v 75% of animals treated out of season. Short-day breeders, such as sheep are sexually active in fall or winter. The high estradiol concentration is partially responsible for the ewe’s showing signs of estrus. Frequency of Cycles Species Difference Dogs. Oestrus is short in the cow, with ovulation occurring 10 to 12 hours after the end of oestrus. A female dog is dioestrous and goes into heat typically twice every year. To get good results, a period of progesterone priming is required. A cow standing to be mounted is the most accurate sign of estrus. This is an obligate parasite of the nasal and sinus cavities of sheep and goats. Sheep are seasonal breeders and ewes are stimulated to cycle by the declining daylight pattern in Autumn. Standing heat is the most sexually intensive period of the estrous cycle. ... Signs of oestrus in the ewe are not very obvious compared to cattle: The ewe will seek out a ram; Oestrus ovis. However, the sheep also must have been recently exposed to progesterone. Oestrus ovis (Diptera: Oestridae; nasal bot) is a brownish fly about the size of a honeybee that deposits its first-stage larvae in the nostrils of sheep in most areas of the world. Signs of Heat . The female deposits larvae in and about the nostrils of sheep … Primary sign. Long-day breeders, such as horses are sexually active in spring and summer. Sheep can be induced to cycle out of season with a treatment of progesterone followed by pregnant mare serum gonadotropin (PMSG). The adult fly is grayish brown and ~12 mm long. The sheep nose bot fly, Oestrus ovis, is a cosmopolitan parasite that, in its larval stages, inhabits the nasal passages and sinuses of sheep and goats. Clinical Signs: Infestation of the nasal bot (Oestrus ovis) in sheep and goats causes great irritation to the host animal. the fly Oestrus ovis (Diptera, Oestridae), that develops from the first to the third stage larvae. The Oestrus ovis larvae elicit clinical signs of cavitary myiasis seen as a seromucous or purulent nasal discharge, frequent sneezing, incoordination and dyspnea. The irritation is usually milder in goats than in sheep. Its geographic distribution is worldwide. It is essential to understand the primary and secondary signs of heat in order to achieve accurate and efficient heat detection. Female sheep reach puberty at about 6 months old, depending on breed and liveweight. Injections of 15 mg progesterone were given 6 times at 2-day intervals to 2200 breeding ewes in the normal breeding season (Aug.-Sep.) and to 2400 ewes out of season (Mar.-Apr.).