Production calendars for most swine farms are based upon the reproductive cycle of sows and gilts. The key reproductive event that determines when females begin their reproductive cycles is the onset of estrus. Estrus normally occurs spontaneously in gilts and mature females that are not pregnant or lactating. Once estrous cycles have begun, they normally occur every 18 to 21 days. From a produ...

Story in Brief An extended interval from calving to first estrus in beef cattle may be associated with environmental stress and, suckling which increase the secretion of adrenocorticotropic hormone (ACT H) by the pituitary gland. Increased secretion of ACTH causes greater amounts of corticoids to be secreted by the adrenal gland. This experiment was designed to determine if treatment of anestro...

Instrumental sexual responses were investigated under conditions that the contact between the subjects was possible when both of them had accomplished the instrumental response. The instrumental responses were studied in three situations: (i) when the female subjects were in induced estrus, (ii) when they were in natural estrus, and (iii) in natural diestrus. The correlation between the male an...

A rapid return to estrus after weaning maximizes productivity in sow herds. Return to estrus is influenced by season and production factors (eg, parity and body condition).1-4 The effects of season and production factors on postweaning interval to estrus are mediated by ovarian follicular development.5,6 Sows with small follicles (< 4 mm) at day 3 after weaning were more likely to experience an...

Two experiments evaluated long-term progestin-based estrus-synchronization programs on the basis of potential for use in facilitating fixed-time AI in estrous cycling and prepubertal beef heifers. In Exp. 1, heifers were assigned to 1 of 2 treatments by age, BW, and estrous cyclicity status. Heifers assigned to the melengestrol acetate-PGF(2α) protocol (MGA-PG; n = 50) received MGA (0.5 mg·anim...

Hair sheep ewes were used to evaluate the influence of various levels of mating stimuli on the duration and timing of estrus and LH concentrations around estrus. Ewes were treated with PGF2alpha (15 mg, im) 10 d apart. At the time of the second PGF2alpha treatment (Day 0) ewes were placed in groups and exposed to different types of mating stimuli. One group of ewes (n = 16) was exposed to an ep...

to investigate the igg content and its variations in uterine fluid (uf) during the estrous cycle of the cow and to compare them with those of the blood serum (s), six pairs of serum and uf samples for each phase of the cycle selected out of 240 bovine genital tracts and blood samples were collected from urmia abattoir. the uf samples were collected by gentle scraping of the endometrium using a ...

in this study the reproductive organs of adult and apparently healthy female azarbaijan buffaloes werecollected after slaughter from abattoir. through observation of the ovaries, the luteal and follicular phases ofeach buffalo were specified. a total number of 36 oviducts at follicular phase and 36 oviducts at luteal phasewere collected and 3 tissue samples were taken from 3 regions of infundib...

BACKGROUND Prolonged pre-insemination anestrus (i.e. delayed puberty) is a major contributing factor for culling up to 30% of the replacement gilts at large breeding farm units in Vojvodina. It is imperative to determine if these gilts are acyclic (prepubertal) or cyclic, but just fail to exhibit behavioural estrus. Recent investigations demonstrate that treatment with equine chorionic gonadotr...

The present study was conducted on the Murrah buffaloes maintained at Livestock Research Centre of ICAR-National Dairy Research Institute (NDRI), Karnal. The animals were classified into heifer, primipara and pluripara. For this experiment a total of 50 Murrah buffaloes were followed, out of which 8 were heifers, 12 were primipara and 30 were pluripara. Daytime was considered to be from 6.00 am...