BACKGROUND During the estrous cycle, the rat uterine endometrium undergoes many changes such as cell proliferation and apoptosis. If implantation occurs, stromal cells differentiate into decidual cells and near the end of pregnancy, a second wave of apoptosis occurs. This process called decidual regression, is tightly regulated as is it crucial for successful pregnancy. We have previously shown...

Estrous synchronization and artificial insemination (AI) are reproductive management tools available to beef producers for over 30 years. Synchronization of the estrous cycle has the potential to shorten the calving season, increase calf uniformity, and enhance the possibilities for utilizing AI. Artificial insemination allows producers the opportunity to infuse superior genetics into their ope...

Twenty Simmental x Angus, half-sibling, postpubertal heifers (initial BW of 443 +/- 9 kg) were allotted randomly to 2 treatments to evaluate if initial BCS affects how heifers respond to energy restriction and repletion. Dependent variables of interest were changes in BW, BCS, and reproductive status [determined by concentrations of serum progesterone (P(4))]. Empty body composition (EBC) was c...

The aim of the study was to determine, in an experiment performed on conscious gilts, whether an increased amount of progesterone (P4) supplied to the porcine corpus luteum (CL), maintained within a physiological systemic concentration would influence its own secretion. On day 9 of the estrous cycle the jugular veins as well as both ovarian arteries and both ovarian veins were cannulated. In th...

Abstract Many taxa utilise chemosensation as their primary sensory modality and communicate with one another using pheromones. Sex-attractant pheromones facilitate mate location provide information regarding the reproductive status of potential mate. Snakes have adaptively radiated to many different habitats, some which preclude possibility depositing a continuous terrestrial pheromone trail (e...

To determine the influence of three levels of undegradable intake protein (UIP) supplementation on metabolic and endocrine factors that influence reproduction, 23 yearling crossbred heifers (body condition score = 4.5 +/- 0.5; initial BW = 362 +/- 12 kg) were stratified by BW and assigned randomly to one of three supplements: 1) low UIP (1,135 g x heifer(-1) x d(-1); 30% CP, 115 g UIP, n = 7); ...

The present study was designed to investigate the impact of exogenous administration of GnRH (Receptal VET®, Intervet Pharmaceuticals Ltd., India) on serum progesterone profile and conception rates during mid luteal phase of estrous cycle in buffaloes. Estrus was induced using Cyclix 2 mL. i/m. (Intervet India Pvt. Ltd., India) and animals were bred naturally during observed estrus. The buffalo...

i. Normative data from the anestrous, estrous, and post-estrous periods of females .. .275 2. The response of individual females to individual males 277 3. Behavior in the circle when females were in estrus . . . . 277 4. A comparison of present and previous mating preferences 28I 5. Behavior in the circle when females were in nonestrus 282 6. Temporal changes during estrus .. .282 7. Individua...

Intestinal calcium (Ca) absorption was measured under noninvasive conditions in both normally cycling and ovariectomized rats by determining the decrease in 47Ca/47Sc ratio between diet and feces. In 32-wk-old rats fed a 1.4% Ca diet, both fractional and total intestinal Ca absorption varied during the estrous cycle (p < 0.03), being highest during estrus and lowest during the second day of die...

Experiments designed for students in reproductive physiology are rare. Here, we describe a simple experiment concerning a physiological aspect of the reproductive system. Milk samples are obtained from cows in estrus, in midcycle, 21 days after insemination, and in gestation. With these samples, the gestation or estrous stage is determined according to the progesterone level in milk that is mea...