This experiment was designed to test the hypothesis that delayed insemination of nonestrous cows would increase pregnancy rates when using sex-sorted semen in conjunction with fixed-time artificial insemination (FTAI). Estrus was synchronized for 656 suckled beef cows with the 7-d CO-Synch + controlled internal drug release (CIDR) protocol (100 μg GnRH + CIDR [1.38 g progesterone] on d 0, 25 mg...

Molecular and intra-cellular mechanisms involved in the regulation of apoptosis processes in endometrial cells are poorly understood and documented. We have investigated the possibility that Akt survival pathway might be involved in the regulation of apoptosis in the uterus during the estrous cycle. Rats with regular estrous cycle (4 days) were killed at different days of estrous cycle (diestru...

To evaluate an artificial insemination program in postpartum Bos indicus cows and by using deterministic models, to estimate the possible economic advantages of insemination by appointment over detected estrus, sixty-three multiparous animals were synchronized using a progestagen device inserted at day 31 and withdrawn after 9 days (average time for withdrawal was 40.9 ± 6.8 days). Cows were ob...

Behavioral estrus of castrated and with progesterone treated ewes, induced by implantation of 17-beta-estradiol into the area controlling the sexual behavior, was completely modified as compared with that of castrated but non treated with progesterone ones. The length of behavioral estrus in the non treated ewes was 24-30 hr and its symptoms were rather weakly expressed. On the contrary, the ew...

BACKGROUND There is actually limited evidence about the influence of estrogens on neuronal energy metabolism or functional cerebral asymmetry. In order to evaluate this relationship, eight male and sixteen female adult Wistar rats, divided into estrus and diestrus phase, were used to measure basal neuronal metabolic activity in some of the structures involved in the Papez circuit, using cytochr...

Materials and methods: The study was performed in 5 groups of rat tracheal smooth muscle obtained during proestrus, estrus, metestrus, and diestrus phases of the estrous cycle, as well as the ovariectomized group (n:8/group). Cumulative acetylcholine contractions ranging from 10 to 10 M bath doses and the cumulative isoproterenol relaxations ranging from 10 to 10 M precontracted with 10 M of ac...

In this study, the response of female rats in different phases of the estrus cycle to nociceptive stimulation was evaluated using thermal (hot plate and tail immersion) and chemical (formalin) tests. In the hot plate test, the paw licking latency fell significantly (p < 0.05) in the metestrus and diestrus phases compared with the proestrus and estrus phases. The observations in the tail immersi...

The study comprises observations in 464 Swedish Yorkshire pigs at puberty and after the first weaning. The aim was to study relationships between age at puberty and weaning to estrus interval and between estrus signs at puberty and after the first weaning. The estrus signs were checked, and blood samples for progesterone determination were drawn regularly around puberty and after the first wean...

A study was conducted to evaluate the effect of a deficiency in dietary crude protein intake on postpartum reproductive performance of first-calf beef cows. Forty primigravid Hereford heifers were randomly assigned to two groups that were fed isocaloric (100% NRC requirements) diets containing .96 (adequate) or .32 (deficient) kg crude protein per head daily. Animals were individually fed from ...

Adult female New Zealand white rabbits with chronically implanted electrodes were used. Potentials (EVPs) were consistently evoked in the medial basal hypothalamus (MBH) including the median eminence and the arcuate nucleus by stimulation of the dorsal. hippocampus (HPC), medial amygdala (AMYG) and preoptic area (POA). These EVPs were variously influenced under endogenous or exogenous hormonal ...