Repeated measures of ovulation rate on puberal heifers should be an effective way to select for increased twinning rate. A reliable estimate of the genetic correlation between ovulation and twinning rates is needed to implement such selection and to predict its efficiency. Restricted maximum likelihood was used to estimate genetic correlations from subsets of data collected from the twinning pr...

Concentrations of estradiol and progesterone in blood collected during the 12.5-day gestation period of the Virginia opossum were not significantly different from those during equivalent days of the estrous cycle. Progesterone was correlated with an index of corpora luteral mass. Ratio of estradiol to progesterone were highest 3 to 4 days before estrus and on the day of parturition.

Several investigators have suggested that the nucleic acid content of mouse liver varied with the estrus cycle. Nucleic acids were extracted with trichloroacetic acid and ethanol. The quantity of DNA and RNA was determined with a spectrophotometer. No significant differences were observed in the quantity of DNA or RNA throughout the estrus cycle. Diversity in the amount of nucleic acids present...

In Trial 1, 26 heifers were allotted randomly to a control group or one of four groups to receive a single injection of 3,000 IU hCG on d 1, 4, 7 or 10 of an estrous cycle. Heifers next completed a nontreated cycle, and at their third estrus were reallotted to one of the five groups described previously. Estrous cycle length was extended in cycle 1 but was not altered during the nontreated cycl...

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...

Twelve first-calf, 2-year-old, Hereford heifers were randomly assigned in equal numbers on two levels of energy (17.6 Meal DE/day and 11.4 Mcal DE/day) beginning 100 days prepartum. Jugular blood was collected three times weekly from the heifers starting 14 days before parturition, and continuing through the postpartum period until 20 days following the first estrus. There was no significant ef...

Ectonucleotide pyrophosphatase/phosphodiestrase 2 (Enpp2) isolated from the supernatant of human melanoma cells is a lysophospholipase D that transforms lysophosphatidylcholine into lysophospatidic acid. Although multiple analyses have investigated the function of Enpp2 in the hypothalamus, its role in the uterus during the estrous cycle is not well understood. In the present study, rat uterine...

Our objective was to study the effects of housing conditions and the amount of boar contact in a protocol for estrus detection on estrus detection rate, timing of onset of estrus, duration of estrus, and timing of ovulation. After weaning, 130 multiparous sows were assigned to three treatments: HI, in which 52 sows were housed individually in crates and received a high amount of boar contact du...

We examined 24p3 expression in the mouse uterus at various stages of the natural estrous cycle and during the preimplantation period. The level of 24p3 mRNA appeared intensively in proestrus and estrus, then declined sharply from metestrus to diestrus. Consistent with this observation, 24p3 protein was abundant in proestrus, decreased from estrus to metestrus and declined to a very low level in...

BACKGROUND/AIMS The pacemaker mechanisms activating phasic contractions of vaginal and cervical smooth muscle remain poorly understood. Here, we investigate properties of pacemaking in vaginal and cervical tissues by determining whether: 1) functional pacemaking is dependent on the phase of the estrus cycle or pregnancy; 2) pacemaking involves Ca2+ release from sarcoplasmic/endoplasmic reticulu...