Biomedical subjects

B Kemp

Publications and source records attributed to B Kemp.

At least 37 records · Page 2Linked to original sources

PubMed2000

Effect of boar contact on follicular development and on estrus expression after weaning in primiparous sows.

Boar contact can induce ovarian activity, advance estrus and stimulate estrous behavior in sows. High amounts of boar contact can, however, suppress estrous behaviour. The present study with primiparous sows was designed to compare sows that had contact with a teaser boar during detection of estrus, with sows that had no boar contact at all. Number of sows detected in estrus within 9 d after weaning, onset and duration of estrus, follicular dynamics and timing of ovulation were studied. Boar contact increased the number of sows that ovulated and showed estrus from 14 of 47 to 24 of 47 (P < 0.05). Average timing of ovulation was later for sows with boar contact (165 h vs 150 h after weaning). Duration of estrus, detected without a boar, was similar in the two groups. For the sows with boar contact, duration of estrus detected with a boar was longer than estrus detected without a boar (56 vs 38 h; P < .01). Follicular dynamics were not affected by boar contact; boar contact only increased the number of sows with ovulation. Ovulatory sows showed a larger increase in follicular diameter (P < 0.01) from weaning to Day 4 after weaning (from 2.3 to 5.4 mm) than anovulatory sows (from 2.5 to 4 mm). Anovulatory sows did not show follicular growth after Day 4. It is concluded that boar contact can increase the number of sows that ovulate and show estrus after weaning. Estrous behavior does not seem to be suppressed by contact with a teaser boar, compared to sows without boar contact.

Animals↗

PubMed2000

Effect of superovulation induction on embryonic development on day 5 and subsequent development and survival after nonsurgical embryo transfer in pigs.

To evaluate the effects of eCG dosage on recovery and quality of Day 5 embryos and on subsequent development and survival after embryo transfer, batches of 5 to 10 donor sows were treated with 1000 or 1500 IU eCG. Recipients from the same batch were synchronously treated with 800 IU eCG. Ovulation was induced with 750 IU hCG (72 h after eCG) in donors and recipients. Donors were inseminated and embryos were collected at 162 h after hCG (120 h after ovulation). Ovulation rate was lower using 1000 IU eCG (28.5+/-11.7; n=48) than 1500 IU eCG (45.7+/-20.3; n=32; P<0.0001). Embryo recovery rate (82.9+/-16.9%) and percentage expanded blastocysts (56.2+/-31.4%) were similar (P>0.05). Expanded blastocysts from each group of sows were pooled into 2 groups within eCG treatment, containing embryos from normally ovulating sows (< or = 25 corpora lutea [CL]) or from superovulated sows (> 25 CL). Average diameter and number of cells of a random sample of the expanded blastocysts per pool were recorded. The average diameter of blastocysts (160.5+/-11.5 microm) was not affected by eCG dosage or ovulation rate (P>0.10). The average number of cells per embryo was higher in the 1000 IU eCG group (84.3+/-15.3) than in the 1500 IU eCG group (70.2+/-1.9; P<0.05) but was similar for normal and superovulated donors within each eCG group (P>0.10). Of the 4 groups, litters of 28 to 30 blastocysts were nonsurgically transferred to 27 synchronous recipients. Pregnant recipients were slaughtered on Day 37 after hCG treatment to evaluate embryonic development and survival. Pregnancy rate for the 1000 and 1500 IU eCG donor groups was 71% (10/14) and 46% (6/13; P>0.10), respectively. The number of implantations and fetuses for the 1000 IU eCG groups was 12.9+/-3.0 and 11.1+/-2.7, and 14.2+/-7.0 and 10.5+/-4.6, respectively, for the 1500 IU eCG groups (P>0.10). After post-priory categorizing the litters of blastocysts to below or above the average diameter (158 microm) of the transferred embryos, irrespective of eCG dosage or ovulation rate, the pregnancy rate was 43% (6/14) and 77% (10/13; P<0.10), respectively. Post-priory categorizing the transferred litters to below or above the average number of cells per embryo litter, irrespective of eCG dosage or ovulation rate, showed no differences in pregnancy rates or number of implantations and fetuses (P>0.10). It was concluded that eCG dosage affects embryonic development at Day 7 after hCG, and this effect was not due to ovulation rate. Embryonic survival after nonsurgical transfer was not related to eCG dosage but tended to be related to the diameter of the blastocysts.

Animals↗

PubMed2000

Timing of insemination relative to ovulation in pigs: effects on sex ratio of offspring.

The objective of the present study was to identify effects of the interval between insemination and ovulation in pigs on the sex ratio and sex ratio dispersion of offspring. Crossbred sows that had farrowed 2 to 9 litters were weaned (Day 0) and came into estrus between Days 3 and 7 after weaning. Ultrasonography was performed every 6 h, from 12 h after the onset of estrus until ovulation had been observed. The sows were inseminated once at various intervals from the onset of estrus. At farrowing, the numbers of viable piglets and dead piglets were recorded per sow. In four 12-h intervals between insemination and ovulation (36 to 24 h before ovulation, 24 to 12 h before ovulation, 12 to 0 h before ovulation and 0 to 12 h after ovulation), the total number of piglets was (mean+/-SEM) 10.8+/-1.2 (n=15); 13.4+/-0.7 (n=23); 13.2+/-0.9 (n=21); and 12.1+/-1.0 (n=16), respectively (P>0.05). The percentage of male piglets per litter in the four 12-h intervals was 52.1+/-3.6, 50.5+/-2.7, 54.9+/-2.8 and 47.8+/-4.5, respectively (P>0.05). Sex ratio was not influenced by litter size (P>0.05), and its distribution was normally dispersed (i.e., as expected under a binomial distribution) in all 4 intervals between insemination and ovulation (P>0.05).

Animals↗

PubMed2000

Effects of different reproduction techniques: AI MOET or IVP, on health and welfare of bovine offspring.

Since the introduction of in vitro production (IVP) of bovine and sheep pre-implantation embryos, increased birth weights and other deviations of IVP calves and lambs compared with AI or MOET offspring have been reported. Study 1 of the present paper, a comparison between AI, MOET and IVP (co-culture/serum) calves with respect to calf and calving characteristics in large-scale field conditions, confirms these reports. In addition, it is shown that MOET calves tend towards higher birth weights and have significantly longer gestations and more difficult calvings than AI calves. It is presently unknown if the effect of IVP is also observed later in life. In this paper, data on reproduction characteristics of bovine IVP co-culture/serum offspring are presented. Semen production--and non return data of one year old IVP bulls and superovulation-, AI- and OPU/IVP results of one year old IVP heifers are compared with those of one year old AI and MOET animals producing semen or embryos in the same time period. So far, there are no indications that the use of IVP is reflected in deviate reproduction characteristics of bovine IVP offspring. It has been suggested that use of co-culture cells and serum during in vitro culture of bovine (and sheep) embryos may partially explain the increased birth weights and other deviations of bovine and sheep IVP offspring. Deletion of these factors in semi-defined culture media, e.g. Synthetic Oviductal Fluid (SOF), could result in more normal offspring. Study 2 investigates this hypothesis in both field conditions (Study 2a, comparing AI, IVP co-culture/serum and IVP SOF calves) and in semi-standardized conditions (Study 2b, comparing MOET, IVP co-culture/serum and IVP SOF calves at one herd). In Study 2a, although IVP SOF calves showed (non-significant) shorter gestations, easier calvings and lower percentages of perinatal mortality and congenital malformations than IVP co-culture calves, birth weights were not decreased. In Study 2b however, the difference between IVP co-culture and IVP SOF calves in birth weight and ease of calving was significant (P < 0.05), IVP SOF calves resembling MOET calves more. IVP calves differed significantly from MOET calves with respect to several physiological parameters, such as blood oxygen saturation level, heart beat frequency and some measures of the heart. In addition, in Study 2b, recipients receiving an IVP SOF embryo showed a more regular return to estrus than those receiving an IVP co-culture embryo. From Study 2 it can be concluded that using a semi-defined medium for in vitro culture (SOF) may improve characteristics of IVP calves born.

Animals↗

PubMed2000

Environment of oocyte and embryo determines health of IVP offspring.

In vitro embryo production (IVP) enhances the number of offspring from a single female and offers the possibility of accelerated genetic progress in animal husbandry. However, it also leads to a low but unacceptable percentage of anomalies in the offspring. The aim of this paper is to introduce the three speakers at this afternoon session who will speak about the demands of culture conditions and the endometrial environment to support normal embryonic development without effects on the embryonic genome. It will be argued that the in vitro conditions should mimic precisely the oviductal contributions to homeostatic mechanisms within the embryo. The further normal development can be guaranteed at synchrony in development of both endometrium and embryo. If that is not the case one can expect disturbances of gene expression, in particular of imprinted genes. However, it cannot be excluded that some processes might have started already in the cytoplasm of the oocyte. Since the oocyte was not planned to be a separate subject in this symposium, this introduction is also aimed to ask attention for the selection of cumulus-oocyte-complexes (COCs) and the conditions around oocyte maturation in vitro. The optimal quality of both the oocyte and maturation medium are prerequisites for an undisturbed cytoplasmic maturation. It has been argued that the exclusion of COCs from atretic follicles, the abjuration of the use of serum and high O2 tension in the gas phase might help to reduce the proportion anomalies in the offspring after synchronous transfers. In human IVF, in vivo matured oocytes are used with no great problems. But before IVP, including oocyte maturation in vitro (IVM) and a longer lasting embryo culture (IVC), will be introduced into the human assisted reproduction, it is important to think about the ins and outs of the potential causes for deviations.

Animals↗

PubMed2000

Induction of labor by prostaglandin E(2) in relation to the Bishop score.

OBJECTIVE: To compare the effectiveness of prostaglandin E(2) intravaginal gel with the intracervical gel in patients with an unfavorable cervix. METHOD: In a prospective multicenter trial 470 patients with unfavorable Bishop scores (3-4) were randomized to receive prostaglandin vaginal gel (2 mg) or intracervical gel (0.5 mg). RESULTS: In patients with unfavorable Bishop scores the intravaginal application route resulted in a better cervical ripening, a shorter induction to delivery interval and a higher cumulative rate of deliveries during 24 h (P=0.01). CONCLUSION: Intravaginal instillation of prostaglandin E(2) gel for induction of labor is effective in patients with an unfavorable Bishop score of 3-4.

Administration, Intravaginal↗

PubMed2000

Tissue concentrations of endothelial cell adhesion molecules in the lower uterine segment during term parturition.

OBJECTIVE: To determine the concentration of endothelial cell adhesion molecules in the lower uterine segment during parturition at term. METHODS: We analyzed protein extracts from the lower uterine segments of 38 women who had nonelective cesareans at term. We measured concentrations of intercellular adhesion molecule-1, endothelial leukocyte adhesion molecule-1, vascular cell adhesion molecule-1, and platelet endothelial cell adhesion molecule-1 by enzyme-linked immunosorbent assay. Subjects were grouped according to cervical dilatation (less than 2 cm, n = 10; 2 to less than 4 cm, n = 9; 4-6 cm, n = 9; more than 6 cm, n = 10) and duration of labor (up to 6 hours, n = 14; 6-12 hours, n = 10; 12-24 hours, n = 9; longer than 24 hours, n = 5) at the time of cesarean. RESULTS: The median concentration of intercellular adhesion molecule-1 increased significantly with increasing dilatation (from 2.24 ng/mg total protein at less than 2 cm to 6.73 ng/mg at 4-6 cm) and increasing duration of labor (from 2.53 ng/mg up to 6 hours to 5.90 ng/mg at 12-24 hours). However, this study did not have adequate statistical power to identify differences in concentrations of the other endothelial adhesion molecules. CONCLUSION: The results indicate that parturition at term is associated with expression of intercellular adhesion molecule-1.

Adult↗

PubMed2000

9:15-9:30. A Clinical Evaluation of Segmented Attenuation Correction.

Segmented attenuation correction (SAC) has been introduced as a method of reducing transmission scan times without degrading the quality of PET images. Presented are the results of a clinical evaluation of a SAC algorithm implemented on the GE Advance PET system. FDG whole body patient emission scans of eight minute duration were acquired. Dynamic transmission (Tx) scans of 5 frames and 6 minute total duration were acquired and rebinned into Tx scans of 2, 3, 4, 5 and 6 minute duration. Images (I) were generated using iterative reconstruction with measured attenuation correction (MAC) or SAC for all Tx scans-denoted as I(Tx6MAC), I(Tx6SAC), etc. Anthropomorphic phantom data was also acquired and reconstructed using the same methodology. Images were evaluated quantitatively using the normalized mean square error (NMSE) of different regions and the variance and bias of liver activity. I(Tx6MAC) served as the reference. A blinded observer ranked image quality. The NMSE increased as the Tx duration decreased; for patient images the NMSE was typically 20% and 40% greater for I(Tx3SAC) and I(Tx2SAC) than I(Tx6SAC) respectively. The NMSE of the MAC images increased much more rapidly as the Tx duration decreased. Similar trends were found for the variance in the liver. Bias in liver activity of the SAC images was approximately -8% for large patients. The observer consistently preferred SAC images over MAC images. SAC images demonstrated improved boundary delineation and reduced noise in areas of homogeneous high activity background. Areas of discordance were projected into areas of large difference between Tx and segmented Tx sinograms. This study has validated the use of SAC with short Tx scans. Images reconstructed with Tx scans of 3 minutes were not compromised with noise or severe artifacts.

Journal Article↗

PubMed2000

Depression after spinal cord injury: relation to gender, ethnicity, aging, and socioeconomic indicators.

OBJECTIVE: To investigate the relation among aging, gender, ethnicity, socioeconomic indicators, and depressive symptoms after spinal cord injury (SCI). DESIGN: Survey was done to collect cross-sectional data. A mediational model was used to analyze the interrelationships between predictors and depressive outcome variables. SETTING: A large Southeastern rehabilitation hospital. PARTICIPANTS: Participants, identified from outpatient records who met the following inclusion criteria: (1) traumatic SCI; (2) at least 18 years old at the time of study; and (3) injured for at least 1 year. There was an initial pool of 1923 potential participants in 1997, of whom 1391 (72%) participated. MAIN OUTCOME MEASURES: The Older Adult Health and Mood Questionnaire, a 22-item measure of depressive symptoms designed following Diagnostic and Statistical Manual of Mental Disorders (DSM III-R) criteria, was used to measure depression. It has been validated against clinical assessments by psychiatrists and psychologists. RESULTS: Forty-eight percent of the participants reported clinically significant symptoms. Minority participants, particularly women, were at a substantially higher risk for depressive symptoms. This risk diminished but did not disappear after controlling for years of education and income, both of which were highly negatively correlated with depressive symptoms. Aging factors were modestly positively correlated with depression, although education or income did not mediate these associations. CONCLUSIONS: Symptoms of depression are highly prevalent after SCI and are related to aging, gender or ethnicity, and socioeconomic status indicators (education and income).

Adolescent↗

PubMed2000

The human placenta is encircled by a ring of smooth muscle cells.

The marginal zone of the human term placenta was studied by transmission electron microscopy and immunohistochemistry using antibodies against cytoskeletal filaments, extracellular matrix molecules and endothelial markers. The marginal sinus of the intervillous space is separated from the chorionic and basal plates by a layer of cells expressing vimentin, desmin, alpha- and gamma-smooth muscle actins, and smooth muscle myosin. Also ultrastructurally, these cells share all features with smooth muscle cells. This muscular ring is continuous with the media of uteroplacental veins entering the marginal sinus. In the basal plate the muscle cells may extend far into the central parts of the placenta. The muscular ring is separated from the intervillous space by a layer of endothelial cells. They are continuous with the maternal endothelium of the marginal uteroplacental veins. Moreover this endothelium covers neighbouring parts of the chorionic and basal plates, locally extending to the surfaces of large stem villi. The data suggest (1) that the marginal zone of the intervillous space ('marginal sinus') represents the dilated and merged parts of uteroplacental veins and (2) that lateral growth of the human placenta partly takes place by expansion into the uteroplacental veins. The functional importance of this muscular ring remains unknown.

Actins↗

PubMed2000

Pregnancy-induced de-differentiation of media smooth muscle cells in uteroplacental arteries of the guinea pig is reversible after delivery.

The majority media of smooth muscle cells of uteroplacental arteries of the guinea pig is not destroyed during trophoblast invasion. Rather, most of these cells de-differentiate during pregnancy-induced arterial dilatation, forming a population of mesenchyme-like myoblasts ready to reconstitute the media after birth. We have studied the re-differentiation of these cells after delivery by means of transmission electron microscopy and immunohistochemistry using antibodies against a panel of cytoskeletal proteins. The data reveal that post partum re-differentiation of the media myoblasts starts immediately after birth where some of the invasive trophoblast cells are still present. The process of re-differentiation is completed at day 8 after parturition. Post partum re-differentiation can be subdivided into two steps: until day 5 after parturition, the central parts of the media are reconstituted out of the reservoir of vimentin-positive myoblasts by stepwise acquisition of desmin, alpha-smooth muscle actin, gamma-smooth muscle actin and smooth muscle myosin. Only thereafter the same re-differentiation takes place in the peripheral parts of the media. On the ultrastructural level immunohistochemical re-expression of cytoskeletal proteins is accompanied by reconstitution of the intracellular contractile apparatus. The data support our earlier notion that the majority of media smooth muscle cells in the guinea pig uterus does not degenerate during trophoblast-invasion but rather de-differentiate temporarily.

Animals↗

PubMed2000

A pharmacodynamic Markov mixed-effects model for the effect of temazepam on sleep.

BACKGROUND: A hypnogram shows how sleep travels through its various stages in the course of a night. The sleep stage changes can be quantified to study sedative drug effects. METHODS: Hypnograms from 21 patients with primary insomnia were collected during a randomized, placebo-controlled crossover study of 20 mg temazepam. A separate daytime session was performed to determine the pharmacokinetics of 20 mg temazepam and its effect on saccadic eye movement and electroencephalogram. A first-order Markov model was developed to describe the probability of sleep stage changes as a function of time after drug intake and time after last sleep stage change. The influence of temazepam concentration on the probability to change sleep stage was incorporated into the model. RESULTS: Transitions between sleep stages were profoundly influenced by the time of the night and by the time since the last change of sleep stage. Temazepam reduced the time spent awake. This effect could be attributed to four mechanisms: (1) transition to "deeper" sleep was facilitated, (2) transition to "lighter" sleep was inhibited, (3) regardless of sleep stage, the transition to wake state was inhibited, and (4) return to sleep was facilitated. Daytime sensitivities to temazepam, measured with the surrogate markers saccadic peak velocity and electroencephalogram beta activity, each correlated with one of the transition probabilities influenced by temazepam. CONCLUSIONS: By the development of a Markov model for these non-ordered six categorical data, the effect of temazepam on the sleep-wake status could be interpreted in terms of known mechanisms for sleep generation and benzodiazepine pharmacology.

Adolescent↗

PubMed2000

Analysis of a sleep-dependent neuronal feedback loop: the slow-wave microcontinuity of the EEG.

Increasing depth of sleep corresponds to an increasing gain in the neuronal feedback loops that generate the low-frequency (slow-wave) electroencephalogram (EEG). We derived the maximum-likelihood estimator of the feedback gain and applied it to quantify sleep depth. The estimator computes the fraction (0%-100%) of the current slow wave which continues in the near-future (0.02 s later) EEG. Therefore, this percentage was dubbed slow-wave microcontinuity (SW%). It is not affected by anatomical parameters such as skull thickness, which can considerably bias the commonly used slow-wave power (SWP). In our study, both of the estimators SW% and SWP were monitored throughout two nights in 22 subjects. Each subject took temazepam (a benzodiazepine) on one of the two nights. Both estimators detected the effects of age, temazepam, and time of night on sleep. Females were found to have twice the SWP of males, but no gender effect on SW% was found. This confirms earlier reports that gender affects SWP but not sleep depth. Subjectively assessed differences in sleep quality between the nights were correlated to differences in SW%, not in SWP. These results demonstrate that slow-wave microcontinuity, being based on a physiological model of sleep, reflects sleep depth more closely than SWP does.

Adolescent↗

PubMed2000

Optimal excitation wavelengths for in vivo detection of oral neoplasia using fluorescence spectroscopy.

There is no satisfactory mechanism to detect premalignant lesions in the upper aero-digestive tract. Fluorescence spectroscopy has potential to bridge the gap between clinical examination and invasive biopsy; however, optimal excitation wavelengths have not yet been determined. The goals of this study were to determine optimal excitation-emission wavelength combinations to discriminate normal and precancerous/cancerous tissue, and estimate the performance of algorithms based on fluorescence. Fluorescence excitation-emission matrices (EEM) were measured in vivo from 62 sites in nine normal volunteers and 11 patients with a known or suspected premalignant or malignant oral cavity lesion. Using these data as a training set, algorithms were developed based on combinations of emission spectra at various excitation wavelengths to determine which excitation wavelengths contained the most diagnostic information. A second validation set of fluorescence EEM was measured in vivo from 281 sites in 56 normal volunteers and three patients with a known or suspected premalignant or malignant oral cavity lesion. Algorithms developed in the training set were applied without change to data from the validation set to obtain an unbiased estimate of algorithm performance. Optimal excitation wavelengths for detection of oral neoplasia were 350, 380 and 400 nm. Using only a single emission wavelength of 472 nm, and 350 and 400 nm excitation, algorithm performance in the training set was 90% sensitivity and 88% specificity and in the validation set was 100% sensitivity, 98% specificity. These results suggest that fluorescence spectroscopy can provide a simple, objective tool to improve in vivo identification of oral cavity neoplasia.

Algorithms↗

PubMed2000

[Fatality rate in the epidemiology of meningococcal disease: study in the region of Campinas, SP, Brazil, 1993 to 1998].

OBJECTIVE: To analyze the trends of the meningococcal disease cumulative incidence and case-fatality rate in the region of Campinas, Brazil, an area that encircles five cities and 1.2 million inhabitants, from 1993 to 1998. METHODS: A longitudinal retrospective study of all case records (375) obtained from the regional epidemiological surveillance system was carried out. A logistic regression analysis allowed identifying the risk factors related to fatal outcomes of meningococcal disease. RESULTS: The highest fatality rates (23.8%) were seen in the period of 1996 and 1997, coinciding with the incidence peaks of serogroup B Neisseria and a high percentage of septicemia cases. Also at the same period there was registered a poor etiological investigation of the cases. A seasonal pattern and the predomination of strains B:4:P1.15 and C:2b:P1.3 were observed. In the logistic regression analysis, the risk factors related to fatality were: septicemia with or without meningitis (adjusted odds ratio [OR(aj)] = 13.88 and 95% confidence interval [CI] = 4.68 - 42.13); age over 30 years (OR(aj) = 6.42; CI = 2.32 - 17.80); age under 1 year (OR(aj) = 2.95; CI = 1.55 - 5.63); and serogroup B (OR(aj) = 2.33; CI = 1.14 - 4.79). CONCLUSIONS: Septicemia, age and serogroup were predictive variables related to a fatal outcome. In 1996 and 1997, case-fatality rates were high, indicating the need to further assessment of the quality of the services delivered and their readiness to take preventive action. The lack of etiological identification in many cases precluded more accurate inferences about the epidemiological behavior of Neisseria meningitidis in the region.

Adolescent↗

PubMed2000

Responsiveness to boar stimuli and change in vulvar reddening in relation to ovulation in weaned sows.

In 117 weaned sows, changes in estrous behavior and vulvar reddening were related to timing of ovulation. Detection of estrus was performed every 8 h with four levels of boar stimuli to record the change in responsiveness to these stimuli. This resulted in four overlapping phases of estrus, during which a standing response could be evoked: 1) man estrus (standing response to a back pressure test, in the absence of a boar), 2) spontaneous estrus (standing response in the presence of a boar, no back pressure test), 3) boar estrus (standing response to boar + back pressure test), and 4) detection-mating-area estrus (back pressure test in the presence of four boars). In addition to the detection of estrus, the change in reddening of the inner vulvar mucosa was recorded. Manifestation of estrus in response to the four stimuli occurred in 46, 56, 90, and 97% of the sows, respectively. Onset of the four phases occurred 24 h (SD 13 h), 23 h (SD 15 h), 34 h (SD 13 h), and 41 h (SD 12 h) before ovulation. The duration of the intervals between the various phases of estrus explained 10 to 50% of the variation in the timing of ovulation relative to the onset of the phases. However, these intervals could not be calculated for all sows because estrus was not expressed at every stimulus level by each sow. The end of vulvar reddening occurred, on average, 21 h (SD 14 h) before ovulation. Except for five sows that ceased to show vulvar reddening within 5 h after ovulation, the end of vulvar reddening occurred before ovulation, within a 70-h range. Of the sows showing boar estrus, 90% also showed vulvar reddening. For sows that showed vulvar reddening until after the onset of boar estrus (two-thirds of the sows), the end of reddening occurred within a much smaller range: from 36 h before, until 2 h after, ovulation. Onset of estrus, regardless at which stimulus level it is detected, appears too variable relative to timing of ovulation to be used as a predictor for ovulation. Duration of the different stages of responsiveness explains only some of this variation and cannot be obtained on all sows. Combining information on vulvar reddening and boar estrus can predict ovulation within a reasonable range for two-thirds of the sows.

Animals↗

PubMed2000

Dietary energy source at two feeding levels during lactation of primiparous sows: I. Effects on glucose, insulin, and luteinizing hormone and on follicle development, weaning-to-estrus interval, and ovulation rate.

Our objective was to study the effects of dietary-induced insulin enhancement during and after lactation on the reproductive performance of primiparous sows. During a 21-d lactation period, 48 sows were allotted to a 2x2 factorial experiment. Treatments were feeding level (high or low; 44 MJ or 33 MJ NE/d) and dietary energy source (fat or starch). After weaning, all sows received the same amount of feed (31 MJ NE/d from weaning to estrus and 17.5 MJ NE/d from breeding until slaughter) of the same energy source as fed during lactation. On d 7, 14, and 21 of lactation and d 22 (weaning), blood samples were taken every 12 min for 12 h and analyzed for plasma glucose, insulin, and LH. Sows were slaughtered on d 35 of the subsequent pregnancy, and ovulation rate was assessed. During lactation, postprandial plasma glucose and insulin concentrations were higher for sows fed the starch diet than for those fed the fat diet (P<.001), whereas feeding level had no effect. Basal and mean LH concentrations were not affected by treatments. The LH pulse frequency on d 7 of lactation was greater for sows fed the starch diet than for those fed the fat diet (.52 vs .17 pulses/12 h; P = .03). The high compared with the low feeding level resulted in a greater LH pulse frequency on d 21 of lactation (.89 vs .47 pulses/12 h; P = .05) and on d 22 (8.63 vs 5.77 pulses/12 h; P = .02), in a higher percentage of sows that exhibited estrus within 10 d after weaning (96 vs. 63%; P = .01), and a tendency for a higher ovulation rate (18.0 vs. 16.2; P = .09). Plasma glucose and insulin concentrations were not related to any of the LH traits. The LH pulse frequency after weaning was related to the weaning-to-estrus interval (WEI) and was best explained by a linear-plateau model. In sows fed the low feeding level, follicle size after weaning was correlated with LH pulse frequency after weaning and with the WEI, whereas in sows fed the high feeding level these correlations were not significant. Our results indicate that an improved dietary-induced insulin status during and after lactation does not overcome the inhibitory effects of lactation on subsequent reproduction at any of the feeding levels.

Animal Feed↗

PubMed2000

Dietary energy source at two feeding levels during lactation of primiparous sows: II. Effects on periestrus hormone profiles and embryonal survival.

Our objective was to study the effects of dietary energy source (fat or starch) on periestrus hormone profiles and embryonal survival in primiparous sows. During lactation, 48 primiparous sows were fed either a starch-rich or a fat-rich diet, at either a high (44 MJ NE/d) or a low (33 MJ NE/d) feeding level. After weaning, all sows received the same amount of feed (31 MJ NE/d from weaning to estrus and 17.5 MJ NE/d from breeding to slaughter) of the same dietary energy source fed during lactation. Around estrus, blood samples were taken to analyze the preovulatory LH surge, estradiol (E2), and progesterone (P4). Sows were inseminated on each day of standing estrus. On d 35 after last insemination, all 35 pregnant sows were slaughtered and their reproductive tracts were removed. The number, weight, and length of the embryos and placentas were determined as well as the weight and length of the uterus. The LH, E2, and P4 profiles were similar for the treatment groups, except for the E2 levels at 16, 12, and 8 h before the LH surge, which were lower in the sows fed the fat-rich diet at a low level. Ovulation rate tended to be higher in sows fed the high compared to the low feeding level during lactation (18.0 vs. 16.2; P = .09), but the number of total and viable embryos as well as embryonal survival rate were not influenced by the treatments. Neither uterine length and weight nor length and weight of the embryos and placentas were affected by treatments. However, after removal of the embryo-placental units, uterine weight was greater in sows fed the high than in those fed the low feeding level during lactation (1.8 vs. 1.6 kg; P = .03). Plasma insulin concentration during lactation was not related to any of the uterine, placental, or embryo traits. Mean progesterone concentration between 24 and 250 h after the LH surge was positively correlated with embryonal survival. Differences in progesterone concentration between sows with high and low embryonal survival were evident from 172 h after the LH surge. From the present study, we conclude that altering feeding level during lactation or dietary energy source from farrowing until d 35 of subsequent pregnancy did not affect embryonic development and embryonal survival.

Animal Feed↗