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At least 649 records · Page 36Linked to original sources
PubMed1999

Effects of twinning on postpartum reproductive performance in cattle selected for twin births.

The effects of twinning, dystocia, retained placenta, and body weight on postpartum reproduction were evaluated for 3,370 single and 1,014 twin births. Females were bred by AI for 40 d followed by 20 or 30 d of natural service with equal numbers bred and calved in spring and fall. Percentage of dams cyclic by the end of the AI period was lower (P<.05) for dams birthing and nursing a single calf (92.4%) than for dams birthing twins and nursing zero (98.7%) or two (94.7%) calves. Whereas the interval from parturition to first estrus was shorter (P<.01) for dams birthing and nursing a single (56.9 d) than for dams birthing twins and nursing one (68.5 d) or two (69.6 d) calves, length of the interval was further reduced by dystocia in nonlactating dams of either twins or singles (type of birth x dystocia, P<.05). Ensuing pregnancy rates were also affected by type of birth and dystocia. Without dystocia, dams birthing and nursing a single calf had a higher pregnancy rate (79.2%) than dams birthing twins and nursing one (61.7%) or two (66.3%) calves, whereas the lower ensuing pregnancy rates associated with dystocia in dams of singles (71.9%) resulted in similar rates among dams of singles and twins with dystocia (type of birth x dystocia; P<.01). Having a retained placenta resulted in a lower incidence of (93.5 vs. 96.4%, with vs. without; P<.05) and a longer interval to (64.7 vs. 59.2 d; P<.01) estrus while reducing subsequent pregnancy rates (X = 9.6%) in 3 of the 7 yr evaluated (retained placenta x year, P<.01). Because all parous females were bred during the same calendrical period, the shorter gestation length for twin calves (275.6 vs. 281.3 d) resulted in a longer interval from parturition to conception for twin births, whereas means for conception date differed by only 2 d between dams of twins and singles. Furthermore, a reduction (P<.01) in the interval to conception occurred with dystocia in dams of singles (89.3 vs. 85.0 d, without vs. with dystocia) and of twins nursed by zero (116.9 vs. 83.5 d), one (100.2 vs. 92.8 d), or two (96.1 vs. 97.2 d) calves. Another detriment to fertility was the higher incidence of fetal mortality or abortions associated with twin vs. single pregnancies (12.4 vs. 3.5%; P<.01). However, despite the lower conception rates for dams of twins, the increased prolificacy provides an opportunity to increase total beef production with a twinning technology.

Animals↗
PubMed1985

The effect of repeated mating at short intervals on reproductive performance of gilts.

Three trials involving 87 gilts were completed to investigate the role of additional sexual stimulation on various reproductive parameters. Forty-five gilts were mated twice at 12-h intervals at second pubertal estrus with intact boars beginning 12 h after detection of sexual receptivity (control group). Forty-two gilts were exposed to a vasectomized boar 15 min following each fertile mating to provide additional copulatory stimulus (treatment group). This additional exposure improved (P less than .01) conception rate (100 vs 84%). No statistical differences were observed in number of corpora lutea (CL), number of viable embryos (VE) or number of total embryos (TE) at d 30. These results suggest that additional mating stimuli may have a beneficial effect on conception rate. While the use of additional males resulted in more pregnant females, it likely did not have an effect on litter size.

Animals↗
PubMed2002

Reproductive performance of dairy cows with ovarian cysts after different GnRH and cloprostenol treatments.

Cystic ovarian disease is an important cause of reproductive failure and economic loss for the dairy industry. This report describes two consecutive studies. The objective of the first was to evaluate the response of cows with ovarian cysts to two therapeutic treatments. In the second study, we compared the effectiveness of the best treatment established in Study 1 with that of the Ovsynch protocol. For Study 1, cows were considered to have an ovarian cyst if it was possible to observe a single follicular structure with a follicular antrum diameter > 25 min in the absence of a corpus luteum in three ultrasonographic examinations performed at 7 days intervals. At diagnosis (Day 0), cows were assigned to one of two treatment groups. Cows in Group GnRH/CLP (n = 31) were treated with 100 microg GnRH i.m. and 500 microg cloprostenol (CLP) i.m. on Day 14. Cows in Group GnRH-CLP/CLP(n = 32) were treated with 100 microg GnRH i.m. plus 500 microg CLP i.m. on Day 0, and 500 microg CLP i.m. on Day 14. The animals were inseminated at observed estrus and monitored weekly by ultrasonography for 4 weeks or until Al. Cows in the GnRH-CLP/CLP group showed a lower cystic persistence rate (15.6% < 45.2%; P = 0.01); a higher estrus detection rate (84.4% > 41.9%; P < 0.0001); a higher ovulation rate (75% versus 32.3%; P < 0.0001) and a higher early response rate (31% > 3%; P = 0.02) than those in the GnRH/CLP group. For the second study, 128 cows with ovarian cysts were randomly assigned to one of two treatment groups: cows in Group Ovsynch (n = 64) were treated with 100 microg GnRH i.m. on Day 0, 500 microg CLP on Day 7, and 100 microm GnRH i.m. 36 h later. Cows in this group were inseminated 24 h after the second GnRH dose (Ovsynch protocol). Cows in Group GnRH-CLP/CLP/GnRH (n = 64)were treated as those in the GnRH-CLP/CLP group of Study 1 but received GnRH 32 h after the second CLP treatment and were inseminated 24 h after this. A further group of cows without ovarian cysts inseminated at natural estrus served as the Group Control (n = 64). Cows in the GnRH-CLP/CLP/ GnRH group showed a lower cystic persistence rate (10.9% < 46.9%; P < 0.0001); higher ovulation rate (79.7% > 17.2%; P < 0.0001); higher return to estrus rate (34.3% > 12.5%; P < 0.01) and higher pregnancy rate (28.1% > 3.1%; P < 0.01) than those in Ovsynch; and a similar pregnancy rate (28.1% versus 35.9%) to Control cows. These findings indicate that lactating cows with ovarian cysts can be successfully synchronized and time inseminated using a protocol that combines GnRH and CLP, starting treatment by simultaneously administering both products. This protocol also allows the insemination of cows showing estrus within the first week of treatment. Ovarian cysts were less responsive when treatment was started with GnRH alone.

Animals↗
PubMed1992

Studies on the reproductive performance of Ethiopian sheep by means of an enzyme immunoassay technique; a review.

Measurement of the concentration of hormones associated with reproductive function in female animals can aid in the evaluation of their reproductive status. In particular, from the point of view of production, determination of the concentration of circulatory progesterone can aid in the correct assessment of ewes. Many investigators have used radioimmunoassay for this purpose, but the enzyme-linked immunosorbent assay (ELISA) is equally reliable, quicker and cheaper. This report reviews the use of the ELISA in Ethiopian Menz sheep. Progesterone profiles in Ethiopian Menz sheep during pubertal development, the oestrous cycle, pregnancy and post-partum anoestrus were similar to those of temperate breeds. The practical applications of progesterone determination to sheep production and the requirement for the correct handling of samples are emphasized.

Animals↗
PubMed1985

Energy intake, body composition and reproductive performance of the gilt.

The relationship between age, live weight, body composition and energy status on the onset and maintenance of reproductive activity in females is reviewed. When possible, swine studies have been employed, although, of necessity, much data are drawn from other species. The relationship between age, weight and puberty is controversial. However, from the available data we conclude that neither age nor weight are reliable indices of reproductive development, but that minimum threshold values for these characteristics must be achieved before puberty can occur. Human data provides a strong indication that a minimum adipose to lean tissue ratio is a prerequisite for puberty onset. Limited data from swine support this contention and indeed it may be a superior measure of reproductive development than either age or weight. However, the value of this ratio remains to be defined in pigs, and again it is minimum threshold level, the attainment of which is necessary, but not in itself sufficient, for puberty onset. A positive energy balance seems to be necessary for puberty onset and the maintenance of estrous cycles in some species, but this has not been investigated in swine. The mechanisms whereby adiposity and energy status influences reproduction are discussed. Human studies demonstrate a negative correlation between energy status, body fatness and plasma gonadotrophin levels. Also, adipose tissue has the ability to metabolize sex steroids, aromatizing androgens to estrogens and changing the direction of estrogen metabolism to produce more or less biologically potent estrogens.

Adipose Tissue↗
PubMed2006

Reproductive performance after transabdominal metroplasty: a review of 157 consecutive cases.

OBJECTIVE: To evaluate the impact of conventional transabdominal metroplasty on the reproductive outcome of symmetric uterine anomalies and to determine the complications of this procedure. STUDY DESIGN: A retrospective clinical analysis of 157 consecutive women who underwent surgery during a 25-year period. One hundred fifty-seven patients with a subseptate, septate or bicornuate uterus and history of recurrent abortions (124 cases) or infertility (33 cases) were included in this study. Operative technique was similar to the procedure first described by Bret and Guillet and by Tompkins. RESULTS: The fetal survival rate increased from 0.0% before surgery to 81.9% postoperatively in the recurrent abortion group and to 92.8% in the infertility group. Among women having undergone surgery, 63.8% gave birth to at least 1 healthy child, the proportion of previous habitually miscarrying and infertile women was 70.2% and 32.0%, respectively. No uterine rupture or any other complication was observed. CONCLUSION: Conventional transabdominal metroplasty seems to be a safe procedure in women with symmetric uterine anomalies and a history of recurrent miscarriages or otherwise unexplained primary infertility. No perioperative or subsequent peripartum complications were observed. Even in the era of operative hysteroscopy, transabdominal metroplasty remains the only approach in cases of bicornuate uterus.

Abortion, Habitual↗
PubMed1994

Weight, carcase composition and reproductive performance of pheasants (Phasianus colchicus) fed restricted or unrestricted diets.

Artificially reared hen pheasants, released in summer, are reported to have little reproductive success in the wild the following spring. One possible explanation is that such birds are unable to obtain an adequate diet after supplementary feeding ceases in February. When captive hen pheasants were fed an unrestricted diet they maintained constant muscle mass and fat reserves throughout the laying period. Hens restricted to pre-lay maintenance levels of nutrition after photostimulation initially laid good quality eggs at the same rate as the fully fed hens. However, by the time that they had laid the equivalent of one clutch of eggs, their energy reserves were approaching exhaustion, suggesting that they would have been incapable of incubating the eggs successfully. When fully fed hens were given wheat in place of a breeder diet, they quickly stopped laying but recovered equally quickly when fed a balanced ration again.

Animals↗
PubMed2001

Stability of dietary ascorbic acid and the effect of supplementation on reproductive performance of broiler breeder chickens.

1. The purpose of the study was to determine the stability of dietary ascorbic acid and the reproductive responses of broiler breeder chickens to supplemental 75 mg ascorbic acid/kg diet. 2. Six breeder flocks of 13,000 birds each were studied. Egg production, eggshell porosity, fertility, hatchability and plasma ascorbic acid were measured. 3. Storage of the diets under dry heat resulted in a linear decrease in ascorbic acid content and the rate of decline was 5-fold higher in the supplemented diet. 4. Differences were not detected between treatments in egg production, egg weight, eggshell porosity, fertility, hatchability or plasma ascorbic acid. 5. The results did not provide evidence of a beneficial reproductive response to the inclusion of ascorbic acid in commercial broiler breeder diets.

Animals↗
PubMedDate not supplied

Reproductive performance and three-dimensional ultrasound volume determination of polycystic ovaries following laparoscopic ovarian drilling.

OBJECTIVE: To evaluate the changes in ovarian volume and the reproductive outcome after laparoscopic treatment of polycystic ovaries (PCOS) in clomiphene-resistant anovulatory women. DESIGN: A prospective study of women undergoing laparoscopic treatment of polycystic ovaries. Ultrasound examination for three-dimensional (3D) volume determination was performed before and after surgery. SETTING: University teaching hospital. PATIENTS: Thirty-four women with polycystic ovarian syndrome who failed to ovulate with clomiphene citrate and who subsequently underwent laparoscopic ovarian drilling. INTERVENTIONS: Laparoscopic ovarian drilling and three-dimensional ultrasound examination. MAIN OUTCOME MEASURES: Cumulative probability of conception and changes in ovarian volume. RESULTS: Ovulation rate after the procedure was 30/34 (88.2%). Using Life Table Analysis, the cumulative probability of conception at 12 months follow-up was 70% (median, 8.1 months). The preoperative ovarian volume was 12.2 +/- 1.8 cm3 and 1 week after surgery it was 13.6 +/- 1.5 cm3. The ovarian volume 3 weeks after surgery, 6.9 +/- 1.3 cm3, was significantly smaller than that before surgery. CONCLUSIONS: Laparoscopic treatment of polycystic ovaries in women with clomiphene-resistant PCOS is associated with an ovulation rate of 88.2% and a cumulative pregnancy rate of 70% at 12 months. It appears also that laparoscopic ovarian drilling may result in a transient increase, with a subsequent significant reduction, in ovarian volume.

Adult↗
PubMed2005

Reproductive performance of pubertal red deer (Cervus elaphus) hinds: effects of genetic introgression of wapiti subspecies on pregnancy rates at 18 months of age.

Low reproductive productivity of young red deer (Cervus elaphus) hinds on New Zealand deer farms appears to reflect high incidences of puberty failure at 16 months of age. This is despite the general attainment of average liveweights 15-25 kg in excess of the accepted minimum threshold for puberty in subspecies of western European origin (scoticus, elaphus and hippelaphus) that form the basis of the national herd. The present study tests the hypotheses that introgression of the larger North American wapiti subspecies (nelsoni, manitobensis and roosevelti) into breeding herds (1) can be assessed from morphological features of individuals, (2) that there is a relationship between the level of wapiti parentage and non-pregnancy rate at 18 months of age (a proxy for puberty failure) and (3) that minimum liveweight thresholds for puberty increase with increasing levels of wapiti parentage. A total of 4329 18-month-old hinds across four "red" deer farms in southern New Zealand were scanned for pregnancy status. Each hind was assigned a wapiti score (WS) as a subjective assessment of the obviousness of wapiti features. Various body measurements were additionally recorded for each hind. A hair sample was collected for DNA analysis (14 markers) to objectively assign subspecies pedigree (i.e. "Elkmeter") on a subset of 1258 individuals. A total of 506 (11.7%) hinds were not pregnant at 18 months of age with rates varying between 4.1 and 37.3% between farms and years. Mean WS differed significantly between farms and reflected the genetic management policy of each farm. WS was positively correlated to Elkmeter for each farm/year (<0.05) although regression slopes varied significantly. WS was able to be adjusted for these differences to assign a corrected WS (CWS) for all 4329 individuals that estimated the proportion wapiti parentage. Discriminant analysis of morphological variables relative to Elkmeter supported the first hypothesis and showed that shoulder height and body length were good indicators of the degree of wapiti parentage within individuals. This enabled the development of an objective estimate of wapiti parentage (EWP). The actual level of such parentage within herds ranged from <5 to >55%. There was a significant negative association between wapiti parentage and pregnancy, which was strongly influenced by liveweight, supporting the second and third hypotheses. This was manifest as marked displacement of pregnancy probability curves in relation to liveweight between genotype groups, particularly for those groups with >20% wapiti parentage. For example, predicted threshold liveweights required to achieve a 90% pregnancy rate for EWP values that represent 0, 10, 20, 30, 40 and 50% wapiti parentage were 81, 81, 85, 106, 127 and approximately 137 kg, respectively. Within the study herds, the majority of hinds of 0-20% wapiti parentage exceeded the predicted 90% threshold liveweights for their genotype cohort. However, hinds with higher levels of wapiti parentage generally fell below the predicted threshold for their genotype group. The data strongly suggest that under liveweight performance levels measured for red deer, hinds with >20% wapiti parentage are at high risk of puberty failure.

Aging↗
PubMed1984

Acquired paternal influence in mice. Improved reproductive performance of CBA/H males immunized with rat blood cells.

Adult male CBA/H mice immunized against rat blood cells displayed a significant improvement in reproductive efficiency of 50% and 26% in two breeding programmes in relation to control male breeders exposed to phosphate-buffered saline (PBS). (Both types of male were mated to normal CBA/H females.) The improvement was reflected in the significant increase in successful mating frequency and size of litters produced. The unknown mechanism of this phenomenon is discussed in relation to the known reproductive consequences of conventional genetic crosses.

Animals↗
PubMed2006

Evaluation of corn furan fatty acid putative endocrine disruptors on reproductive performance in adult female chickens.

Based on evidence from rodent models, it was hypothesized that furan fatty acids found in corn would inhibit reproduction in the laying hen. An isomeric mixture of furan fatty acids [9, (12)-oxy-10,13-dihydroxystearic acid and 10, (13)-oxy-9,12-dihydroxystearic acid] was administered for a period of 3 wk via the diet (1 and 3 ppm) at levels greater than those in corn to 20-wk-old pullets. There were no overt indications of acute or chronic toxicity (no effects on mortality, feed intake, or average daily gain). Similarly, there was no dose-dependent effect on reproductive parameters [egg production, egg weight, shell thickness, ovarian weight, number or weight of large yolky preovulatory follicles, and number of small yellow follicles (4-8 mm in diameter)]. The present data do not suggest that furan fatty acids are a cause of concern to the poultry industry.

Animal Feed↗
PubMed1993

[The reproductive performance of sows with different malignant hyperthermia syndrome status].

Based on 200 litters descending from 50 sows relations between MHS-genotype and reproductivity were investigated. Breeds used were "Deutsches Edelschwein", German Landrace and a crossbred line. Evaluation of MHS-status was done by Polymerase Chain Reaction. Reproductivity traits were piglet numbers at different ages and litter growth. The sows were not preselected in regard to the halothane gene. MHS-negative sows showed increased reproductivity towards MHS-positives and within the negatives, the homozygote sows were superior to the heterozygotes.

Animals↗
PubMed1976

Reproductive performance and fertility testing in strain 13 and Hartley guinea pigs.

A study to test the effects of certain experimental manipulation on the reproductive capacity of male guinea pigs required verifying the fertility of the male guinea pigs before and after manipulation. Methods of testing fertility were evaluated, and normal reproductive data from preexperimental and control groups were tabulated and analyzed. No data from the actual experiments were included. Virgin and proven fertile males were mated with 1 (1:1) or 2 (2:1) virgin or proven fertile females. Inbred (13/N Umm) and conventional (Mfi:CFDH-ML (DH) ) guinea pigs were used. Ninety-five percent of both groups of males were fertile. Eighty-four percent of both groups of females were fertile. Male guinea pigs previously proven fertile had the same subsequent fertility rate as virgin males. Over one-third of the conceptions did not take place during the first estrus cycle (16 da) during which the males and females were mated. Strain 13 and Hartley females had litters of approximately the same size (3.1 vs 3.0), but the neonatal mortality was statistically lower (P less than 0.001) in the Hartley stock (9.3%) than in the Strain 13 guinea pigs (28.4%).

Animals↗