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Effects of acrylamide on rodent reproductive performance.

Acrylamide monomer causes peripheral neurotoxicity, mutagenicity, clastogenicity, male reproductive toxicity, prenatal lethality, and endocrine-related tumors in rodents. Acrylamide (and/or its metabolite glycidamide) binds to dopamine receptors and spermatid protamines and inhibits activity of kinesin and dyneine, resulting in interference with neuronal intracellular transport and sperm motility. Glycidamide binds to various proteins and DNA. Acrylamide at low doses decreases litter size, with rats more sensitive than mice. At higher doses, sperm morphology and motility and neurotoxicity are affected, which decreases mating frequency. Acrylamide does not affect female reproduction (females exhibit neurotoxicity). Dominant lethal mutations cause decreased newborn litter size. The mechanisms of action appear to be: (1) acrylamide/glycidamide binding to spermatid protamines, causing dominant lethality and effects on sperm morphology; and (2) acrylamide binding to motor proteins, causing distal axonopathy, including hindlimb weakness/paresis, and effects on mounting, sperm motility, and intromission. Glycidamide-induced mutations appear to play no role in reproductive or neurologic toxicity.

Acrylamide↗

Reproductive performance in rats with different histories of malnutrition.

1. Reproductive competence, as measured by weight gain during pregnancy, duration of pregnancy and foetal outcome, was assessed in primiparous rats (4--6 months of age) with various histories of malnutrition. 2. Although weight gain during pregnancy was reduced in rats with intergenerational malnutrition, the duration of pregnancy and number of live births did not differ from well-fed controls, suggesting adaptation of these measures to long-term dietary deprivation. 3. Rats malnourished from birth through pregnancy (one generation of malnutrition) had fewer live births than did rats with chronic, intergenerational malnutrition or well-fed controls rats. 4. Gestation was prolonged and weight gain accelerated among female rats with histories of intergenerational malnutrition, who had been provided with an adequate diet from birth through pregnancy.

Animals↗

Influence of protein-calorie malnutrition on reproductive performance of young and mature rats.

The effect on reproduction and fetal growth of a protein-deficient diet administration during pregnancy was studied in young and adult rats. Young (50-55 days old) and adult (90-100 days old) pregnant or nonpregnant rats were fed a normal diet (25% protein) or a protein-deficient diet (6% protein) during pregnancy or for a 22-day period (nonpregnant rats). All females were weighed during the experiment and body length measured in the young rats. After parturition, pups were counted, sexed and individually weighed. Litter size, number of stillbirths and presence of body lesions in the neonates were also recorded. Alimentary protein deficiency caused reduction in weight gain during pregnancy and in the postpartum period in young and adult rats. Pups from protein deficient dams weighed less at birth than the pups of control dams, although litter size was unaltered. Pups from young malnourished dams tended to weigh less than those from adult malnourished dams. The incidence of stillbirths was higher in malnourished rats, the highest values occurring in the adult group. These results suggest that alimentary protein deficiency during pregnancy in young rats reduces maternal weight gain, presumably reducing nutrient storage. This may cause fetal/maternal competition for nutrients leading to retardation of both maternal and fetal growth. Growth impairment may be an adaptive process, assuring fetal survival.

Aging↗

Effects of gonadotropin releasing hormone and prostaglandin F(2)alpha on the reproductive performance in postpartum cows.

A study was conducted to determine whether treatment with gonadotropin releasing hormone (GnRH) in combination with prostaglandin F(2)alpha (PGF(2)alpha) could enhance ovarian activity and uterine involution in postpartum dairy cows to reduce the calving interval. Cows were randomly assigned to one of three treatment groups. Cows (n = 8) in Group 1 received 100 mug GnRH intramuscularly (i.m.) twice on Day 20 and Day 35 postpartum, and 25 mg PGF(2)alpha i.m. on Day 47 postpartum. Group 2 (n = 8) received a single i.m. injection of 100 mug GnRH on Day 25 postpartum and 25 mg PGF(2)alpha i.m. on Day 37 postpartum. The Control Group (n = 9) did not receive hormonal treatment. Palpation per rectum of the reproductive organs and serum progesterone (P) determination were performed twice a week to monitor ovarian activity and uterine involution. Postpartum interval to the first ovulation was short in treated groups (Group 1, 21.0 d; Group 2, 26.3 d) compared with Control Group (30.1 d, P < 0.05). Likewise, mean frequency of ovulation was increased in both treated groups compared with the Control Group (P < 0.05). Cows in treated groups required fewer days to complete uterine involution than in the Control Group. The mean interval to the first service, the conception rate at first service and the number of services per conception showed no significant differences among the three groups, but the mean days from calving to conception were shorter for the treated groups (78.7 d in Group 1; 83.3 d in Group 2) than (109.1 d, P < 0.05) for the Control Group. Our results suggest that combined treatment with GnRH and PGF(2)alpha may enhance ovarian activity in the postpartum cow, resulting in improved reproductive performance.

Journal Article↗

The effect of porcine parvovirus and porcine reproductive and respiratory syndrome virus on porcine reproductive performance.

From a worldwide perspective, porcine parvovirus (PPV) and porcine reproductive and respiratory syndrome virus (PRRSV) are the most common viral causes of porcine reproductive failure. A typical epidemic of PPV-induced reproductive failure is presented as an increased number of mummified fetuses and sometimes, entire litters are mummified. If infection with PPV is very early in gestation, the number of liveborn pigs may be further reduced as a result of embryonic death and resorption. During the acute stage of infection gilts and sows have few, if any, clinical signs, and it is unlikely that PPV is ever the direct cause of abortion. In contrast, a typical epidemic of PRRSV-induced reproductive failure is presented as a broader spectrum of clinical features including abortions, late-term dead fetuses, stillborn pigs, and weakborn pigs. In the later stages of an epidemic, there may also be an increase in the number of mummified fetuses, but their prevalence is likely to be far less than during an epidemic of PPV-induced reproductive failure. During the acute stage of infection with PRRSV, gilts and sows may have few, if any, clinical signs, or they may be severely affected and even die. This difference largely reflects the relative virulence of the strain of PRRSV causing the epidemic. A timely and reliable laboratory diagnosis of either disease can be made when appropriate tests are performed with appropriate samples. Vaccines are available for prevention of both diseases.

Animals↗

Expert system for evaluation of reproductive performance and management.

A microcomputer expert system for dairy herd reproductive management was developed using an expert system shell and Turbo Pascal. The expert system initially examines the broad areas of days open, days to first breeding, detection of estrus, and conception rate to determine whether a problem exists. Interpretations ranging from "excellent" to "severe" were established for each trait. The system then selects an area for evaluation that has the largest negative influence on days open. Once an area has been selected for further evaluation, the expert system utilizes information from the user and DHI reports developed by the Dairy Records Processing Center in Raleigh, NC. These reports identify problems with conception categorized by production, parity, service number, days in milk, breed, and service sire. In addition, questions are presented by the expert system to isolate problems of accuracy of data, use of natural service, semen handling, AI technique, detection of estrus, signs of estrus, and other management areas. Recommendations and suggestions are given. Ten commercial herds having a conception rate less than 40% were evaluated by the expert system and by an extension reproduction specialist who supplied information for the system. Of 100 areas investigated, the expert system and extension specialist identified 47 as potential problem areas, agreeing on 85% of them. Most discrepancies resulted from the specialist applying a less restrictive standard when values were close to a preselected threshold.

Animal Husbandry↗

The reproductive performance of women before and after metroplasty.

Nineteen women with congenital uterine anomalies underwent metroplasty. Prior to surgical correction of the uterine malformation, 44 of their 45 (98%) pregnancies had ended with a spontaneous abortion, and no woman had a living child. Following metroplasty, only 4 of 18 (22%) pregnancies aborted, and 12 of the 14 (86%) women attempting pregnancy had a living child. There were no unusual intraoperative or postoperative complications. Metroplasty procedures can be performed safely, and are associated with excellent reproductive outcomes.

Abortion, Spontaneous↗

Toxicity of ebrotidine on reproduction. Toxicity on fertility and general reproductive performance, embryo-fetal toxicity and peri- and postnatal toxicity.

Reproduction toxicity studies of ebrotidine (N-[(E)-[[2-[[[2-[(diaminomethylene)amino]-4-thiazolyl]methyl] thio]ethyl]amino]methylene]-4-bromo-benzenesulfonamide, CAS 100981-43-9, FI-3542) are presented in this paper. Rats dosed with 50, 200 and 500 mg/kg p.o. of ebrotidine were used for the fertility and peri- and postnatal toxicity studies, and rabbits dosed with 25, 100 and 250 mg/kg and rats dosed with 50, 200 and 500 mg/kg of ebrotidine were used for the embryotoxicity study. The fertility study was designed in accordance with a 2-generation study protocol. The results showed that ebrotidine did not interfere with male and female gametogenesis, fertility, organogenesis, postnatal development and lactation in F0 or F1 animals. Only general or non-specific effects were attributed to treatment, such as a lower weight gain in parents or fetuses in rats, or a somewhat slower bone calcification in rats, which was shown to be recoverable and had no peri- or postnatal repercussions. Neither did the fertility study reveal a possible longer duration of gestation nor did the peri- and postnatal study show a lower weight of the F1 offspring. There was only an increase in rabbit embryonic mortality, probably related to some cases of abortion at the high dose. No potential antiandrogenic effect on the reproductive function has been found. Among the different doses used in both animal species, the maximum toxic effect-free dose was that of 25 mg/kg.

Abnormalities, Drug-Induced↗

Maintenance of a high level of reproductive performance in the beef cow herd.

To insure a high consistent reproductive program in a cow herd, 90 to 95 per cent of the cows must calve early each year and wean a heavy calf. To accomplish this, the producer should follow these steps: 1. Feed heifers to reach a target weight consistent with their breed. 2. Breed heifers 45 days to a bull known to sire small calves (Longhorn or Jersey or a proven bull within a breed). Also consider cows with Brahman blood to decrease birth weight. 3. Use a 60-day breeding season in the cow herd. 4. Have cows in good to moderate body condition at calving time. 5. Have cows gaining weight three weeks before breeding and during the breeding season. 6. Remove calves for 48 hours at the start of the breeding season. 7. Breed to fertile bulls.

Animal Husbandry↗

The influence of dietary salt level on water consumption, farrowing, and reproductive performance of lactating sows.

During two consecutive lactations using a switch-back design, 16 sows received a corn, cassava, barley, and soybean meal diet supplemented with either 8.5 or 1 g/kg of NaCl (.4% Na or .1% Na, respectively). The average daily water consumption during the 4-wk lactation period was greater (P < .01) for the sows fed the high-salt diet than for those fed the low-salt diet (13.9 vs 12.4 L, respectively). Urine production accounted for 27% of the water intake during lactation. This resulted in a difference during the entire lactation period of 42.2 L in water consumption (P = .07) and 11.4 L in urine production (P = .07). The Na and Cl concentrations of the urine for sows fed the high-salt diet were higher than for sows fed the low-salt diet (P < .05), but the K, Mg, P, and Ca concentrations were not influenced. The milk composition, measured at d 1, 13, and 27 of lactation, was relatively independent of the dietary salt level, except for the Cl concentration at d 1 after farrowing, which was higher (P < .05) for sows fed the high-salt diet. The moisture and ash content of the milk increased with the length of the lactation, irrespective of the diet. The increased ash content on d 13 and 27 of lactation was accounted for by the increased concentrations of P and Ca. There was no effect of dietary salt level on weight change of the sow or on the growth performance of the pigs. The interval from weaning to estrus (n = 13, t = 2.48, P = .029) was shorter for sows fed the high-salt diet than for sows fed the low-salt diet (6.2 +/- 1.0 and 12.6 +/- 3.1 d, respectively). More sows were unsuccessfully mated after receiving the low-salt diet during lactation. These results indicate that a low-salt diet for lactating sows results in lower water consumption, lower urine production, and lower Na and Cl concentrations in the urine. Milk composition, weight change of the sow, and growth performance of the pigs were not altered, but reproductive failures afterward may point to a salt deficiency during lactation.

Animals↗

Hormonal and metabolic adaptation to fasting: effects on the hypothalamic-pituitary-ovarian axis and reproductive performance of rabbit does.

To assess the impact of acute caloric shortage on reproduction, rabbit does were either fed ad libitum (control, AL), or fasted for 24 (STF) or 48 h (LTF) before induction of ovulation with GnRH injection. Blood samples were collected during the last 3 h of fasting, and the following 4 h after GnRH injection, when feed was provided again, to measure plasma concentrations of LH, estradiol-17beta, leptin, insulin, T3, corticosterone, glucose, and NEFA. Before re-feeding, plasma leptin, insulin, and T3 concentrations were lower (P < or = 0.01) in both fasted groups than in controls, but then gradually increased following realimentation to match those of controls. During fasting, corticosterone levels were higher (P < or = 0.01) in LTF than in STF and AL does, but decreased to control values soon after realimentation. During fasting, plasma glucose concentrations did not differ among groups, but upon re-feeding they markedly increased (P < or= 0.01) both in STF and LTF does. NEFA levels were also more elevated (P < or = 0.01) in fasted rabbits than in controls, and rapidly decreased (P < or = 0.01) after re-feeding. Following GnRH injection, LH peak was lower (P < or = 0.01) in LTF than in AL and STF does. Estradiol-17beta showed higher pulse frequency and amplitude in AL than in STF and LTF does. Compared to controls, receptivity rate of STF and LTF artificially inseminated does declined respectively by -20.5% (P < or = 0.05) and -22.7%, and fertility rate by -23.9% (P < or = 0.05) and 21.4%, but no difference was found in ovulation rate. In summary, nutritional status of does, as modified by fasting, greatly influenced fertility, metabolic and reproductive hormones.

Animals↗

Effects of hormonal treatments on reproductive performance and embryo production.

Developments in the use of drugs to improve reproduction and embryo production have focused on estrus and ovulation synchronization protocols and embryonic survival. Protocols for synchronization of ovulation eliminate the need for detection of estrus and allow timed insemination of all cows enrolled. Various estrogenic, progestational, GnRH and PGF2 alpha-like drugs are used to synchronize follicle development, CL regression and induction of ovulation. Strategies are discussed to optimize such programs to maximize herd pregnancy rates. Use of bovine Somatotrophin (bST) in combination with the Ovsynch protocol resulted in increased pregnancy rates, indicating possible effects on oocyte and embryonic development. Treatment of embryo donor cows with bST reduced the proportion of unfertilized oocytes and increased the number of transferable embryos. Furthermore, bST increased pregnancy rate when given to the recipient. Sub-luteal plasma progesterone concentrations after insemination have been associated with lower pregnancy rates. Injection of hCG on day 5 post-insemination resulted in induction of an accessory CL, increased plasma progesterone concentrations and increased conception rates. Strategies involving the use of sustained GnRH agonists to enhance CL development and alter follicular development are considered for future programs to enhance pregnancy rates.

Animals↗

Effects of vitamin A and beta-carotene on reproductive performance in gilts.

The effects of vitamin A and beta-carotene on various reproductive parameters were examined in 108 crossbred gilts. Gilts were fed a diet free of vitamin A and beta-carotene for 5 wk, then assigned to one of eight treatments. Statistical comparisons were performed on three sub-groupings of these treatments as follows: (1) DEFICIENT (received 2,100 IU of vitamin A X head-1 X d-1, (2) FED (received dietary supplementation of 0, 2,100 or 12,300 IU vitamin A and (or) 0, 32.6 or 65.2 mg beta-carotene X head-1 X d-1) or (3) INJECTED (received injection supplementation of 0 or 12,300 IU vitamin A and 32.6 mg beta-carotene X head-1 X d-1, administered once weekly). Gilts remained on treatment through weaning of litters at 21 d postpartum. Plasma vitamin A and beta-carotene levels were greatly elevated in INJECTED gilts. Concentrations of these compounds in plasma were similar between DEFICIENT and FED gilts. There was no treatment difference in number of corpora lutea/gilt. Embryonic mortality was lowest (P less than .01 to .02) in INJECTED gilts (14 +/- 3%) compared with DEFICIENT (29 +/- 5%) or FED (25 +/- 3%) gilts. Baby pig mortality averaged 6 +/- 1% and was not different among treatments. INJECTED gilts had more (P less than .05 to .01) piglets/litter at birth and at weaning (9.5 +/- .3 and 9.0 +/- .3 piglets/litter, respectively) than DEFICIENT (7.9 +/- .5 and 7.6 +/- .5 piglets/litter) or FED gilts (8.7 +/- .3 and 8.1 +/- .3 piglets/litter).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

Reproductive performance in population exposed to pesticides in cotton fields in India.

Data on reproductive histories were collected from 1016 couples in which the males were directly exposed to pesticides. For comparison data were collected from 1020 couples who were not exposed to pesticides and belong to the same socioeconomic group and age range. Statistical analysis revealed a significant decrease in fertile males and a significant increase in abortions among the wives of these exposed males when compared to the control group. The frequency of live births decreased significantly and still births, neonatal deaths, and congenital defects showed a significant increase in the offspring of exposed males when compared to the offspring of control group. Smokers exposed to pesticides showed a higher effect than nonsmokers exposed to pesticides. Eighty percent males in the exposed group showed ill health effects such as severe giddiness, nervous, skin, and eye disorders.

Abortion, Spontaneous↗

Impact of bovine viral diarrhea virus on reproductive performance in cattle.

The major economic impact of BVDV infections is in producing reproductive dysfunctions. The virus can have a detrimental impact on the developing fetus at all stages, but the most severe consequences occur early in gestation. The virus is maintained in the bovine population through the production of PI offspring. Only the NCB biotype of the virus can produce PI calves. The NCB biotypes is the one that produces the vast majority of BVDV infections and, as a consequence, the greatest economic losses. Biotype and antigenic variation are two independent variables and vaccines should emphasise antigenic composition, not biotype. A BVDV control program that does not emphasize heifers is doomed to failure.

Abortion, Veterinary↗

Factors affecting reproductive performance of dairy cows first inseminated after five weeks postpartum.

Various factors influencing reproduction of 307 Holstein cows were evaluated. Sources of variation of several measures were estrous certainty, time of day of detected estrus and insemination, method of thawing semen, ease of cervix penetration, presence of clear mucus at insemination, service number, service sire, inseminator, age of cow, maximum ambient temperature on the service date, and milk yield. Interval to first service of older cows was longer than of younger cows and shorter for cows with higher milk yield. Conception rate was higher for inseminations before noon than after noon and tended to be lower at inseminations when milk yield was at the extremes (low or high). Rate of conception was similar for cows whether inseminated at early or later postpartum intervals. More services were required by cows that were inseminated when milk yield was at the extremes (low or high). Fewer days open were associated with fewer total services and younger age at conception. Cows inseminated with semen thawed in hot (65 degrees C, 7 to 10 s) or warm (35 degrees C, 30 s) water conceived earlier postpartum than did those inseminated with semen thawed in the cow. Submitting cows for insemination after detection of standing estrus, mounting activity, or less certain symptoms of estrus had no adverse effect on fertility or days open.

Animals↗