Reproductive Performance Of Offspring Research Articles

Developmental programming of production and reproduction in dairy cows: II. Association of gestational stage of maternal exposure to heat stress with offspring's birth weight, milk yield, reproductive performance and AMH concentration during the first lactation period

Although the negative effect of maternal exposure to heat stress on production and reproduction of offspring has been reported, there are some discrepancies among various studies about which gestational stage is more critical in this regard. Therefore, the present research was conducted to identify during which stage(s) of pregnancy maternal exposure to heat stress would lead to more dramatic decrease in productive and reproductive performance of offspring. To this end, offspring were classified based on the gestational stage they were in utero exposed to heat stress into four categories, including heat stress exposure (HSE) during only the first trimester of gestation (HSE1), HSE during the first and second trimester of gestation (HSE2), HSE during the second and third trimester of gestation (HSE3) and HSE during only the third trimester of gestation (HSE4). In study I, data of birth weight, milk yield and reproductive variables of 11,788 offspring and data of the month they were conceived were retrieved. In study II, blood samples (n = 521) were collected from offspring in various categories of HSE for measurement of serum AMH. Offspring in HSE1 and HSE2 categories were heavier than offspring in HSE3 and HSE4 categories (P < 0.0001). Offspring in HSE1 and HSE3 categories had the lowest and highest milk production, respectively (P < 0.05). First service conception rate was the greatest and worst in HSE1 and HSE4 categories, respectively (P < 0.05). Service per conception and calving to conception interval were greater in HSE2 than HSE4 category (P < 0.05). Concentration of AMH was lower in HSE1 than HSE4 category (P < 0.05). In conclusion, the present study indicated that the early stage of gestation could be a more critical period for the negative impact of in utero heat stress on developmental programming of milk production and ovarian reserves. Yet an evident temporal pattern for the adverse effect of maternal heat stress on developmental programming of reproductive performance in offspring was not found.

Developmental programming of production and reproduction in dairy cows: I. Association of maternal parity with offspring's birth weight, milk yield, reproductive performance and AMH concentration during the first lactation period

Multiparous dams have been reported to produce offspring with greater fertility and higher AMH concentration, as a marker of ovarian reserves, as compared with nulliparous and primiparous dams. Yet it has remained to be addressed whether this phenomenon can still be true for old multiparous cows which might experience some geriatric changes in their reproductive system. Therefore, the present study was conducted to evaluate the productive and reproductive performance of offspring with different maternal parity. To this end, offspring were classified based on their maternal parities into four categories, including offspring of nulliparous (no previous parity), primiparous (one previous parity), young multiparous (two to six previous parities) and old multiparous (seven or more previous parities) dams. In study I, data of birth weight, milk yield and reproductive variables of 11,788 offspring and data of their maternal parity were retrieved. In study II, blood samples (n = 521) were collected from offspring with various maternal parity for measurement of serum AMH. Birth weight was the lowest in the offspring of nulliparous dams (P < 0.0001) and it was lower in offspring of primiparous and old multiparous dams than offspring of young multiparous dams (P < 0.05). Milk production was the lowest in offspring of old multiparous dams (P < 0.01), and it was lower in offspring of young multiparous dams than offspring of nulliparous and primiparous dams (P < 0.0001). Offspring of old multiparous dams had greater first service conception rate, less services per conception and shorter calving to conception interval than offspring of nulliparous, primiparous and young multiparous dams (P < 0.05). Furthermore, AMH concentration was higher in offspring of old multiparous dams than offspring of nulliparous and primiparous dams (P < 0.05). In conclusion, the present study revealed greater milk production in offspring resulting from dams with lower parity, probably due to the genetic selection for improvement of milk production in dairy cows which imparts the younger generations greater genetic merits for milk production. Reproductive performance, however, was greater in offspring born to dams with higher parity, particularly those born to old multiparous dams, and this phenomenon might be related to their lower milk production and higher AMH concentration.

Maternal exposure to fenarimol promotes reproductive performance in mouse offspring

Although fenarimol is a widely used chlorinated fungicide applied to fruits and vegetables and is a suspected endocrine disrupter, transgenerational studies of low doses of fenarimol exposure are not currently available. The aims of this study are to address the effect of maternal exposure to low doses of fenarimol on the reproductive performance of offspring and to investigate the expression changes of genes associated with this effect. Pregnant mice were orally exposed to low doses (0, 2, 20, and 200 μg/kg body weight) of fenarimol during gestational and lactational periods, and their offspring were assessed. The body and organ weights and anogenital distance (AGD) of mice offspring (F1) maternally exposed to fenarimol were determined, and the reproductive performances of these mice were assessed by mating and ovarian follicular and sperm analyses. Fenarimol-exposed F1 mice had shortened AGDs, increased body weight with altered organ weights, increased number of pups, increased number of ovarian follicles, and enhanced sperm quality. Microarray data showed 82 upregulated and 743 downregulated genes in the ovaries of fenarimol-exposed mice, in which Cyp17a1, Cyp19a1, and ERβ were upregulated. In addition, Nobox, a pivotal gene required for proper folliculogenesis, was significantly increased in the ovaries of F1 mice. In conclusion, maternal exposure to fenarimol promotes normal reproductive function in female mouse offspring by increasing the expression levels of genes crucial for ovarian folliculogenesis, identifying fenarimol as a chemical that stimulates reproductive performance. Thus, consumption of fenarimol-contaminated diets by mothers may possibly alter normal reproductive function of offspring in humans and wildlife.

Effects of in utero through lactational exposure to dicyclohexyl phthalate and p,p′-DDE in Sprague–Dawley rats

Anti-androgenic chemicals alter sexual differentiation by a variety of mechanisms, and the mechanisms between phthalate esters and p,p'-DDE are considered to be different. We performed an in utero through lactational exposure assay using dicyclohexyl phthalate and p,p'-DDE to investigate the sexual differentiation of these chemicals. Pregnant CD (SD) IGS rats were given dicyclohexyl phthalate or p,p'-DDE orally from gestational day (GD) 6 to postnatal day (PND) 20, and the endocrine-mediated effects in dams and their offspring were examined. The reproductive performance of offspring was also examined. The doses of dicyclohexyl phthalate were 0, 20, 100, and 500 mg/kg/day, and those of p,p'-DDE were 5, 15, and 50mg/kg/day. Using the dicyclohexyl phthalate, a dam in the 500 mg/kg group showed dystocia and died. The viability index of offspring on PND 4 decreased in the 500 mg/kg group. Prolonged preputial separation, reduced ano-genital distance, increased areolas/nipple retention, hypospadia, decreased ventral prostate and levator ani/bulbocavernosus muscle weights and decreased testicular germ cells were observed in male offspring in the 500 mg/kg group. In the assay using p,p'-DDE, decreased viability index of offspring on PND 21, prolonged preputial separation in male offspring and early vaginal opening in female offspring were observed in the 50mg/kg group. The copulation and fertility indices decreased in the reproductive performance of offspring in the 50mg/kg group. The endocrine-mediated effects were detected in offspring of dams given 100mg/kg dicyclohexyl phthalate, and in offspring of dams given 20mg/kg p,p'-DDE. Our results suggest that the in utero through lactational exposure assay is a useful method to detect endocrine-mediated effects and that further comparative study between this assay and two-generation reproductive test are necessary when this assay becomes one of the definitive tests.

Lack of adverse effects in pregnant/lactating female rats and their offspring following pre- and postnatal exposure to ELF magnetic fields.

We have recently reported that exposure of pregnant rats to 60 Hz at field strengths up to 0.5 mT during the entire period of pregnancy did not induce any biologically significant effects on both pregnant dams and embryo-fetal development. The present study was carried out to investigate the potential effects of gestational and lactational MF exposure on pregnancy, delivery, and lactation of dams and growth, behavior, and mating performance of their offspring in rats. Timed-pregnant female Sprague-Dawley (SD) rats (24/group) received continuous exposure to 60 Hz magnetic field (MF) at field strengths of 0 (sham control), 5 microT, 83.3 microT, or 0.5 mT. Dams received MF or sham exposures for 21 h/day from gestational day 6 through lactational day 21. Experimentally generated MF was monitored continuously throughout the study. No exposure-related changes in clinical signs, body weight, food consumption, pregnancy length, and necropsy findings were observed in dams. Parameters of growth, behavior, and reproductive performance of offspring showed no changes related to MF exposure. There were no adverse effects on embryo-fetal development of F2 offspring from dams exposed to MF. In conclusion, exposure of pregnant SD rats to 60 Hz at field strengths up to 0.5 mT from gestational day 6 to lactational day 21 did not produce biologically significant effects in dams, F1 offspring, or F2 fetuses.

REPROUCTIVE AND DEVELOPMENTAL TOXICITY STUDY OF MOFEZOLAC (N-22) (2) : Study by Oral Administration of N-22 during the Period of Fetal Organogenesis in Rats

The teratogenicity of mofezolac (N-22), a new developed analgesic and anti-inflammatory agent, was investigated in rats. N-22 was given orally to pregnant rats of the Jcl: Wistar strain (30 rats per group) at dose levels of 10, 50, 100 and 150 mg/kg/day from days 7 to 17 of gestation. Caesarean sections were performed on 20 dams per group on day 20 of gestation and their fetuses were examined for external, visceral and skeletal abnormalities. The remaining 10 dams per group were allowed to deliver and their offspring were examined for growth and reproductive performance. Results were as follows. 1. Effects on F0 generation At 150 mg/kg, eleven out of the 30 dams exhibited decreased motor activity, pale eyes, unkempt fur, urine-smeared lower abdomen, weakness and emaciation. At autopsy, twelve dams revealed gastrointestinal ulcers, peritonitic lesions, hypertrophy of the spleen, adrenal and mesenteric lymph node, atrophy of the submaxillary gland, thymus and liver and discoloration of the liver and kidney. Death, sacrificing in extremis, premature or delayed delivery and poor nursing occurred in one to two dams each. Food consumption was significantly decreased and body weight gain was significantly retarded in this dose level group. At 100 mg/kg, urine-smeared lower abdomen, hypertrophy of the spleen and poor nursing were observed in one dam each. 2. Effects on F1 generation At 150 mg/kg, significantly decreased fetal weight, increased number of immature fetuses and significantly retarded ossification of the 5th and 6th sternebrae and coccygeal vertebrae as well as significantly depressed body weight gain of female offspring were observed. No abnormalities were observed in each treated group in terms of development, behavior, learning ability and reproductive performance of offspring. 3. Effects on F2 generation No abnormalities were observed in fetuses and newborn young in each treated group. Based on these results, the maximum non-effective doses of N-22 in this study were considered to be 50 mg/kg/day for dams and offspring and 100 mg/kg/day for fetuses.

Reproductive performance of offspring from mares administered altrenogest during gestation

Thirty light-horses, two-year-olds (15 fillies, 15 colts) were evaluated for reproductive performance. The dams of these offspring had been administered either: 1) 2 ml of neobee oil per 44.5 kg body weight (controls)); or 2) 2 ml of altrenogest (2.2 mg/ml) orally per 44.5 kg body weight.. Treatments were administered daily from day 20 to 320. Interval to first ovulation with estrus and duration of estrus, diestrus and estrous cycle were similar (P>0.05) for treated and control fillies. In addition, pregnancy rate per cycle and after 3 cycles was not different (P>0.05) between groups. Age at puberty was similar (P>0.05) for treated and control stallions. In addition seminal characteristics of the last 9 ejaculates prior to castration as well as sexual behavior were not different (P>0.05) between groups. Testicular weight and size and spermatozoal production was not affected by treatment. Thus, treatment of mares with altrenogest during gestation had no affect on reproductive performance of either female or male offspring.

Reproductive Performance from Daughters of Single and Multiple Trait Selected Sires

Sires selected for milk in first lactation (Yield) and those selected for udder conformation, percentage of daughters culled in first lactation, and fat-corrected milk (Merit) were mated randomly to cows in the Beltsville herd. Subsequent offspring were mated to bulls from the same selection group as their sires. Reproductive traits were numbers of heats and services, age at first heat, gestation length, and age at first calving for heifers and numbers of heats and services, gestation length, days to first heat postpartum, and calving interval for cows. Selection groups differed only for gestation length with Merit females having a 2 day longer gestation than Yield females. Yield females calved earlier (12 days) and had shorter calving intervals (14 days) than Merit females.Mating bull was significant for gestation length and for percent pregnant on a given service but not on first or first four services. Selection groups differed in gestation length only. Variance components for mating bulls for all traits and for sire of cow for gestation length were all less than 10% with most less than 3%.Reproductive performance of offspring from selection of bulls solely for milk in first lactation was not inferior to that of offspring of bulls selected less intensely for milk.

Reproduction study of carteolol hydrochloride in mice. Part 2. Peri -and postnatal toxicity.

Carteolol was orally administered to mice once a day at doses of 3, 30 and 150 mg/kg/day during the perinatal and lactation periods and evaluated on its adverse effects on pregnant animals and their offspring. No appreciably abnormal findings related to the drug administration were revealed. Therefore, it was concluded that carteolol have no serious toxic potential on parturition and lactation by mother animals, no adverse effects on growth and development, and behavioral and reproductive performance of offspring and no carcinogenic action through placental and milk transfer.