SEARCH · PubMed Health

Results for “Reproductive performance”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 271 records · Page 15Linked to original sources

PubMed1994

Effects of dietary energy during gestation and lactation on reproductive performance of sows: a cooperative study. S-145 Committee on Nutritional Systems for Swine to Increase Reproductive Efficiency.

A cooperative experiment involving 999 litters was conducted at seven stations to assess the reproductive performance of gilts and sows fed different levels of energy during gestation and lactation (21 d) for three consecutive parities. Treatments consisted of two gestation (G) and two lactation (L) diets in a 2 x 2 factorial arrangement. Gestation treatments were diets fed to provide normal (5.9 Mcal/d, NG) or high (7.4 Mcal/d, HG) energy intake; lactation treatments were diets that contained 0 (NL) or 9% added fat (HL). Sows were provided ad libitum access to feed during the lactation period. Feeding the higher energy level during gestation increased pig birth weight (P < .01) and pig weight gain to weaning (P < .01). Sows that had been fed the higher level of energy during gestation (HG) ate less feed during lactation (P < .01) and lost more weight during lactation (P < .01). Increasing lactation energy intake by adding fat resulted in greater pig weight gains to 21 d of age (P < .01). Sows fed the HG-NL combination had fewer pigs on d 21 than all other treatment groups (G x L; P < .01). There was a G x L x parity interaction (P < .05) for days to estrus after weaning. Sows on the NG-HL or HG-NL treatments had increased days to estrus in Parity 1 (P < .05), whereas those on the NG-NL treatments had increased days to estrus in Parities 2 and 3 (P < .05). The HG-HL treatment minimized days to postweaning estrus during the three-parity study.(ABSTRACT TRUNCATED AT 250 WORDS)

Animal Feed↗

PubMed2005

Reproductive disorders of crossbred dairy cows in the central highlands of Ethiopia and their effect on reproductive performance.

The study was conducted to estimate the proportion of reproductive disorders and to determine factors affecting reproductive performance of crossbred dairy cows under four different production systems in the central highlands of Ethiopia. The principal postpartum reproductive disorders were retained fetal membranes (14.7%) and uterine infection (15.5%). Anoestrus was the major postpartum reproductive problem in the mixed crop-livestock production system (38.6%) and was significantly associated with this production system. Apart from anoestrus, the occurrence of reproductive disorders was not significantly associated with a production system. Most of the reproductive disorders occurred as a complex rather than as a single abnormality. Two or more abnormal conditions were seen in 11.4% of the cases. Each reproductive trait measured was affected adversely by reproductive disorders. Cows with reproductive disorders in each production system, lactation group and suckling and non-suckling group had longer intervals from calving to first service and to conception (p < 0.001) and required more services per conception (p < 0.001). Pregnancy rate and conception to first service were 84.7% and 51.7%, respectively, for cows without reproductive health problems; and 64.2%, and 15.1%, respectively, for cows with reproductive disorders (p < 0.001). Overall, intervals from calving to first service were shorter (p < 0.05) than in younger cows. Intervals from calving to first service and to conception were longer in suckling than in non-suckling cows (p > 0.05). Cows with a good body condition score (> 3.5) at calving had shorter calving to first service and conception intervals than cows in poor condition (p < 0.001). The results showed that reproductive abnormalities, coupled with poor body condition, are important factors that contributed to reproductive inefficiency. An appropriate reproductive health management, a reliable artificial insemination service and supplementary feeding could be the management options to reduce or alleviate some of the problems.

Anestrus↗

PubMed1980

Influence of supplemental dietary vitamin A on the reproductive performance of iodine-toxic rats.

Several indications of metabolic interactions between vitamin A and iodine prompted this experiment to determine if oral vitamin A supplementation would alleviate the effects of iodine toxicity using aspects of reproductive performance of rats as criteria. Sprague-Dawley female rats were acclimated to a purified diet and assigned, at breeding time, to 2 X 3 factorial experiments (n = 60) to test the effects of 600 and 12,000 IU vitamin A (experiment 1) and 12,000 and 480,000 IU vitamin A (experiment 2) as retinyl palmitate per kilogram diet, on the reproductive performance of rats fed 0.2, 500 and 1,000 ppm iodine. At these dietary levels of iodine, the daily iodine intake of the rats during gestatin in both experiments was 0.003, 8.8 and 17 mg, respectively, and was not affected by vitamin A intake. The iodine intakes correlated positively with the percentage of stillborn pups per litter, negatively with packed cell volumes of the whelping dams and negatively with the survival rates of their liveborn pups. Most pup deaths occurred within 24 hours postpartum and were attributed to the iodine-induced anemia and/or agalactia. Vitamin A supplementation did not significantly reduce the effects of iodine toxicity on the parameters measured, although there was a tendency for vitamin A to reduce the percent of stillbirths in litters of dams fed 1,000 ppm iodine, to increase the number of weaned pups per litter of dams fed 500 or 1,000 ppm iodine and to maintain relative liver size of the iodine-toxic dams during lactation.

Animals↗

PubMed1999

[Reproductive performance and milk production of Israeli-Holstein cows with different supplementation during the dry period].

In three field trials comprising 602 Israeli-Holstein dairy cows, the effect of the dry period ration on reproductive performance, culling rate and milk production was investigated. The cows were fed in groups. The basic dry period rations consisted for two herds of medium quality cereal hay and for one herd of corn straw, which were fed ad libitum. In each herd dry cows were assigned to an experimental and control group. Cows of the experimental group were supplemented with 1.5 to 3 kg of lactating cows mixed ration (LMR), whereas in the control group the amount of supplement was increased by the factor two or 3.3. In the experimental group the amount of the supplement was calculated to achieve levels of net energy and of crude protein close to NRC requirements; in the control group the level of net energy and protein was 12 to 18% higher as compared to the experimental group. The amount of LMR supplement in the experimental group of herds A, B, C were 1.5 kg, 1.9 kg, and 3 kg, respectively. In the control groups these amounts were 5 kg, 3.8 kg, and 6 kg, respectively. The groups fed moderate amounts of LMR supplement had a higher conception rate at first insemination, a higher percentage of cows conceiving and fewer cows culled in the consecutive lactation than cows fed increased amounts of LMR supplement. The lactational incidence of reproductive disorders and the milk production were not affected by the differences in feeding during the dry period. Reproductive performance and culling rate appeared to be more favorable for cows fed moderate amounts of supplement during the entire dry period or during the last 3 to 4 weeks of the dry period.

Animal Feed↗

PubMed1989

Effects of additional feed during late gestation on reproductive performance of sows: a cooperative study.

A cooperative research study involving 1,080 litters was conducted at eight stations to determine the effects of additional feed during the last 23 d of gestation on reproductive performance of sows and on preweaning performance of their pigs. Primiparous and multiparous sows were fed fortified corn- or sorghum-soybean meal diets (14% crude protein). Control sows received 1.82 kg/d from March through November and 2.27 kg/d from December through February. Treated sows were fed an additional 1.36 kg of feed/d from d 90 of gestation to farrowing. Sows were allowed to consume the same diet ad libitum during a 21-d lactation. Additional feed in late gestation resulted in greater (P less than .001) sow weight gain from d 90 to d 110 of gestation (16.8 vs 9.0 kg) and greater (P less than .001) parturition-lactation weight loss (21.3 vs 16.4 kg). Total weight gain from breeding to 21 d of lactation favored sows that received extra feed (27.5 vs 22.7 kg; P less than .001). Sows receiving extra feed had more live pigs at farrowing (10.05 vs 9.71, P = .06) and at 21 d postpartum (8.35 vs 8.06, P = .09), and the pigs were heavier at birth (1.48 vs 1.44 kg, P = .003) and at 21 d (5.37 vs 5.20 kg, P = .006). Lactation feed intake and number of days from weaning to estrus were not affected by treatment. The results indicate that additional feed in late gestation improves reproductive performance in sows. In this study, the cost of an additional 31 kg of feed/sow was more than offset by the value of the additional sow weight gain (approximately 5 kg), the additional .3 of a pig/litter at weaning and the additional 2.6 kg of total litter weaning weight.

Animal Feed↗

PubMed2005

A spreadsheet-based model demonstrating the nonuniform economic effects of varying reproductive performance in Ohio dairy herds.

A spreadsheet-based model was developed to estimate the economic effect of varying reproductive performance in dairy herds. Scenarios were created to model an average cow with respect to production, herd lifetime, and reproductive events. Average milk yield per day of life as well as lifetime calf and replacement heifer production were examined. Additional inputs representing milk, feed, semen, calf, and salvage prices were used to calculate net cash flow for each day of herd life for the average cow in a scenario. Economic comparison of different scenarios was accomplished using an equivalent annual cash flow (annuity) methodology.Herd performance measures and prices representative of Ohio dairy herds were used to establish a baseline average cow that had a 160-d calving-to-conception interval [days open (DO)]. Alternative scenarios that differed from baseline in DO, annual culling rate, and feed and milk prices were created to characterize the effects of changes. Under scenario inputs representative of typical Ohio dairy herds, the model indicated that a lower annual culling rate (25%) was preferable to higher annual culling rates (34 or 45%). The model estimated maximum average milk yield per day of life to occur at 110 DO. At 34% annual culling rate, calves and replacement heifers produced per lifetime declined as DO increased; beyond 150 DO, the modeled cow produced less than 1 replacement heifer per lifetime. The model also estimated a loss of $1.37 per cow per year for a 1-d increase in DO beyond 160 d. At 20% higher feed and milk prices, the model estimated a loss of $1.52 per cow per year; at 20% lower feed and milk prices, the model estimated a loss of $1.23 per cow per year. Furthermore, the model suggested that the loss associated with a 1-d increase in DO changed as DO changed. Using baseline inputs, the model calculated losses for a 1-d increase of $0.44 per cow per year at 130 DO and $1.71 per cow per year at 190 DO. The nonuniform nature of the cost of additional DO is important to veterinarians and producers. The implication is that inefficient reproduction becomes marginally more costly to producers as performance declines and warrants increased attention. Conversely, marginal benefits of improved reproduction decrease as performance improves. Herds with strong reproductive performance have less opportunity to capture economic benefits of improvement.

Animals↗

PubMed2005

Effect of kappa-casein and beta-lactoglobulin loci on milk production traits and reproductive performance of Holstein cows.

The effects of kappa-casein (kappa-CN) and beta-lactoglobulin (beta-LG) loci on milk production traits (milk, fat, protein, and lactose yield, fat, protein, and lactose content) and reproductive performance (gestation length, calving interval, age at first and second calving, number of services per conception) was estimated for 278 Holstein cows in the first 2 lactations. Genotypes of kappa-CN and beta-LG were determined by alkaline and acidic polyacrylamide gel electrophoresis. Milk production was recorded daily. Single-trait, mixed, linear models were used for the statistical analysis of the data. Results indicated that kappa-CN genotypes affected significantly protein yield and content (genotype AB > genotype AA). A tendency for increased milk and fat yield of animals having AB kappa-CN genotype was also found. Fat content and lactose yield and content were not affected. In the beta-LG system, significant differences were detected for milk yield (AB > AA), fat yield (BB and AB > AA), fat content (BB > AA and AB), and lactose yield (AB > AA). A tendency for higher protein yield was also observed (AB > AA). The beta-LG locus had no significant effect on protein and lactose content. No associations between polymorphisms at the kappa-CN locus and reproductive performance were found. There was a tendency, however, for cows with AB genotype to have older age at first and second calving. In the beta-LG system, cows with AA genotype had significantly shorter gestation length than did those with AB or BB genotype. No differences were detected between beta-LG polymorphisms for the other reproductive traits.

Animals↗

PubMed1995

Evaluation of the reproductive performance of women with elevated day 10 progesterone levels during ovarian reserve screening.

OBJECTIVES: To evaluate the relationship of elevated day 10 P levels (> or = 1.1 ng/mL, conversion factor to SI unit, 3.18) during ovarian reserve screening and reproductive performance. DESIGN: Prospective screening with longitudinal follow-up. INTERVENTIONS: One hundred seven women underwent ovarian reserve screening with a clomiphene citrate challenge test. MAIN OUTCOME MEASURES: Serum FSH, LH, and E2 levels were determined on cycle day 3 and FSH, LH, and P levels were determined on day 10. A fertility evaluation was completed and a treatment plan was instituted. RESULTS: Twenty-two of 107 (20.6%) women had day 10 P levels > or = 1.1 ng/mL. Women with elevated day 10 P levels were similar in age to women with normal day 10 P levels (< or = 0.9 ng/mL) but had significantly shorter menstrual cycles, higher day 3 and day 10 FSH levels, higher day 3 E2 levels, and higher day 10 LH levels than women with normal day 10 P levels. During ovarian hyperstimulation, women with elevated day 10 P levels required more ampules of hMG, had lower peak E2 levels, and had fewer mature follicles than women with a normal day 10 P level. Sixteen of 85 (18.8%) women with normal day 10 P levels became pregnant, but none of the 22 women with elevated day 10 P levels became pregnant. The incidence of diminished ovarian reserve was higher in women with elevated day 10 P levels (13/22; 59%) when compared with women with a normal day 10 P levels (9/85; 10.6%). CONCLUSIONS: Elevated day 10 P levels (> or = 1.1 ng/mL) during ovarian reserve screening is associated with diminished ovarian reserve and correlates with menstrual cycle parameters associated with a short follicular phase and poor reproductive performance.

Adult↗

PubMed1988

Potential for fecundin to influence the reproductive performance of merino ewes in Western Australia.

Four experiments were conducted at different locations in Western Australia to evaluate the effectiveness of immunizing young (maiden, 1 1/2 year old) and adult Merino ewes with Fecundin to improve their reproductive performances. The ovulation rates of immunized maiden ewes was increased (0.06-0.30) above that of untreated ewes in both experiments 1 and 2. However, there were no significant improvements in the marking percentages for the immunized ewes with the differences between the untreated and immunized ewes ranging from -16.4 to 5.8%. In comparison with untreated ewes immunization 6 and 2 weeks before the start of joining depressed ewe fertility by 26.1% whereas immunization 8 and 4 weeks before the start of joining did not significantly affect fertility. The availability of oat grain ad libitum prior to parturition and during early lactation did not improve the survival of lambs born to immunized ewes. In experiments 3 and 4 immunization of adult Merino ewes increased their ovulation rates (0.41-0.63) above untreated controls and tended to increase the proportion of pregnant ewes which had multiple pregnancies (from -2.3 to 34.2%). The responses at the end of lambing were variable (from -19.8 to 37.5% lambs marked) with high lamb mortalities occurring in some experiments. There was no adverse effect on the reproductive performances following consecutive annual immunizations over 3 years and the absence of treatment for 1 year did not prevent a response in the following year.

Aging↗

PubMed2000

Effect of gilt development diet on the reproductive performance of primiparous sows.

The objective of this study was to evaluate the effect of development diet on first-parity reproductive performance across different genetic types of females. Gilts (n = 708) 8 to 15 d of age from five genetic lines were assembled using a segregated early weaning protocol. Genetic types represented industry variation for reproductive capacity and lean growth potential. Sampling procedures were not designed to evaluate performance differences among the genetic lines. When the gilts weighed approximately 20 kg, they were moved from the nursery facilities to a slotted-floor, environmentally controlled facility, and seven to eight animals within a genetic type were penned together. When the gilts weighed approximately 40 kg, they were moved to a modified open-front facility. Nineteen gilts were allotted to each pen (.92 m2 per pig). Gilts were assigned to one of three development diets at 120 d of age. Diet 1 (high energy, 18% CP) and Diet 2 (high energy, 13% CP) were provided for ad libitum consumption to the assigned gilts until they weighed approximately 113 kg. Gilts receiving Diet 3 (23% CP) were fed 1.8 kg/d from 82 kg until they reached 180 d of age (approximately 100 kg). Gilts were fed 2 kg daily of a gestation diet from 180 d to 200 d of age and 2.7 kg daily from 200 d until mating. To stimulate the estrus cycle, gilts were commingled and exposed to vasectomized boars beginning at 180 d of age. Gilts that were in estrus and 210 d of age or older were artificially inseminated with commercial semen. Gilts not detected in estrus within the first 50 d of observation were injected with PG600 and estrus detection continued for 30 additional days. Of the 657 gilts entering breeding pens, 422 farrowed. Bred gilts were distributed to 10 cooperator facilities before farrowing. Mixed model procedures were used to analyze the data. Significant (P < .05) genetic type x gilt development diet interactions were found for number of pigs born, number of pigs born alive, total litter birth weight, and litter birth weight of pigs born alive. Significant interactions consistently involved one genetic line and gilt development Diets 1 and 2. Gilts from this genetic line-diet subclass had poorer farrowing performance (P < .05) than gilts from the same line fed development Diet 3. Only two other significant genetic line x gilt development diet interactions were found. Gilt development diet had little influence on first-parity reproductive performance.

Animal Feed↗

PubMedDate not supplied

Reproductive performance of dibromochloropropane-treated female rats.

Dibromochloropropane (DBCP) is an effective nematocide which has been shown to suppress spermatogenesis and cause infertility in both men and male rats. There are no similar reports concerning the effects of DBCP on female reproduction. The purpose of the present study was to attempt to interfere with the various phases of oogenesis. Proestral or pregnant rats were injected subcutaneously once with 40 mg/kg DBCP on one of each days of L12-L20 of gestation; a double dose (80 mg/kg) was injected in eight consecutive days (L11-L18). In addition, L13 fetuses were injected--directly into the amniotic sac--with 0.1 mg DBCP. Pooled data from the various days of gestation revealed that postimplantation losses were three times as high in the DBCP-treated animals as in DMSO-treated controls. Perinatal deaths were 58% higher and mean pup weights were 30% lower in the DBCP-treated rats than in controls. The reproductive performance of females exposed to DBCP while in utero was affected only to a limited degree (reduced number of ovulations and implantations) as compared with their DMSO counterparts. Doubling the dose (80 mg/kg) seriously reduced the birth weight of pups (50% of controls), all of which died within several hours post-partum. Direct injection of DBCP into embryos or to proestral rats did not have any adverse effects on their future reproductive performance. In contrast to the effect on spermatogenesis, it appears that oogenesis and ova are unaffected by DBCP.

Animals↗

PubMed2003

Effects of ammonium perchlorate on the reproductive performance and thyroid follicle histology of zebrafish.

Adult zebrafish were reared up to eight weeks in control water or in water containing ammonium perchlorate (AP) at measured perchlorate concentrations of 18 (environmentally relevant, high) and 677 ppm. Groups of eight females were paired with four males on a weekly basis to assess AP effects on spawned egg volume, an index of reproductive performance. All treatments were applied to four to five spawning replicates. At 677 ppm, spawn volume was reduced within one week and became negligible after four weeks. At 18 ppm, spawn volume was unaffected even after eight weeks. Also, perchlorate at 18 ppm did not affect percentage egg fertilization. Fish were collected at the end of the exposures (677 ppm, four weeks; control and 18 ppm, eight weeks) for whole-body perchlorate content and thyroid histopathological analysis. Fish perchlorate levels were about one-hundredth of those of treatment water levels, indicating that waterborne perchlorate does not accumulate in whole fish. At 677 ppm for four weeks, perchlorate caused thyroid follicle cell (nuclear) hypertrophy and angiogenesis, whereas at 18 ppm for eight weeks, its effects were more pronounced and included hypertrophy, angiogenesis, hyperplasia, and colloid depletion. In conclusion, an eight-week exposure of adult zebrafish to 18 ppm perchlorate (high environmentally relevant concentrations) affected the histological condition of their thyroid follicles but not their reproductive performance. The effect of 677 ppm perchlorate on reproduction may be due to extrathyroidal toxicity. Further research is needed to determine if AP at lower environmentally relevant concentrations also affects the thyroid follicles of zebrafish.

Animals↗

PubMed1980

Ovulation rate at first mating and reproductive performance of gilts.

Laparoscopy was used to estimate ovulation rate at first mating in 460 Large White/Landrace gilts. For 385 gilts which farrowed litter size was recorded and the relationships between age and mating, maternal litter size, ovulation rate and reproductive performance were examined. The mean ovulation rate of the gilts which farrowed was 10.9 +/- 0.14 corpora lutea and the mean first litter size was 8.0 +/- 0.12 piglets born with 7.5 greater than or equal to +/- 0.13 born alive. Ovulation rate was related to first litter size (r = 0.29, P < 0.001) but embryo loss was the major factor determining litter size, accounting for about 58% of the variation. None of the variable examined at the time of mating was sufficiently correlated with litter size to be useful as selection criteria for improving reproductive performance.

Animals↗

PubMed2004

The use of hormonal treatments to improve reproductive performance of anestrous beef cattle in tropical climates.

Most of the world's bovine herd is found in tropical regions. Bos indicus predominates, due to their adaptation to the climate and management conditions. Anestrous is the main factor that negatively affects reproductive performance of animals bred in these regions of the globe. Several factors affect postpartum anestrous, including suckling and maternal-offspring bond, and pre- and postpartum nutritional status. The short duration of estrus and the tendency to show estrus during the night, greatly affect the efficiency of artificial insemination (AI) programs in B. indicus cattle managed in tropical areas. Several restricted suckling or weaning procedures (temporary or permanent), and hormonal treatments have been used to induce ovulation and cyclicity in postpartum cows. Most hormonal treatments are based on progesterone/progestogen (P4) releasing devices associated with estradiol benzoate (EB), or a combination of GnRH/PGF(2alpha)/GnRH (Ovsynch). Treatments with GnRH/PGF(2alpha)/GnRH has presented inconsistent results, probably due to the variable number of cows in anestrous. Treatments using P4 devices and EB have resulted in apparently more consistent results than Ovsynch programs in B. indicus cattle; however, pregnancy rates are low in herds presenting high anestrous rates and moderate to low body condition. The addition of an eCG treatment at the time of device removal, which increased plasma progesterone concentrations and pregnancy rates in anestrous postpartum suckled B. indicus cows, may be useful to improve reproductive performance of beef cattle in tropical climates.

Anestrus↗

PubMed1981

Effects of dietary fat on feed efficiency, reproductive performance, and in vitro lipogenesis by the turkey hen.

Two 16-week feeding trials were conducted with Large White turkey hens to determine the effect of graded energy levels (as fat-6, 18, 30, and 42% substituted isocalorically for corn meal) on energy efficiency, reproductive performance, lipogenic enzyme activity, and in vitro lipogenesis. A constant calorie: gram-protein ratio (17:1) was maintained for all dietary treatments. Also, other components of the diets were adjusted to maintain constant energy-to-nutrient ratios. Additional fat increased (P less than .05) energy utilization but had no effect on reproductive performance. Additional fat calories decreased (P less than .05) malic enzyme, isocitrate dehydrogenase, and fatty acid synthetase activities; however, fatty acid synthetase activity was the most responsive of the three enzymes to 42% metabolizable energy as fat. Liver lipid content was also decreased (P less than .05) by additional fat calories. In vitro lipogenesis (fatty synthesis from 10 mM (1-14C) sodium acetate) was also decreased (P less than .01) by additional dietary fat.

Animal Feed↗

PubMed1992

A preliminary study of growth, serum prolactin and reproductive performance of beef heifers grazing Acremonium coenophialum -infected tall fescue.

In an experiment with a 2x2 factorial arrangement of treatments, 32 virgin Angus heifers were used to study effects of tall fescue endophyte Acremonium coenophialum and energy supplementation on reproductive performance. Treatments were feeding of endophyte-free (EF) or endophyte-infected (EI) tall fescue without (0%) and with energy supplementation at one percent group mean body weight (1%). Blood samples were collected at 28-day intervals for prolactin (PRL). Starting 21 days before the breeding season, blood was also collected weekly for progesterone (P(4)) and PRL. After 99 days of grazing, heifers received Syncro-Mate-B (SMB) and were then artificially inseminated over a 30-day period. Heifers on EI-0% had a lower (P<0.05) average final body weight. Highest average daily gain was observed in heifers fed EF-1% (0.98 kg/day), whereas, heifers fed EI-0% had lowest average daily gain (0.53 kg/day; P<0.05). Endophyte-infected fescue depressed serum PRL concentrations (171 and 143 ng/ml vs 70 and 85 ng/ml; EF-0% and EF-1% vs EI-0% and EI-1%, respectively; P<0.05). No differences were observed among treatments in luteal activity before or after SMB, in pregnancy rates after a synchronized estrus or in overall pregnancy rates during the 30-day breeding season. Endophyte-infected fescue decreased average daily gain and depressed serum concentrations of prolactin, but had no effect on reproductive performance as measured in this study.

Journal Article↗

PubMed1983

Effects of long-term consumption of sewage solids on reproductive performance and serum progesterone and estradiol-17beta in mature fine-wool ewes.

Eighty-four mature fine-wool ewes were randomly allotted to one of three dietary treatments to examine the influence of dietary sewage solids on reproductive performance. Treatments were a basal diet or basal plus either 3.5% cottonseed meal (CSM) or 7% sewage solids. Serum progesterone and estradiol-17beta measured in blood samples collected through an estrous cycle just before the breeding season of the first and second years were not adversely influenced by sewage feeding. Progesterone concentrations quantified in weekly blood samples collected during gestation and lactation of both years did not differ (P>0.10) among treatments. During the first lambing season, lambing data showed that ewes consuming CSM produced slightly more lambs per ewe exposed (P<0.10) than either basal- or sewage-fed ewes. During the second breeding season, midventral laparotomies revealed that ovaries from ewes receiving CSM contained more (P<0.10) corpora lutea than did those from either basal- or sewage-fed animals. However, at the end of the second lambing season, no differences (P>0.10) among treatments in the number of lambs born or weaned were observed. A third year's lambing data also revealed no difference (P>0.10) among treatments for lambing rates. These data indicate that prolonged consumption of a diet containing 7% sewage solids has little, if any, detrimental effect on reproductive performance of mature fine-wool ewes.

Journal Article↗

PubMed1988

Effect of sex ratio of the birth litter on subsequent reproductive performance of gilts.

Records on age at puberty from 1,555 gilts and total number of pigs born in litters of 1,187 gilts from the Nebraska gene pool population were used to evaluate the effects of uterine environment on subsequent reproductive performance. Independent variables were line, year, line x year, proportion of males in the birth litter (sex ratio), number born in the birth litter (fraternity size) and sex ratio x fraternity size. Sex ratio, fraternity size and their interaction influenced age at puberty (P less than .01) but not number born (P greater than .2). Partial regression coefficients indicated that age at puberty tended to decrease as sex ratio increased, particularly in small litters. Although the regression coefficients were relatively large, sex ratio, fraternity size and their interaction accounted for only 1.3% of the variation in age at puberty within line x year subclass. These results offer little encouragement for the use of sex ratio as a phenotypic selection criterion for improvement of reproductive performance in gilts. Results suggest that female swine are similar to rodents in response to uterine environmental effects.

Animals↗