Reproductive Performance Of Gilts Research Articles

Measurement and characterization of swine uterine estradiol receptors: the effects of puberty induction on estradiol receptors and corpus luteum function.

Two types of cytoplasmic 17 beta-estradiol (E2) binding activity were identified and characterized in the uteri of pregnant, cycling and prepubertal, cycle-induced (400 IU pregnant mare's serum gonadotrophin (PMS) + 200 IU human chorionic gonadotrophin (hCG)) gilts. Overall, type I affinity and capacity were Kd 1.94 +/- 0.51 nM and 5.410 +/- 1.09 pmol/mg protein, respectively; type II apparent dissociation constant and capacity were Kd 21.34 +/- 6.83 nM and 62.58 +/- 15.96 pmol/mg protein, respectively. Cytoplasmic luteal E2 receptors were undetectable in all groups. Uterine E2 receptor activity was eluted from diethylaminoethyl columns by a 0.05-0.15 M KCl gradient. Sodium dodecyl sulfate polyacrylamide gel electrophoresis indicated a molecular weight of 70 400-79 000. Excluding gilts with cystic ovarian follicles (16.67%), prepubertal gilts treated with PMS + hCG versus cycling sows had lower serum progesterone on days 6 and 9-13 of the estrous cycle and lower 13,14-dihydro-15-keto prostaglandin F2 alpha levels on days 0-9 and 13-17 of the cycle. Implants, containing 200 mg estrone inserted subcutaneously on days 12-19 after PMS + hCG treatment in gilts, had no discernible effects on these parameters. These results indicate that the diminished reproductive capacity of the gilt, in which cycle activity is induced by PMS + hCG, is likely due to decreased luteal progesterone secretion. Preliminary data also suggest that the lack of E2 receptors may contribute to the low reproductive performance in gilts with cystic ovarian follicles.

Reproductive performance of gilts induced into puberty with oestradiol benzoate or a combination of pregnant mare's serum gonadotropin and human chorionic gonadotropin

ABSTRACTThe efficacy of a single injection of oestradiol benzoate, or a combination of pregnant mare's serum gonadotropin (PMSG) and human chorionic gonadotropin (HCG), for the induction of a fertile oestrus and ovulation in the prepubertal pig was investigated in two experiments.In the first experiment, 1·2 mg of oestradiol benzoate induced 21/23 gilts to ovulate, and 22/23 gilts showed oestrus and were inseminated on day 4 or 5 after treatment. At 28 days after insemination, 12 gilts were pregnant and carrying a mean of 7·1 (s.d. 3·3) live embryos, giving an embryonic survival rate of 0·703. All the 22 gilts treated with 400 international units PMSG plus 200 international units HCG as a single injection ovulated but only 10 showed oestrus and were inseminated. At 28 days after insemination, six gilts were pregnant with a mean of 13·0 (s.d. 5·8) live embryos, giving an embryonic survival rate of 0·583.In the second experiment, 9/11 oestradiol benzoate and 10/10 PMSG/HCG gilts ovulated in response to treatment. Oestrous detection and insemination were delayed until the expected time of the second oestrus, 20 to 30 days after treatment. Nine gilts (3 oestradiol benzoate, 6 PMSG/HCG) showed oestrus in this period and eight were inseminated. Five gilts were pregnant 28 days after insemination with a mean of 11·4 (s.d. 1·1) live embryos, giving an embryonic survival rate of 0·860.

Amino acid supplementation of low-protein diets for swine: effects of gestation treatment on reproductive performance of gilts and sows.

The effect of lysine and tryptophan addition to an all-corn diet fortified with vitamins and minerals fed to gestating gilts and sows was studied in a series of five trials. The experiments were designed to establish the effect of the addition of the two amino acids on: 1) N balance, 2) reproductive performance over two consecutive parities and 3) the immune response of the gestating gilt and transfer of immune proteins to the nursing pig. Nitrogen retention by gravid gilts fed an all-corn gestation diet increased (P less than .05) in response to lysine addition, but was not affected by subsequent addition of tryptophan. Daily N retention of gravid gilts fed the corn or corn and amino acid-supplemented diets was lower than that of gilts fed a 12% crude protein (CP) diet. Reproductive performance for two parities, as evaluated by gestation and lactation weight gain and, number and weight of pigs at birth and at 28 d was similar among treatments. Evaluation of the amino acid status of gestating gilts by measurement of the development of specific antibody response to sheep red blood cells and bovine serum albumin showed a trend for improved antibody development in gilts fed corn diets supplemented with both lysine and tryptophan and in the passive immunity of their offspring. Total whey protein and globulin content of 0-h colostrum was not affected by dietary treatment. The lack of a depression in reproductive performance of gilts fed an all-corn diet could be because of compensatory N retention. During the 4 to 5 d before parturition, all gilts were fed the 12% protein control diet. Gilts that were fed a corn diet from d 1 to 108 of gestation retained 40% more (P less than .01) N from d 109 to 114 of gestation than gilts that had been fed the 12% protein diet throughout gestation.

CHOLINE SUPPLEMENTATION OF BARLEY-WHEAT-SOYA DIETS AND THE REPRODUCTIVE PERFORMANCE OF SWINE

The effect of choline supplementation (434 mg/kg of diet) on reproductive performance and incidence of spraddle leg condition in baby pigs was studied in two experiments, using 128 gilts (64 Lacombe + 64 Yorkshire) in exp. 1 and 64 primiparous sows and 64 gilts, half from each breed, in exp. 2. In exp. 1 (winter) supplemental choline significantly (P < 0.05) increased the number of live pigs born (9.64 ± 0.41 vs. 7.90 ± 0.31) and weaned (7.50 ± 0.68 vs. 6.73 ± 0.25) for Lacombe, but not for Yorkshire (8.40 ± 0.56 vs. 9.00 ± 0.45 and 7.40 ± 0.33 vs. 8.10 ± 0.33, respectively) gilts. The mean birth weights and weight gains to 3 and 5 wk of age were similar for the control and choline-supplemented groups. In exp. 2 (summer) choline supplementation had very little effect on reproductive performance of gilts or sows from either breed. The incidence of spraddle leg condition was very low in both experiments and was not influenced by choline supplementation. These results indicate that the choline content of barley-wheat-soya diets was adequate for reproduction in Yorkshire gilts and sows, but Lacombe gilts may require supplemental choline during winter for optimum reproductive performance.

Reproductive performance of gilts bred on first versus third estrus.

Reproductive performance of gilts initially bred on first observed estrus was compared with that of gilts bred on third observed estrus. One-hundred and twelve Yorkshire gilts were used and 106 conceived. Conception rate to initial breeding was lower among gilts bred on first versus third observed estrus (69.6 vs 77.4%). Estrus was observed in some gilts between 140 and 149 days of age; the mean age at estrus for all gilts that were bred was 177.8 days. The mean weight at puberty was 91.7 kilograms. There was a tendency toward increased litter size at birth and weaning when breeding was delayed to third estrus, but the difference was not statistically significant. Live weight of piglets was increased in litters from sows bred initially on third estrus. The weaning-to-estrus or conception interval was not influenced by initial breeding on first or third estrus. Maintaining gilts until third observed estrus required feed and accommodation for approximately 44 additional days before breeding and resulted in 1.4 additional pigs per sow over three parities.

Induction of puberty in gilts 1. The effects of rearing conditions on reproductive performance and response to mature boars after early puberty

ABSTRACTAttainment of puberty and the ovulation rates for the first three oestrous cycles were studied in gilts reared to 160 days alongside contemporary castrate or entire males before introducing them to mature boars.Gilts which were introduced to the boars at 160 days of age reached puberty at younger ages and lighter weights than isolated gilts. Rearing treatment did not affect the age of puberty. Gilts which were isolated from boars after 160 days of age reached puberty earlier if they had been reared with entire rather than castrate contemporary males. The interval from introduction of the boars to first oestrus was related to age and weight at the time of introduction.Ovulation rate at the pubertal oestrus was the same in both isolated groups, and higher in both these groups than for gilts induced into early puberty by boars. Ovulation rate increased at the second and third oestrous cycle and groups differed only at the first oestrus. In a second experiment, the reproductive performance of gilts approximately 218 days of age experiencing either their first, second or third oestrus was studied. No differences were found among the groups and the conclusion is that in gilts of similar age and weight the oestrous cycle at which mating takes place does not affect reproductive performance.

Effect of dietary protein during growth and gestation on development and reproductive performance of gilts.

Effect of dietary protein during growth and gestation on development and reproductive performance of gilts.

Effect of Protein Level on Growth, Nitrogen Balance and Reproductive Performance in Gilts

Effect of Protein Level on Growth, Nitrogen Balance and Reproductive Performance in Gilts

Effect of dietary energy in gestation on reproductive performance of gilts.

Effect of dietary energy in gestation on reproductive performance of gilts.

Reproductive performance of gilts fed diets low in protein during gestation and lactation.

Reproductive performance of gilts fed diets low in protein during gestation and lactation.

Effects of energy intake and dichlorvos during gestation on reproductive performance of gilts and some chemical characteristics of the offspring.

Effects of energy intake and dichlorvos during gestation on reproductive performance of gilts and some chemical characteristics of the offspring.

Diet consumption, bodyweight change, estrus inhibition and reproductive performance in gilts fed a dithiocarbamoylhydrazine (ICI 33828).

Diet consumption, bodyweight change, estrus inhibition and reproductive performance in gilts fed a dithiocarbamoylhydrazine (ICI 33828).

Effects of a Dietary Combination of Diethylstilbestrol and Methyltestosterone on Reproductive Performance of Gilts

Effects of a Dietary Combination of Diethylstilbestrol and Methyltestosterone on Reproductive Performance of Gilts

Reproductive Performance of Gilts following Heat Stress Prior to Breeding and in Early Gestation

Reproductive Performance of Gilts following Heat Stress Prior to Breeding and in Early Gestation

Influence of Energy Intake on Reproductive Performance of Gilts

Influence of Energy Intake on Reproductive Performance of Gilts

Prenatal Reproductive Performance in Gilts Fed Low Levels of Stilbestrol in a Legume-Free and an Alfalfa Ration

In five dry-lot experiments, gilts were fed legume-free or 18% alfalfa, breeding-gestation rations containing levels of 0.29, 0.58 and 3.0 mcg. of stilbestrol per lb. A feeding period of 30 days preceded breeding. The gilts were slaughtered during gestation and observations made on the number of corpora lutea and live young. Lower ovulation rates were associated with the inclusion of the three levels of stilbestrol in the legume-free ration. The number of live young and percent corpora lutea represented as live embryos was consistently reduced when 0.29 and 0.58 mcg. of stilbestrol per lb. were included in the legume-free ration. The average number of live embryos and percent corpora lutea represented as live embryos observed in gilts fed 3.0 mcg. of stilbestrol per lb. of legume-free ration exceeded that of the control group in one experiment but were lower in the succeeding experiment. The addition of stilbestrol to the 18% alfalfa ration did not influence reproductive performance as measured. Corpora lutea and live young were positively correlated with weight of the gilts regardless of age.

The Relationship between Femininity Ratings and Reproductive Performance in Gilts

FOR many years livestock breeders have given considerable attention to masculinity and femininity in the selection of animals to add to or to retain in their breeding herds and flocks on the contention that animals possessing these somewhat intangible qualities to the highest degree are the best breeders. Likewise, livestock judges have laid great stress upon strong development of masculinity and femininity on the premise that such qualities serve as a good partial index to the breeding worth of the animals. A review of existing literature reveals many statements that express such views; however, there is apparently a complete absence of controlled data to substantiate or to refute such claims. Since reproductive data were to become available on 79 gilts in three experiments designed to study the effects of certain nutritional and management factors on reproductive performance, it was decided to assign femininity ratings to these gilts and to study the correlation of these ratings with reproductive performance in an effort to secure controlled data on the relationship between femininity and reproductive performance.

Some Effects of Source of Protein and an Antibiotic on Reproductive Performance in Gilts

Some Effects of Source of Protein and an Antibiotic on Reproductive Performance in Gilts