Biomedical subjects

R R Maurer

Publications and source records attributed to R R Maurer.

At least 19 recordsLinked to original sources

PubMed1994

Follicular development, oocyte viability and recovery in relation to follicular steroids, prolactin and glycosaminoglycans throughout the estrous period in superovulated heifers with a normal LH surge, no detectable LH surge, and progestin inhibition of LH surge.

Estrous cycles of heifers (n = 137) were synchronized with prostaglandin (PGF2 alpha) and follicular development stimulated with follicle stimulating hormone. Twenty-eight animals were administered Norgestomet implants 12 hr prior to the initial PGF2 alpha injection to suppress the LH surge that initiates ovulation. Animals were ovariectomized every 12 hr after the initial PGF2 alpha (7-9/time, 12-108 hr and at 192 and 240 hr post PGF2 alpha) and divided into three treatment groups to consist of: 1) animals exhibiting a normal luteinizing hormone (LH) surge (n = 86), 2) animals in which no LH surge was detected (n = 23), and 3) suppression of the LH surge via Norgestomet implants (72-108 hr, n = 28). Follicular diameter was measured and follicular fluid was collected for analysis of prolactin, estradiol, progesterone and glycosaminoglycan concentrations. Progesterone concentrations were increased in animals exhibiting an LH surge as compared to animals in which no LH surge was detected; primarily in large follicles (> 8 mm diameter) after the LH surge. Animals not exhibiting an LH surge also had increased follicular progesterone concentrations compared to Norgestomet-implanted animals (242.3 +/- 36.3 vs 86.7 +/- 6.4 ng/ml, respectively, P < .01), indicating some LH stimulation. Follicular estradiol in animals exhibiting an LH surge increased up to the time of LH surge detection and then declined whereas animals with no LH surge detected had follicular estradiol concentrations that declined after the PGF2 alpha injection. No differences were noted between those that did not exhibit an LH surge or in which the LH surge was suppressed with Norgestomet in relation to follicular estradiol concentrations. Follicular estradiol concentrations increased with follicular size in all treatment groups (P < .01). Follicular concentrations of prolactin were increased in small follicles (P < .05; < or = 4 mm diameter) and follicular prolactin increased from 12 to 36 hr post PGF2 alpha injection, then declined after the LH surge. Follicular glycosaminoglycan concentrations decreased with increases in follicular size (P < .01) and were higher in animals that did not exhibit an LH surge (P < .01). No differences in follicular glycosaminoglycans were noted between Norgestomet-implanted animals and those not exhibiting an LH surge. In the animals representing days 4 and 6 of the subsequent estrous cycle (192 and 240 hr post PGF2 alpha), numbers of small-sized follicles were increased. Follicular progesterone and estradiol concentrations were related to atretic large follicles unovulated from the prior estrus and a new wave of growth in small and medium follicles.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗

PubMed1994

Cumulus and oocyte maturation and in vitro and in vivo fertilization of oocytes in relation to follicular steroids, prolactin, and glycosaminoglycans throughout the estrous period in superovulated heifers with a normal LH surge, no detectable LH surge, and progestin inhibition of LH surge.

Crossbred heifers (n = 103) were synchronized to estrus with prostaglandin (PGF2 alpha) and superovulated with follicle stimulating hormone (FSH-P). Animals were ovariectomized every 12 hr after the PGF2 alpha injection (n = 7 to 9/time) up to 108 hr to monitor the follicular, hormonal, and oocyte changes associated with follicular development and ovulation. Twenty-eight animals were implanted with Norgestomet implants 12 hr before PGF2 alpha and ovariectomized at 72, 84, 96, and 108 hr post PGF2 alpha injection to monitor effects of progesterone and suppression of the luteinizing hormone (LH) surge on oocyte maturation and quality. Follicular fluid was collected and analyzed for progesterone, estradiol, prolactin, and glycosaminoglycan content in conjunction with cumulus maturation and nuclear stage of oocyte maturation. Analysis of in vivo matured oocytes by in vitro fertilization was carried out at 60, 72, 84, and 96 hr post PGF2 alpha and in vitro matured oocytes at 12 to 108 hr post PGF2 alpha. No developmental changes in cumulus cells surrounding the oocyte of small follicles was noted (< or = 4 mm dia) indicating a static population. Medium (> 4 < or = 8 mm) and large size (> 8 mm) follicles developed to the corona radiata and loose cumulus stages in animals in which an LH surge was detected but cumulus status remained primarily in the tight cumulus stage for animals without an LH surge. The estradiol-to-progesterone ratio for tight cumulus (TC), corona radiata (CR), and loose cumulus (LC) stages was 1.8 +/- .1, 1.0 +/- .1, and .4 +/- .2, respectively (P < .01). Nuclear maturation of oocytes in small follicles from animals without a detectable LH surge seem to indicate early maturation (48 to 72 hr post PGF2 alpha) in conjunction with a high percent of degenerate oocytes not seen in animals exhibiting an LH surge. Oocytes from medium size follicles matured to germinal vesicle breakdown (GVBD) and early meiosis (metaphase I; MI) stages of development in all treatments. Most oocytes were degenerate in Norgestomet-implanted animals. Oocytes from large follicles (> 8 mm dia) from animals exhibiting an LH surge were in MI and metaphase II (MII) stages (48 to 84 hr post PGF2 alpha) in preparation of ovulation whereas oocytes from animals not exhibiting an LH surge had oocytes that early matured to MII (48 to 72 hr post PGF2 alpha), later regressing to degenerate oocytes (84 to 108 hr). Follicular progesterone, estradiol, and prolactin increased with oocyte maturation, particularly in medium and large follicles.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗

PubMed1993

Protein restriction during pregnancy affects postnatal growth in swine progeny.

Protein deficiency during pregnancy affects fetal development. The critical period, when the fetus is most susceptible to maternal protein deficiency and its effect on neonatal growth, is unknown. Therefore, we studied the effect of a protein-restricted diet during early and late pregnancy and throughout pregnancy on growth of pigs from birth to market weight. Sows were fed a control (13% protein) or protein-restricted (0.5% protein) diet throughout pregnancy or protein-restricted diet from d 1 to 44, then control diet to term or control diet from d 1 to 81, then the protein-restricted diet to term. In Experiment 1, birth weights were measured, and 12 pigs/diet group were weaned at 4 wk and raised to market weight. Feeding the protein-restricted diet throughout pregnancy reduced birth and slaughter weights, whereas the control followed by protein-restricted and protein-restricted followed by control diets reduced only birth weight relative to controls. Indices of carcass lean were reduced in the protein-restricted piglets, with carcass fat not affected. In Experiment 2, control and control-protein-restricted litters were reduced to six piglets and 3/litter cross-fostered to a sow of the other treatment group. After weaning at 4 wk, 4 piglets/group were individually fed to 8 wk. The control and control followed by protein-restricted diet fed piglets had similar weights at birth, but piglets raised by a control-protein-restricted sow tended to weight less at weaning than their littermates raised by a control sow. After weaning, these piglets had greater feed intakes relative to other groups and there were no weight differences by 8 wk.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1992

Influence of sexual maturity of donor on in vivo survival of transferred porcine embryos.

A study was conducted to determine whether embryos recovered from first-estrous (pubertal) and second-estrous gilts differed in survival when transferred to first- or third-estrous recipients. Embryos were recovered surgically from first- and second-estrous donors 48-72 h postmating and 6-10 normal embryos/zygotes (1-4 cells) were transferred to oviducts (3-5 embryos/ampulla) of nonmated synchronous first- (n = 40) or third- (n = 15) estrous recipients. Blood samples were collected from the jugular vein of recipient gilts on Days 3, 12, and 30 of gestation and the sera were analyzed for progesterone and free (unconjugated) estrogens by use of radioimmunoassays. Recipient gilts were subsequently slaughtered between Days 30 and 40 to assess embryonic losses. Mean number of ovulations was lower among first-estrous vs. third-estrous recipients (8.9 +/- 0.7 vs. 11.4 +/- 0.7; p < 0.05). Percentage of recipients that maintained pregnancy was similar between first- and third-estrous gilts (67.5 vs. 60.0%) and recovery of total conceptuses (normal and degenerating) resulting from transfer of one-cell- and cleavage-stage embryos did not differ among first- vs. third-estrous gilts (76.1 vs. 78.2%). Similarly, percentage of viable fetuses in first-estrous gilts that were pregnant from transfer of one-cell- and cleavage-stage embryos was not different from that of third-estrous gilts (69.3 vs. 75.6%). Percentages of total conceptuses and viable fetuses in first- and third-estrous gilts that were recipients of cleavage-stage embryos only also did not differ (p > 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Age Factors↗

PubMed1992

Endocrine changes in beef heifers superovulated with follicle-stimulating hormone (FSH-P) or human menopausal gonadotropin.

The effects of superovulatory treatment (FSH-P vs human menopausal gonadotropin, HMG) and of route of administration (i.m. vs. i.v.) of prostaglandin F2 alpha (PGF2 alpha) on hormonal profiles were determined in 32 Angus x Hereford heifers. Heifers were superstimulated with either FSH-P (total of 26 mg) or HMG (total of 1,050 IU) beginning on d 9 to 12 of an estrous cycle and PGF2 alpha (40 mg) was administered at 60 and 72 h after the beginning of superovulatory treatments. Heifers were artificially inseminated three times at 12-h intervals beginning 48 h after PGF2 alpha treatment. Blood serum samples were collected immediately before treatments began, at 12-h intervals during the first 60 h, each 4 h during the next 96 h, and each 12 h until day of embryo collection. Concentrations of LH and FSH were not affected by hormone treatments, route of PGF2 alpha injection, or interactions between them. Estradiol-17 beta (E2-17 beta) levels were higher (P less than .05) in HMG- than in FSH-P-treated heifers 60 h after gonadotropin treatment. Peak concentration of E2-17 beta occurred earlier (P less than .05) in HMG- than in FSH-P-treated heifers and earlier in heifers injected with PGF2 alpha i.m. than in those injected i.v. Progesterone concentrations were not influenced by treatment or route of PGF2 alpha administration, but were affected (P less than .01) by the interactions between treatment and route of PGF2 alpha administration. Progesterone declined to basal levels earlier in the FSH-P- than in the HMG-treated heifers.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1992

Response of fetal and newborn piglets to maternal protein restriction during early or late pregnancy.

Dietary protein restriction during pregnancy has an adverse effect on progeny development, although the importance of the time at which the nutritional insult occurs is unclear. The objective in our study was to test the hypothesis that severe protein restriction during the first trimester of swine pregnancy has a greater detrimental effect on fetal development than restriction in late pregnancy. On the day of mating, primiparous swine were assigned to control (C, 13% protein) or protein-restricted (PR, 0.5% protein) diets and fed in 4 regimens: 1) C diet throughout pregnancy (114 +/- 2 days) (n = 5), 2) PR diet to day 44, C diet to parturition (n = 6), 3) C diet to day 80, PR diet to parturition (n = 8), and 4) PR diet throughout pregnancy (n = 6). In addition, 6 pigs fed C and 7 pigs fed PR diets were killed at day 44 to assess placental and fetal development. Maternal diet had no effect on placental or fetal weight, crown-rump length, or heart girth circumference in 44-day fetuses. Mean birth weight of newborn piglets was 1462, 1291, 1262, and 1064 g for C, PR:C, C:PR, and PR groups, respectively (C greater than PR:C = C:PR greater than PR, p less than 0.01). Plasma total protein and albumin were less (p less than 0.01) in PR than in PR:C and C:PR; all three groups were less than C (p less than 0.01). Liver weight and total liver protein, RNA, and DNA followed the same pattern (C greater than PR:C = C:PR greater than PR, p less than 0.05). Longissimus muscle total protein, RNA, and DNA were greater in group C than in all other groups (p less than 0.01). Maternal protein restriction during early pregnancy produced less developmental impairment than restriction throughout pregnancy, but the magnitude of impairment was similar to that produced by restriction during only the third trimester. The effects of early restriction were manifested at birth, even though none of the indices of stunting were observed at 44 days when the maternal protein restriction was ended. Whether the effects of early versus late restriction show the same mechanism of action has not been determined.

Animals↗

PubMed1991

The effects of recombinant bovine interferon-alpha on fertility in ewes.

Recombinant bovine interferon-alpha(I)1 (rBolFN-alpha) may be useful for enhancing fertility in sheep because it has extensive sequence homology with ovine trophoblast protein-1. To test the effectiveness of rBolFN-alpha, several experiments were performed in which bred females were given intramuscular injections of rBolFN-alpha around the time of maintenance of the corpus luteum. Treatment with rBolFN-alpha enhanced the fertility of ewes that were bred via natural service or embryo transfer of whole or demi-embryos. Interferon treatment was successful in enhancing lambing rate if injections were given twice daily from Days 11 to 18, 12 to 14, 12 to 15 or 12 to 16. Overall, the lambing rate for ewes bred via natural service was 94/126 (74.6%) for control ewes and 101/126 (80.2%) for rBolFN-alpha treated ewes. Litter size was not affected by treatment. Interferon treatment was not successful in increasing the lambing rate if given as a single injection on Day 12 or as a series of once-daily injections from Days 11 to 16. These results demonstrate that rBolFN-alpha can increase the lambing rate in ewes.

Journal Article↗

PubMed1991

Superovulation and embryo quality in beef cows using PMSG and a monoclonal anti-PMSG.

The long half-life of pregnant mare serum gonadotrophin (PMSG) reduces its application in the superovulation of cattle; thus, a monoclonal antibody to PMSG (anti-PMSG) was administered at the onset of estrus to increase the number of transferable embryos. Angus, Hereford and Angus x Hereford cows (n = 149) 3 to 9 yr old were assigned randomly to one of three dosages of PMSG (1500, 3000 or 6000 IU) with or without an equivalent dosage of anti-PMSG. Embryos were collected nonsurgically on Day 8 (estrus = Day 0), and all cows were ovariectomized on Day 9. The percentage of cows exhibiting estrus and ovulating decreased (P<0.05) with an increasing dosage of PMSG (82, 76 and 44% for 1500, 3000 and 6000 IU, respectively). Ovarian and total corpora lutea (CL) weight increased (P<0.001) linearly as PMSG dosage increased, but were reduced (P<0.001) curvilinearly by anti-PMSG, resulting in a PMSG by anti-PMSG interaction (P<0.001); the interaction was also significant (P<0.05) for ovulation rate (14.0 vs 14.3, 21.5 vs 24.4 and 29.2 vs 6.6 CL for 1500, 3000 and 6000 IU PMSG, without vs with anti-PMSG, respectively). Anti-PMSG increased (P<0.001) the number of small ovarian follicles (1 to 3 mm diameter) and decreased (P<0.001) the number of large follicles (>10 mm) at ovariectomy; the number of large follicles increased (P<0.001) with PMSG dosage. The number of total and transferable embryos recovered did not differ among PMSG and anti-PMSG dosages; however, the percentage of transferable embryos decreased (P<0.01) with increasing PMSG dosage. In general, neither PMSG dosage nor anti-PMSG influenced embryo quality.

Journal Article↗

PubMed1991

Fetal organ response to maternal protein deprivation during pregnancy in swine.

To test the hypothesis that maternal protein deprivation in early pregnancy retards body and organ growth of 63-d (midterm) pig fetuses, 16 primiparous domestic four-way crossbred swine were fed a diet adequate in protein (13% protein) (A) or a protein-restricted (0.7% protein) diet (PR) from d 1 to 63 of pregnancy or to parturition. Maternal body weight, plasma protein, hematocrit, and heart and spleen weights were reduced, and indices of body fatness were increased by the PR diet. Fetal body weights were reduced and fetal placental weights were increased at d 63 by protein restriction. Length from crown to rump and weights of liver, kidney, gastrointestinal tract, and cerebrum were lower in PR than in A fetuses. Concentrations of protein, RNA and DNA in liver, cerebrum and longissimus muscle were unaffected by maternal diet, but total amounts of all three constituents in liver and cerebrum were lower in PR than in A. Relative organ weights were similar in A and PR fetuses except that kidneys and gastrointestinal tract were greater in A fetuses. Newborn body weights and absolute organ weights were generally lower in PR than in A, but relative weights were similar. The observed reduction in body and organ weights and amounts of protein, RNA and DNA in 63-d fetuses and newborn progeny of PR swine establishes that the stunting effect of maternal protein restriction can be initiated by midterm, preceding the period of most rapid accretion of body tissues during prenatal life in the pig.

Analysis of Variance↗

PubMed1991

Characterization of thymosin alpha 1 and beta 4 during the bovine estrual period: effects of elevated estradiol and progestin.

At present, there is a renewed interest in thymic function and its secretions in relation to endocrine control and reproductive function. In an initial experiment, 60 crossbred heifers (18-20 mo) were detected in estrus and assigned to control or FSH superovulatory groups. On Days 7-14 of the subsequent estrous cycle, FSH was administered for 5 days and prostaglandin F2 alpha (PGF2 alpha) was administered at 48 and 60 h after the initial FSH injection. Control animals received only PGF2 alpha injections between Days 9 and 15 of the cycle. Blood samples were collected from all animals at the time of PGF2 alpha injection and every 12 h thereafter to 72 h post PGF2 alpha injection. In a subsequent experiment, 103 crossbred heifers (16-18 mo) were superovulated with FSH and synchronized to estrus with PGF2 alpha administered 60 h after the initial FSH injection. Twenty-eight of the heifers received Norgestomet implants 12 h prior to the initial PGF2 alpha injection to inhibit the LH surge. Blood samples were collected from animals at 12-h intervals until the PGF2 alpha injection and every 6 h thereafter until 108 h post PGF2 alpha treatment. Although thymosin beta 4 concentrations did change over the estrual period, no differences were noted between control and superovulatory animals in the initial experiment even though estradiol concentrations were increased tenfold from the FSH stimulated ovary. In the second experiment, thymosin beta 4 and alpha 1 increased as the estrual period progressed and decreased (p less than 0.05) subsequent to the LH surge. (ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1991

Prenatal and postnatal maternal contributions to reproductive, maternal, and size-related traits of beef cattle.

Brown Swiss-Hereford (BS-H) reciprocal cross embryos were transferred to BS and H recipient cows and Red Poll-Angus (RP-A) reciprocal cross embryos were transferred to RP and A recipient cows to estimate the relative contributions of ovum cytoplasm and uterine influences to prenatal maternal effects. Calves resulting from embryo transfers (ET) were weaned early (3 to 5 d). Reciprocal cross mating also were made by natural service (NS) between BS and H and between RP and A breeds; part of the offspring were weaned at 3 to 5 d, and the remainder nursed their dams to an age of 150 to 180 d. This was done to estimate breed differences in prenatal and postnatal effects combined and to separate the effects of prenatal maternal influences from postnatal maternal influences of these breeds. Females produced in both ET and NS parts of the experiment were retained to produce three calf crops to an age of about 4.5 yr. The following traits were analyzed: percentage of conception rate; percentage of calf survival; percentage of calves produced per cow exposed; birth and weaning weights of calves produced; and periodic weights, heights, and condition scores of females to an age of 4.5 yr. Neither breed of donor (cytoplasmic influence) nor breed of recipient (uterine influence) had consistently important effects on the traits evaluated. In NS matings, differences between reciprocal crosses were small for most of the traits evaluated. Method of rearing (nursed vs weaned at 3 to 5 d) had no effect on reproductive and maternal traits for RP-A reciprocal cross females, but females that nursed generally were heavier, were taller, and had higher condition scores at most ages than early-weaned females. For the BS-H reciprocal cross, early-weaned females were favored over females reared by their dams in percentage of calves produced per cow exposed, but the method of rearing did not affect other reproductive or maternal traits. BS-H reciprocal cross females that nursed their dams were heavier at 550 d and were heavier and had higher condition scores at an age of 34 mo than early-weaned females.

Animals↗

PubMed1990

Changes in the glycosylated and nonglycosylated forms of prolactin and growth hormone in lean and obese pigs during pregnancy.

The concentrations of glycosylated (G-PRL) and nonglycosylated (non-G-PRL) forms of PRL and GH were measured during pregnancy in pigs of lean and obese (high backfat thickness) lines. Pregnant sows of the two genetic lines were killed, in groups of five to eight, at 60, 75, 90, and 105 days of gestation, and their pituitary glands and plasma were analyzed for the two hormones by immunoblotting, lectin-binding, and RIA techniques. In both lean and obese pigs, pituitary concentrations of G-PRL and non-G-PRL increased with advance in pregnancy, but there were no significant changes in either form of pituitary GH. Plasma concentrations of radioimmunoassayable PRL also increased with advance in pregnancy, with no consistent changes in serum GH concentrations. The dominant PRL constituent in plasma during the second half of pregnancy was G-PRL, and its concentration either increased or remained constant with advance in pregnancy. In contrast, plasma non-G-PRL concentrations decreased with advance in pregnancy in both lines of pigs, resulting in a steady rise in the plasma G-PRL/PRL ratio toward term. Compared to lean pigs, obese pigs had less radioimmunoassayable PRL and GH in their plasma and less GH (glycosylated as well as nonglycosylated) in their pituitary glands, but obese pigs had more G-PRL in their pituitary glands than lean pigs, and their plasma G-PRL levels tended to be higher and non-G-PRL levels lower than those of lean pigs. Pituitary concentrations of non-G-PRL in the two lines of pigs were similar. Overall, the results show a preponderance of G-PRL over non-G-PRL in the plasma of pregnant sows, with a preferential secretion of the glycosylated form during the latter half of pregnancy. Furthermore, they indicate a prevalence of higher G-PRL/PRL ratios in the pituitary glands of obese than lean pigs. These findings raise the possibility of a functional role for the glycosylated variant of PRL in the initiation and/or maintenance of events associated with pregnancy and obesity in the pig.

Animals↗

PubMed1990

Contributions of ovum cytoplasm, uterine environment and postnatal environment to maternal effects in beef cattle.

In the first part of the experiment, embryos of Brown Swiss-Hereford (BS-H) reciprocal crosses were transferred to BS and H recipient cows and embryos of Red Poll-Angus (RP-A) reciprocal crosses were transferred to RP and A recipient cows. Calves resulting from embryo transfers (ET) were weaned early (3 to 5 d). Males were castrated and their growth, feed efficiency and carcass composition were recorded. In the second part of the experiment, matings to produce reciprocal crosses were made by natural service (NS) between BS and H and between RP and A. Some of the offspring were weaned at 3 to 5 d; the remainder nursed their dams to an age of 150 to 180 d. Growth after 200 d, feed efficiency and carcass data were recorded on steers. Females produced in both parts of the experiment were reared for breeding, and post-200-d growth and age at puberty were recorded. Neither breed of recipient (uterine influence) nor breed of donor (cytoplasmic influence) had important effects on growth or carcass traits. Large differences were observed for most growth and carcass traits between offspring that were weaned early and those that nursed their dams. Effects of early weaning were greater in progeny of Brown Swiss and Red Poll dams than in progeny of Angus and Hereford dams. Prenatal maternal influences (e.g., ovum cytoplasm and uterine influence) are relatively small in comparison with postnatal maternal influences in contributing to maternal effects in beef cattle.

Animals↗

PubMed1990

Ontogeny of glycosylated and nonglycosylated forms of prolactin and growth hormone in porcine pituitary during fetal life.

Although prolactin (PRL) and growth hormone (GH) were long considered to be nonglycoprotein hormones of the pituitary, glycosylated forms of these hormones have nevertheless been discovered in recent years. We determined the ontogeny of glycosylated and nonglycosylated PRL and GH during the fetal life of the pig, an animal in whose pituitary the glycosylated variant of PRL has been found in high (40%) concentrations. Swine fetuses of both sexes from lean and obese animals of Duroc x Yorkshire crosses were examined at 60, 75, 90, and 105 days of age. No appreciable differences related to sex or phenotype were noted in any of the parameters measured; therefore, data for all animals within an age group were combined. Such averages revealed considerable amounts of GH in the fetal pituitary as early as 60 days of age, whereas PRL, although detectable by radioimmunoassay and immunoblotting at all ages tested, was not present in significant amounts until 105 days of age. From its first appearance, however, almost 70% of the PRL synthesized in the fetal pituitary was of the glycosylated type. In contrast to PRL, both the glycosylated and nonglycosylated forms of GH showed a steady rate of increase throughout the observation period. The immunoblotting analyses also revealed in the fetal pituitary several intensely staining 8- to 12-kDa PRL-immunoreactive peptides of unknown identity. The occurrence of significantly greater concentrations of glycosylated PRL than of non-glycosylated PRL in the fetal pituitary during late gestation offers new possibilities for the role of this hormone in the development of swine fetus.

Animals↗

PubMed1990

Reduced mature size in progeny of swine severely restricted in protein intake during pregnancy.

The objective was to determine the effects of maternal gestation diet on mature body and organ size and composition of progeny. Female progeny of swine fed daily 1.8 kg (6,000 kcal DE) of a semipurified diet containing less than 0.5% protein (PR), 1.8 kg (6,000 kcal) of a standard maize-soybean meal-based gestation diet (C) or 0.6 kg (2,000 kcal DE) of C diet to d 70 of gestation and 1.8 kg (6,000 kcal DE) from d 71 to parturition (R) were used. They were fed ad libitum a standard maize-soybean meal-based growing diet to age 25 wk, then continued on limited feed intake to age 62 wk, then returned to ad libitum intake to age 119 wk. Body weight and ultrasonically determined subcutaneous backfat depth were recorded at 62, 79, 97, 105 and 119 wk of age and indices of body composition and organ weights were recorded on carcasses of animals killed at age 119 wk. Progeny of PR dams were permanently stunted in mature body weight and in weights of eviscerated carcass, heart, liver, kidneys, stomach and small intestine, but not in cerebrum, cerebellum weights or RNA and DNA content. It is concluded that severe protein restriction during gestation in swine resulted in permanent whole body weight stunting of progeny but that weights and total protein, RNA and DNA content of cerebrum, cerebellum and RNA and DNA concentration of longissimus muscle were unaffected.

Aging↗

PubMed1989

Exposure of bovine embryos to trypsin during washing does not decrease embryonic survival.

The objective of this study was to assess whether the exposure of zona pellucida-intact bovine embryos to the proteolytic enzyme, trypsin, during embryo washing has a detrimental effect on their subsequent survival and development. Embryos were collected nonsurgically from superovulated cows (n = 19) 7.5 d after insemination. Grade 1 and Grade 2 embryos were washed 12 times in modified Dulbecco's phosphate buffered saline (PBS) containing 0.4% bovine serum albumin (BSA), or in a series of five washes in BSA-PBS (without Ca++ and Mg++), two in 0.25% trypsin in Hank's solution (without Ca++ and Mg++) and five in PBS-BSA medium. Within 30 min after washing, embryos were either transferred nonsurgically into recipient cows, 7 to 8 d post estrus, or cryopreserved and transferred later. Frozen-thawed embryos from five of the donors were cultured for 72 h in vitro and their development was evaluated. Pregnancy rates did not differ (P>0.1) between recipient cows receiving control-washed and trypsin-washed embryos transferred fresh (51.0 vs 56.3%). However, pregnancy rates were higher (P<0.05) for frozen-thawed embryos treated with trypsin before cryopreservation than for frozen-thawed, control-washed embryos (68.2 vs 38.5%). Survival and development of embryos in vitro after cryopreservation did not differ between embryos subjected to the control- and trypsin-wash procedures. These results suggest that exposure of bovine embryos to trypsin for 2 to 3 min during washing did not have a detrimental effect on embryonic development, but may have enhanced cryopreservation of the embryos.

Journal Article↗

PubMed1989

Ovarian responses to intramuscular or intravenous administration of prostaglandin F2 alpha in control and FSH-treated beef heifers.

Sixty Simmental crossbred heifers 18 to 20 mo of age were detected in estrus and assigned at random to a 2 x 2 factorial design study with 30 controls, and 30 given FSH. Half of each group was given prostaglandin F2 alpha (PGF) i.v. and the rest i.m. Injections of follicle-stimulating hormone were started on d 7 to 14 of an estrous cycle and continued for 5 d or until ovariectomy; PGF was administered either i.v. or i.m. at 48 (25 mg) and 60 (15 mg) h after the initial FSH injection. Control females received a similar PGF treatment on a day between d 9 and 15 of the estrous cycle. Blood samples were collected from all animals immediately before PGF administration and every 12 h thereafter until ovariectomy. Within each of the four experimental subgroups, ovariectomies were performed at either 24, 48 or 72 h (five/time group) after initial PGF injection. Ovarian and corpus luteum (CL) weights were recorded as well as number and size of follicles and number of ovulations. Regression of the CL was slower (P less than .05) after administration of PGF i.v. than i.m. (CL weight was 2.6 vs 3.3 +/- .2 g for i.m. and i.v. groups, respectively). Exogenous FSH increased estradiol-17 beta (E2) concentrations, and FSH-treated heifers had more (P less than .05) early ovulations than control heifers did. Ovulations in FSH-treated heifers had begun to occur by 24 h after i.v. and i.m. PGF injection.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1988

Decreased fertility in related females heterozygous for the 1/29 chromosome translocation.

Eighteen heifers and 120 cows which were descendants of a presumed 1/29 carrier Simmental bull were karotyped. Nine heifers (50%) and 48 cows (40%) were found to be heterozygous for the 1/29 translocation (59, XX, t(1q;29q)). The other animals were chromosomally normal (i.e., 60, XX) or not karotyped. The 48 1/29 cows were compared with 72 chromosomally normal cows with regards to days to first conception, calving interval, percentage of calves conceived, percentage of calves weaned and production efficiency (% calved conceived x % calved weaned). Nine carrier heifers were compared to the nine noncarrier heifers as to pregnancy status. Carrier, noncarrier and nonkarotyped relatives were compared to each other and to contemporary females with regard to pregnancy status at their initial exposure to males. The percentage of calves conceived (calving efficiency) in the 72 noncarrier and the 48 females heterozygous for the 1/29 translocation were 81.5 and 74.8%, respectively (P<0.07). Although days to first conception was longer and percentage of calves weaned and production efficiency were lower in the female heterozygous for the 1/29 translocation, the differences were not statistically different (P>0.10) from the noncarriers. Pregnancy rate was 44.4 and 66.7% (P>0.10) for nine carrier and nine noncarrier heifers, respectively. The pregnancy rate of carrier (65.4%), noncarrier (73.2%) and nonkarotyped (77.8%) relatives of this sire at their mating as yearlings, did not differ (P>0.10). The pregnancy rate as yearlings of carrier females (65.4%) and contemporary heifers (79.8%) did differ (P<0.05). Comparing the pregnancy rate as yearlings of all descendants (72.0%) of the Simmental sire to contemporary heifers (79.8%), a significant decrease (P<0.05) was found indicating that fertility of this sire may have been lower than other sires or that other factors beside the translocation affected fertility.

Journal Article↗