Biomedical subjects

M C Lucy

Publications and source records attributed to M C Lucy.

88 records · Page 5Linked to original sources

PubMed1993

Secretion of PGF2alpha and oxytocin during hyperthermia in cyclic and pregnant heifers.

The effects of acute heat stress (HS) and oxytocin (OT) injection on plasma concentrations of PGF2alpha and OT were examined in cyclic (C; n = 15) and pregnant (P; n = 11) dairy heifers. On Day 17 of synchronized estrous cycles, animals were randomly assigned to either thermoneutral (TN; 20 degrees C, 20% RH) or HS (42 degrees C, 60% RH) chambers. The jugular vein of each heifer was cannulated and blood samples collected hourly for 4 h, then every 15 min for an additional 3 h. Oxytocin (100 IU) was injected (IV) 5 h after the start of blood collection. Plasma samples were assayed subsequently for concentrations of 13,14-dihydro-15-keto PGF2alpha (PGFM) and OT. During the 7-h experiment, body temperature of HS heifers reached 41.2 degrees C as compared to 38.5 degrees C in control heifers. Plasma concentrations of PGFM increased (P<0.05) and peaked 30 min after OT injection in C (890 pg/ml) and P (540 pg/ml) heifers. In C heifers, heat stress failed to alter PGFM concentrations either before or after OT injection. In the P group, PGFM concentrations following OT injection tended to be higher in HS heifers were further TN heifers (peak values of 690 vs. 410 pg/ml). Pregnant TN and HS heifers were further classified as responders or non-responders to OT challenge according to a cutoff value for PGFM of 193 pg/ml (overall mean of C heifers minus 1 SD). Five of six HS and one of five TN pregnant heifers were classified as responders (P<0.06). Oxytocin concentrations in plasma prior to injection of exogenous OT were not affected by HS or pregnancy status. It is concluded that in C heifers, acute HS in vivo does not cause any further rise in PGF2alpha secretion. However, in P heifers, HS appears to antagonize suppressive effects of the embryo on uterine secretion of PGF2alpha, as indicated by the larger proportion of P heifers responding to OT challenge.

Journal Article↗

PubMed1993

Variants of somatotropin in cattle: gene frequencies in major dairy breeds and associated milk production.

The amino acid sequence of bovine somatotropin (bST) varies at position 127 where either valine or leucine is found. The frequencies of leucine127 and valine127 bST gene alleles in cows (n = 302) and sires (n = 70) from major dairy breeds (Holstein, Brown Swiss, Guernsey, Jersey, and Ayrshire) were determined using DNA extracted from whole blood or spermatozoa. A 428 base pair fragment of the bST gene was amplified using polymerase chain reaction (PCR) and variants of the bST gene were detected as polymorphisms by Alu I restriction endonuclease digestion of PCR products. Restriction enzyme DNA fragments for the leucine127 variant were 265, 96, 51, and 16 base pair and for the valine127 variant were 265, 147, and 16 base pair as a polymorphism of bST was present in the 147 base pair DNA fragment. Frequencies of leucine127 and valine127 alleles for cows (n = 302) were 1.0 and 0 for Brown Swiss, .93 and .07 for Holstein, .92 and .08 for Guernsey, .79 and .21 for Ayrshire, and .56 and .44 for Jersey, respectively. In Holstein sires used for artificial insemination (n = 70), the frequency of leucine127 and valine127 alleles was .96 and .04. Estimates of transmitting ability for milk production tended to be greater for Holstein cows that were homozygous for leucine127 bST and Jersey cows that were homozygous for valine127 bST whereas Holstein sires with different bST genotypes were similar. In summary, frequencies of alleles for the bST gene were not similar in different dairy breeds and estimates of milk production were correlated with bST gene variant in cows but not sires.

Alleles↗

PubMed1993

Immunohistochemical and nucleic acid analysis of somatotropin receptor populations in the bovine ovary.

Ovaries were analyzed for somatotropin receptor protein and mRNA through use of immunohistochemistry, solution hybridization/nuclease protection, Northern blotting, and reverse transcriptase polymerase chain reaction (RT-PCR). As indicated by immunoperoxidase staining, CL expressed immunoreactive somatotropin receptor (positive stain). Ovarian stroma, connective tissue, endothelium, and erythrocytes did not express somatotropin receptor (negative stain). Within the CL, somatotropin receptor protein was expressed primarily in large luteal cells whereas small luteal cells were negative. Most follicles (1-5 mm, after fixation) were negative for somatotropin receptor. On the basis of solution hybridization/nuclease protection, the mRNA for somatotropin receptor was found in greatest abundance in CL and large luteal cells and was nearly undetectable in small luteal cells or follicles (class 1, 3-5 mm; class 2, 6-9 mm; and class 3, > or = 10 mm). Northern blotting of mRNA for somatotropin receptor showed expression of somatotropin receptor mRNA transcripts in whole ovary (4.7 and 4.4 kb), CL (4.7 and 4.4 kb), and liver (4.4 kb); and RT-PCR amplified a single amino acid coding region for somatotropin receptor in CL and liver. In summary, somatotropin receptor (both immunoreactive protein and mRNA) is found primarily in the large luteal cell, and lesser amounts of the expressed receptor or its message are found in the follicle. Alternative sizes of mRNA for somatotropin receptor suggest novel mRNA processing in the bovine ovary.

Animals↗

PubMed1993

Effects of recombinant bovine somatotropin (sometribove) on ovarian function in lactating and nonlactating dairy cows.

Metabolic and ovarian responses of lactating and nonlactating cows to recombinant bST (sometribove) were measured. Eighteen lactating cows (60 to 100 d postpartum) and 6 nonlactating cows (> 400 d postpartum) were injected daily with bST or saline during one of two periods. Concentrations of hormones and metabolites were measured in plasma, and ultrasonography was used to quantify ovarian follicular growth. Concentrations of glucose, insulin, IGF-I, progesterone, and estradiol in plasma were greater in nonlactating cows than in lactating cows. Lactating cows had fewer class 2 (6- to 9-mm) and class 3 (10- to 15-mm) follicles and more class 4 (> 15-mm) follicles than nonlactating cows. Bovine somatotropin increased the numbers of follicles in lactating cows so that the numbers of class 2 and of class 3 follicles were equivalent to those for non-lactating cows. Sizes of the largest follicles were similar for bST-and saline-treated cows. The second largest ovarian follicles, however, were larger in bST-treated cows. Ovarian follicular dynamics were altered by bST and lactation. Bovine somatotropin increased the numbers of follicles (6 to 15 mm) in lactating cows and size of second largest ovarian follicles in both lactating and nonlactating cows. Lactating cows developed dominant follicles that were larger and less estrogenic than those of nonlactating cows.

Animals↗

PubMed1993

Ovarian follicular populations in lactating dairy cows treated with recombinant bovine somatotropin (sometribove) or saline and fed diets differing in fat content and energy.

Interactions of dietary energy and fat with recombinant bST (sometribove) injections were tested for their effects on ovarian function. Lactating dairy cows were fed one of three diets differing in energy concentration (NEL) and percentage of DM of calcium salts of long-chain fatty acids: diet 1, 1.68 Mcal/kg and 0%; diet 2, 1.68 Mcal/kg and 2.2%; and diet 3, 1.78 Mcal/kg and 2.2%. Cows were injected daily with bST or saline during one of two 19-d interestrous periods (crossover design) in which ovarian follicles were measured by ultrasonography. The bST-treated cows produced more FCM and were in lower energy balance than saline-treated cows. Before d 12 (first follicular wave, estrus = d 0), bST-treated cows had more ovarian follicles in classes 1 (3 to 5 mm; cows on diet 3) or 2 (6 to 9 mm; cows on diets 1 and 2) than saline-treated cows. After d 12 (preovulatory follicular wave), numbers of follicles in different size classes were similar for bST-treated and saline-treated cows, but cows fed diet 2 had larger preovulatory follicles. Lower dietary energy and bST treatment were both associated with larger subordinate follicles. Ovarian follicles less than 10 mm were stimulated by bST, and calcium salts of long-chain fatty acids increased diameters of preovulatory follicles.

Animals↗

PubMed1992

Follicular dynamics, plasma metabolites, hormones and insulin-like growth factor I (IGF-I) in lactating cows with positive or negative energy balance during the preovulatory period.

The effect of dietary energy balance (EB) on growth of ovarian follicles was tested. Cows (n = 9) were fed a high energy diet (HE diet; positive EB; n = 4) or switched to a low energy diet (LE diet; negative EB; n = 5) during the preovulatory period. Non-esterified fatty acids (NEFA) were greater in cows fed the LE diet. Concentrations of luteinizing hormone (LH) were similar in HE and LE cows. However, the growth of preovulatory follicles in cows fed the LE diet was 50% that of cows fed the HE diet. Insulin-like growth factor-I (IGF-I) in plasma was less in LE-fed cows compared with HE-fed cows, and plasma IGF-I was positively correlated to estrogen: progesterone ratio in follicular fluid of dominant follicles. In summary, slower follicular growth in cows fed an LE diet occurred despite normal plasma LH and coincided with reduced IGF-I and elevated NEFA in plasma.

Animals↗

PubMed1992

Factors that affect ovarian follicular dynamics in cattle.

Studies of ovarian follicular dynamics in cattle may lead to methods for improving fertility, for synchronizing estrus with more precision, and for enhancing superovulatory responses. Within an estrous cycle, two or three large (> 10 mm) follicles develop during consecutive waves of follicular growth. The last wave provides the ovulatory follicle, whereas preceding wave(s) provide follicles that undergo atresia. The life span of large follicles seems to depend on the pulsatile secretion of LH; decreased frequency of LH pulses results in atresia of large follicles. Aromatase activity in the walls of the largest follicles is greatest during the first 8 d of the estrous cycle and decreases by d 12. Steroidogenesis of the largest and second-largest ovarian follicles differs on d 5, 8, and 12 of the estrous cycle. Follicular dynamics are altered by negative energy balance and lactation. The number of large follicles and concentration of estradiol during the preovulatory period differs between postpartum lactating and nonlactating cows. Dietary fats stimulate follicular growth when they are fed to increase energy balance. Administration of bovine somatotropin decreases energy balance and has a differential effect on ovarian follicular responses; growth of the largest follicle does not change, but growth of the second-largest follicle is stimulated by somatotropin. Studies of follicular dynamics in lactating cows demonstrate changes in ovarian function associated with energy balance that may be related to inefficient reproductive performance of cows producing high yields of milk.

Animals↗

PubMed1991

Follicular dynamics and superovulatory response in Holstein cows treated with FSH-P in different endocrine states.

The effect of follicular and/or endocrine environments on superovulatory response was tested. Eighteen nonlactating Holstein cows were superovulated with 32 mg FSH-P given in decreasing doses at 12-h intervals plus two injections of prostaglandin F2-alpha (25 mg each) on the third day of treatment. Cows were assigned randomly to treatments: T1, superovulatory treatment initiated on estrous cycle Day 10.5; T2, CIDR (intravaginal device containing 1.9 g of progesterone) inserted from Days 3 to 9 and superovulation initiated on Day 6.5; T3, identical to T2 but Buserelin (GnRH agonist) was injected (8 microg, i.m.) on Day 3 at the time of CIDR insertion. Embryos were recovered on Day 7 after the superovulatory estrus. Cows were examined daily by ultrasonography and blood was collected for progesterone and estradiol determinations. Mean diameter of the dominant follicle (frequency of first-wave dominant follicle) at the beginning of FSH injections was 13.7 mm (4/6), 11.2 mm (6/6) and 8.7 mm (6/6) (P<0.01) for T1, T2 and T3, respectively. Following initiation of superovulation, follicles moved into larger follicle classes (Class I, <3 mm; Class II, 3 to 4 mm; Class III, 5 to 9 mm; Class IV >9 mm) earliest in T1 (P<0.01). Cumulative follicular diameter and plasma concentrations of estradiol at Day 4 of superovulation were higher (P<0.01) in T1 (200 mm, 82 pg/ml) compared with T2 (123 mm, 24 pg/ml) and T3 (130 mm, 18 pg/ml). Proportion of cows in estrus prior to 12 h vs 12 to 24 h differed (P<0.05) between groups (T1: 5 vs 1; T2: 2 vs 4; T3: 1 vs 5). Mean number of follicles on the last day of superovulation treatment, number of CL and number of embryos plus unfertilized ova recovered were 17.5, 12.2 and 13.3; 13.8, 10 and 8.2 (P<0.1) and 8.7, 4.5 and 2.3 (P<0.05) for T1, T2 and T3, respectively. The developmental stage of the dominant follicle was associated with not only the number of ovulations, but also the size and periestrous concentrations of plasma estradiol associated with the recruited follicles.

Journal Article↗

PubMed1991

Energy balance and size and number of ovarian follicles detected by ultrasonography in early postpartum dairy cows.

Multiparous Holstein cows (n = 52) were fed one of six diets consisting of a totally mixed ration (corn silage, corn grain, soybean meal, dried distillers grains, and whole cottonseed) plus either alfalfa hay, alfalfa cubes, or bermuda-grass hay fed chopped as a component in the mixed ration or separate as long hay. Predicted energy balance was calculated from DM intake, milk yield and composition, and BW. On d 25 postpartum, ovarian status was programmed by injecting 25 mg of prostaglandin F2 alpha and treating cows for 15 d with an intravaginal device containing 1.9 g progesterone. Before d 25, number of class 1 follicles (3 to 5 mm; detected by ultrasonography) decreased with increasing days postpartum, and number of class 3 (10 to 15 mm) and class 4 (greater than 15 mm) follicles increased. The number of class 1 and 2 follicles (6 to 9 mm) decreased with increasing energy balance, and number of class 3 follicles increased with energy balance. Before d 25, predicted energy balance explained treatment differences in the number of follicles within each size class. After d 25, energy balance did not affect the average number of follicles per cow, but diet affected the number of follicles within each class. Predicted energy balance and dietary treatments influenced number of follicles at different times after calving. These results identify the importance of diet and energy balance to follicular and ovarian function in postpartum lactating dairy cows.

Animal Feed↗

PubMed1991

Effect of feeding calcium soaps to early postpartum dairy cows on plasma prostaglandin F2 alpha, luteinizing hormone, and follicular growth.

Multiparous Holstein cows (n = 18) were fed a total mixed ration containing corn silage, corn grain, whole cottonseed, soybean meal, dried distillers grains, and chopped bermudagrass hay (control) or same diet plus Ca salts of long-chain fatty acids (2.2% of diet DM) for the first 60 d postpartum. Predicted energy balance was calculated from DM intake, milk yield and composition, and BW. On d 25 postpartum, cows were injected with 25 mg of prostaglandin F2 alpha and treated for 15 d with an intravaginal device containing 1.9 g progesterone. Profiles of 15-keto-13,14-dihydro-prostaglandin F2 alpha (d 1 to 21) and plasma triglycerides (d 7 to 60) were similar between groups. Average number of follicles, determined by ultrasonography prior to d 25, tended to differ between groups; controls had more 3- to 5-mm and fewer 6- to 9-mm follicles than the group of fat-fed cows. Basal, smoothed mean concentration, and average luteinizing hormone amplitude, determined by 10-min samples for 8 h on d 10, were not significantly different between groups. Increasing predicted energy balance was associated with increased pulse amplitude and diameter of the largest follicle on d 10. During the progesterone treatment period and the postprogesterone treatment estrous cycle, cows fed fat had greater numbers of 3- to 5-mm and greater than 15-mm follicles. In conclusion, feeding fat did not influence 15-keto-13,14-dihydro-prostaglandin F2 alpha or luteinizing hormone dynamics but did alter the average number of follicles within different size classes and the diameter of largest and second largest follicle after progesterone treatment.

Animal Feed↗

PubMed1990

Ultrasonic identification of follicular populations and return to estrus in early postpartum dairy cows given intravaginal progesterone for 15 days.

In an attempt to program ovarian function in the early post partum period, 52 lactating Holstein cows were injected with 25 mg prostaglandin F(2 alpha) (PGF) and given a CIDR device containing 1.9 g progesterone for 15 d starting on Day 25 post partum. Ovarian follicles were measured by ultrasound on 0, 5, 10 and 15 d after insertion and on alternate days after CIDR removal until estrus. Not all cows were devoid of corpora lutea (CL) during the CIDR (11, 9 and 8 cows had a CL on Days 5, 10 and 15, respectively). There was a CL by day interaction (P<0.01) for the number of 10- to 15-mm follicles per cow; the average number of large follicles (>15 mm) was twice greater (0.75 vs 0.37) for those cows not having a CL during the period of CIDR exposure. The average size of the largest follicle increased to a maximum of 19.3 +/- 0.7 mm by 15 d after insertion in cows not having a CL. Plasma estradiol increased for 10 d after insertion, then decreased to the end of the CIDR period. After removal of the CIDR, 34 cows ovulated, eight cows developed ovarian follicular cysts, and eight cows did not ovulated by 14 d. Cows becoming cystic or not ovulating had a declining number of follicles during the CIDR compared with those cows ovulating (P<0.07). The diameter of the largest follicle in cystic cows was equivalent to noncystic cows until removal of the CIDR, but then it increased markedly. Interval to estrus was longer in cows having more 6- to 9-mm follicles on Day 15 (day of CIDR removal). These results demonstrate the existence and maintenance of a large dominant follicle after CIDR insertion and PGF injection which was influenced apparently by the presence of a CL. Furthermore, subsequent reproductive responses after the CIDR treatment was a function of follicular populations prior to withdrawal of the CIDR device. This system may be appropriate for the study of factors regulating follicular growth and fertility in domestic cattle.

Journal Article↗

PubMed1990

Effect of timing of prostaglandin PGF 2 alpha injection subsequent to embryo collection on the resumption of normal follicular development following superovulatory treatment in cattle.

Nonlactating Holstein and Jersey cows (n = 24) were superovulated and ovarian follicular development was monitored by transrectal ultrasound during the period after embryo recovery. Luteolysis was induced by two injections of prostaglandin F(2)alpha (PGF; 25 mg Lutalyse; 12-h interval) at specific times after superovulatory induced estrus (Treatment 1, Day 9; Treatment 2, Day 12; Treatment 3, Day 17; Treatment 4, Day 25; superovulatory estrus = Day 0 of Cycle 1). Follicular development was monitored during Cycle 1 before and after PGF injection and continued through the ensuing estrous cycle (Cycle 2). Superovulation led to more than one embryo collected in 14 cows (mean = 8.71 embryos: positive superovulatory response [PSR] cows), while 10 cows were not successfully superovulated (mean = 0.1 embryo; negative superovulatory response [NSR] cows). These cows differed in terms of number of unovulated follicles detected at embryo collection (4.21 vs 17.2, PSR vs NSR) and plasma progesterone during the superovulatory estrous cycle (32.3 ng/ml PSR vs 8.6 ng/ml NSR). Follicular development during Cycle 1 started sooner in NSR than in PSR cows (day by class by response P<0.03) and was initiated on Days 11 to 12 in NSR cows and on Days 19 to 20 in PSR cows. Interval to estrus after PGF averaged 6.3 d. Cows having short intervals to estrus had follicles at the time of PGF injection. Treatment influenced the length of Cycle 1, but it did not affect the interval to estrus after PGF, the length of Cycle 2, or follicular development during Cycle 2. The results indicate that 1) the timing of PGF injection after embryo collection does not influence subsequent follicular populations, 2) elongated estrous cycles and intervals to estrus after PGF in superovulated cattle are a function of decreased follicular activity, and 3) the presence of numerous corpora lutea and not the superovulatory treatment, per se, seem to attenuate follicular growth.

Journal Article↗

PubMed1988

Cytoplasmic effects on selection response for increased growth rate in mice.

To determine if cytoplasmic effects have contributed to long-term selection response for increased growth rate in mice, reciprocal cross matings were made between an unselected control line (ICR) and a line (M16) derived from ICR by long-term selection for high postweaning weight gain from 3 to 6 wk of age. Embryos were recovered 2 to 4 d following mating and transferred to pseudopregnant F1 (DBA/2NCrlBR X C57BL/6NCrlBR) females. Thus, all embryos developed in similar uterine and postnatal maternal environments. A total of 122 M16 X ICR and 123 ICR X M16 mice was produced, representing 19 litters from each cross. Litters were standardized at birth to five to seven pups. Litter weights at birth and 1 wk were recorded. Body weights at 2, 3, 4, 5 and 6 wk and weight gain from 3 to 6 wk were obtained. Weights of liver, kidneys, and sc and epididymal fat pads of males were obtained at 6 wk. Females were mated at 8 wk, and litter size at birth was recorded. Least-squares procedures were used to test for differences between reciprocal crosses for all traits. Body weight at 4 wk was higher (P less than .05) for mice with ICR cytoplasm. No other significant differences were detected. There was no evidence that cytoplasmic effects influenced direct or correlated responses to long-term selection for increased postweaning weight gain.

Animals↗

PubMed1987

Rhodamine 123 as a cytoplasmic stain for mammalian zygotes.

A mitochondrion-specific fluorescent dye, rhodamine 123, stains the cytoplasm of ova from mice, rabbits, sheep, cattle and pigs. Mouse zygotes stained with rhodamine 123 are often observed with areas of negative stain where the pronuclei are located. However, such areas of negative staining are not observed in zygotes from rabbits, sheep or cattle. In vitro viability of mouse zygotes stained with rhodamine 123 is high if observed with fluorescent microscopy for 5 min or less. Observation for more than 5 min results in a significant effect on embryo developmental potential in vitro.

Journal Article↗

PubMed1986

Gonadotropin-releasing hormone at estrus: luteinizing hormone, estradiol, and progesterone during the periestrual and postinsemination periods in dairy cattle.

Administering gonadotropin-releasing hormone (GnRH) improved conception rates in our previous studies. Our objective was to determine if the effect of GnRH was mediated through serum luteinizing hormone (LH) and/or by altered secretion of serum progesterone (P) and estradiol-17 beta (E) during the periestrual and post-insemination periods. Cattle were given either GnRH (n = 54) or saline (n = 55) at 72 h and inseminated artificially (AI) 80 h after the second of two injections of either prostaglandin F2 alpha or its analog, cloprostenol. Progesterone and E were measured in blood serum collected during 3 wk after AI (estrus) from 60 females. Blood was collected for LH determinations via indwelling jugular cannulae from 14 cows and 11 heifers. Collections were taken every 4 h from 32 to 108 h after the second PGF injection (PGF-2) (periestrual period) and at more frequent intervals during 240 min after administration of GnRH (n = 18) or saline (n = 7). Ten females had a spontaneous preovulatory LH surge before GnRH treatment (GnRH-spontaneous), whereas GnRH induced the preovulatory LH surge in six females. A spontaneous LH surge appeared to be initiated in two heifers at or near the time of GnRH treatment (spontaneous and/or induced). The remaining seven cows had spontaneous LH surges with no subsequent change in LH after saline treatment. Serum P during the 21 days after estrus was lower (p less than 0.05) in both pregnant and nonpregnant (open) cattle treated previously with GnRH compared with saline. Serum P during the first week after estrus was greater (p less than 0.01) and increased (p less than 0.05) more rapidly in saline controls and in GnRH-spontaneous cattle than in those exhibiting GnRH-induced or GnRH-spontaneous and/or-induced surges of LH. Conception rate of cattle receiving GnRH was higher (p = 0.06) than that of saline-treated controls. These data suggest that GnRH treatment at insemination initiated the preovulatory LH surge in some cattle, but serum P in both pregnant and open cows was compromised during the luteal phase after GnRH treatment. Improved fertility may be associated with delayed or slowly rising concentrations of serum progesterone after ovulation.

Animals↗

PubMed1986

Controlling first service and calving interval by prostaglandin F2 alpha, gonadotropin-releasing hormone, and timed insemination.

Our objective was to determine if calving intervals could be shortened and made less variable by using prostaglandin F2 alpha to control the occurrence of first services. Holstein cows (n = 348) were assigned at calving to four treatment groups. Control cows (n = 88) were inseminated at their first observed estrus after 40 d postpartum. Estrous cycles of the remaining cows were synchronized with prostaglandin F2 alpha to allow insemination (first services) 80 h after the second injection (n = 86), insemination at 80 h preceded by gonadotropin-releasing hormone at 72 h (n = 86), or insemination at 72 and 96 h (n = 88) after the second injection (51 to 57 d postpartum). By design, interval to first service was reduced to 57 d for treated cows (63 d for controls) and was less variable (12% of that for controls). Conception rate at first service was lower after timed inseminations than that of controls. Intervals to conception and subsequent calving were similar in all treated cows and controls. Of cows sampled, 23 of 176 (13%) failed to respond with luteolysis when progesterone in serum exceeded 1 ng/ml, and 26 of 176 (15%) had low concentrations of progesterone in serum and could not respond to prostaglandin F2 alpha. Poor response to timed inseminations may have occurred because only 72% of 176 cows sampled responded with luteolysis. When only cows observed in estrus were considered, conception rate approached that of controls (51%).(ABSTRACT TRUNCATED AT 250 WORDS)

Analysis of Variance↗