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Biomedical subjects

M A Crowe

Publications and source records attributed to M A Crowe.

At least 37 records · Page 2Linked to original sources
PubMed2000

Effect of exogenous LH pulses on the fate of the first dominant follicle in postpartum beef cows nursing calves.

Prolonged postpartum anoestrus in beef cows is due to failure of early dominant follicles to ovulate. It is hypothesized that this failure to ovulate is due to inadequate LH pulse frequency. The objective of this study was to determine whether administration of hourly LH pulses would cause the first dominant follicle to ovulate. In Expt 1, 16 cows received either saline (n = 8) or porcine LH (pLH; 50 micrograms h-1; n = 8) as hourly pulses for 3-5 days from the second day of dominance of the first dominant follicle (day 0). In Expt 2, 21 cows received either saline (n = 7), or 50 micrograms pLH (n = 7) or 100 micrograms pLH (n = 7) as hourly pulses for 3 days. Appropriate ovarian scanning and assays of blood samples were carried out. In Expt 1, the number of dominant follicles that underwent atresia was not affected by increasing the number of LH pulses, but the duration of dominance (days) of the first and second dominant follicles and maximum size (mm) of the second dominant follicle were increased (P < 0.05). Oestradiol concentrations were higher (P < 0.05) in cows given hourly pLH pulses (3.1 +/- 1.2 pg ml-1) compared with controls (1.2 +/- 0.2 pg ml-1). Four of eight treated cows had an anovulatory LH surge. The number of follicle waves to first ovulation was not different (P < 0.05) between control (4.6 +/- 0.9) and pLH treated cows (3.9 +/- 0.5). In Expt 2, four of seven cows given pulses of 100 micrograms pLH h-1 ovulated the first dominant follicle, and the interval from calving to first ovulation was decreased (P < 0.05). In the remaining three cows, the duration of dominance of the first dominant follicle was increased (P < 0.005), the maximum size of the first dominant follicle was greater (P < 0.05), and the interval (days) from the start of infusion to new wave emergence was greater (P < 0.05) compared with cows that failed to ovulate in either the 50 micrograms pLH h-1 or control treatments. In conclusion, hourly pulses of pLH from day 1 after dominance of the first dominant follicle in postpartum beef cows can either prolong dominance or induce it to ovulate. This finding supports the hypothesis that LH pulse frequency is a key determinant of the fate of the dominant follicle in the early postpartum period.

Analysis of Variance↗
PubMed1998

Resumption of follicular waves in beef cows is not associated with periparturient changes in follicle-stimulating hormone heterogeneity despite major changes in steroid and luteinizing hormone concentrations.

To test the hypothesis that emergence of follicle waves postpartum is associated with a change in circulating FSH isoform distribution, 10 Limousin-cross suckler cows were blood sampled daily from 5 wk prepartum until first ovulation postpartum for FSH, LH, estradiol (E2), and progesterone assay. Follicular growth was monitored daily by ultrasonography from Days 5 to 10 postpartum until first ovulation. Distributions of circulating FSH isoforms were characterized (n = 4 per group) by chromatofocusing at 1) 18-33 days prepartum, 2) 3-5 days prepartum, 3) the first postpartum FSH rise responsible for emergence of the first follicle wave, and 4) the FSH rise that stimulated the ovulatory follicle wave. The interval to detection of the first postpartum dominant follicle (DF) was 9.6 +/- 0.58 days. The number of DF before first ovulation was 2.1 +/- 0.18, and first ovulation occurred at 28.6 +/- 1.54 days postpartum. Serum E2 concentrations were higher (p = 0.0001) in cows during the 5-wk period prepartum (53.8 +/- 6.29 pg/ml) than in the postpartum period up to first ovulation (1.5 +/- 0.15 pg/ml). In late pregnancy, there was an absence of recurrent FSH rises and LH concentrations were decreased (p < 0.0001) compared with those in the postpartum period. The emergence of each follicle wave postpartum was preceded by a 2- to 4-day rise in FSH concentrations. The pattern of FSH isoform distribution did not differ (p > or = 0.75) between the pre- and postpartum periods.

Animals↗
PubMed1998

Acute hemorrhagic edema of infancy.

Acute hemorrhagic edema of infancy (AHEI), also called postinfectious cockade purpura, is a leukocytoclastic vasculitis that was first described in the United States by Snow in 1913. AHEI affects children between 4 and 24 months of age; the cutaneous finding, similar to those of Henoch-Schönlein purpura (HSP), are dramatic in both appearance and rapidity of onset. We present a toddler with AHEI and compare the epidemiology, histology, and clinical manifestations of this disorder and HSP.

Acute Disease↗
PubMed1998

Granular cell tumor of the toe.

A 33-year-old black woman with an unusual case of a solitary granular cell tumor (GCT) involving the toe is presented, as is a review of the literature. The clinical presentation, histopathologic appearance, differential diagnosis, and treatment of solitary granular cell tumors are discussed. GCTs are uncommon tumors and are thought to be of Schwann cell origin. These tumors usually present as reddish-brown to flesh-colored papules that are occasionally tender or pruritic. The surface is usually smooth, but may be ulcerated or verrucous. Although they are usually solitary, they may be multiple. These tumors are almost always benign, but malignant variants have been reported. Predilection is greatest in females, and blacks are affected several times more often than whites. The skin overlying the face, trunk, fingers, and mucous membranes account for the vast majority of reported cases.

Adult↗
PubMed1997

Validation of a sensitive radioimmunoassay to measure serum follicle-stimulating hormone in cattle: correlation with biological activity.

Meaningful biological interpretation of the role of follicle-stimulating hormone (FSH) requires use of a validated radioimmunoassay (RIA) that closely estimates biologically active FSH, which was the objective of this work. Three FSH antibodies [NIDDK anti ovine FSH (oFSH); JAD anti oFSH; USDA anti bFSH] were screened against three tracer preparations [USDA oFSH-19-SIAFP-I2(USDA oFSH I2); LER1976a oFSH; USDA bFSH I2] in a RIA using USDA bFSH B1 or I2 as the assay standard. Sera obtained from three heifers at 4- to 8-h intervals for 5 days after injection of PGF2 alpha during the luteal phase were assayed for both FSH immunoactivity using each of the three optimized assay formats (NIDDK anti oFSH and JAD anti oFSH with USDA oFSH I2 as tracer; USDA anti bFSH with USDA bFSH I2 as tracer), and FSH bioactivity, using a rat Sertoli cell bioassay. Cross reactivity of bLH (NIH bLH B9) in all three assay formats was minimal (0.7, 0.9 and < 0.4% at 50% binding for the NIDDK, JAD and USDA antibodies, respectively). There was parallel displacement of tracer between bovine serum dilutions of 10 to 500 microliters and the two FSH standards. Correlations between JAD and USDA RIA data and bioassay results were not significant (P > or = 0.10), but were significant (r = 0.78; P = 0.0001) for the NIDDK RIA FSH and the bioactive FSH measurements. The assay sensitivity of the NIDDK RIA was 0.55 ng USDA bFSH B1 (0.013 ng USDA bFSH I2)/ml. The inter- and intra-assay CV were between 5.8 and 7.9 %. This RIA detected a pre-ovulatory FSH surge coincident with the LH surge, in all heifers studied. Furthermore, the emergence of each wave of follicle growth (up to day 12 of the cycle), was preceded by a transient increase (P < 0.02; days 0.5 to 1.5 and 8 to 10.5 of the cycle) in serum FSH, while LH concentrations remained unchanged. In conclusion, the RIA utilising NIDDK anti oFSH and USDA oFSH I2 as tracer provides a good estimate of bioactive FSH in cattle, and detects physiologically relevant increases in serum FSH related to emergency of each new wave of follicle growth.

Animals↗
PubMed1997

Circulating FSH isoform patterns during recurrent increases in FSH throughout the oestrous cycle of heifers.

Blood samples were collected from heifers (n = 6; 450 +/- 7.7 kg) 2-4 times a day during the first and second follicular waves, and during the gonadotrophin surge to determine whether changes in circulating FSH isoforms occur during cyclic quantitative changes in FSH throughout the oestrous cycle. Serum was assayed for FSH, LH, oestradiol and progesterone. Selected samples collected during the first (samples 1-3) and second (samples 4-6) postovulatory recurrent FSH increase and during the subsequent gonadotrophin surge (samples 7 and 8) were analysed for FSH isoforms by chromatofocusing. No change (P > 0.05) in isoform profile occurred during the first or second recurrent FSH increase, when oestradiol concentrations were 0.6 +/- 0.07 and 0.6 +/- 0.09 pg ml-1 and progesterone concentrations were 0.03 +/- 0.01 and 2.4 +/- 0.19 ng ml-1, respectively. The percentage of FSH eluting in the pH range 7.4-7.0 increased (P < 0.05) from 14.2 +/- 2.2 during the luteal phase (samples 1-6) to 20.2 +/- 2.3 (sample 7) and 31.4 +/- 3.4% (sample 8) during the preovulatory gonadotrophin surge, while oestradiol concentrations were higher (P < 0.05; 4.9 +/- 0.39 pg ml-1) than in the luteal phase of the cycle. In summary, FSH isoform patterns did not change during the cyclic quantitative changes in FSH associated with emergence of the first or second follicular wave. However, during the gonadotrophin surge, in association with increased oestradiol concentrations, an increase in the amount of less acidic isoforms of FSH was observed. Therefore, qualitative changes in FSH are not important in the physiological regulation of follicle turnover during the luteal phase of the oestrous cycle of heifers.

Animals↗
PubMed1997

Effects of cortisol on in vitro interferon-gamma production, acute-phase proteins, growth, and feed intake in a calf castration model.

The objective of this study was to determine the effects of castration, with its presumed pain and inflammatory effects, including increased cortisol, and elevated cortisol per se on in vitro interferon-gamma (IFN-gamma) production, ADG, ADFI, and plasma haptoglobin and fibrinogen. Thirty Friesian bull calves (174 +/- 3.8 kg) were assigned to three treatments (given on d 0): 1) control (CON); 2) i.v. cortisol administration to mimic castration-induced increases in cortisol (CORT); and 3) surgical castration (SURG). Blood samples were collected for 12 h on d 0 and at 24 and 72 h after treatment for cortisol determination. Keyhole limpet hemocyanin (KLH)- and concanavalin A (Con A)-induced in vitro IFN-gamma production in blood, and plasma haptoglobin and fibrinogen were measured in blood samples taken before treatment on d 0 and on d 1 and 3. On d 0, CORT and SURG animals had higher peak cortisol (P < .001) and area under the cortisol curve (P < .001) than CON animals. There were no differences (P > .05) between CON, CORT, and SURG animals in cortisol at 24 and 72 h. There were no differences (P > .05) between CON and CORT animals in IFN-gamma production, haptoglobin, fibrinogen, ADG, and ADFI. Compared with CON animals, SURG animals had lower (P < .05) KLH-induced IFN-gamma on d 1 and CON A-induced IFN-gamma on d 1 and 3. Haptoglobin concentrations were greater (P < .05) for SURG than for CON animals on d 1 and 3. Fibrinogen concentrations were greater (P < .001) for SURG than for CON animals on d 3. The SURG animals had lower (P < .01) ADG and ADFI during d 0 to 7 than CON animals. In conclusion, castration decreased IFN-gamma production, ADG, and ADFI and increased haptoglobin and fibrinogen, and these effects seemed to be independent of plasma cortisol concentrations.

Acute-Phase Proteins↗
PubMed1997

Effects of suppressing cortisol following castration of bull calves on adrenocorticotropic hormone, in vitro interferon-gamma production, leukocytes, acute-phase proteins, growth, and feed intake.

The objective was to determine the effects of reducing the plasma cortisol rise in calves following castration on plasma ACTH concentrations, keyhole limpet hemocyanin (KLH)- and concanavalin A (Con A)-induced in vitro interferon (IFN)-gamma production, white blood cell (WBC) numbers, neutrophil:lymphocyte (N:L) ratio, plasma haptoglobin and fibrinogen concentrations, ADG, and ADFI. Forty 5-mo-old Friesian bull calves (169 +/- 1.7 kg) were assigned to four treatments: 1) control (CON); 2) oral metyrapone administration (MET); 3) surgical castration at 0 h on d 0 (SURG); and 4) oral metyrapone administration and surgical castration (MET+SURG). Cortisol, ACTH, IFN-gamma production, haptoglobin, fibrinogen, ADFI, and ADG were not different between CON and MET animals. The MET+SURG calves had lower (P < .001) peak and mean cortisol during .25 to 1.5 h than SURG animals, but area under the cortisol vs time curve from 0 to 12 h did not differ (P > .39) between SURG and MET+SURG calves. Peak ACTH concentrations and area under the ACTH vs time curve from 0 to 6 h were greater (P < .05) for MET+SURG than for SURG calves. There were no differences between MET+SURG and SURG animals in IFN-gamma production, WBC numbers, and ADFI. On d 1, MET+SURG and SURG animals had lower (P < .01) KLH- and Con A-induced IFN-gamma production and higher (P < .05) neutrophil numbers and N:L ratio compared with CON animals. Plasma haptoglobin on d 1 and 3 and fibrinogen concentrations on d 3 and 7 were elevated (P < .05) for MET+SURG and SURG compared with CON animals, whereas SURG animals had greater (P < .05) haptoglobin and fibrinogen concentrations than MET+SURG animals on d 7. The ADG of SURG calves was lower (P < .05) than that of MET+SURG calves during d 0 to 7. Metyrapone treatment partially suppressed cortisol and increased ACTH in castrated calves but did not alter the castration-induced suppression of IFN-gamma and increases in neutrophil numbers and the N:L ratio.

Acute-Phase Proteins↗
PubMed1996

Normal or induced secretory patterns of luteinising hormone and follicle-stimulating hormone in anoestrous gonadotrophin-releasing hormone-immunised and cyclic control heifers.

The objective was to determine the effect of gonadotrophin-releasing hormone (GnRH), GnRH analogue (GnRH-A) or oestradiol administration on luteinising hormone (LH) and follicle-stimulating hormone (FSH) release in GnRH-immunised anoestrous and control cyclic heifers. Thirty-two heifers (477 +/- 7.1 kg) were immunised against either human serum albumin (HSA; controls; n = 8), or a HSA-GnRH conjugate. On day 70 after primary immunisation, control heifers (n = 4 per treatment; day 3 of cycle) received either (a) 2.5 micrograms GnRH or (b) 2.5 micrograms of GnRH-A (Buserelin) and GnRH-immunised heifers (blocked by GnRH antibody titre; n = 6 per treatment) received either (c) saline, (d) 2.5 micrograms GnRH, (e) 25 micrograms GnRH or (f) 2.5 micrograms GnRH-A, intravenously. On day 105, 1 mg oestradiol was injected (intramuscularly) into control (n = 6) and GnRH-immunised anoestrous heifers with either low (13.4 +/- 1.9% binding at 1:640; n = 6) or high GnRH antibody titres (33.4 +/- 4.8% binding; n = 6). Data were analysed by ANOVA. Mean plasma LH and FSH concentrations on day 69 were higher (P < 0.05) in control than in GnRH-immunised heifers (3.1 +/- 0.16 vs. 2.5 +/- 0.12 ng LH ml-1 and 22.5 +/- 0.73 vs. 17.1 +/- 0.64 ng FSH ml-1, respectively). The number of LH pulses was higher (P < 0.05) in control than in GnRH-immunised heifers on day 69 (3.4 +/- 0.45 and 1.0 +/- 0.26 pulses per 6 h, respectively). On day 70, 2.5 micrograms GnRH increased (P < 0.05) LH concentrations in control but not in GnRH-immunised heifers, while both 25 micrograms GnRH and 2.5 micrograms GnRH-A increased (P < 0.05) LH concentrations in GnRH-immunised heifers, and 2.5 micrograms GnRH-A increased LH in controls. FSH was increased (P < 0.05) in GnRH-immunised heifers following 25 micrograms GnRH and 2.5 micrograms GnRH-A. Oestradiol challenge increased (P < 0.05) LH concentrations during the 13-24 h period after challenge with a greater (P < 0.05) increase in control than in GnRH-immunised heifers. FSH concentrations were decreased (P < 0.05) for at least 30 h after oestradiol challenge. In conclusion, GnRH immunisation decreased LH pulsatility and mean LH and FSH concentrations. GnRH antibodies neutralised low doses of GnRH (2.5 micrograms), but not high doses of GnRH (25 micrograms) and GnRH-A (2.5 micrograms). GnRH immunisation decreased the rise in LH concentrations following oestradiol challenge.

Anestrus↗
PubMed1996

Effect of castration method and the provision of local anesthesia on plasma cortisol, scrotal circumference, growth, and feed intake of bull calves.

To determine the effects of castration of calves, with or without local anesthesia, on plasma cortisol, scrotal circumference, ADG, and ADFI, 56 Friesian bulls (5.5 mo of age; mean +/- SE BW = 173 +/- 2 kg) were randomly assigned to each of seven treatments: 1) control (CON); 2) s.c. injection of .1 mg of a human serum albumin-GnRH conjugate with DEAE-dextran adjuvant (HSA-GnRH); 3) burdizzo castration without local anesthetic (BURD); 4) burdizzo castration following local anesthetic administration (BURD + LA); 5) surgical castration without local anesthetic (SURG); 6) surgical castration following local anesthetic administration (SURG + LA); and 7) local anesthetic administration alone (LAA). Blood samples for cortisol analyses were taken via jugular catheter from -2 to 10 h and at 24, 48, and 72 h relative to treatment. Average daily feed intakes were recorded for 5-d periods and calves weighed at 7-d intervals before and after treatment. Local anesthetic alone had no effect (P > .10) on any variable. The HSA-GnRH calves had elevated (P < .05) plasma cortisol from 2 to 6 h compared with CON calves. Peak plasma cortisol was elevated (P < .01) in BURD, BURD + LA, SURG, and SURG + LA compared with CON calves. The SURG calves (46.0 ng/mL) had higher (P < .03) peak cortisol than BURD (31.4 ng/mL) and SURG + LA (35.4 ng/mL) calves. There was no difference in peak cortisol between BURD and BURD + LA (26.5 ng/mL) calves. The ADG from d 0 to 7 was reduced (P < .05) in calves in BURD + LA, SURG, and SURG + LA treatments (-.01, -.83 and -.24 kg, respectively) compared with CON calves (.54 kg). The ADFI were reduced (P < .05) in BURD and BURD + LA calves during d 1 to 5 and in BURD + LA, SURG, and SURG + LA calves during d 6 to 10 compared with CON calves. The scrotal circumferences of BURD and BURD + LA calves were greater (P < .05) than those of CON calves for 7- and 35-d periods post-castration, respectively. Castration induced increases in cortisol and decreases in ADG and ADFI. Surgical castration induced a greater plasma cortisol response than burdizzo castration, and the administration of local anesthetic reduced the cortisol response of surgical castrates but was less effective for burdizzo castrates.

Anesthesia, Local↗
PubMed1995

Immunization of prepubertal beef heifers against gonadotropin-releasing hormone: immune, estrus, ovarian, and growth responses.

To develop an effective immunization protocol against human serum albumin-Cys-Gly-GnRH (HSA-GnRH) conjugate to delay the onset of puberty in heifers, 58 heifers (8 mo of age; mean +/- SE BW = 203 +/- 1 kg) were randomly assigned to each of six treatments: 1) controls, .1 mg of HSA, with diethylaminoethyl (DEAE)-dextran as adjuvant, on d 0 and 28; 2) .1 mg of HSA-GnRH, with DEAE-dextran, on d 0; 3) as 2) and booster on d 28; 4) as 3) but boosters also on d 84, 140, 196, and 252; 5) as 2) but half the conjugate given with DEAE-dextran adjuvant and half with non-ulcerative Freund's adjuvant (NUFA), injected in two separate sites; and 6) as 2) but the conjugate given with DEAE-dextran and NUFA, emulsified and injected in two sites. The duration of the experiment was 342 d. Mean plasma GnRH antibody titers (samples every 2 wk) for heifers in Treatments 2 to 6 were 9.4 +/- 1.16, 20.6 +/- 2.21, 43.9 +/- 2.86, 27.9 +/- 2.67, and 44.5 +/- 3.75% binding at a plasma dilution of 1:640. The mean number of times estrus was observed in heifers was less (P < .05; pooled SEM = .53) in Treatments 4 (.2) and 6 (2.4) than in Treatments 1, 2, 3, and 5 (7.8, 7.0, 7.0, and 6.6, respectively). The mean interval to the onset of puberty (the first increase in plasma progesterone > or = .5 ng/mL for > or = 10 d with samples at 3- to 4-d intervals) was greater (P < .05; pooled SEM = 11.6) for heifers in treatments 4 (339 d) and 6 (276 d) than for heifers in Treatments 1, 2, 3, and 5 (164, 159, 165, and 170 d, respectively). Mean ADG of heifers was reduced (P < .05) in treatments 2, 3, 4, and 6 (.71, .72, .68, and .69 kg, respectively) compared with controls (.77). In summary, the multiple booster immunization treatment induced and maintained sufficient anti-GnRH titer to delay puberty for 175 d; a single immunization against GnRH with DEAE and NUFA increased antibody titers enough to delay puberty for 112 d. However, GnRH immunization treatments reduced ADG of heifers in Treatments 2, 3, 4, and 6.

Aging↗
PubMed1995

Growth and estrous behavior of heifers actively immunized against prostaglandin F2 alpha.

To determine the effects of active immunization against prostaglandin F2 alpha (PGF) on estrous activity and performance traits of beef heifers, 50 14-mo-old cyclic heifers (358 +/- 3.3 kg) were assigned to two treatments (n = 25 per treatment): 1) heifers (controls) given 3.3 mg of human serum albumin (HSA) on d 0 (primary) and 27 (booster), and 2) heifers (PGF-immunized) given 3.3 mg of PGF-HSA on d 0 and 27. The adjuvant was DEAE-dextran, and the duration of the experiment was 167 d. Plasma progesterone concentrations (every 3 to 4 d) were used to monitor corpus luteum (CL) presence; PGF antibody titers were determined every 2 wk. Heifers were checked twice daily for estrous behavior and were weighed every 2 wk. Data were analyzed using ANOVA. Antibody titers for PGF-immunized heifers increased to a peak (43 +/- 2.9% binding at a plasma dilution of 1:1,250) on d 55 +/- 4.6. Antibody titers were greater (P = .02) in PGF-immunized than in control heifers by d 15 and remained elevated (P < or = .001) throughout the experiment. Twenty-four of 25 PGF-immunized heifers formed persistent CL with a mean duration of 129 +/- 6.4 d. The mean number of estrous period per heifer were less for PGF-immunized (1.5 +/- .27) than for control heifers (7.0 +/- .32). Mean daily live weight gain of the PGF-immunized heifers was decreased (P < .05; .75 +/- .024 kg) compared with that of controls (.83 +/- .014 kg), largely due to a 31.5% decrease during the 28-d period after booster.(ABSTRACT TRUNCATED AT 250 WORDS)

Analysis of Variance↗
PubMed1995

Immunization of heifers against gonadotropin-releasing hormone: antibody titers, ovarian function, body growth, and carcass characteristics.

To investigate the effects of active immunization of cyclic beef heifers with different doses of a human serum albumin-Cys-Gly-GnRH (HSA-GnRH) conjugate on antibody titers, ovarian function, body growth, and carcass characteristics, 32 heifers (BW = 477 +/- 7.1 kg; mean +/- SE) were assigned to one of four immunization treatments: .1 mg of HSA or .01, .1, or 1.0 mg of HSA-GnRH, respectively. All heifers received a primary (d 0) and booster (d 28) immunization using DEAE-dextran as adjuvant. The duration of the experiment was 158 d. Overall antibody titers against GnRH were greater (P < .05) for heifers immunized against GnRH (13 +/- 3.3, 22 +/- 3.8, and 19 +/- 2.8% binding at a plasma dilution of 1: 640 for Treatments 2 to 4, respectively) than for controls (1 +/- .1%). The numbers of heifers that became anestrous (plasma progesterone < .5 ng/mL for > 21 d) were 1/8, 8/8, 7/8, and 8/8, respectively. The interval from primary immunization to anestrus (40.7 +/- 6 d) and the duration of anestrus (78 +/- 7 d) were not affected by dose of HSA-GnRH conjugate. The number of ovulations detected was reduced (P < .05) in GnRH-immunized (4.6 +/- .64, 4.0 +/- .70, and 3.6 +/- .60 for Treatments 2 to 4, respectively) compared with control heifers (9.4 +/- .20). During induced anestrus, follicular growth was generally arrested (< 5 mm in diameter) and plasma estradiol decreased.(ABSTRACT TRUNCATED AT 250 WORDS)

Adjuvants, Immunologic↗
PubMed1995

Effects of single or primary plus booster prostaglandin F2 alpha immunization regimens on immune, ovarian, and growth responses of heifers.

Growth rate of heifers is reduced by prostaglandin F2 alpha (PGF) immunization following a primary and booster regimen. The objective was to attenuate the immune response with or without a booster immunization; specifically, the effects of booster interval, dose of PGF-human serum albumin (HSA) conjugate at booster, adjuvant type, or single immunization with one or two adjuvants were examined. Three experiments were conducted using 175 cyclic heifers. Plasma PGF antibody titers were measured every 2 wk and progesterone concentrations every 3 to 4 d. In Exp. 1, single immunization with one adjuvant (3.3 mg of PGF-HSA in either DEAE-dextran [DEAE] or non-ulcerative Freund's adjuvant [NUFA]; or 10.0 mg of PGF-HSA in NUFA) did not induce sufficient antibody titers to consistently induce persistent corpora lutea (CL). Booster intervals of either 14, 21, or 28 d increased titers sufficiently to induce persistent CL (34/35 heifers), but ADG of heifers was less (P < .05) than for those given a single immunization. In Exp. 2, 1.0 mg of conjugate for booster immunization induced a greater (P < .05) immune response than 3.3 mg, and both doses decreased (P < .05) ADG. Single immunization, with half the conjugate dose in DEAE and half in NUFA injected separately, induced persistent CL in 7/8 heifers without decreasing ADG compared with controls. In Exp. 3, single immunization, with half the conjugate dose in DEAE and half in NUFA injected separately, prolonged (P < .05) the intervals to peak titer compared with the booster treatment, but the incidence (13/15 vs 8/8) and duration (120 +/- 4.8 vs 111 +/- 7.9 d) of persistent CL were similar, and ADG was greater (P < .05). In conclusion, attempts to attenuate the immune response following booster immunization were unsuccessful. Single immunization, using two adjuvants separately, induced persistent CL for at least 120 d without decreasing ADG compared with the primary and booster regimen.

Animals↗
PubMed1994

Prostaglandin F2 alpha immunization of prepubertal beef heifers: effects of conjugate dose and timing of immunization relative to puberty on the onset of puberty and subsequent ovarian function.

Fifty-six prepubertal Hereford cross Friesian heifers were assigned to seven treatment groups: (1) primary (day 0) and booster (day 41) using 10 mg human serum albumin (HSA) (control); (2) primary and booster (day 41) immunizations using 3.3 mg prostaglandin F2 alpha PGF-HSA conjugate; (3) primary and booster (day 83) using 3.3 mg PGF-HSA; (4) primary and booster (day 210) using 3.3 mg PGF-HSA; (5-7) as in treatments 2-4 except 10 mg PGF-HSA were used. Plasma progesterone concentrations were used to determine the onset of puberty and the presence of a corpus luteum (CL); plasma PGF antibody titres were determined at 28-day intervals. There was no effect (P > 0.05) of conjugate dose or booster interval on mean antibody titres and there was no interaction between them. However, heifers in the 83- and 210-day booster treatments had higher (P < 0.05) peak antibody titres than heifers in the 42-day booster treatments. Puberty was delayed in 40% (16/40) of PGF-immunized heifers and 40% (16/40) of heifers formed persistent CL after puberty. Overall, eight of the heifers with delayed puberty also formed a persistent CL. There was a positive correlation between mean titre and onset of puberty but not with duration of persistent CL.

Animals↗
PubMed1994

Selection, dominance and atresia of follicles during the oestrous cycle of heifers.

This study examined the correlation between measurement of follicle growth by ultrasound, and measurement of intrafollicular ratios of oestradiol and progesterone concentrations and the serum concentrations of FSH during selection, dominance and atresia or ovulation of dominant follicles in heifers. Heifers were ovariectomized on days 0 (before LH surge), 1 (after LH surge, preovulation), 1 (postovulation), 3, 6 and 12 of the oestrous cycle. Blood samples were collected at 4-6 h intervals. After ovariectomy all follicles > or = 5 mm were measured and follicular fluid was aspirated. Follicles were classified by size according to ultrasound (F1, largest; F2, second largest; F3, all remaining follicles > or = 5 mm) and by the ratio of oestradiol:progesterone concentrations. During the follicular phase, a single dominant oestrogen-active follicle increased in diameter while serum concentrations of LH increased and FSH decreased (P < 0.05). On day 1 (after LH surge, preovulation), serum LH and FSH decreased to pre-surge concentrations (P < 0.0001), while follicle size and intrafollicular progesterone concentration increased and oestradiol concentration decreased (P < 0.05). A dominant nonovulatory follicle, classified as oestrogen-active on days 1, 3 and 6 and oestrogen-inactive on day 12, increased in size from day 1 to day 7 and lost dominance during days 10-12, coincident with the growth of multiple oestrogen-active follicles. The serum FSH concentration increased transiently (P < 0.05) before each new wave of dominant follicular growth. The overall correlation of ultrasound measurements of follicle diameter with measures of follicle size after ovariectomy was high.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1994

Active immunization against prostaglandin F2 alpha: effect of conjugate dose and booster interval on antibody titers and estrous behavior in postpubertal beef heifers.

To optimize the prostaglandin F2 alpha (PGF) immunization protocol (conjugate [PGF-human serum albumin; PGF-HSA] dose and immunization regimen) to achieve prolonged suppression of estrous behavior (EB) in beef heifers, 56, 14-mo-old cyclic heifers were assigned (n = 7 per treatment) to eight treatments: 1) 3.3 mg of PGF-HSA on d 0 (single); 2) 3.3 mg of PGF-HSA on d 0 and 28 (booster; B); 3) as (2) except on d 0 and 55; 4) as (2) except on d 0 and 83; and 5 to 8) as in Treatments 1 to 4 except using 10 mg of PGF-HSA. The adjuvant was diethylaminoethyl-dextran, and duration of the experiment was 170 d. Heifers were checked twice daily for EB. A persistent corpus luteum (CL) was considered present when progesterone (P4) was > or = .5 ng/mL for > or = six consecutive samples (every 3 to 4 d). Data were analyzed using ANOVA for a factorial plan. All heifers produced plasma antibody titers (samples every 2 wk) against PGF (peak range: 7 to 84% binding at 1: 1,250). There were no effects (P > .10) of conjugate dose and no interactions between dose and immunization regimen for any variable; therefore, data were combined across dose. Mean and peak titers were greater (P < .05) in heifers in 55- and 83-d B treatments than those in single immunization and 28-d B treatments. Overall, 48/55 heifers formed a persistent CL (41/41 for B heifers). In the single, and 55- and 83-d B treatments, 23/42 heifers formed persistent CL in response to single/primary immunization. There was no difference between immunization regimens in duration (133 +/- 4.4 d) of persistent CL.(ABSTRACT TRUNCATED AT 250 WORDS)

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