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M C Wiltbank - One of the best experts on this subject based on the ideXlab platform.
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Ovulation rate antral follicle count and circulating anti mullerian hormone in trio allele carriers a novel high fecundity bovine genotype
Theriogenology, 2017Co-Authors: A Garciaguerra, Jessica Cristina Lemos Motta, L F Melo, B W Kirkpatrick, M C WiltbankAbstract:High fecundity genotypes in sheep are a valuable model to study the physiological mechanisms underlying follicle selection and the control of Ovulation rate. Similar genotypes in cattle had not been described until the recent identification of a major bovine allele, termed Trio, which had a large effect on Ovulation rate. The present study was designed to evaluate Ovulation rate, antral follicle count (AFC), circulating ant-mullerian hormone (AMH), and the association among these measures in unstimulated and superstimulated Trio carrier cattle. We hypothesized that AFC and AMH would be variable among individual cows but would be similar between Trio carriers and non-carrier control cows and that there would be no association between these measures of follicle numbers and Ovulation rate. In experiment 1, Ovulation rate was determined during 4 consecutive estrous cycles in Trio carriers (n = 34) and non-carrier controls (n = 27). Ovulation rate, on average, was greater (P 0.70, respectively). In Experiment 3, circulating AMH was also not different between genotypes (P = 0.65) while correlations were found between AFC and AMH in Trio carriers (r = 0.43; P = 0.05; n = 27) and non-carrier controls (r = 0.78; P < 0.01; n = 19). In experiment 4, AFC and AMH were determined in Trio-carriers (n = 9) in relation to a synchronized follicular wave which was unstimulated or stimulated with exogenous FSH. Stimulation with FSH increased Ovulation rate, compared to unstimulated Trio carriers, however no association was found between AFC or AMH and Ovulation rate regardless of whether superstimulation with exogenous FSH was used. In conclusion, the novel high fecundity bovine genotype Trio, results in consistent multiple Ovulations despite having similar AFC and AMH. Therefore, our results suggest that differences in antral follicle numbers during the final stages of follicle development are not a key component of the mechanism underlying multiple Ovulations in Trio carriers.
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relationship between level of milk production and multiple Ovulations in lactating dairy cows
Journal of Dairy Science, 2005Co-Authors: H Lopez, D Z Caraviello, L D Satter, P M Fricke, M C WiltbankAbstract:Abstract Our objective was to evaluate factors associated with spontaneous multiple Ovulations in lactating dairy cows. Ovaries of cows [n=267; >50 days in milk (DIM)] were evaluated weekly using ultrasound to determine spontaneous (i.e., no hormonal treatment) Ovulation rate starting at 50 DIM and continuing until pregnancy diagnosis. Cows were fitted with a transmitter to record standing activity during estrus, and serum progesterone concentration was assessed weekly starting at wk 1 postpartum for all cows. Overall, 76 (28.5%) cows were anovular and 191 (71.5%) were ovular by 71 DIM. Incidence of anOvulation was not associated with level of milk production but was associated with lower body condition. For anovular cows (n=41) that spontaneously recovered, the multiple Ovulation rate at first Ovulation was 46.3%. For second and subsequent Ovulations (n=463), the level of milk production for 14 d preceding estrus was associated with increased Ovulation rate. To illustrate, incidence of multiple Ovulations was 1.6% (2/128), 16.9% (32/189), and 47.9% (70/146) for Ovulations when cows were producing 3 ). Similarly, serum progesterone concentration 7 d after estrus was lower for cows with multiple than single Ovulations (2.5±0.3 vs. 3.2±0.1 ng/mL) despite a greater luteal volume (8291±516 vs. 6405±158mm 3 ). In summary, the first spontaneous Ovulation in anovular cows and a higher level of milk production for 14 d preceding estrus were associated with increased multiple Ovulation rate. Additionally, cows with multiple Ovulations had lower estradiol at estrus, a shorter duration of estrus, and lower progesterone at 7 d after estrus than cows with single Ovulations.
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relationship between level of milk production and multiple Ovulations in lactating dairy cows
Journal of Dairy Science, 2005Co-Authors: H Lopez, D Z Caraviello, L D Satter, P M Fricke, M C WiltbankAbstract:Our objective was to evaluate factors associated with spontaneous multiple Ovulations in lactating dairy cows. Ovaries of cows [n = 267; >50 days in milk (DIM)] were evaluated weekly using ultrasound to determine spontaneous (i.e., no hormonal treatment) Ovulation rate starting at 50 DIM and continuing until pregnancy diagnosis. Cows were fitted with a transmitter to record standing activity during estrus, and serum progesterone concentration was assessed weekly starting at wk 1 postpartum for all cows. Overall, 76 (28.5%) cows were anovular and 191 (71.5%) were ovular by 71 DIM. Incidence of anOvulation was not associated with level of milk production but was associated with lower body condition. For anovular cows (n = 41) that spontaneously recovered, the multiple Ovulation rate at first Ovulation was 46.3%. For second and subsequent Ovulations (n = 463), the level of milk production for 14 d preceding estrus was associated with increased Ovulation rate. To illustrate, incidence of multiple Ovulations was 1.6% (2/128), 16.9% (32/189), and 47.9% (70/146) for Ovulations when cows were producing or=45 kg/d, respectively. Among cows for which estrous behavior was recorded, those with multiple Ovulations (n = 48) had shorter duration of estrus (4.3 +/- 0.7 vs. 9.9 +/- 0.5 h) and higher production (47.2 +/- 0.9 vs. 38.1 +/- 0.5 kg/d) than cows with single Ovulations (n = 237). Circulating concentrations of estradiol were lower (5.5 +/- 0.3; n = 15 vs. 7.8 +/- 0.4 pg/mL; n = 71) during periods of estrus with multiple Ovulations despite a greater preovulatory follicular volume (4136 +/- 123 vs. 3085 +/- 110 mm(3)). Similarly, serum progesterone concentration 7 d after estrus was lower for cows with multiple than single Ovulations (2.5 +/- 0.3 vs. 3.2 +/- 0.1 ng/mL) despite a greater luteal volume (8291 +/- 516 vs. 6405 +/- 158 mm(3)). In summary, the first spontaneous Ovulation in anovular cows and a higher level of milk production for 14 d preceding estrus were associated with increased multiple Ovulation rate. Additionally, cows with multiple Ovulations had lower estradiol at estrus, a shorter duration of estrus, and lower progesterone at 7 d after estrus than cows with single Ovulations.
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comparison of ovarian function and circulating steroids in estrous cycles of holstein heifers and lactating cows
Journal of Dairy Science, 2004Co-Authors: R Sartori, James M Haughian, R D Shaver, Guilherme J M Rosa, M C WiltbankAbstract:Abstract Ovarian function was compared between nulliparous heifers (n=29; 10 to 16 mo old) and lactating Holstein cows (n=31; 55.9±3.5 d postpartum). Follicular dynamics, corpus luteum growth, and regression, and serum steroid concentrations were evaluated through ultrasonography and daily blood sampling. Most heifers (27 of 29) but only 14 of 31 cows had typical spontaneous estrous cycles after cycles were initiated. Twelve cows had atypical cycles, and 5 became anovulatory during the study. The 12 cows with atypical estrous cycles had low serum estradiol after luteolysis and failed to ovulate the dominant follicle present at luteolysis. Heifers and cows with typical cycles were compared directly. Interovulatory intervals were similar between heifers (22.0±0.4 d) and cows (22.9±0.7 d). Those animals had estrous cycles with either 2 (15 heifers; 11 cows), 3 (9 heifers; 2 cows), or 4 follicular waves (3 heifers; 1 cow). Cows ovulated later after luteolysis than heifers (5.2±0.2 vs. 4.6±0.1 d, respectively), and had more multiple Ovulations (17.9 vs. 1.9%). Maximal serum estradiol concentration preceding Ovulation was lower in cows than in heifers (7.9±0.8 vs. 11.3±0.6 pg/mL) even though ovulatory follicles were larger in cows (16.8±0.5 vs. 14.9±0.2mm). Similarly, maximal serum progesterone concentration was lower for cows (5.6±0.5 vs. 7.3±0.4 ng/mL), whereas maximal volume of luteal tissue was larger for cows than heifers (11,120±678 vs. 7303±308mm 3 ). Thus, higher incidence of reproductive anomalies in lactating cows, such as low conception rate, Ovulation failure, delayed Ovulation, and multiple Ovulations, may be due to lower circulating steroid concentrations in spite of larger ovulatory follicles and luteal structures.
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ovarian structures and circulating steroids in heifers and lactating cows in summer and lactating and dry cows in winter
Journal of Dairy Science, 2002Co-Authors: R Sartori, Guilherme J M Rosa, M C WiltbankAbstract:Abstract Two experiments compared follicular and luteal development and circulating steroid concentrations from induced luteolysis to Ovulation in lactating Holstein cows (n=27; 40.0±1.5kg milk/day) vs. nulliparous heifers (n=28; 11 to 17 mo-old) during summer (Experiment 1), and in lactating (n=27; 45.9±1.4kg milk/d) vs. dry cows (n=26) during winter (experiment 2). All females received PGF 2α 6 d after Ovulation and were monitored until next Ovulation by daily ultrasound and assay of serum progesterone (P 4 ) and estradiol (E 2 ). Every female was used two or three times. In Experiment 1, lactating cows had high incidence of multiple Ovulation (63.5%) compared with heifers (1.3%). Among single ovulators, there was no difference in maximal size of ovulatory follicles between lactating cows and heifers (15.8 vs. 16.5mm, respectively). However, lactating cows had lower peak serum E 2 (8.6 vs. 12.1pg/ml), took longer to ovulate after luteolysis (4.6 vs. 3.8 d), developed more luteal tissue volume (7293.6 vs. 5515.2mm 3 ), and had lower serum P 4 on d 6 after Ovulation (2.0 vs. 3.0ng/ml) than heifers (data included multiple ovulators). In experiment 2, multiple Ovulations were similar between lactating and dry cows (17.9 vs. 17.2%, respectively). Peak serum E 2 was also similar between lactating and dry cows (7.6 vs. 8.5pg/ml) although lactating cows had larger ovulatory follicles (18.6 vs. 16.2±0.4mm). Lactating cows took longer to ovulate (4.8 vs. 4.2 d), developed more luteal tissue (7599 vs. 5139±468mm 3 ), but had similar serum P 4 (2.2 vs. 1.9ng/ml) compared with dry cows. Therefore, lactating cows had similar or lower circulating steroid concentrations than dry cows or heifers, respectively, despite having larger ovarian structures.
L D Satter - One of the best experts on this subject based on the ideXlab platform.
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relationship between level of milk production and multiple Ovulations in lactating dairy cows
Journal of Dairy Science, 2005Co-Authors: H Lopez, D Z Caraviello, L D Satter, P M Fricke, M C WiltbankAbstract:Abstract Our objective was to evaluate factors associated with spontaneous multiple Ovulations in lactating dairy cows. Ovaries of cows [n=267; >50 days in milk (DIM)] were evaluated weekly using ultrasound to determine spontaneous (i.e., no hormonal treatment) Ovulation rate starting at 50 DIM and continuing until pregnancy diagnosis. Cows were fitted with a transmitter to record standing activity during estrus, and serum progesterone concentration was assessed weekly starting at wk 1 postpartum for all cows. Overall, 76 (28.5%) cows were anovular and 191 (71.5%) were ovular by 71 DIM. Incidence of anOvulation was not associated with level of milk production but was associated with lower body condition. For anovular cows (n=41) that spontaneously recovered, the multiple Ovulation rate at first Ovulation was 46.3%. For second and subsequent Ovulations (n=463), the level of milk production for 14 d preceding estrus was associated with increased Ovulation rate. To illustrate, incidence of multiple Ovulations was 1.6% (2/128), 16.9% (32/189), and 47.9% (70/146) for Ovulations when cows were producing 3 ). Similarly, serum progesterone concentration 7 d after estrus was lower for cows with multiple than single Ovulations (2.5±0.3 vs. 3.2±0.1 ng/mL) despite a greater luteal volume (8291±516 vs. 6405±158mm 3 ). In summary, the first spontaneous Ovulation in anovular cows and a higher level of milk production for 14 d preceding estrus were associated with increased multiple Ovulation rate. Additionally, cows with multiple Ovulations had lower estradiol at estrus, a shorter duration of estrus, and lower progesterone at 7 d after estrus than cows with single Ovulations.
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relationship between level of milk production and multiple Ovulations in lactating dairy cows
Journal of Dairy Science, 2005Co-Authors: H Lopez, D Z Caraviello, L D Satter, P M Fricke, M C WiltbankAbstract:Our objective was to evaluate factors associated with spontaneous multiple Ovulations in lactating dairy cows. Ovaries of cows [n = 267; >50 days in milk (DIM)] were evaluated weekly using ultrasound to determine spontaneous (i.e., no hormonal treatment) Ovulation rate starting at 50 DIM and continuing until pregnancy diagnosis. Cows were fitted with a transmitter to record standing activity during estrus, and serum progesterone concentration was assessed weekly starting at wk 1 postpartum for all cows. Overall, 76 (28.5%) cows were anovular and 191 (71.5%) were ovular by 71 DIM. Incidence of anOvulation was not associated with level of milk production but was associated with lower body condition. For anovular cows (n = 41) that spontaneously recovered, the multiple Ovulation rate at first Ovulation was 46.3%. For second and subsequent Ovulations (n = 463), the level of milk production for 14 d preceding estrus was associated with increased Ovulation rate. To illustrate, incidence of multiple Ovulations was 1.6% (2/128), 16.9% (32/189), and 47.9% (70/146) for Ovulations when cows were producing or=45 kg/d, respectively. Among cows for which estrous behavior was recorded, those with multiple Ovulations (n = 48) had shorter duration of estrus (4.3 +/- 0.7 vs. 9.9 +/- 0.5 h) and higher production (47.2 +/- 0.9 vs. 38.1 +/- 0.5 kg/d) than cows with single Ovulations (n = 237). Circulating concentrations of estradiol were lower (5.5 +/- 0.3; n = 15 vs. 7.8 +/- 0.4 pg/mL; n = 71) during periods of estrus with multiple Ovulations despite a greater preovulatory follicular volume (4136 +/- 123 vs. 3085 +/- 110 mm(3)). Similarly, serum progesterone concentration 7 d after estrus was lower for cows with multiple than single Ovulations (2.5 +/- 0.3 vs. 3.2 +/- 0.1 ng/mL) despite a greater luteal volume (8291 +/- 516 vs. 6405 +/- 158 mm(3)). In summary, the first spontaneous Ovulation in anovular cows and a higher level of milk production for 14 d preceding estrus were associated with increased multiple Ovulation rate. Additionally, cows with multiple Ovulations had lower estradiol at estrus, a shorter duration of estrus, and lower progesterone at 7 d after estrus than cows with single Ovulations.
J M Sreenan - One of the best experts on this subject based on the ideXlab platform.
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effect of immunization against synthetic peptide sequences of the αn subunit of bovine inhibin on Ovulation rate gonadotrophin concentrations and fertility in heifers
Reproduction, 1995Co-Authors: D G Morris, M G Mcdermott, Maura Grealy, Michael G Diskin, C A Morrison, P J Swift, J M SreenanAbstract:The effects of immunizing cattle against either of two peptides from the amino terminal peptide (α N ) of the α 43 -subunit of bovine inhibin on Ovulation rate, gonadotrophin concentration and fertility were investigated. Two peptide sequences from the α N -subunit of bovine inhibin (P1N, bIα-(8-20) and P2N, bIα-(153-167)) were synthesized and conjugated to human serum albumin (HSA). Hereford-cross heifers (n=5 per group) were given an initial injection of 3 mg of one of the peptide conjugates, followed by three booster injections (1.5 mg) at intervals of 11 weeks. Control heifers (n=5) were injected with HSA only. Blood samples were taken once a week to measure antibody titre and every hour at about the time of the first oestrus and during the mid-luteal phase after the second booster injection, to measure FSH and LH concentrations. Ovulation rate was measured by ultrasonography. Gonadotrophin concentrations were analysed for four periods relative to the peak (time=0 h) of the preovulatory LH surge as follows: pre-surge: -16 to -5 h; surge: -4 to 4 h; post-surge: 5 to 16 h and a period of 12 h during the mid-luteal (days 10-12) phase. Antibodies that bound to the individual peptides were generated and the Ovulation rate increased (P<0.05) in immunized heifers. Control heifers had one Ovulation at all ovulatory cycles monitored. In group P1N, one heifer had two Ovulations at each of the six cycles monitored, while another heifer had two Ovulations at one cycle. Three heifers in group P2N had more than one Ovulation; one heifer had a superOvulation response on seven occasions and another heifer on three occasions while the third heifer had two Ovulations at one cycle. The superOvulation responses ranged from three to eight Ovulations. There was no evidence of a significant correlation between peptide antibody titre, Ovulation rate and FSH at any of the periods studied. After mating following the third booster injection, nine of the ten immunized and all five control heifers calved. One heifer from group PIN and two heifers from group P2N gave birth to twin calves. These data show that in cattle immunization against the α N -subunit of bovine inhibin significantly disrupts the mechanism(s) controlling Ovulation rate but does not impair fertility
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effect of immunization against synthetic peptide sequences of bovine inhibin α subunit on Ovulation rate and twin calving rate in heifers
Reproduction, 1993Co-Authors: D G Morris, M G Mcdermott, Michael G Diskin, C A Morrison, P J Swift, J M SreenanAbstract:Three peptide sequences from the bovine inhibin alpha-subunit (P1: 18-30; P2: 63-72 and P3: 107-122) were synthesized and conjugated to human serum albumin (HSA). Hereford cross-heifers (n = 5 per group) were injected with 3 mg of one of the peptide conjugates, followed by three booster injections at intervals of 11 weeks. Control heifers (n = 5) were injected with HSA only. Antibodies recognizing both the individual peptides and 32 kDa bovine inhibin were generated and Ovulation rate was increased in peptide immunized heifers. In group P1, 1 of 5 heifers responded with an increased Ovulation rate whereas in groups P2 and P3, 5 of 5 and 4 of 5 heifers, respectively, had an increased Ovulation rate. In group P2, in the first oestrous cycle following booster injections 2 and 3, 4 of 5 and 3 of 5 heifers, respectively, responded with twin Ovulations, whereas a fourth heifer had three Ovulations following booster injection 3. After breeding following booster injection 3, 3 of 5 heifers in group P2 and 1 of 5 in group P3 gave birth to twin calves. This study demonstrates the potential of immunizing against synthetic peptide sequences of the alpha-subunit of bovine inhibin to increase Ovulation and twinning rates in cattle.
H Lopez - One of the best experts on this subject based on the ideXlab platform.
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relationship between level of milk production and multiple Ovulations in lactating dairy cows
Journal of Dairy Science, 2005Co-Authors: H Lopez, D Z Caraviello, L D Satter, P M Fricke, M C WiltbankAbstract:Abstract Our objective was to evaluate factors associated with spontaneous multiple Ovulations in lactating dairy cows. Ovaries of cows [n=267; >50 days in milk (DIM)] were evaluated weekly using ultrasound to determine spontaneous (i.e., no hormonal treatment) Ovulation rate starting at 50 DIM and continuing until pregnancy diagnosis. Cows were fitted with a transmitter to record standing activity during estrus, and serum progesterone concentration was assessed weekly starting at wk 1 postpartum for all cows. Overall, 76 (28.5%) cows were anovular and 191 (71.5%) were ovular by 71 DIM. Incidence of anOvulation was not associated with level of milk production but was associated with lower body condition. For anovular cows (n=41) that spontaneously recovered, the multiple Ovulation rate at first Ovulation was 46.3%. For second and subsequent Ovulations (n=463), the level of milk production for 14 d preceding estrus was associated with increased Ovulation rate. To illustrate, incidence of multiple Ovulations was 1.6% (2/128), 16.9% (32/189), and 47.9% (70/146) for Ovulations when cows were producing 3 ). Similarly, serum progesterone concentration 7 d after estrus was lower for cows with multiple than single Ovulations (2.5±0.3 vs. 3.2±0.1 ng/mL) despite a greater luteal volume (8291±516 vs. 6405±158mm 3 ). In summary, the first spontaneous Ovulation in anovular cows and a higher level of milk production for 14 d preceding estrus were associated with increased multiple Ovulation rate. Additionally, cows with multiple Ovulations had lower estradiol at estrus, a shorter duration of estrus, and lower progesterone at 7 d after estrus than cows with single Ovulations.
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relationship between level of milk production and multiple Ovulations in lactating dairy cows
Journal of Dairy Science, 2005Co-Authors: H Lopez, D Z Caraviello, L D Satter, P M Fricke, M C WiltbankAbstract:Our objective was to evaluate factors associated with spontaneous multiple Ovulations in lactating dairy cows. Ovaries of cows [n = 267; >50 days in milk (DIM)] were evaluated weekly using ultrasound to determine spontaneous (i.e., no hormonal treatment) Ovulation rate starting at 50 DIM and continuing until pregnancy diagnosis. Cows were fitted with a transmitter to record standing activity during estrus, and serum progesterone concentration was assessed weekly starting at wk 1 postpartum for all cows. Overall, 76 (28.5%) cows were anovular and 191 (71.5%) were ovular by 71 DIM. Incidence of anOvulation was not associated with level of milk production but was associated with lower body condition. For anovular cows (n = 41) that spontaneously recovered, the multiple Ovulation rate at first Ovulation was 46.3%. For second and subsequent Ovulations (n = 463), the level of milk production for 14 d preceding estrus was associated with increased Ovulation rate. To illustrate, incidence of multiple Ovulations was 1.6% (2/128), 16.9% (32/189), and 47.9% (70/146) for Ovulations when cows were producing or=45 kg/d, respectively. Among cows for which estrous behavior was recorded, those with multiple Ovulations (n = 48) had shorter duration of estrus (4.3 +/- 0.7 vs. 9.9 +/- 0.5 h) and higher production (47.2 +/- 0.9 vs. 38.1 +/- 0.5 kg/d) than cows with single Ovulations (n = 237). Circulating concentrations of estradiol were lower (5.5 +/- 0.3; n = 15 vs. 7.8 +/- 0.4 pg/mL; n = 71) during periods of estrus with multiple Ovulations despite a greater preovulatory follicular volume (4136 +/- 123 vs. 3085 +/- 110 mm(3)). Similarly, serum progesterone concentration 7 d after estrus was lower for cows with multiple than single Ovulations (2.5 +/- 0.3 vs. 3.2 +/- 0.1 ng/mL) despite a greater luteal volume (8291 +/- 516 vs. 6405 +/- 158 mm(3)). In summary, the first spontaneous Ovulation in anovular cows and a higher level of milk production for 14 d preceding estrus were associated with increased multiple Ovulation rate. Additionally, cows with multiple Ovulations had lower estradiol at estrus, a shorter duration of estrus, and lower progesterone at 7 d after estrus than cows with single Ovulations.
Ilpo Huhtaniemi - One of the best experts on this subject based on the ideXlab platform.
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knockout of luteinizing hormone receptor abolishes the effects of follicle stimulating hormone on preovulatory maturation and Ovulation of mouse graafian follicles
Molecular Endocrinology, 2005Co-Authors: Tomi Pakarainen, Fuping Zhang, Laura Nurmi, Matti Poutanen, Ilpo HuhtaniemiAbstract:It is considered a dogma that a secretory peak of LH is indispensable as the trigger of Ovulation. However, earlier studies on hypophysectomized rodents have shown that stimulation with recombinant FSH, devoid of any LH activity, is able to boost the final stages of follicular maturation and trigger Ovulation. As the expression of ovarian LH receptors (LHRs) still persists after hypophysectomy, such studies cannot totally exclude the possibility that LHR activation is involved in the apparently pure FSH effects. To revisit this question, we analyzed in LHR knockout (LuRKO) mice the progression of folliculogenesis and induction of Ovulation by human chorionic gonadotropin and human recombinant FSH treatments. The results provide clear evidence that follicular development and Ovulation could not be induced by high doses of FSH in the absence of LHR expression. Ovarian histology and oocyte analyses indicated that follicular maturation did not advance in LuRKO mice beyond the antral follicle stage. Neither were Ovulations detected in LuRKO ovaries after any of the gonadotropin treatments. The ovarian resistance to FSH treatment in the absence of LHR was confirmed by real-time RT-PCR and immunohistochemical analyses of a number of gonadotropin-dependent genes, which only responded to the treatments in wild-type control mice. Negative findings were not altered by estradiol priming preceding the gonadotropin stimulations. Hence, the present study shows that, in addition to Ovulation, the expression of LHR is essential for follicular maturation in the progression from antral to preovulatory stage.
