8 Evaluation of puberty induction protocol in peripubertal beef heifers prior to fixed-time AI programs

2019 ◽  
Vol 31 (1) ◽  
pp. 129
Author(s):  
J. B. S. Borges ◽  
D. S. V. Luiz ◽  
P. R. L. Aguiar ◽  
C. G. B. Berlitz ◽  
G. S. Velho ◽  
...  

Beef heifers that conceive early during their first breeding season calve earlier, wean heavier calves, and tend to continue doing so throughout the rest of their reproductive lives. Otherwise, under extensively managed systems in Southern Brazil, only a variable proportion of 2-year-old beef heifers reach puberty before the start of the breeding season. The aim of this study was to evaluate a protocol to induce puberty in peripubertal beef heifers using injectable progesterone (P4) and oestradiol cypionate (EC) to improve pregnancy per AI (P/AI) in fixed-time AI (FTAI) programs. A total of 311 Angus heifers, 24±3 months of age, 3.1±0.3 body condition score (1=emaciated; 5=obese), and 328±41kg of body weight (BW), were examined before FTAI protocol (Day −24) by transrectal ultrasonography to determine reproductive tract score (RTS; 1=prepubertal; 5=pubertal). Prepubertal heifers (RTS 1; 12.8%, 40/311) were excluded from the study. Heifers with RTS=2 (n=271) were assigned to 2 groups: P4 (RTS 2 or 3, n=100) and cyclic (RTS 4 and 5, n=171). Peripubertal heifers were treated on Day −24 with 150mg of injectable P4 IM (Sincrogest® injectable, Ourofino Animal Health, Cravinhos, Brazil) and on Day −12 received 1mg of EC IM (Sincro CP®, Ourofino Animal Health). Cyclic heifers received no hormonal treatment before FTAI protocol. On Day 0, heifers in the P4 group were evaluated again to determine RTS, body condition score, and BW. Induction of puberty was defined by the presence of a follicle >8.5mm (RTS=4) or a corpus luteum (RTS=5). All heifers received an FTAI protocol consisting of 2mg of oestradiol benzoate IM (Sincrodiol®, Ourofino Animal Health) and an intravaginal progesterone implant (1 g; Sincrogest®, Ourofino Animal Health). On Day 8, heifers had implants removed and were injected with 1mg of EC and 500µg of sodium cloprostenol IM (Sincrocio®, Ourofino Animal Health). After 48h, all heifers received an FTAI. Thirty days after AI, the diagnosis of gestation was performed by ultrasonography. Statistics included chi-square and linear regression with coefficients analysed as independent variables, considering a significant P-value of 0.05. On Day 0, percentages of RTS 5, 4, and 3 in the P4 heifers were 37, 27, and 36%, respectively, resulting in 64% of puberty induction. The P/AI was similar (P=0.14) in P4-treated and cyclic heifers (59v. 50.3%, respectively). The regression analysis presented a linear and positive effect of BW on P/AI (P<0.001) in cyclic heifers and a positive influence of BW on RTS (P=0.05) and RTS on P/AI (P=0.008) in P4-treated heifers. The application of RTS system associated with P4 treatment of peripubertal heifers before FTAI protocol improved ovarian activity and might have contributed to higher P/AI, comparable with that achieved in cyclic heifers.

2021 ◽  
Vol 33 (2) ◽  
pp. 164
Author(s):  
C. G. Pintos ◽  
R. Núñez-Olivera ◽  
F. Cuadro ◽  
C. Brochado ◽  
G. A. Bó ◽  
...  

The objective was to evaluate the effect of different doses of equine chorionic gonadotrophin (eCG) on pregnancy (P/AI) and twin rates of beef heifers in a progesterone and oestradiol-based treatment (J-Synch protocol) for fixed-time AI (FTAI). A total of 1,404 Bos taurus beef heifers with a body condition score 4.8±0.5 (mean±s.e.m., scale 1–8) were used in three different locations. The presence of a corpus luteum (CL) was determined by ovarian ultrasonography (5.0MHz) at the beginning of the J-Synch protocol. On Day 0, the heifers received 2mg of oestradiol benzoate (intramuscular, IM) associated with an intravaginal device containing 0.5g of progesterone. At device removal, on Day 6, 500µg of cloprostenol sodium was administered IM and the females were randomly assigned to one of two experimental groups to receive 200 (n=702) or 300 (n=702) IU of eCG (Zoetis) IM. Heifers were also tail-painted. On Day 0 females with paint rubbed-off were FTAI 64 h after device removal, and those that remained with the paint received 8 μg of buserelin acetate 64 h after device removal to be FTAI 8 h later. FTAI was performed at 64 to 72h after device removal, and pregnancy diagnosis was performed by ultrasonography 30 to 35 days after insemination. Data were analysed by logistic regression using GLMM. The results are shown in Table 1. Pregnancy rate was not different between heifers treated with 200 or 300IU of eCG (P=0.513) and was not affected by the presence of CL at the beginning of the protocol (P=0.513). Twin rate was greater in heifers treated with 300IU than with 200IU of eCG (P=0.005), and it was not affected by the presence of CL (P=0.362). Interaction between eCG treatment and presence of CL was not significant for pregnancy or twin rates (P=0.532). In conclusion, although 300IU of eCG increased the twin rate compared with 200IU, no differences were found in P/AI. We suggest that the dose of eCG in the J-Synch protocol could be adjusted to 200IU in Bos taurus beef heifers. Table 1. Pregnancy per AI (P/AI) and twin rates obtained with different doses of eCG (200 or 300IU) in a J-Synch protocol for fixed-time AI in cycling (CL) and anestrous (no CL) Bos taurus beef heifers Variable 200 IU 300 IU P-value CL no CL Total CL No CL Total eCG CL eCG×CL P/AI (%) 61.6% (135/219) 59.8% (289/483) 60.4% (424/702) 60.2% (133/221) 59.5% (286/481) 59.7% (419/702) 0.513 0.513 0.513 Twin rate (%) 3.0% (4/135) 3.5% (10/289) 3.3% (14/424) 6.8% (9/133) 9.4% (27/286) 8.6% (36/419) 0.005 0.362 0.532


2010 ◽  
Vol 22 (1) ◽  
pp. 177 ◽  
Author(s):  
M. Ramos ◽  
L. Cutaia ◽  
P. Chesta ◽  
G. A. Bó

Two experiments were designed to evaluate the effect of the timing of fixed-time AI (FTAI) in relation to the removal of an intravaginal progesterone-releasing device (1 g of progesterone, DIB, Syntex SA, Buenos Aires, Argentina) on pregnancy rates in Bos indicus × Bos taurus cross-bred heifers. In experiment 1, 285 Bonsmara × zebu cross-bred heifers, between 18 and 24 months of age and with a body condition score (BCS) between 3.0 and 3.5 (1-5 scale) were used. On the day of initiation of treatment (Day 0), the heifers’ ovaries were palpated (92% of them had a CL) and they received a new DIB plus 2 mg of estradiol benzoate (EB; Syntex SA) and 250 μg of cloprostenol (Ciclase DL, Syntex SA). On Day 8, DIB devices were removed and all heifers received 250 μg of Ciclase plus 0.5 mg of estradiol cypionate (ECP; Cipiosyn, Syntex SA). At that time the heifers were randomly divided to receive FTAI between 48 to 49 h, 53 to 54 h, or 58 to 59 h after DIB removal. The heifers underwent FTAI with semen from 4 bulls by 2 inseminators. In experiment 2, 260 heifers from the same group as those used in experiment 1 (87% with a CL) were treated exactly as those in experiment 1, except that previously used DIB was inserted on Day 0. Pregnancy diagnosis was performed 30 days post-fixed-time AI by ultrasonography. The data were analyzed by logistic regression, taking into account the effect of time of FTAI, semen, and inseminator on pregnancy rates. In experiment 1, pregnancy rates were lower (P = 0.04) in the heifers undergoing FTAI between 48 and 49 h after DIB removal (46/95, 48.4%) than those undergoing FTAI 53 to 54 h (61/99, 61.6%) or 58 to 60 h (57/91, 62.6%) after DIB removal. However, no differences in pregnancy rates were found (P = 0.72) in experiment 2 between the 3 treatment groups, with 39/91 (42.9%) for the 48 to 49 h group, 45/89 (50.6%) for the 53 to 54 h group, and 35/89 (43.8%) for the 58 to 59 h group. There was no effect of the semen or inseminator (P > 0.2) in either experiment. We conclude that when Bos indicus × Bos taurus beef heifers are synchronized with new DIB devices and ECP, higher pregnancy rates are obtained in heifers undergoing FTAI late (between 53 to 60 h after DIB removal) than in those undergoing FTAI early (48 to 49 h after DIB removal). However, time of insemination does not apparently affect pregnancy rates when Bos indicus × Bos taurus beef heifers are synchronized with previously used DIB devices and ECP.


2010 ◽  
Vol 22 (1) ◽  
pp. 247
Author(s):  
J. R. V. Pimentel ◽  
P. H. P. Miguez ◽  
A. Kehrle ◽  
E. H. Madureira ◽  
F. A. Braga ◽  
...  

Progestagen-releasing devices are commonly used for fixed-time artificial insemination and fixed-time embryo transfer (FTET). The aim of this study was to evaluate the efficacy of a new progesterone-releasing intravaginal device made of poly(3-hydroxy)butyrate-valerate copolymer (PHB-V) and poly-ϵ-caprolactone (PCL; Progestar®, Innovare, São Paulo, Brazil) to synchronize crossbredcows and heifers for FTET by determining ovulation, conception, and pregnancy rates. A total of 205 recipients ranging in age from 2 to 8 years (heifers, n = 77; non-suckled cows, n = 69; suckled cows, n = 59) were used on 3 different farms during February, March, and April 2008. The experimental design was a generalized block design (cyclicity, body condition score, postpartum interval, and animal category, i.e. heifers, suckled, or non-suckled cows), with 2 different synchronization treatments for FTET (Progestar® v. Crestar®). Cows were assigned to either Crestar® (norgestomet ear implants; Intervet Schering-Plough, Kenilworth, NJ, USA; n = 103) or Progestar® (PHB-V; n = 102) treatments. All groups were treated with 2 mg of estradiol benzoate i.m. (Innovare) and received the intravaginal or auricular device according to their group (Day 0). Together with P4 device withdrawal (Day 8), all animals received 400 IU of eCG i.m. (Novormon®, Schering-Plough) and 500 μg i.m. of PGF2α, (Sincrocio®, Ouro Fino, Brasil). On Day 9, all cows were treated with 1 mg of estradiol benzoate (Innovare) and the innovulation was performed on Day 17. Embryos were maintained at 37°C during the innovulation period. The percentage of usable recipients (AR) based on the presence of a functional CL on the day of embryo transfer, conception rate (numbers of pregnant recipients of the total number transferred; CR), and pregnancy rate (numbers of pregnant recipients of the total number synchronized; PR) were determined by ultrasonography 23 days after embryo transfer. Data were submitted to ANOVA (PROC GLM, SAS Institute Inc., Cary, NC, USA) and significant differences were considered to have a P-value of <0.05. None of the interactions were significant and there was no effect of treatment on AR (72.8% v. 83.3%), CR (47.9% v. 42.7%), and PR (34.7% v. 35.0%) for Progestar® v. Crestar® groups, respectively. This experiment showed that Progestar® was as efficacious as Crestar® to synchronize crossbred cows and heifers for FTET. FAPESP-Fundação de Amparo à Pesquisa do Estado de São Paulo and CNPq-Conselho Nacional de Desenvolvimento Científico e Tecnológico.


2015 ◽  
Vol 31 (2) ◽  
pp. 235-243
Author(s):  
P. Slavova ◽  
S. Laleva ◽  
Y. Popova

?bject of the study were merino sheep raised in the farm of the Agricultural institute - Stara Zagora. The experiment was conducted with a group of 68 animals of different ages, lambing after treated with hormonal preparation according to adopted scheme during the out-of-breeding season - in May. In the experimental group were included ewes which lambed earlier without making a selection in respect to their productivity. Animals were kept under the same conditions (stall-pasture) and fed the same rations with the concentrate mixture, rough, succulent feed and grazing in quantity and composition according to their physiological status and season from the fertilization until lambing. Hormonal pattern: setting pads for sheep type Sincro-part (30mg), removing pads after 12 days and giving ewes a PMSG injection at a dose of 500 UI, applying artificial insemination at the 50-55th hour. Body condition score and live weight of the animals were determined in 4 separate periods: 1st period (after mating), 2nd period (during pregnancy), 3rd period (after lambing), 4th period (before next mating service). Improving fertility in merino sheep is significantly influenced by the preparation of ewes for the mating by reaching the respective physiological status which is expressed by score over 2.5 according to the Body condition score method and live weight over 60 kg. Animals scored 2.75-3.50 before mating have a share of 91.18% from all the sheep in the flock and have the biggest number of lambs.


2017 ◽  
Vol 33 (2) ◽  
pp. 181-191
Author(s):  
Benjamin Cengic ◽  
Nazif Varatanovic ◽  
Tarik Mutevelic ◽  
Amel Cutuk ◽  
Ermin Saljic

Clinical and subclinical disorders and diseases cause reproductive failures and decline in milk production. Etiology of disorders is mainly because of pathological effect of microorganisms, lapses in nutrition and lodging, as well as in management. After partrition, body is under stress and milk yield is highest, which favors appearance of metabolic and infective diseases. Status of puerperium, number of lactation, body condition score and season of parturition, have highest effect to cyclic ovarian activity. Regular development of dominant follicles, ovulation, formation of corpus luteum and luteolysis is necessary for establishment of regular cyclic ovarian activity, which leads to better fertility. Experiment had included 50 cows during first 52 days of lactation. Cows were separated in two main groups, those with normal puerperium - NP (n=32) and abnormal puerperium - AP (n=18). Examinations have been performed during period of 6 to 52 days postpartum. Ovarian dominant follicles have been observed using diagnostic ultrasound linear scanner. The highest number of dominant follicles are present during first two examinations, then their number declines and later in last two examinations rise again. Decrease in number of dominant follicles in both groups is most expressed in period of 14-30 days. During first examination, left ovaries have more dominant follicles, compared with right ovaries, while during later examinations, it is changed in favor of right ovaries. Increased number of vital dominant follicles from period 38-45 days postpartum and absence of abnormal uterine content in lumen in same period postpartum is sign of upcoming fertile estrus.


2012 ◽  
Vol 24 (1) ◽  
pp. 227 ◽  
Author(s):  
R. S. Surjus ◽  
A. B. Prata ◽  
M. Borsato ◽  
M. C. Martins da Silveira ◽  
M. C. C. Mattos ◽  
...  

The aim of this study was to evaluate the influence of high or low dry matter (DM) intake and/or energy on embryo quality and production in vivo. Nonlactating Nelore cows (n = 32, 4 to 10 years old) weighing 489.5 ± 11.3 kg and with a body condition score of 3.25 (1 to 5) were used. After 15 days on the adaptation diet, cows were blocked by initial body weight (BW) and randomly divided in 4 experimental groups. The maintenance group (M) received a diet to provide 1.2% of DM/kg of BW. The restriction group (0.7M) received the equivalent of 70% of the group M diet (0.84% of DM per kg of BW). The high intake group (1.5M) received the equivalent of 150% of the M group (1.8% of DM/kg of BW). The energy group (E) received a diet with a DM similar to the M group but with an energy level equivalent to the 1.5 M group. All cows were submitted to aspiration of follicles >2 mm for ovum pick-up (OPU). Recovered oocytes were used in another experiment. The embryo donors received an intravaginal device (IVD) of progesterone release (Sincrogest®, Ouro Fino, Ribeirão Preto, Brazil), soon after OPU. Two days after OPU, the cows received 8 decreasing doses of FSH (100 mg, IM, Folltropin-V®, Bioniche Animal Health, Belleville, Ontario, Canada) and concomitant with the fifth and sixth treatments of FSH, PGF2α (500 μg each, IM, cloprostenol, Sincrocio®, Ouro Fino) was administered. The IVD was removed at the time of the last FSH injection. Twelve hours after IVD removal ovulation was induced with GnRH (0.01 mg, IM, Buserelin acetate, Sincroforte®, Ouro Fino). Cows were inseminated 12 and 24 h later. Embryo collection was performed 7 or 8 days after GnRH injection. The cows were offered all diets in a crossover design study. There were 4 sessions of embryos flushing, each 42 days apart. Data were analysed by PROC GLIMMIX of SAS (SAS Institute Inc., Cary, NC, USA) and the results are presented as least-squares means ± SE, always following the order of treatments 0.7 M, M, 1.5 M and E. There were differences in the superstimulatory response (12.6 ± 1.4b; 14.6 ± 1.6a; 13.6 ± 1.5ab; and 11.0 ± 1.2c follicles >6 mm; P < 0.01) and superovulatory response (9.8 ± 1.3ab; 11.0 ± 1.4a; 10.2 ± 1.3a; and 8.6 ± 1.3b CL; P < 0.01) among groups. Despite the lower responses observed especially in the high-energy group, no difference among groups was observed for total embryos/ova (4.5 ± 0.7; 5.0 ± 0.8; 5.0 ± 0.8; and 4.7 ± 0.7; P = 0.60), viable embryos (2.0 ± 0.4; 2.3 ± 0.5; 2.6 ± 0.6; and 2.2 ± 0.5; P = 0.40), or freezable embryos (1.7 ± 0.4; 2.0 ± 0.4; 2.1 ± 0.5; and 1.9 ± 0.4; P = 0.60). There was also no difference among groups for fertilization rate (75.8 ± 9.6; 82.3 ± 8.0; 87.8 ± 6.6; and 81.1 ± 8.4%; P = 0.71) and percentage of viable embryos (54.5 ± 10.8; 50.8 ± 10.6; 50.5 ± 10.9; and 54.4 ± 10.7%; P = 0.98). In conclusion, in contrast to our initial hypothesis, a period of 42 days under high feed/energy intake in nonlactating zebu cows apparently did not compromise in vivo embryo production. This may be because cows had a moderate body condition score or because the feeding period was not long enough to compromise oocyte/embryo quality. Financial support from FAPESP and CNPq is acknowledged.


2010 ◽  
Vol 22 (1) ◽  
pp. 174
Author(s):  
V. A. Nascimento ◽  
G. S. Moura ◽  
M. Dias ◽  
F. A. Oliveira ◽  
A. R. Dias ◽  
...  

The objective of this study was to evaluate the administration of the follicle-stimulating hormone (FSH-p) or equine chorionic gonadotropin (eCG) in protocols of ovulation synchronization. One hundred forty-nine crossbred Holstein-Gyr cows were used in 2 properties in Minas Gerais and 3 treatments: TControl (n = 49 cows), Day 0: insert of a progesterone device (Primer®, Tecnopec, São Paulo, Brazil) + 2 mg of estradiol benzoate (RIC-BE®); Day 8: removal of Primer + 112 mg of D-cloprostenol (Prolise®, ARSA SRL, Buenos Aires, Argentina) + 1 mg of estradiol benzoate and fixed-time artificial insemination (FTAI) accomplished 44 h after the removal of Primer; TFSH (n = 50 cows), similar to TControl, but on Day 8, 15 mg of FSH-p (Folltropin®, Bioniche Animal Health) was administered; TeCG (n = 50 cows), similar to TControl, with administration on Day 8 of 300 IU of eCG (Novormon®, Syntex SA, Buenos Aires, Argentina). Cows that returned to estrus 14 to 28 days after the FTAI were inseminated once again. For all statistical analysis, we used the program SAS 9.0 (2002; SAS Institute Inc., Cary, NC, USA) at 5% probability. Quantitative variables (live weight, days postpartum, follicular average per cow) were analyzed by variance, and body condition score by Friedman test. The pregnancy rates were submitted to logistic analysis considering the effect of local experimental factors and were analyzed by Spearman correlation among the variables studied and the pregnancy rate. There was no difference (P > 0.05) between treatment for pregnancy rate in FTAI protocols (TControl = 40.82%; TFSH = 38.00%; TeCG = 26.00%), in the first insemination after FTAI (TControl = 56.25%; TFSH = 70.59%; TeCG = 68.42%), and in FTAI plus first insemination after FTAI (TControl = 59.18%; TFSH =62.00%; TeCG = 52.00%), as well as for the estrus repetition (TControl = 55.17%; TFSH = 54.84%; TeCG = 51.35%) and the correlation (P > 0.05) among the pregnancy rate and postpartum period, milk production, body weight and body condition. No effect was observed on the pregnancy rate by the addition of the hormones FSH and eCG in the protocol of ovulation synchronization in crossbred Holstein-Gyr cows; however, reinsemination in the period from 14 to 28 days after FTAI increased the pregnancy rate. CNPq; FAPEMIG; TECNOPEC/São Paulo, Brazil.


Sign in / Sign up

Export Citation Format

Share Document