Hormonal Protocols Research Articles

A new hormonal protocol supports early development of invitro-produced embryos after transfer to anoestrus mares.

The present study aimed to evaluate whether primed anoestrus mares are suitable recipients for embryos produced by intracytoplasmic sperm injection (ICSI). Anoestrus was confirmed in four mares and daily doses of oestradiol benzoate (6 mg in total) over 5 days were administered; after 3 days of rest, oral altrenogest was administered at 0.088 mg/kg and embryos (1 to 5 embryos per mare; 15 in total) were transferred 3.5 days after progesterone onset. Uterine lavage was conducted 48 h after transfer. The results revealed an 80% embryo recovery rate, and among the retrieved embryos, 67% showed evident intrauterine development. Hence, ICSI-derived embryos can be successfully transferred to primed anoestrus mares, but more studies are required to ensure further embryo development and foaling.

Is it possible to replace eCG by GnRH in the hormonal protocol for timed artificial insemination in ewes during the breeding season?

Hormonal protocols based on progestogens and equine chorionic gonadotrophin (eCG) are efficient for estrus and ovulation synchronization in ewes. Although eCG is indispensable during seasonal anestrus, it may not be necessary during the breeding season. Thus, we tested the hypothesis that GnRH is effective in replacing eCG during the breeding season allowing satisfactory ovulation rate, luteal function and conception rates after timed artificial insemination (TAI). Ewes (n = 134) with a minimum body condition score of 2.5 (0–5 scale) were treated with intravaginal devices (IVD) containing 60 mg of medroxyprogesterone acetate (MPA) for seven days and received 0.26 mg of sodium cloprostenol at the time of IVD removal. In Exp. 1, at IVD removal, ewes (n = 29) were allocated to three groups: eCG (200 IU at IVD removal; n = 10); eCG+GnRH (200 IU eCG at IVD removal and 4 µg of buserelin 36 h later; n = 10); or GnRH (buserelin 36 h after IVD removal; n = 9). Blood samples were collected 2, 6 and 12 days after TAI moment (54 h after IVD removal), for progesterone (P4) analysis. In Exp 2, the ewes were allocated to eCG (n = 10) or GnRH (n = 10) groups, as above described, and ovulation moment was evaluated 54, 66 and 78 h after IVD removal. In Exp 3, TAI was performed in ewes from eCG (n = 45) and GnRH (n = 40) groups using 100 × 106 motile spermatozoa from a pool of semen collected from four rams. In Exp. 1, based on P4 levels, we confirmed that all the ewes ovulated (29/29) and there was no significant effect of group (P = 0.89) or group x day (P = 0.18) on P4 concentration, being observed a significant effect of day (P = 0.0001). In Exp. 2, the maximum DF diameter (P = 0.26) and ovulation moment (P = 0.69) did not differ between groups. In Exp. 3, pregnancy rate was significantly lower (P = 0.02) in GnRH (22.5 %; 9/40) compared to eCG (46.7 %; 21/45). The results indicate that, although ovulation and luteal function were not altered after eCG, eCG+GnRH or GnRH treatment, GnRH alone before TAI cannot be used to replace eCG treatment during the breeding season.

Fixed-Time Artificial Insemination Versus Artificial Insemination at Stalk Detected in Cows And Heifers

Objective: The objective of the present study was to evaluate the pregnancy rate of IACD and IATF in cows and heifers. Theoretical framework: Artificial insemination at a fixed time (IATF) and artificial insemination at detected heat (IACD) are essential tools in livestock farms, improving the production and reproduction of the herd in a short time, considering that differences sometimes occur between the pregnancy rate of cows and heifers with different treatments influencing the production of the herds. Methodology: 194 heifers and 200 Bos taurus x Bos indicus crossbred cows were used. The animals that entered IATF on a random day of the estrous cycle were synchronized with an intravaginal device of Progesterone and Estradiol. The animals that entered IACD were monitored. visual of the characteristic signs of heat twice a day for a period of two hours each, to carry out artificial insemination (AI), the statistical analysis was carried out with the help of the SAS software. Results and discussion: The pregnancy rate among the 215 heifers and cows in the IACD group was 64.00% and 44.00%, respectively, unlike the IATF group with a total of 179 animals, a pregnancy rate of 91.14% for heifers and 78.00% in cows, showing statistically significant differences in follicular size for cows and heifers under treatment with IACD and similar for IATF. Implications of the research: The cyclicity of heifers was efficiently induced in the hormonal protocols with IATF, this group of animals had a higher pregnancy rate and greater follicular diameter unlike the IACD group. Originality/Value: This study contributes to the understanding and effectiveness of using reproductive biotechnologies in livestock herds to increase production and profitability, thus being more sustainable.

Efficacy of omitting initial GnRH in once-used CIDR co-synch protocol for the treatment of anestrus in buffaloes during low breeding season

Progesterone-based hormonal protocols are effective to treat anestrus in buffaloes. However, most of those protocols are costly, thus, requiring a cost-effective protocol that minimizes handling frequencies. This study, therefore, evaluated the effectiveness of the ‘once-used CIDR co-synch protocol’ with or without initial GnRH for treating anestrus in buffaloes during low breeding season. Anestrous buffaloes (n=29) were divided into two Treatment groups. As a part of the ‘once-used CIDR co-synch protocol,’ the first group (T1, n=18) received an initial GnRH on a random day (day 0) while the second group (T2, n=11) did not receive it. On day 0, the once-used CIDR device was inserted intravaginally in both groups, with GnRH administered in T1 but omitted in T2. On day 7, during CIDR removal, each buffalo received PGF2α, and on day 10, GnRH was given, and fixed-timed artificial insemination (FTAI) was done. Ovarian status was assessed on d0 and on 8 to 9-day post-FTAI using transrectal ultrasonography. Plasma progesterone concentrations on 8 to 9-day post-FTAI were determined using ELISA. No significant differences in estrus expression, ovulation and pregnancy rates were observed between two Treatment groups, with overall rates of 93%, 69%, and 34.5%, respectively. However, the overall pregnancy outcome (from FTAI plus natural breeding of buffaloes that returned to estrus) up to 2 months post-FTAI was 48.3%. Parity affected the ovulation among treated buffaloes, with higher (P=0.04) ovulation rate in buffaloes ≤4th parity (79.2%) compared to >4th parity (20%). There were no differences in CL size and plasma progesterone concentrations during 8 to 9-day post-FTAI between two treatment groups. In conclusion, omitting the initial GnRH in ‘once-used CIDR Co-synch protocol’ proved equally effective as the protocol with initial GnRH for the treatment of anestrus in buffaloes during the low breeding season.

Evaluation and Comparison of Therapeutic Efficacy of Various Hormonal Protocols in Anoestrus Buffalo Heifers of Semi-Arid Region

To assess and compare different hormonal protocols' treatment efficacy in anoestrus buffalo heifers in a semi-arid region. Forty buffalo heifers with a history of anoestrus were chosen randomly from the semi-arid region of Banaskanth and divided into four equal groups.Group-I: Heatsynch protocol (n = 10), Group-II Ovsynch protocol (n = 10), Group-III Doublesynch protocol (n = 10) and Group-IV Control (n = 10) are followed by artificial insemination at a predetermined period in treated buffalo heifers and insemination during spontaneous estrus in group-IV buffalo heifers. In Groups I, II, and III, the corresponding percentages of estrus induction were 90, 80, and 80 percent. Major symptoms such as edoema, erythema, dampness of vulva and estrus mucus secretion were present during the expression of estrus. Fifty percent of the buffalo heifers in Group IV displayed estrus at varying intervals. After three consecution services, Group II had the highest overall fertility rate (50%) followed by Group III (40%), Group I (30%), and Group IV (30%). In true anoestrus buffalo heifers, the Heatsynch, Ovsynch, and Doublesynch procedure can be applied with success to induce estrus. Buffalo heifers that follow the Ovsynch protocol may have a higher conception rate.

Induction of puberty vs. induction of ovulation using steroid hormones in beef heifers: a comprehensive review.

This review elucidates the physiological and endocrinological processes intrinsic to puberty and ovulation induction protocols in Bos indicus and Bos taurus beef heifers. Puberty is a complex physiological event involving gonadotropic and metabolic changes that lead to sexual maturity, first ovulation, and regular reproductive cycles, enabling females to reproduce. Exposure to progesterone-based hormonal protocols, with or without additional hormones, can reduce the age at first ovulation and improve sexual maturity through stimuli in the hypothalamus-pituitary-gonadal (HPG) axis and uterine development. However, inducing puberty differs from inducing ovulation, as it does not ensure the heifer will continue cycling or be ready to establish and maintain pregnancy after hormonal exposure. Regardless of the pharmacological basis, studies consistently report that beef heifers that had a corpus luteum (CL) prior to the timed-artificial insemination (TAI) protocol, have greater expression of estrus in response to synchronization and greater pregnancy per AI compared to heifers without a CL. The combination of P4 and E2 significantly impacts uterine development, increasing reproductive efficiency. Exposure to P4 causes a positive effect on inducing ovulation. However, studies indicate that the addition of E2 esters at the time of P4 device removal increases the ovulation rate. In general, the studies showed that fertility varied according to the type of the ovulation induction protocol used, but with inconsistent results. Although ovulation induction protocols are strategic tools to accelerate sexual maturity, a holistic view of the entire system is extremely important, combining integration with genetics and nutrition to enhance the reproductive outcomes of beef heifers. Future research is needed to understand and refine these protocols, driving the efficiency of beef cattle production systems.

Luteal tissue characteristics of Morada Nova ewes with hCG application 7.5 days after the end of estrus synchronization protocol in the breeding season

Results with the use of hCG after synchronization protocol are still inconsistent, which may vary according to breed, season, day of application and dose of the drug used. The aim of the present study was to evaluate the functionality of luteal tissue and ovarian perfusion after hCG treatment during early luteal phase. Estrus-synchronized ewes were randomly assigned to receive i.m. injection of 300 IU of hCG (G-hCG; n = 40) or 1 mL of saline (G-Control; n = 32) on Day 7.5 after progesterone withdrawal. Ultrasonographic evaluations of the ovaries and ovarian and iliac arteries were performed on Days 7.5, 10.5, 13.5, and 21.5. The accessory corpus luteum (aCL) formation rate was 52.5% for G-hCG. There was interaction (p > 0.05) for treatment (G-hCG and G-Control), days (7.5, 10.5, 13.5 and 21.5) and PD (Pregnant and Non-pregnant) for the variables of biometric characteristics of the corpus luteum B-Mode and Color Doppler on days 7.5, 10.5, 13.5 and 21.5. There was no difference (p > 0.05) for pregnancy rates and mean fetuses per ewe between the treatment groups. It is concluded that the application of hCG 7.5 days after the hormonal protocol in Morada Nova ewes in a breeding season is efficient in inducing aCL formation and increasing luteal tissue biometry. However, there was no effect on pregnancy rate.

Impact of different hormonal protocols for the treatment of smooth inactive ovaries (SIO) and the subsequent reproductive performance in dairy cows

Impact of different hormonal protocols for the treatment of smooth inactive ovaries (SIO) and the subsequent reproductive performance in dairy cows

Ruling out Efficacy of Hormonal Protocols alone or Fortified with Mineral and Bypass Fat for Treatment of Postpartum Anoestrus in Cattle

Background: High milk production and excellent fertility is a dream of livestock owners.The major reproductive disorders which lead to decrease the productivity and reproductive ability of farm animals is postpartum anestrous.Recently, kisspeptin was reported as game changer in the animal reproduction. Kisspeptin increases the number of follicles at wave emergence, oestrus response rate and duration of oestrus. Thus, indicating its potentiality for induction of oestrus in anestrous animals. Methods: The present study was conducted to compare the efficacy of Ovsynch and kisspeptin protocol and need of fortification for treatment of postpartum anestrous.Fifty postpartum anestrous cows were selected. The animals were divided into four treatment groups (10 cows in each) and treated with Ovsynch (Group I), Ovsynch fortified with mineral mixture (MM) and bypass fat (BPF) (Group II), kisspeptin (Group III) and kisspeptin fortified with MM +BPF (Group IV). The remaining 10 cows served as control (Group V). The oestrus response was recorded on the basis of behavioral signs, physical signs and clinico-gynaecological changes. The blood was collected following treatment for hormonal estimation. The pregnancy was confirmed on day 45 post AI using ultrasound. Result: The oestrusresponse was pronounced in Ovsynch as compared to kisspeptin groups. Further, fortification has enhanced the response. The serum oestrogen concentration increased following treatment and was significantly high on day of onset of oestruswith highest concentration in group II. The results indicate Ovsynchdistinguishly succeeded in addressing postpartum anestrus with fortification enhances fertility response.However, kisspeptin also emerged as a potent candidate for the resumption of cyclicity.

Assessing the acceptability of hormone-based estrus induction / synchronization protocols to overcome anestrus in buffaloes

Five hundred dairy households in the rural areas of Punjab state were interviewed through comprehensively designed questionnaires to assess the knowledge and experience of farmers regarding the hormone-based strategies to overcome anestrus and getting the buffaloes pregnant. About 81.8% dairy households were unaware (P<0.05) about any estrus induction or synchronization hormonal protocol and majority (65.5%) of these belonged to households with <5 animals. Out of households having awareness about hormonal protocol use in buffaloes, the majority (58.2%) belonged to households with >15 animal. Out of dairy farmers using hormonal protocols, the proportion of illiterate was 14.8%. Out of dairy farmers not aware about hormonal protocols, the proportion of illiterate was 52.3%. Data analysis of 91 dairy households who had used hormonal protocols revealed summer (65.9%) and anestrus (82%) as the major underlying reasons for their use in buffaloes. Low success rate (20.2%), high cost (50%) and non-availability of doctor (29.7%) were the reasons for the irregular use of hormonal protocols. The success rate of hormonal protocols under field condition in terms of conception was 47.1%. In summary, the major bottlenecks in acceptability of hormone-based therapeutics strategies under filed conditions are illiteracy, high cost of therapeutics strategies and lack of awareness in buffalo farmers especially in households with <5 animals.

Effects of 17β-estradiol on the uterine luteolytic cascade in bovine females at the end of diestrus

In cattle, 17β-estradiol (E2) is essential for triggering luteolysis via the synthesis of prostaglandin F2α (PGF2α). We aimed to evaluate the effects of E2-treatment on day 15 of the estrous cycle on the transcript abundance of genes involved in the PGF2α synthetic cascade. Nelore heifers (N = 50) were subjected to a hormonal protocol for the synchronization of ovulation. Between days 14 and 23 after estrus, the area (cm2) and blood perfusion (%) of the corpus luteum (CL) and progesterone (P4) plasma concentrations were evaluated daily. On day 15, the heifers were assigned to the Control (2 mL of pure sesame oil, N = 21) or Estradiol group (1 mg of E2 diluted in 2 mL of sesame oil, N = 23). After the treatments at 0 h, uterine biopsies were collected at times 1.5 h (C1.5h, N = 8 and E1.5h, N = 10) or 3 h (C3h, N = 8 and E3h, N = 11); and blood samples were obtained from 0, 3, 4, 6 and 7 h for the measurement of 13,14-dihydro-15-keto-PGF2α (PGFM) concentrations by ELISA. Transcript abundance was determined by RT-qPCR and protein abundance of ESRβ and OXTR was determined by Western Blotting. The Estradiol group showed greater (P < 0.05) concentrations of PGFM at 6 and 7 h compared to the Control group. A progressive decrease in plasma P4 concentrations characterized a hastened functional luteolysis, followed by structural luteolysis in the Estradiol group (P < 0.05). Among the treatment groups, no significant difference was detected for the abundance of PRKCα, PRKCβ, AKR1B1, PTGS2 and ESRα transcripts (P > 0.05). Estradiol treatment decreased the abundance of PLA2G4A, AKR1C4, and ESRβ both 1.5h and 3h after treatment (P < 0.05). The relative expression of PGR and OXTR was greater in E3h compared to the C3h (P > 0.05). Protein abundance did not differ between treatment groups at either experimental times (P > 0.05). Overall, E2 promoted an increase in PGFM concentrations and the hastening of functional and structural luteolysis in Nelore heifers through the upregulation of PGR and OXTR, demonstrating for the first time that the expression of these receptors within 3 h after E2 stimulus was associated with triggering luteolysis in cattle.

Evaluation of the Reproductive Performance of Females of Anguilla anguilla Characterized by Different Levels of Silvering

The European eel, Anguilla anguilla (Linnaeus, 1758), is a species of high conservation and commercial value. Also, with a high aquacultural value, it was one of the most farmed species in Europe before its decline. Conservation measures for this species are currently being implemented, some of which are the release of adults to allow them to migrate to spawning grounds and artificial reproduction to minimise the impact of overfishing. Much progress has been made regarding the closing of the life cycle, but several problems remain to be solved, such as the weaning and growth of larvae. In this regard, the study of local populations and the identification of the best spawners could be a good way forward as it would help to identify spawners with high reproductive potential and good offspring quality. In this study, we compared the reproductive performance of female eels from migratory areas of the Northern Adriatic Sea at different maturation stages (10 pre-migrant stage; 10 migrant stage), treating both groups with the same hormonal protocol (weekly carp pituitary extract, injection of 17α,20β-Dihydroxy-4-pregnen-3-one at complete oocyte maturation). The research showed that eels at the beginning of metamorphosis (SI III), i.e., eels not yet ready to undertake migration, achieve reproductive performance equal to that of eels ready for migration (SI IV). Their performance was on par in both qualitative and quantitative terms. The optimal results in hatching (with values of 65.8 ± 3.2% for pre-migrant and 68.2 ± 4.1% for migrant) and survival rates (with value of 25.7 ± 5.4% pre-migrants; 27.2 ± 3.7% migrants), as well as the results about the time to reach full gonadal maturation, may have positive implications when considering release and restocking measures.

Plasma estradiol profile after administration of different types of estradiol esters in acyclic mares.

Although the use of different estradiol esters has been extensively studied in hormonal protocols in cows, such information is lacking in mares. The present study aimed to assess the effects of treatment with the same doses and administration frequency of estradiol cypionate, estradiol benzoate and 17β estradiol on plasma estradiol (E2) concentrations of acyclic mares and correlate the E2 profile to the endometrial edema score. Sixteen treatments were performed in 14 mares randomly divided into three groups: EB (n=5), EC (n=5) and 17β (n=6), receiving 10mg on day 0 (D0), 6mg on D1 and 4mg on D2 of estradiol benzoate, estradiol cypionate, and estradiol 17β, respectively. Blood samples, rectal palpations and ultrasound evaluations were performed once daily, starting before the first estradiol treatment (D0) until edema disappearance or D8. Moderate to high edema was observed in all groups 24h after the first estradiol administration. Edema persisted above score 2 until D7, D5 and D4 in groups EC, EB and 17β, respectively. Higher edema was found on D2 in EB group compared to 17β, on D6 and D7 in EC compared to 17β, and on D8 in EC compared to EB (p≤0.05). Maximum E2 concentrations were detected on D1 in groups: EB, showing a sharp decrease from D2 to D3 (p<0.0001); and 17β, where no differences were observed between treatment days (p≥0.05). In the EC group, maximum concentrations were observed on D2, which remained high from D2 to D4 compared to the other days (p<0.0001). Plasma concentration of E2 was higher in EB than the other groups on D0 and D1, and EB>EC>17β on D2. Plasma E2 concentrations and edema score were positively correlated, being moderate in groups EB and EC and weak in the 17β group. In conclusion, the most pronounced plasma E2 concentration was observed in EB group 24h after the administration of the first dose. Estradiol concentrations peaked 48h after EC administration, while a distinct peak was not observed in a 24h interval evaluation in the 17β group. Moreover, high edema does not necessarily reflect on high E2 concentrations in acyclic mares.

Fertility Augmentation of Non-Descript Delayed Pubertal Cattle Heifers through Mineral Mixture Supplementation and Hormonal Intervention

Normal productive and reproductive behavior in domestic animal is closely associated with interaction between hormonal and nutritional status of the animal system. Twenty-four non-descript delayed pubertal cattle of Rewa district, aged between 3-5 years were used to study the effect of dietary mineral mixture supplementation and double PG protocol on reproductive performance. Cows were randomly allocated into four equal groups (A, B, C &amp; D), comprising three treatment groups (n=6), and control (n=6) group. Control group was fed ration containing same CP and energy level according to the body weight. Group A (n=6) was fed ration containing 0% mineral mixture feeding in total per day. Group B (n=6) was fed ration containing mineral mixture 1 % of ration feeding in total per day diet. Group C (n=6) were subjected for double PG protocol and GnRH. Group D (n=6) was fed ration containing mineral mixture 1 % of ration and double PG protocol and GnRH. Group D has slightly more progesterone levels comparison to group C because of pregnancy in more cows. Plasma progesterone concentration of B, C and D Group, which supplemented with mineral mixture and hormonal protocol were significantly high. At 60-day Group A and C has similar values of progesterone. Group D has low Estrogen values due to more number or non-cyclic cows then other groups. Mineral concentrations were also significantly high in treatment groups comparatively. Pregnancy rate obtained in non-descript delayed pubertal heifers after artificial insemination was recorded as 83.33% in Group D, while it was 100% in all other three groups. Estrus submission rate is 33.33%, 50.00%, 66.66% and 83.33 % in all four groups, respectively. Accordingly reproductive efficiency calculated in experimental groups is 33.33, 50.00, 66.66 and 69.44, respectively. Combination of hormonal protocol with mineral mixture supplementation showed comparatively better result with respect to submission rate and reproductive efficiency.

Plasma estradiol profile after administration of different types of estradiol esters in acyclic mares.

Although the use of different estradiol esters has been studied extensively in hormonal protocols in cows, such information is lacking in mares. The present study aimed to assess the effects of treatment with the same doses and administration frequency of estradiol cypionate (EC), estradiol benzoate (EB) and 17β estradiol (17β) on plasma estradiol (E2) concentrations of acyclic mares and correlate the E2 profile to the endometrial edema score. Sixteen treatments were performed in 14 mares randomly divided into three groups: EB (n=5), EC (n=5) and 17β (n=6), receiving 10mg on day 0 (D0), 6mg on D1 and 4mg on D2 of estradiol benzoate (Sincrodiol®, Ouro Fino, Brazil), estradiol cypionate (E.C.P®, Zoetis, Brazil), and estradiol 17β (17βeta®, Botupharma, Brazil), respectively. Blood samples, rectal palpations and ultrasound evaluations were performed once daily, starting before the first estradiol treatment (D0) until edema disappearance or D8. Plasma E2 was quantified by radioimmunoassay. Endometrial edema was scored as: 0= lack of edema, 1=mild, 2=moderate, 3=high and 4=exaggerated. Mean estradiol plasma concentrations were analyzed by general linear model of variance with repeated measures. Median edema scores were compared by Kruskal Wallis followed by Mann Whitney tests while Spearman's correlation test was used to correlate E2 concentrations and edema score. Moderate to high edema was observed in all groups 24h after the first estradioladministration. Edema persisted above score 2 until D7, D5 and D4 in groups EC, EB and 17β, respectively. Higher edema was found on D2 in group EB compared to 17β, on D6 and D7 in group EC compared to 17β, and on D8 in group EC compared to EB (p≤0.05). Maximum E2 concentrations were detected on D1 in groups: EB (190±83.3 pg/mL), showing a sharp decrease from D2 to D3 (p<0.0001); and 17β (44.99±15.0 pg/mL), where no differences were observed between treatment days (p≥0.05). In the EC group, maximum concentrations were observed on D2 (81±43.8 pg/mL), which remained high from D2 to D4 compared to the other days (p<0.0001). Plasma concentration of E2 was higher in group EB than the other groups on D0 and D1, and EB>EC>17β on D2. Plasma E2 concentrations and edema scores were positively correlated, being moderate in groups EB and EC (EB: r=0.47; EC: r=0.45, p<0.01) and weak in the 17β group (r=0.39, p<0.0001). In conclusion, the most pronounced plasma E2 concentration was observed in group EB 24h after the administration of the first dose. Estradiol concentrations peaked 48h after EC administration, while a distinct peak was not observed in a 24h interval evaluation in the 17β group. Moreover, high edema does not necessarily reflect on high E2 concentrations in acyclic mares.

Reproductive response of crossbred Bos taurus x Bos indicus cows to biostimulation by pre-pubertal and pubertal teasers.

Although, the beneficial effect of biostimulation on reproduction has been reported, the influence of selectivity and social factors on the response to biostimulation has not received sufficient research attention in both, Bos indicus and Bos indicus influenced cattle. Moreover, "green and cheap" strategies to improve cattle reproduction are currently in demand while Bos indicus influenced cattle with inferior reproductive performance and farmers with economic limitations are common in tropical zones. Hence, to assess the reproductive response of crossbred taurus x indicus cows to biostimulation by pre-pubertal (PPM) or pubertal (PM) teasers males, two trials of two years each were conducted. Trial 1 n=187 cows (Year 1:85 cows exposed to PPM and Year 2:102 cows exposed to PM). Trial 2 n=196 cows (Year 1:101 cows exposed to PPM and Year 2:95 cows exposed to PM). The effect of exposing cows to PPM and PM on the intervals calving to first service (ICFS), calving to conception (ICC) and economic cost of days open (ECDO) was analyzed using Kruskal-Wallis ANOVA and the effect of exposing cows to PPM and to PM on reproductive status at 90d (RS90) and proportion of cows requiring hormonal protocols (PRH) was compared using χ2 analysis. Both, ICFS and ICC were shorter (P<0.0001) for PM-exposed females (96.12±4.1 and 110.93±2.9 d; respectively) than for those PPM-exposed (134.41±3.3 and 135.64±2.4 d; respectively). With RS90, more (P<0.0001) PM-exposed cows (50.7%) were pregnant than PPM-exposed cows (16.1%). The PRH was greater (P<0.0001) in PPM-exposed cows (79.0 %) compared to PM-exposed (27.9%). The ECDO was less (P<0.0001) in PM-exposed cows (US$ 142.9±3.8) than PPM-exposed (US$ 176.3±2.9). In conclusion, cows exposed to PM had shorter ICFS and ICC than cows exposed to PPM. More cows exposed to PM were pregnant after 90d and PRH was less than cows exposed to PPM. Cows exposed to PM had a reduced ECDO than those exposed to PPM.

Maximizing the Reproductive Efficiency of Cattle: A Review Benefits of Sexual Puberty Induction in Heifers Through Hormonal Protocols

Maximizing the Reproductive Efficiency of Cattle: A Review Benefits of Sexual Puberty Induction in Heifers Through Hormonal Protocols

Effects of early weaning on productive and reproductive performance of Nelore heifers

Abstract We aimed to evaluate the effects of early weaning on the productive and reproductive characteristics of Nelore heifer progeny. Ninety-five calves from primiparous (PRI) and multiparous (MUL) dams were assigned to one of two weaning strategies; 1) early weaning at 150 d (149 ± 1.97) of age (EW; n = 16 from PRI and 31 from MUL); or 2) conventional weaning at 240 d (247 ± 2.41) of age (CW; 16 from PRI and 32 from MUL). All heifers received ~5 g/kg of body weight (BW) of creep-feed as fed from 90 d of age until weaning. After weaning, each group of heifers was transferred to a Brachiaria spp. paddock and received 5 g/kg of BW of a protein-energy supplement until 12 mo of age. Then, heifers were confined and fed a diet with a ratio of 79:31 (corn silage: concentrate) for 4 mo, during which they were submitted to a hormonal protocol to induce puberty and timed artificial insemination (TAI). Reproductive tract score (RTS, 1 to 5 scale: 1 being infantile and 5 being cyclic) and endometrial thickness were determined at 12 mo of age, rump fat thickness (RFT), and BW every 28 ± 4 d through the breeding season, and plasma concentrations of IGF-I were evaluated at 12, 14, and 16 mo. At 15.6 mo of age heifers were submitted to a P4/E2 protocol for TAI at day 0 (D0), and a second TAI was performed at D22 in nonpregnant heifers. Ultrasound was used to determine the presence of corpus luteum on D10 and dominant follicle (DF) diameter and blood perfusion on D2 and D0. Data were analyzed using SAS by ANOVA or logistic regression. Though heifers from EW were lighter (P &amp;lt; 0.05) than CW at postweaning time points and CW presented a greater (P = 0.002) RFT than EW heifers from 11 to 15 mo, weaning strategy did not affect (P &amp;gt; 0.1) body condition score at TAI. Concentrations of IGF-I did not differ (P &amp;gt; 0.1) between heifers weaned at 150 and 240 d. The proportion of pubertal heifers, endometrium tone and thickness, and RTS at 16 mo did not differ (P &amp;gt; 0.1) between EW and CW groups. The diameter of DF on D2 and D0 and follicular blood perfusion on D0 were greater (P &amp;lt; 0.05) for heifers in the CW group than EW group, but P/AI at first and second TAI did not differ (P &amp;gt; 0.1) between groups. In conclusion, early weaning in Nelore heifers moderately reduces postweaning growth but does not affect puberty and reproductive performance before the breeding season when submitted to confinement.

Efficacy of Hormonal Protocols on Haematological and Micro-minerals Parameters in Postpartum Anestrus Cows

Thirty six post partum anestrus cows were selected for the present research work. Group I (n=12) were treated with CIDR based protocols and Group II (n=12) were administered Ovsynch protocol and Group III (n=12) was kept as a untreated control. In Group I, II and III the values of Hematological parameters like Hb (9.00±0.17, 9.15±0.15 and 8.65±0.30, 8.66±0.20, 8.73±0.20 and 8.25±0.20, 7.76±0.16, 7.69±0.32 and 8.18±0.18 g/dl) RBC (7.28±0.37, 9.15±0.15 and 8.65±0.30, 7.20±0.38, 8.73±0.20 and 8.25±0.33, 5.77±0.32, 7.69±0.32 and 8.18±0.18 x1012/l) and TLC 10.36±0.26, 10.49±0.25 and 9.77±0.40, 9.67±0.28, 9.90±0.47 and 8.08±0.57, 8.29±0.53, 7.98±0.54 and 8.63±0.44 x109/l) on Day 0, 7 and 25 were recorded in Group I, II and III, respectively. Microminerals parameters (μg/dl) like Iron (147.9±4.44, 147.9±4.44 and 150.1±7.84, 143.4±4.5, 158.2±4.65 and 149.4±7.71, 118.6±3.23, 118.6±3.12 and 118.4±3.04) Cobalt (1.8±0.14, 2.2±0.10 and 1.99±0.11, 1.7±0.10, 2.1±0.08 and 1.74±0.13, 1.6±0.12, 1.5±0.10 and 1.6±0.11) Copper (0.65±0.02, 0.78±0.03 and 0.71±0.04, 0.63±0.01, 0.77±0.03 and 0.69±0.03, 0.64±0.02, 0.63±0.02 and 0.65±0.02) and Zinc (87.6±1.18, 104.9±2.00 and 96.4±3.27, 86.7±1.22, 104.7±2.02 and 93.6±2.51, 85.5±1.03, 85.6±1.02 and 86.5±0.92) on Day 0, 7 and 25 were recorded in Group I, II and III, respectively. It can be concluded that the use of different hormonal protocols in postpartum anestrus cows has shown different effects on haematological and micro-minerals parameters.

Improved reproductive performance in anestrous crossbred Jersey cattle by area specific mineral mixture and hormonal protocol

Improved reproductive performance in anestrous crossbred Jersey cattle by area specific mineral mixture and hormonal protocol