Heatsynch Protocol Research Articles

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.

Blood Plasma Biochemical Changes and Conception Rate in Anoestrus Buffaloes Treated with Various Hormone Protocols

To study certain blood biochemical parameters (total cholesterol, total protein, calcium and inorganic phosphorus) at various periods of treatment. Total 40 anestrous buffalo heifers with history of anoestrus were selected from the semi-arid area of Banaskanth and randomly divided into four equal groups. (1)Group-I:Heatsynch protocol (n=10), (2)Group-II:Ovsynch protocol(n=10), (3)Group-III: Doublesynch protocol (n=10) and (4)Group-IV: Control(n=10) followed by fixed time artificial insemination in treated buffalo heifers and insemination at spontaneous estrus in buffalo heifers of group-IV. The overall conception rate following 3 consecution services was maximum in Group II (50%) followed by Group III (40%), Group I (30%) and Group IV (30%). The blood plasma was collected at the time of initiation of treatment (P1), at the time of inj. PGF2α (P2), at the time of 1st FTAI (P3) and day 21st post insemination (P4) for the estimation of biochemical parameters. The blood biochemical profiles include total protein (range: 4.54± 0.19 to 6.11± 0.52 g/dl) which in all group did not show any significant difference during the different period but significant (P<0.05) difference between the groups was noticed. Similarly calcium and phosphorus found ranging between 5.73± 0.20 to 9.53± 0.95 mg/dl and 5.46± 0.22 to 6.95± 0.30 mg/dl, respectively in all four groups. The cholesterol estimated values (range: 34.12 ± 1.75 to 41.97± 2.43 mg/dl) were found not-significantly varying between the groups as well as among the different periods. Heatsynch, Ovsynch and Doublesynch protocol can be successfully used for the induction of estrus in true anoestrus buffalo heifers with Better conception rate would be achieved following Ovsynch protocol in buffalo heifers.

Presynch-Heatsynch: A New Approach to Improve Ovarian and Fertility Responses in Water Buffalo (Bubalus bubalis)

Background: Standard estrus synchronization regimens resulted in variable outcomes in buffaloes. The present study evaluated ovarian and fertility responses following presynchronization in Heatsynch protocol administered in postpartum buffaloes. Methods: In group-I (Presynch-Heatsynch group, n = 30), PGF2α was administered on days -14 and -2. Then, GnRH analogue, PGF2α (Cloprostenol) and Estradiol benzoate were administered on day 0, 7 and 8, respectively followed by fixed-time artificial insemination (FTAI) 48 hours later. In group-II (Heatsynch group, n = 30), rest protocol was same, except that first two PGF2α injections were not administered. Result: The progesterone concentrations differed (P less than 0.01) between the two groups on days -2, 0 and 7. Post-treatment, progesterone profiles were also higher in pregnant compared to non-pregnant buffaloes in both the groups except on day 10. CL diameter differed (P less than 0.01) between groups on days -2, 0 and 7. It was larger in pregnant than non-pregnant buffaloes on day 7 in both the groups. Dominant follicle diameter remained larger on days -2, 0 and 8 in group-I than -II. Buffaloes getting pregnant had a larger (P less than 0.01) dominant follicle size on the day of FTAI in group-I than of group-II. Ovulatory response of 93.33 and 90.00% was observed in group-I and II. The conception rate was higher (66.66 vs. 40.00%; P less than 0.05) in group-I than Group-II. Presynchronization improved reproductive efficiency in Heatsynch treatment and may aid for better fertility in buffaloes.

The effect of heatsynch protocol on repeat breeding dairy cows

The aim of this study was to know the incidence of repeat breeding in dairy cows and to know the effectiveness of Heatsynch protocol on dairy repeat breeding cows. The study was conducted in two stages. The first stage, all dairy cows were recorded and clinically examined through palpation per rectum and for their reproductive statuses. Parameter measured in the study was the incidence of repeat breeding. The second stage of the study was that the repeat breeder cows subjected to Heatsynch protocol for estrus induction. The protocol was GnRH injection on day-0, followed by PGF2α, estradiol injections on day-7 and day-8, respectively, and inseminated artificially on day-9. The results of the study indicated that the incidence of repeat breeding was 41.6%. The Heatsynch protocol was successfully increase the number of pregnant repeat breeder cows; 75%, higher compared to untreated repeat breeder cows; 20%. It can be concluded that high incidence of repeat breeding in dairy cows. Heatsynch protocol can be used to treat repeat breeder cows and improve the reproductive efficiency.

Efforts to improve reproductive efficiency in dairy heifers experiencing delayed puberty using heatsynch protocol

The aim of this study was to find out the application of Heatsynch protocol in overcome the delayed puberty of dairy heifers that suffered from infertility. This study was conducted at small dairy farms in Sub-district of Cendana, Enrekang Regency, Indonesia. The study was conducted in two stages. In the first stage, a total of 50 dairy heifers were used to determine the percentage of heifers that experienced delay in puberty. In the second stage, 20 dairy heifers with delayed puberty were divided into two groups. The first group, 10 dairy heifers were treated with Heatsynch and the other 10 dairy heifers were used as negative control (without Heatsynch). For control positive, 10 dairy heifers that did not suffered from delayed puberty were used. In Heatsynch treated dairy heifers, GnRH were injected on day-0, followed by PGF2α, estradiol injections on day-7 and day-8, respectively, and inseminated artificially on day-9. The results of this study showed that the percentage of dairy heifers that experienced in delayed puberty was 44%. The mean age at first pregnant after treated with Heatsynch was 545 days, shorter than those heifers in control negative (644 days). The percentage of dairy heifers become pregnant after treating with Heatsynch was 80%, higher than those untreated delayed puberty heifers (50%). It can be concluded that the incidence of delayed puberty in dairy heifers was still high. Heatsynch protocol can be one way that can be used to overcome the problem of delayed puberty in dairy heifers and to improve reproductive efficiency.

The effectiveness of Heatsynch protocol in dairy cows with abnormalities of reproductive organ

The aim of this study was to determine the incidence of abnormalities of reproductive organs, and to determine the effectiveness of Heatsynchprotocol in dairy cows that suffered from abnormalities of reproductive organs. This study was conducted in smallholder dairy farms in Panette, Cendana Sub-district, Enrekang Regency and the study was conducted in two stages. The first stage; a total of 77 dairy cows were used to determine the incidence of reproductive organs abnormalities. The second stage; a total of 20 dairy cows that suffered from reproductive organs abnormalities were divided into two groups. The first 10 dairy cows were treated with Heatsynch, and the other 10 dairy cows were used as a negative control (without Heatsynch treatment). For positive control, 10 dairy cows that did not suffered from abnormalities of reproduction organs were used. The results of this study showed that the incidence of reproductive organs abnormalities was 36.4% and the highest of abnormalities was uterine disorders at 26%. The percentage of cows suffered from reproductive organs abnormalities that became pregnant after treated with Heatsynch was 60%, while none cows become pregnant without treatment. The average interval from calving to pregnancy in Heatsynch group was 512 days, and in control negative cows, none become pregnant up to 557 days after calving. It can be concluded that the incidence of abnormalities of reproductive organs in dairy cattle was still high. The Heatsynchprotocol can improve the abnormalities of the reproductive organs in the dairy cows and improve reproductive efficiency by increase the pregnancy rate and shortening calving interval.

Efficacy of different estrus synchronization protocols in repeat breeder cows

The work was conducted in 272 repeat breeder cows diagnosed with functional form of infertility, i.e. luteal insufficiency and ovulatory defects. The objective of present study was to evaluate the efficacy of synchronization protocols in functionally infertile repeat breeder cows. These cows were divided into 4 treatment, viz. Ovsynch, Ov-cosynch, Doublesynch, Heatsynch and one control group. The overall conception rate of Ovsynch treatment protocol was significantly higher than control cows. Similarly, the mean diameter of dominant follicle in cows treated with Ovsynch protocol was significantly higher than cows treated with Doublesynch and Heatsynch protocols. Also, the mean diameter of dominant follicle prior to artificial insemination in the cows treated with Ovsynch protocol was significantly higher in comparison to control cows. In conclusion, Ovsynch protocol fared better in terms of conception in repeat breeder cows.

Insulin effect during a Heatsynch protocol in dairy cows

ABSTRACT: The objective of this study was to evaluate the effect of exogenous insulin administration on follicular growth, estrus presentation and conception rate during a protocol of ovulation synchronization. Dairy cows were subjected to the Heatsynch protocol, with the insertion of an intravaginal device containing 1.9 g of progesterone (CIDR) and an intramuscular injection containing 2.5 mg of GnRH on day 0. On day 7, the CIDR was removed and subjects were given 12.5 mg of dinoprost. Also on day 7, Insulin Group (IG, n = 21) animals received a subcutaneous injection containing 0.25 IU / kg of recombinant human insulin and the control group (CG, n = 25) received a 0.9% NaCl injection. On day 8, an injection of 0.5 mg of estradiol cypionate was administered to all cows. Animals were inseminated 12 hours after estrus presentation or at day 10 at fixed time. Follicular development was evaluated on days 7, 9, and 10 using transrectal ultrasonography, estrus presentation was observed between days 8 and 10, and conception rate was evaluated 30 days after AI. There were no differences in growth rate, follicular diameter, estrus presentation, and conception rate. Therefore, application of a single dose of insulin does not promoted an increase in follicular size, estrus presentation and conception rate in dairy cows.

Serum Macro-Minerals Profile and Conception Rate following Heatsynch and Heatsynch + PRID Protocols in Subestrus Surti Buffaloes

A study was carried out to interpret the first and second service conception rate along with serum macro-minerals profile for Heatsynch (T1) and Heatsynch + PRID (T2) protocols with fix timed AI in subestrus Surti buffaloes (n=6 each), keeping one group as untreated control (T3). In Heatsynch protocol, buffaloes were administered i.m. with Inj. Busereline acetate 10 μg on day 0, Inj. Cloprostenol sodium 500 μg on day 7 and Inj. oestradiol benzoate (EB) 0.5 mg on day 8 followed by FTAIs twice on day 10, while in Heatsynch + PRID protocol the buffaloes were inserted with PRID (0.96 g of progesterone) intravaginally for 7 days together with above Heatsynch protocol. Blood samples were collected aseptically in vaccutainers from all these animals on day 0 (prior to treatment), day 4 (during treatment), day 8 (after PGF2α inj.), day of induced estrus/FTAI and on day 28 (post-treatment, day 18 post-AI), and serum samples were stored at –20°C until analyzed. The buffaloes that became pregnant at 1st service (FTAI) in the treatment group T1 and T2 were 50.00 (3/6) and 66.66 (4/6) % and at 2nd cycle 100.00 (3/3) and 50.00 (1/2) %, respectively. The corresponding conception rates for control group T3 were 33.33 (2/6) and 50.00 (2/4) %. The overall pooled CRs of 2 cycles achieved in groups T1, T2 and T3 were 100.00 (6/6), 83.33 (5/6) and 66.66 (4/6) %, respectively. The overall mean serum calcium, phosphorus and magnesium values did not differ significantly (p>0.05) among T1, T2 and T3 groups at any day or within group between different sampling intervals. Heatsynch alone was better and economic over other groups in managing subestrus buffaloes.

Estrus Induction Response Vis-a-Vis Serum Progesterone and estradiol 17-β Profile in Postpartum Subestrus Surti Buffaloes Primed with Heatsynch Alone and Heatsynch plus PRID Protocol

This study was conducted on 18 subestrus Surti buffaloes at University farm to estimate steroid hormone values before, during and after use of Heatsynch (T1) and Heatsynch+PRID (T2) protocols. In the Heatsynch protocol (n=6), buffaloes were administered intramuscularly with inj. Busereline - GnRH analogue on day 0, inj. Cloprostenol sodium-PGF2α analogue on day 7 and inj. Estradiol Benzoate (EB-) on day 8. In the Heatsynch+PRID protocol (n=6), PRID was inserted intra-vaginally and kept in situ for 7 days with inj. Buserelineon day 0. The PRID was removed on day 7 together with inj. of Cloprostenol and inj. EB was administered on day 8. FTAI was done twice on day 10 in both the groups. No treatment was given to control (n=6) group (T3). The estrus response was 100% in all three groups, but the conception rate at first cycle/service was 50.00, 66.66 and 33.33%, respectively, in three groups. The mean plasma progesterone concentrations were significantly lower on day of estrus (0.26±0.05, 0.63±0.07and 0.58±0.08 ng/ml in T1, T2 and T3 respectively) as compared to the corresponding values on day 0, 4, 8 of treatment and 18 post-AI in all the three groups.The mean values of estradiol-17β markedly increased (p less than 0.01) on the day of estrus in treatment groups T1 and T2 (43.45±1.42 pg/ml and 42.86±1.53 pg/ml) than control group T3 (35.74±0.63 pg/ml) and thereafter markedly decreased at 18th day post-AI in all the groups (17.93±4.49; 16.34±2.14; 25.52±3.10 pg/ml) with non-significant difference.

Ovulatory and fertility response using modified Heatsynch and Ovsynch protocols in the anovular Murrah buffalo (Bubalus bubalis)

We studied the effect of modified Heatsynch and Ovsynch protocols on the ovulatory response (OR), estrus induction rate (EIR) and conception rate (CR) in the anovular postpartum Murrah buffalo (n = 35). In the modified Heatsynch protocol (Group I; n = 12), buffaloes were given two GnRH at 2 h interval on treatment day 0, PGF (PGF2α) on day 7 and estradiol (E2) 1 mg on day 8. Two FTAI were done at 20 h intervals after E2 administration. In the modified Ovsynch protocol (Group II; n = 15), GnRH was given on day 0, 7 and 16 with a PGF on day 14. Two FTAI were done; one at last GnRH and the other 20 h later. Group III served as untreated negative control (n = 8). During the treatment, ovarian changes were monitored by transrectal ultrasonography and plasma progesterone (P4) and E2. Administration of two GnRH at 2 h interval neither increased the OR nor strengthened the subsequent P4 priming. Interestingly, in group I, none of the buffalo ovulated to E2 though the EIR was 100% indicating the occurrence of behavioral, but not ovulatory estrus. Administration of GnRH 7 day prior to the commencement of Ovsynch protocol (Group II) did not improve the CR (21.4%), though the OR was 71.4%. No significant difference was found in the diameter of largest follicle between the ovulated and non-ovulated buffalo in response to GnRH suggesting that follicle of ≥9.5 mm is necessary but not sufficient to induce ovulation in the anovular buffalo. In both the protocols, the plasma P4 was higher on day 7 in those buffaloes that ovulated to GnRH. Buffaloes treated with modified Ovsynch regimens were 5.27 times more likely to become pregnant than modified Heatsynch protocol. It is concluded that modified Ovsynch protocol is superior to modified Heatsynch protocol in terms of OR and CR.

A Short Presynchronization with PGF2α and GnRH Improves Ovarian Response and Fertility in Lactating Holstein Cows Subjected to a Heatsynch Protocol

Abstract The objective of this study was to assess the efficacy of a single injection of Prostaglandin F2α (PGF2α) combined with or without GnRH before initiation of a Heatsynch protocol (GnRH-7d- PGF2α-2d-EB-1d-AI) on ovarian response and fertility in lactating Holstein cows. A total of 252 cows with a corpus luteum (CL; ≥10 mm) were assigned to one of three synchronization groups; 1 - Control (n=84), cows received two injections of PGF2α 14 days apart; 2 - Heatsynch with GnRH (PGH, n=88) the cows received PGF2α followed by GnRH four days later and then a Heatsynch protocol was initiated eight days after GnRH treatment; and 3 - Heatsynch without GnRH (PH, n=80) cows received a single injection of PGF2α followed by a Heatsynch protocol initiated 12 days after PGF2α. Cows detected in estrus were inseminated approximately 12 h after onset of estrus. Ovarian response and pregnancy diagnosis were determined by ultrasonography during the synchronization protocol and 30 days after AI, respectively. Results showed the percentage of cows with plasma P4≤0.4 ng/mL at AI were greater in PGH group compared to other groups (90.3 vs. 75.0%, P=0.03). The percentage of cows that ovulated in response to the GnRH injection of Heatsynch was affected (P<0.01) by synchronization protocol, because PGH cows were more likely to ovulate (77.2%) than PH (56.0%) cows. The proportion of cows displaying estrus was greater in PGH (70.4%) and PH (72.5%) groups compared with control (47.0%, P=0.04). Percentage of cows pregnant at 30 days after AI was (P=0.01) affected by synchronization treatment and was greater in PGH (45.16%) compared to control (25.0%) and PH (34.48%) groups. In summary, a short presynchronization that includes an injection of PGF2α and four days later GnRH increased fertility in Holstein cows subjected to a Heatsynch protocol. The enhanced fertility was due to a greater ovulatory response to GnRH of Heatsynch, more adequate plasma P4 concentrations during follicle development and a greater luteal regression following PGF2α prior to AI.

Effect of Various Ovulation Synchronization Protocols on Estrus Response, Conception Rate and Blood Biochemical Profile in Anoestrus Buffaloes

This study evaluated the fertility response and plasma profile of biochemical and mineral constituents in 46 postpartum anoestrus (>90 days) buffaloes treated under field conditions with TriU-B/PRID, Ovsynch and Heatsynch protocols (n=12 each), keeping untreated anoestrus control (n=10) and normal cyclic control (n=10) groups. The estrus induction response with 3 treatment protocols was 83.33, 83.33 and 91.66 % respectively within 2-3 days of PGF 2 α injection. The conception rates (CRs) obtained at induced estrus in buffaloes under TriU-B, Ovsynch and Heatsynch protocols were 25.00, 33.33 and 25.00 %, and those of overall three cycles’ 50.00, 58.33 and 50.00 %, respectively, which were at par with normal cyclic control group (CR at first cycle 30.00 & overall of 3 cycles 50.00 %). Among untreated anoestrus control group, only two buffaloes (20%) exhibited estrus and conceived over 90 days follow up. The overall pooled mean plasma total cholesterol concentrations (mg/dl) in anoestrus buffaloes under TriU-B and in normal cyclic control group were the same (166.70±5.28 and 165.18±6.37) and significantly (P<0.01) higher than in Ovsynch (131.54±3.71) and lower than in Heatsynch (186.14±5.69) group. The value for total protein (g/dl) was significantly (P<0.05) lower in TriU-B (7.27±0.08) followed by other two groups (7.62±0.07 & 7.44±0.07) and highest in normal control group (7.98±0.10). The calcium was significantly higher (P<0.05) in Ovsynch (10.41±0.07 mg/dl) than other 3 groups (8.82±0.11 to 9.09±0.09 mg/dl), while inorganic phosphorus (3.99±0.10 to 4.29±0.13 mg/dl) did not vary between groups. Normal cyclic control buffaloes had significantly higher protein and lower calcium levels than in most treatment groups. The conceived buffaloes had apparently higher values of total cholesterol and protein as compared to non-conceived ones in all groups. In general, Ovsynch protocol was the best followed by TriU-B and Heatsynch for induction of estrus and improvement of fertility in anoestrus buffaloes.

Effect of GnRH or Estradiol Benzoate on Reproductive Traits during a Heatsynch Protocol in Dairy Cows

Background: Milk production of cows is closely correlated with its reproductive efficiency. One of the several factors influencing the dairy efficiency is the decline in fertility of the cows/heifers. Use of hormonal protocol are often used to improve the fertility of the recipients. Several programs are available to inseminate dairy cows, with variation in the use of different types of hormones, time of use and range of duration period, as well as the time of AI. The objective of this study was to evaluate the efficiency of follicular wave emergence induction of estradiol benzoate in comparison to GnRH in a Heatsynch protocol and its influence on reproductive parameters.Materials, Methods &amp; Results: In this study were used primiparous and multiparous Holstein cows (n = 325). Animals were divided randomly into two different treatments according with the hormone used to induce follicular wave emergence (D0). The GnRH group (n = 167), was given 25 mg, while in the EB group (n = 158) was used 2 mg. At same day, were inserted, a controlled internal drug-releasing containing 1.9 g of progesterone CIDR®. On day 7, CIDR was removed and cows were given 25 mg luteinizing hormone followed by an injection of 1 mg Inducer Ovulation at day 8. Cows were then observed for signs of estrus for at least two hours (twice daily at 7 am and 6 pm) for three days following CIDR® removal. Cows detected in estrus were inseminated 12 h later the estrus detection. Pregnancy status was determined by ultrasonography at 30 ± 5 d and 60 ± 5 d after AI. A single technician was responsible for the estrus detection and inseminations. A single technician was responsible for the estrus detection and inseminations. Ultrassonographic examinations with ultrasound, transrectal linear probe of 5 MHz, were performed for the diagnosis of pregnancy at 30 and 60 days after artificial insemination. Binomially distributed data, such as, estrous response, conception rate, pregnancy rate and pregnancy losses, were analyzed by Chi-square test. Pregnancy rates at 30-35 days and 60-65 days as well as pregnancy losses were considered in the model for the effect of parity (primiparous vs. multiparous) and the group of estrus behavior during the Heatsynch protocol. Conception rate was similar between GnRH (36.1%, 57/158) and EB (37.7%, 63/167) treatments. Cows showing estrus signs after CIDR removed were 71.9% in GnRH and 62% in EB group (P = 0.05). Embryonic losses were different (P = 0.03) according to groups of cows showing estrus signals or not.Discussion: Our results demonstrate that conception rates are not affected by using either EB or GnRH at the beginning of the Heatsynch protocol. Therefore, the EB can be an alternative choice to GnRH at Heatsynch beginning. Similar results were found by autor in dairy cows, once it was also observed that there is no difference in conception rate in two TAI protocols using either GnRH or EB. In Heatsynch protocols the increase in estrus detection are a key factor to increase fertility in lactating dairy cows. It can be explained once animals in regular estrous cycle have a palpable corpus luteum and circulating progesterone concentration higher than 1 ng/mL which leads than to enhance pregnancy ratios. The use of BE at the time of CIDR insertion in TAI protocols for dairy cattle proved to be an alternative to GnRH considering conception rates. Therefore, the use of BE at the time of CIDR insertion in a Heatsynch protocol in dairy cattle proved to be an alternative to GnRH which can be an important tool to increase the TAI utilization by farmers. Furthermore, in Heatsynch protocol cows showing estrus have pregnancy rates improved and lower pregnancy losses.

Comparison of endocrine changes, timing of ovulations, ovarian follicular growth, and efficacy associated with Estradoublesynch and Heatsynch protocols in Murrah buffalo cows (Bubalus bubalis)

Poor estrus expression and the difficulty encountered in predicting the time of ovulation compromise the reproductive efficiency of Murrah buffalo cows. Synchronization of ovulation and timed artificial insemination are able to precisely control the time of ovulation and thus avoid the need for estrus detection. Recently, the Estradoublesynch protocol (administration of a PGF2α injection 2 days before Heatsynch protocol; GnRH 0, PGF2α 7, estradiol benzoate [EB] 8) was developed that precisely synchronized ovulation twice, i.e., after GnRH and EB injections and resulted in satisfactory pregnancy rates in Murrah buffaloes. The present study was conducted on 104 cycling and 31 anestrus buffaloes to compare (1) the endocrine changes, timing of ovulations, ovarian follicular growth, and efficacy of Estradoublesynch and Heatsynch protocols in cycling and (2) the efficacy of Estradoublesynch and Heatsynch protocols for the improvement of fertility in cycling and anestrus Murrah buffalo cows. Ovulation was confirmed after all GnRH and EB treatments by ultrasonographic examination at 2-hour intervals. Plasma progesterone and total estrogen concentrations were determined in blood samples collected at daily intervals, beginning 2 days before the onset of protocols until the day of second ovulation detection. Ovulatory follicle size was measured by ultrasonography at six time points (first PGF2α administration of Estradoublesynch protocol every 2 days before the onset of Heatsynch protocol, GnRH administration of both protocols, 2 hours before ovulation detection after GnRH administration of both protocols, second PGF2α injection of Estradoublesynch protocol, PGF2α injection of Heatsynch protocol, EB injection of both protocols and, 2 hours before ovulation detection after EB administration of both protocols). Plasma LH, total estrogen, and progesterone concentrations were determined in blood samples collected at 30-minute intervals for 8 hours, beginning GnRH and EB injections, and thereafter at 2-hour intervals until 2 hours after the detection of ovulation. The first ovulatory rate was significantly higher (P < 0.05) in the Estradoublesynch protocol (84.6%) than that in the Heatsynch protocol (36.4%). The first LH peak concentration (74.6 ± 10.4 ng/mL) in the Estradoublesynch protocol was significantly higher (P < 0.05) than that of the Heatsynch protocol (55.3 ± 7.4 ng/mL). In Estradoublesynch protocol, the total estrogen concentration gradually increased from the day of GnRH administration coinciding with LH peak, and then gradually declined to the basal level until the time of ovulation detection. However, in Heatsynch protocol, the gradual increase in total estrogen concentration after GnRH administration was observed only in those buffalo cows, which responded to treatment with ovulation. In both Estradoublesynch and Heatsynch protocols, ovulatory follicle size increased by treatment with GnRH and EB until the detection of ovulation. The pregnancy rate after the Estradoublesynch protocol (60.0%) was significantly higher (P < 0.05) than that achieved after the Heatsynch protocol (32.5%). Satisfactory success rate using the Estradoublesynch protocol was attributed to the higher release of LH after treatment with GnRH, leading to ovulation in most of the animals and hence creating the optimum follicular size at EB injection for ovulation and pregnancy to occur.

Evaluation of the Heatsynch protocol in Murrah buffaloes (Bubalus bubalis) during hot summer season

The objective of this study was to evaluate the effect of the Heatynch protocol on plasma estrogen concentration in Murrah buffaloes and to evaluate if the Heatsynch protocol induces estrus in Murrah buffaloes. All treated animals responded to the treatment by displaying obvious signs of estrus. The mean plasma estrogen concentration among the individual buffalo was 191.9 ± 68.3 pg / ml after Estradiol benzoate (EB) injection. The plasma progesterone profile of these animals indicated that out of 16 animals 8 animals were acyclic before Heatsynch treatment (8/16) as plasma progesterone concentrations in these animals were basal (<0.24±0.01 ng/ml) for most of the sampling period during the course of treatment. Following Heatsynch treatment only two buffalo out of sixteen were acyclic (2/16) on the basis of their plasma progesterone profile. These results indicated that Heatsynch protocol is useful in inducing cyclicity in acyclic buffaloes. The seven buffalo out of sixteen (7/16) were conceived after treatment with Heatsynch protocol in summer. So, the treatment might have potential field application value to overcome poor estrus symptoms in summer.

Comparison between two progesterone sources and two oestradiol formulations in a Heatsynch protocol for postpartum cycling dairy cows in pasture

To compare an injectable progesterone (MAD-4) with an intravaginal device (IPD), and natural O17 with synthetic oestradiol (OB) in a synchronisation protocol, 51 cows were divided into four groups. Each group was treated with one of the two sources of progesterone and one of the two oestradiol formulations. Oestrus behaviour, follicle diameter, and pregnancy rates were evaluated. Oestrus behaviour (p = 0.902), numbers of cows in oestrus (p = 0.917), follicle diameter (p = 0.416), and pregnancy rates (p = 0.873) were similar among the four groups. More cows in the group treated with the IPD and OB scored > 200 oestrus behaviour points compared to the other groups (p = 0.038). A longer interval between the end of treatment and oestrus was observed among cows treated with MAD-4 than cows given the IPD (p = 0.030), but no differences were found between animals receiving the two oestradiol formulations (OB and O17). While the use of MAD-4 requires further testing, similar responses to natural oestradiol observed in the present study could allow the use of this formulation in reproductive protocols because it is not associated with the potential human health risks of OB.

Effect of estrus synchronization protocols on plasma progesterone profile and fertility in postpartum anestrous Kankrej cows

The study was aimed at induction/synchronization of estrus in postpartum anestrous Kankrej cows of zebu cattle maintained at an organized farm. The study included use of different hormone protocols, viz., Ovsynch, CIDR (controlled internal drug release), Ovsynch plus CIDR, and Heatsynch with estimation of plasma progesterone on days 0, 7, 9/11 (artificial insemination--AI) and on day 20 post-AI following fixed time insemination. Thirty selected anestrous animals were divided into five equal groups (four treatment and one control), and the findings were compared with the normal cyclic control group of six cows. All the protocols were initiated in cows with postpartum anestrous period of more than 4 months, considering the day of first GnRH injection or CIDR insertion as day 0. The animals were bred by fixed time artificial insemination. Pregnancy was confirmed per rectum on day 60 post-AI in non-return cases. The conception rates at induced/first heat in Ovsynch, CIDR, Ovsynch + CIDR, and Heatsynch protocols were 33.33, 66.66, 50.00 and 16.67%, respectively. The corresponding overall conception rates of three cycles post-treatment were 50.00% (3/6), 100.00% (6/6), 66.66% (4/6), and 50.00% (3/6). In normal cyclic and anestrous control groups, the pooled pregnancy rates were 83.33% (5/6) and 16.67% (1/6), respectively. The pooled mean plasma progesterone (nanograms per milliliter) concentrations were significantly (P < 0.05) higher on day 7 in Ovsynch (5.727 ± 1.26), CIDR (4.37 ± 0.66), Ovsynch plus CIDR (3.55 ± 0.34), and Heatsynch (5.92 ± 1.11) protocols as compared with their corresponding values obtained on days 0, 9/11 (AI), and on day 20 post-AI. In anestrous control group, the mean progesterone concentration at the beginning of experiment was 0.67 ± 0.33 ng/ml, which was at par with values of all other groups. The overall plasma progesterone levels on the day of initiating treatment were low in all groups, with smooth small inactive ovaries palpated per rectum twice at 10 days interval, suggesting that most of the animals used in the study were in anestrous phase. Mean (± SE) values of plasma progesterone (nanograms per milliliter) on day 20 post-AI were higher in conceived cows than the non-conceived cows of all the groups, but differed significantly (P < 0.05) only in normal cyclic group. These results suggest that use of different hormone protocols particularly Ovsynch, CIDR, and Ovsynch + CIDR may serve as an excellent tool for induction and synchronization of estrus and improvement of conception rate in postpartum anestrous Kankrej cows.

Comparison in Effect of Heatsynch with Heat Detection Aids and CIDR‐Heatsynch in Dairy Heifers

The objective of the present study was to determine whether oestrous detection with the help of oestrous detection aids during the Heatsynch without timed AI protocol is equally effective with the progesterone-combined protocol in dairy heifers. A total of 148 heifers were randomly assigned to one of the two groups. A group of heifers treated with Heatsynch with heat detection aids (n = 72) received GnRH on day 0, prostaglandin F(2alpha) (PGF(2alpha)) on day 7 and oestradiol benzoate (EB) on day 8, while in controlled internal drug release (CIDR)-Heatsynch group (n = 76), CIDR was included during a period from GnRH to PGF(2alpha). Heifers were checked for oestrus twice daily, i.e. from 09:00 to 10:00 hours and from 15:00 to 16:00 hours starting on day 2 for Heatsynch group and on day 8 in CIDR-Heatsynch group, and continued up to day 12. KAMAR heat mount detector (KAMAR Inc., Steamboat Springs, CO, USA) and ALL-WEATHER PAINTSTIK (LA-CO Industries Inc., Elk Grove Village, IL, USA) were used as heat detection aids. AI was conducted within 1 h after confirming oestrus in 72 heifers, while 19 animals were transferred with embryo 7 days after oestrus according to the request of the owners. Premature oestrus before PGF(2alpha) injection occurred in 18% of Heatsynch group. Of 13 heifers which showed premature oestrus, six were inseminated and two of them conceived. Oestrus detection rate within 12 days after initiation of the protocols did not differ between the two groups (94% vs 95%). There was no difference in the conception rate after first AI (including heifers that were inseminated before PGF(2alpha) injection) and embryo transfer between Heatsynch with heat detection aids and CIDR-Heatsynch groups (36% vs 44% and 70% vs 56%). It is concluded that the use of heat detection aids to monitor the occurrence of premature oestrus prior to PGF(2alpha) injection in Heatsynch protocol in dairy heifers was equally effective to the inclusion of CIDR.

Redução da primeira dose de GnRH em vacas holandesas de alta produção sincronizadas com Ovsynch ou Heatsynch

O objetivo desse estudo foi avaliar o efeito da redução da primeira dose de GnRH (10 vs 20 µg) e do tipo de protocolo de sincronização para a IATF (Ovsynch e Heatsynch) na taxa de prenhez de vacas holandesas de alta produção sincronizadas para IATF (n = 581). Os animais foram distribuídos entre os tratamentos e alocados em arranjo fatorial 2x2, sendo: Trat 1- Ovsynch (20 µg GnRH no D0; PGF no D7; 10 µg GnRH no D9 e IATF no D10; n = 141), Trat 2- ½ Ovsynch (10 µg GnRH no D0; PGF no D7; 10 µg GnRH no D9 e IATF no D10; n = 159), Trat 3- Heatsynch (20 µg GnRH no D0; PGF no D7; 1 mg BE no D8 e IATF no D10; n = 147) e Trat 4- ½ Heatsynch (10 µg GnRH no D0; PGF no D7; 1 mg BE no D8 e IATF no D10; n = 134). O Grupo Ovsynch (Trat 1 e 2) apresentou maior taxa de prenhez que o grupo Heatsynch (Trat 3 e 4) aos 28 dias (45,7% (137/300) e 39,9% (112/281), respectivamente; P = 0,07) e aos 56 dias de gestação (41,0% (123/300) e 34,2% (96/281), respectivamente; P = 0,06). A dose de GnRH, não influenciou (P &gt;; 0.10)a taxa de prenhez aos 28 dias (44,4% (128/288) vs 41,3% (121/293); P = 0,50) e aos 56 dias (38,2% (110/288) vs 37,2% (109/293); P = 0,68) entre os grupos tratados com 10 µg ou 20 µg de acetato de buserelina. As perdas gestacionais (ente 28 e 56 dias) nγo diferiram entre os protocolos para IATF e dose de GnRH (P &gt;; 0,10). Conclui-se que, protocolo Ovsynch apresentou maior taxa de prenhez à IATF que o Heatsynch e a administração de 10 µg de Acetato de Buserelina no início dos tratamentos de sincronização não comprometeu a eficiência do protocolo de sincronização para IATF em vacas holandesas de alta produção.