A method for improving the effect of synchronous estrus-timed insemination of buffaloes in summer

Abstract

The present invention provides a treatment method for improving the effect of synchronized estrus-timed insemination of buffaloes in summer. The treatment method is to inject melatonin into the multiparous buffaloes two days before the synchronized estrus treatment, i.e., on the 48th day after delivery, and then perform sympathetic estrus-timed insemination. The present invention also provides a new use of melatonin. The treatment method of the present invention effectively improves the synchronized estrus rate of multiparous milk buffaloes in summer, promotes follicle development and development speed, breeding rate and conception rate, and can increase the milk production and early embryo survival rate of buffaloes, reduce the somatic cell count, and does not require estrus detection, and synchronized insemination is convenient to operate.

Description

Technical Field

[0001] The invention belongs to the technical field of buffalo breeding in animal husbandry, and in particular relates to a processing method for improving the effect of synchronous estrus-timed insemination of buffalo in summer. Background Art

[0002] Buffaloes are seasonal breeding livestock, mainly distributed in tropical and subtropical areas, and their reproductive performance is easily affected by the environment and climate. Their reproductive performance is low in the non-breeding season, especially in summer. The main reason is that the heat stress in summer leads to silent estrus, irregular estrus ovulation, false estrus, and difficult estrus identification. It is difficult to grasp the ovulation time, or the estrus lasts for a long time, the postpartum anestrus period is long, the calving interval is long, and it is difficult to estimate the ovulation time. Therefore, it is difficult to grasp the timing of timely insemination, resulting in a low breeding conception rate, a late sexual maturity time, and a long estrus duration, which can reach 4-64h (Campanile et al., 2010, Perera, 2011); the estrus symptoms are not obvious, and estrus detection is relatively difficult, with a high follicle atresia rate and a low conception rate (30-40%) (Singh et al. 1984, Barkawi et al. 1993, DeRensis et al. 2005). Summer heat stress is an important factor affecting the low reproductive rate of lactating cows. It can inhibit the development of follicles (Guzeloglu et al., 2001), the function of granulosa cells (Yu et al., 2017), the synthesis of steroids (Roth et al., 2001), and the quality of oocytes (Al-Katanani et al., 2002; Ferreira et al., 2011). Studies have shown that small diameter ovulatory follicles or the discharge of immature follicles may reduce the conception rate and increase embryonic mortality in cattle (Vasconcelos et al., 2001;).

[0003] In addition, summer heat stress can cause buffaloes to go into estrus, ovulate, and have low conception rates, inhibit the development of follicles, reduce feed intake, milk production, and appetite, leading to an imbalance in the body's energy supply and demand. The imbalance in energy supply and demand after delivery will directly affect reproductive performance.

[0004] The milk production and breeding conception rate of buffaloes are lower in summer, mainly because the reproduction rate of lactating buffaloes is low due to heat stress in summer, which inhibits the development of follicles, causes no estrus, or quiet estrus. The rates of follicular cysts and ovarian cysts are high, the postpartum anestrus period is long, the calving interval is long, the postpartum uterine and ovarian function recovery is relatively slow, the estrus lasts for a long time, and it is difficult to estimate the ovulation time. Therefore, it is of great significance to improve the breeding rate and conception rate of buffaloes, and thus improve the reproduction rate and accelerate breed improvement. Summary of the invention

[0005] In order to solve the above technical problems, the present invention provides a processing method for improving the effect of synchronous estrus-timed insemination of buffaloes in summer.

[0006] To achieve the above object, the present invention adopts the following technical solutions:

[0007] A method for improving the effect of synchronized estrus-timed insemination of buffaloes in summer. The method comprises injecting melatonin into the parous buffaloes two days before synchronized estrus treatment, i.e., on the 48th day after giving birth, and then performing sympathetic estrus-timed insemination.

[0008] In the above treatment method, preferably, the parous buffalo is a buffalo 50 days after giving birth, and the melatonin is subcutaneously injected once for each buffalo at 18 mg / 50 kg body weight. (Calculated based on an average weight of 500 kg for a buffalo, 180 mg of melatonin is dissolved in a small amount of 75% ethanol solution and diluted to 5 ml with saline)

[0009] In the above-mentioned treatment method, preferably, the sympathetic estrus-timed insemination comprises the following steps:

[0010] S1. Inject gonadotropin-releasing hormone intramuscularly into healthy female buffaloes in estrus cycle. This day is recorded as day 0 of the synchronous estrus treatment of buffaloes.

[0011] S2, intramuscular injection of cloprostenol sodium on the 7th day after the synchronous estrus treatment of buffalo;

[0012] S3, on the 9th day after the synchronous estrus treatment of buffaloes, the second injection of gonadotropin-releasing hormone and mifepristone were injected at the same time to promote ovulation;

[0013] S4, artificial insemination was performed on the 10th day after the synchronized estrus treatment of buffaloes, i.e. 24 hours after the injection of mifepristone;

[0014] S5, intramuscular injection of human chorionic gonadotropin on the 15th day after the buffalo estrus synchronization treatment;

[0015] S6. On the 45th day after the synchronous estrus treatment of buffaloes, B-ultrasound was used to determine the pregnancy status of the cattle.

[0016] In the treatment method as described above, preferably, in step S1, gonadotropin-releasing hormone is administered at 400 μg / head.

[0017] In the treatment method as described above, preferably, in step S2, cloprostenol sodium is used at 0.5 mg / head.

[0018] In the treatment method as described above, preferably, in step S3, gonadotropin-releasing hormone is administered at 400 μg / head and mifepristone is administered at 0.4 mg / kg body weight.

[0019] In the treatment method as described above, preferably, in step S5, human chorionic gonadotropin is administered at 2000 IU / head.

[0020] Melatonin is used to improve buffalo's estrus, ovulation, breeding conception rate in summer, promote follicle development, increase the rate of follicle development, reduce the rate of follicle cysts and reduce the number of somatic cells in milk.

[0021] For the application as described above, preferably, the melatonin is administered subcutaneously to postpartum dairy buffaloes two days before the synchronous estrus treatment, that is, on the 48th day after delivery, at a time, 18 mg / 50 kg body weight of melatonin is injected subcutaneously to each buffalo, wherein the day of delivery is recorded as day 0, and the 50th day after delivery is recorded as day 0 of the synchronous estrus treatment for dairy cows, gonadotropin-releasing hormone is injected intramuscularly in the afternoon, cloprostenol sodium is injected intramuscularly in the afternoon of the 7th day, gonadotropin-releasing hormone is injected intramuscularly for the second time in the afternoon of the 9th day, and mifepristone is injected at the same time, artificial insemination is performed on the 10th day, that is, 24 hours after the injection of mifepristone, and human chorionic gonadotropin hCG is injected intramuscularly to the cattle receiving breeding on the 15th day (that is, the 5th day after artificial insemination), and the pregnancy status of the cattle is determined by B-ultrasound on the 45th day (that is, the 35th day after artificial insemination).

[0022] For the application as described above, preferably, the injection dose of gonadotropin-releasing hormone GnRH is 400 μg / head; mifepristone is administered at 0.4 mg / kg body weight; and artificial insemination is performed 24 hours after the injection of mifepristone.

[0023] In the application as described above, preferably, human chorionic gonadotropin is administered at 2000 IU / head.

[0024] The beneficial effects of the present invention are:

[0025] The invention provides a treatment method for improving the effect of synchronized estrus-timed insemination of buffaloes in summer. Specifically, the method comprises the following steps: after injecting melatonin two days before synchronized estrus treatment (48 days after delivery), a treatment method for sympathetic estrus-timed insemination is performed. After subcutaneous injection of melatonin two days before synchronized estrus treatment, follicle development is promoted and the follicle development rate, the diameter and number of large follicles and ovulation follicles are increased, so that the dairy buffaloes have a higher estrus and ovulation ratio in the non-breeding season, the follicle cyst rate is reduced, the follicle development and ovulation are promoted, and the estrus conception rate is improved. The method can effectively increase the daily milk production of the buffaloes, reduce the number of somatic cells in the milk, and simultaneously increase the protein rate, lactose content and milk fat rate in the milk components.

[0026] The present invention also provides a new use of melatonin, specifically the use of melatonin in improving the estrus, ovulation, breeding conception rate of buffaloes in summer, promoting follicle development, increasing the follicle development rate, reducing the follicle cyst rate and reducing the somatic cell count in milk. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a diagram illustrating the experimental operation process of the present invention.

[0028] Figure 2 Effects of different melatonin treatments on the maximum follicle diameter

[0029] Figure 3 The hybrid buffaloes were injected with different melatonin treatments and treated with GPGMH for estrus synchronization. The follicle development pattern from the 0th day of estrus synchronization to the maximum follicle diameter was shown in the logarithm of the x-coordinate and y-coordinate values.

[0030] Figure 4 The effect of different treatments of melatonin on the blood melatonin of lactating buffaloes.

[0031] Figure 5 The effect of melatonin with different treatments on immunoglobulin M (IgM) in the blood of lactating buffaloes. DETAILED DESCRIPTION

[0032] The following examples are used to further illustrate the present invention, but should not be construed as limiting the present invention. Without departing from the spirit and substance of the present invention, modifications or substitutions made to the present invention all belong to the scope of the present invention.

[0033] Unless otherwise specified, the technical means used in the examples are conventional means well known to those skilled in the art. Unless otherwise specified, all reagents used in the present method are of analytical grade or above.

[0034] Example 1

[0035] In order to improve the existing estrus synchronization scheme, the problem of poor summer estrus synchronization effect, reduce the somatic cell count of buffaloes, and improve the conception rate of breeding. Melatonin + estrus synchronization timed insemination scheme is carried out. The process is shown in Figure 1As shown, 62 healthy peripartum hybrid buffaloes in good physical condition were selected. In July, female buffaloes on the 50th day after delivery (the day of delivery was day 0) were selected and divided into 3 groups according to age, weight, milk production, parity and other indicators. Group T1 was subcutaneously injected with 6 mg / 50 kg body weight of melatonin every day from four days before synchronous estrus (the 46th day after delivery) for 3 consecutive days, once a day, for a total of 3 injections (i.e., treatment group T1 was subcutaneously injected with melatonin every day for the three days before synchronous estrus); Group T2 was subcutaneously injected with 18 mg / 50 kg body weight of melatonin from two days before synchronous estrus (i.e., the 48th day after delivery) (i.e., treatment group T2 was subcutaneously injected with a single time (single time means only one injection) of melatonin two days before synchronous estrus), and the control group Control was subcutaneously injected with 5 ml of normal saline from four days before synchronous estrus (the 46th day after delivery) for 3 consecutive days, once a day, for a total of 3 injections (i.e., the control group was injected with normal saline). Among them, 18mg / 50kg body weight is calculated based on the average weight of a cow of 500kg, which is 180mg of melatonin. First dissolve it in 1ml of 75% ethanol solution, dilute it to 5ml with saline, and then inject it.

[0036] All cattle received synchronized estrus and artificial insemination treatments, and the specific operations were as follows: the 50th day after delivery was counted as the 0th day of synchronized estrus treatment for buffaloes, and gonadotropin-releasing hormone (GnRH) was injected intramuscularly at 400 μg / head in the afternoon. Ultrasound examination was performed from the 6th day (i.e., the day before PGF2ɑ injection) to the 12th day of ovulation (i.e., 72 hours after the second injection of GnRH), and the follicle development and estrus and ovulation conditions were recorded; cloprostenol sodium (PGF2ɑ) was injected intramuscularly at 0.5 mg / head in the afternoon of the 7th day, and 100 μg / head was injected intramuscularly on the 9th day. On the afternoon of the 15th day (48 hours after the injection of PGF2ɑ), the second intramuscular injection of GnRH (200μg / head) was given, and mifepristone (0.4mg / kg body weight) was injected at the same time to promote ovulation. Artificial insemination was performed on the afternoon of the 10th day (24 hours after the second injection of GnRH). On the 15th day (i.e., the 5th day after artificial insemination), the cows that received mating were injected intramuscularly with hCG (2000IU / head) to promote early embryo survival. On the 45th day (i.e., the 35th day after artificial insemination), B-ultrasound was used to determine the pregnancy status of the cows.

[0037] B-ultrasound was used to observe the growth and development of follicles and ovulation on the 6th to 12th day of the treatment of synchronous estrus and artificial insemination. The effects of different treatment groups on the development of buffalo follicles and the duration of estrus were measured, and the average values ​​were taken. The results are shown in Table 1, and the maximum follicle diameter is plotted as shown in Figure 1. Figure 1 shown.

[0038] Table 1 Effects of melatonin in different treatments on follicle development and estrus duration of hybrid buffalo

[0039]

[0040] The results showed that the injection of melatonin before estrus in hybrid buffaloes at the same time, different treatment methods and different time periods had significant effects on the diameter of large follicles. The maximum follicle diameter of the T2 group (13.8±1.4mm) was significantly larger than that of the other groups (such as Figure 1 ), among which, the diameter of the large follicles in the control group was significantly different only from that in the single injection group T2 (p<0.05), and there was no significant difference between the diameter of the large follicles in the single injection group T1 and that in the single injection group T2 (p>0.05). The initial follicle diameter of the T2 group was 9.3±0.9mm, which was larger than that of the other groups, but the difference was not significant (p>0.05). The interval from the second GnRH to ovulation in the T2 group was 8.7±1.7h, the interval from the second GnRH to estrus was 23.6±1.1h, and the duration of estrus was 15.7±0.7h, which was shorter than that of the other groups, but there was no significant difference (p>0.05) (Table 1). Although the experimental results of different dose groups were not significantly different, compared with the blank control group (0), the melatonin T2 group can promote the development of follicles and prolong the estrus time of hybrid buffaloes to a certain extent, which has certain practical production significance.

[0041] Table 2 Effects of different doses of melatonin injected into hybrid buffalo on estrus, ovulation and conception rate

[0042]

[0043] The results in Table 2 show that when hybrid buffaloes were injected with melatonin of different treatments before estrus, melatonin had a significant effect on the estrus rate, ovulation rate, conception rate, and follicular cyst rate of multiparous buffaloes. The estrus, ovulation and conception rates of the experimental group were significantly (p<0.05) higher than those of the control group. The estrus rate of hybrid buffaloes in the single injection group T2 was 91.3% (21 / 23), the ovulation rate was 87.0% (20 / 23), the conception rate was 78.3% (18 / 23), and the follicle growth rate reached 1.8±0.32mm / day, which was significantly (p<0.05) higher than that of the control group, but there was no significant difference between them and the multiple injection group T1 (p>0.05); compared with other experimental groups, the follicular cyst rate (0%) of the T2 group was significantly (p<0.05) lower than that of other treatment groups. According to ( Figure 2 ) shows that the follicle development of T2 in the single injection group is more regular and stable, and the development speed and the maximum diameter of the ovulatory follicle are higher than those in other groups, but there is no significant difference (p>0.05) ( Figure 2 ). This indicates that injected melatonin can significantly increase the estrus rate, ovulation rate, conception rate, and follicle growth rate of buffaloes, and reduce the rate of follicular cysts.

[0044] 3. The results of the effect of different doses of melatonin injection on milk production of hybrid buffaloes using the above-mentioned estrus synchronization-timed insemination scheme are shown in Table 3. Among them, the sampling time is calculated based on the day of estrus synchronization treatment as day 0.

[0045] Table 3 Daily milk production of hybrid buffaloes in each group after injection of different treatments of melatonin

[0046]

[0047]

[0048] Note: For the same indicator, different lowercase letters in the same row indicate significant differences (P<0.05).

[0049] The results in Table 3 above show that the effect of subcutaneous injection of melatonin on the production performance of hybrid buffaloes showed that the milk production showed a gradual increase in the first 5 days. Among them, subcutaneous injection of melatonin (T2 group) from 46 days after delivery had a more significant effect on increasing milk production in dairy buffaloes. The milk production in the experimental group after subcutaneous injection of melatonin was higher than that in the control group, but the difference was not significant (P>0.05). The milk production in the T2 single injection group after subcutaneous injection of melatonin tended to be higher than that in other groups, and there was no significant difference between the other groups (P>0.05).

[0050] The milk production of the multiple injection group and the single injection group on the day before melatonin injection was 3.04±1.9 and 3.23±1.6, respectively, with no significant difference (p>0.05). After stopping the melatonin injection, the milk production of the buffaloes in the multiple injection group and the single injection group was 3.17±2.3 and 3.49±1.8, respectively, which was higher than the trend before injection, but the difference was not significant (p>0.05). Until the 10th day after treatment, the milk production in the multiple injection group and the single injection group was 4.11±2.9 and 4.48±2.9, respectively, which was also significantly higher than the milk production before injection (p<0.05). On the 8th, 9th and 10th days, the T2 single injection group was higher than the multiple injection group and the control group, and the trend gradually stabilized. The milk production of the treatment group was higher than that of the control group, indicating that the injection of melatonin increased the milk production to a certain extent (see Table 3).

[0051] Melatonin and IgM in the blood of lactating buffaloes were examined after subcutaneous injection of different doses of melatonin. Melatonin in the blood was determined according to the specific operation in the instructions of the bovine melatonin (MT) assay kit of Shanghai ELISA Biotechnology Co., Ltd. IgM in the blood was determined according to the specific operation in the instructions of the bovine immunoglobulin M (IgM) assay kit of Shanghai ELISA Biotechnology Co., Ltd. The test results are shown in Figure 3 and Table 4.

[0052] Table 4 Serum biochemical parameters of each group of hybrid buffaloes after injection of different doses of melatonin

[0053]

[0054] Note: For the same index, different lowercase letters in the same column indicate significant differences (P<0.05). Subcutaneous injection of exogenous melatonin has a significant effect on the blood biochemical indexes of dairy buffaloes, and the concentration of melatonin in the blood has increased. Figure 4 As shown, for both the single injection group (T2 group) (18 mg / 50 kg body weight / one time) and the multiple injection group (T1 group) (6 mg / 50 kg body weight / day, three days in total), the melatonin concentration in the blood after the first blood collection (the first day after melatonin injection) was significantly increased compared with the 0th blood collection (before melatonin injection) (p<0.05). However, the melatonin concentration in the blood after the second and third blood collections (the 5th and 10th days after melatonin injection) was not significantly different from the 0th blood collection (p>0.05), and the melatonin concentration in the blood between the single injection group (18 mg / 50 kg body weight) and the multiple injection group (6 mg / 50 kg body weight) was not significantly different (p>0.05).

[0055] This indicates that subcutaneous injection of different doses of melatonin has little effect on the melatonin level in the blood of lactating buffaloes.

[0056] Subcutaneous injection of exogenous melatonin had a significant effect on the IgM concentration in the blood of lactating buffaloes. Figure 5 As shown, the IgM concentration in the blood after the 0th blood collection (before melatonin injection) was significantly lower than that in the 1st blood collection (the first day after melatonin injection) (p<0.05). As the number of treatment days increased, the IgM content in the blood showed a gradual downward trend, but there was no significant difference between the blood collection times (p>0.05). At the same time, the IgM concentration in the blood of the single injection group (18 mg / 50 kg body weight) and the multiple injection group (6 mg / 50 kg body weight) showed the same trend of change, but there was no statistical difference (p>0.05).

[0057] 5. After melatonin injection, the synchronized estrus-timed insemination scheme was adopted to measure the milk components of each group, including total solids, fat-to-protein ratio, urea nitrogen, lactose content, somatic cell count, and milk fat rate. The results are shown in Table 5.

[0058] Table 5 Effects of different melatonin treatments on milk components in early lactation Note: Different lowercase letters a, b in the same column indicate significant differences (P<0.05).

[0059]

[0060] It can be seen from Table 5 above that before melatonin injection, there were no significant differences in milk fat rate, lactose content, non-fat milk solids analysis, total solids, urea nitrogen, somatic cell count and other groups (P>0.05). Only the protein rate of the T2 group after a single melatonin injection was significantly higher (P<0.05) than that of the control group, and there was no significant difference between the T2 group and the T1 group after multiple melatonin injections (P>0.05).

[0061] After stopping the injection of melatonin, the somatic cell count in buffalo milk above the somatic cell count (SCC = 500,000 / ml) showed a downward trend, and the downward trend in the treatment group was obvious compared with that before the melatonin treatment. On the 10th day after stopping the injection of melatonin, it can be seen that the milk fat rate, protein rate, lactose content, non-fat milk solids analysis, and total solids in the treatment group were higher than those in the control group, but there were no significant differences between the groups (P>0.05). There were significant differences in urea nitrogen and somatic cell count (P<0.05), among which the urea nitrogen and somatic cell count of the T2 group after a single injection of melatonin were significantly lower (P<0.05) than those of the control group, and there was no significant difference between the T1 group with multiple injections of melatonin (P>0.05). There was no significant difference in the number of somatic cells between the treatment group and the control group before melatonin injection (P>0.05). On the 10th day after stopping the injection of melatonin, it can be seen that the number of somatic cells in the treatment group was significantly lower than that in the control group (P<0.05); it was also significantly lower than the number of cells before melatonin injection (P<0.05), which was at a subhealthy level. However, there was no significant difference in the number of somatic cells at each time point after treatment in the two groups with different doses of melatonin injection (p>0.05). This experimental study shows that subcutaneous injection of melatonin can reduce the number of somatic cells in the milk of lactating buffaloes (the number of somatic cells in milk is a very important indirect indicator of the health of the cow's udder. The increase in somatic cell count (SCC) will cause a decrease in milk production and a decrease in the quality of buffalo milk, which greatly affects the nutritional value of buffalo milk).

[0062] Example 2

[0063] A method for treating the effect of synchronized estrus in summer and timed insemination by injecting melatonin before synchronized estrus for buffaloes. Healthy buffaloes without reproductive tract diseases are selected. Rectal examination is performed before the test. Cattle with reproductive tract diseases (asymmetric uterine horns on both sides, follicular cysts, ovarian cysts, large uterine horns, and inflammation) cannot be used for the test. The process can be as follows: Figure 5 The specific scheme is as follows:

[0064] Two days before the synchronous estrus treatment: the day of delivery was recorded as day 0. On the 48th day after delivery (the first week), a one-time subcutaneous injection of melatonin 18 mg / 50 kg body weight was given to each head at 15:00 pm on Monday afternoon to promote follicle development.

[0065] Day 0 of estrus synchronization treatment: On the 50th day after parturition (the first week), one or more healthy buffaloes in estrus cycle were intramuscularly injected with the first GnRH at 15:00 pm on Wednesday afternoon, with an injection dose of 400 μg / head to induce estrus.

[0066] Day 6 of estrus synchronization treatment: 56 days after delivery, B-ultrasound examination from the 6th day of estrus synchronization (one day before PGF2ɑ injection) to ovulation on the 12th day (i.e. 72h after GnRH injection), recording the follicle development and estrus, ovulation status.

[0067] Day 7 of estrus synchronization treatment: On the 57th day after delivery (the second week), PGF2ɑ was injected intramuscularly at 15:00 pm on Wednesday afternoon, with an injection dose of 0.5 mg / head to initiate estrus.

[0068] Day 9 of estrus synchronization treatment: On the 59th day after parturition (the second week), the second intramuscular injection of GnRH (400 μg / head) was given at 15:00 pm on Friday afternoon, and mifepristone (0.4 mg / kg) was injected intramuscularly at the same time to promote ovulation.

[0069] Day 10 of estrus synchronization: Artificial insemination was performed at 15:00 pm on Saturday afternoon, 60 days after delivery (second week). It should be noted that before each artificial insemination, the insemination gun was disinfected with alcohol, the vulva was disinfected with potassium permanganate disinfectant (0.1 mol / L), and the artificial insemination personnel ensured that the fingernails were cut short; the insemination technique was mastered and a disposable insemination gun holster was used. The semen was thawed quickly, the thawing temperature was 37.5 degrees Celsius, and the sperm motility was checked under a microscope. The sperm motility after thawing was higher than 0.3.

[0070] On the 11th day of estrus synchronization treatment: B-ultrasound is used to detect ovulation in the morning. If no ovulation is found in the cow, a second artificial insemination will be performed at 15:00 in the afternoon.

[0071] Day 15 of estrus synchronization: On Thursday afternoon at 16:00 pm (i.e., 5 days after artificial insemination), 65 days after delivery (third week), hCG (2000 IU / head) is injected intramuscularly to the cows to promote early embryo survival rate. Note: It is strictly forbidden to use expired hormones; disposable syringes are used for injection.

[0072] Day 45 of estrus synchronization: On the 110th day after delivery (week 6, Monday) (i.e. 35 days after artificial insemination), use B-ultrasound to diagnose pregnancy at 10:00 am. Pay attention to the estrus and ovulation of the cows and keep records.

[0073] The above-mentioned synchronized estrus and timed insemination program is operated to take into account the problem of early embryonic death. The first pregnancy diagnosis is made by observing whether the cattle have returned to estrus. To further improve the accuracy of diagnosis, pregnancy diagnosis is made on the 45th day after artificial insemination, and B-ultrasound is used to determine the pregnancy status of the cattle and record it.

[0074] The above-mentioned method of the present invention can improve the estrus rate of the reproductive performance cows by injecting melatonin and combining GPGMH estrus synchronization treatment in the postpartum hybrid buffaloes in summer, and the ovulation rate and conception rate are 91.3%, 87.0% and 78.3% respectively. In summer, the estrus rate, ovulation rate and conception rate of the cows are 86.7%, 76.7% and 33.3% respectively when the traditional GPG estrus synchronization scheme is used to treat buffaloes. In terms of production performance, milk production slowly increases after melatonin injection, and the injection dose of 18 mg / 50 kg body weight group increases (P>0.05), which is 16.61% higher than the control group.

[0075] The method of the present invention is to inject 18 mg / 50 kg body weight of melatonin into each hybrid buffalo subcutaneously at 48 days after delivery and two days before the synchronous estrus treatment, which can promote follicular development and follicular development speed, increase the maximum ovulation follicle diameter (P<0.05), improve the ovulation rate and breeding conception rate, and improve the synchronous estrus effect. On the 10th day after stopping the injection of melatonin, the indicators such as milk protein rate, milk fat rate, lactose rate, etc. can be significantly improved, the urea nitrogen level and somatic cell count in milk are reduced, the blood sugar level is increased, the milk production performance of buffalo is improved, and the milk production and early embryo survival rate are improved. It can be seen that the method of the present invention can significantly improve the promotion of follicular development and follicular development speed, estrus, ovulation and breeding conception rate of buffalo in summer, reduce the follicular cyst rate, reduce the early embryo mortality rate, reduce the somatic cell count, reduce the incidence of uterine inflammation and endometritis, reduce costs, save breeding costs, and improve breeding benefits. Moreover, the present invention is relatively easy to operate, does not require estrus identification, is a programmed synchronous estrus timed insemination scheme, and is easy to promote and apply.

Claims

1. A non-therapeutic method for improving the effect of synchronous estrus-timed insemination of buffaloes in summer, characterized in that: The treatment method is to inject melatonin into the parous buffalo two days before the synchronous estrus treatment, i.e., on the 48th day after calving, and then perform sympathetic estrus-timed insemination; The multiparous buffalo is a buffalo 50 days postpartum, and the melatonin is subcutaneously injected once for each buffalo at 18 mg / 50 kg body weight; The sympathetic estrus-timed insemination comprises the following steps: S1. Inject gonadotropin-releasing hormone intramuscularly into healthy female buffaloes in estrus cycle; this day is recorded as day 0 of the buffalo estrus synchronization treatment; S2, intramuscular injection of cloprostenol sodium on the 7th day after the synchronous estrus treatment of buffalo; S3, on the 9th day after the synchronous estrus treatment of buffaloes, the second injection of gonadotropin-releasing hormone and mifepristone were injected at the same time to promote ovulation; S4, artificial insemination was performed on the 10th day after the synchronized estrus treatment of buffaloes, i.e. 24 hours after the injection of mifepristone; S5. On the 15th day after the synchronized estrus treatment of buffaloes, human chorionic gonadotropin was injected intramuscularly to promote early embryo survival; S6. On the 45th day after the synchronous estrus treatment of buffaloes, the pregnancy status of the cattle was determined by B-ultrasound; In step S1, gonadotropin-releasing hormone was administered at 400 μg / head.

2. The processing method according to claim 1, characterized in that In step S2, cloprostenol sodium is used at 0.5 mg / head; In step S3, gonadotropin-releasing hormone was administered at 400 μg / head, and mifepristone was administered at 0.4 mg / kg body weight.

3. The processing method according to claim 1, characterized in that: In step S5, human chorionic gonadotropin is administered at 2000 IU / head.

4. The non-therapeutic use of melatonin for improving summer estrus, ovulation, breeding conception rate of buffalo, promoting follicular development, increasing follicular development rate, reducing follicular cyst rate and reducing somatic cell count in milk, characterized in that: The melatonin is subcutaneously injected once at 18 mg / 50 kg body weight for each cow two days before the synchronized estrus treatment, that is, on the 48th day after delivery; the day of delivery is recorded as day 0, and the 50th day after delivery is recorded as day 0 of the synchronized estrus treatment for dairy cows. Gonadotropin-releasing hormone is injected intramuscularly in the afternoon, cloprostenol sodium is injected intramuscularly in the afternoon of the 7th day, gonadotropin is injected intramuscularly for the second time in the afternoon of the 9th day, artificial insemination is performed in the afternoon of the 10th day, and human chorionic gonadotropin is injected intramuscularly to the cows that receive breeding on the 15th day. The pregnancy status of the buffalo is determined by B-ultrasound on the 45th day after the synchronized estrus treatment for buffaloes.

5. The use according to claim 4, characterized in that The injection dose of gonadotropin-releasing hormone is 400 μg / head; mifepristone is administered at 0.4 mg / kg body weight; artificial insemination is performed 24 hours after the injection of mifepristone.

6. The use according to claim 4, characterized in that Human chorionic gonadotropin was administered at 2000 IU / head.

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