Method for improving timed insemination efficiency of dairy cow under summer condition

Abstract

The invention provides a method for improving the timed insemination efficiency of dairy cows under summer conditions, and the timed insemination efficiency of dairy cows under summer conditions is improved by applying at least three of the following means to cows. The method comprises the following steps: injecting GnRH, injecting PG, injecting eCG, injecting hCG, injecting ketoprofen, injecting A3, and embedding CIDR. Experiments show that the timed insemination efficiency of the dairy cow under the heat stress condition is remarkably improved by using CIDR, eCG, hCG, ketoprofen and the like, so that the reproductive capacity of the dairy cow under the summer condition is improved, and the method has important economic value and social value for guaranteeing the healthy development of the dairy cow breeding industry.

Description

Technical Field

[0001] The present invention belongs to the technical field of livestock breeding, and specifically relates to a method for improving the efficiency of timed artificial insemination of dairy cows under summer conditions. Background Art

[0002] Season has a significant impact on production performance indicators such as the growth, reproduction, and lactation of dairy cows (Collier et al., 2006). Cattle are one of the livestock species that are extremely sensitive to high temperatures (Chen et al., 2020), and high environmental temperature and humidity in summer are most likely to cause heat stress (HS) in dairy cows (Dos Santos et al., 2021). Heat stress is caused by the interaction of environmental factors such as air temperature, relative humidity, wind speed, and solar radiation (Dos Santos et al., 2021; Kamal et al., 2018), and is the main limiting factor for milk production in hot climates (Bouroutzika et al., 2020; Samma et al., 2020). Heat stress is the main stressor for high-yielding cows (Del Corvo et al., 2021). High-yielding cows have a high metabolic rate (Collier et al., 2006; Del Corvo et al., 2021) and are accompanied by related heat absorption (Del Corvo et al., 2021), making high-yielding dairy cows more vulnerable to the harmful effects of heat stress (de Barros et al., 2018; Collier et al., 2006), thereby inhibiting their production (Del Corvo et al., 2021).

[0003] When cattle are under heat stress, they are unable to dissipate excessive endogenous and exogenous heat sufficiently to maintain body heat balance (DelCorvo et al., 2021; Ouellet et al., 2021), which can trigger a series of physiological and behavioral responses (Ouellet et al., 2021) and reduce their production efficiency (Dos Santos et al., 2021). Heat stress can cause physiological imbalance in cattle (Dos Santos et al, 2021), leading to an increase in their core body temperature, a decrease in feed intake (Dos Santos etal., 2021), delayed development (Kamal et al., 2018), weight loss (Dos Santos et al., 2021), a decrease in milk production (Aguiar et al., 2020; Dos Santos et al., 2021; Ouellet et al., 2021; Chenet al., 2020), a reduction in fertility (de Barros et al., 2018; Garcia-Ispierto et al., 2013) and reproductive performance (Chang-Fung-Martel et al., 2021; Chen et al., 2020), as well as an increase in mortality (Chang-Fung-Martel et al., 2021; Zhang et al., 2020) and culling rate of dairy cows (Aguiar etal., 2020; Negrón-Pérez et al., 2019). Heat stress can cause a significant decrease in the efficiency of timed artificial insemination in cattle in summer, approaching 50%, and a significant delay in the recovery of fertility in cattle in autumn, about two months (Negrón-Pérez et al., 2019), indicating that heat stress can have a long-term impact on the reproductive capacity of dairy cows (Aguiar et al., 2020). Heat stress affects approximately 60% of the world's cattle herds and is a major factor contributing to the low conception rate in high-yielding dairy cow herds globally (Cebrian-Serrano et al., 2013). In addition, prenatal heat stress can have a lifelong negative impact on the growth and development of offspring (Ouellet et al., 2021), and postnatal heat stress can impair the recovery of the cattle production cycle (Garcia-Ispierto et al., 2013).

[0004] Therefore, it can be seen that heat stress can significantly reduce the efficiency of timed artificial insemination in dairy cows, and it is urgent to solve this problem. Summary of the Invention

[0005] The object of the present invention is to provide a method for improving the efficiency of timed artificial insemination of dairy cows under summer conditions. Specifically, the use of CIDR, eCG, hCG, ketoprofen, etc. can significantly improve the efficiency of timed artificial insemination of dairy cows under heat stress conditions, thereby improving the fertility of dairy cows under summer conditions.

[0006] To achieve the object of the present invention, the present invention provides a method for improving the efficiency of timed artificial insemination of dairy cows under summer conditions. By administering at least 3 of the following means to cows, the efficiency of timed artificial insemination of dairy cows under summer conditions is improved; The means include, but are not limited to, injecting GnRH (gonadotropin-releasing hormone), injecting PG (prostaglandin), injecting eCG (equine chorionic gonadotropin), injecting hCG (human chorionic gonadotropin), injecting ketoprofen, injecting A3 (luteinizing hormone-releasing hormone), implanting CIDR (controlled internal drug release device for cows).

[0007] Among them, CIDR can inhibit the development of the current dominant follicle and contribute to the formation of a new follicular wave. GnRH can promote luteal cells to produce more progesterone. Ketoprofen can prevent luteolysis by inhibiting cyclooxygenase (COX-1, COX-2) involved in the synthesis of PGF2α. Luteinizing hormone-releasing hormone A3 can promote the rupture and ovulation of mature follicles. Human chorionic gonadotropin hCG can stimulate the corpus luteum to produce progesterone. Equine chorionic gonadotropin eCG can promote follicular development.

[0008] Further, any one of the following schemes ①~⑥ is selected: ① GnRH+CIDR+PG+GnRH+hcG combination scheme On the nth day after calving of the cow, GnRH is injected for the first time, and CIDR is implanted at the same time; on the (n + 7)th day, PG is injected, and CIDR is removed at the same time; on the (n + 7 + 2)th day, GnRH is injected for the second time; on the (n + 7 + 2 + 1)th day, artificial insemination is performed; on the 5th day after artificial insemination, hCG is injected; Among them, the range of n is 34 - 37; The injection amount of GnRH each time is 100 μg / head; The injection amount of PG each time is 0.6 mg / head; The injection amount of hCG each time is 3000 IU / head; ② GnRH+CIDR+PG+eCG+GnRH combination scheme On the nth day after calving of the cow, GnRH is injected for the first time, and CIDR is implanted at the same time; on the (n + 7)th day, PG and eCG are injected, and CIDR is removed at the same time; on the (n + 7 + 2)th day, GnRH is injected for the second time; on the (n + 7 + 2 + 1)th day, artificial insemination is performed; Among them, the range of n is 34 - 37; The injection amount of GnRH each time is 100 μg / head; The dosage of PG per injection is 0.6 mg / head; The dosage of eCG per injection is 500 IU / head; ③ GnRH + CIDR + PG + eCG + GnRH + hcG combination scheme On the nth day after calving in cows, GnRH is injected for the first time, and CIDR is implanted simultaneously; on the (n + 7)th day, PG and eCG are injected, and CIDR is removed simultaneously; on the (n + 7 + 2)th day, GnRH is injected for the second time; on the (n + 7 + 2 + 1)th day, artificial insemination is carried out; hCG is injected on the 5th day after artificial insemination; Among them, the range of n is 34 - 37; The dosage of GnRH per injection is 100 ug / head; The dosage of PG per injection is 0.6 mg / head; The dosage of eCG per injection is 500 IU / head; The dosage of hCG per injection is 3000 IU / head; ④ GnRH + CIDR + PG + eCG + GnRH + hcG + ketoprofen combination scheme On the nth day after calving in cows, GnRH is injected for the first time, and CIDR is implanted simultaneously; on the (n + 7)th day, PG and eCG are injected, and CIDR is removed simultaneously; on the (n + 7 + 2)th day, GnRH is injected for the second time; on the (n + 7 + 2 + 1)th day, artificial insemination is carried out; hCG is injected on the 5th day after artificial insemination; ketoprofen is injected once in the evening of the 15th day and once in the morning of the 16th day after artificial insemination; Among them, the range of n is 34 - 37; The dosage of GnRH per injection is 100 ug / head; The dosage of PG per injection is 0.6 mg / head; The dosage of eCG per injection is 500 IU / head; The dosage of hCG per injection is 3000 IU / head; The dosage of ketoprofen per injection is 10 ml / head; ⑤ GnRH + PG + PG + GnRH + A3 + hCG combination scheme On the nth day after calving in cows, GnRH is injected for the first time; PG is injected once on the (n + 7)th day and once on the (n + 8)th day; on the (n + 8 + 1)th day, GnRH is injected for the second time; on the (n + 8 + 1 + 1)th day, artificial insemination is carried out, and A3 is injected simultaneously; hCG is injected on the 5th day after artificial insemination; Among them, the range of n is 34 - 37; The dosage of GnRH per injection is 100 ug / head; The dosage of PG per injection is 0.6 mg / head; The dosage of A3 per injection is 25 ug / head; The dosage of hCG per injection is 3000 IU / head; ⑥ GnRH + PG + PG + GnRH + A3 + hCG + ketoprofen combination On the nth day after calving, GnRH is injected for the first time; PG is injected once on the (n + 7)th day and the (n + 8)th day respectively; on the (n + 8 + 1)th day, GnRH is injected for the second time; on the (n + 8 + 1 + 1)th day, artificial insemination is carried out, and A3 is injected at the same time; hCG is injected on the 5th day after artificial insemination; ketoprofen is injected once in the evening of the 15th day and once in the morning of the 16th day after artificial insemination; Among them, the range of n is 34 - 37; The dosage of GnRH per injection is 100 μg / head; The dosage of PG per injection is 0.6 mg / head; The dosage of A3 per injection is 25 μg / head; The dosage of hCG per injection is 3000 IU / head; The dosage of ketoprofen per injection is 10 ml / head.

[0009] Preferably, the scheme ⑥ is adopted.

[0010] In the present invention, the range of n is 34 - 37.

[0011] Furthermore, the cattle are multiparous cows with 1 - 4 parity.

[0012] Furthermore, the cattle are dairy cows, preferably Holstein cows.

[0013] Furthermore, the semen dosage is 0.25 ml, and the number of effective spermatozoa input each time is not less than 12 million.

[0014] The time for cattle pregnancy examination is the 35th day after artificial insemination.

[0015] By means of the above technical solutions, the present invention has at least the following advantages and beneficial effects: The present invention provides a method for improving the efficiency of timed artificial insemination of dairy cows under summer conditions. Using CIDR, eCG, hCG, ketoprofen, etc. can significantly improve the efficiency of timed artificial insemination of dairy cows under heat stress conditions, and thus improve the fertility of dairy cows under summer conditions, which has important economic value and social value for ensuring the healthy development of the dairy farming industry. The present invention has multiple advantages such as low cost, simple operation, and zero milk discard, and has good promotion prospects. Detailed implementation manners

[0016] The following examples are used to illustrate the present invention, but are not used to limit the scope of the present invention. Unless otherwise specified, the technical means used in the examples are conventional means well known to those skilled in the art, and the raw materials used are all commercially available products.

[0017] GnRH and PG used in the following examples were purchased from Ningbo Sansheng Biotechnology Co., Ltd., ketoprofen was purchased from Foshan Nanhai Dongfang Aolong Pharmaceutical Co., Ltd. (containing 0.15 g ketoprofen per ml), and CIDR was purchased from Zoetis Biopharmaceutical Co., Ltd. eCG, hCG, and A3 were purchased from Ningbo Sansheng Biotechnology Co., Ltd.

[0018] In the following examples, the amount of GnRH injected each time was 100ug / head; The amount of PG injected each time was 0.6 mg / head; A3: 25ug / head per injection; The amount of eCG injected each time was 500 IU / head; The amount of hCG injected each time is 3000IU / head; The injection volume of ketoprofen is 10 ml / head per time; The amount of insemination is 0.25 ml of semen, and the amount of effective sperm infused each time is not less than 12 million.

[0019] Terms used in this invention: 0-7-9 single synchronization means that the cow is injected with GnRH on the 34th day after calving, PG is injected 7 days later, GnRH is injected 2 days later, and insemination is performed 1 day later.

[0020] Insemination refers to artificial insemination (artificial insemination).

[0021] Example 1 1. Experimental Methods Under summer heat stress conditions (June-September, THI>120), healthy Chinese Holstein cows with similar parity and body condition were selected for the experiment. On the 35th day after artificial insemination, B-ultrasound was used for pregnancy detection and the conception rate was calculated.

[0022] 1. Cattle selection and grouping, blood collection The experimental cattle selected were 1-4 parity cows, and each batch of cattle to be treated was randomly divided into 4 groups for operation until each group of experimental cattle reached more than 30. Blood was collected from cattle on the 1st, 5th, 8th, 11th, and 14th days after insemination, and serum was collected and stored in liquid nitrogen for metabolome sequencing. On the day of insemination, intestinal microorganisms were collected, and 2-3 grams of fresh feces (soft) at the end of the rectum were collected, placed in 2ml cryopreservation tubes, and stored in liquid nitrogen for intestinal microbial sequencing.

[0023] 2. Experimental treatment “0-7-9” optimization experiment processing: (1) GnRH+PG+GnRH group: local normal timed insemination program (0-7-9 single synchronization). GnRH was injected on the 34th day after delivery, PG was injected after an interval of 7 days, GnRH was injected after an interval of 2 days, and insemination was performed after an interval of 1 day.

[0024] (2)GnRH + CIDR + PG + GnRH + hcG group: GnRH was injected on the 34th day after parturition, and CIDR was implanted simultaneously; CIDR was removed after 7 days, and PG was injected; GnRH was injected 2 days later; insemination was carried out 1 day later; hCG was injected 5 days after insemination.

[0025] (3)GnRH + CIDR + PG + eCG + GnRH group: GnRH was injected on the 34th day after parturition, and CIDR was implanted simultaneously; CIDR was removed after 7 days, and PG and eCG were injected; GnRH was injected 2 days later; insemination was carried out 1 day later.

[0026] (4)GnRH + CIDR + PG + eCG + GnRH + hcG group: GnRH was injected on the 34th day after parturition, and CIDR was implanted simultaneously; CIDR was removed after 7 days, and PG and eCG were injected; GnRH was injected 2 days later; insemination was carried out 1 day later; hCG was injected 5 days after insemination.

[0027] (5)GnRH + CIDR + PG + eCG + GnRH + hcG + ketoprofen: GnRH was injected on the 34th day after parturition, and CIDR was implanted simultaneously; CIDR was removed after 7 days, and PG and eCG were injected; GnRH was injected 2 days later; insemination was carried out 1 day later; hCG was injected 5 days after insemination, and ketoprofen (10 ml / head / time) was injected on the evening of the 15th day and the morning of the 16th day after insemination.

[0028] "0 - 7 - 8 - 9" optimized experimental treatment: (1)GnRH + PG + PG + GnRH: GnRH was injected on the 34th day after parturition, PG was injected once each after 7 days and 8 days, GnRH was injected 1 day later, and insemination was carried out 1 day later; (2)GnRH + PG + PG + GnRH + A3 + hCG: GnRH was injected on the 34th day after parturition; PG was injected once each after 7 days and 8 days, GnRH was injected 1 day later; insemination was carried out 1 day later, and A3 was injected simultaneously during insemination; hCG was injected 5 days after insemination.

[0029] (3)GnRH + PG + PG + GnRH + A3 + hCG + ketoprofen: GnRH was injected on the 34th day after parturition; PG was injected once each after 7 days and 8 days, GnRH was injected 1 day later; insemination was carried out 1 day later, and A3 was injected simultaneously during insemination; hCG was injected 5 days after insemination, and ketoprofen (10 ml / head / time) was injected on the evening of the 15th day and the morning of the 16th day after insemination.

[0030] II. Experimental results 1. Comparison of different optimization methods of 0 - 7 - 9 single synchronization under summer heat stress conditions As shown in Table 1, the pregnancy rate of the GnRH+CIDR+PG+eCG+GnRH+hcG+ketoprofen group (52.67±4.87%) was the highest, significantly higher than that of all other groups. The pregnancy rates of the GnRH+CIDR+PG+GnRH+hcG group (41.53 ± 4.06%), GnRH+CIDR+PG+eCG+GnRH group (40.62±4.13%), and GnRH+CIDR+PG+eCG+GnRH+hcG group (45.60 ± 3.98%) were similar, all significantly higher than that of the GnRH+PG+GnRH group (9.17 ± 0.85%).

[0031] Table 1 Comparison of different optimization methods for 0-7-9 single synchronization under summer heat stress

[0032] Note: Superscript letters indicate significant differences.

[0033] 2. Comparison of different optimization methods for 0-7-9 single synchronization under summer heat stress As shown in Table 2, the timed insemination efficiency of the GnRH+PG+PG+ GnRH+A3+hCG group (58.43± 5.34%) was significantly higher than that of the GnRH+PG+PG+ GnRH group (31.46±4.06%).

[0034] Table 2 Comparison of different optimization methods for 0-7-8-9 single synchronization under summer conditions

[0035] 3. Comparison of the 0-7-9 and 0-7-8-9 optimization methods under summer heat stress As shown in Table 3, the timed insemination efficiency of the GnRH+PG+PG+GnRH+A3+hCG+ketoprofen group (65.22±7.43%) was significantly higher than that of the GnRH+PG+PG+GnRH+A3+hCG group (57.43±4.58%) and the GnRH+CIDR+PG+eCG+GnRH+hcG+ketoprofen group (52.68±5.04%).

[0036] Table 3 Comparison of timed insemination efficiency of different single synchronization optimization programs

[0037] In summary, under summer heat stress, the GnRH+PG+PG+GnRH+A3+hCG+ketoprofen program can significantly improve the timed insemination efficiency of dairy cows.

[0038] Although the present invention has been described in detail above with general descriptions and specific embodiments, modifications or improvements can be made thereto based on the present invention, which will be obvious to those skilled in the art. Therefore, these modifications or improvements made without departing from the spirit of the present invention fall within the scope of the present invention claimed.

[0039] References: 1. Aguiar LH, Hyde KA, Pedroza GH, et al. Heat stress impairs in vitro development of preantral follicles of cattle[J]. Anim Reprod Sci, 2020, 213: 106277. 2. Bouroutzika E, Kouretas D, Papadopoulos S, et al. Effects of Melatonin Administration to Pregnant Ewes under Heat-Stress Conditions, in Redox Status and Reproductive Outcome[J]. Antioxidants (Basel), 2020, 9(3): 266. 3. Collier RJ, Dahl GE, VanBaale MJ. Major advances associated with environmental effects on dairy cattle[J]. J Dairy Sci, 2006, 89(4): 1244-1253. 4. Chang-Fung-Martel J, Harrison MT, Brown JN, et al. Negative relationship between dry matter intake and the temperature-humidity index with increasing heat stress in cattle: a global meta-analysis[J]. Int J Biometeorol, 2021, 65(12): 2099-2109. 5. Chen KL, Wang HL, Jiang LZ, et al. Heat stress induces apoptosis through disruption of dynamic mitochondrial networks in dairy cow mammary epithelial cells[J]. In Vitro Cell Dev Biol Anim, 2020, 56(4): 322-331. 6. Cebrian-Serrano A, Salvador I, Raga E, et al. Beneficial effect of melatonin on blastocyst in vitro production from heat-stressed bovine oocytes[J]. Reprod Domest Anim, 2013, 48(5): 738-746. 7. Del Corvo M, Lazzari B, Capra E, et al. Methylome Patterns of Cattle Adaptation to Heat Stress[J]. Front Genet, 2021, 12: 633132. 8. Dos Santos MM, Souza-Junior JBF, Dantas MRT, et al. An updated review on cattle thermoregulation: physiological responses, biophysical mechanisms, and heat stress alleviation pathways[J]. Environ Sci Pollut Res Int, 2021, 28(24): 30471-30485. 9. de Barros FRO, Paula-Lopes FF. Cellular and epigenetic changes induced by heat stress in bovine preimplantation embryos[J]. Mol Reprod Dev, 2018, 85(11): 810-820. 10、Garcia-Ispierto I, Abdelfatah A, López-Gatius F. Melatonintreatment at dry-off improves reproductive performance postpartum in high-producing dairy cows under heat stress conditions[J]. Reprod Domest Anim,2013, 48(4): 577-583. 11、Kamal R, Dutt T, Patel M, et al. Heat stress and effect of shadematerials on hormonal and behavior response of dairy cattle: a review[J].TropAnim Health Prod, 2018, 50(4): 701-706. 12、Negrón-Pérez VM, Fausnacht DW, Rhoads ML. Invited review:Management strategies capable of improving the reproductive performance ofheat-stressed dairy cattle[J]. J Dairy Sci, 2019, 102(12): 10695-10710. 13、Sammad A, Wang YJ, Umer S, et al. Nutritional Physiology andBiochemistry of Dairy Cattle under the Influence of Heat Stress: Consequencesand Opportunities[J]. Animals (Basel), 2020, 10(5): 793. 14. Ouellet V, Boucher A, Dahl GE, et al. Consequences of maternal heat stress at different stages of embryonic and fetal development on dairy cows' progeny[J]. Anim Front, 2021, 11(6): 48-56.

Claims

1. A method for improving the efficiency of timed insemination of dairy cows under summer conditions, characterized in that: Improving the efficiency of timed insemination of dairy cows under summer conditions by administering at least three of the following means to the cows; The methods include: injection of GnRH, injection of PG, injection of eCG, injection of hCG, injection of ketoprofen, injection of A3, and implantation of CIDR.

2. The method according to claim 1, characterized in that: Choose any one of the following options ①~⑥: ①GnRH+CIDR+PG+GnRH+hcG combination regimen On the nth day after calving, the cow is injected with GnRH for the first time and CIDR is buried at the same time; on the n+7th day, PG is injected and CIDR is withdrawn at the same time; on the n+7+2th day, GnRH is injected for the second time; on the n+7+2+1th day, artificial insemination is performed; hCG is injected on the 5th day after artificial insemination; Among them, the range of n is 34-37; The amount of GnRH injected each time is 100ug / head; The amount of PG injected each time was 0.6 mg / head; The amount of hCG injected each time is 3000IU / head; ②GnRH+CIDR+PG+eCG+GnRH combination regimen On the nth day after calving, the cow is injected with GnRH for the first time and CIDR is buried at the same time; on the n+7th day, PG and eCG are injected and CIDR is withdrawn at the same time; on the n+7+2th day, GnRH is injected for the second time; on the n+7+2+1th day, artificial insemination is performed; Among them, the range of n is 34-37; The amount of GnRH injected each time is 100ug / head; The amount of PG injected each time was 0.6 mg / head; The amount of eCG injected each time was 500 IU / head; ③GnRH+CIDR+PG+eCG+GnRH+hcG combination On the nth day after calving, the cow is injected with GnRH for the first time and CIDR is buried at the same time; on the n+7th day, PG and eCG are injected and CIDR is withdrawn at the same time; on the n+7+2th day, GnRH is injected for the second time; on the n+7+2+1th day, artificial insemination is performed; hCG is injected on the 5th day after artificial insemination; Among them, the range of n is 34-37; The amount of GnRH injected each time is 100ug / head; The amount of PG injected each time was 0.6 mg / head; The amount of eCG injected each time was 500 IU / head; The amount of hCG injected each time is 3000IU / head; ④GnRH+CIDR+PG+eCG+GnRH+hcG+ketoprofen combination regimen The cow was injected with GnRH for the first time on the nth day after calving, and CIDR was buried at the same time; on the n+7th day, PG and eCG were injected, and CIDR was withdrawn at the same time; on the n+7+2th day, GnRH was injected for the second time; on the n+7+2+1th day, artificial insemination was performed; hCG was injected on the 5th day after artificial insemination; ketoprofen was injected once on the evening of the 15th day and the morning of the 16th day after artificial insemination; Among them, the range of n is 34-37; The amount of GnRH injected each time is 100ug / head; The amount of PG injected each time was 0.6 mg / head; The amount of eCG injected each time was 500 IU / head; The amount of hCG injected each time is 3000IU / head; The injection volume of ketoprofen is 10 ml / head per time; ⑤GnRH+PG+PG+GnRH+A3+hCG combination regimen The cow is injected with GnRH for the first time on day n after giving birth; PG is injected once on day n+7 and day n+8; GnRH is injected for the second time on day n+8+1; artificial insemination is performed on day n+8+1+1, and A3 is injected at the same time; hCG is injected on day 5 after artificial insemination; Among them, the range of n is 34-37; The amount of GnRH injected each time is 100ug / head; The amount of PG injected each time was 0.6 mg / head; A3: 25ug / head per injection; The amount of hCG injected each time is 3000IU / head; ⑥GnRH+PG+PG+GnRH+A3+hCG+ketoprofen combination regimen The cows were first injected with GnRH on the nth day after calving; PG was injected once on the n+7th day and the n+8th day; GnRH was injected for the second time on the n+8+1th day; artificial insemination was performed on the n+8+1+1th day, and A3 was injected at the same time; hCG was injected on the 5th day after artificial insemination; ketoprofen was injected once on the evening of the 15th day and the morning of the 16th day after artificial insemination; Among them, the range of n is 34-37; The amount of GnRH injected each time is 100ug / head; The amount of PG injected each time was 0.6 mg / head; A3: 25ug / head per injection; The amount of hCG injected each time is 3000IU / head; The injection volume of ketoprofen is 10ml / head each time.

3. The method according to claim 2, characterized in that Adopt plan ⑥.

4. The method according to any one of claims 1 to 3, characterized in that: The cattle are cows that have given birth 1 to 4 times.

5. The method according to any one of claims 1 to 3, characterized in that: The cattle are Holstein cows.

6. The method according to any one of claims 1 to 3, wherein the amount of sperm transfused is 0.25 ml of semen, and the amount of effective sperm transfused each time is not less than 12 million.

7. The method according to any one of claims 1 to 3, characterized in that: The time for checking cow pregnancy was 35 days after artificial insemination.

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