A method for improving the efficiency of timed artificial insemination of dairy cows under summer conditions

Abstract

The application provides a method for improving the efficiency of timed insemination of dairy cows under summer conditions, which improves the efficiency of timed insemination of dairy cows under summer conditions by applying at least three of the following means to the cows; the means include: injection of GnRH, injection of PG, injection of eCG, injection of hCG, injection of ketoprofen, injection of A3, and embedding CIDR. Experiments show that the use of CIDR, eCG, hCG, ketoprofen and the like significantly improves the efficiency of timed insemination of dairy cows under heat stress conditions, thereby improving the fecundity of dairy cows under summer conditions, and has important economic value and social value for guaranteeing the healthy development of the dairy farming industry.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of livestock breeding, and in particular relates to a method for improving the efficiency of timed artificial insemination of dairy cows under summer conditions. BACKGROUND

[0002] Season has a significant impact on the growth, reproduction and lactation performance indicators of dairy cows (Collier et al., 2006). Cattle is one of the livestock that is extremely sensitive to high temperature (Chen et al., 2020), and the high environmental temperature and humidity in summer is 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 of milk yield in hot climate (Bouroutzika et al., 2020; Samma et al., 2020). Heat stress is the main stress source of high-yield cows (Del Corvo et al., 2021), and high-yield cows have high metabolic rate (Collier et al., 2006; Del Corvo et al., 2021) and associated endothermy (Del Corvo et al., 2021), making high-yield cows more susceptible 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] Cattle cannot sufficiently dissipate excessive endogenous and exogenous heat to maintain body heat balance when they are under heat stress (Del Corvo et al., 2021; Ouellet et al., 2021), which will trigger a series of physiological and behavioral responses (Ouellet et al., 2021) and reduce their production efficiency (Dos Santos et al., 2021). Heat stress will trigger physiological imbalance in cattle (Dos Santos et al., 2021), leading to an increase in core body temperature, a decrease in feed intake (Dos Santos et al., 2021), a delay in development (Kamal et al., 2018), a decrease in body weight (Dos Santos et al., 2021), a decrease in milk production (Aguiar et al., 2020; Dos Santos et al., 2021; Ouellet et al., 2021; Chen et al., 2020), a decrease in fertility rate (de Barros et al., 2018; Garcia-Ispierto et al., 2013) and reproductive performance (Chang-Fung-Martel et al., 2021; Chen et al., 2020), and an increase in mortality (Chang-Fung-Martel et al., 2021; Zhang et al., 2020), the culling rate of dairy cows (Aguiar et al., 2020; Negrón-Pérez et al., 2019). Heat stress will cause the timed insemination efficiency of summer cows to decrease significantly by nearly 50%, and the recovery of fertility of autumn cows will be significantly delayed by about two months (Negrón-Pérez et al., 2019), which indicates that heat stress will have a long-term impact on the fertility of dairy cows (Aguiar et al., 2020). Heat stress affects about 60% of cattle herds worldwide and is the main factor for low conception rates in high-yield dairy herds (Cebrian-Serrano et al., 2013). In addition, prenatal heat stress will have a lifelong negative impact on the growth and development of offspring (Ouellet et al., 2021), and postnatal heat stress will impair the recovery of the cow production cycle (Garcia-Ispierto et al., 2013).

[0004] Therefore, heat stress can significantly reduce the timed insemination efficiency of dairy cows, which needs to be solved urgently. SUMMARY

[0005] The purpose of the present application is to provide a method for improving the efficiency of timed insemination of dairy cows under summer conditions, specifically using CIDR, eCG, hCG, ketoprofen, etc. to significantly improve the efficiency of timed insemination of dairy cows under heat stress conditions, thereby improving the reproductive performance of dairy cows under summer conditions.

[0006] To achieve the purpose of the present application, the present application provides a method for improving the efficiency of timed insemination of dairy cows under summer conditions, which improves the efficiency of timed insemination of dairy cows under summer conditions by administering at least three of the following means to the cows;

[0007] The means include but are not limited to injection of GnRH (gonadotropin-releasing hormone), injection of PG (prostaglandin), injection of eCG (equine chorionic gonadotropin), injection of hCG (human chorionic gonadotropin), injection of ketoprofen, injection of A3 (luteinizing hormone-releasing hormone), and embedding of CIDR (progesterone vaginal suppository for cattle).

[0008] Among them, CIDR can inhibit the development of the current dominant follicle, which helps the formation of new follicle wave. GnRH can promote luteal cells to produce more progesterone, and ketoprofen can prevent luteolysis by inhibiting cyclooxygenase (COX-1, COX-2) involved in PGF 2α synthesis. Luteinizing hormone-releasing hormone A3 can promote mature follicle rupture and ovulation, and human chorionic gonadotropin hCG can stimulate luteal progesterone production. Equine chorionic gonadotropin eCG promotes follicle development.

[0009] Further, any one of the following schemes ①~⑥ is selected:

[0010] ① GnRH+CIDR+PG+GnRH+hcG combination scheme

[0011] The first injection of GnRH is performed on the n th day after delivery of the cow, and CIDR is embedded 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, the second injection of GnRH is performed; on the n+7+2+1 th day, artificial insemination is performed; and hCG is injected on the 5 th day after artificial insemination;

[0012] Among them, n is in the range of 34-37;

[0013] The injection amount of GnRH is 100ug per head;

[0014] The injection amount of PG is 0.6mg per head;

[0015] The injection amount of hCG is 3000IU per head;

[0016] ② GnRH+CIDR+PG+eCG+GnRH combination scheme

[0017] The first injection of GnRH is performed on the n day after delivery, and CIDR is implanted at the same time; PG and eCG are injected on the n+7 day, and CIDR is removed at the same time; the second injection of GnRH is performed on the n+7+2 day; artificial insemination is performed on the n+7+2+1 day;

[0018] wherein n ranges from 34 to 37;

[0019] The injection amount of GnRH is 100 ug per head each time;

[0020] The injection amount of PG is 0.6 mg per head each time;

[0021] The injection amount of eCG is 500 IU per head each time;

[0022] ③ GnRH+CIDR+PG+eCG+GnRH+hcG combination scheme

[0023] The first injection of GnRH is performed on the n day after delivery, and CIDR is implanted at the same time; PG and eCG are injected on the n+7 day, and CIDR is removed at the same time; the second injection of GnRH is performed on the n+7+2 day; artificial insemination is performed on the n+7+2+1 day; hCG is injected on the 5th day after artificial insemination;

[0024] wherein n ranges from 34 to 37;

[0025] The injection amount of GnRH is 100 ug per head each time;

[0026] The injection amount of PG is 0.6 mg per head each time;

[0027] The injection amount of eCG is 500 IU per head each time;

[0028] The injection amount of hCG is 3000 IU per head each time;

[0029] ④ GnRH+CIDR+PG+eCG+GnRH+hcG+ketoprofen combination scheme

[0030] The first injection of GnRH is performed on the n day after delivery, and CIDR is implanted at the same time; PG and eCG are injected on the n+7 day, and CIDR is removed at the same time; the second injection of GnRH is performed on the n+7+2 day; artificial insemination is performed on the n+7+2+1 day; hCG is injected on the 5th day after artificial insemination; ketoprofen is injected on the evening of the 15th day after artificial insemination and on the morning of the 16th day;

[0031] wherein n ranges from 34 to 37;

[0032] The injection amount of GnRH is 100 ug per head each time;

[0033] The injection amount of PG is 0.6 mg per head each time;

[0034] eCG 500 IU / animal per injection;

[0035] hCG 3000 IU / animal per injection;

[0036] Ketoprofen 10 ml / animal per injection;

[0037] (5) GnRH + PG + PG + GnRH + A3 + hCG combination regimen

[0038] GnRH is injected for the first time on the n day after delivery; PG is injected once on the n+7 day and the n+8 day; GnRH is injected for the second time on the n+8+1 day; A3 is injected on the n+8+1+1 day, when artificial insemination is performed; hCG is injected on the 5th day after artificial insemination;

[0039] wherein n ranges from 34 to 37;

[0040] GnRH 100 ug / animal per injection;

[0041] PG 0.6 mg / animal per injection;

[0042] A3 25 ug / animal per injection;

[0043] hCG 3000 IU / animal per injection;

[0044] (6) GnRH + PG + PG + GnRH + A3 + hCG + Ketoprofen combination regimen

[0045] GnRH is injected for the first time on the n day after delivery; PG is injected once on the n+7 day and the n+8 day; GnRH is injected for the second time on the n+8+1 day; A3 is injected on the n+8+1+1 day, when artificial insemination is performed; hCG is injected on the 5th day after artificial insemination; Ketoprofen is injected once on the evening of the 15th day after artificial insemination and on the morning of the 16th day;

[0046] wherein n ranges from 34 to 37;

[0047] GnRH 100 ug / animal per injection;

[0048] PG 0.6 mg / animal per injection;

[0049] A3 25 ug / animal per injection;

[0050] hCG 3000 IU / animal per injection;

[0051] Ketoprofen 10 ml / animal per injection.

[0052] Preferably, regimen (6) is used.

[0053] In the present application, n ranges from 34 to 37.

[0054] Further, the cow is a 1-4 parity cow.

[0055] Further, the cow is a dairy cow, preferably a Holstein dairy cow.

[0056] Further, the insemination amount is 0.25 ml of semen, and the effective sperm amount per input is not less than 12 million.

[0057] The time of the cow pregnancy examination is the 35th day after artificial insemination.

[0058] By the above technical solution, the present application has at least the following advantages and beneficial effects:

[0059] The present application provides a method for improving the efficiency of timed insemination of dairy cows under summer conditions, which uses CIDR, eCG, hCG, ketoprofen and the like to significantly improve the efficiency of timed insemination of dairy cows under heat stress conditions, thereby improving the reproductive performance of dairy cows under summer conditions, and has important economic value and social value for ensuring the healthy development of the dairy farming industry. The present application has the advantages of low cost, simple operation, zero milk discard and the like, and has good popularization prospects. DETAILED DESCRIPTION

[0060] The following examples are used to illustrate the present application, but are not used to limit the scope of the present application. If not specifically indicated, the technical means used in the examples are conventional means known to those skilled in the art, and the raw materials used are commercially available goods.

[0061] The GnRH, PG used in the following examples were purchased from Ningbo Sansheng Biotechnology Co., Ltd., ketoprofen was purchased from Foshan Nanhai East Dragon Pharmaceutical Co., Ltd. (containing 0.15 g of ketoprofen per ml), and CIDR was purchased from Shuoteng Biopharmaceutical Co., Ltd. eCG, hCG, A3 were purchased from Ningbo Sansheng Biotechnology Co., Ltd.

[0062] In the following examples, the injection amount of GnRH was 100 ug per head;

[0063] The injection amount of PG was 0.6 mg per head;

[0064] The injection amount of A3 was 25 ug per head;

[0065] The injection amount of eCG was 500 IU per head;

[0066] The injection amount of hCG was 3000 IU per head;

[0067] The injection amount of ketoprofen was 10 ml per head;

[0068] The insemination volume is 0.25 ml of semen, and the effective sperm volume is not less than 12 million per time.

[0069] The terms in the present application are:

[0070] 0-7-9 single synchronization refers to injecting GnRH on the 34th day after delivery of the cow, injecting PG with an interval of 7 days, injecting GnRH with an interval of 2 days, and performing insemination with an interval of 1 day.

[0071] Insemination refers to artificial insemination (artificial insemination).

[0072] Example 1

[0073] I. Experimental method

[0074] Under the condition of heat stress in summer (June-September, THI>120), choose Chinese Holstein cows with similar parity, body condition and health for experiment. On the 35th day after artificial insemination, B-ultrasound is used for pregnancy detection, and the conception rate is calculated.

[0075] 1. Selection and grouping of cattle, blood sampling

[0076] Select 1-4 parity cows for the test, and randomly divide the treated cattle in each batch into 4 groups for operation until each group of test cattle reaches more than 30. Blood is collected on the 1st, 5th, 8th, 11th and 14th day after insemination, and the serum is collected and stored in liquid nitrogen for metabolome sequencing. Fresh feces (soft) 2-3 grams are collected from the end of the rectum on the day of insemination, placed in a 2ml cryopreservation tube, and stored in liquid nitrogen for intestinal microbiota sequencing.

[0077] 2. Experimental treatment

[0078] “0-7-9” optimization experiment treatment:

[0079] (1) GnRH+PG+GnRH group: local normal regular insemination program (0-7-9 single synchronization). Inject GnRH on the 34th day after delivery, inject PG with an interval of 7 days, inject GnRH with an interval of 2 days, and perform insemination with an interval of 1 day.

[0080] (2) GnRH+CIDR+PG+GnRH+hcG group: inject GnRH on the 34th day after delivery, and simultaneously implant CIDR; remove the CIDR after an interval of 7 days, inject PG; inject GnRH after an interval of 2 days; perform insemination after an interval of 1 day; inject hCG 5 days after insemination.

[0081] (3) GnRH+CIDR+PG+eCG+GnRH group: inject GnRH on the 34th day after delivery, and simultaneously implant CIDR; remove the CIDR after an interval of 7 days, inject PG and eCG; inject GnRH after an interval of 2 days; perform insemination after an interval of 1 day.

[0082] (4) GnRH + CIDR + PG + eCG + GnRH + hcG group: GnRH injection on the 34th day after delivery, while embedding CIDR; CIDR was removed after 7 days, PG and eCG were injected; GnRH was injected after 2 days; insemination was performed after 1 day; hCG was injected 5 days after insemination.

[0083] (5) GnRH + CIDR + PG + eCG + GnRH + hcG + ketoprofen group: GnRH injection on the 34th day after delivery, while embedding CIDR; CIDR was removed after 7 days, PG and eCG were injected; GnRH was injected after 2 days; insemination was performed after 1 day; hCG was injected 5 days after insemination, and ketoprofen (10 ml / time / head) was injected at night on the 15th day and in the morning on the 16th day after insemination.

[0084] “0-7-8-9” optimization experiment treatment:

[0085] (1) GnRH + PG + PG + GnRH: GnRH injection on the 34th day after delivery, PG injection after 7 days and 8 days, GnRH injection after 1 day, and insemination after 1 day;

[0086] (2) GnRH + PG + PG + GnRH + A3 + hCG: GnRH injection on the 34th day after delivery; PG injection after 7 days and 8 days, GnRH injection after 1 day; insemination after 1 day, A3 injection at the same time, hCG injection 5 days after insemination.

[0087] (3) GnRH + PG + PG + GnRH + A3 + hCG + ketoprofen: GnRH injection on the 34th day after delivery; PG injection after 7 days and 8 days, GnRH injection after 1 day; insemination after 1 day, A3 injection at the same time, hCG injection 5 days after insemination, and ketoprofen (10 ml / time / head) injection at night on the 15th day and in the morning on the 16th day after insemination.

[0088] II. Experimental results

[0089] 1. Comparison of 0-7-9 single synchronization and different optimization methods under hot stress conditions in summer

[0090] As shown in Table 1, the pregnancy rate of GnRH+CIDR+PG+eCG+GnRH+hcG+ketoprofen group (52.67±4.87%) was the highest, which was significantly higher than that of all other groups. The pregnancy rates of 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, which were significantly higher than that of GnRH+PG+GnRH group (9.17±0.85%).

[0091] Table 1 Comparison of different optimization methods of 0-7-9 single synchronization under summer heat stress conditions

[0092]

[0093] Note: The superscript letters indicate significant differences.

[0094] 2. Comparison of different optimization methods of 0-7-9 single synchronization under summer heat stress conditions

[0095] As shown in Table 2, the timed insemination efficiency of GnRH+PG+PG+GnRH+A3+hCG group (58.43±5.34%) was significantly higher than that of GnRH+PG+PG+GnRH group (31.46±4.06%).

[0096] Table 2 Comparison of different optimization methods of 0-7-8-9 single synchronization under summer conditions

[0097]

[0098] 3. Comparison of optimization methods of 0-7-9 and 0-7-8-9 under summer heat stress conditions

[0099] As shown in Table 3, the timed insemination efficiency of GnRH+PG+PG+GnRH+A3+hCG+ketoprofen group (65.22±7.43%) was significantly higher than that of GnRH+PG+PG+GnRH+A3+hCG group (57.43±4.58%) and GnRH+CIDR+PG+eCG+GnRH+hcG+ketoprofen group (52.68±5.04%).

[0100] Table 3 Comparison of timed insemination efficiency of different single synchronization optimization procedures

[0101]

[0102] In summary, under summer heat stress conditions, the GnRH+PG+PG+GnRH+A3+hCG+ketoprofen program can significantly improve the timed insemination efficiency of dairy cows.

[0103] Although the present application has been described in detail with general principles and specific embodiments, modifications or improvements can be made on the basis of the present application, which is obvious to those skilled in the art. Therefore, these modifications or improvements made on the basis of not deviating from the spirit of the present application, all belong to the scope of the present application claimed.

[0104] Reference:

[0105] 1、Aguiar LH, Hyde KA, Pedroza GH, et al. Heat stress impairs in vitrodevelopment of preantral follicles of cattle[J]. Anim Reprod Sci, 2020, 213:106277.

[0106] 2、Bouroutzika E, Kouretas D, Papadopoulos S, et al. Effects ofMelatonin Administration to Pregnant Ewes under Heat-Stress Conditions, inRedox Status and Reproductive Outcome[J]. Antioxidants (Basel), 2020, 9(3):266.

[0107] 3、Collier RJ, Dahl GE, VanBaale MJ. Major advances associated withenvironmental effects on dairy cattle[J]. J Dairy Sci, 2006, 89(4): 1244-1253.

[0108] 4Chang-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.

[0109] 5Chen 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.

[0110] 6Cebrian-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.

[0111] 7Del Corvo M, Lazzari B, Capra E, et al. Methylome Patterns of Cattle Adaptation to Heat Stress[J]. Front Genet, 2021, 12: 633132.

[0112] 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.

[0113] 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.

[0114] 10. Garcia-Ispierto I, Abdelfatah A, López-Gatius F. Melatonin treatment 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.

[0115] 11. Kamal R, Dutt T, Patel M, et al. Heat stress and effect of shade materials on hormonal and behavior response of dairy cattle: a review [J]. Trop Anim Health Prod, 2018, 50(4): 701-706.

[0116] 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.

[0117] 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.

[0118] 14、Ouellet V, BoucherA, Dahl GE, et al. Consequences of maternal heatstress 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 in dairy cows under summer conditions, characterized in that, The following approach can be used to improve the efficiency of timed insemination in dairy cows under summer conditions; The proposed scheme is a combination of GnRH+PG+PG+GnRH+LHRH-A3+hCG+ketoprofen: The cow was given the first injection of GnRH on day n postpartum; PG was injected once on day n+7 and day n+8; GnRH was injected a second time on day n+8+1; artificial insemination was performed on day n+8+1+1, and LHRH-A3 was injected at the same time; hCG was injected on day 5 postpartum; ketoprofen was injected once on the evening of day 15 and once on the morning of day 16 postpartum. Where n ranges from 34 to 37; The dosage of GnRH is 100ug / head per injection; The dosage of PG is 0.6 mg per head per injection; The dosage of LHRH-A3 is 25ug per head per injection; The hCG injection dose is 3000 IU / head per dose; The dosage of ketoprofen is 10 ml per head per injection.

2. The method according to claim 1, characterized in that, The cattle in question are cows that have given birth 1-4 times.

3. The method according to claim 1, wherein the insemination volume is 0.25 ml of semen, and the effective sperm count in each insemination is not less than 12 million.

4. The method according to claim 1, characterized in that, The time for checking gestation in cattle is 35 days after artificial insemination.

5. The method according to any one of claims 1-4, characterized in that, The cow in question is a Holstein dairy cow.

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