A method for improving reproductive performance and lactation performance of postpartum dairy cows

Abstract

The invention discloses the use of tryptophan in preparing a medicine and a feed additive for improving the reproductive performance and lactation performance of postpartum dairy cows. The invention also discloses a method for improving the reproductive performance and lactation performance of postpartum dairy cows by feeding tryptophan during the peripartum period. The method of the invention can improve the anti-inflammatory and antioxidant properties of dairy cows, reduce the incidence of diseases after delivery of dairy cows, increase the breeding pregnancy rate of dairy cows after delivery, increase the content of immunoglobulin A in colostrum secreted by dairy cows after delivery, and adjust the gestation days of dairy cows to about 280 days and increase the daily milk production in the early lactation period.

Description

Technical Field

[0001] The invention relates to the field of agricultural animal husbandry, and in particular to a method for improving the reproductive performance and lactation performance of postpartum dairy cows. Background Art

[0002] The peripartum period of dairy cows generally refers to the period from 21 days before delivery (late pregnancy) to 21 days after delivery (early lactation), of which 3 weeks before delivery belongs to the early peripartum period and 3 weeks after delivery belongs to the late peripartum period. During the peripartum period, the nutritional requirements of dairy cows increase sharply because they have to meet the rapid growth and development of the fetus and start the secretion of colostrum. However, due to the fetus's occupation of abdominal space and endocrine changes, the dry matter intake of cows decreases, thereby reducing the energy intake level. These reasons together lead to the fact that the energy intake of cows through feeding during the peripartum period cannot meet the needs of fetal growth and development and lactation, thus resulting in a negative energy balance. In order to make up for the body's negative energy balance, dairy cows will actively mobilize body fat and mobilize a large amount of body reserves at this time. Adipose tissue releases a large amount of non-esterified fatty acid (NEFA) into the liver for oxidation and energy supply, but the excess NEFA will be incompletely oxidized in the liver to produce ketone bodies with β-hydroxybutyric acid (BHBA) as the main form. Excessive accumulation of ketone bodies will induce ketosis. Excessive body fat mobilization may bring a series of negative problems, including increasing the metabolic burden of the liver, causing oxidative stress, reducing the immune function of dairy cows, and increasing the probability of metabolic diseases. Therefore, peripartum management of cows and supplementation of nutrients are particularly important.

[0003] Therefore, exploring a method to improve reproduction and lactation in postpartum dairy cows is crucial for periparturient dairy cows. Summary of the invention

[0004] In order to solve one of the above technical problems existing in the prior art, the present invention provides a method for improving the reproductive performance and lactation performance of postpartum dairy cows by feeding tryptophan in the pre-peripartum period.

[0005] In a first aspect, the present invention provides use of tryptophan in preparing a medicine and / or a feed additive for improving reproductive performance and / or lactation performance of postpartum dairy cows.

[0006] Tryptophan (Trp), chemical name is L-2-amino-3 (β-indole) propionic acid (C 11 H 12 N2O2), can serve as a substrate for protein synthesis, participate in the renewal of plasma proteins in animals, promote the role of riboflavin, and contribute to the synthesis of niacin and heme.

[0007] The present invention unexpectedly discovered through animal experiments that tryptophan can improve the reproductive performance and lactation performance of postpartum dairy cows.

[0008] In some embodiments, improving the reproductive performance of postpartum dairy cows comprises one or more of regulating reproductive hormone levels, increasing postpartum breeding pregnancy rates, and reducing the incidence of postpartum diseases.

[0009] In some embodiments, the reproductive hormones include, but are not limited to, serum follicle-stimulating hormone and serum luteinizing hormone.

[0010] In some embodiments, the postpartum disease comprises one or more of retained afterbirth, metritis, mastitis, limb disease, and postpartum paralysis.

[0011] In some embodiments, the postpartum disease is metritis.

[0012] In some embodiments, improving the lactation performance of postpartum dairy cows comprises one or more of increasing the level of colostrum immunoglobulin, increasing daily milk production, increasing the lactose rate of milk, reducing the milk fat rate of milk, and regulating the gestation days of dairy cows.

[0013] In some embodiments, feeding tryptophan can adjust the gestational days of dairy cows to 280±2 days, preferably to 280±1 days. The gestational days of dairy cows are related to lactation performance. When the gestational days of dairy cows are around 280 days (280±2 days), their overall lactation index is the best. Too high or too low gestational days will have a negative impact on lactation performance, and too low gestational days will have a relatively greater impact.

[0014] In some embodiments, the tryptophan of the present invention is L-tryptophan.

[0015] In a second aspect, the present invention provides a method for improving the reproductive performance and / or lactation performance of postpartum dairy cows, the method comprising feeding tryptophan from 26±2 days before the cows give birth to the cows. Preferably, feeding tryptophan to the dairy cows starts about one week in advance of the pre-perinatal period, so that the dairy cows are in a high tryptophan state when they enter the peripartum period.

[0016] The feeding method can be direct feeding or adding it to the dairy cow's diet. For example, tryptophan can be added to the total mixed ration (TMR) of dairy cows.

[0017] In some embodiments, the method comprises feeding tryptophan to the cow from day 28 prepartum until the cow parturition.

[0018] In some embodiments, tryptophan can be directly added to the feed of periparturient dairy cows, which is easy to operate and does not require injection or implantation, thereby avoiding stress reactions in dairy cows.

[0019] In some embodiments, only tryptophan is added to the dietary feed of dairy cows.

[0020] In some embodiments, the amount of tryptophan added is 1.5%-4% of the dairy cow's diet, for example, it can be 1.5%, 1.67%, 2.0%, 2.5%, 3.0%, 3.33%, 3.5% or 4.0%.

[0021] In some embodiments, the daily dose of tryptophan is 50-100 g / day, for example, 50 g / day, 60 g / day, 70 g / day, 80 g / day, 90 g / day or 100 g / day.

[0022] In some embodiments, the cow is a multiparous cow.

[0023] In some embodiments, the cow takes tryptophan for 2-5 parities.

[0024] In some embodiments, the tryptophan of the present invention is L-tryptophan.

[0025] The beneficial effects of the present invention are:

[0026] The present invention surprisingly found that the reproductive performance and lactation performance of postpartum dairy cows were improved by adding tryptophan to the complete mixed diet of dairy cows in the early peripartum period. The present invention found that feeding tryptophan in the early peripartum period can improve the anti-inflammatory and antioxidant properties of dairy cows, reduce the incidence of diseases after delivery of dairy cows, increase the breeding pregnancy rate of dairy cows after delivery, increase the content of immunoglobulin A in colostrum secreted by dairy cows after delivery, and adjust the gestation days of dairy cows to about 280 days and increase the daily milk production in the early lactation period. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 The effect of feeding L-tryptophan on the tryptophan levels in serum and milk of dairy cows is shown. Wherein, (A) serum tryptophan content; (B) tryptophan content in milk. "Before feeding" indicates the sampling before the dairy cows were fed L-tryptophan, -21, -14 and -7 indicate the days before the dairy cows gave birth; 1, 4, 7, 14 and 21 indicate the days after the dairy cows gave birth. The dotted line indicates the time when the dairy cows calved, which is also the time when the L-tryptophan feeding was stopped.

[0028] Figure 2 The effect of feeding L-tryptophan in the peripartum period on serum glucose and lipid metabolism in dairy cows is shown. Among them, (A) serum NEFA content; (B) serum BHBA content; (C) serum GLU content; (D) serum TG content; (E) serum TC content; (F) serum VLDL content.

[0029] Figure 3The effect of feeding L-tryptophan in the peripartum period on the immune and antioxidant properties of dairy cows is shown. Among them, (A) serum COR content; (B) serum MDA content; (C) serum SOD content; (D) serum T-AOC level; (E) serum IL-6 content; (F) serum IL-10 content.

[0030] Figure 4 The effect of feeding L-tryptophan on the reproductive performance of dairy cows is shown. Among them, (A) serum E2 content; (B) serum P4 content; (C) serum FSH content; (D) serum LH content.

[0031] Figure 5 The effect of feeding L-tryptophan in the peripartum period on immunoglobulins in colostrum is shown. (A) Colostrum IgG content; (B) Colostrum IgM content; (C) Colostrum IgA content.

[0032] Figure 6 The effect of feeding L-tryptophan in the peripartum period on daily milk production and milk components is shown. Among them, (A) daily milk production; (B) milk lactose rate; (C) milk fat rate.

[0033] Figure 7 The effect of feeding L-tryptophan during the pre-peripartum period on the length of gestation is shown. DETAILED DESCRIPTION

[0034] In order to make the purpose, technical scheme and advantages of the present invention clearer, the present invention is further described in detail below in conjunction with embodiments. The specific embodiments described herein are only used to explain the present invention and are not intended to constitute any limitation of the present invention. In addition, in the following description, the description of known structures and technologies is omitted to avoid unnecessary confusion of the concepts of the present disclosure. Such structures and technologies are also described in many publications.

[0035] definition

[0036] Unless otherwise defined, all technical and scientific terms used in the present invention have the same meaning as commonly used in the field to which the present invention belongs. For the purpose of interpreting this specification, the following definitions will apply, and where appropriate, terms used in the singular will also include the plural form, and vice versa.

[0037] Unless the context clearly dictates otherwise, the expressions "a", "an" and "an" as used herein include plural references. For example, reference to "a cell" includes a plurality of such cells and equivalents thereof known to those skilled in the art, and so forth.

[0038] As used herein, the term "about" refers to a range of ±20% of the value that follows. In some embodiments, the term "about" refers to a range of ±10% of the value that follows. In some embodiments, the term "about" refers to a range of ±5% of the value that follows.

[0039] The term "peripartum period" as used herein refers to the period from 21 days before parturition (late gestation) to 21 days after parturition (early lactation) of a dairy cow, wherein the 3 weeks before parturition belong to the early peripartum period and the 3 weeks after parturition belong to the late peripartum period.

[0040] Examples and drawings are provided below to help understand the present invention. However, it should be understood that these examples and drawings are only used to illustrate the present invention, but do not constitute any limitation. The actual protection scope of the present invention is set forth in the claims. It should be understood that any modifications and changes can be made without departing from the spirit of the present invention.

[0041] The reagents and materials used in the following examples are all commercially available products. L-tryptophan (Trp) was purchased from Xi'an Musen Biotechnology Co., Ltd.

[0042] The total mixed ration (TMR) for dairy cows in the following examples mainly includes:

[0043]

[0044] Example 1. Experimental animals and experimental methods

[0045] 135 healthy cows about to enter the peripartum period with basically the same physical condition were selected, with an average body weight of 700kg, and were randomly divided into 3 groups, each with 45 cows, namely a control group, a 50g Trp test group and a 100g Trp test group. Two test groups added L-tryptophan to TMR at 5:00 a.m. every day, and the addition amount was such that each cow took in 50g and 100g L-tryptophan on average every day. In the following examples, L-tryptophan was added from the 26th ± 2nd day before the birth of the cow, so that the cow was in a high tryptophan state when entering the pre-perinatal period, and the addition was stopped after the cow gave birth. During the test period, milk and blood samples were collected every 7 days for subsequent detection.

[0046] Blood processing method before testing: whole blood of dairy cows is collected by tail vein blood sampling, and the whole blood is centrifuged at 3000r / min for 10min to obtain serum, which is then frozen at -20℃ for testing.

[0047] Determination of tryptophan levels in bovine serum and milk: Determination by liquid chromatography-mass spectrometry.

[0048] Determination of serum glucose and lipid metabolism related indicators: Glucose, triglyceride and total cholesterol levels were measured using ZY-1280 fully automatic biochemical analyzer (Shanghai Kehua Bioengineering Co., Ltd.). Non-esterified fatty acids, β-hydroxybutyric acid and very low-density lipoprotein in serum were detected by enzyme-linked immunosorbent assay (ELISA).

[0049] Determination of immune and antioxidant performance-related indices: Cortisol, interleukin-6, and interleukin-10 were detected by enzyme-linked immunosorbent assay (ELISA), and malondialdehyde, superoxide dismutase, and total antioxidant capacity levels were determined using L-3180 semi-automatic biochemical analyzer (Shanghai Kehua Bioengineering Co., Ltd.).

[0050] Determination of reproductive hormone indicators: estradiol, progesterone, luteinizing hormone and follicle-stimulating hormone were detected by enzyme-linked immunosorbent assay (ELISA).

[0051] Example 2. Effect of feeding L-tryptophan in the peripartum period on the levels of tryptophan in serum and milk of dairy cows

[0052] After feeding L-tryptophan to dairy cows in the peripartum period, compared with before feeding, the serum tryptophan levels of dairy cows in the 50g Trp experimental group and the 100g Trp experimental group before delivery ( Figure 1 A) levels tended to increase, and the tryptophan levels in the colostrum of the two experimental groups (day 1) were higher than those in the control group ( Figure 1 B).

[0053] This suggests that feeding L-tryptophan during the periparturient period can increase the prepartum serum tryptophan level and the tryptophan level in colostrum of dairy cows.

[0054] Example 3. Effect of feeding L-tryptophan during the peripartum period on serum glucose and lipid metabolism in dairy cows

[0055] On the 14th day after delivery, serum non-esterified fatty acids (NEFA) ( Figure 2 A) and β-hydroxybutyrate (BHBA) ( Figure 2 B) level was significantly lower than that in the control group (p < 0.05). Figure 2 C) and total cholesterol (TC) ( Figure 2 E) was lower than the control group, and the triglyceride (TG) ( Figure 2 D) and very low density lipoprotein (VLDL) ( Figure 2 F) No significant increase was observed.

[0056] This suggests that feeding L-tryptophan in the early peripartum period plays a certain role in alleviating the negative energy balance of dairy cows during the peripartum period.

[0057] Example 4. Effects of feeding L-tryptophan during the peripartum period on the immune and antioxidant properties of dairy cows

[0058] Feeding L-tryptophan in the peripartum period, from 28 days before delivery (-28d) to 7 days before delivery (-7d), the serum cortisol (COR) levels of the 50g Trp test group and the 100g Trp test group were lower than those of the control group ( Figure 3 A), which indicates that feeding tryptophan makes dairy cows less stressed. The malondialdehyde (MDA) content of the 100g Trp test group decreased significantly at -14d, -7d and 0d (p<0.05) ( Figure 3 B). The superoxide dismutase (SOD) activity of the 100g Trp test group was significantly higher than that of the control group at -14d, -7d and 0d, while the SOD of the 50g Trp test group was significantly increased only at 0d (p<0.05) ( Figure 3 C). Total antioxidant capacity (T-AOC) of the 100g Trp test group ( Figure 3 D) and interleukin-10 (IL-10) levels ( Figure 3 F) was significantly higher than the control group at -14d and -7d. The IL-6 level of the 100g Trp test group decreased significantly at -14d and -7d (p<0.05) ( Figure 3 E).

[0059] This indicates that feeding L-tryptophan in the early peripartum period can improve the anti-inflammatory and antioxidant properties of dairy cows and help improve the immunity of dairy cows.

[0060] Example 5. Effect of feeding L-tryptophan during the peripartum period on reproductive performance of dairy cows

[0061] 1. Reproductive hormones

[0062] In the peripartum period, feeding L-tryptophan can significantly reduce the serum estradiol (E2) and progesterone (P4) levels of dairy cows. Figure 4 A, 4B) are relatively consistent and consistent with physiological laws. At 14 days postpartum, the serum follicle-stimulating hormone (FSH) content in the 100g Trp test group was significantly higher than that in the control group (p<0.05) ( Figure 4 C), 14 days before delivery, the serum luteinizing hormone (LH) level in the 50g Trp test group was significantly higher than that in the control group (p<0.05) ( Figure 4 D).

[0063] This indicates that feeding L-tryptophan during the peripartum period can regulate reproductive hormone levels and has no adverse effects on the pregnancy and delivery stages of dairy cows.

[0064] 2. Postpartum breeding pregnancy rate

[0065] The effect of feeding L-tryptophan in the pre-peripartum period on the pregnancy rate of postpartum mating in dairy cows is shown in Table 1. The pregnancy rate of the first mating and the cumulative pregnancy rate of the two matings in the 100g Trp test group were the highest, which were 22.22% (10 / 45) and 44.44% (20 / 45), respectively. The cumulative pregnancy rate of the two matings was significantly higher than that of the control group (p<0.05). The cumulative pregnancy rate of the two matings in the 50g Trp test group was higher than that in the control group. The experimental results show that feeding L-tryptophan in the pre-peripartum period can improve the pregnancy rate of postpartum mating in dairy cows, which provides a reference for solving the problem of low pregnancy rate in the second mating of dairy cows after delivery.

[0066] Table 1 Pregnancy rate of postpartum dairy cows

[0067]

[0068] Note: Different letters indicate significant differences (p<0.05), and the same letters indicate no significant differences.

[0069] 3. Occurrence of postpartum diseases

[0070] Among the postpartum diseases of dairy cows, retained placenta, metritis, mastitis, limb and hoof disease and postpartum paralysis are common diseases, among which metritis is the most common disease. This experiment investigated the effect of feeding L-tryptophan in the early peripartum period on postpartum diseases of dairy cows, and the results are shown in Table 2. Compared with the control group, the incidence of dairy cows in the 50g Trp test group and the 100g Trp test group was significantly reduced, about half of the control group, and the overall incidence of dairy cows in the 100g Trp test group was significantly lower than that in the control group (p < 0.05). The 50g Trp test group also had a trend of reducing the incidence of postpartum diseases, especially the incidence of metritis was significantly reduced.

[0071] Table 2 Occurrence of postpartum diseases in dairy cows

[0072]

[0073] Note: Different letters indicate significant differences (p<0.05), and the same letters indicate no significant differences.

[0074] Example 6. Effect of feeding L-tryptophan during the peripartum period on the level of immunoglobulins in colostrum after delivery

[0075] Feeding L-tryptophan in the early peripartum period increased the levels of immunoglobulins IgG, IgM and IgA in colostrum (day 1) of postpartum dairy cows. Figure 5 A, 5B, 5C), among which the IgA content in the colostrum of the 100g Trp test group was significantly higher than that in the control group (p<0.05) ( Figure 5 C).

[0076] This indicates that feeding L-tryptophan in the early peripartum period can increase the immunoglobulin content in the colostrum of dairy cows, improve the immunity of dairy cows, and help calves establish better passive immunity.

[0077] Example 7. Effect of feeding L-tryptophan during the peripartum period on daily milk production and milk composition of dairy cows

[0078] Feeding L-tryptophan in the peripartum period had a positive effect on milk production. In the second and third weeks after calving, the daily milk production of cows in the 100g Trp test group was significantly higher than that in the control group (p<0.05) ( Figure 6 A). In the third week after delivery, the lactose rate of milk in the 100g Trp test group before delivery was significantly higher than that in the control group, and the milk fat rate was significantly lower than that in the control group (p<0.05) ( Figure 6 B and 6C).

[0079] Due to the prevalence of negative energy balance, higher milk production of dairy cows after calving means more food intake and better condition. The experimental results of the present invention show that after supplementing tryptophan, dairy cows are less affected by negative energy balance, their physical condition recovers better, and the milk quality is higher.

[0080] Example 8. Effect of feeding L-tryptophan during the peripartum period on the gestational days of dairy cows

[0081] Feeding L-tryptophan in the early peripartum period can regulate the gestational days of dairy cows to 280±2 days. The gestational days of dairy cows in the 100g Trp test group were significantly higher than those in the control group (280.8 days vs 275.2 days) (p<0.05). The gestational days of dairy cows in the 50g Trp test group were also higher than those in the control group (278 days vs 275.2 days), approaching 280 days ( Figure 7 ).

[0082] When the gestation period of dairy cows is about 280 days, their overall lactation index is optimal. Too high or too low gestation period will have a negative impact on lactation performance, and too low gestation period has a relatively greater impact. The present invention feeds L-tryptophan in the early peripartum period to adjust the gestation period of dairy cows to about 280 days, which shows that the method of the present invention is conducive to improving the lactation performance of dairy cows after delivery.

[0083] The present invention improves the reproductive performance and lactation performance of postpartum dairy cows by feeding tryptophan in the early peripartum period. The method of the present invention can improve the anti-inflammatory and antioxidant properties of dairy cows, reduce the incidence of diseases after delivery of dairy cows, improve the breeding pregnancy rate of dairy cows after delivery, increase the content of immunoglobulin A in colostrum secreted by dairy cows after delivery, and regulate the gestation days of dairy cows to about 280 days and increase the daily milk production in the early lactation period, which has positive significance for the management of dairy cows in the peripartum period.

[0084] The technical solution of the present invention is not limited to the above-mentioned specific embodiments. All technical variations made according to the technical solution of the present invention fall within the protection scope of the present invention.

Claims

1. Use of tryptophan in the preparation of a medicine and / or feed additive for improving reproductive performance and / or lactation performance of postpartum dairy cows; in, The improving reproductive performance of postpartum dairy cows comprises one or more of increasing the serum follicle-stimulating hormone content and reducing the incidence of postpartum diseases; the postpartum diseases include retained placenta, metritis, limb and hoof disease and postpartum paralysis; and / or, The improving the lactation performance of postpartum dairy cows comprises one or more of increasing the level of colostrum immunoglobulin, increasing the lactose rate of milk, reducing the milk fat rate of milk and regulating the gestation days of dairy cows; The feeding period of the tryptophan is from 26 ± 2 days before the cow gives birth to the cow; the daily dosage of the tryptophan is 50-100 g / day.

2. A method for improving the lactation performance of postpartum dairy cows, characterized in that: The method comprises feeding tryptophan to the cow from 26±2 days before delivery to delivery; the daily dose of tryptophan is 50-100 g / day; The improvement of the lactation performance of postpartum dairy cows includes one or more of increasing the level of colostrum immunoglobulin, increasing the lactose rate of milk, reducing the fat rate of milk and regulating the gestation days of dairy cows.

3. The method according to claim 2, characterized in that The method comprises feeding tryptophan to the dairy cow from the 28th day before calving to the dairy cow calving.

4. The method according to claim 2, characterized in that: The added amount of tryptophan is 1.5%-4% of the daily diet of dairy cows.

5. The method according to any one of claims 2 to 4, characterized in that: The dairy cow is a multiparous dairy cow.

6. The method according to claim 5, characterized in that The dairy cows take tryptophan at parity 2-5.

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