CN114601039A - A method for improving estrus rate and conception rate of sheep under heat stress - Google Patents

Abstract

The invention discloses a method for improving the oestrus rate and the conception rate of sheep under heat stress. Adding 0.05-0.2% of cholesterol substances into sheep feed or water, and feeding sheep ewes from before estrus to 30 days after hybridization in high-temperature seasons. According to the invention, 0.2g-1.0 g/one day of cholesterol is added into the ewe feed or drinking water in the period from the high-temperature season before estrus to 30 days after hybridization, so that the influence of heat stress on the estrus rate and the hybridization rate of sheep can be obviously relieved, and the economic benefit of a farm is improved.

Description

A method for improving estrus rate and conception rate of sheep under heat stress

technical field

The invention belongs to the field of animal breeding, and relates to a method for improving the estrus rate and the conception rate of sheep under heat stress.

Background technique

With the development of sheep farming intensification and global warming, the adverse effects of heat stress on sheep reproductive performance are becoming more and more serious. Heat stress affects late oocyte development in sheep (Ahmadi E et al; 2019), embryonic development and implantation, pregnancy maintenance, and fetal development, manifesting as prolonged estrus cycle, decreased conception rate and embryo survival rate (Gharibzadeh Z et al, 2015; Macías-Cruz U et al, 2016; Romo-Barron CB et al, 2019). Romo-Barron CB et al. (2019) conducted a meta-analysis of 48 experiments from 36 studies and showed that heat stress made ewes less estrus, shortened estrus duration by 7.09 hours, prolonged estrus cycle by 0.57 days, and decreased pregnancy rate by 58.8%. , the embryo mortality rate was 12.36 times that of the normal control group. In addition, the weight of the placenta was significantly reduced (-183.62g), and the birth weight of the lambs was reduced by 0.99kg, all of which were significantly different from the control group (P<0.05). Generally speaking, the suitable temperature for sheep is 21°C-25°C, if the ambient temperature is too high, heat stress will occur. With the gradual increase in global temperature and the intensive and large-scale development of sheep farming, the heat stress of sheep is becoming more and more serious, which brings huge economic losses to the farming industry.

Cholesterol is an important component of cell membranes, accounting for more than 20% of plasma membrane lipids. At high temperature, cholesterol can prevent the disorder of the plasma membrane bilayer, and at low temperature, it can prevent the formation of crystals, maintain its fluidity, and maintain the stability of the plasma membrane structure. At the same time, cholesterol is the precursor substance for the synthesis of steroid hormones (sex hormones and adrenocortical hormones). The imbalance of cholesterol homeostasis can also affect the synthesis of progesterone and estrogen by affecting the expression of ovarian luteinizing hormone receptors. However, there is no report on the effect of cholesterol supplementation on the estrus rate and conception rate of sheep by relieving heat stress.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide the application of cholesterol in the preparation of additives or feeds for relieving the influence of heat stress on the estrus rate and conception rate of sheep, aiming at the above-mentioned deficiencies of the prior art.

Another object of the present invention is to provide a method for increasing the estrus rate and conception rate of sheep under heat stress.

Yet another object of the present invention is to provide a sheep feed.

The object of the present invention can be realized through the following technical solutions:

The application of cholesterol substances in the preparation of additives or feeds for relieving the effects of heat stress on the estrus rate and conception rate of sheep.

As a preference of the present invention, the added amount of the cholesterol substances is 0.2 g to 1.0 g per ewe per day.

As a preference of the present invention, the cholesterol substance is cholesterol or a cholesterol derivative with cholesterol activity.

A method for improving the estrus rate and conception rate of sheep under heat stress. Cholesterol substances are added to sheep feed or drinking water in an additive amount of 0.05% to 0.2%, and they are fed in the estrus period, estrus period or breeding in high temperature seasons. Sheep ewes up to 30 days after breeding.

As a preference of the present invention, the sheep feed is selected from the group consisting of complete mixed rations, complete pellets, concentrates, concentrated feeds, premixes or feed raw materials.

As a preference of the present invention, the amount of the supplementary cholesterol substances is 0.2 g to 1.0 g per ewe per day.

As a preference of the present invention, the cholesterol substance is cholesterol or a cholesterol derivative with cholesterol activity.

A sheep feed, the sheep feed is 0.05% to 0.2% of cholesterol substances added to the basic feed.

As a preference of the present invention, the basic feed is selected from the group consisting of complete mixed rations, complete pellets, concentrates, concentrates, premixes or feed materials.

As a preference of the present invention, the cholesterol substance is cholesterol or a cholesterol derivative with cholesterol activity.

Beneficial effects:

With the development of sheep farming intensification and global warming, the adverse effects of heat stress on sheep reproductive performance are becoming more and more serious. Heat stress affects the late development of sheep oocytes, embryonic development and implantation, pregnancy maintenance, and fetal development, manifested as prolonged estrus cycle, decreased conception rate and embryo survival rate. The present invention chooses to add 0.2g-1.0g/day* of cholesterol to sheep ewe feed or drinking water during the period of time before estrus to 30 days after breeding in high temperature season, which can significantly alleviate heat stress on sheep estrus rate and sheep estrus rate. The influence of the breeding rate can significantly increase the estrus rate and conception rate of sheep, and improve the economic benefits of the farm.

Description of drawings

Figure 1 Total cholesterol levels in the serum of experimental sheep in different groups at 0h, 2h, 4h, 8h, 12h, 24h, 48h, 96h and 120h after feeding cholesterol

Figure 2. Total cholesterol content in serum of Hu sheep at different time points after cholesterol supplementation

Detailed ways

The test methods mentioned in the following examples are conventional methods unless otherwise specified. The total cholesterol assay kit was purchased from Nanjing Jiancheng Bioengineering Co., Ltd., and the estradiol and progesterone assay kits were purchased from Beijing Northern Institute of Biotechnology. Co., Ltd., and feed-grade cholesterol was purchased from Zhengzhou Cangyu Food Chemical Co., Ltd. Embodiment 1, supplementary feeding cholesterol in summer improves cholesterol level in Hu sheep serum (1) Materials and methods:

(1) Preparation of feed required for the example: add 0.1% and 0.5% cholesterol to Hu sheep feed, the feed composition is 39.0% corn, 4.3% bran, 5.0% rice bran, 9.0% soybean meal, 3.0% corn DDGS, 3.0% corn germ soybean meal, 32.0% peanut stalk meal, 3.0% Zhengchang premix (fattening), 1.0% baking soda, 0.7% stone meal; the control group feed did not contain cholesterol.

(2) 60 multi-bred Hu sheep ewes came from Liuhe Animal Base of Jiangsu Academy of Agricultural Sciences, healthy and non-pregnant. Randomly divided into 3 groups. The three groups of sheep were respectively fed with feed without cholesterol (control group), feed with 0.1% cholesterol (0.1% test group) and feed with 0.5% cholesterol (0.5% test group).

(3) Three groups of sheep were collected blood before feeding, 2h, 4h, 8h, 12h, 24h, 48h, 96h and 120h after feeding, and serum was separated. ELISA was used to detect the total cholesterol levels in the serum of sheep in different groups.

(2) Results and Analysis

(1) Cholesterol supplementation significantly increased the serum total cholesterol level of Hu sheep. The serum total cholesterol level of Hu sheep in control group, 0.1% experimental group and 0.5% experimental group was detected by ELISA method. The results showed that compared with the control group, the serum total cholesterol content of Hu sheep in the 0.1% experimental group and the 0.5% experimental group gradually increased from 2h to 48h after feeding, and the cholesterol did not increase after 48h until 120h, but the 0.1% experimental group The increase in cholesterol between the 0.5% and 0.5% experimental groups was not significantly different (Figure 1).

Embodiment 2, the method that supplementary feeding cholesterol in summer improves estrus rate and conception rate of Hu sheep

(1) Materials and methods:

(1) The start time of the implementation case test is July 14, 2021, and the end time is September 14, 2021. The average temperature in Taicang City, Suzhou City, Jiangsu Province is higher than 25℃.

(2) Preparation of feed required for the example: add 0.1% cholesterol to Hu sheep feed, the feed composition is 39.0% corn, 4.3% bran, 5.0% rice bran, 9.0% soybean meal, 3.0% corn DDGS, 3.0% Corn germ soybean meal, 32.0% peanut straw meal, 3.0% Zhengchang premix (fattening), 1.0% baking soda, 0.7% stone powder, pressed into pellets with a diameter of 6mm; the control group feed was a diameter without 0.1% cholesterol For 6mm pellet feed.

(3) 78 multi-bred Hu sheep ewes from Donglin Experimental Sheep Farm, Taicang City, Jiangsu Province, were healthy and non-pregnant. Randomly divided into 2 groups, the two groups of Hu sheep ewes were treated with conventional estrus method, that is, the sheep were placed into the sheep's vagina with vaginal suppository, and taken out on the 13th day after placement, and immediately intramuscularly injected prostaglandin 1ml/sheep. On the day of estrus treatment at the same time, the two groups of sheep were fed with cholesterol-free feed and cholesterol-added feed, respectively, named as the control group and the cholesterol supplemented feed group; each sheep in the two groups was fed 500 g of pelleted feed every day, and the cholesterol supplemented feed group was fed with 500 g of pelleted feed every day. The amount of cholesterol supplemented for sheep every day is 0.5g

(4) The estrus situation of Hu sheep treated in the same estrus period was not counted in the first estrus cycle, and the estrus rates of the two groups were counted in the next natural estrus cycle. The same semen was used for artificial insemination and breeding of ewes in the control group and cholesterol supplementation group, and the progesterone content in serum was detected 30 days after breeding, and the conception rate of Hu sheep in the two groups was judged accordingly.

(5) Significant differences in estrus rate and conception rate between the control group and the supplementary feeding group were analyzed using the One-way ANOVA method in SPSS19.0.

(2) Results and analysis

(1) The cholesterol content in serum of the cholesterol supplementation group was significantly increased

The Hu sheep ewes in the control group and the cholesterol supplemented feeding group were treated with estrus treatment at the same time, and the sheep in the cholesterol supplemented feeding group were respectively collected blood before supplementary feeding, on the 3rd day and on the 30th day of supplementary feeding to separate serum. Changes in serum cholesterol levels were detected with a total cholesterol assay kit. The results (Figure 2) found that compared with before supplementation, the serum cholesterol content of Hu sheep on the third and 30th day after supplementation with cholesterol was significantly increased (P<0.01);

(2) Cholesterol supplementation increases the estrus rate of Hu sheep

The Hu sheep and ewes in the control group and the cholesterol supplemented feeding group were used for estrus identification on the 32nd to 34th day after the estrus treatment in the same period. The rate is 7.6% higher.

(3) Cholesterol supplementation significantly increased the conception rate of Hu sheep

Results 2 Hu sheep ewes in estrus were treated with artificial insemination, and blood was collected 30 days later to separate serum. ELISA was used to detect the serum progesterone content of Hu sheep in the control group and cholesterol supplemented feeding group to confirm the conception rate. The results showed that compared with the control group, the conception rate of Hu sheep in the cholesterol supplementation group increased by 16.7%.

Table 1 Effects of supplemental cholesterol on estrus rate and conception rate of Hu sheep

control group test group natural heat rate 82.7% 89.1% conception rate 46.9% ^a 63.6% ^b

Claims (10)

1. Application of cholesterol substances in preparing additives or feeds for relieving influence of heat stress on oestrus rate and conception rate of sheep.

2. The use according to claim 1, characterized in that the cholesterol substances are added in an amount of 0.2-1.0 g per ewe per day.

3. Use according to claim 1, characterized in that the cholesterol-like substance is cholesterol or a cholesterol derivative having cholesterol activity.

4. A method for improving the oestrus rate and the conception rate of sheep under heat stress is characterized in that cholesterol substances are added into sheep feed or drinking water in an adding amount of 0.05-0.2%, and the sheep ewes are fed in the oestrus period, the oestrus period or the period from hybridization to hybridization for 30 days in a high-temperature season.

5. The method as claimed in claim 1, wherein the sheep feed is selected from the group consisting of a complete mixed ration, a complete pellet, a concentrate feed, a premix feed and a feedstuff.

6. The method according to claim 1, wherein the amount of said supplementary feeding cholesterol is between 0.2 and 1.0g per ewe per day.

7. The method of claim 1, wherein the cholesterol is cholesterol or a cholesterol derivative having cholesterol activity.

8. The sheep feed is characterized in that 0.05-0.2% of cholesterol substances are added into a basic feed.

9. The sheep feed according to claim 8, wherein the basal feed is selected from the group consisting of a complete mixed ration, a complete pellet, a concentrate, a premix, and a feedstuff.

10. The sheep feed according to claim 1, characterized in that said cholesterol is cholesterol or a cholesterol derivative having cholesterol activity.

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