Method for predicting the weight of multi-wave ewes by age

Abstract

The application discloses a method for predicting the body weight of Duolang ewes by age, and belongs to the technical field of animal husbandry. The body height, body slant length, chest depth and chest circumference of the Duolang ewes are measured, and the age information is obtained, the 1-year-old group, the 2-year-old group, the 3-year-old group or the 4-year-old group is determined according to the age, and the corresponding regression equation is selected to calculate the body weight. The optimal prediction model is constructed for different age stages, the rapid and nondestructive evaluation of the body weight is realized, and the data-based reference tool is provided for the age-based feeding management and good seed selection of the Duolang ewes.

Description

Technical Field

[0001] This invention belongs to the field of animal husbandry technology, specifically relating to a method for predicting the weight of Dolane ewes by age. Background Technology

[0002] The Dolan sheep is a superior dual-purpose (meat and fat) sheep breed unique to southern Xinjiang Uygur Autonomous Region. It was officially included in the "National List of Protected Livestock and Poultry Genetic Resources" in 2006. This breed possesses excellent characteristics such as large size, well-developed muscles, large rump, rapid growth, and early sexual maturity, making it a popular local breed among farmers and herders. In meat sheep breeding, body weight is one of the important genetic improvement targets. Body size not only reflects the size, body structure, and organ development of meat sheep, but also has a certain correlation with reproductive performance, growth rate, disease resistance, and environmental adaptability.

[0003] However, traditional weight measurement relies on weighbridges, which can cause stress to sheep during the process of handling them and is inefficient, making it difficult to meet the precision management needs of large-scale farming. Current research has established regression equations based on body size indicators to estimate livestock weight, but the main body size indicators affecting weight dynamically change across different age groups. Existing technologies lack weight estimation schemes that automatically switch between different regression equations based on sheep age, and no weight prediction models for Dolan sheep ewes of different age groups have been reported. Summary of the Invention

[0004] In view of this, the purpose of this invention is to provide a method for predicting the weight of Dolan sheep ewes by age, so as to solve the technical problems of inconvenient measurement of Dolan sheep ewes' weight and low prediction accuracy due to failure to consider age factors in the prior art.

[0005] To achieve the above objectives, the present invention provides the following technical solution: This invention provides a method for age-based prediction of body weight in Dolane ewes, the method comprising the following steps: S1. Measure and record the body size indicators of the Dolan sheep ewes, including body height, body length, chest depth and chest circumference, and obtain the age information of the Dolan sheep ewes at the same time. S2. Determine the age group to which the Dolan sheep ewe belongs based on the age information, wherein the age group is 1 year old, 2 years old, 3 years old or 4 years old; S3. Based on the determined age group, select the corresponding equation from the pre-constructed regression equations to calculate the weight of the Dolan sheep ewes: When the Dolan sheep ewes are 1 year old, the regression equation is: =16.975+0.238X4+0.192X2; When the Dolan sheep ewes are 2 years old, the regression equation is: =2.789 + 0.371X1 + 0.275X2; When the Dolan sheep ewes are 3 years old, the regression equation is: =-4.129+0.779X1; When the Dolan sheep ewes are 4 years old, the regression equation is: =-6.153+0.554X2+0.696X3; in, X1 is the predicted weight value, X2 is the body height, X3 is the body length, X4 is the chest depth, and X5 is the chest circumference.

[0006] Preferably, the body height is the distance from the top of the scapula to the hoof tip; the body length is the distance from the front edge of the shoulder to the ischial tuberosity at the back edge of the buttock; the chest depth is the vertical distance from the highest point of the back to the lowest point of the chest, measured along the back edge of the scapula; and the chest circumference is the circumference measured around the chest along the back edge of the scapula.

[0007] Preferably, the measurements of body height, body length, chest depth, and chest circumference are in centimeters, and the weight is in kilograms.

[0008] Preferably, the Dolan sheep ewes are Dolan sheep ewes aged 1 to 4 years.

[0009] Preferably, the body size index is measured manually or using a 3D intelligent body size measurement system.

[0010] It contains at least the following beneficial technical effects: This invention establishes weight prediction regression equations for Dolan sheep ewes at different age stages. By automatically matching the optimal equation based on age, it reveals for the first time the dynamic changes in chest circumference as the primary indicator at 1 year old, body height as the primary indicator at 2-3 years old, and body length as the primary indicator at 4 years old, filling the technological gap of lacking age-specific dynamic models for Dolan sheep ewes. This invention predicts weight through optimal regression equations, avoiding the cumbersome process and animal stress of traditional weighing. It is simple and quick to operate, provides highly accurate weight data, and facilitates breeding and selection. Based on a large sample of 680 Dolan sheep ewes, the regression equations established in this invention have good representativeness and reliability, and are suitable for rapid assessment of group weight in grazing scenarios or large-scale indoor feeding conditions. Detailed Implementation

[0011] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0012] It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the invention. Furthermore, with respect to numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Every smaller range between any stated value or intermediate value within a stated range, and any other stated value or intermediate value within said range, is also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0013] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.

[0014] Various modifications and variations can be made to the specific embodiments described in this specification without departing from the scope or spirit of the invention, as will be apparent to those skilled in the art. Other embodiments derived from this specification will also be obvious to those skilled in the art. This application specification and embodiments are merely exemplary.

[0015] The terms “include,” “including,” “have,” “contain,” etc., used in this article are all open-ended terms, meaning that they include but are not limited to.

[0016] Unless otherwise specified, "room temperature" and "normal temperature" in this invention refer to 25±2℃.

[0017] Unless otherwise specified, all raw materials or instruments used in the following embodiments of the present invention are commercially available.

[0018] 1. Materials and Methods 1.1 Experimental Animals The experimental animals were selected from 170 ewes aged 1 to 4 years and 680 ewes from the Wuzheng National Dorgon Sheep Breeding Farm in Maigati County, Kashgar Region, Xinjiang. They were raised under uniform indoor feeding conditions.

[0019] 1.2 Measurement Indicators and Methods 170 animals aged 1 to 4 years were randomly selected, and their weight (Y) and body size (X1-X4) were measured. Weight was measured using an electronic scale with an accuracy of 0.01 kg. Body size measurements included height (X1), body length (X2), chest depth (X3), and chest circumference (X4).

[0020] The specific measurements are as follows: Body height (X1): Distance from the top of the scapula to the tip of the hoof, in cm; Body oblique length (X2): The distance from the anterior edge of the shoulder to the posterior edge of the ischial tuberosity at the buttock, in cm; Chest depth (X3): The vertical distance from the highest point of the back to the lowest point of the chest, measured along the posterior border of the scapula, in cm; Chest circumference (X4): The circumference measured around the chest along the posterior border of the scapula, in cm; 1.3 Data Statistics and Analysis Data were compiled using Excel software, and SPSS 27.0 software was used for analysis of variance, correlation analysis and stepwise regression analysis to establish the optimal regression equation between weight and body size indicators. The results are expressed as "mean ± standard deviation".

[0021] 1.4 Phenotypic Statistics of Weight and Body Size Indicators The phenotypic statistics of weight and body size indicators are shown in Table 1.

[0022] Table 1. Weight and body size indicators of Dolane ewes aged 1 to 4 years Note: Different capital letters in the same line indicate extremely significant differences. P <0.01), the same uppercase letter indicates that the difference is not significant ( P >0.01).

[0023] As shown in Table 1, the body weights of Dolane ewes aged 1 to 4 years were 55.04±5.91 kg, 55.88±7.32 kg, 61.27±8.29 kg, and 64.81±8.25 kg, respectively, and all body size indicators increased with age.

[0024] 1.5 Phenotypic Correlation Analysis of Weight and Body Size Indicators The phenotypic correlation analysis between weight and body size indicators is shown in Table 2.

[0025] Table 2 Correlation analysis of body weight and body size indicators in Dolane ewes of different ages ( r value) Note: ** indicates a highly significant correlation. P <0.01), * indicates a significant correlation ( P <0.05).

[0026] Table 2 shows that the main body size indicators affecting the weight of Dolane ewes changed significantly at different age stages. At 1 year old, the correlation coefficient between chest circumference and body weight was the highest (r=0.327, P<0.01). At 2 years old, the correlation coefficient between height and body weight was the highest (r=0.325, P<0.01). P<0.01). At age 3, height was still most closely related to weight (r=0.446, P <0.01). At age 4, the correlation coefficient between body length and body weight was the highest (r=0.454). P <0.01).

[0027] 1.6 Stepwise regression analysis of body weight and body size indicators and establishment of the optimal regression equation Stepwise regression analysis was used, with body weight as the dependent variable and height, body length, chest depth, and chest circumference as independent variables, to perform regression analysis on each age group.

[0028] The stepwise regression analysis of weight and various body size indicators is shown in Table 3.

[0029] Table 3 Stepwise regression analysis of body weight and body size parameters of Dolane ewes of different ages. Note: P <0.05 indicates a significant effect. P A value greater than 0.05 indicates that the effect is not significant.

[0030] The F-values ​​of the variance analysis for all the above regression equations reached a significant or highly significant level. P <0.05 or P <0.01), indicating that the established regression equation can be used for preliminary assessment of weight at different ages.

[0031] 1.7 Back-substitution test results of regression equations for different age groups in Dolan sheep ewes. Table 4 shows the analysis of the back-substitution test results of the regression equations for different age groups of Dolan sheep ewes. Table 4. Back-substitution test results of regression equations for Dolane ewes of different ages. Table 4 shows that the standard deviation (SD) of the predicted residuals (measured value - predicted value) for each age group is ±5.46 kg for the 1-year-old group, ±6.79 kg for the 2-year-old group, ±7.42 kg for the 3-year-old group, and ±7.10 kg for the 4-year-old group. The mean absolute error (MAE) of each equation is 4.35 kg for the 1-year-old group, 5.52 kg for the 2-year-old group, 5.96 kg for the 3-year-old group, and 5.86 kg for the 4-year-old group. The predicted values ​​are all within ±2 standard deviations of the population mean, indicating that each equation has good population estimation stability.

[0032] 1.8 Verification of Beneficial Effects The predicted weight of Dolan ewes was calculated using the optimal regression equation described above. Comparison with actual weight values ​​showed no significant difference between the predicted and actual values ​​for each age group. P>0.05), indicating that the method of the present invention can be used as an auxiliary alternative to traditional weighing, and is suitable for rapid assessment and initial screening of population weight in grazing and large-scale stall feeding scenarios, providing statistically reliable estimation data without the need for weighing.

[0033] The above description is only a preferred embodiment of the present invention. It should be noted that those skilled in the art can make several improvements and modifications without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for predicting the weight of Dolane ewes by age, characterized in that, The method includes the following steps: S1. Measure and record the body size indicators of the Dolan sheep ewes, including body height, body length, chest depth and chest circumference, and obtain the age information of the Dolan sheep ewes at the same time. S2. Determine the age group to which the Dolan sheep ewe belongs based on the age information, wherein the age group is 1 year old, 2 years old, 3 years old or 4 years old; S3. Based on the determined age group, select the corresponding equation from the pre-constructed regression equations to calculate the weight of the Dolan sheep ewes: When the Dolan sheep ewes are 1 year old, the regression equation is: =16.975+0.238X4+0.192X2; When the Dolan sheep ewes are 2 years old, the regression equation is: =2.789 + 0.371X1 + 0.275X2; When the Dolan sheep ewes are 3 years old, the regression equation is: =-4.129+0.779X1; When the Dolan sheep ewes are 4 years old, the regression equation is: =-6.153+0.554X2+0.696X3; in, X1 is the predicted weight value, X2 is the body height, X3 is the body length, X4 is the chest depth, and X5 is the chest circumference.

2. The method according to claim 1, characterized in that, The body height is the distance from the top of the scapula to the hoof tip; the body length is the distance from the front edge of the shoulder to the ischial tuberosity at the back edge of the buttock; the chest depth is the vertical distance from the highest point of the back to the lowest point of the chest, measured along the posterior edge of the scapula; and the chest circumference is the circumference measured around the chest along the posterior edge of the scapula.

3. The method according to claim 1, characterized in that, The measurements of body height, body length, chest depth, and chest circumference are in centimeters, and the weight is in kilograms.

4. The method according to claim 1, characterized in that, The Dolan sheep mentioned are Dolan ewes aged 1 to 4 years.

5. The method according to claim 1, characterized in that, The body size index is measured manually or using a 3D intelligent body size measurement system.

Images