Method for selecting individuals in the core group of Jersey cows based on the Jersey cow body conformation model

Abstract

The present invention relates to the field of Jersey cow breeding, and in particular to a method for screening individuals in a core group of Jersey cows based on a Jersey cow body model. The present invention uses a scientific method and three key steps to comprehensively evaluate Jersey cows: first, according to the growth characteristics of Jersey cows, 22 main traits are selected for overall scoring, and individuals with a score of 75 or above are selected for the next step of screening; cow individuals are further screened by investigating the milk quality of mother cows with an individual score of 75 or above; finally, eligible Jersey cows are finally screened based on the most important front udder attachment, suspensory ligament, rump width, udder depth and hoof angle to obtain individuals in a core group of Jersey cows. After comparison, the Jersey cow individuals screened by the present application have the advantages of high milk yield and good milk quality compared with individuals screened by conventional methods, thereby laying a solid foundation for high-quality breeding and matching of Jersey cows.

Description

Technical field

[0001] The present invention relates to the technical field of Jersey cow breeding, and in particular to a method for screening individuals in a core group of Jersey cows based on a Jersey cow body conformation model. [Background Technology]

[0002] Linear assessment of dairy cow conformation involves objectively measuring multiple traits across various body parts of each individual cow within a herd, assessing the relative biological significance of each trait within the herd, and assigning a quantitative score to each individual cow. This is currently the most scientific method for assessing individual dairy cows. This method originated with dairy associations in the United States and Canada and was introduced in both countries in 1982. In 1986, Shou Kun, a master of the Beijing Agricultural University, and others introduced linear assessment technology to China. In 1987, based on theoretical research and practical experience, he proposed a comprehensive linear scoring method that converts linear scores into functional scores, calculates body part scores, and calculates overall scores. Effective January 1, 2002, the China Dairy Association implemented the Canadian 9-point scale for assessment. The basic principle is to assign a score based on the assessor's measurement and observation of the trait, determining its position within the two extremes of its biological state. Generally, the linear score is divided into three segments: 1-3, 4-6, and 7-9. Observe which segment the trait belongs to within the three segments, then see which grade it belongs to, and then determine its linear score. The functional score is obtained from the linear score of the trait, and the functional score of the trait is weighted to obtain the part score. Finally, the part score is weighted to obtain the overall score of the cow.

[0003] At the end of 2004, the Guangxi Animal Husbandry Research Institute imported 100 Jersey heifers from New Zealand for breeding. Over a decade of adaptive observation and research has shown that Jerseys are easy to raise, highly resistant to disease, tolerate roughage, and produce consistent milk. Jerseys are docile, compact, high in milk fat, rich in protein, high in non-fat milk solids, and offer a rich, flavorful milk. Compared to Holsteins, they are also known for their high milk fat content. Jersey cattle are relatively small in weight, have thin subcutaneous fat, low basal metabolism, and high feed utilization rate. They are very adaptable to the tropical and subtropical high temperature and high humidity climate of Guangxi, and are an excellent dairy cattle breed suitable for breeding in Guangxi. Over the years, the applicant has carried out a lot of work in the breeding, adaptability, performance measurement, breeding technology, hybrid utilization, and promotion and application of Jersey cattle, accumulated relatively rich breeding experience, basically mastered the breed characteristics and production performance of Jersey cattle, and formed effective breeding techniques and methods; although there are linear evaluation standards for Holstein cattle in the industry, due to different cattle breeds, there are certain differences in the adaptation of the standards. Using the linear evaluation standards of Holstein cattle to evaluate Jersey cattle cannot screen out excellent individuals, let alone apply them to seed selection and breeding. Therefore, it is necessary to conduct a linear evaluation study on the body shape of the introduced Jersey cattle and their offspring, formulate a linear evaluation standard for the body shape of this breed of dairy cows, and use the linear evaluation standard to select excellent individuals as production cows, improve the quality of the Jersey cattle population, and improve economic benefits. [Summary of the invention]

[0004] In view of the above, it is necessary to provide a method for screening individuals in a core group of Jersey cows, which can simply and effectively screen out a core group of Jersey cows with high milk value, and the screened cows have the characteristics of high milk production and good milk quality.

[0005] In order to achieve the above object, the technical solution adopted by the present invention is:

[0006] A method for screening individuals in a core group of Jersey cows, comprising:

[0007] ① Evaluate the overall performance of Jersey cows between 60 and 150 days after giving birth, and select cows with an overall score greater than or equal to 75 as candidate cows A;

[0008] ② Monitor and calculate the milk production traits of the mother cow of candidate cow A in step ①. The milk production traits of the mother cow of the candidate individual are required to meet the following conditions: 305-day 4% standard milk yield ≥ 4800 kg, 305-day 4% standard average daily milk yield ≥ 15 kg, milk total solids rate ≥ 13%, milk protein rate ≥ 3.5%, milk fat rate ≥ 4.5% and lactose rate ≥ 4.3%, and obtain candidate cow B;

[0009] ③ The five main traits of candidate cows B were further scored, and cows with linear scores of 7 or more for front udder attachment, udder groove depth, rump width, and udder depth, and hoof angles between 50° and 55° were selected as core group cows.

[0010] Furthermore, the linear scoring method for the anterior mammary attachment is as follows: the anterior mammary attachment refers to the angle at the junction of the front edge of the mammary and the abdominal wall. When the connection is loose, the angle is small and the score is low, and when the connection is tight and the angle is large, the score is high. 120° or more is 9 points, 110°-120° is 8 points, 100°-109° is 7 points, 90°-99° is 6 points, 80°-89° is 5 points, 70°-79° is 4 points, 60°-69° is 3 points, 45°-59° is 2 points, and less than 45° is 1 point.

[0011] The linear scoring method for breast groove depth is as follows: breast groove depth refers to the degree of laxity of the central suspensory ligament, with a groove depth of more than 7 cm being 9 points, a groove depth of 7 cm being 8 points, a groove depth of 6 cm being 7 points, a groove depth of 5 cm being 6 points, a groove depth of 4 cm being 5 points, a groove depth of 3 cm being 4 points, a groove depth of 2 cm being 3 points, a groove depth of 1 cm being 2 points, and no groove being 1 point;

[0012] The linear scoring method for the hip width is as follows: hip width refers to the width between the two ischial tuberosities, measured with a circular measuring device; a hip width of 85 cm is marked as 9 points, a hip width of 84 cm is marked as 8 points, a hip width of 83 cm is marked as 7 points, a hip width of 82 cm is marked as 6 points, a hip width of 81 cm is marked as 5 points, a hip width of 80 cm is marked as 4 points, a hip width of 79 cm is marked as 3 points, a hip width of 78 cm is marked as 2 points, and a hip width of 77 cm is marked as 1 point;

[0013] The linear scoring method for udder depth is as follows: udder depth refers to the relative position of the bottom plane of the udder to the hock, with udder depth of more than 14 cm above the hock being 9 points, 12 cm above the hock being 8 points, 10 cm above the hock being 7 points, 8 cm above the hock being 6 points, 5 cm above the hock being 5 points, 2 cm above the hock being 4 points, 1 cm below the hock being 3 points, 3 cm below the hock being 2 points, and 5 cm below the hock being 1 point;

[0014] The hoof angle refers to the angle between the inclined surface of the front edge of the hoof and the ground plane.

[0015] Furthermore, the front udder attachment, udder groove depth, rump width, udder depth and hoof angle are measured on the 60th day after the first calving of the dairy cow.

[0016] In step ① above, the overall evaluation of Shanjuan cows is based on the following traits:

[0017] Body height, chest width, body depth, angularity, rump angle, rump width, hoof angle, heel depth, loin strength, forequarter strength, bone texture, hind limbs viewed from the side, hind limbs viewed from behind, udder depth, udder texture, udder groove depth, front udder attachment, front teat position, front teat length, hind chamber height, rear udder width, and rear teat position;

[0018] The scoring criteria for each trait are as follows:

[0019] Height refers to the vertical distance from the highest point of the withers to the ground, measured with a measuring stick; a height of 125 cm is marked as 9 points, a height of 123 cm is marked as 8 points, a height of 121 cm is marked as 7 points, a height of 120 cm is marked as 6 points, a height of 119 cm is marked as 5 points, a height of 118 cm is marked as 4 points, a height of 116 cm is marked as 3 points, a height of 114 cm is marked as 2 points, and a height of 111 cm is marked as 1 point;

[0020] Hip width refers to the width between the two ischial tuberosities, measured with a circular measuring device; a hip width of 32 cm is marked as 9 points. Hip width refers to the width between the two ischial tuberosities, measured with a circular measuring device; a hip width of 85 cm is marked as 9 points, a hip width of 84 cm is marked as 8 points, a hip width of 83 cm is marked as 7 points, a hip width of 82 cm is marked as 6 points, a hip width of 81 cm is marked as 5 points, a hip width of 80 cm is marked as 4 points, a hip width of 79 cm is marked as 3 points, a hip width of 78 cm is marked as 2 points, and a hip width of 77 cm is marked as 1 point.

[0021] The hoof angle refers to the angle between the inclined surface of the front edge of the hoof and the ground plane. A hoof angle of 75 degrees is marked as 9 points, a hoof angle of 70 degrees is marked as 8 points, a hoof angle of 60 degrees is marked as 7 points, a hoof angle of 55 degrees is marked as 6 points, a hoof angle of 50 degrees is marked as 5 points, a hoof angle of 45 degrees is marked as 4 points, a hoof angle of 40 degrees is marked as 3 points, a hoof angle of 35 degrees is marked as 2 points, and a hoof angle of 25 degrees is marked as 1 point.

[0022] Chest width refers to the width of the chest base between the inner sides of the two forelimbs. It is measured with a circular measuring device. A chest width of 55 cm is marked as 9 points. After that, the score decreases by 1 point for every 4 cm decrease in chest width. The lowest score is 1 point.

[0023] Body depth refers to the depth of the lower edge of the abdomen at the last rib, measured with a measuring stick; a body depth of 80 cm is marked as 9 points, and the score decreases by 1 point for every 2 cm decrease in body depth, with the lowest score being 1 point;

[0024] Hindlimb lateral view is the posture of the hindlimb viewed from the side. It is scored linearly based on the angle of flight at the elbow joint. The mark of hindlimb lateral view of 125 degrees is 9 points. The score decreases by 1 point for every 5 degrees increase in hindlimb lateral view, with the lowest score being 1 point.

[0025] The anterior nipple length refers to the length of the anterior nipple. A 9-cm anterior nipple length is marked as 9 points. After that, the score decreases by 1 point for every 1-cm decrease in the anterior nipple length, with the lowest score being 1 point.

[0026] The heel depth refers to the relative height between the upper edge of the heel and the ground. A heel depth of 3.5 cm is scored as 9 points. For every 0.25 cm decrease in heel depth, the score decreases by 1 point, with the lowest score being 1 point.

[0027] The front section strength is a comprehensive score based on the width, depth, nose width and forequarter bone structure of the cow. Strong and sturdy individuals score high, while thin and narrow individuals score low. The highest score is 9 points and the lowest score is 1 point.

[0028] Lumbar strength refers to the strength of the connection between the sacral vertebrae and the first lumbar vertebrae and the development of the short ribs in the waist. The lumbar vertebrae with a high protrusion score have a low concave score. The lumbar vertebrae with a high protrusion score is 9 points, the lumbar vertebrae with a straightness score is 5 points, and the lumbar vertebrae with a concave score is 1 point.

[0029] Croup angle refers to the relative height between the ischial end and the waist angle; the score of high waist and low hips is high, and the score of low waist and high hips is low, with the highest score being 9 points and the lowest score being 1 point;

[0030] Bone texture refers to the fineness and firmness of the hind limb bones; wide, flat, and fine are scored high, while thick and loose femurs are scored low. The highest score is 9 points, and the lowest score is 1 point.

[0031] Hind view refers to the degree of parallelism and verticality of the two hocks of the hind limbs. If the hocks are parallel and vertical to the ground, the score is high. If the two hocks are wide apart or inward, the score is low. The highest score is 9 points and the lowest score is 1 point.

[0032] Breast depth refers to the relative position of the bottom plane of the breast and the hock. Breast depth refers to the relative position of the bottom plane of the breast and the hock. 14cm above the hock is 9 points, 12cm above the hock is 8 points, 10cm above the hock is 7 points, 8cm above the hock is 6 points, 5cm above the hock is 5 points, 2cm above the hock is 4 points, 1cm below the hock is 3 points, 3cm below the hock is 2 points, and 5cm below the hock is 1 point.

[0033] Breast texture refers to the skin texture of the breast. The larger the difference in volume before and after milking, the higher the score is for glandular breasts, and vice versa. Glandular breasts are scored 9 points, semi-glandular and semi-connective breasts are scored 5 points, and connective breasts are scored 1 point.

[0034] The depth of breast cleavage refers to the degree of laxity of the central suspensory ligament. A deep breast cleavage scores higher and a shallow breast cleavage scores lower. The depth of breast cleavage refers to the degree of laxity of the central suspensory ligament. A sulcus depth of more than 7 cm is 9 points, a sulcus depth of 7 cm is 8 points, a sulcus depth of 6 cm is 7 points, a sulcus depth of 5 cm is 6 points, a sulcus depth of 4 cm is 5 points, a sulcus depth of 3 cm is 4 points, a sulcus depth of 2 cm is 3 points, a sulcus depth of 1 cm is 2 points, and no sulcus is 1 point.

[0035] The anterior breast attachment refers to the angle at which the front edge of the breast connects to the abdominal wall. When the attachment is loose, the angle is small and the score is low. When the attachment is fully and tightly connected, the angle is large and the score is high. 9 points for an angle of 120° or more, 8 points for 110°-120°, 7 points for 100°-109°, 6 points for 90°-99°, 5 points for 80°-89°, 4 points for 70°-79°, 3 points for 60°-69°, 2 points for 45°-59°, and 1 point for an angle of less than 45°.

[0036] The anterior nipple position and posterior nipple position both refer to the position of the nipple in the breast area. The more concentrated the nipple distribution, the higher the score; the more dispersed the nipple distribution, the lower the score; the highest score is 9 points and the lowest score is 1 point; concentrated nipple is 9 points, central nipple distribution is 5 points, and dispersed nipple is 1 point;

[0037] Hindquarter height refers to the vertical distance from the top of the milk-secreting tissue to the base of the vulva. A body shape with an extremely high top of the milk-secreting tissue is the optimal body shape for modern dairy cows. A hindquarter height of less than 20 cm is scored as 9 points, a hindquarter height of 21 cm is scored as 8 points, a hindquarter height of 23 cm is scored as 7 points, a hindquarter height of 25 cm is scored as 6 points, a hindquarter height of 27 cm is scored as 5 points, a hindquarter height of 29 cm is scored as 4 points, a high hindquarter height of 31 cm is scored as 3 points, a hindquarter height of 33 cm is scored as 2 points, and a hindquarter height of 35 cm or more is scored as 1 point.

[0038] The posterior breast width refers to the width between the left and right attachment points of the posterior chamber. A narrow posterior breast width is scored low, and a wide one is scored high. A posterior breast width greater than 20 cm is scored as 9 points, a posterior breast width of 18 cm is scored as 8 points, a posterior breast width of 15 cm is scored as 7 points, a posterior breast width of 14 cm is scored as 6 points, a posterior breast width of 13 cm is scored as 5 points, a posterior breast width of 12 cm is scored as 4 points, a posterior breast width of 11 cm is scored as 3 points, a posterior breast width of 8 cm is scored as 2 points, and a posterior breast width less than 6 cm is scored as 1 point.

[0039] Angularity is a comprehensive assessment of the fineness and compactness of the cattle's head, neck, withers, thighs, limb joints, skin, and bones; clear outlines are scored high, and unclear outlines are scored low; the highest score is 9 points, and the lowest is 1 point; clear outlines are scored 9 points, very clear outlines are scored 6 points, and unclear outlines are scored 1 point.

[0040] Furthermore, the linear scores of the above traits were converted into a percentage system using the following table to obtain the scores of each part:

[0041]

[0042]

[0043] After the linear score is converted to a percentage system, the overall score of the dairy cow is calculated according to the following calculation model:

[0044] Overall score = ∑(score of each part × weighted coefficient of part × weighted coefficient of trait);

[0045] In the formula, body height, front section strength, chest width, waist strength and body depth belong to body volume, and the weighting coefficient of each part is 15%, and the weighting coefficient of each trait is 20%.

[0046] Buttock angle and buttock width belong to the buttocks, and their weighted coefficients are both 10% and 50% respectively;

[0047] Hoof angle, heel depth, bone texture, hind limb side view and hind limb back view belong to the hoof part, and the weighted coefficient of the part is 25%; the weighted coefficients of the traits are: hoof angle 25%, heel depth 25%, bone texture 10%, hind limb side view 25% and hind limb back view 15%;

[0048] Udder depth, udder texture, posterior chamber height, udder cleavage depth, anterior udder attachment, anterior nipple position, anterior nipple length, posterior udder width, posterior nipple position and angularity are milk characteristics, and their position weighting coefficient is 50%; the trait weighting coefficients are all 10%.

[0049] Furthermore, the calculation model of the 305-day 4% standard milk volume in step ② is as follows:

[0050] 305-day 4% standard milk volume = M × (0.4 + 15F), where F is the actual fat content of the milk and M is the 305-day corrected milk volume with a fat content of F;

[0051] The calculation model of the 305-day corrected milk volume is as follows:

[0052] Corrected milk production at 305 days = total milk production × correction factor

[0053] The correction coefficients in the above 305-day corrected milk volume calculation formula are shown in the following table:

[0054]

[0055]

[0056] Furthermore, the calculation model for the 305-day 4% standard average daily milk production is as follows:

[0057] 305-day 4% standard average daily milk production = {305-day corrected milk production with fat content F × (0.4 + 15 × milk fat content F)} ÷ 305

[0058] Furthermore, the calculation model of the total solid content of milk is as follows:

[0059] Total solids content of milk = 100% total solids content in fresh milk (g) / 100% weight of fresh milk (g) × 100%

[0060] Furthermore, the milk protein rate calculation model is as follows:

[0061] Milk protein rate = 100g fresh milk protein weight (g) / 100g fresh milk weight (g) × 100%

[0062] Furthermore, the milk fat rate calculation model is as follows:

[0063] Milk fat rate = 100g fresh milk fat weight (g) / 100g fresh milk weight (g) × 100%

[0064] Furthermore, the lactose rate calculation model is as follows:

[0065] Lactose rate = lactose weight (g) of 100 g of fresh milk / weight (g) of 100 g of fresh milk × 100%.

[0066] The present invention has the following beneficial effects:

[0067] 1. This invention uses a scientific method to comprehensively evaluate Jersey cows using three key steps: first, based on the growth characteristics of Jersey cows, 22 key traits are selected for overall scoring. Individuals with a score of 75 or above are selected for further screening. Further screening is conducted by investigating the milk quality of the mother cows with a score of 75 or above. Finally, eligible Jersey cows are screened based on the most important characteristics of front udder attachment, suspensory ligament, rump width, udder depth, and hoof angle. This results in a core group of Jersey cows. Comparison shows that Jersey cows screened using this application have advantages in milk production and quality compared to those screened using conventional methods. Compared to conventional screening methods, the total milk production increased by 7.93%, the average daily milk yield per cow increased by 8.33%, the 305-day 4% standard milk increased by 19.82%, and the average daily standard milk yield per cow increased by 20.28%. The implementation of this scheme has greatly improved the quality of the Jersey cow core group, laying a solid foundation for the high-quality selection and breeding of Jersey cows. [Specific implementation method]

[0068] All features disclosed in this specification, or all steps in the disclosed methods or processes, except mutually exclusive features and / or steps, can be combined in any manner.

[0069] Any feature disclosed in this specification (including any accompanying claims and abstract), unless otherwise stated, is merely one example of a series of equivalent or similar features.

[0070] Example 1:

[0071] This embodiment mainly studies the method for screening the core group of Shanjuan dairy cows, which is as follows:

[0072] The total score requirement for the linear assessment of body shape of individual dairy cows is: the total score of the participating dairy cows must be no less than 75 points, and only then can they be selected as individuals for the core group.

[0073] (1) Steps for linear scoring of body shape:

[0074] 1. Determine 22 traits for linear conformation assessment of Jersey cattle.

[0075] 2. Develop trait measurement methods and linear scoring standards.

[0076] 3. Develop a comparison table for converting linear scores into percentage-based functional scores

[0077] 4. Measure the various traits of dairy cows according to the trait measurement method, and obtain the linear score by comparing it with the linear scoring standard.

[0078] 5. According to the linear score and functional score conversion table, convert each linear score into a functional score. The weighted sum of each trait functional score is the total individual body score.

[0079] (2) Definition of traits

[0080] Body measurements and trait data collection were performed using measuring rods, circular measuring instruments, tape measures, and protractors. The instruments and their usage complied with the requirements of GB / T 19022.

[0081] 1. Body height: The vertical distance from the highest point of the withers to the ground, measured with a measuring rod.

[0082] 2. Chest width: The width of the chest base on the inner side of the two front legs, measured with a circular measuring instrument.

[0083] 3. Body depth: The depth of the lower edge of the abdomen at the last rib, measured with a measuring rod.

[0084] 4. Angularity: Angularity reflects the dairy characteristics of the cow. It comprehensively evaluates the fineness and compactness of the cow's head, neck, withers, thighs, limb joints, skin, and bones, which is the appearance of the dairy cow.

[0085] 5. Croup angle: refers to the relative height between the ischial tuberosity and the waist angle.

[0086] 6. Croup width: refers to the width between the two ischial tuberosities, measured with a circular measuring instrument.

[0087] 7. Hoof Angle: This refers to the angle between the front edge of the hoof and the ground plane. Cows with extremely low or extremely high hoof angles do not have the optimal hoof angle. The appropriate hoof angle is 55 degrees.

[0088] 8. Heel depth: refers to the relative height between the upper edge of the heel and the ground.

[0089] 9. Lumbar Strength: This measure measures the firmness of the waist, referring to the strength of the connection between the sacral vertebrae and the first lumbar vertebra, and the development of the short ribs in the waist. A slightly raised lumbar vertebra and well-developed short ribs indicate the highest score, while a lower score indicates a lower score.

[0090] 10. Frontal Firmness: This refers to the comprehensive scoring of individual cows, including chest width, depth, nose width, and forequarter bone structure. Strong and robust cows score higher, while weak and narrow cows score lower.

[0091] 11. Bone Texture: This refers to the fineness and strength of the hind limb bones. Broad, flat, and fine bones score highest. A thick, porous femur scores lowest.

[0092] 12. Side view of hind limbs: Mainly look at the posture of the hind limbs from the side, and make a linear score based on the angle of the flying angle at the elbow joint.

[0093] 13. Hind legs: The degree of parallelism and verticality of the two hocks in rear view. The highest score is given when the hocks are parallel and vertical to the ground, while the scores are lower when the two hocks are wide apart or point inward.

[0094] 14. Udder depth: This is primarily based on the relative position of the udder base to the hock, not a linear assessment. Udder depth is not optimal for cows with either too deep or too shallow udders.

[0095] 15. Breast texture: Breasts with thin skin, elasticity to the touch, and large volume differences before and after milking are glandular breasts, which have high scores. Connective breasts have the lowest scores.

[0096] 16. Breast cleavage depth: This represents breast suspensory quality. A linear score is calculated based on the clarity of the central suspensory ligament when viewed from behind. A loose central suspensory ligament with no cleavage is the lowest score, while a firm, strong suspensory ligament with a cleavage is the highest score.

[0097] 17. Anterior Breast Attachment: This is scored linearly based on the strength of the attachment of the lateral ligaments to the abdominal wall. This is the angle at which the anterior breast connects to the abdominal wall. A loose attachment results in a smaller angle and a lower score, while a tight attachment results in a larger angle and a higher score.

[0098] 18. Anterior Nipple Position: This refers to the position of the nipples in the breast area. The more concentrated the nipples are, the higher the score; the more dispersed the nipples are, the lower the score.

[0099] 19. Front teat length: Teat length affects the ease of milking. A teat 10 cm tall is the highest score, with scores decreasing for teats shorter or longer than 10 cm.

[0100] 20. Hindquarter height: This is a factor in udder volume and is directly related to milk production and storage capacity. A linear score is calculated based on the vertical distance from the top of the milk-secreting tissue to the base of the vulva. Hindquarter height indicates a cow's potential lactation capacity. A cow with an extremely high top of the milk-secreting tissue is considered optimal for modern dairy cows.

[0101] 21. Posterior chamber width: This is scored linearly based on the width between the left and right attachment points of the posterior chamber. A narrow posterior chamber is scored low, while a wide posterior chamber is scored high.

[0102] 22. Posterior nipple position: It reflects the uniformity of nipple distribution. The more concentrated the nipple distribution, the higher the score; the more discrete the nipple distribution, the lower the score.

[0103] The linear scoring table for specific traits is shown in Table 1 below:

[0104] Table 1 Linear scoring table for traits of Jersey cows (9-point system)

[0105]

[0106]

[0107] (3) Requirements for assessment objects and methods for assessors

[0108] The assessment targets healthy postpartum Jersey cows, conducted between 60 and 150 days postpartum. Cows are assessed standing naturally on a wide, flat surface, and the assessor performs a linear assessment within visual range of the individual cows. First, the assessor walks around the cow's body to determine the symmetry of its various body parts. Next, the assessor observes the cow from the front, side, and rear. From the front, the cow's head structure, chest and haunch width, rib splay, and forelimb posture are observed. From the side, the cow's chest depth, overall body shape and volume, shoulder and rump slope, length of the neck, back, haunch, and rump, udder and limb development, and symmetry are observed. From the rear, the width of the haunch and rump, udder size and shape, and hindlimb posture are observed. The assessment is performed visually, followed by palpation, to assess the development of the skin, subcutaneous tissue, muscle, bone, hair, horns, and udder. Finally, let the cattle walk freely and observe the movements of its limbs and its gait.

[0109] (IV) Calculation of total body shape score

[0110] Record the cow's measurements and evaluations using body measurement tools or visual evaluation. Lengths are measured in centimeters (cm). Compare the linear scores for each trait in the cow to the linear scoring standard table. The linear scores range from 1 to 9. Each trait has a different impact on appearance. Based on Table 2, these scores are converted to corresponding body part scores:

[0111] Table 2: Linear score conversion of Jersey cows for each part (percentage system)

[0112]

[0113] The overall score of the cow is then calculated according to the following formula:

[0114] Overall score = ∑(score of each part × weighted coefficient of part × weighted coefficient of trait);

[0115] In the formula, body height, front section strength, chest width, waist strength and body depth belong to body volume, and the weighting coefficient of each part is 15%, and the weighting coefficient of each trait is 20%.

[0116] Buttock angle and buttock width belong to the buttocks, and their weighted coefficients are both 10% and 50% respectively;

[0117] Hoof angle, heel depth, bone texture, hind limb side view and hind limb back view belong to the hoof part, and the weighted coefficient of the part is 25%; the weighted coefficients of the traits are: hoof angle 25%, heel depth 25%, bone texture 10%, hind limb side view 25% and hind limb back view 15%;

[0118] Udder depth, udder texture, posterior chamber height, udder cleavage depth, anterior udder attachment, anterior nipple position, anterior nipple length, posterior udder width, posterior nipple position and angularity are milk characteristics, and their position weighting coefficient is 50%; the trait weighting coefficients are all 10%.

[0119] The details are shown in Table 3:

[0120] Table 3 Part weighting coefficients and trait weighting coefficients for linear evaluation of body shape of Jersey cows

[0121]

[0122] Taking a height of 119 cm as an example, calculate the trait function score for height:

[0123] The linear score of 119 cm in Table 1 is 5 points, which is converted to a percentage system in Table 2 to 90 points;

[0124] From Table 3, we know that body height belongs to body volume, the weighting coefficient of body part is 15%, and the weighting coefficient of traits is 20%.

[0125] Therefore, for a Jersey cow with a height of 119 cm, the functional score for this trait is:

[0126] 90×0.15×0.2=2.7 points;

[0127] To evaluate the overall traits of Jersey cows, each trait needs to be calculated according to the above method to obtain the corresponding functional score, and then the functional scores are added together to obtain the overall total score, that is, the overall total score = ∑(score of each part × part weighting coefficient × trait weighting coefficient).

[0128] Example 2:

[0129] Scoring was performed using the method of Example 1, and Jersey cows with an overall score greater than 75 points were selected as candidate individuals for the core group, and were marked as candidate cows A.

[0130] Monitor and calculate the milk production traits of the mother cow of candidate dairy cow A. The milk production traits of the mother cow of the candidate individual are required to meet the following conditions: 305-day 4% standard milk yield ≥4800 kg, 305-day 4% standard average daily milk yield ≥15 kg, milk total solid rate ≥13%, milk protein rate ≥3.5%, milk fat rate ≥4.5% and lactose rate ≥4.3%, and obtain candidate dairy cow B;

[0131] in,

[0132] ① The calculation model of 4% standard milk volume for 305 days is as follows:

[0133] 305-day 4% standard milk volume = M × (0.4 + 15F), where F is the actual fat content of the milk and M is the 305-day corrected milk volume with a fat content of F;

[0134] The calculation model of the 305-day corrected milk volume is as follows:

[0135] Corrected milk production at 305 days = total milk production × correction factor

[0136] The correction coefficients in the above 305-day corrected milk production calculation formula are shown in Table 4:

[0137] Table 4 Correction coefficients for dairy cows at 305 days

[0138] Actual milk production days 240 250 260 270 280 290 300 305 First child 1.182 1.148 1.116 1.086 1.055 1.031 1.011 1.0 2 to 5 births 1.165 1.133 1.103 1.077 1.052 1.031 1.011 1.0 More than 6 births 1.155 1.123 1.094 1.070 1.047 1.025 1.009 1.0 Actual milk production days 310 320 330 340 350 360 370 First child 0.987 0.965 0.947 0.924 0.911 0.895 0.881 2 to 5 births 0.988 0.970 0.952 0.936 0.925 0.911 0.904 More than 6 births 0.988 0.970 0.956 0.940 0.928 0.916 0.993

[0139] ② The calculation model for the 305-day 4% standard average daily milk production is as follows:

[0140] 305-day 4% standard average daily milk production = {305-day corrected milk production with fat content F × (0.4 + 15 × milk fat content F)} ÷ 305

[0141] ③The calculation model of total solid content of milk is as follows:

[0142] Total solids content of milk = 100% total solids content in fresh milk (g) / 100% weight of fresh milk (g) × 100%

[0143] ④The milk protein rate calculation model is as follows:

[0144] Milk protein rate = 100g fresh milk protein weight (g) / 100g fresh milk weight (g) × 100%

[0145] ⑤The milk fat rate calculation model is as follows:

[0146] Milk fat rate = 100g fresh milk fat weight (g) / 100g fresh milk weight (g) × 100%

[0147] ⑥The lactose rate calculation model is as follows:

[0148] Lactose rate = lactose weight (g) of 100 g of fresh milk / weight (g) of 100 g of fresh milk × 100%.

[0149] Example 3:

[0150] After candidate cows B were screened according to the method of Example 2, further linear scoring was performed on the candidate cows for udder attachment, udder cleavage depth, rump width, udder depth, and hoof angle. The linear scores were measured 60 days after the first parity. Cows with linear scores of 7 or higher for udder attachment, udder cleavage depth, rump width, and udder depth and hoof angles between 50° and 55° were selected as the core group.

[0151] The above method (marked as the screening method of this application) and the conventional evaluation method based on the book "Linear Assessment of Dairy Cow Body Shape" published by the China Dairy Association (marked as the conventional screening method) were used to screen the core group of Jersey cows. The results are shown in Table 5:

[0152] Table 5 Comparison table of milk production traits of Jersey cows screened by different screening methods

[0153]

[0154] As shown in Table 5, the core herd of Jersey cows screened using the screening method of this application achieved a 7.93% increase in milk production over the conventional screening method, an 8.33% increase in daily milk production per cow, a 19.82% increase in 305-day 4% standard milk production, and a 20.28% increase in daily standard milk production per cow. The implementation of this program has significantly improved the quality of the core herd of Jersey cows, laying a solid foundation for high-quality breeding and selection of Jersey cows.

[0155] In summary, after a large number of experiments, summaries and explorations, the Jersey cow core group evaluation method of this application has screened out Jersey milk with better milk yield and quality than Jersey cows screened out by conventional methods. It is an effective method for screening core groups of dairy Jersey cows.

[0156] The above-described embodiments merely illustrate several embodiments of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that a person skilled in the art would be able to make various modifications and improvements without departing from the spirit of the present invention, all of which fall within the scope of protection of the present invention. Therefore, the scope of protection of the present invention shall be determined by the appended claims.

Claims

1. A method for screening individuals in a core group of Jersey cows, characterized in that: The method is: ① Evaluate the overall performance of Jersey cows between 60 and 150 days after giving birth, and select cows with an overall score greater than or equal to 75 as candidate cows A; ② Monitor and calculate the milk production traits of the mother cow of candidate cow A in step ①. The milk production traits of the mother cow of the candidate individual are required to meet the following conditions: 305-day 4% standard milk yield ≥ 4800 kg, 305-day 4% standard average daily milk yield ≥ 15 kg, milk total solids rate ≥ 13%, milk protein rate ≥ 3.5%, milk fat rate ≥ 4.5% and lactose rate ≥ 4.3%, and obtain candidate cow B; The 305-day 4% standard milk volume calculation model is as follows: 305-day 4% standard milk volume = M × (0.4 + 15F), where F is the actual fat content of the milk and M is the 305-day corrected milk volume with a fat content of F; The 305-day corrected milk volume is as follows: ③ Further score the five main traits of candidate cow B, and select cows with linear scores of 7 or more for front udder attachment, udder groove depth, rump width, and udder depth, and hoof angles between 50° and 55° as core group cows; The linear scoring method for the anterior mammary attachment is as follows: the anterior mammary attachment refers to the angle at which the front edge of the mammary gland connects to the abdominal wall. When the connection is loose, the angle is small and the score is low. When the connection is tight and the angle is large, the score is high. 120° or more is 9 points, 110°-120° is 8 points, 100°-109° is 7 points, 90°-99° is 6 points, 80°-89° is 5 points, 70°-79° is 4 points, 60°-69° is 3 points, 4 5°-59° is 2 points, and 45° or less is 1 point. The linear scoring method for breast cleavage depth is as follows: breast cleavage depth refers to the degree of laxity of the central suspensory ligament. Atrial sulcus depth of 7 cm or more is 9 points, atrial sulcus depth of 7 cm is 8 points, atrial sulcus depth of 6 cm is 7 points, atrial sulcus depth of 5 cm is 6 points, atrial sulcus depth of 4 cm is 5 points, atrial sulcus depth of 3 cm is 4 points, atrial sulcus depth of 2 cm is 3 points, atrial sulcus depth of 1 cm is 2 points, and no atrial sulcus is 1 point. The linear scoring method for buttock width is as follows: Hip width refers to the width between the two ischial tuberosities, measured with a circular measuring device; a hip width of 85 cm is marked as 9 points, a hip width of 84 cm is marked as 8 points, a hip width of 83 cm is marked as 7 points, a hip width of 82 cm is marked as 6 points, a hip width of 81 cm is marked as 5 points, a hip width of 80 cm is marked as 4 points, a hip width of 79 cm is marked as 3 points, a hip width of 78 cm is marked as 2 points, and a hip width of 77 cm is marked as 1 point; the breast depth is 9 points. The linear scoring method for the degree of depth is as follows: udder depth refers to the relative position of the bottom plane of the udder and the hock, with a score of 9 for more than 14 cm above the hock, 8 for 12 cm above the hock, 7 for 10 cm above the hock, 6 for 8 cm above the hock, 5 for 5 cm above the hock, 4 for 2 cm above the hock, 3 for 1 cm below the hock, 2 for 3 cm below the hock, and 1 for 5 cm above or below the hock. The hoof angle refers to the angle between the inclined surface of the front edge of the hoof and the ground plane.

2. The screening method according to claim 1, wherein The measurement time of the front udder attachment, udder groove depth, rump width, udder depth and hoof angle is 60 days after the first calving of the dairy cow.

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