How to Improve Sow Conception Rate? A Detailed Explanation of Practical Technical Measures
Sow conception rate is the percentage of sows that are mated and become pregnant within a given period relative to the number of sows in estrus during that same period. The level of conception rate directly affects the reproductive capacity of sows, so improving sow conception rate is an effective means of enhancing sow reproductive capacity. How can sow reproductive capacity be improved?
????1. Strengthen Management
1.1 First, sows that are healthy, have normal estrus, and conceive easily should be selected and retained for breeding; second, monitoring, immunization, and treatment of various diseases affecting conception should be carried out for multiparous and replacement sows, and culling may be done when necessary; third, during farrowing of pregnant sows, the hygiene of the farrowing house should meet standards and the delivery personnel should be skilled in delivery techniques to prevent the occurrence of endometritis.
1.2 Because factors such as mycotoxins, hot weather, being overweight or underweight, and insufficient vitamin A, E, and D in the feed can all reduce sow conception rate, sow feed should be nutritionally rich, of good quality, clean, and fresh. At the same time, sows should be given appropriate exercise and restricted feeding to ensure they maintain an upper-medium body condition.
2. Semen Selection
To improve sow conception rate, semen should be collected from breeding boars that are healthy, have strong libido, produce a large ejaculation volume, and have high sperm activity. After collection, the semen should be scientifically diluted, preserved, and strictly quality-checked. Semen found to have low sperm motility, abnormalities, or thin consistency should be discarded.
????3. Timing of Mating
3.1 Estrus Identification
A sow in estrus is restless and agitated, has reduced appetite or refuses to eat, roots or jumps at the pen, makes unusual vocalizations, actively accepts mounting by a boar or mounts other sows, has a moist, swollen, congested vulva that is light red or purplish red, urinates frequently, and when pressure is applied to her lower back, she arches her back, tucks in her waist, raises her tail, and stands still; when her hindquarters are pushed forward, she shows strong counter-pressure; and when her vulva is stimulated with an instrument, she stands still.
3.2 Mating Time
For gilts being bred for the first time, they should not only have reached sexual maturity but also physical maturity. Estrus gilts that meet the requirements for first mating should receive their first mating on the morning of the 2nd day of estrus, then be mated once approximately every 10 h thereafter, for 2 to 3 consecutive matings, all completed within 2 d. For multiparous sows, if estrus begins in the morning, the first mating is done that afternoon, and the second and third matings are done on the morning and afternoon of the 2nd day respectively; if estrus begins in the afternoon, the first mating is done on the morning of the 2nd day, and the second and third matings are done on the morning and afternoon of the 3rd day respectively, with all matings completed within 2 d.
In summer, mating should be scheduled in the morning when ambient temperature is lower or after 6 p.m. Sows should be mated on an empty stomach (2 h after feeding or 1 h before feeding). Multiparous sows that come into estrus 7 d after weaning or replacement gilts that come into estrus relatively late should be mated as soon as they show estrus.
????4. Mating Methods
4.1 The mating methods for pigs include natural mating, manual assisted mating, and artificial insemination. Natural mating is when boars and sows are kept together and mate freely when the sow is in estrus; manual assisted mating is when boars and sows are kept separately and are brought together only at mating time in a fixed location, with manual assistance required during mating; artificial insemination is a breeding method in which semen is collected from a breeding boar using semen collection equipment, and after examination and processing, is inserted into the uterus of a sow to be bred using insemination equipment to impregnate her.
4.2 Compared with natural mating and manual assisted mating, artificial insemination not only has the advantages of more effectively utilizing the breed resources of excellent breeding boars, accelerating the breeding of superior breeds, reducing the spread of related diseases, significantly increasing the ratio of sows to boars, and lowering the cost of raising breeding boars, but more importantly, it can effectively improve conception rate. Therefore, artificial insemination should be advocated.
4.3 During artificial insemination, the technician grasps the sow's vulva with the left hand and inserts the insemination device about 40 cm into the vagina with the right hand. When resistance is felt, the semen is slowly injected. After insemination is complete, the semen bottle is lowered for about 5 s. If semen flows back, the backflow semen should be re-infused. If there is no backflow, the outer end of the insemination tube is folded and covered with the semen storage bottle, left still for 5 to 10 min, and then slowly withdrawn.
????5. Pregnancy Diagnosis
Pregnancy diagnosis is a means of determining whether mated sows are pregnant during the next estrous cycle after mating through non-return-to-estrus observation, boar teasing, or around 1 month after mating by ultrasound examination or estrogen measurement. Sows found to have failed mating should be re-mated promptly or culled.
Wurijilitu