Do you know the Analysis of Artificial Insemination Techniques in Large-Scale Breeding Farms?

What is Artificial Insemination in Swine?

I. Advantages of Artificial Insemination

① Helps prevent infectious diseases

② Increases boar utilization rates

③ Facilitates the promotion of superior breeds and superior sires

④ Enables timely insemination of sows in estrus

⑤ Overcomes difficulties in natural mating due to excessive size differences between boars and sows

⑥ Improves breeding performance

⑦ Reduces production costs

II. Training Semen Collection Boars

① Train sexually active boars first; observe and learn from the next one through a partition.

② Clean the boar's abdomen and prepuce area, express accumulated urine from the prepuce, and disinfect the abdomen and prepuce with a 0.1% potassium permanganate solution. Massage the boar's prepuce area.

③ Induce mounting behavior: Apply urine from a estrous sow to the artificial mount while mimicking sow vocalizations. Alternatively, use urine or saliva from other boars on the mount to trigger mounting.

④ If the above methods fail, bring in an estrous sow. Allow the boar to mount her several times, then remove the sow when the boar is highly aroused.

⑤ Once the boar mounts the dummy, proceed with semen collection.

⑥ For successfully trained boars, collect semen every other day for one week to reinforce memory and establish conditioned reflexes. For difficult-to-train boars, conduct multiple brief training sessions (4-5 times weekly, max 15-20 minutes per session). Immediately cease training if the boar shows signs of frustration, boredom, or loss of interest. Backup boars typically begin semen collection training at 8 months of age.

III. Semen Collection

① Preparing the collection cup: Line an insulated cup with a disposable plastic bag and cover the rim with filter paper, submerging it approximately 2 cm. Secure with a rubber band. Store the collection cup in a 37°C incubator. To ensure accurate internal temperature, store the collection cup and lid separately within the incubator.

② Drive the boar to the collection pen. Before collection, trim hair from the prepuce to prevent interference and semen contamination.

③ Squeeze out accumulated urine from the prepuce. Clean the abdomen and prepuce area with a 0.1% potassium permanganate solution, then rinse thoroughly with water and pat dry. Massage the preputial area. Once the boar mounts the artificial platform, wear a latex glove and firmly grasp the protruding glans. As the boar thrusts forward, straighten the S-shaped curvature of the penis. Securely hold the first and second folds of the penile spiral. Allow the penis to extend naturally during thrusting without excessive pulling. Once fully extended, the penis will cease thrusting, reaching a rigid locked state and initiating ejaculation. Maintain a firm grip throughout ejaculation; releasing pressure will interrupt the process. Avoid touching the shaft of the penis during collection, as this will cause it to retract rapidly.

④ Do not collect the initial small volume of semen (approximately 5 milliliters). Begin collection when thick semen appears and continue until the boar finishes ejaculating (penis softens), then release. Take care to prevent fluid from the prepuce region from entering the collection cup during the process.

⑤ Complete the boar semen collection record form immediately after collection.

⑥ Immediately transport the collection cup to the laboratory for semen quality testing upon completion. Thoroughly clean the collection pen before leaving work.

⑦ Collection Frequency:

- For replacement boars from training completion to 12 months of age: 7-day intervals. Typically, semen density should not fall below 100 million/ml. For adult boars, the standard collection frequency is 3 times every 2 weeks. During summer, heat stress may reduce semen yield, so carefully adjust collection intervals accordingly.

⑧ Interval between collection and feeding: Maintain at least a 1-hour gap after collection. Begin feeding 45-60 minutes before the end of the work shift.

IV. Semen Quality Inspection

The entire inspection process must be swift and accurate, typically completed within 5-10 minutes to prevent prolonged exposure that could impair semen motility. Key semen quality indicators include: ejaculate volume, color, odor, sperm concentration, sperm motility, and sperm deformity rate. Immediately after inspection, complete the Boar Semen Quality Inspection Record Form. Maintain comprehensive semen records for each boar.

1. Volume

Young boars typically produce 150-200 milliliters, while mature boars yield 200-600 milliliters. Volume is calculated by weighing the sample, with 1 gram equaling 1 milliliter.

2. Color

Normal semen appears milky white or grayish white. Abnormal semen color indicates impurity or reproductive tract pathology in the boar. Discard any semen with abnormal coloration. Simultaneously examine the boar and administer appropriate treatment.

3. Odor: Normal boar semen possesses a characteristic faint fishy odor without putrid or foul smells. Semen with unusual odors typically indicates contamination with urine or foreign substances.

4. Density

This refers to the number of sperm per milliliter of semen and is crucial for determining the dilution ratio. Normal boar sperm concentration ranges from 200 million to 300 million/mL. To enhance sperm motility after dilution, adjust the density through collection intervals, maintaining it between 250 million and 300 million/mL.

5. Sperm Motility Sperm motility must be assessed after each collection and before semen use. Pre-warm the sample on a 37°C (98.6°F) incubator plate prior to testing. Motility is typically graded on a 10-point scale: - 0.9 motility: 90% sperm exhibit straight-line movement in one microscopic field - 0.8 motility: 80% exhibit straight-line movement and so on. Grading precision to 0.05 is sufficient. Fresh semen with motility above 0.7 is considered normal; semen with motility below 0.65 is unusable.

6. Abnormal Sperm Rate

Abnormal sperm include giant, short, tail-broken, head-broken, acrosome-depleted, large-headed, double-headed, double-tailed, and bent-tailed sperm. These sperm generally fail to move in a straight line and have poor fertilization capacity, though they do not affect sperm density.

7. Grade Evaluation After completing all parameter checks, promptly evaluate the grade of boar semen. Discard semen with motility below 0.65, deformity rate exceeding 18%, or volume less than 100 milliliters.

V. Semen Dilution

Prepare 500g/bag of long-acting dilution powder mixed with 500ml distilled water. Preheat the water bath to 37-39°C for one hour.

All semen processing must occur in a temperature-controlled environment. Both quality-checked semen and dilution solution must be preheated at 37°C. During dilution, direct sunlight exposure to semen is strictly prohibited. The dilution solution should be prepared one hour before semen collection. Dilution must be performed promptly after collection. Semen that has not undergone quality inspection or has a sperm motility below 0.65 should not be used for dilution.

① Determining the Dilution Dose: The standard artificial insemination dose is typically 4 billion sperm per dose, with a volume of 80 milliliters. For example, if a boar's raw semen has a density of 200 million/mL and a collection volume of 150 mL, with a post-dilution requirement of 4 billion/dose and 80 mL volume, the semen can be diluted into 150 × 2/40 = 7.5 doses. The required dilution solution volume is 80 × 7.5 - 150 = 450 mL.

② Measure the temperature of both semen and diluent, adjusting the diluent to match the semen temperature (within 1°C difference, with diluent slightly warmer).

③ Transfer semen to a 2000-mL beaker. Slowly add diluent along the beaker wall while gently mixing.

④ For high-ratio dilution, first perform a 1:1 low-ratio dilution. After 1 minute, slowly distribute the remaining diluent throughout the mixture. Since sperm require an adaptation period, never pour diluent directly into semen.

⑤ Check motility at each dilution step. Allow the diluted sample to rest briefly before testing motility. Investigate and correct any decline in motility.

⑥ Semen Pooling: Semen from two or more boars may be pooled after 1:1 dilution or full dilution. Before pooling, mix a small portion from each sample to check for motility decline; if reduced, do not proceed. Pour warmer semen into cooler semen. Check motility at each step. The principle for mixing semen is: Grade 1 semen mixes with Grade 1 semen; Grade 2 mixes with Grade 2; Grade 3 should be avoided whenever possible. Do not mix semen across grades.

⑦ Thoroughly clean all equipment; the success of semen dilution is highly dependent on the cleanliness of all instruments. All used beakers, glass rods, and thermometers must be promptly rinsed with distilled water and subjected to high-temperature sterilization to ensure the diluted semen can be stored and utilized within the appropriate timeframe.

⑧ Semen Portioning: First, verify that all contact materials are non-toxic to sperm. Only materials confirmed as harmless may be used in production. After diluting semen, first check sperm motility. If motility shows no significant decline (within 0.05), proceed with portioning. Portion into 60-80 ml doses per animal. When using bottles, minimize air exposure by expelling air from the bottle (squeeze the insemination bottle flat before sealing the cap) to reduce stress on sperm from transportation vibrations. After portioning, seal the semen containers, affix labels, and mark the boar breed, semen grade, collection date, and semen batch number.

⑨ Semen Vitality Check: After semen production, retain 1-2 semen samples for continuous 24-hour vitality monitoring and record-keeping, with periodic summaries.

⑩ Record-keeping: Maintain detailed semen dilution records.