How to Manage Pregnant Sows in Summer?

The quality of sows directly impacts the production efficiency of a pig farm. Therefore, it is essential to strengthen sow feeding management and ensure sow health to enhance farm productivity. The following ten points require special attention for efficient sow management:

1. Periods When Sows are Most Vulnerable to High Energy Intake
1. Days 3 and 8-25 post-breeding: High energy intake can lead to fertilized egg death, implantation failure, increased rates of non-pregnancy, and reduced litter size.
2. Mid-pregnancy (Days 70-90): High energy intake can impair mammary gland development in pregnant sows, leading to decreased postpartum lactation performance.

2. Sow Feeding Program
1.  Breeding Day: Immediately reduce feed intake to 1.6-1.8 kg/day and switch to gestation sow feed (14% crude protein). Nutrients are prioritized for the developing embryos, whose needs are minimal. Gestation nutrition levels generally do not affect litter size.
2.  Days 40-60 Post-Breeding: Feed 2.0 kg/day of gestation sow feed.
3.  Days 60-90 Post-Breeding: Feed 2.0-2.5 kg/day of gestation sow feed. Days 35-90 are crucial for growth, body reserve replenishment, and body condition recovery. Adjust feed (reduce or increase) for over-conditioned or thin sows to achieve an optimal state (backfat thickness of 18-19 mm) at farrowing for all parities.
4.  Day 90 Post-Breeding to Farrowing: Feed 2.5-3.0 kg/day of lactation sow feed (16% crude protein).
5.  Lactation: Feed intake = 3 kg + (330 g x number of piglets). Implement multiple small meals per day (e.g., 4-6 meals) or ad libitum feeding. Feed more in the morning and evening during summer, less at midday. Excessive weight loss during lactation affects post-weaning estrus and subsequent litter size.

3. Maintaining Optimal Body Condition in Pregnant Sows
1.  Over-Conditioned (Too Fat): Abdominal fat compresses the uterus, affecting fetal development, resulting in weak piglets. Postpartum issues include poor appetite, constipation, insufficient milk, excessive weight loss during lactation, and increased risk of crushing piglets due to reduced mobility.
2.  Under-Conditioned (Too Thin): Inadequate nutrient intake impairs fetal development, leading to weak piglets. Insufficient body reserves lead to poor milk production postpartum, affecting piglet growth. Severe weight loss also disrupts subsequent estrus and breeding.

4. Key Points in Sow Feeding
1.  Impact of Feed Mycotoxins: Approximately 25% of global grains are affected annually by mycotoxins, contributing to reduced herd immunity.
2.  Sow Sensitivity: Sows are highly sensitive. Feed contaminated with F-2 toxin (Zearalenone) can cause vulva swelling, mammary tissue enlargement, increased embryonic death, returns to estrus, abortions, anestrus, uterine prolapse, and rectal prolapse.

5. Periods When Sows are Most Vulnerable to Heat
1.  First 3 Weeks Post-Breeding: Heat stress increases fertilized egg death and implantation failure, raising return-to-estrus rates.
2.  Last 3 Weeks Pre-Farrowing: Rapid fetal growth combined with heat stress reduces uterine blood flow, weakening or killing piglets due to insufficient oxygen/nutrients.

6. Managing Pregnant Sows
1. Move sows to individual stalls and reduce feed intake immediately after breeding.
2. Implement effective cooling measures during summer for sows in the first 3 weeks post-breeding and the last 3 weeks pre-farrowing to reduce early abortions and prevent premature or weak farrowings.

7. Summer Cooling Strategies
*  Farrowing House:
* Drip cooling on sow's head/neck (requires airflow).
* Spray cooling (avoid excessive humidity).
* Air movement (avoid direct drafts on piglets).
* Negative pressure ventilation or cooling pads (ensure piglet warmth).
*  Breeding/Gestation House:
* Water flushing/sprinkling (requires airflow).
* Air movement (fans).
* Spray cooling.
*  Note: Water-based cooling (dripping, spraying, flushing) is ineffective when humidity >80% without adequate airflow.

8. Water Management
1. Ensure proper water pressure and flow rate: ~2000 ml/min when pressing the drinker.
2. Daily water requirement: 15-20 liters (winter), 30+ liters (summer).
3.  Low Pressure (any season): Reduces water/feed intake, decreases milk yield, increases sow weight loss (7-9 kg more).
4.  High Pressure (any season): Irritates throat, reduces drinking/feed intake, decreases milk yield, increases pen humidity (promotes piglet scours).
5.  Drinker Height: Correct height is crucial. Too high hinders access; too low prevents drinking and wastes water.
6.  Water Temperature: Extreme temperatures affect intake. Bury water lines to prevent summer heating. In winter (<7°C), use warm water for wet feed to boost intake.

9. Farrowing Management
1. Farrowing typically takes 2.5-3 hours. Investigate and assist/provide oxytocin if piglet intervals are prolonged. Treat retained placenta promptly.
2. Normal gestation: 112-116 days. Induce sows exceeding 118 days to prevent fetal death/decomposition causing severe metritis.
3.  Intravenous Support During Farrowing (Start at piglet 3-4):
*  Bag 1: 1500-2000 ml 5% Glucose-Saline + Houttuynia cordata inj. (15-20ml) + Vit C (20ml) + Vit B Complex (20ml) + Antibiotic (e.g., Florfenicol, Cefalosporin, Tylosin).
*  Final Bag: Add Oxytocin (20 IU for multiparous, 10 IU for primiparous). Slow drip rate. Administer final glucose bag near end of farrowing.
4.  Postpartum Care: Monitor daily for signs of Postpartum Dysgalactia Syndrome (PPDS) - check mental state, appetite, temperature, posture, vulvar discharge, udder. Treat abnormalities immediately.

10. Constipation in Sows
Constipation reduces feed intake and milk yield, increasing risk of PPDS.
Prevention/Treatment:
1. Oral administration: Glauber's salt (Sodium sulfate, 10-30g/sow daily), or 0.5% Potassium chloride or 1% Magnesium sulfate (1 tbsp on feed), or 50g artificial salt/sow daily.
2. Ensure adequate water availability (check drinkers).
3. Provide green forage.
4. Feed wet/mash feed.
5. Add "Chang Wei Hao" (fermented pure milk product) to feed: Effectively prevents constipation, diarrhea, indigestion; provides balanced amino acids and electrolytes; helps combat heat stress.