The breeding season is a critical period that determines reproductive performance in sheep enterprises. Nutritional strategies applied during this period, especially flushing, can significantly increase ovulation rate and therefore the twinning rate. With correct nutritional management, flock productivity can be maximized.
1. Importance of the Breeding Season
1.1 Factors Affecting Reproductive Performance
- Body condition of the ewe
- Level of nutrition
- Breed and genetics
- Age
- Season and photoperiod
- Ram quality and ram-to-ewe ratio
- Health status
1.2 Targets
- High estrus rate
- High ovulation rate
- High conception rate
- Low embryo loss
- Optimal twinning rate
2. What Is Flushing?
2.1 Definition
Flushing is an intensive feeding practice that starts 2-3 weeks before ram introduction and continues through the breeding period.
2.2 Effects of Flushing
- Increases ovulation rate by 10-20%
- Increases the twinning rate
- Improves estrus synchronization
- Improves conception rate
2.3 Mechanism of Flushing
- Higher energy intake -> blood glucose rises
- Insulin and IGF-1 increase
- FSH and LH secretion is stimulated
- Follicular development accelerates
- Number of ovulations increases
3. Practical Application of Flushing
3.1 Timing
| Period | Duration | Application |
|---|---|---|
| Before flushing | 3-4 weeks before breeding | Body condition score (BCS) evaluation |
| Start of flushing | 2-3 weeks before breeding | Supplementary feeding begins |
| Breeding period | 3-5 weeks | Flushing continues |
| After breeding | 2-3 weeks | Gradual reduction |
3.2 Flushing Ration
- In addition to the current ration, provide 250-500 g concentrate per ewe per day
- Or provide 2-3 extra hours of grazing per day on high-quality pasture
- Energy increase: 30-50%
3.3 Concentrate Feed Composition
| Ingredient | Inclusion (%) |
|---|---|
| Barley | 50-60 |
| Maize | 20-30 |
| Bran | 10-15 |
| Mineral-vitamin mix | 2-3 |
3.4 Situations Where Flushing Is Most Effective
- ✅ Ewes in moderate condition (BCS 2.5-3.0)
- ✅ Thin ewes (BCS <2.5)
- ❌ Limited effect in ewes already in very good condition (BCS >3.5)
4. Body Condition Management
4.1 Target BCS
- At the start of breeding: BCS 3.0-3.5 (on a 5-point scale)
- Bring thin ewes into adequate condition beforehand
- Excessively fat ewes show reduced reproductive performance
4.2 BCS Evaluation
- Evaluate 6-8 weeks before breeding
- Separate thin ewes and provide additional feeding
- Restrict feeding in over-conditioned ewes
5. Nutrition of Rams
5.1 Preparation Before Breeding
- Check condition 6-8 weeks before breeding
- Target BCS 3.5-4.0
- Foot care and health examination
- Testicular examination
5.2 Feeding Program for Rams
| Period | Daily Concentrate |
|---|---|
| Before breeding (6-8 weeks) | 0.5-0.75 kg |
| Breeding period | 0.75-1.0 kg |
| After breeding | Gradual reduction |
5.3 Key Nutrients in Ram Feeding
- Energy: Needed for mating activity
- Protein: Required for sperm production
- Zinc: Testicular function and sperm quality
- Selenium: Sperm motility
- Vitamin E: Reproductive function
6. Mineral and Vitamin Supplementation
6.1 Critical Minerals
| Mineral | Function | Source |
|---|---|---|
| Selenium | Reproduction, immunity | Premix, injection |
| Zinc | Ovulation, sperm | Premix |
| Iodine | Thyroid, reproduction | Iodized salt |
| Phosphorus | Energy metabolism | Premix |
6.2 Vitamin Supplementation
- Vitamin A: Reproductive epithelium
- Vitamin E: Antioxidant, reproduction
- Vitamin D: Calcium metabolism
7. Ram-to-Ewe Ratio
7.1 Recommended Ratios
| Ram Age | Ewes per Ram |
|---|---|
| Young ram (1-2 years) | 15-25 |
| Adult (2-5 years) | 30-50 |
| Older (>5 years) | 20-30 |
7.2 Ram Rotation
- Use more than one ram
- Allow rams to rest
- Improves conception rate
8. Management During the Breeding Period
8.1 Length of the Breeding Period
- Optimal: 35-42 days (2 estrous cycles)
- Short breeding period: more synchronized lambing
- Long breeding period: higher overall pregnancy rate
8.2 Points Requiring Attention During Breeding
- Minimize stress
- Provide sufficient shade and water
- Monitor ram health
- Observe the ewes carefully
9. Strategies to Improve Reproductive Performance
9.1 Non-Nutritional Factors
- Ram effect: Separate rams 2-3 weeks before breeding, then reintroduce them
- Light management: Shortening day length stimulates estrus
- Melatonin implants: Useful for out-of-season breeding
9.2 Genetic Selection
- Lines with high twinning rate
- Breeds carrying the Booroola gene
10. Nutrition After Breeding
10.1 Early Pregnancy (First 30 Days)
- Embryo implantation is a critical stage
- Avoid abrupt dietary changes
- Minimize stress
- Reduce flushing gradually
10.2 Preventing Embryo Loss
- Protect from excessive heat or cold
- Avoid transport and stressful procedures
- Keep away from toxins
- Provide adequate, but not excessive, nutrition
11. Common Mistakes
- ❌ Starting flushing too late
- ❌ Applying flushing to already over-conditioned ewes
- ❌ Neglecting ram preparation
- ❌ Inadequate ram-to-ewe ratio
- ❌ Stress during the breeding period
- ❌ Sudden ration changes
- ❌ Mineral deficiencies
Conclusion
Correct nutritional strategies during the breeding season can substantially improve flock reproductive performance.
Key principles:
- Assess BCS 6-8 weeks before breeding
- Apply flushing to ewes in moderate body condition
- Prepare the rams as well
- Provide mineral and vitamin supplementation
- Minimize stress during breeding
- Manage early pregnancy carefully
References
Scaramuzzi, R. J., et al. (2006). Regulation of folliculogenesis and the determination of ovulation rate in ruminants. Reproduction, Fertility and Development, 18(2), 153-165.
Martin, G. B., et al. (2004). Nutritional and environmental effects on reproduction in small ruminants. Reproduction, Fertility and Development, 16(4), 491-501.