Retained placentas occur when a cow fails to expel the placenta within 12 hours after calving. Typically, the incidence in a herd is less than 5%. While difficult calvings can contribute to retained placentas, nutritional deficiencies are often a primary cause. Ensuring proper dietary intake of selenium, vitamin E, vitamin A, calcium, and protein before calving is crucial for prevention.
Essential Nutrients for Prevention
Selenium and Vitamin E
Selenium and vitamin E are vital for smooth muscle function, which aids in placenta expulsion. Recommended levels include:
- Selenium: 0.3 mg/kg of dry feed (6 mg/day).
- Vitamin E: 800-1,000 IU/day during the dry period.
Both nutrients should be included in the feed. While commercial mineral mixes provide selenium, vitamin E levels are often insufficient. Supplementing with a vitamin E premix, such as Vitamin E 40,000, is advisable. Feeding 25g of Vitamin E 40,000 will supply 1,000 IU of vitamin E.
Vitamin E/selenium injections can be administered 2-3 weeks before calving as a short-term measure. However, because vitamin E remains effective for only 2-3 weeks, repeated injections are necessary. Adequate vitamin E intake also supports immune function, further reducing the risk of complications.
Vitamin A
Vitamin A plays a critical role in maintaining the reproductive tract lining. A deficiency can lead to a higher incidence of retained placentas. Dry cows should receive:
- 55,000 IU/day of vitamin A, equivalent to 6g/cow/day of a vitamin A premix containing 10,000,000 IU/kg.
Calcium
Calcium is essential for smooth muscle contraction and nerve function. However, excessive calcium intake before calving can lead to milk fever, which increases the risk of retained placentas by four times. Optimal calcium levels in dry cow diets should be:
- 0.4% to 0.75% of the total diet.
To prevent milk fever, avoid excessive calcium supplementation during the dry period.
Protein
A low-protein diet during the dry period has been linked to retained placentas. Insufficient protein intake causes the placenta to grow larger in an attempt to absorb adequate protein, leading to retention issues. The ideal protein level in close-up dry cow diets is:
- Approximately 15%.
Conclusion
Proper nutritional management before calving significantly reduces the risk of retained placentas. Ensuring adequate levels of selenium, vitamin E, vitamin A, calcium, and protein can help improve reproductive health and postpartum recovery. By focusing on balanced nutrition, dairy farmers can enhance herd productivity and minimize calving-related complications.
