How to achieve optimal reproduction in cows

Optimal reproduction is critical for all cattle farming operations. All farms strive to select for the most fertile animal under their specific environmental conditions. However, genetics selection is not the only method to obtain improved cow efficiency. It can also be improved through accurate and timely supplementation of key nutrients in critical periods.

The high-pressure production systems found in commercial agriculture today require the most efficient cow for a certain environment. This means having the right animal for the environmental conditions present per farm and ensuring that that cow produces a calf every year. Cows should be well supplemented during the key periods and as a result, should not skip a breeding season. A more economically valuable herd translates to farms that generally sell more weaners per year and have better incomes.

A low reproduction rate makes a herd less efficient. This lowered cow efficiency can have multiple causes, one of which is a deficiency of beta-carotene. Beta-carotene is a carotenoid substance, which gives certain plants (such as carrots and sweet potatoes) their reddish colors. Beta-carotene has various functions and benefits, namely:

  • Important provitamin A (used by the body to make vitamin A).
  • Acts as an antioxidant.
  • Affects follicle quality and corpus luteum.
  • Promotes progesterone synthesis.

Beta- carotene and fertility

Beta-carotene can improve cow fertility by having a positive effect on the cow’s ovulation. This positive effect is due to beta-carotene being important for luteal function regulation, which can be seen in the decreased risk of early embryonic death. During ovulation, a mature follicle (small sacs filled with fluid) that is situated on the ovary will burst and release an egg. This ruptured follicle will then form the corpus luteum. The corpus luteum is a steroidogenic gland rich in beta-carotene, which is formed on the ovary after ovulation. This gland produces the hormone progesterone, which is essential to prepare the inner lining of the uterus (endometrium) where a fertilized egg can attach to. Progesterone also helps to maintain the pregnancy when an egg is successfully implanted within the uterus lining.

Figure 1: Ovulation and the structures involved.

Beta-carotene levels within the corpus luteum have a positive correlation with the size and weight of the corpus luteum; in other words, more beta-carotene results in a larger corpus luteum. Progesterone production will increase with an increased corpus luteum size, resulting in higher pregnancy rates. Within the first six-16 days of the estrus cycle, there is an increase of nearly six times the normal levels of beta carotene. By supplementing your animals with beta-carotene, you can ensure that the animals’ beta carotene requirements are met, and that high reproductive performance can be reached.

Effect of antioxidants

Another benefit of beta-carotene is its antioxidant activity. Antioxidants are compounds that inhibit oxidation and protect cells from free radicals. The antioxidant effect helps to increase the quality of the egg ovulated by protecting various cells and its contents such as mitochondria. Mitochondria have a major role in cellular energy production and supplies the energy required for regulatory cellular functions. When a fertilized egg attaches to the endometrium, it will continue to develop into an embryo through a series of divisions and maturation processes called mitosis. This process is highly dependent on energy being freely available. A cell under oxidative stress lacks the ability to function normally and translates to mitochondria being unable to produce energy. Therefore, supplementation of beta-carotene can improve the health of cells and improve the reproductive process.

Level up on nutrition

One of the main driving factors for beta-carotene deficiency is poor nutrition. Beta-carotene concentration typically declines as forages age, with no effect from different harvesting seasons, number of harvests or regrowth. This decline results in the cows receiving lower levels of beta carotene, which lowers the beta-carotene levels within the corpus luteum. The degeneration is even worse when poor forage management is practiced. When rain interrupts the hay making process, 83% of carotenoids can be lost from the roughage, when measured directly after cut and then at hay. Solar radiation is another cause for preserved forages to lose beta-carotene during storage. In well- managed silage, the beta-carotene levels lost can be as low as 20%, but when roughage is ensiled poorly, the losses can go up to 80%. To prevent that this loss of beta-carotene carries over to our cows and reduces their fertility, nutrient supplementation becomes a key management factor.

In conclusion

Efficient cows are essential in our herd due to them having a high economic value. With the feeding of roughage alone, farmers cannot be guaranteed the nutritional support the high intensity that modern production systems require. This is where supplemental nutrition plays an important role in reaching the desired reproductive rate. With the supplementation of nutrients like beta-carotene, we can ensure our cows receive adequate amounts of these carotenoids and thereby ensure optimal reproduction efficiency within the herd.

Tian Bezuidenhout
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