Research by Teagasc has shown that early nutrition is critical for high fertility and embryo survival in replacement heifers.
Early embryo loss is the major cause of reproductive failure in heifers and cows.
The effects of short-term changes in energy intake pre and post-insemination on embryo survival, have been investigated at Teagasc Athenry in beef heifers.
Embryo survival trial
The heifers were split into two groups consisting of a low-nutrition treatment and high-nutrition treatment.
The low-nutrition treatment was a grass allowance equivalent to 0.8 times maintenance, while the high-nutrition treatment was a grass allowance equivalent to twice maintenance.
The groups were then spilt into two sub-groups with half of the heifers in the low-nutrition treatment moving to the high-nutrition treatment after breeding.
Similarly half of the heifers in the high-nutrition treatment, were moved to the low-nutrition treatment after breeding.
The animals were placed on either nutrition treatment for a period of two weeks before and two weeks after artificial insemination (AI).
Results
Maintaining the plane of nutrition or increasing the plane of nutrition results in high embryo survival rates in replacement heifers.
Short-term (two-week) reduction in energy intake after AI severely reduces embryo survival rate in heifers.
The heifers maintaining a high-nutrition treatment have a 65% rate of embryo survival, compared to 38% for heifers which were moved to the low-nutrition treatment after breeding.
Similarly heifers that were on the low-nutrition treatment had a 70% survival rate, while the heifers moved to the high-nutrition treatment after breeding had a survival rate of 71%.
Conclusion
Clearly, maintaining dry matter intakes (DMI) during the early pregnancy period by avoiding sudden grass shortages is critical in achieving a high pregnancy rate in such animals.
If you run short of grass after heifers are bred, consider supplementing them to support higher embryo survival rates.