Sadly, some Universities teach that fertility is not very heritable.
This claim is based off of studies that used “indicators” of fertility to study the heritability of fertility. These studies found that these indicators were not very heritable, and concluded that fertility must not be very heritable.
But any true cattleman that actually makes money in the cattle business can tell you that fertility is EXTREMELY heritable.
Perhaps these “certain indicators” in these studies aren’t good indicators for measuring fertility.
Maybe measuring how often a cow has a calf, and how old she was when she first hit puberty would be a common sense way to measure fertility.
We are conducting our own research and collecting data that helps benefit the cattlemen.
The Theories below are only theories. But, from the data that we have gathered, they are showing to be valid.
Females that can produce a calf every year on less inputs actually produce less eggs in embryo production. A large production of eggs is actually a symptom of infertility.
Therefore breeders doing embryo work and claiming their females were fertile because of their large egg production are one of the largest contributors to infertility problems in the cattle industry.
However, low egg production does not guarantee fertility. Because this relationship is only a one way relationship, this correlation is difficult to see by academics.
In the additional resources, there is a study published from Brazil that supports this theory.
Genetics that can produce a calf every year on less inputs actually have high marbling. Terrible marbling is actually highly correlated with bad fertility.
Cattlemen that have culled hard for fertility have actually been also selecting for cattle that can grade well. Marbling is the fat deposited in muscle, which is also an extra source of energy that a cow can use for when resources are limited. Cattle that don’t marble well would also be the animals that burn muscle when resources are limited, which would lead to them getting culled from the herd in a cattleman’s operation.
However, high marbling does not guarantee fertility. Breeders only working on carcass qualities are most likely contributing to infertility problems. Because this relationship is only a one way relationship, this correlation is difficult to see by academics.
We do not think it is a coincidence that breeds of cattle known for fertility problems are also known to have bad carcass qualities, exactly like the American Brahman. This is true for how some breeds known for fertility are also known to have great carcass qualities, exactly like traditional Angus.
Genetics that can produce a calf every year on less inputs actually have shorter gestation lengths.
In Australia, there is already data and studies that support this theory. But, we have heard from customers that have AI’d with our bulls that the calves are born at a sooner date compared to other sires that were from the more “popular/ show” genetics. Also, when it comes to calving out our embryo calves, we never have to induce labor. And the majority of our calves are born before the due date, while it is very common for brahman ET calves to be born well after their due date.
Regardless, we will be studying this phenomenon heavily from breeders that are using our genetics around the world.
Dummy calf syndrome is a symptom of infertility.
Around the world, breeders of sustainable genetics have seen that they have lower cases of dummy calf syndrome, whether it be from natural calves or embryo calves being born. We find it a small coincidence that these same breeders believe in natual selection, and that most likely when a calf is born without the natural instinct to live, Mother Nature is saying that this calf is not supposed to survive.
More fertile females ovulate faster and respond faster to sychronization protocals.
This means the more fertile females respond faster to synchronization drugs. A more fertile female would need to be AI’d at a quicker time compared to a less fertile female. Because of the misconception, there is a good chance that the most fertile females have been culled from operations that utilize artificial insemination. The most fertile females actual need to be inseminated at an earlier time compared to females with fertility levels of the more generic cattle of today’s standards.
We find it interesting that Brahman cattle in Bolivia have a protocol similar to Bos Tauras cattle in the U. S. when the Brahman cattle in Bolivia have been selected for fertility.