In human health, a recent breakthrough could assist a Texas A&M Department of Animal investigator in his quest to find a means to improve beef output to satisfy the demands of a growing worldwide population, according to the university.
Cattle breeds belonging to the genus Bos indicus are extremely significant to world beef production because of their adaptation to tropical and sub-tropical temperatures, including those found in Texas and other southern U.S. states, and because of their high productivity.
However, a significant obstacle or disadvantage for Bos indicus, or Brahman, cattle is that their general reproductive quality is inferior to Bos taurus cattle cows like Angus and Hereford, which prevail in the Midwest and Northern states.
Agricultural and Life Sciences assistant professor and reproductive physiologist Rodolfo Cardoso, DVM, Ph.D., is the project director for a four-year grant from the United States Department of Agriculture’s National Institute of Food and Agriculture. The grant is worth $500,000 and will be funded by the USDA’s National Institute of Food and Agriculture.
Gary Williams and Viviana Garza are collaborators. The mechanisms managing the secretion of gonadotropin-discharging hormone GnRH, according to Cardoso, have been defined as a result of revolutionary developments in neuroendocrine research.
He hopes that the new insights will assist his team in determining neuroendocrine differences between Bos taurus and Bos indicus genotypes of cattle, which they can then exploit to improve reproductive efficiency in cattle that have been influenced by Bos indicus.
According to Dr. Hein, a significant advance in understanding how the secretion of GnRH is regulated in rodents and primates was made lately.
“Our preliminary research suggests that similar systems are similarly essential in cattle and that these disparities in reproductive success between Bos taurus and Bos indicus animals may be explained by these mechanisms.”
“If those findings are validated, they could have practical ramifications for the management of Bos indicus cattle during their reproductive cycles.” Based on these innovative results, several pharmaceutical treatments to boost fertility in women have already been created in human medicine and are being tested.”
Calving timing is important.
Cattle are raised in tropical and sub-tropical climates, accounting for as much as 70% of the world’s cattle. Approximately 30% of beef herds in the United States are influenced by the Bos indicus, with the majority of these herds being in the southern and southeastern areas.
Bos species and Bos indicus-influenced cattle achieve puberty later than Bos taurus strains, which presents a significant problem. Late adolescence results in one fewer calf produced in a cow’s lifespan, and it also creates difficulties for breeders who are attempting to coordinate estrus cycles for the yearly breeding season, as previously stated.
According to Cardoso, the average age at which heifers achieve puberty is 10 to 12 months; however, heifers of the Bos indicus breed often reach puberty at 15 to 17 months.
“Because of the five-month delay, they do not reach adolescence in time for their first breeding season, and as a result, they must wait an additional year before they can be bred and produce their first calf,” Cardoso explained.
Considering that more than 4 million replacement beef heifers are introduced into the U.S. cow herd each year, the difference between having a calf when the heifers are two years old and three years old can make a significant difference in total beef output.
Attributed to the influence of the Bos indicus, less than half of beef heifers reach the age of two years when they should be calving. This is especially true in Texas and Florida.
Compared to heifers that summarize a given data set for the first time at three years of age, Cardoso claims that heifers that first calve at two years of age produce roughly 300 more pounds of weaning calf weight throughout their lives or a $500 difference in production.
Utilizing current discoveries, this research will investigate if distinct differences reported in the ability of two Bos taurus breeds to reproduce can be linked to functional differences in the brain area that controls secretion of the gonadotropin-releasing hormone.
Predetermined breeding seasons are essential to efficiency.
According to Cardoso, a specified breeding season normally lasts between 45 to 90 days and provides for more efficient management of a beef cattle enterprise, which is beneficial.
“Having a fairly homogeneous calf crop makes it much easier to manage those calves,” he explained. “You can vaccine those calves and follow all the health standards at the same time,” he added.
“Because you have a consistent group of calves, you can wean and sell them all at the same time, which makes management much more efficient in a cow-calf operation. The culling of animals that are no longer productive is also possible under this system.”
Along with improving understanding of cattle reproductive function, Cardoso stated that a second goal of using a pharmaceutical technique is to develop personalized artificial insemination protocols for Bos indicus heifers, which he described as a second goal of the strategy.
The vast majority of procedures currently in use in the United States were established expressly for the Bos taurus breeds of dogs.
According to the veterinarian, these Bos indicus heifers are 12–14 months old and have already achieved the skeletal size and maturity necessary to support a safe and healthy pregnancy. “There isn’t any doubt in my mind about that.
It’s simply that they haven’t gotten around to it yet. We don’t want to put these heifers through the process of reaching intellectual puberty (puberty before 10 months of age). That’s not ideal, and it’s not what we’re attempting to do with this project.”
According to Cardoso, one of the most significant advantages of more efficiently synchronizing the breeding season is the increased ability to perform artificial insemination in cattle influenced by the Bos indicus.
According to him, “artificial insemination is the most potent technique we have available to improve genetics in beef cow herds.” According to the National Beef Cattle Association, a beef cow rancher can use artificial insemination to improve the genetics of his herd over time.
However, according to Cardoso, the capacity of breeders to synchronize the estrus of Bos indicus-influenced animals for artificial insemination is not perfect at the moment.
We expect to have a very strong grasp of the neuroendocrine differences between Bos taurus-influenced heifers and Bos indicus-influenced heifers at the end of this four-year experiment, he said.
“More importantly, we believe that by that time, we will have developed some effective pharmaceutical techniques for controlling the estrus cycle in heifers impacted by the Bos indicus.”