The challenges of prohibiting the use of steroid hormones in FTAI protocols and the resulting impact on South American cattle systems
Bó, Gabriel AMenchaca, AlejoBaruselli, Pietro
The development of fixed-time artificial insemination (FTAI) protocols at the end of the 20th century has exponentially increased the number of beef cattle inseminated over the last 20 years in South America. The main reasons for this growth were the possibility of obtaining acceptable pregnancy rates without estrus detection at the beginning of the breeding season in herds with a high percentage of suckled cows in postpartum anestrus and prepubertal heifers. Most FTAI treatments in South America have been based on the use of progesterone (P4) releasing devices and estradiol to synchronize both follicular wave emergence and ovulation, with pregnancy rates ranging from 40 to 60%. The massive application of FTAI benefited farmers who use these protocols in genetic improvement and crossbreeding programs, that in turn, improved their profitability through increments in pregnancy rates, weaning weights, and the market price of their calves. It was also important for the veterinarians because it became an important source of income. Many of these practices are now apparently at risk from restrictions on the use of estradiol by the European Union (EU) and other countries. Therefore, it is imperative to develop alternative protocols that will allow us to adapt to the new times that are coming. The objective of the present review is to briefly summarize the main aspects of banning estradiol in livestock production, the negative impacts on reproductive efficiency, and to present some alternative FTAI protocols for dairy and beef cattle.(AU)
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