Need as indicated by stakeholders

Assessments performed by the United Nations estimated that the world population will increase by over a third between 2009 and 2050, likely reaching overall numbers to over 9 billion people (FAO). Over the same period of time, individual average incomes are also expected to increase, as shown by recent trends of growing economies in developing countries (Mensbrugghe et al., 2009). A positive correlation exists between per capita income and demand for animal food products (milk, meat, and eggs; Sans and Combris, 2015). These projections indicate that overall food production will have to increase by 70% and meat production by 42% in order to meet the demands for this growing population. Although considerable increases in food production are needed, land availability for agriculture is estimated to increase only by 5-12% (FAO, 2009).

These projections indicate that our current food production systems will have to undergo considerable changes in order to optimize production efficiency and meet the growing demand for food, while maintaining ecological stewardship and proper use of limited natural resources. Increasing reproductive efficiency of both beef and dairy cattle will contribute to the milk and meat supplies for our future food need and for the U.S. to maintain a competitive advantage in milk and meat products.

Originating more than 40 years ago, this project strives to develop solutions for reproductive inefficiencies in dairy and beef cattle by increasing efficiency and predictability of reproductive programs. This has been accomplished through evaluating mechanisms that regulate reproductive processes that impact production efficiency and disseminating reproductive management information to stakeholders to improve sustainability in both beef and dairy industries.

Importance of the work and what the consequences are if it is not done

Beef

Over the last decades several advances in reproductive biotechnologies such as estrus-synchronization and fixed-time artificial insemination (TAI) have helped producers enhance fertility, improve genetic traits of their cattle, tighten the breeding season and shorten the calving season, leading to an increase in overall efficiency of cow-calf production systems. Although significant progress has been made, and the rate of adoption of assisted reproductive technologies (ART) has increased, natural service by itself is still by far the main breeding strategy utilized in beef cow-calf operations. According to a recent USDA report, only 11.6% of the cow-calf operations in the U.S. utilize AI (USDA, 2020), whereas 89.3% of the dairy operations artificially inseminate their cows (NAHMS, 2014). Currently recommended estrus synchronization protocols for TAI in beef herds yield pregnancies rates that normally range between 40-60% (Lamb et al., 2016; Reese et al., 2020). While these results are positive, only approximately half of the calf crop from the few operations that do utilize these strategies are produced via AI, limiting the speed in which superior genetics are spread across the beef industry.

Unless commercial beef producers aggressively implement genetic improvement through the use of reproductive management, the U.S. will lose its competitive advantage to countries such as Brazil and Argentina, which are leading export countries for U.S. beef genetics. For example, according to the Association for Brazilian Artificial Insemination, there was a 285% increase on the proportion of beef cows artificially inseminated between 2002 and 2019 in Brazil. Moreover, data collected by the International Embryo Technology Society indicates that Brazil currently has greater adoption of embryo transfer technology than the U. S.

Multi-state research and extension efforts to maximize the use of reproductive technologies, such as artificial insemination and embryo transfer, are warranted and will contribute to maintaining the genetic advantage of U.S. beef herds compared with other beef producing countries. An important driver of the adoption of ART is the efficiency and predictability of these technologies. Multi-disciplinary basic and applied research to maximize the efficiency and predictability of these technologies will play an important role on the future of the U.S. beef industry.

Dairy

Over the past two decades, a reproduction revolution has occurred in the dairy industry. Based on data from nearly 20 million inseminations in >23,000 U.S. herds, phenotypic performance for reproductive outcomes in U.S. Holstein and Jersey cows as well as genetic merit for daughter pregnancy rate reversed their historical declines and began to increase in 2002 (Norman et al., 2009). Although many factors are associated with the dramatic increase in reproductive performance (genetics, nutrition, management, etc.), the development of fertility programs (for our review see Carvalho et al., 2018) and their adoption by dairy farmers (Caraviello et al., 2006) has driven much of this change. Fertility programs for TAI as well as strategies for pregnancy diagnosis and resynchronization of ovulation have not only increased the AI service rate, but also have increased pregnancies per artificial insemination (P/AI) in high-producing Holstein cows by about 10-percentage points compared to AI to a detected estrus (Santos et al., 2017).

To compensate for these changing economic conditions, dairy farms have rapidly implemented dairy herd inventory management strategies to right-size replacement heifer inventories and maximize profit. One of the key reproductive technologies they have turned to is sexed semen. Use of sexed semen increases genetic progress in dairy herds through increased dam selection intensity (Khalajzadeh et al., 2012). Other strategies include use of genomic testing or pedigrees to identify genetically superior heifers and cows, use of sexed semen to inseminate genetically superior dairy heifers and lactating cows balanced for replacement needs (Weigel et al., 2012), and use of beef semen to inseminate low genetic merit heifers and cows to produce crossbred bull calves with increased value in the beef market (Ettema et al., 2017). This has led to a rapidly evolving trend in use of sexed Holstein semen, conventional Holstein semen, and conventional beef semen to inseminate Holstein females in the U.S. Thus far in 2020, 20% of Holstein females are inseminated using sexed semen, whereas 23% of inseminations are beef semen on Holstein females.

From an economic perspective, the U.S. dairy industry has experienced a prolonged 5-year period of milk prices at or below the cost of production (USDA-NASS, 2020). Thus, for U.S. dairy farms to survive under this new economic environment, strategies to optimize reproductive management technologies must be evaluated, economically modeled, and transferred to the dairy industry.

Technical feasibility of the research

During the last 40 years, the NC-1201 have contributed greatly to the development of several breeding programs to maximize pregnancy rates. Moreover, efforts from this group addressed objections or reasons given by cattle producers for not adopting reproductive technologies. Information generated by this group led to the development of the OvSynch protocol in dairy cattle and its variations (CO-Synch protocols) used in beef cattle. These protocols increase pregnancy rates in both beef and dairy females compared to control treatments because they induce ovulation in postpartum cows that have not resumed estrous cycles by the end of the voluntary wait period (dairy cows) or at the onset of the breeding season (beef cows). Additionally, previous and ongoing multi-state collaborations from this group have contributed to the development of recommendations for management practices beyond ART that optimize the return of investment associated with the incorporation of these technologies.

The advantages of doing the work as a multistate effort

A foundational goal of this group is to generate statistically valid results that are applicable and relevant to dairy and beef farms across the U.S. The majority of the data endpoints, or pregnancy rates, collected in cattle breeding trials are binomial and require large sample sizes to test hypotheses and to be relevant to producers across the U. S. Hundreds, if not thousands, of cows across a variety of environmental conditions from Michigan and South Dakota to Texas and Mississippi are required to be confident that recommendations will work effectively for producers in all the varied environments across the U.S. and world, depending on specific questions. This group has collaborated on numerous multistate projects to provide results with increased statistical power for multiple farms. For example, several publications from this group were the product of the collaboration of at least six experiment stations. This group also actively collaborates, in a similar fashion, in the development of extension/outreach strategies to enhance both beef and dairy industry adoption of breeding programs.

Likely impacts from completing the work

Previous work from NC-1201 have already resulted in significant impacts to both beef and dairy industries, as the efforts of this group contributed to the current increase in the use of reproductive technologies in cattle. While significant progress has been made, expanding the use of currently available reproductive technologies and the development of novel reproductive management approaches will contribute to increasing beef and dairy production efficiency. Fertility is a main driver of the adoption of ART because the return of investment of such technologies increases as conception rates increase. The research and outreach of this proposal objectively addresses this issue and further detail is provided in the Methods and Outreach Plan sections of this proposal.