Research findings can be useful for individuals looking to strategize their own dairy cow breeding plans
Over the past decade, use of advanced reproductive technologies has skyrocketed in dairy breeding due to increased efficiency and accuracy of the resultant offspring. Cow farmers can use sexed semen to predict the sex of the offspring that will be produced with about 90% reliability.1 Commercial producers sort semen via flow cytometry or through selective destruction process to create samples with enriched X or Y chromosome bearing sperm cells. Alternatively, beef semen is used to create non-replacement dairy x beef crossed offspring that hold an increased market value compared to less profitable dairy bulls.
Many factors influence the decision to use sexed semen or beef semen. Sexed semen comes at an increased cost, so use in herds with poor reproductive performance may not result in a positive income from calves over semen costs (ICOSC) as much as a herd with greater reproductive performance. Additionally, sexed semen has traditionally been reserved for nulliparous cows due to lowered expected efficacy in multiparous cows. Despite knowing that the use of these techniques has increased, prior to this study no detailed data has been available to understand exactly how sexed semen and beef semen use is changing the breeding landscape.
In a study published in the Journal of Dairy Science,2 researchers evaluated the use of sexed semen and beef semen across a large proportion of dairy cattle herds in the United States. The primary objective was to determine semen type, prevalence, and allocation in Holstein and Jersey females by year, parity, service number (the number of insemination attempts), and herd size. A secondary objective was to determine the prevalence of beef bred cows with Holstein or Jersey to produce crossbred calves.
Using data from the Dairy Records Management System (DRMS), this study included records from approximately 42% and 27% of the total dairy cows and heifers, respectively, and approximately 40% of the total licensed dairy herds in the United States.2
From 2019 to 2021, inseminations of Holstein females with beef semen increased overall and tended to increase for Jersey females as service number increased. Although total inseminations with sexed semen increased for Holstein and Jersey females from 2019 to 2021, use of sexed semen decreased with increasing service number.
Dairy farmers are likely using more sexed semen at first service because of greater fertility associated with first service. Conversely, beef semen inseminations increased with increasing parity and service number for Holstein and Jersey females, respectively.2 Dairy farmers preferentially use sexed semen on younger females at first service because on average, their genetic merit and fertility are greater than that of older females. Thus, farmers allocate sexed and beef semen differently based on the cow’s service number and parity. Additionally, the data showed that increased sexed and beef semen inseminations are driven by larger dairy herds that allocate semen type based on parity and service number rather than smaller dairy herds.
This study clearly evaluates and displays the dynamic differences in the current landscape of dairy cow breeding and can be helpful for those looking to strategize their own breeding plans.
Bechtold is a 2024 PharmD candidate at the University of Connecticut