Date of Award
Master of Science (MS)
Animal and Veterinary Sciences
Nathan M. Long
Scott L. Pratt
Charles F. Rosenkrans Jr.
Reproductive function is crucial to the success of a beef or dairy herd. Both the female and male play significant roles in the outcome of bovine reproduction. The bull contributes to reproductive success in many ways, such as genetics. The initial role that the bull has in reproductive success is fertilization, whether natural or by artificial insemination. One method of assessing bull performance are central bull test stations, which are traditionally administered by a university, extension center, or are privately owned. Central bull tests assess the performance of bulls from various management systems, breeds, and ages. Some measurements taken during a central bull test are body weight, and a breeding soundness exam (BSE) is usually administered at some point during the test. Bull BSEs are the golden standard for predicting breeding potential in bulls by assessing structural soundness, semen motility, semen morphology, and SC. These factors are significant to ensuring that the bull has the ability to breed.
Many events can occur making reproduction unsuccessful such as, failure of bull to breed, anestrous, fertilization failure, and pregnancy loss. Pregnancy loss varies between beef and dairy cattle with lactating dairy and beef cattle having a pregnancy loss rate of 50-60% and 10.8-48% respectively (Stevenson et al., 2003; J. E.P. Santos et al., 2004; Wiltbank et al., 2016; S T Reese et al., 2020). Detecting pregnancy loss early in gestation is crucial to the reproductive success of cattle. Standard methods of bovine pregnancy diagnosis include rectal palpation, transrectal ultrasonography, enzyme linked immunoabsorbant assays for pregnancy association glycoproteins. Other methods being examined for bovine pregnancy diagnosis include interferon-tau (INF-T), maternal progesterone concentrations, and microRNA (miRNA) expression. Profiled miRNAs have been associated with pregnancy and pregnancy loss, specifically, uterine miRNAs are implicated with embryo adhesion and attachment. MicroRNAs (miRNA) are a class of small, non-coding, endogenous, and evolutionarily conserved RNAs that range in size from 19 to 24 nucleotides in length (Lagos-Quintana et al., 2003; Bhaskaran and Mohan, 2014). MiRNAs have been used as biomarkers for various health issues and physiological states in both humans and animals (Kroh et al., 2007). The objective of this study is to evaluate aspects of bovine reproduction function pertaining to the male using performance data and microRNA expression in females at d 30 of gestation.
Amiss, Erin, "An Evaluation of Bovine Reproductive Function from the MicroRNA Expression in the Female to Performance Testing in the Male" (2022). All Theses. 3947.